化工百科
  • 首页
  • 产品
  • 热点
  • 常用手册
  • 供应商后台
  • 了解会员服务
  • 登录
  • 注册
  • CAS 6250 (English)

CAS 6250 显示CAS号以6250为起始的化合物

  1. 主页
  2. CAS
  3. CAS 6250
  4. 本页面热门标签 : 制剂-拮抗剂
ID CAS 中文名 英文名 化学式 分类 Tag
16250-12-01H-Benzo[a]cyclopenta[f]quinolizinium, 2,3,3a,5,6,11,12,12a-octahydro-8-hydroxy-C16H20NO
26250-21-13,10-Dioxa-2,11-disiladodecane3,10-Dioxa-2,11-disiladodecaneC8H22O2Si2
36250-23-3分散黄23Disperse Yellow 23C18H14N4O颜料;颜料及染料类
46250-24-4非奈利酮杂质1542H,6H-1,5-Dioxocin-2,6-dione, 4,8-dimethyl-C8H8O4
56250-36-8Carbonodithioic acid, O-octadecyl esterC19H38OS2
66250-49-32,8-Dimethylnaphtho[3,2,1-kl]xanthen-9-ol acetate2,8-Dimethylnaphtho[3,2,1-kl]xanthen-9-ol acetateC24H18O3
76250-70-0十九烷二酸1,17-Heptadecanedicarboxylic AcidC19H36O4
86250-72-218-甲基十九烷酸18-METHYLNONADECANOIC ACIDC20H40O2甲基脂肪酸
96250-73-34,8-dimethylnona-3,7-dienenitrile4,8-dimethylnona-3,7-dienenitrileC11H17N
106250-76-6N-methylglycinamideN-methylglycinamideC3H8N2O
116250-80-24-乙基-3,5-二甲基-1H-吡咯-2-甲醛4-Ethyl-3,5-dimethyl-1H-pyrrole-2-carbaldehydeC9H13NO
126250-88-03,4-dihydropyrano[3,4-b]indol-1(9H)-one3,4-dihydropyrano[3,4-b]indol-1(9H)-oneC11H9NO2
136250-96-05H-Cyclopenta[d]pyridazine, 6,7-dihydro-5H-Cyclopenta[d]pyridazine, 6,7-dihydro-C7H8N2
1462500-87-21H-Indole-2-ethanamine, N,N,β,5-tetramethyl-1H-Indole-2-ethanamine, N,N,β,5-tetramethyl-C14H20N2
1562500-88-32-(5-ethyl-1H-indol-3-yl)ethanamine2-(5-ethyl-1H-indol-3-yl)ethanamineC12H16N2
1662500-90-72-(6-methyl-1H-indol-3-yl)ethanamine2-(6-methyl-1H-indol-3-yl)ethanamineC11H14N2
1762501-24-01-(3,7,7-trimethylbicyclo[4.1.0]heptenyl)ethan-1-one1-(3,7,7-trimethylbicyclo[4.1.0]heptenyl)ethan-1-oneC12H18O
1862501-37-5ChamonixinChamonixinC17H14O5
1962501-39-75-苯基-3,6-二氢-2H-1,3,4-噁二嗪-2-酮3,6-dihydro-5-phenyl-2H-1,3,4-oxadiazin-2-oneC9H8N2O2
2062501-40-0methyl (2-hydroxy-1-phenylethylidene)carbazatemethyl (2-hydroxy-1-phenylethylidene)carbazateC10H12N2O3
2162501-41-1羧基甲氧基琥珀酸钠盐Butanedioic acid, (carboxymethoxy)-, sodium salt
2262501-45-54,6-二甲基-1H-嘧啶-2-硫酮盐酸盐4,6-dimethyl-1H-pyrimidine-2-thione hydrochlorideC6H8N2S.ClH
2362501-51-35,9,11-Trihydroxy-3,3-dimethyl-6,8-bis(3-methyl-2-butenyl)pyrano[3,2-a]xanthen-12(3H)-one5,9,11-Trihydroxy-3,3-dimethyl-6,8-bis(3-methyl-2-butenyl)pyrano[3,2-a]xanthen-12(3H)-oneC28H30O6
2462501-53-55,9,11-Tris(acetyloxy)-3,3-dimethyl-6,8-bis(3-methyl-2-butenyl)pyrano[3,2-a]xanthen-12(3H)-one5,9,11-Tris(acetyloxy)-3,3-dimethyl-6,8-bis(3-methyl-2-butenyl)pyrano[3,2-a]xanthen-12(3H)-oneC34H36O9
2562501-54-611-Hydroxy-5,9-dimethoxy-3,3-dimethyl-6,8-bis(3-methyl-2-butenyl)pyrano[3,2-a]xanthen-12(3H)-one11-Hydroxy-5,9-dimethoxy-3,3-dimethyl-6,8-bis(3-methyl-2-butenyl)pyrano[3,2-a]xanthen-12(3H)-oneC30H34O6
2662501-55-72,3-Dihydro-5,9,11-trihydroxy-3,3-dimethyl-6,8-bis(3-methylbutyl)pyrano[3,2-a]xanthen-12(1H)-one2,3-Dihydro-5,9,11-trihydroxy-3,3-dimethyl-6,8-bis(3-methylbutyl)pyrano[3,2-a]xanthen-12(1H)-oneC28H36O6
2762501-63-71H-Pyrrole-3-carboxaldehyde, 2,5-dihydro-2-(hydroxymethyl)-1-methyl- (9CI)1H-Pyrrole-3-carboxaldehyde, 2,5-dihydro-2-(hydroxymethyl)-1-methyl- (9CI)C7H11NO2
2862501-72-8(R)-2-羟甲基-1,4-苯并二恶烷1,4-Benzodioxin-2-methanol,2,3-dihydro-, (2R)-C9H10O3
2962502-00-5(E)-3'-hydroxy-3,4,5'-trimethoxystilbene(E)-3'-hydroxy-3,4,5'-trimethoxystilbeneC17H18O4
3062502-02-7Benzoic acid, 3-ethoxy-5-methoxy-, methyl esterBenzoic acid, 3-ethoxy-5-methoxy-, methyl esterC11H14O4
3162502-03-83-乙氧基-5-甲氧基苯甲酸3-Ethoxy-5-methoxybenzoic acidC10H12O4
3262502-04-9 β-D-Glucopyranoside, 3-(acetyloxy)-5-[(1E)-2-[4-(acetyloxy)phenyl]ethenyl]phenyl, tetraacetate (9CI)C32H34O14
3362502-10-7ChromolaeninChromolaeninC15H16O
3462502-11-8(-)-4,5,5a,6,7,8-Hexahydro-1,5-dimethyl-8-methylenenaphtho[2,1-b]furan-6-ol acetate(-)-4,5,5a,6,7,8-Hexahydro-1,5-dimethyl-8-methylenenaphtho[2,1-b]furan-6-ol acetateC17H20O3
3562502-71-0甘油-1,1,2,3,3-d5Glycerol-1,1,2,3,3-d5C3H3D5O3同位素试剂;同位素标记物
3662504-27-2L-Histidine, N-[(1R)-1-carboxyethyl]-C9H13N3O4
3762506-05-2Cyclopenta[c]pyrrole-1,3(2H,3aH)-dione, tetrahydro-, (3aR,6aS)-rel-Cyclopenta[c]pyrrole-1,3(2H,3aH)-dione, tetrahydro-, (3aR,6aS)-rel-C7H9NO2
3862506-10-9Imidazo[2,1-b]thiazol-5-ol,2,3,5,6-tetrahydro-6,6-diphenyl-C17H16N2OS
3962506-24-51H-2,1,3-Benzothiadiazin-4(3H)-one, 3-(1,1-dimethylethyl)-, 2,2-dioxide1H-2,1,3-Benzothiadiazin-4(3H)-one, 3-(1,1-dimethylethyl)-, 2,2-dioxideC11H14N2O3S
4062506-35-81,2-Oxathiocane1,2-OxathiocaneC6H12OS
4162506-41-6thieno[2,3-c][1,6]naphthyridinethieno[2,3-c][1,6]naphthyridineC10H6N2S
4262506-44-9THIENO[2,3-C][1,5]NAPHTHYRIDINETHIENO[2,3-C][1,5]NAPHTHYRIDINEC10H6N2S
4362506-63-2乙二醛单-二甲基腙(DIMETHYLHYDRAZONO)ACETALDEHYDEC4H8N2O
4462506-76-72-(4-甲基苯基)吡咯烷2-(4-methylphenyl)pyrrolidineC11H15N
4562506-88-1N-苯亚甲基-N-(二苯甲基)胺N-BENZYLIDENE-N-(DIPHENYLMETHYL)AMINEC20H17N
4662507-01-13'-BENZYLOXY-5,7-DIHYDROXY-3,4'-DIMETHOXYFLAVONE3'-BENZYLOXY-5,7-DIHYDROXY-3,4'-DIMETHOXYFLAVONEC24H20O7
4762507-48-6N-(4-acetylphenyl)-4-nitrobenzamideN-(4-acetylphenyl)-4-nitrobenzamideC15H12N2O4
4862507-50-04-bromo-N-(4-nitrophenyl)benzamide4-bromo-N-(4-nitrophenyl)benzamideC13H9BrN2O3
4962507-55-52-(4-BROMOPHENYL)-5-(4-NITROPHENYL)-1,3,4-OXADIAZOLE2-(4-BROMOPHENYL)-5-(4-NITROPHENYL)-1,3,4-OXADIAZOLEC14H8BrN3O3
5062507-63-5N-亚硝基-2-肼基乙醇Ethanol, 2-(1-nitrosohydrazinyl)-C2H7N3O2
5162507-76-0dexpanthenoldexpanthenolC9H19NO4
5262507-78-24-氨基苯甲酸烯丙酯allyl 4-aminobenzoateC10H11NO2
5362507-84-0Benzoic acid, 3-(4-carboxyphenoxy)-Benzoic acid, 3-(4-carboxyphenoxy)-C14H10O5
5462507-85-14-(3-methylphenoxy)benzoic acid4-(3-methylphenoxy)benzoic acidC14H12O3
5562507-86-23-(4-METHYLPHENOXY)BENZOIC ACID3-(4-METHYLPHENOXY)BENZOIC ACIDC14H12O3
5662507-87-31H-Inden-1-one, 3-hydroxy-2-[1-(hydroxyimino)propyl]-C12H11NO3
57625078-21-9ethyl 4-[3-(1-azepanyl)-2,5-dioxo-1-pyrrolidinyl]benzoateethyl 4-[3-(1-azepanyl)-2,5-dioxo-1-pyrrolidinyl]benzoateC19H24N2O4
58625078-84-4N-(5-Amino-2-chlorophenyl)-2-thiophenecarboxamideN-(5-Amino-2-chlorophenyl)-2-thiophenecarboxamideC11H9ClN2OS
59625079-73-42-Pyridinecarboxaldehyde,4-(dimethylamino)-6-methyl-(9CI)2-Pyridinecarboxaldehyde,4-(dimethylamino)-6-methyl-(9CI)C9H12N2O
60625079-74-52-(1- 吡咯烷甲基)苯甲醛1-(2-CARBOXALDEHYDEBENZYL)PYRROLIDINEC12H15NO
6162508-00-3Ethanone, 2-[(1,1-dimethylethyl)(phenylmethyl)amino]-1-[4-hydroxy-3-(1-piperidinylmethyl)phenyl]-C25H34N2O2
6262508-01-4Ethanone, 2-[(1,1-dimethylethyl)amino]-1-[4-hydroxy-3-(1-piperidinylmethyl)phenyl]-C18H28N2O2
6362508-02-5Benzenemethanol, α-[[(1,1-dimethylethyl)amino]methyl]-4-hydroxy-3-(1-piperidinylmethyl)-C18H30N2O2
6462508-03-6Ethanone, 2-[(1,1-dimethylethyl)amino]-1-[4-hydroxy-3-(4-morpholinylmethyl)phenyl]-C17H26N2O3
6562508-04-7Benzenemethanol, α-[[(1,1-dimethylethyl)amino]methyl]-4-hydroxy-3-(4-morpholinylmethyl)-C17H28N2O3
6662508-15-0Ethanone, 2-[(1,1-dimethylethyl)(phenylmethyl)amino]-1-(4-hydroxyphenyl)-Ethanone, 2-[(1,1-dimethylethyl)(phenylmethyl)amino]-1-(4-hydroxyphenyl)-C19H23NO2
6762508-17-2Ethanone, 1-(4-hydroxyphenyl)-2-[(1-methylethyl)(phenylmethyl)amino]-C18H21NO2
6862508-20-7Ethanone, 2-[cyclohexyl(phenylmethyl)amino]-1-(4-hydroxyphenyl)-C21H25NO2
6962508-23-05-Hepten-3-one, 2-methyl-6-(5-methyl-2-furanyl)-, (E)- (9CI)C13H18O2
7062508-25-26-Hepten-3-one, 2-methyl-6-(5-methyl-2-furanyl)-C13H18O2
7162508-27-4Furan, 2-methyl-5-(5-methyl-1-methylenehexyl)-C13H20O
7262508-29-6Rhodium, tris[(1,2,5,6-η)-1,5-cyclooctadiene]tris[μ-(1H-imidazolato-N1:N3)]tri- (9CI)C33H33N6Rh3
7362508-38-7Propanenitrile, 3-[[2-(2-cyanoethoxy)ethyl]thio]-C8H12N2OS
7462508-39-8Propanenitrile, 3-(hexylthio)-C9H17NS
7562508-40-1Propanenitrile, 3-[(3-methylphenyl)thio]-C10H11NS
7662508-41-2Propanenitrile, 3-[(4,5-dihydro-5-thioxo-1,3,4-thiadiazol-2-yl)thio]-C5H5N3S3
7762508-42-31,3-二丁基-1,3-二乙基脲Urea, N,N'-dibutyl-N,N'-diethyl-C13H28N2O
7862508-60-51H-Benzimidazole-6-acetic acid, 2-(4-chlorophenyl)-, hydrochloride (1:1)C15H12Cl2N2O2
7962508-79-63-[4-(2-METHOXYPHENYL)PIPERAZIN-1-YL]-3-OXOPROPANENITRILE3-[4-(2-METHOXYPHENYL)PIPERAZIN-1-YL]-3-OXOPROPANENITRILEC14H17N3O2
8062508-87-62-(4-chlorophenyl)-4-(9H-fluoren-9-ylidene)-2,4-dihydro-3H-pyrazol-3-one2-(4-chlorophenyl)-4-(9H-fluoren-9-ylidene)-2,4-dihydro-3H-pyrazol-3-oneC22H13ClN2O
81625080-60-64-氯-6,7-二氟喹唑啉4-CHLORO-6,7-DIFLUOROQUINAZOLINEC8H3ClF2N2
82625080-70-86-Fluoro-7-(piperazin-1-yl)-N-(thiophen-3-ylmethyl)quinazolin-4-amine6-Fluoro-7-(piperazin-1-yl)-N-(thiophen-3-ylmethyl)quinazolin-4-amineC17H18FN5S
83625080-88-82-(苯并[D]噻唑-2-基磺酰基)乙酸2-(1,3-benzothiazole-2-sulfonyl)acetic acidC9H7NO4S2
84625081-86-9Azacyclohepta-1,2,4,6-tetraene,3,7-bis(1-methylethyl)-(9CI)Azacyclohepta-1,2,4,6-tetraene,3,7-bis(1-methylethyl)-(9CI)C12H17N
85625081-93-87-Azabicyclo[4.1.0]hepta-2,4,6-triene,1,5-bis(1-methylethyl)-(9CI)7-Azabicyclo[4.1.0]hepta-2,4,6-triene,1,5-bis(1-methylethyl)-(9CI)C12H17N
86625082-83-9Grela 1代催化剂Ruthenium, dichloro[[2-(1-Methylethoxy-κO)-5-nitrophenyl]Methylene-κC](tricyclohexylphosphine)-, (TB-5-23)-C28H44Cl2NO3PRu催化剂;有机试剂
87625084-56-22-Oxetanone,3-(2-pyridinyl)-(9CI)2-Oxetanone,3-(2-pyridinyl)-(9CI)C8H7NO2
88625086-90-04-Piperidinone, 1-acetyl-2,6-dimethyl-, (2R,6R)-rel- (9CI)4-Piperidinone, 1-acetyl-2,6-dimethyl-, (2R,6R)-rel- (9CI)C9H15NO2
89625087-35-6Tricyclo[3.3.1.02,4]nonane-2,6-diol, (1S,2R,4R,5R,6R)- (9CI)Tricyclo[3.3.1.02,4]nonane-2,6-diol, (1S,2R,4R,5R,6R)- (9CI)C9H14O2
90625088-17-7Hydrazinecarboxylic acid, 2-(1-cyano-1-methylethyl)-, 1,1-dimethylethyl esterHydrazinecarboxylic acid, 2-(1-cyano-1-methylethyl)-, 1,1-dimethylethyl esterC9H17N3O2
9162509-10-8MR-2096ClMR-2096ClC21H26ClNO5
9262509-26-6雄烯二醇杂质1Androsta-5,9(11)-dien-17-one, 3-hydroxy-, (3β)-C19H26O2
9362509-87-92,5,6-TRIMETHYL-3-ETHYLBENZOXAZOLIUM IODIDE2,5,6-TRIMETHYL-3-ETHYLBENZOXAZOLIUM IODIDEC12H16INO
9462509-93-74,9-DIAZADISPIRO[2.2.2.2]DECANE4,9-DIAZADISPIRO[2.2.2.2]DECANEC8H14N2
95625090-55-3FMOC-LYS(BOC)-COCH2CL(9H-Fluoren-9-yl)MethOxy]Carbonyl Lys(Boc)-COCH2ClC27H33ClN2O5
96625090-81-5(1-METHYL-1H-INDOL-3-YL)(MORPHOLINO)METHANONE(1-METHYL-1H-INDOL-3-YL)(MORPHOLINO)METHANONEC14H16N2O2
97625090-96-2Dinaphtho[2,1-d:1',2'-f][1,3,2]dioxaphosphepin-4-amine, N,N-diethyl-8,9,10,11,12,13,14,15-octahydro-, (11bS)- (9CI)Dinaphtho[2,1-d:1',2'-f][1,3,2]dioxaphosphepin-4-amine, N,N-diethyl-8,9,10,11,12,13,14,15-octahydro-, (11bS)- (9CI)C24H30NO2P
98625090-99-51-(8,9,10,11,12,13,14,15-八氢二萘并[2,1-d:1',2'-f][1,3,2]二氧杂膦4-基)吡咯烷1-(8,9,10,11,12,13,14,15-octahydrodinaphtho[2,1-d:1',2'-f][1,3,2]dioxaphosphepin-4-yl)pyrrolidineC24H28NO2P膦配体;有机配体
99625092-10-6N-((4R,7R,10R,13S,16S,19R)-19-(((S)-1-(((S)-1-((S)-2-((R)-1-氨基-1-氧代丙烷-2-基)氨基甲酰基)吡咯烷-1-基)-6-(异丙基氨基)-1-氧代己基-2-基)氨基)-4-甲基-1-氧代戊烷-2-基)氨基甲酰基)-7-(4-氯苄基)-13-(羟甲基)-4-(萘-2-基甲基)-16-(4-(烟酰胺基)丁基)-2,5,8,11,14,17-六氧代- 10-(吡啶-3-基甲基)-3,6,9,12,15,18-六氮杂二十三烷-23-基)烟酰胺乙酸盐Antide AcetateC84H112ClN17O16制剂-拮抗剂制剂-拮抗剂
100625094-18-04-Imidazolidinone,3-(2-hydroxyethyl)-2-thioxo-(9CI)4-Imidazolidinone,3-(2-hydroxyethyl)-2-thioxo-(9CI)C5H8N2O2S
101625094-32-83-(4-aminophenyl)imidazolidine-2,4-dione3-(4-aminophenyl)imidazolidine-2,4-dioneC9H9N3O2
102625095-27-4Cyclopentanecarboxylic acid, 2-[[(phenylmethoxy)carbonyl]amino]-,(1R,2S)-Cyclopentanecarboxylic acid, 2-[[(phenylmethoxy)carbonyl]amino]-,(1R,2S)-C14H17NO4
103625095-50-31H-Indole-2-carboxylic acid, 1-[(2S)-2-[[(1S)-1-(ethoxycarbonyl)butyl]amino]-1-oxopropyl]-2,3,4,5,6,7-hexahydro-, (2S)- (9CI)C19H30N2O5
104625095-56-9(S)-3-(3-氯苯基)-3-羟基丙酸(S)-3-(3-Chlorophenyl)-3-hydroxypropanoic acidC9H9ClO3手性酸
105625095-57-0(S)-1-(3-氯苯基)-1,3-丙二醇(S)-1-(3-Chlorophenyl)-1,3-propanediolC9H11ClO2
106625095-58-1Phosphonic acid, [[2-(9H-purin-9-yl)ethoxy]methyl]-, diethyl ester (9CI)Phosphonic acid, [[2-(9H-purin-9-yl)ethoxy]methyl]-, diethyl ester (9CI)C12H19N4O4P
107625095-60-5帕拉德福韦pradefovirC17H19ClN5O4P
108625095-61-6Pradefovir mesylatePradefovir mesylateC18H23ClN5O7PS
109625095-76-3Phosphonic acid, P-?(12,?12,?13,?13,?14,?14,?15,?15,?16,?16,?17,?17,?18,?18,?19,?19,?19-?heptadecafluorononad?ecyl)?-Phosphonic acid, P-?(12,?12,?13,?13,?14,?14,?15,?15,?16,?16,?17,?17,?18,?18,?19,?19,?19-?heptadecafluorononad?ecyl)?-C19H24F17O3P
110625096-18-6葡萄醇 DViniferol DC42H32O9标准品;其它酚类;植物提取物;分析试剂标准品;标准品 -对照药材
111625096-72-21,3-BIS(2-PYRIDYLTHIO)PROPANE1,3-BIS(2-PYRIDYLTHIO)PROPANEC13H14N2S2
112625098-86-43-羟基-7,8-二氢-1,6-萘啶-6-(5H)-羧酸叔丁酯tert-butyl 3-hydroxy-7,8-dihydro-1,6-naphthyridine-6(5H)-carboxylateC13H18N2O3
113625098-87-56-benzyl-5,6,7,8-tetrahydro-1,6-naphthyridin-3-olC15H16N2O
114625098-88-65,6,7,8-四氢-1,6-萘啶-3-醇盐酸盐5,6,7,8-Tetrahydro-1,6-naphthyridin-3-ol hydrochlorideC8H11ClN2O
115625099-16-33-Oxa-bicyclo[3.2.1]octan-8-one3-Oxa-bicyclo[3.2.1]octan-8-oneC7H10O2
116625099-19-6Spiro[1,3-dioxolane-2,8-[3]oxabicyclo[3.2.1]octane] (9CI)Spiro[1,3-dioxolane-2,8-[3]oxabicyclo[3.2.1]octane] (9CI)C9H14O3
117625099-23-23-(Trifluoromethoxy)-5,6,7,8-tetrahydro-1,6-naphthyridine3-(Trifluoromethoxy)-5,6,7,8-tetrahydro-1,6-naphthyridineC9H9F3N2O
118625099-24-3Methanone, (7,8-dihydro-3-nitro-1,6-naphthyridin-6(5H)-yl)phenyl-Methanone, (7,8-dihydro-3-nitro-1,6-naphthyridin-6(5H)-yl)phenyl-C15H13N3O3
119625099-25-4(3-amino-7,8-dihydro-1,6-naphthyridin-6(5H)-yl)(phenyl)methanone(3-amino-7,8-dihydro-1,6-naphthyridin-6(5H)-yl)(phenyl)methanoneC15H15N3O
120625099-31-23,3-二甲基二氢-2H-吡喃-4(3H)-酮3,3-DiMethyldihydro-2H-pyran-4(3H)-oneC7H12O2
121625099-32-33,3-二甲基-2,3-二氢吡喃-4-酮3,3-Dimethyl-2,3-dihydropyran-4-oneC7H10O2
122625099-34-53-氯-7,8-二氢-1,6-萘啶-6-(5H)-羧酸叔丁酯3-Chloro-7,8-dihydro-1,6-naphthyridine-6(5H)-carboxylic Acid 1,1-Dimethylethyl EsterC13H17ClN2O2
123625099-39-01,6-Naphthyridine-6(5H)-carboxylic acid, 3-(difluoromethoxy)-7,8-dihydro-, 1,1-dimethylethyl esterC14H18F2N2O3
124625099-99-23-BroMo-6-(phenylsulfonyl)-5,6,7,8-tetrahydro-1,6-naphthyridine3-BroMo-6-(phenylsulfonyl)-5,6,7,8-tetrahydro-1,6-naphthyridineC14H13BrN2O2S
  • 首页
  • 注册供应商
  • 会员介绍
  • 联系方式
  • 化工百科英文站

使用化工百科前必读