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541.
制备不同萌发时期绿豆SOD(超氧化物歧化酶)粗酶液,筛选出酶比活力最高的时期,并运用热变性、硫酸铵分级、DEAE-Sepharose FF阴离子交换层析和Sephacryl S-100 HR分子筛层析分离纯化并作对比考察,提纯的SOD进行了理化性质研究。结果表明,绿豆种子萌发第3天时SOD的比活力最高,经纯化获得的SOD酶比活力为2256.4 U/mg,纯化倍数为3.9。绿豆中SOD为Cu/Zn SOD和Mn SOD,分子量为68KD,热稳定性高,在pH5-8条件下稳定,对高浓度SDS具有抗性。EDTA可以一定程度上抑制SOD活性,H2O2可以完全抑制SOD活性。 相似文献
542.
A historical perspective on the discovery of statins 总被引:1,自引:0,他引:1
Akira ENDO 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2010,86(5):484-493
Cholesterol is essential for the functioning of all human organs, but it is nevertheless the cause of coronary heart disease. Over the course of nearly a century of investigation, scientists have developed several lines of evidence that establish the causal connection between blood cholesterol, atherosclerosis, and coronary heart disease. Building on that knowledge, scientists and the pharmaceutical industry have successfully developed a remarkably effective class of drugs—the statins—that lower cholesterol levels in blood and reduce the frequency of heart attacks. 相似文献
543.
建立了一种采用毛细管电泳法(CE)测定二氢叶酸还原酶(DHFR)反应动力学参数的新方法。以含0.002%Brij-35的50 mmol/L 的硼砂缓冲溶液(pH 9.18)作为电泳介质,检测波长280 nm,于19 min内实现了体系中各组分的基线分离。根据酶反应过程中反应物和反应产物的浓度变化计算有关反应动力学参数。将已知的氨甲喋呤、甲氧苄胺嘧啶和叶酸3种抑制剂作用于所建立的二氢叶酸还原酶体系,测得抑制剂的半数抑制浓度与文献值相接近,证明本体系可用于二氢叶酸还原酶抑制剂(DHFRI)的筛选。 相似文献
544.
Voltammetric responses of the O2/O
2
•−
couple as a function of aprotic solvents are investigated. The results show that acetone is a suitable solvent for examining
the electrode reaction of the O2/O
2
•−
couple. Studying the electrochemical behavior of the O2/O
2
•−
couple at different electrodes in acetone by cyclic voltammetry suggests that the reversibility of the O2/O
2
•−
couple and the redox peak currents at glassy carbon are better than those at gold and platinum. The kinetic parameters (electron
transfer rate constant k
0 and cathodic transfer coefficient α) of the oxygen reduction to superoxide ion (O
2
•−
) are evaluated using normal-pulse voltammetry. The obtained values of k
0 (cm/s) and α are (1.95 ± 0.05) × 10−4 and 0.34 ± 0.01, respectively. The scavenging activities of ascorbic acid and bilirubin are tested and the experimental results
confirm that ascorbic acid is a better scavenger toward O
2
•−
.
Published in Russian in Elektrokhimiya, 2007, Vol. 43, No. 2, pp. 188–194.
The text was submitted by the authors in English. 相似文献
545.
黄芩甙是唇形科植物黄芩根(Scutellariax Ridix)的主要成分、有抑菌、抗炎抗变态反应等药理作用。近来就黄芩甙对脂质对氧化的影响和对高脂血症治疗等方面的研究也取得进展。超氧化物歧化酶(SOD)是有歧化超氧负离子(O_2)保护生物机体的功能、是治疗类风湿关节炎等病的医用酶,但由于提取困难、稳定性差,故人们正致力于合成其代用品的探讨。我们所合成的两个新的黄芩甙铜配合物不仅显示一定的SOD样活性,而且也为深入认识中草药的作用机制及开发利用提供了启示。 相似文献
546.
Prabhakar Tirumani S. Venu G. Sridhar M. Praveen kumar A. V. Rajashekhar 《Natural product research》2018,32(11):1295-1298
Hemidesmus indicus (L.) R. Br. was extensively used as hypoglycaemic agent and significance of this plant on secondary complications of diabetes remained unknown. The present study was to investigate the anti-cataractous activity of H. indicus against streptozotocin (STZ)-induced diabetic cataract in rodent model. Root extracts have been prepared and tested for inhibition of rat lens aldose reductase (AR) activity. In addition, its pharmacological potential has been investigated in STZ-induced diabetic cataract. Methanol extract of H. indicus-inhibited AR activity in vitro decreased the blood glucose levels, inhibited the AR activity and delayed the onset and progression of cataract in a dose-dependent manner in in vivo and the antioxidant markers have been normalised. Our results demonstrate that H. indicus has decrease the osmotic stress by inhibiting the AR activity and prevented the loss of antioxidants and delayed the progression of diabetic cataract in STZ-induced diabetic rats. 相似文献
547.
《Acta Crystallographica. Section C, Structural Chemistry》2018,74(4):487-503
Nine salts of the antifolate drugs trimethoprim and pyrimethamine, namely, trimethoprimium [or 2,4‐diamino‐5‐(3,4,5‐trimethoxybenzyl)pyrimidin‐1‐ium] 2,5‐dichlorothiophene‐3‐carboxylate monohydrate (TMPDCTPC, 1:1), C14H19N4O3+·C5HCl2O2S−, ( I ), trimethoprimium 3‐bromothiophene‐2‐carboxylate monohydrate, (TMPBTPC, 1:1:1), C14H19N4O3+·C5H2BrO2S−·H2O, ( II ), trimethoprimium 3‐chlorothiophene‐2‐carboxylate monohydrate (TMPCTPC, 1:1:1), C14H19N4O3+·C5H2ClO2S−·H2O, ( III ), trimethoprimium 5‐methylthiophene‐2‐carboxylate monohydrate (TMPMTPC, 1:1:1), C14H19N4O3+·C6H5O2S−·H2O, ( IV ), trimethoprimium anthracene‐9‐carboxylate sesquihydrate (TMPAC, 2:2:3), C14H19N4O3+·C15H9O2−·1.5H2O, ( V ), pyrimethaminium [or 2,4‐diamino‐5‐(4‐chlorophenyl)‐6‐ethylpyrimidin‐1‐ium] 2,5‐dichlorothiophene‐3‐carboxylate (PMNDCTPC, 1:1), C12H14ClN4+·C5HCl2O2S−, ( VI ), pyrimethaminium 5‐bromothiophene‐2‐carboxylate (PMNBTPC, 1:1), C12H14ClN4+·C5H2BrO2S−, ( VII ), pyrimethaminium anthracene‐9‐carboxylate ethanol monosolvate monohydrate (PMNAC, 1:1:1:1), C12H14ClN4+·C15H9O2−·C2H5OH·H2O, ( VIII ), and bis(pyrimethaminium) naphthalene‐1,5‐disulfonate (PMNNSA, 2:1), 2C12H14ClN4+·C10H6O6S22−, ( IX ), have been prepared and characterized by single‐crystal X‐ray diffraction. In all the crystal structures, the pyrimidine N1 atom is protonated. In salts ( I )–( III ) and ( VI )–( IX ), the 2‐aminopyrimidinium cation interacts with the corresponding anion via a pair of N—H…O hydrogen bonds, generating the robust R22(8) supramolecular heterosynthon. In salt ( IV ), instead of forming the R22(8) heterosynthon, the carboxylate group bridges two pyrimidinium cations via N—H…O hydrogen bonds. In salt ( V ), one of the carboxylate O atoms bridges the N1—H group and a 2‐amino H atom of the pyrimidinium cation to form a smaller R21(6) ring instead of the R22(8) ring. In salt ( IX ), the sulfonate O atoms mimic the role of carboxylate O atoms in forming an R22(8) ring motif. In salts ( II )–( IX ), the pyrimidinium cation forms base pairs via a pair of N—H…N hydrogen bonds, generating a ring motif [R22(8) homosynthon]. Compounds ( II ) and ( III ) are isomorphous. The quadruple DDAA (D = hydrogen‐bond donor and A = hydrogen‐bond acceptor) array is observed in ( I ). In salts ( II )–( IV ) and ( VI )–( IX ), quadruple DADA arrays are present. In salts ( VI ) and ( VII ), both DADA and DDAA arrays co‐exist. The crystal structures are further stabilized by π–π stacking interactions [in ( I ), ( V ) and ( VII )–( IX )], C—H…π interactions [in ( IV )–( V ) and ( VII )–( IX )], C—Br…π interactions [in ( II )] and C—Cl…π interactions [in ( I ), ( III ) and ( VI )]. Cl…O and Cl…Cl halogen‐bond interactions are present in ( I ) and ( VI ), with distances and angles of 3.0020 (18) and 3.5159 (16) Å, and 165.56 (10) and 154.81 (11)°, respectively. 相似文献
548.
549.
配合物[Ni(EDTB)]•2Cl•CH3OH•C2H5OH的合成、晶体结构及SOD模拟活性的研究 总被引:3,自引:0,他引:3
报道六齿配体N,N,N',N'-四(2-苯并咪唑亚甲基)-1,2-乙二胺(EDTB)及单核镍(II)配合物[Ni(EDTB)]•2Cl• CH3OH•C2H5OH的合成、晶体结构和SOD模拟活性. 该配合物为三斜晶系, P1空间群, a=1.0931(2) nm, b=1.1693(2) nm, c=1.6756(4) nm, α=76.042(3)°, β=88.787(3)°, γ=72.044(3)°, V=1.9740(7) nm3, Dc=1.321 g/cm3, Z=2, F(000)=824, μ=0.670 mm-1. 最终因子R[I>2σ(I)]: R1=0.0611, wR2=0.1497; R(全部数据): R1=0.0870, wR2=0.1604. 结构分析表明, 镍(II)分别与配体中的四个苯并咪唑氮和两个亚胺基氮配位形成扭曲的八面体构型. 改良的邻苯三酚自氧化活性测定表明, 该配合物具有较高的SOD模拟活性. 相似文献
550.
The effect of changing the amount of externally added cobalt(Ⅱ) serine, an organic metal compound, and the pH value of the enzyme solution on the interaction of copper zinc superoxide dismutase (Cu 2Zn 2SOD) with cobalt(Ⅱ) serine was studied by means of visible spectroscopy, inductively coupled plasma atomic emission spectrometry and measurement of enzyme activity. It was found that in aqueous solution, there exists a direct interaction of the metal ions of the active center in Cu 2Zn 2SOD with cobalt(Ⅱ) serine. As a result, part of the metal ions in the metalloenzyme were replaced by Co ion to form Co(Ⅱ) substituted derivatives of SOD and the catalytic activity of the enzyme decreased. 相似文献