全文获取类型
收费全文 | 323篇 |
免费 | 15篇 |
国内免费 | 2篇 |
专业分类
340篇 |
出版年
2023年 | 2篇 |
2022年 | 7篇 |
2021年 | 14篇 |
2020年 | 6篇 |
2019年 | 12篇 |
2018年 | 10篇 |
2017年 | 12篇 |
2016年 | 10篇 |
2015年 | 9篇 |
2014年 | 15篇 |
2013年 | 24篇 |
2012年 | 30篇 |
2011年 | 25篇 |
2010年 | 21篇 |
2009年 | 18篇 |
2008年 | 24篇 |
2007年 | 19篇 |
2006年 | 23篇 |
2005年 | 11篇 |
2004年 | 18篇 |
2003年 | 2篇 |
2002年 | 4篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1968年 | 1篇 |
1967年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有340条查询结果,搜索用时 0 毫秒
101.
Kantevari S Patpi SR Sridhar B Yogeeswari P Sriram D 《Bioorganic & medicinal chemistry letters》2011,21(4):1214-1217
A series of novel aryl and thiophenyl tethered dihydro-6H-quinolin-5-ones have been synthesized in very good yields through CeCl3·7H2O-NaI catalyzed one-pot condensation of β-enaminones derived from the respective methyl ketones; 1,3-cyclohexanedione & 5,5-dimethyl-1,3-cyclohexanedione and ammonium acetate refluxing in 2-propanol. Dihydro-6H-quinolin-5-ones 3a-f was further derivatized to the respective hydroxymethyl analogs using proline as an organocatalyst in aqueous media. Among the all 18 compounds screened for in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv (MTB), dihydro-6H-quinolin-5-ones 4e and 4f were found to be most active with MIC 3.13 μg/mL. 相似文献
102.
Novel compounds with significant medicinal properties have gained much interest in therapeutic approaches for treating various inflammatory disorders like arthritis, odema and snake bites and the post-envenom (impregnating with venom) consequences. Inflammation is caused by the increased concentration of secretory Phospholipases A(2) (sPLA(2)s) at the site of envenom. A novel compound Tris(2,4-di-tert-butylphenyl) phosphate (TDTBPP) was isolated from the leaves of Vitex negundo and the crystal structure was reported recently. The acute anti-inflammatory activity of TDTBPP was assessed by Carrageenan-induced rat paw odema method. TDTBPP reduced the raw paw odema volume significantly at the tested doses of 50 mg/kg and 70 mg/kg body weight. Molecular docking studies were carried out with the X-ray crystal structures of Daboia russelli pulchella's (Vipera russelli, Indian Russell's viper) venom sPLA(2) and Human non-pancreatic secretory PLA(2) (Hnps PLA(2)) as targets to illustrate the antiinflammatory and antidote activities of TDTBPP. Docking results showed hydrogen bond (H-bond) interaction with Lys69 residue lying in the anti-coagulant loop of D. russelli's venom PLA(2), which is essential in the catalytic activity of the enzyme and hydrophobic interactions with the residues at the binding site (His48, Asp49). Docking of TDTBPP with Hnps PLA(2) structure showed coordination with calcium ion directly as well as through the catalytically important water molecule (HOH1260) located at the binding site. 相似文献
103.
104.
Manavalan Arulmani Kalaichelvan Aparanjini Kalyanasundaram Vasanthi Perumal Arumugam Manavalan Arivuchelvi P. Thangavelu Kalaichelvan 《World journal of microbiology & biotechnology》2007,23(4):475-481
An extracellular thermostable alkaline protease isolated from Bacillus
laterosporus-AK1 was purified by sephadex G-200 gel filtration and DEAE cellulose ion-exchange chromatography techniques. The purified
protease showed a maximum relative activity of 100% on casein substrate and appeared as a single band on SDS-PAGE with the
molecular mass of 86.29 kDa. The protease was purified to 11.1-folds with a yield of 34.3%. Gelatin zymogram also revealed
a clear hydrolytic zone due to proteolytic activity, which corresponded to the band obtained with SDS-PAGE. The protease enzyme
had on optimum pH of 9.0 and exhibited highest activity at 75°C. The enzyme activity was highly susceptible to the specific
serine protease inhibitor PMSF, suggesting the presence of serine residues at the active sites. Enzyme activity strongly enhanced
by the metal ions Ca2+ and Mg2+ and this enzyme compatible with aril detergent stability retained 75% even 1-h incubation. The purified protease remove bloodstain
completely when used with Wheel detergent. 相似文献
105.
Sriram D Yogeeswari P Dhakla P Senthilkumar P Banerjee D 《Bioorganic & medicinal chemistry letters》2007,17(7):1888-1891
N-Hydroxythiosemicarbazide was prepared by two methods starting from 2,4-dimethoxy benzyl amine and hydroxylamine hydrochloride, which in turn was reacted with various aldehydes and ketones to obtain the titled compounds. Eighteen compounds were tested for their in vitro activity against Mycobacterium tuberculosis H37Rv using the agar dilution method. Compound 10p was found to be the most potent compound (MIC: 0.28 microM) and was 2.5 times more active than standard isoniazid. 相似文献
106.
107.
108.
Functional electrical stimulation is used to restore movement and function of paralyzed muscles by activating skeletal muscle artificially. An accurate and predictive mathematical model can facilitate the design of stimulation patterns that produce the desired force. The present study is a first step in developing a mathematical model for non-isometric muscle contractions. The goals of this study were to: (1) identify how our isometric force model's parameters vary with changes in knee joint angle, (2) identify the best knee flexion angle to parameterize this model, and (3) validate the model by comparing experimental data to predictions in response to a wide range of stimulation frequencies and muscle lengths. Results showed that by parabolically varying one of the free parameters with knee joint angle and fixing the other parameters at the values identified at 40 degrees of knee flexion, the model could predict the force responses to a wide range of stimulation frequencies and patterns at different muscle lengths. This work showed that the current isometric force model is capable of predicting the changes in skeletal muscle force at different muscle lengths. 相似文献
109.
Vialás V Perumal P Gutierrez D Ximénez-Embún P Nombela C Gil C Chaffin WL 《Proteomics》2012,12(14):2331-2339
We used a brief trypsin treatment followed by peptide separation and identification using nano-LC followed by off-line MS/MS to identify the surface proteins on live Candida albicans organisms growing in biofilms and planktonic yeast cells and hyphae. One hundred thirty-one proteins were present in at least two of the three replicates of one condition and distributed in various combinations of the three growth conditions. Both previously reported and new surface proteins were identified and these were distributed between covalently attached proteins and noncovalently attached proteins of the cell wall. 相似文献
110.
The aluminum (III) complex [SalenAl(III)]Cl (1), (Salen=(R,R)-N,N'-bis[5-methyl-3-(4-methylpiperazinyl)-salicylidene]-1,2-diphenylethanediamine) has been synthesized and characterized by elemental analysis, FT-IR, (1)H and (13)C NMR measurements. The interaction of complex (1) with calf thymus (CT) DNA has been studied extensively by experimental techniques. Thermal denaturation study of DNA with (1) revealed the DeltaT(m) of 5+/-0.2 degrees C. Viscosity and steady-state fluorescence measurements showed that the complex cross-links DNA and the metal center is interacting with DNA during the cross-linking. Also, the phenyl ring in the complex may intercalate between the base pairs of the DNA during the cross-linking. Competitive binding study shows that the enhanced emission intensity of ethidium bromide (EB) in the presence of DNA was quenched by the addition of the metal complex indicating that it displaces EB from its binding site in DNA and the apparent binding constant has been estimated to be (2.8+/-0.2)x10(5) M(-1). Further, time-resolved fluorescence experiments confirm the binding of (1) with DNA and its cross-linking nature. Aluminum ions shown to precipitate DNA completely above the pH 6.0, but no such precipitation was observed with complex (1). The DNA-DNA cross-linking mediated by (1) is further confirmed by gel electrophoresis. 相似文献