全文获取类型
收费全文 | 490篇 |
免费 | 30篇 |
出版年
2023年 | 3篇 |
2022年 | 2篇 |
2021年 | 6篇 |
2020年 | 10篇 |
2019年 | 5篇 |
2018年 | 12篇 |
2017年 | 7篇 |
2016年 | 9篇 |
2015年 | 19篇 |
2014年 | 21篇 |
2013年 | 19篇 |
2012年 | 27篇 |
2011年 | 33篇 |
2010年 | 23篇 |
2009年 | 23篇 |
2008年 | 25篇 |
2007年 | 23篇 |
2006年 | 24篇 |
2005年 | 24篇 |
2004年 | 20篇 |
2003年 | 26篇 |
2002年 | 20篇 |
2001年 | 15篇 |
2000年 | 14篇 |
1999年 | 5篇 |
1998年 | 8篇 |
1997年 | 8篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 7篇 |
1993年 | 6篇 |
1992年 | 9篇 |
1991年 | 6篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1982年 | 2篇 |
1981年 | 4篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1974年 | 2篇 |
1972年 | 4篇 |
1969年 | 3篇 |
1967年 | 1篇 |
1966年 | 3篇 |
1965年 | 3篇 |
1959年 | 2篇 |
1934年 | 1篇 |
排序方式: 共有520条查询结果,搜索用时 15 毫秒
11.
Changes in the proteins of chickpea during a 12-day germination period are reported using techniques of gel filtration, DEAE-cellulose chromatography, polyacrylamide gel (PAG) electrophoresis and ultracentrifugation. In the ultracentrifuge, the total proteins of dormant seeds resolve into 3 components which have the sedimentation coefficients of 2.2 S, 6.9 S and 10.3 S respectively. On germination, the presence of fractions of lower sedimentation coefficient indicates possible degradation of these components; in the early stages, the degradation rate of the 7 S fraction is higher, while the 10 S fraction is broken down faster in the later stages. Gel filtration experiments indicate the possibility of degradation of high polymer into intermediary products. Increase in the relative mobility of protein components on PAG and elution constant on DEAE-cellulose chromatographs indicates an increase in the net negative charge of the protein fractions. The accumulation of subunits of the proteins is negligible during the germination period. 相似文献
12.
Saponins, isolated from M. butyracea, were assessed for their acute and subacute oral toxicity in albino rats. Acute doses of saponins caused mortalities and LD50 and LD90 values were 330 and 430 mg/kg body wt respectively. Severe diarrhoea, restlessness and histopathological changes were observed in liver and kidney. Diets containing saponins at 0,250,500 and 1000 ppm for 14 weeks did not affect food intake, growth or organ weights, but induced mild histological changes in liver and kidney and altered the serum levels of alkaline phosphatase, blood urea nitrogen, cholesterol and proteins, particularly in female rats. 相似文献
13.
The synthesis of 4-ethenylidene-5α-androstane-3β, 17β-diol () and of 4-ethenylidene-5α-androstane-3,17-dione () is described. Compound is a competitive inhibitor of solubilized bovine microsomal adrenal Δ5-3β-hydroxysteroid dehydrogenase, with Ki =2.7μM, and is converted by the enzyme to the corresponding 3-ketone. Compound shown to irreversibly inactivate the enzyme in a time-dependent manner (). The substrate, dehydroepiandrosterone, protects against inactivation by compound . In contrast, compound is not oxidized at the 3-position by the 3β-(and 17β)-hydroxysteroid dehydrogenase from , but is oxidized at the 17-position. Nevertheless, the 4-ethenylidene-3,17-diketone () causes irreversible time-dependent inactivation () when incubated directly with this bacterial enzyme, acting as an affinity label. 相似文献
14.
Novotnik Breda Nandy Arpita Venkatesan Senthil Velan Radović Jagoš R. Fuente Juan De la Nejadi Siavash Silva Renzo C. Kouris Angela Thangadurai Venkataraman Bryant Steven Karan Kunal Shor Roman Strous Marc Larter Stephen R. 《Reviews in Environmental Science and Biotechnology》2020,19(1):217-240
Reviews in Environmental Science and Bio/Technology - The world’s energy system is still dominated by fossil fuels. While there is a rapid reduction in the cost of renewable energy and the... 相似文献
15.
Kumar Ritesh Khungar Lisha Shimphrui Rinchuila Tiwari Lalit Dev Tripathi Gayatri Sarkar Neelam K. Agarwal Surekha-Katiyar Agarwal Manu Grover Anil 《Journal of plant biochemistry and biotechnology.》2020,29(4):715-732
Journal of Plant Biochemistry and Biotechnology - Caseinolytic protease (Clp)/Hsp100 proteins are members of the AAA+ (ATPase associated with a variety of cellular activities) family of proteins... 相似文献
16.
Gayatri Jayaraman Karikalan Sinha Subodh Kumar Roy Pranita Mandal Pranab Kumar 《Plant Molecular Biology Reporter》2021,39(3):520-545
Plant Molecular Biology Reporter - Polyploidization plays an important role in the genesis of cultivated wheat (hexaploid and tetraploid) from its diploid progenitors. Thus, evolution during... 相似文献
17.
Srinivasan Pugazhendhi Srikanth Santhanam Jayanthi Venkataraman Isabelle Creveaux Balakrishnan S. Ramakrishna 《Gene》2013
Background
Three mutations (two missense and one frameshift) in the NOD2 gene are associated with Crohn's disease (CD) in a proportion of patients with Crohn's disease in North America, Europe and Australia. These three mutations are not found in Indian patients with CD. We undertook new studies to identify polymorphisms in the NOD2 gene in the Indian population and to detect whether any of these were associated with inflammatory bowel disease (IBD) in this population.Methods
Individual exons of the NOD2 gene were amplified by PCR and subjected to denaturing high performance liquid chromatography (DHPLC) to detect heteroduplex formation. All 12 exons of the NOD2 gene were amplified and Sanger-sequenced to detect polymorphisms in the NOD2 gene. 310 patients with CD, 318 patients with ulcerative colitis (UC) and 442 healthy controls (HC) were recruited for association studies. DNA from these participants was evaluated for the identified eight polymorphisms by Sequenom analysis.Results
Heteroduplex formation was noted by DHPLC in exons 2 and 4 of the NOD2 gene. Sequencing of the entire NOD2 gene data revealed eight polymorphisms – rs2067085, rs2066842, rs2066843, rs1861759, rs2111235, rs5743266, rs2076753, and rs5743291 – of which the latter four were described for the first time in Indians. None of these polymorphisms was associated with CD. The SNPs rs2066842 and rs2066843 were in significant linkage disequilibrium. Both SNPs showed a significant association with UC (P = 0.03 and 0.04 respectively; odds ratio 1.44 and 1.41 respectively).Conclusion
Four NOD2 polymorphisms were identified for the first time in the Indian population. Of 8 NOD2 polymorphisms, none were associated with CD but two were weakly associated with UC. NOD2 polymorphisms do not play a major role in CD genesis in India. 相似文献18.
19.
Xiangli Cui Erin E. Witalison Alena P. Chumanevich Alexander A. Chumanevich Deepak Poudyal Venkataraman Subramanian Aaron J. Schetter Curtis C. Harris Paul R. Thompson Lorne J. Hofseth 《PloS one》2013,8(1)
Protein Arginine Deiminases (PADs) catalyze the post-translational conversion of peptidyl-Arginine to peptidyl-Citrulline in a calcium-dependent, irreversible reaction. Evidence is emerging that PADs play a role in carcinogenesis. To determine the cancer-associated functional implications of PADs, we designed a small molecule PAD inhibitor (called Chor-amidine or Cl-amidine), and tested the impact of this drug on the cell cycle. Data derived from experiments in colon cancer cells indicate that Cl-amidine causes a G1 arrest, and that this was p53-dependent. In a separate set of experiments, we found that Cl-amidine caused a significant increase in microRNA-16 (miRNA-16), and that this increase was also p53-dependent. Because miRNA-16 is a putative tumor suppressor miRNA, and others have found that miRNA-16 suppresses proliferation, we hypothesized that the p53-dependent G1 arrest associated with PAD inhibition was, in turn, dependent on miRNA-16 expression. Results are consistent with this hypothesis. As well, we found the G1 arrest is at least in part due to the ability of Cl-amidine-mediated expression of miRNA-16 to suppress its'' G1-associated targets: cyclins D1, D2, D3, E1, and cdk6. Our study sheds light into the mechanisms by which PAD inhibition can protect against or treat colon cancer. 相似文献
20.
Ribozymes are RNA molecules capable of associating with other RNA molecules through base-pairing and catalyzing various reactions involving phosphate group transfer. Of particular interest to us is the well known ribozyme from Tetrahymena thermophila capable of catalyzing RNA splicing in eukaryotic systems, chiefly because of its potential use as a gene therapy agent. In this article we review the progress made towards visualizing the RNA splicing mediated by the Tetrahymena ribozyme in single living mammalian cells with the beta-lactamase reporter system and highlight the development made in imaging RNA splicing with the luciferase reporter system in living animals. 相似文献