全文获取类型
收费全文 | 368篇 |
免费 | 40篇 |
国内免费 | 1篇 |
出版年
2023年 | 3篇 |
2021年 | 6篇 |
2020年 | 17篇 |
2019年 | 41篇 |
2018年 | 30篇 |
2017年 | 6篇 |
2016年 | 9篇 |
2015年 | 8篇 |
2014年 | 8篇 |
2013年 | 23篇 |
2012年 | 7篇 |
2011年 | 3篇 |
2010年 | 10篇 |
2009年 | 5篇 |
2008年 | 13篇 |
2007年 | 15篇 |
2006年 | 18篇 |
2005年 | 10篇 |
2004年 | 3篇 |
2003年 | 7篇 |
2002年 | 9篇 |
2001年 | 15篇 |
2000年 | 5篇 |
1999年 | 12篇 |
1998年 | 16篇 |
1997年 | 7篇 |
1996年 | 19篇 |
1995年 | 15篇 |
1994年 | 4篇 |
1993年 | 11篇 |
1992年 | 9篇 |
1991年 | 4篇 |
1990年 | 3篇 |
1989年 | 12篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1976年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有409条查询结果,搜索用时 46 毫秒
91.
The Rev axis of HIV autoregulation is one of two critical viral regulatory pathways required for expression of viral genomic and mRNA and for replication. Consequently it is an attractive therapeutic target. Previous studies have investigated the anti-HIV efficacy of targeting to the RRE (the viral RNA target sequence of the Rev axis) a trans-dominant negative inhibitor mutant Rev, M10. In this study we have fused a portion of the influenza virus NS1 protein (which normally inhibits polyA(+) mRNA transport and splicing) to the Rev M10 gene while deleting the NS1 poly(A) binding region. The resulting chimera demonstrates specific and enhanced inhibition of viral-RRE-containing RNA expression. 相似文献
92.
93.
94.
Hari C. Sharma Abdul Rashid War Mandeep Pathania Suraj P Sharma S. MD. Akbar Rajendra S Munghate 《Arthropod-Plant Interactions》2016,10(2):171-181
Global atmospheric concentration of CO2 is likely to increase from 350 to 750 ppm over the next 100 years. The present studies were undertaken to understand the effects of elevated CO2 on enzymatic activity and secondary metabolites in chickpea in relation to expression of resistance to pod borer, Helicoverpa armigera. Fifteen-day-old chickpea plants [ICCL 86111—resistant and JG 11—commercial cultivar] grown in the greenhouse were transferred to open-top chambers (OTC) and kept under 350, 550 and 750 ppm of CO2. Twenty neonates of H. armigera were released on each plant at 7 days after shifting the pots to the OTCs. Un-infested plants were maintained as controls. After 7 days of infestation, the activities of defensive enzymes [peroxidase (POD), polyphenol oxidase (PPO), phenylalanine ammonia lyase (PAL) and tyrosine ammonia lyase (TAL)] and amounts of total phenols and condensed tannins increased with an increase in CO2 concentration in chickpea. The nitrogen balance index was greater in plants kept at 350 ppm CO2 than in plants kept under ambient conditions. The H. armigera-infested plants had higher H2O2 content; amounts of oxalic and malic acids were greater at 750 ppm CO2 than at 350 ppm CO2. Plant damage was greater at 350 ppm than at 550 and 750 ppm CO2. This information will be useful for understanding effects of increased levels of CO2 on expression of resistance to insect pests to develop strategies to mitigate the effects of climate change. 相似文献
95.
Summary Coexistence of peptides in the small intensely fluorescent cells was demonstrated by immunocytochemistry for met-enkephalin-Arg-Gly-Leu, vasoactive intestinal polypeptide, somatostatin, neuropeptide Y and dynorphin. In the extreme example, a single cell was immunoreactive to all 5 peptides examined. Four peptides coexisted in 8% and three peptides in 13% of SIF cells. In 10% of SIF cells no peptide immunoreactivity could be detected. The most prevalent peptide was met-enkephalin (in 46% of cells), then vasoactive intestinal polypeptide (45%), somatostatin (39%), neuropeptide Y (31%) and dynorphin (24%). Met-enkephalin and vasoactive intestinal polypeptide coexisted most commonly (25%). 相似文献
96.
97.
Early and late passage C-6 glial cell growth: Similarities with primary glial cells in culture 总被引:10,自引:0,他引:10
Dimitra Mangoura MD Ph.D Nikos Sakellaridis M.D Ph.D. Jackeline Jones Antonia Vernadakis 《Neurochemical research》1989,14(10):941-947
Earlier studies in our laboratory have shown that C-6 glial cells in culture exhibit astrocytic properties with increasing cell passage. In this study, we tested the responsiveness of early and late passage C-6 glial cells to various cultures conditions: culture substrata (collagen, poly-L-lysine, plastic), or supplements for the culture medium, DMEM, [fetal calf, or heat inactivated (HI) serum, or media conditioned from mouse neuroblastoma cells (NBCM) or primary chick embryo cultured neurons (NCM)]. Glutamine synthetase (GS) and cyclic nucleotide phosphohydrolase (CNP), astrocytic and oligodendrocytic glial markers, were used. Cell numer and protein content increased exponentially with days in culture regardless of the type of the substratum or cell passage. Differences in cell morphology among the three types of substratum were also reflected on GS activity, which rose by three-fold on culture day 3 for cells grown on collagen; thereafter, GS profiles were similar for all substrata. This early rise in GS is interpreted to reflect differential cell adhesion processes on the substrata; specifically, cell adhesion on the collagen stimulated differentiation into astrocytic phenotype.Analogous to immature glia cells in primary cultures, early passage C-6 glial cells responded to neuronal factors supplied either from NCM or NBCM by expressing reduced GS activity, the astrocytic marker and enhanced CNP activity, the oligodendrocytic marker. Thus, early passage cells can be induced to express either astrocytic or oligodendrocytic phenotype. In accordance with our previous reports on primary glial cells, late passage C-6 cells exhibit their usual astrocytic behavior, responding to serum factors with GS activity. Moreover, whereas NCM or NBCM alone markedly lowered GS activity, a combination with serum restored activity. The present findings confirm our previous observations and further establish the C-6 glial cells as a reliable model to study immature glia.Special issue dedicated to Dr. Paola S. Timiras. 相似文献
98.
Yoshimasa Ito Kimie Fukuyama MD PhD Noboru Horie William L. Epstein 《Molecular and cellular biochemistry》1984,60(2):183-188
Summary Enzymatic activity was investigated in metal-binding proteins from rat epidermal cells. Tris-HCl buffer soluble and KSCN solubilized proteins were extracted stepwise from granular and cornified cells of 2-day old rat epidermis. Each extract was separately applied to a Cu2+ or Zn2– chelate Sepharose 6B column and the proteins were eluted with buffers of different pHs and finally with EDTA solution. Metal chelate-binding proteins were found in both soluble and solubilized proteins but there was a larger amount in the latter. Affinity of the proteins to bind with Cu2+ chelate was greater than that with Zn2+ chelate. In Tris-HCl buffer extract, histidase activity was detected in Cu2+ chelate-binding proteins, but not in Zn2+ chelate-binding proteins. Acid phosphatase, cysteine proteinase, dipeptidase, cathepsin D, -galactosidase, gelatin hydrolase, and superoxide dismutase did not bind to metal chelates although these enzymes, except acid phosphatase, were inhibited by Cu2+, but not by Zn2+. In contrast, KSCN solubilized metal chelate-binding proteins showed plasminogen activator, acid phosphatase, and gelatin and casein hydrolases while histone hydrolase did not bind to either chelate column. Since metal-binding proteins in rat epidermal cells have been shown previously to be histidine- and cysteine-rich proteins concentrated in keratohyalin granules, interaction of metals and the structural proteins with certain enzymes may be involved in the regulation of epidermal cell functions. 相似文献
99.
100.