全文获取类型
收费全文 | 4047篇 |
免费 | 464篇 |
国内免费 | 5篇 |
出版年
2021年 | 48篇 |
2020年 | 31篇 |
2019年 | 45篇 |
2018年 | 49篇 |
2017年 | 60篇 |
2016年 | 61篇 |
2015年 | 133篇 |
2014年 | 161篇 |
2013年 | 162篇 |
2012年 | 205篇 |
2011年 | 220篇 |
2010年 | 129篇 |
2009年 | 113篇 |
2008年 | 176篇 |
2007年 | 162篇 |
2006年 | 178篇 |
2005年 | 143篇 |
2004年 | 157篇 |
2003年 | 137篇 |
2002年 | 147篇 |
2001年 | 112篇 |
2000年 | 128篇 |
1999年 | 98篇 |
1998年 | 64篇 |
1997年 | 42篇 |
1996年 | 45篇 |
1995年 | 44篇 |
1994年 | 42篇 |
1992年 | 83篇 |
1991年 | 78篇 |
1990年 | 75篇 |
1989年 | 54篇 |
1988年 | 64篇 |
1987年 | 63篇 |
1986年 | 53篇 |
1985年 | 68篇 |
1984年 | 61篇 |
1983年 | 48篇 |
1982年 | 40篇 |
1981年 | 33篇 |
1980年 | 43篇 |
1979年 | 62篇 |
1978年 | 30篇 |
1977年 | 43篇 |
1976年 | 31篇 |
1975年 | 37篇 |
1974年 | 47篇 |
1973年 | 44篇 |
1971年 | 29篇 |
1967年 | 34篇 |
排序方式: 共有4516条查询结果,搜索用时 203 毫秒
1.
2.
F Stephen Perry 《BMJ (Clinical research ed.)》1998,317(7156):481
3.
Eliot C. Bush Anne E. Clark Chris M. DeBoever Lillian E. Haynes Sidra Hussain Singer Ma Matthew M. McDermott Adam M. Novak John S. Wentworth 《PloS one》2012,7(11)
A significant proportion of enzymes display cooperativity in binding ligand molecules, and such effects have an important impact on metabolic regulation. This is easiest to understand in the case of positive cooperativity. Sharp responses to changes in metabolite concentrations can allow organisms to better respond to environmental changes and maintain metabolic homeostasis. However, despite the fact that negative cooperativity is almost as common as positive, it has been harder to imagine what advantages it provides. Here we use computational models to explore the utility of negative cooperativity in one particular context: that of an inhibitor binding to an enzyme. We identify several factors which may contribute, and show that acting together they can make negative cooperativity advantageous. 相似文献
4.
Olga Maslova Oleg Fedevych Nadiia Shuvalova Olena Deryabina Volodymyr Zhovnir Miroslav Novak Peter Kruzliak 《Cell and tissue banking》2016,17(2):335-339
The need for selection of the optimal material for the manufacturing of cardio-patches can be resolved by the use of cryostored autologous pericardial tissue. This short communication is a concise fragment of a large-scale research and demonstrates only the efficiency of cell culturing before and after pericardial preservation in the low temperature conditions. 相似文献
5.
6.
The direct effects of the inflammatory mediators, histamine (HI) and serotonin (SE), on the glucose metabolism of Hymenolepis diminuta in vitro were studied by analyzing the excretory products from culture media, containing D-1-13C-glucose and various concentrations of HI and/or SE, by 1H-nuclear magnetic resonance (n.m.r.) spectroscopy. The results revealed that HI markedly accelerated the glycolysis process by increasing the amount of lactate production. The increased glycolytic activity was reflected in a concentration-dependent increase in glucose uptake. Excretion of acetate was also stimulated by HI. A low concentration of SE significantly increased succinate, acetate and lactate excretions, whereas a high concentration had little effect on lactate production and significantly decreased succinate and acetate excretions. A combination of HI and SE treatment at a low concentration had no significant effect, but at a high concentration showed an additive effect, with an increase in lactate production, a decrease in succinate production and an increase in glucose uptake. Thus this work confirms that HI and SE directly influence, albeit differently, energy metabolism of the tapeworm H. diminuta. 相似文献
7.
Nataly Mancette Rijensky Netta R. Blondheim Shraga Eilon Barnea Nir Peled Eli Rosenbaum Aron Popovtzer Solomon M. Stemmer Alejandro Livoff Mark Shlapobersky Neta Moskovits Dafna Perry Eitan Rubin Itzhak Haviv Arie Admon 《Molecular & cellular proteomics : MCP》2020,19(8):1360-1374
- Download : Download high-res image (147KB)
- Download : Download full-size image
- •Sufficient tumor tissues are often unavailable large HLA peptidome discovery.
- •Using patient derived xenograft (PDX) tumors can overcome this limitation.
- •The large PDX HLA peptidomes expand significantly those of the original biopsies.
- •The HLA peptidomes of the PDX tumors included many tumor antigens.
8.
Regulatory volume decrease in alveolar macrophages: cation loss is not correlated with changes in membrane recycling 总被引:2,自引:0,他引:2
Alveolar macrophages regain their normal volume after swelling in hypo-osmotic solutions. This process, termed regulatory volume decrease (RVD), is initiated 3-5 minutes after exposure of cells to hypo-osmotic solutions, and by 30 min, near-normal volumes are attained. Volume decrease does not occur at 0 degrees C or in solutions in which Na+ has been replaced by K+, or Cl- by the impermeant anion gluconate. These results, as well as direct measurement of intracellular cations, indicate that decreases in cell volume result primarily from the loss of K+ and Cl- and are similar to RVD in lymphocytes. Kinetic analysis of cation loss, both by directly measuring changes in intracellular cation content and by assaying rubidium efflux, showed that cation loss occurred immediately upon media dilution. The rate of cation loss fit first-order kinetics and preceded both the initiation of volume decrease and the maximum increase in surface receptor number. These results suggest that the cation transporters responsible for RVD are located at the cell surface and that regulation of activity is not dependent on alterations in membrane movement. 相似文献
9.
10.