全文获取类型
收费全文 | 1524篇 |
免费 | 75篇 |
出版年
2022年 | 10篇 |
2021年 | 21篇 |
2020年 | 15篇 |
2019年 | 17篇 |
2018年 | 24篇 |
2017年 | 28篇 |
2016年 | 28篇 |
2015年 | 43篇 |
2014年 | 53篇 |
2013年 | 75篇 |
2012年 | 105篇 |
2011年 | 81篇 |
2010年 | 61篇 |
2009年 | 35篇 |
2008年 | 58篇 |
2007年 | 68篇 |
2006年 | 59篇 |
2005年 | 52篇 |
2004年 | 40篇 |
2003年 | 42篇 |
2002年 | 37篇 |
2001年 | 49篇 |
2000年 | 40篇 |
1999年 | 41篇 |
1998年 | 18篇 |
1997年 | 17篇 |
1996年 | 13篇 |
1995年 | 18篇 |
1994年 | 18篇 |
1993年 | 10篇 |
1992年 | 25篇 |
1991年 | 38篇 |
1990年 | 34篇 |
1989年 | 29篇 |
1988年 | 31篇 |
1987年 | 26篇 |
1986年 | 15篇 |
1985年 | 12篇 |
1984年 | 12篇 |
1983年 | 12篇 |
1981年 | 13篇 |
1980年 | 10篇 |
1979年 | 19篇 |
1978年 | 12篇 |
1974年 | 9篇 |
1973年 | 15篇 |
1972年 | 11篇 |
1971年 | 15篇 |
1970年 | 13篇 |
1969年 | 14篇 |
排序方式: 共有1599条查询结果,搜索用时 15 毫秒
931.
932.
933.
Synthesis, mass spectral characterization and immunoadjuvant activity of some novel lipophilic derivatives of muramyl dipeptides 总被引:1,自引:0,他引:1
R K Jain C M Gupta R K Saxena R P Saxena K C Saxena R Shukla N Anand C E Costello 《Chemistry and physics of lipids》1986,41(3-4):237-264
Some novel lipophilic derivatives of N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP) have been prepared and rigorously evaluated by spectroscopic means. Fast atom bombardment and field desorption mass spectrometry provided information about both molecular weight and structural detail. The new MDP derivatives have been tested in guinea pigs for immunoadjuvant activity using egg albumin as the model antigen. Amongst these derivatives, 6-O-[3-(5-cholesten-3 beta-yloxycarbonyl) propionyl]-N-acetylmuramyl-L-alanyl-D-isoglutamine (CSMDP), 6-O-[3-1,2-dipalmitoyl-sn-glycero-3-carbonyl) propionyl]-N-acetylmuramyl-L-alanyl-D-isoglutamine (GSMDP) and N-palmitoyl muramyl-L-alanyl-D-isoglutamine (PMDP) possessed significantly better activity than MDP, as judged by the antigen-specific antibody and delayed hypersensitivity responses in the immunized animals. In addition, CSMDP was found to induce strong delayed hypersensitivity response even in saline. These three active compounds were also tested for their pyrogenic response in rabbits, and were found to be lesser pyrogenic than MDP. Some of these MDP derivatives hold promise as adjuvants in immunization. 相似文献
934.
935.
Calcium was the most important of 27 environmental components affecting density for a 50 week period. Simultaneous stepwise regression accounted for more variability in total number/1 and in the number of ovigerous females/1 than did any of the lag analyses; 1-week lag accounted for the greatest amount of variability in clutch size. Total number and clutch size were little affected by measures of food.Contribution no. 93 Kansas Water Resources Research Institute, Manhatten Kansas. The U.S. Department of Interior, Office of Water Resources Research provided partial support. 相似文献
936.
The G-protein coupled receptor (GPCR) superfamily is one of the largest classes of molecules involved in signal transduction across the plasma membrane. The serotonin(1A) receptor is a representative member of the GPCR superfamily and serves as an important target in the development of therapeutic agents for neuropsychiatric disorders such as anxiety and depression. In the context of the pharmacological relevance of the serotonin(1A) receptor, the membrane organization and dynamics of this receptor in the cellular environment assume relevance. We have highlighted results, obtained from fluorescence microscopy-based approaches, related to domain organization and dynamics of the serotonin(1A) receptor. A fraction of serotonin(1A) receptors displays detergent insolubility, monitored using green fluorescent protein, that increases upon depletion of membrane cholesterol. Fluorescence recovery after photobleaching measurements with varying bleach spot sizes show that lateral diffusion parameters of serotonin(1A) receptors in normal cells are consistent with models describing diffusion of molecules in a homogenous membrane. Interestingly, these characteristics are altered in cholesterol-depleted cells. Taken together, we conclude that the serotonin(1A) receptor exhibits dynamic confinement in the cellular plasma membranes. Progress in understanding GPCR organization and dynamics would result in better insight into our overall understanding of GPCR function in health and disease. 相似文献
937.
938.
Kamal A Srikanth YV Naseer Ahmed Khan M Ashraf M Kashi Reddy M Sultana F Kaur T Chashoo G Suri N Sehar I Wani ZA Saxena A Sharma PR Bhushan S Mondhe DM Saxena AK 《Bioorganic & medicinal chemistry》2011,19(23):7136-7150
A series of N-(2-anilino-pyridyl) linked 2-amino benzothiazoles (4a-n) and [1,2,4]triazolo [1,5-b]benzothiadiazine conjugates (5a-j) have been designed, synthesized and evaluated for their antiproliferative activity. Some of these compounds (4h-k, 4n, and 5e) have exhibited potent cytotoxicity specifically against human leukemia HL-60 cell lines with IC(50) values in the range of 0.08-0.70 μM. All these compounds were tested for their effects on the cell cycle perturbations and induction of apoptosis. Morphological evidences of apoptosis, including fragmentation of nuclei and inter nucleosomal DNA laddering formation were clearly observed after 24h exposure to compound 4i. Flow cytometry analysis revealed that compound 4i showed drastic cell cycle perturbations due to concentration dependant increase in the sub-G0 region which comprises of both the apoptotic and debris fraction, thus implying the extent of cell death. These compounds trigger the mitochondrial apoptotic pathway that results in the loss of mitochondrial membrane potential through activation of multiple caspases followed by activation of caspase-3, and finally cleavage of PARP. Further the mechanism of cell death was analysed by fluorescent microscopic analysis and also by scanning electron microscopy. The cytotoxicity of 4i correlated with induction of apoptosis, caspases activation and DNA damage and thus indicating the apoptotic pathway of anticancer effect of these compounds. 相似文献
939.
940.