全文获取类型
收费全文 | 9460篇 |
免费 | 772篇 |
国内免费 | 670篇 |
出版年
2024年 | 18篇 |
2023年 | 113篇 |
2022年 | 263篇 |
2021年 | 497篇 |
2020年 | 338篇 |
2019年 | 395篇 |
2018年 | 434篇 |
2017年 | 281篇 |
2016年 | 404篇 |
2015年 | 591篇 |
2014年 | 669篇 |
2013年 | 670篇 |
2012年 | 862篇 |
2011年 | 794篇 |
2010年 | 445篇 |
2009年 | 395篇 |
2008年 | 476篇 |
2007年 | 379篇 |
2006年 | 354篇 |
2005年 | 303篇 |
2004年 | 238篇 |
2003年 | 186篇 |
2002年 | 182篇 |
2001年 | 183篇 |
2000年 | 155篇 |
1999年 | 172篇 |
1998年 | 78篇 |
1997年 | 84篇 |
1996年 | 75篇 |
1995年 | 89篇 |
1994年 | 86篇 |
1993年 | 59篇 |
1992年 | 87篇 |
1991年 | 77篇 |
1990年 | 68篇 |
1989年 | 44篇 |
1988年 | 55篇 |
1987年 | 36篇 |
1986年 | 42篇 |
1985年 | 53篇 |
1984年 | 26篇 |
1983年 | 17篇 |
1982年 | 21篇 |
1981年 | 11篇 |
1979年 | 11篇 |
1978年 | 14篇 |
1977年 | 10篇 |
1974年 | 11篇 |
1969年 | 5篇 |
1968年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
Pan C Ye M Liu Y Feng S Jiang X Han G Zhu J Zou H 《Journal of proteome research》2006,5(11):3114-3124
Fe3+-immobilized mesoporous molecular sieves MCM-41 with particle size of ca. 600 nm and pore size of ca. 3 nm is synthesized and applied to selectively trap and separate phosphopeptides from tryptic digest of proteins. For the capture of phosphopeptides, typically 10 microL of tryptic digest solution was first diluted to 1 mL by solution of ACN/0.1% TFA (50:50, v/v) and incubated with 10 microL of 0.1% acetic acid dispersed Fe3+-immobilized MCM-41 for 1 h under vibration. Fe3+-immobilized MCM-41 with trapped phosphopeptides was separated by centrifugation. The deposition was first washed with a volume of 300 microL of solution containing 100 mM NaCl in ACN/0.1% TFA (50:50, v/v) and followed by a volume of 300 microL of solution of 0.1% acetic acid to remove nonspecifically bound peptides. The nanoparticles with trapped phosphopeptides are mixed with 2,5-dihydroxybenzoic acid (2,5-DHB) and deposited onto the target for analysis by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). It was found that phosphopeptides from tryptic digest of alpha-casein and beta-casein are effectively and specifically trapped on Fe3+-immobilized MCM-41 with few peptides nonspecifically adsorbed. After the extraction by Fe3+-immobilized MCM-41, the suppression to the detection of phosphopeptides caused by abundant nonphosphopeptides from tryptic digest is effectively eliminated, and the detection of phosphopeptides by MALDI is greatly enhanced with the value of signal-to-noise (S/N) increased by more than an order of magnitude. It is demonstrated that the mechanism of the adsorption of phosphopeptides on Fe3+-immobilized MCM-41 is based on the interaction between the Fe3+ and the phosphate group. Finally, Fe3+-immobilized MCM-41 is applied to extract phosphopeptides from tryptic digest of the lysate of mouse liver for phosphoproteome analysis by nano-LC-MS/MS. 相似文献
992.
Yuelan Yin Chenju Zhang Hui Dong Zhongwei Niu Zhiming Pan Jinlin Huang Xinan Jiao 《Microbiology and immunology》2010,54(4):175-183
Listeria monocytogenes is a food‐borne pathogen able to cause serious disease in human and animals. Listeriolysin O (LLO), a major virulence factor secreted by this bacterium, is a vacuole‐specific lysin that facilitates bacterial entrance into the host cytosol. Thus, LLO plays a key role in the translocation and intracellular spread of L. monocytogenes. To study the effect of LLO on virulence and immunopotency, a LLO‐deficient L. monocytogenes mutant was constructed using a shuttle vector followed by homologous recombination. The mutant strain had lost hemolytic activity, which resulted in an extremely reduced virulence, 5 logs lower than that of the parent strain, yzuLM4, in BALB/c mice. The number of bacteria detected in the spleens and livers of mice infected with the mutant was greatly reduced, and the bacteria were rapidly eliminated by the host. Kinetics studies in this murine model of infection showed that the invasion ability of the mutant strain was much lower than that of the parent strain. Moreover, immunization with the mutant strain conferred protective immunity against listerial infection. In particular, stimulation with Ag85B240‐259, strong specific Th1 type cellular immunity was elicited by vaccination C57BL/6 mice with hly deficient strain delivering Mycobacterium tuberculosis fusion antigen Ag85B‐ESAT‐6 via intravenous inoculation. These results clearly show that highly attenuated LLO‐deficient L. monocytogenes is an attractive vaccine carrier for delivering heterologous antigens. 相似文献
993.
994.
995.
Robert P. Sellers Leslie D. Alexander Victoria A. Johnson Chun-Chieh Lin Jeremiah Savage Ricardo Corral Jason Moss Tim S. Slugocki Erinprit K. Singh Melinda R. Davis Suchitra Ravula Jamie E. Spicer Jenna L. Oelrich Andrea Thornquist Chung-Mao Pan Shelli R. McAlpine 《Bioorganic & medicinal chemistry》2010,18(18):6822-6856
Utilizing the structure–activity relationship we have developed during the synthesis of the first two generations and mechanism of action studies that point to the interaction of these molecules with the key oncogenic protein Hsp90, we report here the design of 32 new Sansalvamide A derivatives and their synthesis. Our new structures, designed from previously reported potent compounds, were tested for cytotoxicity on the HCT116 colon cancer cell line, and their binding to the biological target was analyzed using computational studies involving blind docking of derivatives using Autodock. Further, we show new evidence that our molecules bind directly to Hsp90 and modulate Hsp90’s binding with client proteins. Finally, we demonstrate that we have integrated good ADME properties into a new derivative. 相似文献
996.
997.
998.
潘中伟 《上海生物医学工程》2010,(1):35-36
目的探讨带器妊娠行人工流产术后节育器嵌顿致滞留或残留于宫内患者取出节育器的效果。方法回顾性分析2006年2月~2009年12月期间在永康市计划生育指导站21例患者的临床资料。结果21例在B超引导下,均成功取出。结论对放置IUD的妇女要定期复查,对放置IUD避孕失败的妇女,明确宫腔内是否有IUD,做到早发现,早诊断,及时正确地处理。 相似文献
999.
1000.
A Peng Lin Guang Ce Wang Song Dong Shen Fang Yang Guang Hua Pan 《Journal of phycology》2010,46(4):773-779
Porphyra yezoensis Ueda is an important marine aquaculture crop with single‐layered gametophytic thalli. In this work, the influences of thallus dehydration level, cold‐preservation (freezing) time, and thawing temperature on the photosynthetic recovery of young P. yezoensis thalli were investigated employing an imaging pulse‐amplitude‐modulation (PAM) fluorometer. The results showed that after 40 d of frozen storage when performing thallus thawing under 10°C, the water content of the thalli showed obvious effects on the photosynthetic recovery of the frozen thalli. The thalli with absolute water content (AWC) of 10%–40% manifested obvious superiority compared to the thalli with other AWCs, while the thalli thawed at 20°C showed very high survival rate (93.10%) and no obvious correlation between thallus AWCs and thallus viabilities. These results indicated that inappropriate thallus water content contributed to the cell damage during the freeze‐thaw cycle and that proper thawing temperature is very crucial. Therefore, AWC between 10% and 40% is the suitable thallus water content range for frozen storage, and the thawing process should be as short as possible. However, it is also shown that for short‐term cold storage the Porphyra thallus water content also showed no obvious effect on the photosynthetic recovery of the thalli, and the survival rate was extremely high (100%). These results indicated that freezing time is also a paramount contributor of the cell damage during the freeze‐thaw cycle. Therefore, the frozen nets should be used as soon as time permits. 相似文献