首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   4301篇
  免费   68篇
  国内免费   16篇
  4385篇
  2024年   63篇
  2023年   92篇
  2022年   243篇
  2021年   360篇
  2020年   175篇
  2019年   197篇
  2018年   259篇
  2017年   157篇
  2016年   236篇
  2015年   289篇
  2014年   302篇
  2013年   326篇
  2012年   318篇
  2011年   276篇
  2010年   169篇
  2009年   155篇
  2008年   150篇
  2007年   134篇
  2006年   98篇
  2005年   84篇
  2004年   51篇
  2003年   52篇
  2002年   33篇
  2001年   13篇
  2000年   9篇
  1999年   10篇
  1998年   11篇
  1997年   9篇
  1996年   9篇
  1995年   9篇
  1994年   7篇
  1993年   9篇
  1992年   10篇
  1991年   4篇
  1989年   7篇
  1988年   3篇
  1987年   6篇
  1986年   7篇
  1985年   7篇
  1984年   6篇
  1983年   2篇
  1982年   6篇
  1981年   3篇
  1980年   2篇
  1979年   3篇
  1978年   3篇
  1974年   3篇
  1971年   1篇
  1968年   1篇
  1967年   1篇
排序方式: 共有4385条查询结果,搜索用时 0 毫秒
1.
2.
Biosurfactant production by Pseudomonas aeruginosa EBN-8 mutant was studied in shake flasks on separate wastes from canola, soybean and corn oil refineries. Of the substrates tested, canola oil refinery waste (COD=20 g l−1) supplemented with sodium nitrate (at COD/N=20) showed the best microbial growth (4.50 g l−1) and rhamnolipid production (8.50 g l−1), at 10 d of incubation with the specific growth rate of 0.316 h−1 and specific product yield of 0.597 g g−1 h. Its cell-free supernatant showed the critical micelle dilution (CMD) of 150 and surface tension (ST) of 28.5 mN m−1.  相似文献   
3.
International Journal of Peptide Research and Therapeutics - Klebsiella oxytoca is a gram-negative bacterium. It is opportunistic in nature and causes hospital acquired infections....  相似文献   
4.
5.
6.
7.
The precise characterization of post translational modifications (PTMs) is important for the understanding of protein regulatory mechanisms and their role in disease. However, experimental studies on PTMs, especially with multifunctional proteins are difficult to follow and investigate. Bioinformatic tools are therefore helpful in predicting key protein modifications. To study the role of PTMs in claudin proteins, specifically claudin-1, -3 and -4 in the onset or progression of human cancers, we performed an in silico study of various PTMs and investigated their interplay. Given that the activity of claudins is known to be influenced by two types of PTMs, specifically palmitoylation and kinase- dependent phosphorylation, we predicted two conserved regions in the topological domains of claudin-1, -3 and -4 as potential palmitoylation sites. Furthermore, conserved phosphorylation residues, which may be targets for kinases and can alter claudin’s ability to maintain the integrity of tight junctions, were identified. To our knowledge, this is the first report to suggest O-glycosylation of claudin proteins, as well as a potential novel interplay between phosphorylation and O-glycosylation at Yin Yang sites. Thus, our findings may facilitate the production of anti-cancer drugs, and suggest that novel therapeutic strategies should target post translational events.  相似文献   
8.
One group of commonly found parasites in birds, for which fitness consequences and effects on life history traits have been much debated are Haemosporidian blood parasites. In a long term study population of great reed warblers Acrocephalus arundinaceus in Sweden, previous studies have shown that the Haemosporidian blood parasites are in their chronic phase during the breeding season and that the fitness of infected and non‐infected birds are similar. In the present study, we quantified parasite intensity (parasitemia) in 718 adults great reed warblers sampled between 1987 and 1998 for the three most common parasite species; Haemoproteus payevskyi (lineage GRW1), Plasmodium ashfordi (GRW2) and Plasmodium relictum (GRW4). We verified that the q‐PCR method is accurately quantifying Haemoproteus payevskyi (GRW1) as it was highly correlated with the number of parasites seen under microscope. Frequency of mixed infections with two lineages was significantly higher than expected based on the prevalence of each of the three parasite lineages. The mean level of parasitemia was significantly different for the three lineages and individual birds had repeatable parasitemia levels between years. Females tended to have a higher parasitemia than males for all three parasite lineages combined. Females with higher GRW1 parasitemia tended to arrive later in spring to their breeding sites. There was a negative correlation between parasitemia and number of fledged offspring for GRW1, and a tendency for a negative correlation between GRW2 parasitemia and the proportion of recruiting offspring. Overall our results demonstrate that chronic Haemosporidian infections can have slight but significant effects on host life history traits, and therefore may act as important selective agents in wild bird populations.  相似文献   
9.
Identification and characterization of the nuclear proteome is important for detailed understanding of multiple signaling events in eukaryotic cells. Toward this goal, we extensively characterized the nuclear proteome of human T leukemia cells by sequential extraction of nuclear proteins with different physicochemical properties using three buffer conditions. This large scale proteomic study also tested the feasibility and technical challenges associated with stable isotope labeling by amino acids in cell culture (SILAC) to uncover quantitative changes during apoptosis. Analyzing proteins from three nuclear fractions extracted from naive and apoptotic cells generated 780,530 MS/MS spectra that were used for database searching using the SEQUEST algorithm. This analysis resulted in the identification and quantification of 1,174 putative nuclear proteins. A number of known nuclear proteins involved in apoptosis as well as novel proteins not known to be part of the nuclear apoptotic machinery were identified and quantified. Consistent with SILAC-based quantifications, immunofluorescence staining of nucleus, mitochondria, and some associated proteins from both organelles revealed a dynamic recruitment of mitochondria into nuclear invaginations during apoptosis.  相似文献   
10.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号