全文获取类型
收费全文 | 1037篇 |
免费 | 121篇 |
出版年
2022年 | 10篇 |
2021年 | 23篇 |
2020年 | 12篇 |
2019年 | 23篇 |
2018年 | 29篇 |
2017年 | 18篇 |
2016年 | 30篇 |
2015年 | 53篇 |
2014年 | 40篇 |
2013年 | 54篇 |
2012年 | 61篇 |
2011年 | 55篇 |
2010年 | 51篇 |
2009年 | 37篇 |
2008年 | 54篇 |
2007年 | 53篇 |
2006年 | 53篇 |
2005年 | 43篇 |
2004年 | 49篇 |
2003年 | 33篇 |
2002年 | 31篇 |
2001年 | 26篇 |
2000年 | 11篇 |
1999年 | 19篇 |
1998年 | 15篇 |
1997年 | 15篇 |
1996年 | 12篇 |
1995年 | 15篇 |
1994年 | 9篇 |
1993年 | 9篇 |
1992年 | 13篇 |
1991年 | 10篇 |
1990年 | 22篇 |
1989年 | 8篇 |
1988年 | 8篇 |
1987年 | 16篇 |
1986年 | 5篇 |
1985年 | 10篇 |
1984年 | 14篇 |
1983年 | 12篇 |
1982年 | 8篇 |
1981年 | 5篇 |
1979年 | 9篇 |
1978年 | 6篇 |
1976年 | 6篇 |
1975年 | 7篇 |
1974年 | 6篇 |
1973年 | 8篇 |
1972年 | 4篇 |
1970年 | 5篇 |
排序方式: 共有1158条查询结果,搜索用时 15 毫秒
81.
82.
83.
Increased sequence diversity coverage improves detection of HIV-specific T cell responses 总被引:2,自引:0,他引:2
Frahm N Kaufmann DE Yusim K Muldoon M Kesmir C Linde CH Fischer W Allen TM Li B McMahon BH Faircloth KL Hewitt HS Mackey EW Miura T Khatri A Wolinsky S McMichael A Funkhouser RK Walker BD Brander C Korber BT 《Journal of immunology (Baltimore, Md. : 1950)》2007,179(10):6638-6650
The accurate identification of HIV-specific T cell responses is important for determining the relationship between immune response, viral control, and disease progression. HIV-specific immune responses are usually measured using peptide sets based on consensus sequences, which frequently miss responses to regions where test set and infecting virus differ. In this study, we report the design of a peptide test set with significantly increased coverage of HIV sequence diversity by including alternative amino acids at variable positions during the peptide synthesis step. In an IFN-gamma ELISpot assay, these "toggled" peptides detected HIV-specific CD4(+) and CD8(+) T cell responses of significantly higher breadth and magnitude than matched consensus peptides. The observed increases were explained by a closer match of the toggled peptides to the autologous viral sequence. Toggled peptides therefore afford a cost-effective and significantly more complete view of the host immune response to HIV and are directly applicable to other variable pathogens. 相似文献
84.
85.
Yan HH Mruk DD Lee WM Cheng CY 《BioEssays : news and reviews in molecular, cellular and developmental biology》2007,29(1):36-48
The ectoplasmic specialization (ES) is a testis-specific, actin-based hybrid anchoring and tight junction. It is confined to the interface between Sertoli cells at the blood-testis barrier, known as the basal ES, as well as between Sertoli cells and developing spermatids designated the apical ES. The ES shares features of adherens junctions, tight junctions and focal contacts. By adopting the best features of each junction type, this hybrid nature of ES facilitates the extensive junction-restructuring events in the seminiferous epithelium during spermatogenesis. For instance, the alpha6beta1-integrin-laminin 333 complex, which is usually limited to the cell-matrix interface in other epithelia to facilitate cell movement, is a putative apical ES constituent. Furthermore, JAM-C and CAR, two tight junction integral membrane proteins, are also components of apical ES involving in spermatid orientation. We discuss herein the mechanisms that maintain the cross-talk between ES and blood-testis barrier to facilitate cell movement and orientation in the seminiferous epithelium. 相似文献
86.
Protein composition of human mRNPs spliced in vitro and differential requirements for mRNP protein recruitment 总被引:6,自引:2,他引:4
下载免费PDF全文
![点击此处可从《RNA (New York, N.Y.)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The deposition of proteins onto newly spliced mRNAs has far reaching consequences for their subsequent metabolism. We affinity-purified spliced human mRNPs under physiological conditions from HeLa nuclear extract and present the first comprehensive inventory of their protein composition as determined by mass spectrometry. Several proteins previously not known to be mRNP-associated were detected, including the DEAD-box helicases DDX3, DDX5, and DDX9, and the ELG, hNHN1, BCLAF1, and TRAP150 proteins. The association of some of the newly identified mRNP proteins was shown to be splicing-dependent, but not to require EJC formation. Initial recruitment of EJC proteins to the spliceosome did not require an EJC binding platform at the -20/24 region of the 5' exon. Finally, while recruitment of EJC proteins and stable EJC formation were not dependent on the cap binding complex, several of the newly identified mRNP proteins required the latter for their association with mRNPs. These results provide novel insights into the composition of spliced mRNPs and the requirements for the association of mRNP proteins with the newly spliced mRNA. 相似文献
87.
Joanna Will Andreas Kyas William S. Sheldrick Dirk Wolters 《Journal of biological inorganic chemistry》2007,12(6):883-894
An automated multidimensional protein identification technology, which combines biphasic liquid chromatography with electrospray
ionisation tandem mass spectrometry (MS/MS), was employed to analyse tryptic peptides from Escherichia coli cells treated with the antiproliferation agent [(η6-p-cymene)RuCl2(DMSO)], where DMSO is dimethyl sulfoxide. MS/MS spectra were recorded for molecular ions generated by neutral loss of p-cymene from intensive peptide ions coordinated by the (η6-p-cymene)RuII fragment. Matching of the MS/MS spectra of the ruthenated peptides to spectra of proteins in the E. coli database enabled the identification of five protein targets for [(η6-p-cymene)RuCl2(DMSO)]. One of these is the constitutive cold-shock protein cspC, which regulates the expression of genes encoding stress-response
proteins, and three of the other targets, ppiD, osmY and sucC, are proteins of the latter type. The DNA damage-inducible helicase
dinG was likewise established as a protein target. Aspartate carboxylate functions were identified as the probable Ru binding
sites in cspC, ppiD and dinG, and threonine and lysine side chains in osmY and sucC, respectively.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
88.
89.
90.
The specialization and structure of antagonistic and mutualistic networks of beetles on rainforest canopy trees
下载免费PDF全文
![点击此处可从《Biological journal of the Linnean Society. Linnean Society of London》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Carl W. Wardhaugh Will Edwards Nigel E. Stork 《Biological journal of the Linnean Society. Linnean Society of London》2015,114(2):287-295
Different kinds of species interactions can lead to different structures within ecological networks. Antagonistic interactions (such as between herbivores and host plants) often promote increasing host specificity within a compartmentalized network structure, whereas mutualistic networks (such as pollination networks) are associated with higher levels of generalization and form nested network structures. However, we recently showed that the host specificity of flower‐visiting beetles from three different feeding guilds (herbivores, fungivores, and predators) in an Australian rainforest canopy was equal to that of herbivores on leaves, suggesting that antagonistic herbivores on leaves are no more specialized than flower‐visitors. We therefore set out to test whether similarities in the host specificity of these different assemblages reflect similarities in underlying network structures. As shown before at the species level, mutualistic communities on flowers showed levels of specialization at the network scale similar to those of the antagonistic herbivore community on leaves. However, the network structure differed, with flower‐visiting assemblages displaying a significantly more nested structure than folivores, and folivores displaying a significantly more compartmentalized structure than flower‐visitors. These results, which need further testing in other forest systems, demonstrate that both antagonistic and mutualistic interactions can result in equally high levels of host specialization among beetle assemblages in tropical rainforests. If this is a widespread phenomenon, it may alter our current perceptions of food web dynamics, species diversity patterns, and co‐evolution in tropical rainforests. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 114 , 287–295. 相似文献