全文获取类型
收费全文 | 10620篇 |
免费 | 922篇 |
国内免费 | 3篇 |
出版年
2023年 | 38篇 |
2022年 | 93篇 |
2021年 | 170篇 |
2020年 | 99篇 |
2019年 | 147篇 |
2018年 | 173篇 |
2017年 | 164篇 |
2016年 | 277篇 |
2015年 | 482篇 |
2014年 | 510篇 |
2013年 | 602篇 |
2012年 | 869篇 |
2011年 | 853篇 |
2010年 | 533篇 |
2009年 | 507篇 |
2008年 | 699篇 |
2007年 | 600篇 |
2006年 | 590篇 |
2005年 | 477篇 |
2004年 | 512篇 |
2003年 | 516篇 |
2002年 | 457篇 |
2001年 | 126篇 |
2000年 | 118篇 |
1999年 | 135篇 |
1998年 | 113篇 |
1997年 | 94篇 |
1996年 | 91篇 |
1995年 | 72篇 |
1994年 | 63篇 |
1993年 | 77篇 |
1992年 | 95篇 |
1991年 | 71篇 |
1990年 | 61篇 |
1989年 | 67篇 |
1988年 | 65篇 |
1987年 | 60篇 |
1986年 | 66篇 |
1985年 | 51篇 |
1984年 | 49篇 |
1983年 | 59篇 |
1982年 | 44篇 |
1981年 | 50篇 |
1980年 | 41篇 |
1979年 | 49篇 |
1978年 | 36篇 |
1977年 | 39篇 |
1974年 | 29篇 |
1973年 | 35篇 |
1971年 | 31篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Amélie Faubert Angela Samaan Jacques Thibodeau 《The Journal of biological chemistry》2002,277(4):2750-2755
In the endocytic pathway of antigen-presenting cells, HLA-DM catalyzes the exchange between class II-associated invariant chain peptide (CLIP) and antigenic peptides onto major histocompatibility complex class II molecules. At low pH of lysosomal compartments, both HLA-DM and HLA-DR undergo conformational changes, and it was recently postulated that two partially exposed tryptophans on HLA-DM might be involved in the interaction between the two molecules. To define contact regions on HLA-DM, we have conducted site-directed mutagenesis on those two hydrophobic residues. The HLA-DM alphaW62A,betaW120A (DM(W62A/W120A)) double mutant was expressed in HLA-DR(+) HeLa cells expressing invariant chain, and the activity of this DM molecule was assessed. Flow cytometry analysis of cell surface DR-CLIP complexes revealed that DM(W62A/W120A) removes CLIP as efficiently as its wild-type counterpart. DM(W62A/W120A) was found in the endocytic pathway by immunofluorescence, and DM-DR complexes were immunoprecipitated from these cells at pH 5. Finally, mutations alphaW62A and betaW120A on HLA-DM did not affect the association with HLA-DO. The complex egresses the endoplasmic reticulum and accumulates in endocytic vesicles. Moreover, DO and DM(W62A/)W120A were co-immunoprecipitated at pH 7. We conclude that the alpha62 and beta120 tryptophan residues are not required for the activity of DM, nor are they directly implicated in the interaction with DR or DO. 相似文献
3.
Summary A male fetus of a pregnancy known to be at risk for X-linked mental retardation with fragile site Xq27 was found to be affected by demonstrating the marker X-chromosome in five of 180 (2.8%) of metaphases derived from amniocytes cultured in medium 199. The results were confirmed in fetal lymphocytes (25 of 86 metaphases, i.e. 29%), and fetal fibroblasts (five of 100 metaphases when cultured in medium 199, and 14 of 100 after exposure to methotrexate for 43 h).This work was supported in part by a research grant from the Deutsche Forschungsgemeinschaft 相似文献
4.
5.
Background
DNA Microarrays have become the standard method for large scale analyses of gene expression and epigenomics. The increasing complexity and inherent noisiness of the generated data makes visual data exploration ever more important. Fast deployment of new methods as well as a combination of predefined, easy to apply methods with programmer's access to the data are important requirements for any analysis framework. Mayday is an open source platform with emphasis on visual data exploration and analysis. Many built-in methods for clustering, machine learning and classification are provided for dissecting complex datasets. Plugins can easily be written to extend Mayday's functionality in a large number of ways. As Java program, Mayday is platform-independent and can be used as Java WebStart application without any installation. Mayday can import data from several file formats, database connectivity is included for efficient data organization. Numerous interactive visualization tools, including box plots, profile plots, principal component plots and a heatmap are available, can be enhanced with metadata and exported as publication quality vector files. 相似文献6.
Kay Terpe 《Applied microbiology and biotechnology》2013,97(24):10243-10254
During the genomics era, the use of thermostable DNA polymerases increased greatly. Many were identified and described—mainly of the genera Thermus, Thermococcus and Pyrococcus. Each polymerase has different features, resulting from origin and genetic modification. However, the rational choice of the adequate polymerase depends on the application itself. This review gives an overview of the most commonly used DNA polymerases used for PCR application: KOD, Pab (Isis?), Pfu, Pst (Deep Vent?), Pwo, Taq, Tbr, Tca, Tfi, Tfl, Tfu, Tgo, Tli (Vent?), Tma (UITma?), Tne, Tth and others. 相似文献
7.
8.
9.
10.