全文获取类型
收费全文 | 161820篇 |
免费 | 13027篇 |
国内免费 | 6838篇 |
出版年
2023年 | 1421篇 |
2022年 | 1552篇 |
2021年 | 6208篇 |
2020年 | 4100篇 |
2019年 | 5074篇 |
2018年 | 5434篇 |
2017年 | 4086篇 |
2016年 | 6091篇 |
2015年 | 9107篇 |
2014年 | 10604篇 |
2013年 | 11506篇 |
2012年 | 14078篇 |
2011年 | 12835篇 |
2010年 | 7962篇 |
2009年 | 6971篇 |
2008年 | 8783篇 |
2007年 | 7889篇 |
2006年 | 7087篇 |
2005年 | 5803篇 |
2004年 | 5365篇 |
2003年 | 4696篇 |
2002年 | 4038篇 |
2001年 | 3601篇 |
2000年 | 3339篇 |
1999年 | 3033篇 |
1998年 | 1534篇 |
1997年 | 1589篇 |
1996年 | 1357篇 |
1995年 | 1306篇 |
1994年 | 1244篇 |
1993年 | 957篇 |
1992年 | 1619篇 |
1991年 | 1339篇 |
1990年 | 1075篇 |
1989年 | 1030篇 |
1988年 | 889篇 |
1987年 | 801篇 |
1986年 | 703篇 |
1985年 | 717篇 |
1984年 | 484篇 |
1983年 | 423篇 |
1982年 | 328篇 |
1981年 | 276篇 |
1980年 | 265篇 |
1979年 | 335篇 |
1978年 | 275篇 |
1977年 | 239篇 |
1976年 | 228篇 |
1974年 | 267篇 |
1972年 | 217篇 |
排序方式: 共有10000条查询结果,搜索用时 35 毫秒
31.
32.
Daren Lee Seth Ruffins Queenie Ng Nikhil Sane Steve Anderson Arthur Toga 《BMC bioinformatics》2010,11(1):608
Background
Digital atlases provide a common semantic and spatial coordinate system that can be leveraged to compare, contrast, and correlate data from disparate sources. As the quality and amount of biological data continues to advance and grow, searching, referencing, and comparing this data with a researcher's own data is essential. However, the integration process is cumbersome and time-consuming due to misaligned data, implicitly defined associations, and incompatible data sources. This work addressing these challenges by providing a unified and adaptable environment to accelerate the workflow to gather, align, and analyze the data. 相似文献33.
34.
Plant and Soil - To investigate the effects of polystyrene microplastics (PS-beads) on the soil properties, photosynthesis of Flowering Chinese cabbage, the rhizosphere microbial community and... 相似文献
35.
36.
We isolated a recombinant H9N2 avian influenza virus (AIV) from fresh egret feces in the Ardeidae protection region of the Dongting Lake wetland area in China, and it was designated A/Egret/Hunan/1/2012(H9N2). This is the first report of isolating H9N2 AIV from wild birds in the Dongting Lake wetland. Its eight gene segments are generated by reassortment of gene segments of different AIV subtypes. These results are helpful for understanding the epidemiology and evolution of AIV in wild birds during migration. 相似文献
37.
Murine Cytomegalovirus m02 Gene Family Protects against Natural Killer Cell-Mediated Immune Surveillance 下载免费PDF全文
Sofia A. Oliveira Se-Ho Park Peter Lee Albert Bendelac Thomas E. Shenk 《Journal of virology》2002,76(2):885-894
The murine cytomegalovirus m02 gene family encodes putative type I membrane glycoproteins named m02 through m16. A subset of these genes were fused to an epitope tag and cloned into an expression vector. In transfected and murine cytomegalovirus-infected cells, m02, m04, m05, m06, m07, m09, m10, and m12 localized to cytoplasmic structures near the nucleus, whereas m08 and m13 localized to a filamentous structure surrounding the nucleus. Substitution mutants lacking the m02 gene (SMsubm02) or the entire m02 gene family (SMsubm02-16) grew like their wild-type parent in cultured cells. However, whereas SMsubm02 was as pathogenic as the wild-type virus, SMsubm02-16 was markedly less virulent. SMsubm02-16 produced less infectious virus in most organs compared to wild-type virus in BALB/c and C57BL/6J mice, but it replicated to wild-type levels in the organs of immunodeficient gamma(c)/Rag2 mice, lacking multiple cell types including natural killer cells, and in C57BL/6J mice depleted of natural killer cells. These results argue that one or more members of the m02 gene family antagonize natural killer cell-mediated immune surveillance. 相似文献
38.
39.
40.
The structure, biochemical properties, and immunogenicity of neurofilament peripheral regions are determined by phosphorylation state 总被引:31,自引:0,他引:31
Treatment of freshly isolated, bovine neurofilaments with Escherichia coli alkaline phosphatase removes over 90% of the phosphate groups from serine residues of the Mr 200,000 and 150,000 polypeptide components (NF200 and NF150). Dephosphorylated NF200 and NF150 remain associated with filaments, but migrate in sodium dodecyl sulfate gels with reduced apparent molecular weights. Unusual migration appears to be due to modification at regions of these polypeptides that are peripheral to the neurofilament backbone as defined by limited chymotryptic digestion. Over 90 monoclonal antibodies recognizing epitopes located within the peripheral domain of native NF200 all show reduced affinity for dephosphorylated NF200. A single monoclonal antibody binds within the filament-associated domain of NF200 and its recognition of NF200 is unaffected upon treatment of neurofilaments with phosphatase. Around 50% of our monoclonal antibodies that bind NF150 monospecifically and at epitopes within its peripheral domain have reduced affinities for NF150 from phosphatase-treated filaments, while the remaining 50% bind native and dephosphorylated NF150 equally well. The smallest neurofilament component (NF70) contains few phosphate groups, most of which remain after treatment of neurofilaments with phosphatase. The resulting form of NF70 migrates normally in gels and its recognition by antibodies is unchanged. We conclude that phosphorylation modifies the structure of the two larger neurofilament polypeptides along domains that are peripheral to the filamentous backbone and that these effects are more pronounced for NF200 than for NF150. 相似文献