全文获取类型
收费全文 | 4963篇 |
免费 | 547篇 |
国内免费 | 3篇 |
出版年
2022年 | 51篇 |
2021年 | 113篇 |
2020年 | 72篇 |
2019年 | 71篇 |
2018年 | 109篇 |
2017年 | 91篇 |
2016年 | 180篇 |
2015年 | 227篇 |
2014年 | 237篇 |
2013年 | 312篇 |
2012年 | 332篇 |
2011年 | 329篇 |
2010年 | 200篇 |
2009年 | 166篇 |
2008年 | 249篇 |
2007年 | 253篇 |
2006年 | 189篇 |
2005年 | 197篇 |
2004年 | 180篇 |
2003年 | 180篇 |
2002年 | 159篇 |
2001年 | 96篇 |
2000年 | 106篇 |
1999年 | 85篇 |
1998年 | 55篇 |
1997年 | 65篇 |
1996年 | 55篇 |
1995年 | 50篇 |
1994年 | 29篇 |
1993年 | 48篇 |
1992年 | 65篇 |
1991年 | 51篇 |
1990年 | 52篇 |
1989年 | 63篇 |
1988年 | 37篇 |
1987年 | 30篇 |
1986年 | 45篇 |
1985年 | 41篇 |
1984年 | 55篇 |
1983年 | 28篇 |
1982年 | 34篇 |
1981年 | 27篇 |
1980年 | 33篇 |
1979年 | 31篇 |
1977年 | 38篇 |
1976年 | 25篇 |
1974年 | 26篇 |
1973年 | 30篇 |
1972年 | 27篇 |
1970年 | 35篇 |
排序方式: 共有5513条查询结果,搜索用时 15 毫秒
11.
12.
13.
Thomas Bell Michael B. Bonsall Angus Buckling Andrew S. Whiteley Timothy Goodall Robert I. Griffiths 《Biology letters》2010,6(5):639-642
Productivity and predation are thought to be crucial drivers of bacterial diversity. We tested how the productivity–diversity of a natural bacterial community is modified by the presence of protist predators with different feeding preferences. In the absence of predators, there was a unimodal relationship between bacterial diversity and productivity. We found that three protist species (Bodo, Spumella and Cyclidium) had widely divergent effects on bacterial diversity across the productivity gradient. Bodo and Cyclidium had little effect on the shape of the productivity–diversity gradient, while Spumella flattened the relationship. We explain these results in terms of the feeding preferences of these predators. 相似文献
14.
Dilwyn J. Griffiths 《The Botanical review》2006,72(4):330-366
The major ultrastructural and pigment characteristics of three chlorophyllb-containing photosynthetic prokaryote genera,Prochloron, Prochlorothrix, andProchlorococcus, are summarized. Aspects of their ecology are reviewed, as are also the major findings of comparisons among the three genera,
and between them and the cyanobacteria, based on analyses of nucleotide sequences. The information summarized is discussed
to assess how closely the three genera are related and whether they form a natural taxonomic grouping within the cyanobacteria.
It is concluded that, although much of the evidence points to substantial differences among the three genera, the convenience
of keeping them together as a group, namely, Oxychlorobacteria (formerly Prochlorophyta), outweighs certain inconsistencies
revealed by analysis of a range of objective criteria. Current views on the possible significance of the group to considerations
of the evolution of green chloroplasts are also presented. 相似文献
15.
16.
Kate Jolly 《BMJ (Clinical research ed.)》1991,303(6804):716-717
17.
Controlled generation of reactive oxygen species orchestrates numerous physiological signaling events (Finkel, T. (2011) Signal transduction by reactive oxygen species. J. Cell Biol. 194, 7–15). A major cellular target of reactive oxygen species is the thiol side chain (RSH) of Cys, which may assume a wide range of oxidation states (i.e. −2 to +4). Within this context, Cys sulfenic (Cys-SOH) and sulfinic (Cys-SO2H) acids have emerged as important mechanisms for regulation of protein function. Although this area has been under investigation for over a decade, the scope and biological role of sulfenic/sulfinic acid modifications have been recently expanded with the introduction of new tools for monitoring cysteine oxidation in vitro and directly in cells. This minireview discusses selected recent examples of protein sulfenylation and sulfinylation from the literature, highlighting the role of these post-translational modifications in cell signaling. 相似文献
18.
19.
20.