全文获取类型
收费全文 | 81195篇 |
免费 | 5691篇 |
国内免费 | 10篇 |
出版年
2023年 | 556篇 |
2022年 | 689篇 |
2021年 | 1414篇 |
2020年 | 1129篇 |
2019年 | 1190篇 |
2018年 | 2364篇 |
2017年 | 2169篇 |
2016年 | 2941篇 |
2015年 | 4085篇 |
2014年 | 4147篇 |
2013年 | 5340篇 |
2012年 | 6557篇 |
2011年 | 6064篇 |
2010年 | 3774篇 |
2009年 | 3004篇 |
2008年 | 4545篇 |
2007年 | 4322篇 |
2006年 | 4082篇 |
2005年 | 3454篇 |
2004年 | 3457篇 |
2003年 | 3059篇 |
2002年 | 2859篇 |
2001年 | 1647篇 |
2000年 | 1581篇 |
1999年 | 1273篇 |
1998年 | 643篇 |
1997年 | 454篇 |
1996年 | 451篇 |
1995年 | 426篇 |
1994年 | 338篇 |
1993年 | 350篇 |
1992年 | 651篇 |
1991年 | 567篇 |
1990年 | 492篇 |
1989年 | 492篇 |
1988年 | 477篇 |
1987年 | 425篇 |
1986年 | 399篇 |
1985年 | 408篇 |
1984年 | 406篇 |
1983年 | 277篇 |
1982年 | 273篇 |
1981年 | 208篇 |
1980年 | 214篇 |
1979年 | 244篇 |
1978年 | 243篇 |
1975年 | 220篇 |
1974年 | 239篇 |
1973年 | 241篇 |
1972年 | 208篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
HIF-1 expression in healing wounds: HIF-1alpha induction in primary inflammatory cells by TNF-alpha 总被引:12,自引:0,他引:12
5.
Sebastián Moran Miguel Vizoso Anna Martinez-Cardús Antonio Gomez Xavier Matías-Guiu Sebastián M Chiavenna Andrés G Fernandez Manel Esteller 《Epigenetics》2014,9(6):829-833
A formalin-fixed paraffin-embedded (FFPE) sample usually yields highly degraded DNA, which limits the use of techniques requiring high-quality DNA, such as Infinium Methylation microarrays. To overcome this restriction, we have applied an FFPE restoration procedure consisting of DNA repair and ligation processes in a set of paired fresh-frozen (FF) and FFPE samples. We validated the FFPE results in comparison with matched FF samples, enabling us to use FFPE samples on the Infinium HumanMethylation450 Methylation array. 相似文献
6.
7.
8.
Modern nutritional studies have found that diverse diets are linked to lower infant mortality rates and longer life expectancies in humans. This is primarily because humans require more than fifty essential nutrients for growth and cell maintenance and repair; most of these essential nutrients must come from outside food sources rather than being manufactured by the body itself; and a diversity of food types is required to consume the full suite of essential nutrients necessary for optimal human health. These principles and their related affects on human adaptations and demography are the hallmarks of a theoretical paradigm defined as nutritional ecology. This essay applies concepts derived from nutritional ecology to the study of human evolution. Principles of nutritional ecology are applied to the study of the Middle‐to‐Upper Paleolithic transition in order to broadly illustrate the interpretive ramifications of this approach. At any stage in human evolution, those hominid populations that chose to diversify their subsistence base may have had a selective advantage over competitors who restricted their diet principally to one food type, such as terrestrial mammals. 相似文献
9.
"Pertussis toxin induces tachycardia and impairs the increase in blood pressure produced by alpha 2-adrenergic agonists" 总被引:4,自引:0,他引:4
Administration of purified pertussis toxin to rats induced persistent tachycardia, (observed in conscious rats but not after pithing); as little as 0.05 microgram/100 g produced a significant effect. Pertussis toxin-treatment did not affected the pressor response produced in the pithed rats by the alpha 2-adrenergic agonist methoxamine but markedly diminished the pressor effect of the alpha 2-adrenergic agonists clonidine and azepexole. A role of adenylate cyclase inhibition in the action of postsynaptic vascular alpha 2-adrenergic receptors is suggested. 相似文献
10.