全文获取类型
收费全文 | 291篇 |
免费 | 0篇 |
专业分类
系统科学 | 10篇 |
理论与方法论 | 1篇 |
现状及发展 | 77篇 |
研究方法 | 23篇 |
综合类 | 166篇 |
自然研究 | 14篇 |
出版年
2022年 | 1篇 |
2018年 | 4篇 |
2016年 | 1篇 |
2014年 | 2篇 |
2013年 | 3篇 |
2012年 | 6篇 |
2011年 | 29篇 |
2010年 | 2篇 |
2009年 | 3篇 |
2008年 | 11篇 |
2007年 | 12篇 |
2006年 | 9篇 |
2005年 | 11篇 |
2004年 | 7篇 |
2003年 | 13篇 |
2002年 | 13篇 |
2001年 | 13篇 |
2000年 | 13篇 |
1999年 | 7篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 6篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 7篇 |
1982年 | 1篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 8篇 |
1978年 | 4篇 |
1977年 | 6篇 |
1976年 | 10篇 |
1975年 | 7篇 |
1974年 | 5篇 |
1973年 | 6篇 |
1972年 | 3篇 |
1971年 | 9篇 |
1970年 | 9篇 |
1969年 | 2篇 |
1968年 | 5篇 |
1967年 | 6篇 |
1966年 | 6篇 |
1965年 | 3篇 |
1963年 | 1篇 |
1948年 | 1篇 |
排序方式: 共有291条查询结果,搜索用时 15 毫秒
41.
Summary Male Sprague-Dawley rats injected with 2.0 g/kg of ethanol and analyzed 1 h later at 8 specific times of the day showed diurnal rhythms for alcohol concentrations in the blood, urine, brain and liver tissues. The circadian fluctuation noted for the concentrations of blood and tissue ethanol might indicate a diurnal variation in the enzymatic metabolism of ethanol.Supported by a grant from the US National Aeronautics and Space Administration. 相似文献
42.
DNA homology of two Mycoplasma species 总被引:2,自引:0,他引:2
R T Walker 《Nature》1967,216(5116):711-712
43.
44.
Effect of thiocyanate on nitrosation of amines 总被引:2,自引:0,他引:2
45.
Clayton DG Walker NM Smyth DJ Pask R Cooper JD Maier LM Smink LJ Lam AC Ovington NR Stevens HE Nutland S Howson JM Faham M Moorhead M Jones HB Falkowski M Hardenbol P Willis TD Todd JA 《Nature genetics》2005,37(11):1243-1246
The main problems in drawing causal inferences from epidemiological case-control studies are confounding by unmeasured extraneous factors, selection bias and differential misclassification of exposure. In genetics the first of these, in the form of population structure, has dominated recent debate. Population structure explained part of the significant +11.2% inflation of test statistics we observed in an analysis of 6,322 nonsynonymous SNPs in 816 cases of type 1 diabetes and 877 population-based controls from Great Britain. The remainder of the inflation resulted from differential bias in genotype scoring between case and control DNA samples, which originated from two laboratories, causing false-positive associations. To avoid excluding SNPs and losing valuable information, we extended the genomic control method by applying a variable downweighting to each SNP. 相似文献
46.
Sinkins SP Walker T Lynd AR Steven AR Makepeace BL Godfray HC Parkhill J 《Nature》2005,436(7048):257-260
Wolbachia is a common maternally inherited bacterial symbiont able to induce crossing sterilities known as cytoplasmic incompatibility (CI) in insects. Wolbachia-modified sperm are unable to complete fertilization of uninfected ova, but a rescue function allows infected eggs to develop normally. By providing a reproductive advantage to infected females, Wolbachia can rapidly invade uninfected populations, and this could provide a mechanism for driving transgenes through pest populations. CI can also occur between Wolbachia-infected populations and is usually associated with the presence of different Wolbachia strains. In the Culex pipiens mosquito group (including the filariasis vector C. quinquefasciatus) a very unusual degree of complexity of Wolbachia-induced crossing-types has been reported, with partial or complete CI that can be unidirectional or bidirectional, yet no Wolbachia strain variation was found. Here we show variation between incompatible Culex strains in two Wolbachia ankyrin repeat-encoding genes associated with a prophage region, one of which is sex-specifically expressed in some strains, and also a direct effect of the host nuclear genome on CI rescue. 相似文献
47.
Summary Adenyl cyclase activity in isolated mouse liver cell membranes was stimulated two-fold by endotoxin. Furthermore, endotoxin inhibited epinephrine induction of adenyl cyclase activity, apparently through interruption of the phospholipid moiety of the enzyme complex. 相似文献
48.
49.
50.