全文获取类型
收费全文 | 1006篇 |
免费 | 2篇 |
国内免费 | 2篇 |
专业分类
系统科学 | 13篇 |
理论与方法论 | 5篇 |
现状及发展 | 259篇 |
研究方法 | 100篇 |
综合类 | 567篇 |
自然研究 | 66篇 |
出版年
2018年 | 4篇 |
2016年 | 4篇 |
2014年 | 3篇 |
2013年 | 8篇 |
2012年 | 31篇 |
2011年 | 98篇 |
2010年 | 6篇 |
2008年 | 39篇 |
2007年 | 37篇 |
2006年 | 36篇 |
2005年 | 37篇 |
2004年 | 34篇 |
2003年 | 31篇 |
2002年 | 34篇 |
2001年 | 20篇 |
2000年 | 44篇 |
1999年 | 16篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 18篇 |
1991年 | 10篇 |
1990年 | 19篇 |
1989年 | 15篇 |
1988年 | 12篇 |
1987年 | 14篇 |
1986年 | 19篇 |
1985年 | 12篇 |
1984年 | 13篇 |
1983年 | 12篇 |
1982年 | 6篇 |
1981年 | 9篇 |
1980年 | 10篇 |
1979年 | 16篇 |
1978年 | 19篇 |
1977年 | 20篇 |
1976年 | 15篇 |
1975年 | 20篇 |
1974年 | 23篇 |
1973年 | 17篇 |
1972年 | 20篇 |
1971年 | 31篇 |
1970年 | 44篇 |
1969年 | 15篇 |
1968年 | 27篇 |
1967年 | 26篇 |
1966年 | 22篇 |
1965年 | 10篇 |
1964年 | 8篇 |
1963年 | 2篇 |
1961年 | 2篇 |
排序方式: 共有1010条查询结果,搜索用时 15 毫秒
131.
A characteristic of growing oocytes of all animal species is the synthesis and accumulation of messenger RNA which is destined to be used primarily by the early embryo. The mechanism(s) which regulates the translation of this maternal mRNA remains unknown. However, the inability of the oocyte to translate all of its putative mRNA has been attributed to at least three limitations: (1) The rate of translation is limited by the availability of components of the translational apparatus other than mRNA, (2) the structural organization of the mRNA prevents translation, and (3) proteins associated with the mRNA prevent translation. Several investigators have suggested that proteins associated with maternal mRNA suppress translation in sea urchin eggs, although others claim that such results may be due to experimental artefacts. Oocyte-specific proteins have been identified in association with non-translating poly(A)+ mRNAs from Xenopus laevis oocytes, and we report here that when these proteins are reconstituted with mRNAs in vitro the translation of the mRNAs in vitro is reversibly repressed. The implication is that these proteins are involved in the regulation of translation of stored maternal mRNAs. 相似文献
132.
133.
134.
135.
136.
137.
138.
F. Goetz J. Bishop F. Halberg R. B. Sothern R. Brunning B. Senske B. Greenberg D. Minors P. Stoney I. D. Smith G. D. Rosen D. Cressey E. Haus M. Apfelbaum 《Cellular and molecular life sciences : CMLS》1976,32(8):1081-1084
Summary Relations among circadian rhythms in serum iron, glucagon and insulin and urinary cyclic AMP excretion differ drastically when diurnally active, nocturnally resting human adults consume all daily food for one week as breakfast only and for another week as dinner only—a finding of interest to diverse fields, e.g., for optimizing certain kinds of therapy or for a better utilization of calories.Supported by grants (No. RR-400 from the General Clinical Research Centers Program of the Division of Research Resources, National Institutes of Health, USPHS and Nos. 5-K6-GM-13, 981 and 1RO1-CA-14445-01) and grant No. 20, Fondation de l'industrie pharmaceutique pour la recherche. 相似文献
139.
W N Kuo J L Williams T Floyd-Jones C F Duggans D L Boone S O Smith R F Copeland 《Experientia》1979,35(8):997-998
Decreased activities of both the inhibitory modulator of adenosine 3':5'-monophosphate (cAMP)-dependent protein kinase (A-PK) as well as the stimulatory modulator of guanosine 3':5'-monophosphate (cGMP)-dependent protein kinase (G-PK) from the mouse cerebellum were noted due to the administration of excessive doses of ethanol, caffeine, and phenobarbital for up to 28 days. The dose-dependent of the inhibition of A-PK or the stimulation of G-PK was observed as a function of the amount of protein kinase modulators in the cerebellum of mice receiving different doses of ethanol. 相似文献
140.
J. Bligh A. Silver M. Bacon C. A. Smith 《Cellular and molecular life sciences : CMLS》1978,34(3):370-371
Summary L-glutamic acid injected in doses of 200–1000 nmoles·kg–1 into the cerebral ventricles of sheep had dose-dependent thermoregulatory effects: an increase in heat production and/or a decrease in respiratory frequency, and a rise in rectal temperature. A dose of 800 nmoles·kg–1 had effects comparable with those of a similar injection of 3 nmoles·kg–1 carbamylcholine.We wish to thank Miss Jill Thexton for invaluable assistance. 相似文献