全文获取类型
收费全文 | 701432篇 |
免费 | 74520篇 |
国内免费 | 366篇 |
出版年
2018年 | 5886篇 |
2016年 | 7816篇 |
2015年 | 10541篇 |
2014年 | 12467篇 |
2013年 | 18220篇 |
2012年 | 20089篇 |
2011年 | 20470篇 |
2010年 | 13946篇 |
2009年 | 12754篇 |
2008年 | 18251篇 |
2007年 | 19287篇 |
2006年 | 18005篇 |
2005年 | 17304篇 |
2004年 | 17068篇 |
2003年 | 16624篇 |
2002年 | 16392篇 |
2001年 | 32244篇 |
2000年 | 32459篇 |
1999年 | 25595篇 |
1998年 | 8532篇 |
1997年 | 9046篇 |
1996年 | 8600篇 |
1995年 | 8072篇 |
1994年 | 7943篇 |
1993年 | 7776篇 |
1992年 | 21811篇 |
1991年 | 21316篇 |
1990年 | 20895篇 |
1989年 | 20337篇 |
1988年 | 19027篇 |
1987年 | 17862篇 |
1986年 | 16614篇 |
1985年 | 16875篇 |
1984年 | 13841篇 |
1983年 | 11960篇 |
1982年 | 9055篇 |
1981年 | 8079篇 |
1980年 | 7552篇 |
1979年 | 13263篇 |
1978年 | 10235篇 |
1977年 | 9427篇 |
1976年 | 8822篇 |
1975年 | 9808篇 |
1974年 | 10535篇 |
1973年 | 10365篇 |
1972年 | 9582篇 |
1971年 | 8539篇 |
1970年 | 7517篇 |
1969年 | 7340篇 |
1968年 | 6763篇 |
排序方式: 共有10000条查询结果,搜索用时 619 毫秒
171.
172.
—A resolution of the enhancement of protein synthesis in the visual cortex of rats during first exposure to light (Richardson and Rose , 1972) was achieved by polyacrylamide gel electrophoresis using a double-labelling technique. Differential incorporation of lysine was established between exposed and control animals in two fractions of the soluble proteins and seven fractions of the insoluble proteins. This suggests that exposure to a new experience of this type involves a specific effect on protein synthesis, rather than a general stimulation across all fractions. 相似文献
173.
174.
175.
176.
177.
178.
179.
E Giannazzo F Licata G Li Volsi G Mio F Santangelo M Scivoli 《Bollettino della Società italiana di biologia sperimentale》1992,68(11):677-683
A computer-assisted analysis of the spatial distribution of neurons having homogeneous characteristics is described in this paper. The camera lucida drawings of sections of a brain nucleus and the points representing the neurons labeled on the basis of a specific behavior of discharge rates were digitized on a personal computer Amiga 2000 or IBM compatible. Our software provided: a) the computerized, stereotaxically oriented reconstruction of the stored sections and of the plotted neurons; b) the identification within each section of the mass center (MC) of the units sharing a given behavior and of the area where the density of such neurons was maximal (MDA). The routine was tested on the spatial distribution of neuronal responses to serotonin in the lateral vestibular nucleus. 相似文献
180.
G. Rai M. Stamenkovi-Radak T. Savi M. Andjelkovi 《Journal of Zoological Systematics and Evolutionary Research》2008,46(1):31-37
The adaptive significance of inversion polymorphism of Drosophila subobscura is well established. However, little is known about gene combinations within inversions which are coadapted because of population-specific effects. We studied this aspect of Dobzhansky's coadaptation hypothesis, using the systematic inbreeding method. Differences in magnitude and quality of inversion polymorphism in two ecologically and topologically distinct habitats were compared after several generations of continuous full-sib inbreeding. Populations from the two habitats differ in frequency of homokaryotypes after third and fifth generation of inbreeding and in the levels of homozygosity of different gene arrangements. The effect of homozygosity appears population and chromosome specific. 相似文献