全文获取类型
收费全文 | 922篇 |
免费 | 117篇 |
国内免费 | 1篇 |
出版年
2022年 | 8篇 |
2021年 | 11篇 |
2018年 | 13篇 |
2017年 | 6篇 |
2016年 | 9篇 |
2015年 | 25篇 |
2014年 | 27篇 |
2013年 | 52篇 |
2012年 | 32篇 |
2011年 | 45篇 |
2010年 | 22篇 |
2009年 | 40篇 |
2008年 | 45篇 |
2007年 | 37篇 |
2006年 | 47篇 |
2005年 | 37篇 |
2004年 | 45篇 |
2003年 | 41篇 |
2002年 | 39篇 |
2001年 | 12篇 |
2000年 | 14篇 |
1999年 | 18篇 |
1998年 | 12篇 |
1997年 | 9篇 |
1996年 | 13篇 |
1995年 | 13篇 |
1994年 | 11篇 |
1993年 | 7篇 |
1992年 | 29篇 |
1991年 | 45篇 |
1990年 | 35篇 |
1989年 | 27篇 |
1988年 | 22篇 |
1987年 | 13篇 |
1986年 | 13篇 |
1985年 | 16篇 |
1984年 | 6篇 |
1983年 | 10篇 |
1982年 | 8篇 |
1981年 | 6篇 |
1980年 | 8篇 |
1979年 | 8篇 |
1978年 | 10篇 |
1977年 | 9篇 |
1976年 | 9篇 |
1975年 | 7篇 |
1974年 | 12篇 |
1973年 | 8篇 |
1970年 | 6篇 |
1969年 | 7篇 |
排序方式: 共有1040条查询结果,搜索用时 62 毫秒
991.
992.
993.
994.
J R McCarrey K C Hsu E M Eddy R R Klevecz J L Bolen 《The Journal of experimental zoology》1987,242(1):107-111
The germ line represents a cell type of unique interest in mammals because it retains complete genotypic totipotency while undergoing significant phenotypic differentiation. Analysis of the mechanism that underlies the maintenance of this totipotency requires the ability to isolate and study all stages of the germ cell lineage. The primordial germ cells (PGC) are the earliest identifiable germ cells in the embryo. It has not previously been possible to isolate PGC in sufficient numbers and purity to facilitate biochemical and/or molecular analysis. We report here that the use of a monoclonal antibody in combination with flow cytometry does permit the isolation of reasonably large and pure yields of viable mouse PGC. 相似文献
995.
996.
Namhoe Baek Jong-Min Woo Cecil Han Eunyoung Choi Inju Park Do Han Kim Edward M Eddy Chunghee Cho 《Reproductive biology and endocrinology : RB&E》2008,6(1):32
Background
Spermatogenesis and fertilization are highly unique processes. Discovery and characterization of germ cell-specific genes are important for the understanding of these reproductive processes. We investigated eight proteins encoded by novel spermatogenic cell-specific genes previously identified from the mouse round spermatid UniGene library. 相似文献997.
998.
We quantify, track and explain the distribution of overweight and of hypertension across Chinese provinces differentiated by their degree of urbanicity over the period 1991–2004. We construct an index of urbanicity from longitudinal data on community characteristics from the China Health and Nutrition Survey and compute, for the first time, a rank-based measure of inequality in disease risk factors by degree of urbanicity. Prevalence rates of overweight and hypertension almost doubled between 1991 and 2004 and these disease risk factors became less concentrated in more urbanized areas. Decomposition analysis reveals that one-half of the urbanicity-related inequality in overweight is directly attributable to community level characteristics, while for hypertension the contribution of such characteristics increased from 20% in 1991 to 62% in 2004. At the individual level, lower engagement in physical activity and farming explain more than half of the urban concentration of overweight and a rising share (28%) of the greater prevalence of hypertension in more urbanized areas. Higher incomes explain around one-tenth of the urban concentration of both overweight and hypertension, while the education advantage of urban populations has a similar sized offsetting effect. 相似文献
999.
1000.