全文获取类型
收费全文 | 337篇 |
免费 | 24篇 |
出版年
2023年 | 2篇 |
2021年 | 3篇 |
2020年 | 4篇 |
2018年 | 6篇 |
2016年 | 3篇 |
2015年 | 10篇 |
2014年 | 8篇 |
2013年 | 10篇 |
2012年 | 11篇 |
2011年 | 11篇 |
2010年 | 12篇 |
2009年 | 10篇 |
2008年 | 13篇 |
2007年 | 7篇 |
2006年 | 11篇 |
2005年 | 10篇 |
2004年 | 9篇 |
2003年 | 16篇 |
2002年 | 5篇 |
2001年 | 11篇 |
2000年 | 14篇 |
1999年 | 14篇 |
1998年 | 6篇 |
1996年 | 7篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1992年 | 11篇 |
1991年 | 5篇 |
1990年 | 10篇 |
1989年 | 2篇 |
1988年 | 5篇 |
1987年 | 7篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 2篇 |
1983年 | 5篇 |
1982年 | 4篇 |
1981年 | 11篇 |
1980年 | 3篇 |
1979年 | 12篇 |
1978年 | 14篇 |
1977年 | 7篇 |
1976年 | 4篇 |
1975年 | 9篇 |
1974年 | 7篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1967年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有361条查询结果,搜索用时 15 毫秒
1.
2.
PURPOSE: Evaluation of the fertility of a cohort of formerly bilaterally cryptorchid men in comparison with a group of formerly unilaterally cryptorchid men, and a group of control men. MATERIALS AND METHODS: Using a detailed questionnaire concerning paternity and factors related to paternity, a cohort of formerly bilateral cryptorchid men were studied and compared with men who had undergone orchiopexy for unilateral cryptorchidism, and a group of control men. All study subjects had had surgery at the Children's Hospital of Pittsburgh, Pittsburgh, Pa., between 1955 and 1975. A subset of the full cohort underwent clinical evaluation that included a physical examination, serum hormonal determination and semen analyses. RESULTS: Paternity rates are significantly lower among the formerly bilaterally cryptorchid men who have attempted to father a child (65.3%) as compared to the formerly unilaterally cryptorchid (89.7%; p < 0.001) and control men (93.2%; p < 0.001). Differences in the ability to father children are also apparent when semen and hormone levels are compared between the three groups. The bilateral group has significantly lower sperm density and inhibin B levels, and higher FSH and LH levels, than the unilateral and control groups. CONCLUSIONS: Men born with bilateral cryptorchidism have severely compromised fertility in adulthood. This reduction in fertility is clearly shown in comparisons of both paternity rates, and in semen and hormone analyses, between the formerly bilateral, formerly unilateral, and control groups. 相似文献
3.
4.
5.
6.
7.
8.
9.
10.
B A Coughlin H D White D L Purich 《Biochemical and biophysical research communications》1980,92(1):89-94
Brain microtubule protein, prepared by two types of recycling methods, undergoes “flash” phosphorylation in the presence of [γ-32p]ATP through sequential action of protein kinase and phosphoprotein phosphatase present in microtubule protein. SDS electrophoretic analysis indicates that MAP1, tau protein, and tubulin are poorly phosphorylated, and MAP2 is the major site of phosphorylation. To improve [32P]phosphoprotein stability in the presence of the kinase/phosphatase cycle, 3′,5′-cyclicAMP, orthophosphate, or fluoride ion may be added. After separation from tubulin by phosphocellulose chromatography, the MAP fraction exhibits autophosphorylation. Finally, the maximal extent of autophosphorylation is observed with an ATP regenerating system using ADP, [32P]acetyl-P, and bacterial acetate kinase; this results in the incorporation of 3–4 phosphoryl groups per MAP2 subunit. 相似文献