首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   152篇
  免费   13篇
  2021年   1篇
  2019年   1篇
  2016年   2篇
  2015年   3篇
  2014年   7篇
  2013年   7篇
  2012年   5篇
  2011年   5篇
  2010年   5篇
  2009年   4篇
  2008年   3篇
  2007年   3篇
  2006年   2篇
  2005年   6篇
  2004年   2篇
  2003年   5篇
  2002年   7篇
  2001年   5篇
  2000年   3篇
  1999年   5篇
  1998年   2篇
  1997年   2篇
  1996年   2篇
  1995年   4篇
  1994年   3篇
  1993年   4篇
  1992年   4篇
  1991年   3篇
  1990年   8篇
  1989年   7篇
  1988年   5篇
  1987年   5篇
  1985年   1篇
  1984年   1篇
  1983年   4篇
  1982年   7篇
  1980年   4篇
  1979年   2篇
  1978年   4篇
  1977年   2篇
  1976年   4篇
  1975年   3篇
  1974年   2篇
  1973年   1篇
排序方式: 共有165条查询结果,搜索用时 15 毫秒
91.
92.
Presentation of three clinical cases that illustrate the current multidisciplinary care in cervical, endometrium and ovary cancer.  相似文献   
93.
A DNA construct containing the human alpha 1-antitrypsin gene including 1.5 and 4 kb of 5' and 3' flanking sequences, was microinjected into the pronucleus of rabbit embryos. The recombinant human protein was (a) expressed in the blood circulation of F0 and F1 transgenic rabbits at an average concentration of 1 mg ml-1, (b) shown to be fully active and (c) shown to be separable from its rabbit counterpart. Transgenic rabbits might represent a novel source of human proteins of therapeutic interest.  相似文献   
94.
Examination of 18 complete and 6 partial sequences of the major outer- membrane protein from 24 chlamydiae isolates was used to reconstruct their evolutionary relationships. From this analysis, assuming that the clades with 100% bootstrap support are correct, come the following conclusions: (1) The tree of these sequences is not congruent with the phylogeny of the hosts, and thus host switching would seem to have occurred, thereby limiting the extent to which there has been coevolution of parasite and host. (2) The tree is also noncongruent with clustering by type of cell infected, thereby limiting the extent to which there has been coevolution of parasite and the cell type that it infects. (3) The tree is also noncongruent with clustering by the organ infected (eyes or genitalia), thereby limiting the extent to which there has been coevolution of parasite and the organ that it infects. (4) The tree is also noncongruent with genital strains arising from lymphogranuloma venereum strains. (5) The tree is also noncongruent with the geographic site at which the isolates were obtained, thereby limiting the extent of divergence explained by geographic separation. (6) There are estimated to be 185 amino acid positions that are invariable (as opposed to unvaried) in the major outer-membrane protein. There are 10 unvaried positions in the variable domains, of which 9 appear to be invariable, giving some reason to hope that development of a vaccine might be possible. (7) The rate of change of this protein is too small to see increased divergence over the time span of isolation of these genes, giving hope to any vaccine having longevity. Bootstrapping supports those portions of the tree on which the first five conclusions above depend. The picture that these results provide is more one of pathogen versatility than one of coevolutionary constraints. In addition, we examined 10 60-KDa, outer-membrane protein- 2 genes, all but one of which were from these same strains. The tree was not, among the trachomatis strains, congruent with the major-outer- membrane protein tree, suggesting that gene exchange could be occurring among strains. Moreover, there is an apparent slowdown in divergence in this gene, among the trachomatis strains.   相似文献   
95.
96.
The pelvic MRI allows a better morphological analysis of the uterus (cervix and body) and ovaries compared to CT scan either before or after injection. MRI is the modality of choice for preoperative staging and follow-up of cervical and endometrial tumors. MRI assessed tumor response, detect recurrences. MRI also allows better characterization of ovaries lesions.  相似文献   
97.
Aquous extracts of brewery draff injected intravenously into ewes and cows induced prolactin and growth hormone (GH) secretion. The same draff added to the feed of cows appeared to be unable to significantly stimulate the blood level of prolactin and GH. In these experimental conditions, milk production was not enhanced by draff. Pure beta-glucan extracted from barley also stimulated hormone secretion when administered by the intravenous route. Barley, bier and draff therefore contain a beta-glucan-like factor which stimulates lactogenic hormone secretion. The amount present in draff is probably unable to cause an increase in hormones when administered orally. Hence, the well-established stimulatory effect of draff on milk production results from their nutritive value rather than from their ability of modulating the endocrine system.  相似文献   
98.
99.
Various drugs added to the culture medium of rabbit mammary gland were assayed for their capacity to affect the lactogenic and the mammogenic activities of prolactin. Three lysosomotropic agents NH4Cl, chloroquine and methylamine which were previously demonstrated to inhibit the degradation of the hormone-receptor complex after its internalization (down-regulation) did not prevent the initiation of casein synthesis, of lactose synthetase activity and of DNA synthesis. Five microtubule disrupting drugs, colchicine, colcemid, vinblastin, podophyllotoxin and nocodazole inhibited the induction of casein and DNA synthesis by prolactin whereas two inactive analogues, trimethylcolchicinic acid and lumicolchicine had no effect. None of these drugs exhibited any general cytotoxic effect as judged by the capacity of the tissue to incorporate 14C aminoacids into total proteins and 3H-uridine into total RNA. The microtubule disrupting drugs did not greatly reduce the rate of casein synthesis in the cultured mammary tissue explanted from lactating rabbits. The data suggest that the down-regulation of prolactin receptor is not strictly required for the two considered prolactin activities. By contrast, the integrity of microtubules, or at least of structures in which tubulin is involved, is necessary to ensure a normal transmission of the prolactin information responsible for the initiation of milk and DNA synthesis. In addition, the fact that the lactogenic and the mammogenic activities of prolactin are affected by the same drugs suggests that these two properties of the hormone are mediated by cellular mechanisms which have at least one common step.  相似文献   
100.
Insect‐induced galls on plants comprise species‐rich but self‐contained communities of herbivores and natural enemies. In the present study, we focus on galls induced by cynipid gall wasps on oaks, and on the least‐known trophic level that these galls contain: inquilines. These insects, also cynipids, feed on gall tissue and are an abundant but taxonomically poorly understood part of an otherwise well‐studied system. We used DNA sequence data to examine spatial patterns in the genetic diversity of Synergus umbraculus Olivier 1791 (Hymenoptera: Cynipidae: Synergini), a widespread species attacking many host galls across the Western Palaearctic. Analysis of 239 cytochrome b sequences revealed eight haplogroups showing significant phylogeographic pattern across the Western Palaearctic, corresponding to putative glacial refugia in Iberia, Central Europe, Turkey, and Iran. There were significant genetic discontinuities across the Pyrenees and the Anatolian diagonal but no impact of the Alps, suggesting that significant discontinuities have biotic rather than physical causes. Detailed analysis of sites in the Carpathian Basin reveal a high diversity and low spatial structure, and identify Central Europe as the source of colonists for Quaternary colonization of Germany, France, and Britain. We found no evidence for host‐associated differentiation of S. umbraculus lineages associated with the most common cynipid host galls, suggesting frequent shifts within the host gall assemblage by inquiline lineages. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102 , 750–764.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号