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   400篇
  免费   26篇
  国内免费   11篇
耳鼻咽喉   6篇
儿科学   9篇
妇产科学   8篇
基础医学   69篇
口腔科学   7篇
临床医学   15篇
内科学   127篇
神经病学   15篇
特种医学   5篇
外科学   77篇
综合类   3篇
预防医学   15篇
眼科学   1篇
药学   34篇
中国医学   1篇
肿瘤学   45篇
  2023年   4篇
  2022年   4篇
  2021年   10篇
  2020年   4篇
  2019年   4篇
  2018年   8篇
  2017年   3篇
  2016年   6篇
  2015年   4篇
  2014年   13篇
  2013年   6篇
  2012年   25篇
  2011年   9篇
  2010年   6篇
  2009年   11篇
  2008年   28篇
  2007年   17篇
  2006年   18篇
  2005年   28篇
  2004年   29篇
  2003年   21篇
  2002年   28篇
  2001年   17篇
  2000年   28篇
  1999年   18篇
  1998年   6篇
  1997年   5篇
  1995年   15篇
  1994年   3篇
  1993年   3篇
  1992年   5篇
  1991年   9篇
  1990年   4篇
  1989年   7篇
  1988年   2篇
  1987年   5篇
  1986年   2篇
  1985年   3篇
  1983年   1篇
  1980年   1篇
  1979年   2篇
  1978年   1篇
  1977年   2篇
  1974年   2篇
  1973年   2篇
  1971年   2篇
  1970年   1篇
  1969年   1篇
  1968年   1篇
  1966年   1篇
排序方式: 共有437条查询结果,搜索用时 15 毫秒
11.
European Journal of Clinical Microbiology & Infectious Diseases - The aim of this study is to clarify the characteristics of gram-negative bacteremia (GNB), including extended-spectrum...  相似文献   
12.
Recent studies have highlighted the mechanism of vascular and axonal guidance to ensure proper morphogenesis and organogenesis. We aimed to perform global mapping of developing neurovascular networks during craniofacial development of embryonic mice. To this end, we developed histology‐based three‐dimensional (3D) reconstructions using paraffin‐embedded serial sections obtained from mouse embryos. All serial sections were dual‐immunolabeled with Pecam1 and Pgp9.5/Gap43 cocktail antibodies. All immunolabeled serial sections were digitized with virtual microscopy to acquire high spatial resolution images. The 3D reconstructs warranted superior positional accuracy to trace the long‐range connectivity of blood vessels and individual cranial nerve axons. It was feasible to depict simultaneously the details of angiogenic sprouting and axon terminal arborization and to assess quantitatively the locoregional proximity between blood vessels and cranial nerve axons. Notably, 3D views of the craniofacial region revealed the following: Branchial arch arteries and blood capillary plexi were formed without accompanying nerves at embryonic day (E) 9.5. Cranial nerve axons began to grow into the branchial arches, developing a labyrinth of small blood vessels at E10.5. Vascular remodeling occurred, and axon terminals of the maxillary, mandibular, chorda tympani, and hypoglossal nerve axons had arborized around the lateral lingual swellings at E11.5. The diverged patterning of trigeminal nerves and the arterial branches from the carotid artery became congruent at E11.5. The overall results support the advantage of dual‐immunolabeling and 3D reconstruction technology to document the architecture and wiring of the developing neurovascular networks in mouse embryos. Anat Rec, 298:1824–1835, 2015. © 2015 Wiley Periodicals, Inc.  相似文献   
13.
14.
15.
16.
The mechanisms responsible for the 24-h difference in the time of the next ovulation after litter removal between early and late lactating rats were investigated. At 11.00 h on day 5 of lactation, concentrations of oestradiol-17 beta and inhibin activity in ovarian venous plasma were lower than those on day 17, corresponding to the absence of healthy Graafian follicles. After removal of the litter on day 5 of lactation a small surge of FSH with a steady increase in basal levels of LH occurred to initiate follicular maturation, and ovulation occurred 4 days later. After removal of the litter on day 17 of lactation a surge of FSH was not observed, due to high levels of inhibin activity in ovarian venous plasma, until the time of preovulatory surges of gonadotropin which occurred 2 days later and resulted in ovulation the next morning. Prolactin concentrations decreased similarly in both groups abruptly after removal of the litter. A decrease in plasma concentrations of progesterone occurred 42 h after removal of the litter on day 5, though it occurred 18 h after removal of the litter on day 17. These results indicate that the 24-h delay of ovulation after litter removal on day 5 of lactation, as compared with the time of ovulation after litter removal on day 17, is due probably to the absence of healthy antral follicles and high activity of corpora lutea secreting progesterone at the time of litter removal.  相似文献   
17.
Pentachlorophenol (PCP), a component of biocides and a contaminant in diverse tissue samples from humans from various geographic areas, disrupts regulatory effects of thyroid hormones. Here we examined the effects of developmental exposure of rats to PCP on various aspects of brain development, male reproductive function, and adrenal function, all of which are under thyroid hormones regulation. PCP was administered to dams and their offspring via drinking water (6.6 mg l−1) during gestation and lactation. Tissue samples were obtained from dams, 3-week-old weanling pups, and 12-week-old pups. Gene expressions of thyroid hormone receptor β1 and synapsin I, factors that promote brain growth, was increased in the cerebral cortex of PCP-treated weanling females, whereas plasma concentrations of total thyroxine were decreased in dams and weanling pups, and plasma thyroid-stimulating hormone concentrations were higher in PCP-treated weanling males. PCP caused a decrease in plasma corticosterone concentrations in 12-week-old female rats, but not in male rats or weanling females. PCP-treated male pups had significantly increased testis weight at 12 week of age. No overt signs of toxicity were noted throughout this study. Our results show that PCP exposure during development causes thyroid function vulnerability, testicular hypertrophy in adults, and aberrations of brain gene expression.  相似文献   
18.
19.
Plasma concentrations of inhibin pro-alphaC, inhibin A and inhibin B were determined by enzyme-linked immunosorbent assay at 6 h intervals throughout the 4-day oestrous cycle of the golden hamster. Plasma concentrations of follicle-stimulating hormone (FSH) and oestradiol-17beta were also measured by radioimmunoassay during the oestrous cycle. Plasma concentrations of inhibin A increased from the early morning of day 1 (day 1=day of ovulation) and reached plateau levels at 0500 h on day 2. An abrupt increase in plasma concentrations of inhibin A was found at 1700 h on day 4, when the preovulatory FSH surge was observed. An increase in plasma concentrations of inhibin B occurred on day 1 and reached plateau levels at 1700 h on day 1. The levels remained elevated until 0500 h on day 4 and declined gradually by 2300 h on day 4. Plasma concentrations of inhibin pro-alphaC gradually increased with some fluctuation from day 1 to 1700 h on day 4 and then declined. Significant negative relationships were noted between plasma FSH and both dimeric forms of inhibin from day 1 to day 3. Significant positive relationships were found between plasma oestradiol-17beta and inhibin A or inhibin pro-alphaC throughout the oestrous cycle. In contrast, no significant relationship was found between plasma oestradiol-17beta and inhibin B. These findings suggest that both dimeric forms of inhibin play a role in the regulation of FSH secretion during follicular development. These findings also suggest that inhibin pro-alphaC could be secreted primarily by large follicles, and early atretic follicles could also be responsible for inhibin pro-alphaC secretion. On the other hand, the secretory pattern of dimeric inhibins might shift from inhibin B to inhibin A with follicular development.  相似文献   
20.
Sulpiride and ethylene glycol monomethyl ether (EGME) are known ovarian toxicants that stimulate prolactin (PRL) secretion, resulting in hypertrophy of the corpora lutea and increased progesterone (P4) production. The purpose of the present study was to investigate how the PRL stimulatory agents affected uterine carcinogenesis and to clarify the effects of PRL on endometrial adenocarcinoma progression in rats. Ten‐week‐old female Donryu rats were treated once with N‐ethyl‐N′‐nitro‐N‐nitrosoguanidine (20 mg kg?1), followed by treatment with sulpiride (200 ppm) or EGME (1250 ppm) from 11 weeks of age to 12 months of age. Sulpiride treatment inhibited the incidence of uterine adenocarcinoma and precancerous lesions of atypical endometrial hyperplasia, whereas EGME had no effect on uterine carcinogenesis. Sulpiride markedly prevented the onset of persistent estrus throughout the study period, and EGME delayed and inhibited the onset of persistent estrus. Moreover, sulpiride‐treated animals showed high PRL and P4 serum levels without changes in the levels of estradiol‐17β, low uterine weights and histological luteal cell hypertrophy. EGME did not affect serum PRL and P4 levels. These results suggest that the prolonged low estradiol‐17β to P4 ratio accompanied by persistent estrous cycle abnormalities secondary to the luteal stimulatory effects of PRL may explain the inhibitory effects of sulpiride on uterine carcinogenesis in rats. Copyright © 2015 John Wiley & Sons, Ltd.  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