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   1510篇
  免费   92篇
  国内免费   16篇
耳鼻咽喉   9篇
儿科学   65篇
妇产科学   33篇
基础医学   175篇
口腔科学   30篇
临床医学   162篇
内科学   317篇
皮肤病学   40篇
神经病学   62篇
特种医学   187篇
外国民族医学   1篇
外科学   128篇
综合类   18篇
一般理论   1篇
预防医学   64篇
眼科学   24篇
药学   147篇
中国医学   1篇
肿瘤学   154篇
  2023年   8篇
  2022年   8篇
  2021年   23篇
  2020年   20篇
  2019年   35篇
  2018年   55篇
  2017年   38篇
  2016年   18篇
  2015年   27篇
  2014年   47篇
  2013年   58篇
  2012年   83篇
  2011年   44篇
  2010年   60篇
  2009年   60篇
  2008年   59篇
  2007年   61篇
  2006年   55篇
  2005年   58篇
  2004年   45篇
  2003年   58篇
  2002年   37篇
  2001年   42篇
  2000年   54篇
  1999年   42篇
  1998年   38篇
  1997年   35篇
  1996年   34篇
  1995年   25篇
  1994年   24篇
  1993年   21篇
  1992年   28篇
  1991年   20篇
  1990年   29篇
  1989年   24篇
  1988年   17篇
  1987年   25篇
  1986年   26篇
  1985年   22篇
  1984年   18篇
  1983年   8篇
  1982年   9篇
  1981年   11篇
  1979年   12篇
  1978年   8篇
  1977年   13篇
  1976年   16篇
  1974年   8篇
  1972年   8篇
  1968年   7篇
排序方式: 共有1618条查询结果,搜索用时 921 毫秒
81.
82.

Background  

Efficient delivery strategies for health interventions are essential for high and sustainable coverage. We report impact of a change in programmatic delivery strategy from routine delivery through the Expanded Programme on Immunization (EPI+) approach to twice-yearly mass distribution campaigns on coverage of vitamin A supplementation in Tanzania  相似文献   
83.
The purpose of the present investigation was to assess satellite cell populations and morphology in m. vastus lateralis biopsies obtained from young (20-30 years) and older (65-75 years) healthy, sedentary men and women. Multiple muscle biopsies were obtained from 14 young individuals (men, n = 7; women, n = 7) and 15 older individuals (men, n = 8; women, n = 7). Muscle fibers were viewed longitudinally using a Zeiss EM 10 CA electron microscope. All myonuclei and satellite cells were counted and satellite cells were photographed for morphological analysis. The proportion of satellite cells [satellite cells/(myonuclei + satellite cells)] did not differ among the four subject groups (1.7-2.8%), nor did proportions differ when subject groups were combined for age and gender comparisons. Few morphological differences were noted between groups; however, lipofuscin granules were more prominent in satellite cells from older subjects and women demonstrated significantly larger satellite cell and satellite cell nucleus areas than men. Mitochondria from satellite cells (regardless of group) were more pallid and exhibited fewer cristae than mitochondria located in the adjacent muscle fiber. The results of the current investigation suggest that, despite findings in animal models, satellite cell populations are not significantly lower in healthy, sedentary older compared to young adult men and women.  相似文献   
84.
Previous studies have indicated the importance of allometric scaling of VO2max for body size. However, no information is available on adjusting maximal cardiac output (Q max) and stroke volume (SVmax) for body dimensions. The allometric exponent b was determined for the equation Y=aX b (where Y is the physiological outcome and X is the anthropometric variable) for VO2max, Q max, and SVmax relative to mass, height, and body surface area (BSA) in 24 premenarcheal girls (mean age 12.2 years) during cycle testing. Values for b were 1.08 and 1.05 for BSA relative to Q max and SVmax, approximating that of 1.0 using the traditional ratio standard (cardiac index and stroke index). Exponents of body mass relative to VO2max, Q max, and SVmax (0.55, 0.55, and 0.59, respectively) eliminated the effects of body size, but the ratio standard (M 1.0) did not. In this group of subjects, use of the ratio standard BSA was an appropriate means of adjusting maximal values of Q and SV for body size.  相似文献   
85.
A new amino acid mixture for incorporation into medical foods for the treatment of hyperphenylalaninemia has been tested in a regular clinic. The mix is designed to be as unobtrusive as possible, consistent with good nutrition. After more than 1 year of trial as a beverage, we have shown that it is safe and well tolerated but that plasma phenylalanine is no better controlled than with some other products. The mix can be incorporated into a large number of different foods without affecting the taste. Occult monitoring of the quantity of medical foods purchased compared with the amounts reported to be consumed in diet histories provides an excellent way to monitor dietary compliance.  相似文献   
86.
Surveillance of antimicrobial resistance in bacteria from animal origin in France is organised by the French Agency for Food Safety (Agence Française de Sécurité Sanitaire des Aliments, AFSSA) through two types of networks. The first collects non-human zoonotic Salmonella strains in one centre (AFSSA, Paris) where they are tested for their antimicrobial susceptibility. The others, managed by AFSSA Lyon, deal with bovine pathogenic strains and are multicentric, that is they collecting antibiotic sensitivity and other data from the local public veterinary diagnostic laboratories. This requires standardisation of the methods used in each partner laboratory. Statistical analysis of any change in French resistance patterns can be monitored by these three networks either as a function of strain pathogenicity and/or of the ecological origin of the isolate. The system also encourages efficient collaboration between veterinarians and the laboratory. Such collaboration improves both the quality of routine antibiotic testing and understanding of the molecular mechanisms underlying resistance.  相似文献   
87.
88.
Serotonin (5-HT) is present in high concentration in enterochromaffin cells throughout the gastrointestinal tract, where it plays a very important role, being involved, e.g., in peristaltic and secretory reflexes in response to chemical or mechanical stimuli of the gut. Intestinal 5-HT is inactivated by metabolic degradation after cellular uptake mediated by the serotonin transporter SERT. This mini-review summarizes some recent data obtained by our group on the importance, regional distribution and cell membrane localization of SERT in the rat intestine. From our results, we conclude that SERT is located both at the apical and basolateral cell membranes of intestinal epithelial cells in the three intestinal regions studied: jejunum, ileum and colon. Moreover, we also conclude that inhibition of SERT causes an increase in transmural transport of 5-HT in these three intestinal segments, probably because it increases the extracellular concentration of 5-HT. Consequently, SERT inhibition will be able to cause an increase in the physiological responses of the tissue to this amine. The repercussions of this phenomenon are discussed.  相似文献   
89.
90.
Cooper  KL; Beabout  JW; McLeod  RA 《Radiology》1985,157(1):15-17
Insufficiency fractures in the supraacetabular region were identified in five women, aged 55-83 years. Factors contributing to the diminished resistance of their bones included postmenopausal osteoporosis, steroid therapy, radiation therapy, and rheumatoid arthritis. The supraacetabular fractures were seen on routine radiographs as hazy bands of sclerosis located immediately above and parallel to the acetabular roof. All five patients had additional fractures in the spine or pelvis. Supraacetabular insufficiency fractures may be an unsuspected cause of hip pain, especially in older women.  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