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   27484篇
  免费   1918篇
  国内免费   51篇
耳鼻咽喉   197篇
儿科学   886篇
妇产科学   645篇
基础医学   3680篇
口腔科学   282篇
临床医学   4017篇
内科学   4904篇
皮肤病学   531篇
神经病学   2857篇
特种医学   507篇
外科学   2814篇
综合类   223篇
一般理论   42篇
预防医学   3616篇
眼科学   422篇
药学   1650篇
中国医学   22篇
肿瘤学   2158篇
  2024年   32篇
  2023年   260篇
  2022年   368篇
  2021年   808篇
  2020年   595篇
  2019年   772篇
  2018年   934篇
  2017年   692篇
  2016年   731篇
  2015年   740篇
  2014年   1072篇
  2013年   1552篇
  2012年   2318篇
  2011年   2411篇
  2010年   1285篇
  2009年   1119篇
  2008年   1885篇
  2007年   1971篇
  2006年   1813篇
  2005年   1673篇
  2004年   1518篇
  2003年   1317篇
  2002年   1300篇
  2001年   181篇
  2000年   165篇
  1999年   202篇
  1998年   237篇
  1997年   193篇
  1996年   148篇
  1995年   124篇
  1994年   125篇
  1993年   106篇
  1992年   90篇
  1991年   69篇
  1990年   77篇
  1989年   52篇
  1988年   49篇
  1987年   34篇
  1986年   37篇
  1985年   38篇
  1984年   42篇
  1983年   24篇
  1982年   32篇
  1981年   28篇
  1980年   19篇
  1979年   26篇
  1976年   24篇
  1974年   14篇
  1973年   18篇
  1971年   14篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
43.
Chronic food restriction has been shown to enhance glucose metabolism in adipocytes from lean Zucker rats at 10, 26, and 52 weeks of age compared to ad libitum-fed lean rats. Only adipocytes from food restricted 10-week-old obese rats demonstrated this response. In this study, lean and obese rats were food restricted from 5 until 14 weeks of age to determine the age at which adipocytes from obese rats were no longer affected by this intervention. Effects of 1 week of refeeding were also determined. When the rats were killed, body weights were highest in control rats followed by restricted/refed and then restricted rats within each genotype. Epididymal pad weights of lean rats were resistant to dietary intervention, while those of obese-restricted and obese-restricted/refed rats weighed less than pads of obese-control rats. Retroperitoneal pad weight was lowered by food restriction in both genotypes; but only that of lean-restricted/refed rats totally recovered with refeeding. Adipocytes of lean-restricted rats had the highest conversion of glucose to CO2. Glyceride-glycerol production was higher in obese compared to lean rats, but restricted rats had elevated conversion of glucose to fatty acids. In general, these results indicate that by 14 weeks of age obese Zucker rats no longer respond to food restriction with an elevated rate of glucose metabolism in adipocytes.  相似文献   
44.
Disturbances of visual cognition, visuomotor performance, and visual memory have been described frequently in Huntington's disease (HD). Early stage visual abnormalities could contribute to these deficits. We evaluated visual processing in 20 control subjects who were non-gene carriers at risk for HD, nine presymptomatic gene-positive subjects, and eight subjects with a recent diagnosis of Huntington's disease. Visual perceptual tests of contrast sensitivity and motion discrimination were used to probe early stage visual processing. Extraocular movements were evaluated in a neurologic examination, and the Digit Symbol test was used to test visual motor performance. Contrast sensitivity did not differ among the three groups. Motion discrimination was impaired in HD subjects but not in the presymptomatic gene carriers when compared to gene noncarriers. Among gene carriers, impaired motion discrimination performance was associated with poorer Digit Symbol performance and extraocular abnormalities. These findings suggest that the early stages of HD are associated with disturbances of motion perception as well as disruptions of visual motor and ocular motor performance.  相似文献   
45.
46.
Recommendations for increased consumption of protein are among the most common approaches of popular or fad diets. This review summarizes the effects of dietary protein on satiety, energy intake, thermogenesis, and weight loss, as well as its effect on a variety of health outcomes in adults. In short-term studies, dietary protein modulates energy intake via the sensation of satiety and increases total energy expenditure by increasing the thermic effect of feeding. Whereas these effects did not contribute to weight and fat loss in those studies in which energy intake was fixed, one ad libitum study does suggest that a high-protein diet results in a greater decrease in energy intake, and therefore greater weight and fat loss. In terms of safety, there is little long-term information on the health effects of high-protein diets. From the available data, however, it is evident that the consumption of protein greater than two to three times the U.S. Recommended Daily Allowance contributes to urinary calcium loss and may, in the long term, predispose to bone loss. Caution with these diets is recommended in those individuals who may be predisposed to nephrolithiasis or kidney disease, and particularly in those with diabetes mellitus.  相似文献   
47.
This paper reflects on a research project funded by a consortium of leading sheltered housing (SH) providers and their regulatory body, the Housing Corporation. The project aimed to ascertain which aspects of SH older people perceived to be central to their satisfaction and the methods they judged most appropriate to measuring this. We outline key policy developments of importance to SH (specifically the development of performance measurement regimes), and changes in the nature of SH, which are driving providers to re‐evaluate how they measure user satisfaction. We discuss the aims of the project, our methodology and findings, and conclude by raising critical questions about the process of measuring satisfaction within an increasingly managerialised housing system. We argue that this favours standardised methods of information gathering (such as questionnaires) rather than engage with clients in order to develop methods and systems capable of eliciting qualitative issues of concern to them. Our conclusions are, we believe, applicable to health and social care provision, where similar tensions exist around performance measurement and user satisfaction.  相似文献   
48.
This population-based study documented beta-blocker use in 59/569 cases with incident fracture and 112/775 controls. OR for fracture associated with beta-blocker use was 0.68 (95%CI, 0.49-0.96). Beta-blockers were associated with higher BMD at the total hip (2.5%) and UD forearm (3.6%) after adjusting for age, anthropometry, and thiazide use. Beta-blocker use is associated with reduced fracture risk and higher BMD. INTRODUCTION: Animal data suggests that bone formation is under beta-adrenergic control and that beta-blockers stimulate bone formation and/or inhibit bone resorption. MATERIALS AND METHODS: We evaluated the association between beta-blocker use, bone mineral density (BMD), and fracture risk in a population-based study in Geelong, a southeastern Australian city with a single teaching hospital and two radiological centers providing complete fracture ascertainment for the region. Beta-blocker use was documented for 569 women with radiologically confirmed incident fractures and 775 controls without incident fracture. Medication use and lifestyle factors were documented by questionnaire. RESULTS: Odds ratio for fracture associated with beta-blocker use was 0.68 (95% CI, 0.49-0.96) for any fracture. Adjusting for age, weight, medications, and lifestyle factors had little effect on the odds ratio. Beta-blocker use was associated with a higher BMD at the total hip (2.5%, p = 0.03) and ultradistal forearm (3.6%, p = 0.04) after adjustment for age, anthropometry, and thiazide use. CONCLUSION: Beta-blockers are associated with a reduction in fracture risk and higher BMD.  相似文献   
49.
OBJECTIVE: The purpose of this study was to evaluate a pilot occupational therapy wellness program designed to teach elders the importance of participation in meaningful social and community occupations to their quality of life. METHOD: Sixty-five older adults participated in this pilot wellness program held at each of three senior apartment complexes. Measures of health-related quality of life using the SF-36 Health Survey and frequencies of social and community participation from a program-specific intake form were completed by 39 participants before and after the 6-month program. Participants also evaluated components of the program through a satisfaction survey. RESULTS: Scores on the SF-36 Health Survey were significantly higher in vitality, social functioning, and the mental health summary scores following participation in the program. Participants reported an increased frequency of socialization and community participation with an average of 55% participating in at least three or more activities per week before the program to an average of 66% participating after the program. Participants who benefited the most attended more classes, were older, and were nondrivers. Eighty percent of those polled rated the pilot program as good or excellent. CONCLUSION: This pilot study provides additional support for prevention efforts for elders in the community. Wellness programs for seniors may be most effective if targeted to those who are older and nondrivers.  相似文献   
50.
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