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   26088篇
  免费   1704篇
  国内免费   83篇
耳鼻咽喉   184篇
儿科学   814篇
妇产科学   628篇
基础医学   3938篇
口腔科学   453篇
临床医学   3761篇
内科学   4742篇
皮肤病学   440篇
神经病学   2732篇
特种医学   618篇
外科学   2145篇
综合类   173篇
一般理论   26篇
预防医学   2977篇
眼科学   443篇
药学   1929篇
  1篇
中国医学   56篇
肿瘤学   1815篇
  2023年   197篇
  2022年   301篇
  2021年   722篇
  2020年   474篇
  2019年   645篇
  2018年   784篇
  2017年   560篇
  2016年   611篇
  2015年   791篇
  2014年   919篇
  2013年   1463篇
  2012年   2035篇
  2011年   2179篇
  2010年   1143篇
  2009年   1062篇
  2008年   1783篇
  2007年   1845篇
  2006年   1793篇
  2005年   1676篇
  2004年   1584篇
  2003年   1459篇
  2002年   1290篇
  2001年   182篇
  2000年   144篇
  1999年   181篇
  1998年   229篇
  1997年   171篇
  1996年   166篇
  1995年   118篇
  1994年   127篇
  1993年   107篇
  1992年   77篇
  1991年   97篇
  1990年   83篇
  1989年   88篇
  1988年   54篇
  1987年   50篇
  1986年   56篇
  1985年   57篇
  1984年   73篇
  1983年   77篇
  1982年   71篇
  1981年   48篇
  1980年   51篇
  1979年   40篇
  1978年   23篇
  1977年   30篇
  1976年   24篇
  1975年   22篇
  1974年   23篇
排序方式: 共有10000条查询结果,搜索用时 703 毫秒
81.
82.
83.
OBJECTIVE: The objective of this study is to investigate the association between actigraphic estimates of the sleep-wake rhythm and a range of functional domains that contribute to well-being in demented elderly patients. METHOD: Eighty-seven women aged 85.5 +/- 5.9 years (mean +/- standard deviation) wore an actigraph for two weeks. Activity profiles were analyzed using nonparametric variables, including dichotomy indices, interdaily stability (IS), intradaily variability (IV), and relative amplitude (RA). The associations between these variables and cognitive, functional, behavioral, and emotional states (obtained from standardized neuropsychologic assessments and questionnaires administered to caregivers) were investigated by partial correlations and stepwise regressions. RESULTS: Cognitive, functional, behavioral, and emotional states showed medium to strong correlations with multiple rhythm variables. Partial correlations indicated that this could not be attributed to a uniform worsening with advancing cognitive decline. Stepwise regressions indicated three most distinctive rhythm variables: 1) the interdaily stability of the 24-hour rhythm was most strongly, negatively, related to cognitive decline and depression; 2) the median level of daytime activity was most strongly, negatively, related to impairments of function, of activities of daily living, and of social interaction; and 3) nocturnal restlessness was secondarily, positively, related to impairments of function and social interaction. CONCLUSION: Especially the interdaily stability and median daytime activity level, and secondarily nocturnal restlessness, showed a strong relationship with the functional status and well-being of demented elderly. This raises the possibility that treatments that enhance daytime activity and the stability of the rest-activity rhythm may improve well-being.  相似文献   
84.
Age‐related macular degeneration is a major cause of serious vision loss. The earliest stages of age‐related maculopathy may be defined by the size of the drusen present in the macula and the effects on vision. Further manifestations may include soft drusen, choroidal neovascularisation, macular haemorrhage and cicatricial or disciform degeneration of the macula. This report describes a patient with a macular haemorrhage, a choroidal neovascular membrane and serious loss of vision. In addition, the pathogenesis, diagnosis and treat‐ment options of macular degeneration are reviewed.  相似文献   
85.
Screening for osteoporotic vertebral fractures traditionally involves X-ray of the thoracic and lumbar spine. We evaluated use of dual energy X-ray technology in patients with osteoporosis. We found this technology useful in the clinic setting and it has advantages in that less radiation is delivered to the patient.  相似文献   
86.
Repeated isolation of neonatal rats produces persistent changes in physiology and behavior. In Experiment 1, we examined changes in plasma corticosterone (CORT) levels as a possible mechanism for the effects of isolation. Pups that were isolated from their mother and the nest for 1 h per day on postnatal days (PND) 2–9 were compared to control litters of pups that were either nonhandled or handled but not isolated. On PND 2, compared to nonhandled pups, handled pups had elevated CORT levels that returned to baseline levels within 30 to 60 min of return to the home cage. No significant elevation of CORT levels were found in handled pups on PND 9. The CORT levels of isolated pups were over twice those of nonhandled pups on PND 2 and four times those of nonhandled pups on PND 9. In Experiment 2, we investigated whether the increased CORT release in response to isolation on PND 9 was the result of the pups treatment on the previous six days as against an effect of maturation. Plasma CORT levels were measured in rat pups that were either isolated, handled or nonhandled on PNDs 2–8 during the conditions of isolation, handling and nonhandling on PND 9. There were no differences among the groups in basal plasma levels of CORT. Handling on PND 9 did not result in elevated CORT levels in any of the groups. All three groups showed a significant increase in plasma CORT levels after isolation on PND 9. However, the CORT response to isolation of pups previously isolated on PND 2–8 were significantly higher than pups that were either handled or nonhandled on PNDs 2–8. Thus, daily episodes of isolation potentiate the hypothalamic-pituitary-adrenal response to stress.  相似文献   
87.
88.
Abstract. Medical and social problems related to alcohol use are frequently seen in the ED. Often, the tempo of emergency medicine practice seems to preclude assessment beyond that required by the acute complaint. However, detection of ED patients with alcohol problems can occur using brief screening tools. This article was developed by members of the SAEM Substance Abuse Task Force, and describes screening tools that have been used successfully to identify atrisk and dependent drinkers. Their brevity, reproducibility, and accuracy vary somewhat, but screening can be realistically performed in the busy ED setting. The early detection of patients with alcohol problems would provide the opportunity for early intervention, and may reduce subsequent morbidity and mortality in this patient population.  相似文献   
89.
90.
Evaluating the clinical nurse specialist. A review   总被引:7,自引:0,他引:7  
This paper reviews evaluative studies on the role of clinical nurse specialists and aims to describe and categorise research according to the methods used. By using the structure, process and outcome framework a clear pattern of research development and evidence emerges. It appears that significant benefits accrue for patients from the contribution of nurse specialists, but more experimental studies with combined methods should now be applied to this area.  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