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   90276篇
  免费   4601篇
  国内免费   201篇
耳鼻咽喉   1100篇
儿科学   2010篇
妇产科学   1854篇
基础医学   12067篇
口腔科学   3781篇
临床医学   6885篇
内科学   21635篇
皮肤病学   2048篇
神经病学   7877篇
特种医学   2046篇
外科学   11703篇
综合类   421篇
一般理论   39篇
预防医学   8537篇
眼科学   1662篇
药学   6206篇
中国医学   360篇
肿瘤学   4847篇
  2023年   571篇
  2022年   414篇
  2021年   1464篇
  2020年   900篇
  2019年   1535篇
  2018年   2758篇
  2017年   1838篇
  2016年   1885篇
  2015年   2528篇
  2014年   2667篇
  2013年   3721篇
  2012年   7753篇
  2011年   8066篇
  2010年   3621篇
  2009年   2664篇
  2008年   6673篇
  2007年   6848篇
  2006年   6745篇
  2005年   6533篇
  2004年   5871篇
  2003年   5316篇
  2002年   5001篇
  2001年   1861篇
  2000年   2338篇
  1999年   1260篇
  1998年   315篇
  1997年   218篇
  1996年   224篇
  1995年   208篇
  1994年   175篇
  1993年   159篇
  1992年   232篇
  1991年   223篇
  1990年   139篇
  1989年   154篇
  1988年   129篇
  1987年   114篇
  1986年   129篇
  1985年   133篇
  1984年   145篇
  1983年   102篇
  1982年   113篇
  1981年   99篇
  1980年   99篇
  1979年   68篇
  1978年   62篇
  1977年   62篇
  1974年   72篇
  1973年   55篇
  1967年   58篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
3.
4.
5.
OBJECTIVE: Gelastic seizures are a frequent and well established manifestation of the epilepsy associated with hypothalamic hamartomas. The scalp EEG recordings very seldom demonstrate clear spike activity and the information about the ictal epilepsy dynamics is limited. In this work, we try to isolate epileptic rhythms in gelastic seizures and study their generators. METHODS: We extracted rhythmic activity from EEG scalp recordings of gelastic seizures using decomposition in independent components (ICA) in three patients, two with hypothalamic hamartomas and one with no hypothalamic lesion. Time analysis of these rhythms and inverse source analysis was done to recover their foci of origin and temporal dynamics. RESULTS: In the two patients with hypothalamic hamartomas consistent ictal delta (2-3 Hz) rhythms were present, with subcortical generators in both and a superficial one in a single patient. The latter pattern was observed in the patient with no hypothalamic hamartoma visible in MRI. The deep generators activated earlier than the superficial ones, suggesting a consistent sub-cortical origin of the rhythmical activity. CONCLUSIONS: Our data is compatible with early and brief epileptic generators in deep sub-cortical regions and more superficial ones activating later. SIGNIFICANCE: Gelastic seizures express rhythms on scalp EEG compatible with epileptic activity originating in sub-cortical generators and secondarily involving cortical ones.  相似文献   
6.
BACKGROUND: Stressful conditions lead to formation of excessive free radicals, and lipid peroxidation is one of the major outcomes of free radical-mediated injury that directly damages membranes and generates a number of secondary products. OBJECTIVES: To determine the levels of malondialdehyde, an end product of lipid peroxidation, according to demographic and occupational variables in workers of a prehospital emergency service and to analyse the relationship between malondialdehyde levels and burnout. MATERIAL AND METHODS: One hundred and eleven healthy workers of a prehospital emergency service and eighty aged-matched healthy individuals of both sexes as a control group were surveyed. Malondialdehyde levels were measured by the Bull and Marnett method. To measure burnout, the Maslach Burnout Inventory was used. RESULTS: Professional category is associated with lipid peroxidation and burnout levels (Malondialdehyde levels were: physicians 338.10+/-14.47, nurses 329.17+/-12.62 and technicians 296.74+/-14.28; burnout levels were: physicians 41.29+/-3.59, nurses 37.38+/-6.05 and technicians 35.33+/-5.87). Working at night and in the evening increased malondialdehyde and burnout levels. Malondialdehyde levels increase with age. No significant variations with respect to sex were detected. Significant variations in malondialdehyde levels were detected between singles (303.13+/-12.74) and married people (344.43+/-13.43) but not with respect to divorcees (326.44+/-11.74). Significant differences were detected in erythrocyte malondialdehyde levels between smokers (341.37+/-17.09) and nonsmokers (302.21+/-12.38), but not for alcohol consumption. CONCLUSIONS: These findings suggest a positive correlation between malondialdehyde, a biomarker of lipid peroxidation and occupational stress, as estimated by elements of the Maslach Burnout Inventory, and oxidative stress.  相似文献   
7.
We report on 3 patients with pseudoathetosis, which are involuntary, slow, writhing movements due to loss of proprioception.  相似文献   
8.
To produce a stable epidermis, keratinocytes need to be firmly attached to the basement membrane. However, following wounding, keratinocytes are required to develop a migratory phenotype in order to reepithelialize the wound. To investigate some of the issues underlying reepithelialization, we have developed a three-dimensional in vitro model of tissue-engineered skin, comprising sterilized human dermis seeded with human keratinocytes and dermal fibroblasts. Using this model, we have shown that the inclusion of fibroblasts within the model increases the stability of keratinocyte attachment. We have also demonstrated that keratinocyte migration occurs most effectively in the absence of a basement membrane and following the inclusion of fibroblasts in the model. In addition, subjecting the keratinocyte layer to mechanical trauma induces a migratory phenotype. We conclude that this three-dimensional in vitro wound model can be used to increase our understanding of the factors that enhance keratinocyte migration and hence wound healing in vivo.  相似文献   
9.

Background  

Patient falls in hospitals are common and may lead to negative outcomes such as injuries, prolonged hospitalization and legal liability. Consequently, various hospital falls prevention programs have been implemented in the last decades. However, most of the programs had no sustained effects on falls reduction over extended periods of time.  相似文献   
10.
Consecutive patients (n = 215) who were referred to optometric (55%) or multidisciplinary (45%) low-vision services and above 50 years of age were recruited from four hospitals in the Netherlands. They completed two vision-related quality of life questionnaires, the Vision Quality of Life Core Measure (VCM1) and the Low Vision Quality of Life Questionnaire (LVQOL), before their first visit with low-vision services and 1 year later. At follow-up, patients referred to multidisciplinary low-vision services had lower scores on the mobility subscale of the LVQOL than patients referred to optometric low-vision services [5.3 points; 95% confidence interval (CI): 0.2-10.5]. Paired sample t-tests for the two groups of patients taken together show improvement for the VCM1 (3.1 points; 95% CI: 0.6-5.6) and deterioration for the basic aspects of vision (3.5 points; 95% CI: 1.1-5.9) and the mobility (6.6 points; 95% CI: 3.7-9.5) subscales of the LVQOL. In conclusion, people referred to optometric services showed less deterioration in mobility than those referred to multidisciplinary services. No differences were observed for any of the other subscales of the LVQOL and the VCM1. Future research in this field should include randomized controlled designs comparing low-vision services with no treatment or placebo.  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