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   20229篇
  免费   1674篇
  国内免费   42篇
耳鼻咽喉   181篇
儿科学   658篇
妇产科学   412篇
基础医学   2935篇
口腔科学   263篇
临床医学   2630篇
内科学   3583篇
皮肤病学   275篇
神经病学   2264篇
特种医学   424篇
外科学   2137篇
综合类   364篇
一般理论   26篇
预防医学   2420篇
眼科学   383篇
药学   1464篇
中国医学   23篇
肿瘤学   1503篇
  2023年   141篇
  2022年   221篇
  2021年   497篇
  2020年   270篇
  2019年   441篇
  2018年   474篇
  2017年   350篇
  2016年   350篇
  2015年   433篇
  2014年   571篇
  2013年   904篇
  2012年   1341篇
  2011年   1326篇
  2010年   690篇
  2009年   643篇
  2008年   1074篇
  2007年   1182篇
  2006年   1081篇
  2005年   1041篇
  2004年   999篇
  2003年   908篇
  2002年   893篇
  2001年   326篇
  2000年   334篇
  1999年   296篇
  1998年   229篇
  1997年   186篇
  1996年   172篇
  1995年   141篇
  1994年   130篇
  1993年   127篇
  1992年   255篇
  1991年   270篇
  1990年   254篇
  1989年   256篇
  1988年   260篇
  1987年   231篇
  1986年   229篇
  1985年   167篇
  1984年   176篇
  1983年   151篇
  1982年   135篇
  1981年   135篇
  1980年   112篇
  1979年   137篇
  1978年   110篇
  1976年   99篇
  1975年   100篇
  1974年   140篇
  1973年   118篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
While previous randomised controlled trials and meta-analyses offer only limited evidence for the effectiveness of cognitive rehabilitation, qualitative studies examining patient perspectives report more positive outcomes. This meta-synthesis of qualitative studies examined patient perspectives of cognitive rehabilitation for memory, attention, and executive function problems in people with multiple sclerosis. Using set eligibility criteria, we screened electronic databases, reference lists, and academic networks for relevant papers. Seven papers (195 participants) were selected. Two independent researchers conducted quality appraisals of papers. Data analysis, guided by the thematic synthesis approach, yielded six main themes. These suggested that patients benefitted from the group environment in rehabilitation. Cognitive rehabilitation facilitated the participants’ reflection and awareness of their cognitive deficits, and was associated with increased knowledge and understanding of their illness. Increased strategy use was reported and associated with improvements in cognitive functioning and greater confidence and perseverance. Participants reported emotional and social improvements, and felt more optimistic. Overall, these changes had a positive impact on participants’ quality of life. This synthesis of qualitative studies indicates that people with multiple sclerosis who experience cognitive deficits benefit from cognitive rehabilitation programmes. This finding must, however, be viewed in light of the limitations of this meta-synthesis. The meta-synthesis was registered in the PROSPERO database under CRD42017040148.  相似文献   
3.
4.
5.
In some diseases, such as multiple sclerosis, lesion counts obtained from magnetic resonance imaging (MRI) are used as markers of disease progression. This leads to longitudinal, and typically overdispersed, count data outcomes in clinical trials. Models for such data invariably include a number of nuisance parameters, which can be difficult to specify at the planning stage, leading to considerable uncertainty in sample size specification. Consequently, blinded sample size re-estimation procedures are used, allowing for an adjustment of the sample size within an ongoing trial by estimating relevant nuisance parameters at an interim point, without compromising trial integrity. To date, the methods available for re-estimation have required an assumption that the mean count is time-constant within patients. We propose a new modeling approach that maintains the advantages of established procedures but allows for general underlying and treatment-specific time trends in the mean response. A simulation study is conducted to assess the effectiveness of blinded sample size re-estimation methods over fixed designs. Sample sizes attained through blinded sample size re-estimation procedures are shown to maintain the desired study power without inflating the Type I error rate and the procedure is demonstrated on MRI data from a recent study in multiple sclerosis.  相似文献   
6.
Recent work suggests that while voluntary episodic memory declines with age, involuntary episodic memory, which comes to mind spontaneously without intention, remains relatively intact. However, the neurophysiology underlying these differences has yet to be established. The current study used electroencephalography (EEG) to investigate voluntary and involuntary retrieval in older and younger adults. Participants first encoded sounds, half of which were paired with pictures, the other half unpaired. EEG was then recorded as they listened to the sounds, with participants in the involuntary group performing a sound localization cover task, and those in the voluntary group additionally attempting to recall the associated pictures. Participants later reported which sounds brought the paired picture to mind during the localization task. Reaction times on the localization task were slower for voluntary than involuntary retrieval and for paired than unpaired sounds, possibly reflecting increased attentional demands of voluntary retrieval and interference from reactivation of the associated pictures respectively. For the EEG analyses, young adults showed greater alpha event-related desynchronization (ERD) during voluntary than involuntary retrieval at frontal and occipital sites, while older adults showed pronounced alpha ERD regardless of intention. Additionally, older adults showed greater ERD for paired than unpaired sounds at occipital sites, likely reflecting visual reactivation of the associated pictures. Young adults did not show this alpha ERD memory effect. Taken together, these data suggest that involuntary memory is largely preserved with age, but this may be due to older adults' greater recruitment of top-down control even when demand for such control is limited.  相似文献   
7.
International Journal of Clinical Pharmacy - Background Drug-related problems (DRP) following hospital discharge may cause morbidity, mortality and hospital re-admissions. It is unclear whether a...  相似文献   
8.
9.
10.
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