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   1468篇
  免费   56篇
  国内免费   4篇
耳鼻咽喉   2篇
儿科学   34篇
妇产科学   39篇
基础医学   221篇
口腔科学   35篇
临床医学   157篇
内科学   350篇
皮肤病学   15篇
神经病学   123篇
特种医学   63篇
外国民族医学   1篇
外科学   120篇
综合类   9篇
一般理论   1篇
预防医学   190篇
眼科学   6篇
药学   59篇
肿瘤学   103篇
  2024年   3篇
  2023年   18篇
  2022年   25篇
  2021年   41篇
  2020年   26篇
  2019年   48篇
  2018年   39篇
  2017年   31篇
  2016年   31篇
  2015年   54篇
  2014年   48篇
  2013年   69篇
  2012年   139篇
  2011年   136篇
  2010年   68篇
  2009年   52篇
  2008年   115篇
  2007年   121篇
  2006年   77篇
  2005年   64篇
  2004年   61篇
  2003年   64篇
  2002年   59篇
  2001年   13篇
  2000年   10篇
  1999年   11篇
  1998年   11篇
  1997年   7篇
  1996年   12篇
  1995年   9篇
  1994年   6篇
  1993年   6篇
  1992年   8篇
  1991年   5篇
  1990年   3篇
  1989年   7篇
  1988年   9篇
  1987年   7篇
  1986年   4篇
  1985年   2篇
  1984年   1篇
  1983年   1篇
  1982年   2篇
  1981年   2篇
  1979年   2篇
  1977年   1篇
排序方式: 共有1528条查询结果,搜索用时 15 毫秒
21.
The eradication of inhibitory antibodies in patients with haemophilia A can be accomplished by frequent administration of high or intermediate doses of factor VIII (FVIII), so-called immune tolerance induction (ITI). This study monitored the distribution of IgG subclasses of anti-FVIII antibodies during ITI. FVIII-specific antibodies of subclass IgG1 were detected in all inhibitor patients tested, anti-FVIII IgG4 in 16, IgG2 in 10 and IgG3 in one of 20 patients analysed. Levels of anti-FVIII IgG1 and IgG4 correlated well with inhibitor titres as measured by Bethesda assay. In low-titre inhibitor patients, anti-FVIII antibodies consisted primarily of subclass IgG1 whereas, anti-FVIII antibodies of subclass IgG4 were more prominent in patients with high titre inhibitors who needed prolonged treatment or who failed ITI. Longitudinal analysis of 14 patients undergoing ITI revealed that the relative contribution of IgG subclasses was constant for most of the patients analysed. In two patients, the relative contribution of IgG4 increased during ITI. Overall, our findings document the distribution and dynamics of anti-FVIII IgG subclasses during ITI. Future studies will need to address whether monitoring the relative contribution of anti-FVIII subclasses IgG1 and IgG4 may be useful for the identification of patients who are at risk of failing ITI.  相似文献   
22.
Die Diabetologie - Deutschland ist ein Einwanderungsland und 2019 hatte mehr als jede vierte hier lebende Person einen sog. Migrationshintergrund. Bei dieser statistisch definierten Gruppe handelt...  相似文献   
23.

Background and objectives

Low trait self-control constitutes a core criterion in various psychiatric disorders. Personality traits such as low self-control are mostly indexed by self-report measures. However, several theorists emphasized the importance of differentiating between explicit and implicit indices of personality traits, Therefore, the present study examined the unique predictive validity of an implicit measure of trait self-control for spontaneous dysfunctional behavior.

Methods

As a measure of implicit trait self-control, we used an irrelevant feature task: a speeded reaction time task comprising a task-relevant stimulus feature (i.e., capital vs. lower case letter type) and a task-irrelevant feature (high vs. low self-control word type). The irrelevant feature had to be ignored, while participants (n = 34) responded to the relevant stimulus feature. However, their response was either congruent or incongruent with the irrelevant stimulus feature, resulting in facilitated or deteriorated task performance. As indicators of trait-related spontaneous dysfunctional behavior, we included indices of frustration tolerance and the preference for short-term reward over meeting long-term goals. We also included two explicit measures of trait self-control: a self-report questionnaire and an explicit self-relevance rating of the implicit task stimuli.

Results

Specifically the implicit measure of trait self-control showed predictive validity for the target self-control behaviors.

Limitations

The predictive validity of implicit measures of personality traits requires further study in larger, non-student samples.

Conclusions

As predicted, the implicit measure of trait self-control showed superior predictive power for spontaneous trait-related behavior. This finding points to the relevance of complementing the routinely used self-report measures with implicit measures of trait self-control.  相似文献   
24.
Plants in dense vegetation compete for resources, including light, and optimize their growth based on neighbor detection cues. The best studied of such behaviors is the shade-avoidance syndrome that positions leaves in optimally lit zones of a vegetation. Although proximate vegetation is known to be sensed through a reduced ratio between red and far-red light, we show here through computational modeling and manipulative experiments that leaves of the rosette species Arabidopsis thaliana first need to move upward to generate sufficient light reflection potential for subsequent occurrence and perception of a reduced red to far-red ratio. This early hyponastic leaf growth response is not induced by known neighbor detection cues under both climate chamber and natural sunlight conditions, and we identify a unique way for plants to detect future competitors through touching of leaf tips. This signal occurs before light signals and appears to be the earliest means of above-ground plant-plant signaling in horizontally growing rosette plants.  相似文献   
25.
26.
27.
This 13-year randomized clinical trial compared the clinical effectiveness of two three-step etch-and-rinse adhesives in combination with a hybrid, stiffer composite versus a micro-filled, more flexible composite. The influence of composite stiffness on the clinical performance of one of the adhesives was assessed as well. One hundred and forty-two non-carious cervical lesions were restored with composites with contrasting stiffness. Seventy-one patients randomly received two cervical restorations placed following two out of three adhesive procedures: (1) the three-step etch-and-rinse adhesive Permaquick applied with the stiff micro-hybrid composite Amelogen Hybrid (PMQ-H, Ultradent), (2) Permaquick applied with the more flexible micro-filled Amelogen Microfill (PMQ-M, Ultradent), or (3) the “gold-standard” three-step etch-and-rinse adhesive Optibond FL applied with the micro-hybrid composite Prodigy (OFL-P, Kerr). The restorations were evaluated after 6 months, 1, 2, 3, 5, 7, and 13 years of clinical service regarding their retention, marginal integrity and discoloration, caries occurrence, preservation of tooth vitality, and post-operative sensitivity. Retention loss, severe marginal defects, and/or discoloration that needed intervention (repair or replacement) and the occurrence of caries were considered as clinical failures. The recall rate at 13 years was 77%. Bond degradation after 13 years was mainly characterized by a further increase in the presence of small but clinically acceptable marginal defects and superficial marginal discoloration. Twelve percent of the OFL-P restorations were clinically unacceptable. In the PMQ group, 22% of the PMQ-M restorations and 26% of the PMQ-H restorations needed repair or replacement. Regarding the clinical failure rate, Optibond FL scored significantly better than Permaquick (McNemar; p = 0.015). No statistically significant differences were found between the micro-filled and the hybrid composite for each of the parameters evaluated (McNemar, p > 0.05). After 13 years of clinical functioning, the clinical effectiveness of the three adhesive/composite combinations remained highly acceptable.  相似文献   
28.
29.
30.
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