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   1854篇
  免费   105篇
  国内免费   13篇
耳鼻咽喉   12篇
儿科学   55篇
妇产科学   43篇
基础医学   240篇
口腔科学   29篇
临床医学   224篇
内科学   494篇
皮肤病学   28篇
神经病学   189篇
特种医学   58篇
外科学   151篇
综合类   6篇
预防医学   146篇
眼科学   36篇
药学   123篇
肿瘤学   138篇
  2024年   2篇
  2023年   23篇
  2022年   43篇
  2021年   76篇
  2020年   54篇
  2019年   63篇
  2018年   61篇
  2017年   50篇
  2016年   52篇
  2015年   67篇
  2014年   89篇
  2013年   106篇
  2012年   159篇
  2011年   140篇
  2010年   95篇
  2009年   91篇
  2008年   135篇
  2007年   127篇
  2006年   120篇
  2005年   99篇
  2004年   100篇
  2003年   76篇
  2002年   68篇
  2001年   10篇
  2000年   6篇
  1999年   10篇
  1998年   14篇
  1997年   7篇
  1996年   7篇
  1995年   8篇
  1994年   4篇
  1993年   1篇
  1992年   4篇
  1984年   1篇
  1983年   1篇
  1978年   1篇
  1975年   1篇
  1973年   1篇
排序方式: 共有1972条查询结果,搜索用时 15 毫秒
1.
A 59-year-old hypertensive male, 1 year after uncomplicatedmitral annuloplasty for regurgitation with MAZE procedure, witha history of chronic obstructive pulmonary disease and repeatedpulmonary  相似文献   
2.
We demonstrate the effect of deep brain stimulation of the ventral intermediate thalamic nucleus on intractable action tremor, in a 72-year-old man suffering from neuropathy associated with monoclonal gammopathy.  相似文献   
3.

Background  

Anti-cyclic citrullinated peptide (anti-CCP) antibodies have been of diagnostic value in Northern European Caucasian patients with rheumatoid arthritis (RA). In these populations, anti-CCP antibodies are associated with the HLA-DRB1 shared epitope. We assessed the diagnostic value of anti-CCP antibodies in Greek patients with RA where the HLA shared epitope was reported in a minority of patients.  相似文献   
4.
5.
Childhood overweight and obesity prevalence has risen dramatically in the past decades, and family-based interventions may be an effective method to improve children’s eating behaviors. This study aimed to evaluate the effectiveness of three different family-based interventions: group-based, individual-based, or by website approach. Parents and school aged overweight or obese children, 8–12 years of age, were eligible for the study. A total of 115 children were randomly allocated in one of the three interventions, and 91 completed the study (79% compliance); Group 1 (n = 36) received group-based interventions by various experts; Group 2 (n = 30) had interpersonal family meetings with a dietitian; and Group 3 (n = 25) received training through a specifically developed website. Anthropometric, dietary, physical activity, and screen time outcomes were measured at baseline and at the end of the study. Within-group comparisons indicated significant improvement in body weight, body mass index (BMI)-z-score, physical activity, and screen time from baseline in all three study groups (p < 0.05). Furthermore, total body fat percentage (%TBF) was also decreased in Groups 2 and 3. Between-group differences varied with body weight and %TBF change, being larger in Group 3 compared to Groups 1 and 2, in contrast to BMI-z-score, screen time, and health behaviors, which were significantly larger in Group 2 than the other two groups. In conclusion, personalized family-based interventions are recommended to successfully improve children’s lifestyle and body weight status.  相似文献   
6.
7.
Background Are follicles where no oocytes are retrieved empty follicles?Methods The levels of estradiol (E2), progesterone (P), testosterone (T), cortisol (F), and prolactin (PRL) of follicular fluids (FF) aspirated individually from 34 randomly selected IVF patients in whom no oocytes were recovered were compared with the respective hormone levels of FF obtained from the same patients when oocytes were retrieved. Two FF without oocytes of a 35th patient in whom no oocytes were retrieved were analyzed.Results Hormones did not differ significantly in the paired samples, while in the two FF of the 35th woman they were in agreement with cystic follicles.Conclusions It is necessary to differentiate aspirated follicles where no oocytes are retrieved from the empty follicle syndrome, which was not observed in the IVF series studied and should be rare in IVF patients.  相似文献   
8.
The involvement of adenosine A(1) and A(2A) receptors in the motor effects of caffeine is still a matter of debate. In the present study, counteraction of the motor-depressant effects of the selective A(1) receptor agonist CPA and the A(2A) receptor agonist CGS 21680 by caffeine, the selective A(1) receptor antagonist CPT, and the A(2A) receptor antagonist MSX-3 was compared. CPT and MSX-3 produced motor activation at the same doses that selectively counteracted motor depression induced by CPA and CGS 21680, respectively. Caffeine also counteracted motor depression induced by CPA and CGS 21680 at doses that produced motor activation. However, caffeine was less effective than CPT at counteracting CPA and even less effective than MSX-3 at counteracting CGS 21680. On the other hand, when administered alone in habituated animals, caffeine produced stronger motor activation than CPT or MSX-3. An additive effect on motor activation was obtained when CPT and MSX-3 were coadministered. Altogether, these results suggest that the motor-activating effects of acutely administered caffeine in rats involve the central blockade of both A(1) and A(2A) receptors. Chronic exposure to caffeine in the drinking water (1.0 mg/ml) resulted in tolerance to the motor effects of an acute administration of caffeine, lack of tolerance to amphetamine, apparent tolerance to MSX-3 (shift to the left of its 'bell-shaped' dose-response curve), and true cross-tolerance to CPT. The present results suggest that development of tolerance to the effects of A(1) receptor blockade might be mostly responsible for the tolerance to the motor-activating effects of caffeine and that the residual motor-activating effects of caffeine in tolerant individuals might be mostly because of A(2A) receptor blockade.  相似文献   
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