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   815篇
  免费   52篇
  国内免费   3篇
耳鼻咽喉   18篇
儿科学   49篇
妇产科学   36篇
基础医学   75篇
口腔科学   19篇
临床医学   90篇
内科学   182篇
皮肤病学   41篇
神经病学   71篇
特种医学   21篇
外科学   130篇
综合类   15篇
预防医学   23篇
眼科学   27篇
药学   46篇
中国医学   3篇
肿瘤学   24篇
  2023年   8篇
  2022年   11篇
  2021年   27篇
  2020年   14篇
  2019年   14篇
  2018年   25篇
  2017年   22篇
  2016年   43篇
  2015年   46篇
  2014年   46篇
  2013年   40篇
  2012年   58篇
  2011年   71篇
  2010年   41篇
  2009年   36篇
  2008年   59篇
  2007年   70篇
  2006年   59篇
  2005年   54篇
  2004年   37篇
  2003年   32篇
  2002年   26篇
  2001年   5篇
  2000年   5篇
  1999年   5篇
  1998年   2篇
  1997年   1篇
  1996年   2篇
  1992年   2篇
  1991年   2篇
  1990年   4篇
  1986年   1篇
  1980年   1篇
  1977年   1篇
排序方式: 共有870条查询结果,搜索用时 16 毫秒
1.
2.
3.
4.
Potent inhibition of HIV-1 entry by (s4dU)35   总被引:2,自引:0,他引:2  
  相似文献   
5.
BACKGROUND: Glutathione-S-tranferase (GST) is the part of the key phase II detoxifying enzyme system. Many studies have investigated the role of GSTM1 and GSTT1 gene polymorphisms in endometriosis. Although GSTP1 was found to be one of the most abundant types of GST in genital system, there are insufficient data about the importance of the role of GSTP1 gene polymorphism in endometriosis. METHODS: This case-control study involved 150 patients with endometriosis and 150 controls. The frequency of GSTP1 single nucleotide polymorphisms was evaluated using PCR and melting curve analysis. RESULTS: The proportion of GSTP1 ile/ile tended to be higher in patients with endometriosis than control group, although the difference was not significant [odds ratio (OR)=1.53; 95% confidence interval (CI)=0.95-2.46]. In contrast, GSTP1 val/val was significantly higher in control patients and seems protective for endometriosis (OR=0.10; 95% CI=0.02-0.42). CONCLUSION: The results of this study suggest that GSTP1 polymorphism might modulate the risk of endometriosis with significantly decreased risk for GSTP1 val/val and marginally increased risk for GSTP1 ile/ile. Further studies on not only the disease processes but also normal distribution of the enzyme in female genital tract may provide better understanding about the role of GST types and their polymorphs in endometriosis.  相似文献   
6.
When tracking moving visual stimuli, primates orient their visual axis by combining two kinds of eye movements, smooth pursuit and saccades, that have very different dynamics. Yet, the mechanisms that govern the decision to switch from one type of eye movement to the other are still poorly understood, even though they could bring a significant contribution to the understanding of how the CNS combines different kinds of control strategies to achieve a common motor and sensory goal. In this study, we investigated the oculomotor responses to a large range of different combinations of position error and velocity error during visual tracking of moving stimuli in humans. We found that the oculomotor system uses a prediction of the time at which the eye trajectory will cross the target, defined as the "eye crossing time" (T(XE)). The eye crossing time, which depends on both position error and velocity error, is the criterion used to switch between smooth and saccadic pursuit, i.e., to trigger catch-up saccades. On average, for T(XE) between 40 and 180 ms, no saccade is triggered and target tracking remains purely smooth. Conversely, when T(XE) becomes smaller than 40 ms or larger than 180 ms, a saccade is triggered after a short latency (around 125 ms).  相似文献   
7.
Micro-centrifugation (MC) at 6500 r.p.m. (3352 g) has not beenused previously for spermatozoal concentration and subsequentfertilization. We investigated MC for micro-insemination spermatozoaltransfer (MIST) of human spermatozoa from normal donors intohamster oocytes. MC resulted in reduced penetration of hamsteroocytes, both after MIST [77.4% (41/53) versus 87.8% (43/49)for control; NS] and after exposure to zona-free hamster oocytes[60.8% (79/130) versus 72.7% (88/121) for control; P < 0.05].However, MIST under the zona resulted in better incorporationof sperm nuclei when compared with zona-free hamster oocytes,for spermatozoa exposed to micro-centrifugation (77.4 versus60.8%, P < 0.05) and controls (87.8 versus 72.7%, P <0.05). Polyspermy was higher after MIST [22.0% (9/41) versus13.9% (11/79); NS] for MC + , and [25.6% (11/43) versus 13.6%(12/88); NS] for MC-. We conclude that MC does have a negative,but minimal effect on the fertility of human spermatozoa withrespect to hamster oocytes.  相似文献   
8.
Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz - Erste Studien heben den Migrationshintergrund von Menschen in Deutschland als eigenständigen Risikofaktor für eine...  相似文献   
9.
10.
Salbutamol or mist in acute bronchiolitis   总被引:1,自引:0,他引:1  
Abstract Background : The role of bronchodilators in the treatment of bronchiolitis remains controversial.
Methods : A double-blind, placebo controlled trial was performed to evaluate the clinical response to nebulized salbutamol. One hundred and fifty-six infants aged between 7 weeks and 24 months who had had an episode of wheezing and other signs and symptoms of bronchiolitis were randomized to three groups as follows: (i) nebulized salbutamol was administered to 52 patients in group I at a dose of 0.15 mg/kg in 2 mL saline; (ii) saline was nebulized to 52 patients in group II and (iii) in group III 52 patients received mist in a tent. All three groups were administered oxygen during the procedures. Treatment was repeated with the same agent after 30 min if the respiratory score was 5 or more. Respiratory rate, heart rate, oxygen saturation and presence of cyanosis, wheezing, retractions were recorded before and after each treatment.
Results : The decrease in the respiratory score was 5.2 ± 1.8, 0.82 ± 2.4 and 1.7 ± 1.3 in group I, II and III, respectively. The decrease in group I was significantly higher than in the other groups. Heart rate was similar between groups. Oxygen saturation decreased in group I without reaching statistical significance.
Conclusions: Salbutamol was shown to be effective and safe in the treatment of acute bronchiolitis.  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