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   1461篇
  免费   53篇
  国内免费   8篇
耳鼻咽喉   32篇
儿科学   25篇
妇产科学   18篇
基础医学   100篇
口腔科学   21篇
临床医学   119篇
内科学   318篇
皮肤病学   19篇
神经病学   82篇
特种医学   126篇
外科学   410篇
综合类   35篇
一般理论   2篇
预防医学   45篇
眼科学   37篇
药学   51篇
中国医学   10篇
肿瘤学   72篇
  2025年   1篇
  2024年   21篇
  2023年   16篇
  2022年   35篇
  2021年   50篇
  2020年   36篇
  2019年   74篇
  2018年   52篇
  2017年   31篇
  2016年   43篇
  2015年   39篇
  2014年   91篇
  2013年   74篇
  2012年   120篇
  2011年   121篇
  2010年   61篇
  2009年   31篇
  2008年   89篇
  2007年   120篇
  2006年   88篇
  2005年   80篇
  2004年   67篇
  2003年   58篇
  2002年   51篇
  2001年   8篇
  2000年   6篇
  1999年   10篇
  1998年   6篇
  1997年   5篇
  1996年   4篇
  1995年   4篇
  1994年   4篇
  1993年   1篇
  1992年   1篇
  1991年   2篇
  1989年   1篇
  1988年   4篇
  1987年   2篇
  1984年   1篇
  1983年   1篇
  1981年   3篇
  1980年   1篇
  1979年   2篇
  1975年   2篇
  1974年   2篇
  1973年   1篇
  1972年   1篇
  1964年   1篇
排序方式: 共有1522条查询结果,搜索用时 15 毫秒
61.
62.
    

Background

No‐reflow is associated with a poor prognosis in STEMI patients. There are many factors and mechanisms that contribute to the development of no‐reflow, including age, reperfusion time, a high thrombus burden, Killip class, long stent use, ejection fraction ≤40, and a high Syntax score. In this study, we aimed to evaluate the parameters associated with no‐reflow prediction by creating a new scoring system.

Methods

The study included 515 consecutive STEMI patients who underwent PCI; 632 STEMI patients who had undergone PCI in another center were included in the external validation of the scoring system. The correlations between 1‐year major adverse cardiac events and low/high risk score were assessed.

Results

In this study, seven independent variables were used to build a risk score for predicting no‐reflow. The predictors of no‐reflow are age, EF ≤40, SS ≥22, stent length ≥20, thrombus grade ≥4, Killip class ≥3, and pain‐balloon time ≥4 h. In the derivation group, the optimal threshold score for predicting no‐reflow was >10, with a 75% sensitivity and 77.7% specificity (Area under the curve (AUC) = 0.809, 95%CI: 0.772‐0.842, P < 0.001). In the validation group, AUC was 0.793 (95%CI: 0.760‐0.824, P < 0.001).

Conclusion

This new score, which can be calculated in STEMI patients before PCI and used to predict no‐reflow in STEMI patients, may help physicians to estimate the development of no‐reflow in the pre‐PCI period.  相似文献   
63.
         下载免费PDF全文
AIM: To compare the peripapillary retinal nerve fiber layer (RNFL) thickness measured via optical coherence tomography (OCT) between different groups of myopia severity and controls.METHODS: This was a prospective cross-sectional study. All subjects underwent a full ophthalmic examination, refraction, visual field analysis and A-scan biometry. Myopic patients were classified as low myopia (LM) [spherical equivalent (SE) from greater than -0.5 D, up to -3.0 D], moderate myopia (MM; SE greater than -3.0 D, up to -6.0 D) and high myopia (HM; SE greater than -6.0 D). The control group consisted of emmetropic (EM) patients (SE from +0.5 D to -0.5 D). A Zeiss Cirrus HD-OCT machine was used to measure the peripapillary RNFL thickness of both eyes of each subject. The mean peripapillary RNFL thickness between groups was compared using both analysis of variance and analysis of covariance.RESULTS: A total of 403 eyes of 403 subjects were included in this study. The mean age was 31.48±10.23y. There were 180 (44.7%) eyes with EM, 124 (30.8%) with LM, 73 (18.1%) with MM and 26 (6.5%) with HM. All groups of myopia severity had a thinner average RNFL than the EM group, but after controlling for gender, age, and axial eye length, only the HM group differed significantly from the EM group (P=0.017). Likewise, the superior, inferior and nasal RNFL was thinner in all myopia groups compared to controls, but after controlling for confounders, only the inferior quadrant RNFL was significantly thinner in the HM group, when compared to the EM group (P=0.017).CONCLUSION: The average and inferior quadrant RNFL is thinner in highly myopic eyes compared to emmetropic eyes. Refractive status must be taken into consideration when interpreting the OCT of myopic patients, as RNFL thickness varies with the degree of myopia.  相似文献   
64.
    
The study evaluated the effect of commercial preparation of deltamethrin, Butox®, and fluoride (F?) co-exposure on the brain antioxidant status and cholinesterase activity in rats. Group A was untreated. Group B was gavaged Butox®, providing deltamethrin at the dose rate of 1.28?mg per kg body weight per day. Group C was administered F?, as NaF, in drinking water providing 20?ppm F?. Group D received both deltamethrin and F? at the same dosages as groups B and C, respectively. Although, glutathione S-transferase activity was induced only in Butox® alone treated group, the activities of superoxide dismutase and catalase were inhibited in all treatment groups when compared to the control group. Elevated lipid peroxidation was observed in the groups exposed to F?. The activity of erythrocyte acetylcholinesterase (AChE) was inhibited in Butox® treated groups, whereas brain AChE activity was inhibited in all treatment groups. In conclusion, both deltamethrin (given as Butox®) and F? inhibit AChE activity and produce oxidative stress in brain with F? producing more oxidative damage. However, compared to the individual exposures, the co-exposure of these chemicals does not produce any exacerbated alteration in these biochemical parameters.  相似文献   
65.
66.
67.
68.
69.
70.
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