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   13633篇
  免费   677篇
  国内免费   80篇
耳鼻咽喉   181篇
儿科学   287篇
妇产科学   271篇
基础医学   1664篇
口腔科学   736篇
临床医学   1062篇
内科学   3294篇
皮肤病学   245篇
神经病学   1187篇
特种医学   300篇
外科学   2189篇
综合类   72篇
一般理论   7篇
预防医学   949篇
眼科学   266篇
药学   787篇
中国医学   50篇
肿瘤学   843篇
  2024年   14篇
  2023年   127篇
  2022年   268篇
  2021年   496篇
  2020年   282篇
  2019年   380篇
  2018年   467篇
  2017年   333篇
  2016年   329篇
  2015年   396篇
  2014年   579篇
  2013年   727篇
  2012年   1182篇
  2011年   1185篇
  2010年   649篇
  2009年   593篇
  2008年   945篇
  2007年   919篇
  2006年   832篇
  2005年   783篇
  2004年   681篇
  2003年   574篇
  2002年   564篇
  2001年   80篇
  2000年   76篇
  1999年   89篇
  1998年   109篇
  1997年   78篇
  1996年   62篇
  1995年   58篇
  1994年   49篇
  1993年   43篇
  1992年   41篇
  1991年   42篇
  1990年   25篇
  1989年   23篇
  1988年   19篇
  1987年   23篇
  1986年   31篇
  1985年   22篇
  1984年   19篇
  1983年   13篇
  1981年   18篇
  1980年   19篇
  1979年   15篇
  1977年   14篇
  1976年   10篇
  1975年   13篇
  1974年   15篇
  1972年   10篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
This meta-analysis focuses on the accuracy of upgrading to clinically significant prostate cancer (PCa) by multiparametric magnetic resonance imaging-targeted biopsy (MRI-TB) versus systematic biopsy (SB). We searched the Medline, Embase, Cochrane Central Register of Controlled Trials, Web of Science, Scopus, and Literatura Latino Americana em Ciências da Saúde databases through January 2020 for comparative, retrospective/prospective, paired-cohort, and randomized clinical trials with paired comparisons. The population consisted of patients with low-risk PCa in active surveillance with at least 1 index lesion on imaging. We evaluated the quality of evidence by using the Quality Assessment of Diagnostic Accuracy Studies-2 score. Group comparisons considered the differences between the area under the curve summary receiver operating characteristic curve in a 2-tailed method. We also compared the positive predictive value of the best single method (MRI-TB or SB) and the referral study test (combined biopsy, a combination of MRI-TB and SB). The meta-analysis included 6 studies enrolling 741 patients. The pooled sensitivity for the 2 groups was 0.79 (95% confidence interval, 0.74-0.83; I2 = 75%) and 0.67 (95% confidence interval, 0.63-0.74; I2 = 55.4%), respectively. The area under the curve for the MRI-TB and SB groups were 0.99 and 0.92 (P < .001), respectively. The positive predictive value for the MRI-TB and combined biopsy groups were similar. The accumulated evidence suggests better results for MRI-TB compared with SB. Therefore, use of MRI-TB alone may be preferable in patients in active surveillance harboring low-risk PCa.  相似文献   
3.
Journal of Digital Imaging - Vertebral Compression Fracture (VCF) occurs when the vertebral body partially collapses under the action of compressive forces. Non-traumatic VCFs can be secondary to...  相似文献   
4.
5.
6.
7.
OBJECTIVES: The aim of this study is to evaluate the effect of ZnSO(4) addition to a conventional glass ionomer and a resin-modified glass ionomer on solubility, flexural strength, zinc and fluoride (F) release, and Streptococcus mutans growth inhibition. METHODS: 5 or 10% ZnSO(4) was added to Vitremer and Ketac-Fil powders. Solubility test was performed based on ISO 7489. Flexural strength was determined by 3-point bending test based on ISO 4049. Zn release/uptake was determined by atomic emission spectrometry; F release/uptake was measured using a F-specific electrode. Both release measurements were performed for 15 d before and 15 d after recharging. Antibacterial test was conducted according to agar plate methods against S. mutans, by measuring the inhibition halos in 1-h and 15-d specimens. Data were analyzed by ANOVA. RESULTS: Solubility increased with higher ZnSO(4) content, but remained below the ISO 7489 limit. Flexural strength was not affected by ZnSO(4) addition, and Vitremer performed better than Ketac-Fil. The control materials released no zinc. Vitremer with 10% ZnSO(4) released the highest amount of zinc. Fluoride release was similar for Ketac-Fil and Vitremer. In both cases, the highest amounts were released in the first 24 h. The growth inhibition halo of S. mutans was similar for both materials with highest content of ZnSO(4) and occurred only with 1-h specimens. SIGNIFICANCE: Zinc addition decreased microorganisms growth and improved fluoride release, without significantly affecting the materials' flexural strength and solubility.  相似文献   
8.
9.
结果 髌股关节的压力与应力随膝关节屈曲角度的增加而升高,随膝关节屈曲角度的减小而降低(图3~8).不同膝关节屈曲角度下弓步变化和跨步变化的髌股关节压力见表1.  相似文献   
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