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   1851篇
  免费   82篇
  国内免费   4篇
耳鼻咽喉   9篇
儿科学   78篇
妇产科学   22篇
基础医学   150篇
口腔科学   39篇
临床医学   125篇
内科学   345篇
皮肤病学   155篇
神经病学   100篇
特种医学   51篇
外科学   403篇
综合类   17篇
一般理论   1篇
预防医学   49篇
眼科学   106篇
药学   145篇
中国医学   2篇
肿瘤学   140篇
  2024年   2篇
  2023年   32篇
  2022年   61篇
  2021年   134篇
  2020年   66篇
  2019年   85篇
  2018年   98篇
  2017年   51篇
  2016年   83篇
  2015年   72篇
  2014年   102篇
  2013年   113篇
  2012年   178篇
  2011年   149篇
  2010年   91篇
  2009年   67篇
  2008年   89篇
  2007年   78篇
  2006年   68篇
  2005年   51篇
  2004年   60篇
  2003年   54篇
  2002年   36篇
  2001年   8篇
  2000年   6篇
  1999年   17篇
  1998年   18篇
  1997年   13篇
  1996年   4篇
  1995年   3篇
  1991年   2篇
  1990年   5篇
  1989年   3篇
  1988年   2篇
  1987年   3篇
  1986年   3篇
  1985年   2篇
  1983年   3篇
  1981年   3篇
  1979年   3篇
  1976年   1篇
  1975年   1篇
  1973年   1篇
  1972年   4篇
  1970年   1篇
  1969年   1篇
  1966年   2篇
  1936年   1篇
  1931年   2篇
  1927年   2篇
排序方式: 共有1937条查询结果,搜索用时 17 毫秒
41.
42.
The purpose of this study was to compare the outcomes of cementless primary total hip arthroplasty (THA) in sickle cell patients compared to the remaining cohort of osteonecrosis patients who did not have this disease. Thirty-two sickle cell patients (42 hips) who had a mean age of 37 years and mean follow-up of 7.5 years (range, 5–11 years) were compared to 87 non-sickle cell osteonecrosis patients (102 hips) who had mean age of 43 years and mean follow-up of 7 years (range, 3–10.5 years). Outcomes evaluated included implant survivorship, Harris hip scores, complication rates, radiographic outcomes, and Short Form-(SF-36) health questionnaire. There were no significant differences in aseptic implant survivorship (95 vs. 97%), Harris hip scores (87 vs. 88 points), SF-36 score, or radiographic findings between the two patient cohorts. In light of these findings, we believe that the outcomes of THA improved in sickle cell patients with optimized medical management and the use of cementless prosthetic devices.  相似文献   
43.
44.
45.

Background:

Data is scarce on prevalence of extracranial carotid atherosclerosis (ECA) in strokes <50 years and its association with lifestyle factors.

Objective:

Study role of (a) ECA in non-cardio-embolic anterior circulation young strokes, and (b) smoking and alcohol in ECA.

Materials and Methods:

Cardiovascular risk factors and evidence of ECA on carotid doppler ultrasound (CDUS) was evaluated in an one-year preliminary cross-sectional study of consecutive strokes between 20 years and 49 years. Females were excluded.

Results:

There were 46 male strokes (mean age 38.26 yrs), 17.39% had hypertension, 2.23% had coronary artery disease; none was diabetic. Tobacco users and alcohol consumers were 24/46 (52.17%) cases each. ECA was found in 14/46 (30.44%) cases. Seven of these 14 (50%) i.e., 7/46 cases (15.21%) had carotid occlusion, four had <50%, three had >70% stenosis. ‘Smoking and smokeless tobacco use’ was found in 71.42% (10/14) symptomatic carotid lesions compared to 43.75% (14/32) strokes without carotid lesions. Prevalence odds ratio for tobacco use and ECA was 3.21 (95% CI: 0.83-12.44) while that of alcohol and ECA was 1.33 (95% CI: 0.38-4.72).

Conclusion:

Prevalence of ECA in strokes <50 years was high due to lifestyle factors which predispose to atherosclerosis at younger age.Key Words: Alcohol, extracranial carotid atherosclerosis, lifestyle factors, smoking, young stroke  相似文献   
46.
Two alkyl substituted triaryl-cyclopentadienyl ligands [4,4′-(4-phenylcyclopenta-1,3-diene-1,2-diyl)bis(methylbenzene) (1) and 4,4′,4′′-(cyclopenta-1,3-diene-1,2,4-triyl)tris(methylbenzene) (2)] have been synthesized via cross-aldol condensation followed by Zn-dust mediated cyclization and acid catalyzed dehydration reactions. The fluorescence properties of 1 and 2 have been studied in solution and solid state. The ligands exhibited aggregation-induced emission enhancement (AIEE) in THF/water solution. 1 and 2 have been found to be significantly more fluorescent in the solid state than in their respective solutions. This phenomenon can be attributed to the strong intermolecular CH⋯π interactions present in 1 and 2 which leads to the tight packing of molecules in their solid-state. Both 1, 2 and their corresponding anions have been studied by theoretical calculations. Ligands 1 and 2 have been shown to react with anhydrous DyCl3 in the presence of potassium metal at high temperature to afford two fluorescent chloride-bridged tetra-nuclear mixed potassium–dysprosium metallocenes [(Me2Cp)4Dy2IIICl4K2]·3.5(C7H8) (5) and [(Me3Cp)4Dy2IIICl4K2]·3(C7H8) (6), respectively in good yields.

Alkyl substituted triaryl-cyclopentadienyl ligands with aggregation-induced emission enhancement (AIEE) properties and their applications in the syntheses of novel chloride bridged tetra-nuclear mixed potassium–dysprosium metallocenes.  相似文献   
47.
48.
49.
50.
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