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   4459篇
  免费   183篇
  国内免费   38篇
耳鼻咽喉   130篇
儿科学   215篇
妇产科学   128篇
基础医学   311篇
口腔科学   157篇
临床医学   337篇
内科学   1089篇
皮肤病学   80篇
神经病学   302篇
特种医学   185篇
外科学   982篇
综合类   91篇
一般理论   1篇
预防医学   209篇
眼科学   100篇
药学   169篇
中国医学   9篇
肿瘤学   185篇
  2023年   39篇
  2022年   55篇
  2021年   126篇
  2020年   70篇
  2019年   100篇
  2018年   126篇
  2017年   74篇
  2016年   144篇
  2015年   132篇
  2014年   162篇
  2013年   259篇
  2012年   348篇
  2011年   334篇
  2010年   181篇
  2009年   159篇
  2008年   333篇
  2007年   348篇
  2006年   359篇
  2005年   318篇
  2004年   287篇
  2003年   220篇
  2002年   188篇
  2001年   19篇
  2000年   19篇
  1999年   16篇
  1998年   6篇
  1997年   6篇
  1996年   10篇
  1995年   5篇
  1992年   17篇
  1991年   7篇
  1990年   11篇
  1989年   7篇
  1988年   15篇
  1987年   13篇
  1986年   16篇
  1985年   24篇
  1984年   12篇
  1983年   8篇
  1982年   9篇
  1981年   6篇
  1980年   6篇
  1979年   13篇
  1978年   9篇
  1977年   5篇
  1976年   5篇
  1974年   8篇
  1972年   8篇
  1969年   6篇
  1968年   6篇
排序方式: 共有4680条查询结果,搜索用时 578 毫秒
41.
42.
43.
Methods:Data on 11 robot-assisted laparoscopic partial nephrectomies performed by using our technique from February 2015 through June 2015 were retrospectively analyzed. The robotic platform used was DaVinci Xi (Intuitive Surgical, Inc., Sunnyvale, California, USA) with a 3-arm setup. The AirSeal system (SurgiQuest, Milford, Connecticut, USA) was used as a port allowing simultaneous introduction of 2 instruments for the bedside surgeon, obviating the need for an additional (fourth) robotic arm. A long suction-and-irrigation device and atraumatic grasping forceps were used. Both instruments were introduced through the trocar of the AirSeal system, making simultaneous introduction and use possible. We preferred the long suction-and-irrigation device, because it minimizes collision of the instruments.Results:Mean age and BMI of the patients were 55 ±14.6 y and 29.18 ± 6.85, respectively. Seven tumors were on the right side and 4 were on the left. The mean size of the tumors was 32.45 mm (± 11.31). Surgical time was 132.2 minutes (±37.17), with an estimated blood loss and ischemia time of 103.63 mL (±65.92) and 16.72 minutes (±9.52), respectively. One patient had postoperative bleeding that was resolved without transfusion. The median hospitalization period was 3.9 d (±0.53). Loss of intra-abdominal pressure was not observed, and pressure was stable at 10 mm Hg.Conclusion:The AirSeal System and its valveless trocar eliminated the need for an additional port placement in our series. The technique is feasible, safe, and reproducible; therefore, it may be implemented in selected cases of robot-assisted partial nephrectomies.  相似文献   
44.
45.
46.
Conclusion: A significant association was found of oropharyngeal tularemia with SLC11A1 allele polymorphism (INT4?G/C) and MBL2 C?+?4T (P/Q). These results indicate C allele and Q allele might be a risk factor for the development of oropharyngeal tularemia.

Aim: This study aimed to investigate the relationship of SLC11A1, MBL, and P2X7 gene polymorphism with oropharyngeal tularemia.

Methods: The study included totally 120 patients who were diagnosed with oropharyngeal tularemia. Frequencies of polymorphisms in the following genes were analyzed both in the patient and control groups in the study: SLC11A1 (5’(GT)n Allele 2/3, Int4?G/C, 3’ UTR, D543N G/A), MBL (MBL2 C?+?4T (P/Q), and P2X7 (?762 C/T and 1513 A/C).

Results: Among all polymorphisms that were investigated in this study, SLC11A1 gene showed a significance in the distriburtion of polymorphism allelle frequency at the INT4 region. Frequency of C allele was 54 (28%) in patients with oropharyngeal tularemia, and 31 (13%) in the control group (p?=?0.006 and OR = 1.96 (1.21–3.20)). An association was detected between MBL2 C?+?4T (P/Q) gene polymorphism and oropharyngeal tularemia (p?7 (?762 C/T and 1513 A/C) gene polymorphism and oropharyngeal tularemia in this study (p?>?0.05).  相似文献   
47.
Classical cadherin cell-cell adhesion proteins play key morphogenetic roles during development and are essential for maintaining tissue integrity in multicellular organisms. Classical cadherins bind in two distinct conformations, X-dimer and strand-swap dimer; during cellular rearrangements, these adhesive states are exposed to mechanical stress. However, the molecular mechanisms by which cadherins resist tensile force and the pathway by which they convert between different conformations are unclear. Here, we use single molecule force measurements with an atomic force microscope (AFM) to show that E-cadherin, a prototypical classical cadherin, forms three types of adhesive bonds: catch bonds, which become longer lived in the presence of tensile force; slip bonds, which become shorter lived when pulled; and ideal bonds that are insensitive to mechanical stress. We show that X-dimers form catch bonds, whereas strand-swap dimers form slip bonds. Our data suggests that ideal bonds are formed as X-dimers convert to strand-swap binding. Catch, slip, and ideal bonds allow cadherins to withstand tensile force and tune the mechanical properties of adhesive junctions.  相似文献   
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