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   8624篇
  免费   697篇
  国内免费   34篇
耳鼻咽喉   46篇
儿科学   286篇
妇产科学   179篇
基础医学   1269篇
口腔科学   314篇
临床医学   715篇
内科学   2189篇
皮肤病学   259篇
神经病学   676篇
特种医学   282篇
外国民族医学   4篇
外科学   1176篇
综合类   53篇
一般理论   2篇
预防医学   848篇
眼科学   150篇
药学   409篇
中国医学   60篇
肿瘤学   438篇
  2023年   57篇
  2022年   102篇
  2021年   277篇
  2020年   168篇
  2019年   259篇
  2018年   331篇
  2017年   208篇
  2016年   223篇
  2015年   206篇
  2014年   292篇
  2013年   403篇
  2012年   509篇
  2011年   596篇
  2010年   346篇
  2009年   298篇
  2008年   443篇
  2007年   448篇
  2006年   450篇
  2005年   376篇
  2004年   348篇
  2003年   357篇
  2002年   298篇
  2001年   256篇
  2000年   286篇
  1999年   245篇
  1998年   84篇
  1997年   60篇
  1996年   69篇
  1995年   57篇
  1994年   52篇
  1993年   58篇
  1992年   133篇
  1991年   127篇
  1990年   119篇
  1989年   79篇
  1988年   81篇
  1987年   65篇
  1986年   72篇
  1985年   78篇
  1984年   49篇
  1983年   36篇
  1982年   29篇
  1979年   20篇
  1978年   24篇
  1973年   23篇
  1972年   23篇
  1971年   23篇
  1970年   26篇
  1968年   18篇
  1967年   19篇
排序方式: 共有9355条查询结果,搜索用时 343 毫秒
11.
12.
13.
14.
Objective: M-mode and 2D have been proposed for evaluating fetal myocardial thickness. However, studies comparing the performance of both modalities are lacking. We aimed to compare 2D versus M-mode reproducibility for assessing myocardial wall thicknesses.

Methods: A prospective study including 45 healthy fetuses from low-risk pregnancies evaluated between 18 and 41 weeks of gestation. Left and right ventricular free-wall and septal myocardial thicknesses were measured at end-diastole (ED) and end-systole (ES) in transverse 4-chamber view using 2D and M-mode. Intra- and interobserver reproducibility was evaluated by the concordance correlation coefficient (CCC). Both techniques were compared by t-test of the CCC.

Results: 2D and M-mode demonstrated excellent and similar intraobserver repeatability, with the best concordance in ES septal thickness (M-mode CCC 0.956 versus 2D-mode CCC 0.914). Interobserver reproducibility demonstrated also a high concordance, optimal in ES left ventricular free wall (M-mode 0.925 versus 2 D 0.855). Comparison of both techniques demonstrated a high concordance in all measurements, except for ED septal thickness with better reproducibility using M-mode (CCC 0.954 versus 0.847, p?=?.017).

Conclusions: 2D and M-mode can be used in a reproducible manner for measuring fetal myocardial thickness, with a slightly better performance of M-mode for assessing ED septal wall thickness.  相似文献   
15.
16.
17.
18.
19.
In this paper we discuss the effects of nonsteroidal antiinflammatory drugs on proteinuria and the specific risks of these drugs in patients with nephrotic syndrome. We summarize the results of a prospective uncontrolled trial of meclofenamate in severe steroid-resistant nephrotic syndrome secondary to focal glomerular sclerosis and idiopathic membranous nephropathy. This study examined the effect of meclofenamate on proteinuria, serum albumin levels, serum cholesterol, serum triglycerides, renal function, BP, liver function tests, and hematologic values. We also sought and evaluated adverse reactions due to this medication. We offer some suggestions for selective use and careful supervision of NSAIDs in the nephrotic syndrome.  相似文献   
20.
Background  Surgical procedures enhance production of pro- and anti-inflammatory cytokines and angiogenic factors that play a pivotal role in the immunological response to surgical trauma and take part in the pathogenesis of tumor growth and adhesions formation. The purpose of the study was to access the influence of low-pressure CO2 pneumoperitoneum on the inflammatory and angiogenic responses during the postoperative period after laparoscopy. Methods  The study group consisted of 40 patients, operated on due to cholelithiasis using standard-pressure (n = 20) and low-pressure (n = 20) CO2 pneumoperitoneum. Serum concentration of interleukin (IL)-6, IL-8, IL-10, vascular endothelial growth factor (VEGF)-A, and endostatin were measured before and at 6, 24, and 48 h after surgery with commercially available enzyme-linked immunosorbent assay (ELISA). Results  Concentrations of IL-6 increased significantly after the operations in both groups. No differences were observed between the groups in regards to IL-6, IL-8, and IL-10 levels. Concentrations of VEGF-A measured at 6 and 48 h were significantly lower in patients who underwent laparoscopies performed with low-pressure pneumoperitoneum. No significant variations were observed in endostatin serum concentration. Concentrations of the studied parameters were not influenced by duration of surgery or by age, gender, or body mass index (BMI) of the patients. Conclusions  The results obtained in our study do not show any significant differences between studied operative procedures with regards to systemic inflammatory response. Changes in the concentrations of VEGF-A and endostatin observed in the studied population may suggest this technique is more favorable with regards to angiogenesis process intensity, along with all its consequences and implications.  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