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   14800篇
  免费   742篇
  国内免费   69篇
耳鼻咽喉   277篇
儿科学   291篇
妇产科学   365篇
基础医学   2044篇
口腔科学   1338篇
临床医学   970篇
内科学   3042篇
皮肤病学   321篇
神经病学   1021篇
特种医学   337篇
外科学   2154篇
综合类   139篇
一般理论   3篇
预防医学   1408篇
眼科学   284篇
药学   909篇
中国医学   143篇
肿瘤学   565篇
  2023年   96篇
  2022年   271篇
  2021年   484篇
  2020年   279篇
  2019年   374篇
  2018年   501篇
  2017年   286篇
  2016年   340篇
  2015年   500篇
  2014年   646篇
  2013年   718篇
  2012年   1178篇
  2011年   1365篇
  2010年   699篇
  2009年   543篇
  2008年   981篇
  2007年   1027篇
  2006年   908篇
  2005年   784篇
  2004年   762篇
  2003年   601篇
  2002年   575篇
  2001年   211篇
  2000年   244篇
  1999年   177篇
  1998年   74篇
  1997年   53篇
  1996年   47篇
  1995年   42篇
  1994年   33篇
  1993年   41篇
  1992年   87篇
  1991年   67篇
  1990年   69篇
  1989年   69篇
  1988年   47篇
  1987年   46篇
  1986年   45篇
  1985年   40篇
  1984年   28篇
  1983年   32篇
  1982年   18篇
  1981年   15篇
  1979年   15篇
  1978年   21篇
  1977年   18篇
  1976年   15篇
  1974年   18篇
  1973年   15篇
  1972年   14篇
排序方式: 共有10000条查询结果,搜索用时 280 毫秒
1.
2.
3.
Objective: Polyunsaturated fatty acids n-3 (PUFA n-3) have shown effects in reducing tumor growth, in particular eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) abundantly present in fish oil (FO). When these fatty acids are provided in the diet, they alter the functions of the cells, particularly in tumor and immune cells. However, the effects of α-linolenic fatty acid (ALA), which is the precursor of EPA and DHA, are controversial. Thus, our objective was to test the effect of this parental fatty acid. Methods: Non-tumor-bearing and tumor-bearing Wistar rats (70 days) were supplemented with 1 g/kg body weight of FO or Oro Inca® (OI) oil (rich in ALA). Immune cells function, proliferation, cytokine production, and subpopulation profile were evaluated. Results: We have shown that innate immune cells enhanced phagocytosis capacity, and increased processing and elimination of antigens. Moreover, there was a decrease in production of pro-inflammatory cytokines (tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6)) by macrophages. Lymphocytes showed decreased proliferation capacity, increased cluster of differentiation 8 (CD8+) subpopulation, and increased TNF-α production. Conclusions: Oil rich in ALA caused similar immune modulation in cancer when compared with FO.  相似文献   
4.
5.
Die Anaesthesiologie - Simulationstraining ist für die Notfallmedizin unverzichtbar, insbesondere in Hinsicht auf eine verbesserte Patientensicherheit. Methoden und Technologien umfassen ein...  相似文献   
6.
7.
Changes in resting energy expenditure (REE) of cancer patients vary depending on type of tumor, treatment time point and kind of treatment. Little is known about REE of acute leukemia adult patients after treatment, especially with results related to body weight or fat free mass (FFM). This study aimed to assess changes in REE of acute leukemia adult patients before and after the first remission induction. Evaluation of REE was performed by indirect calorimetry and predicted REE was calculated by Harris-Benedict equation. Weight and height were measured and compared to a control group of healthy individuals. FFM was assessed by bioelectrical impedance for adjusting REE values. We evaluated 18 patients and 26 healthy individuals. At diagnosis, patients presented REE, REE/weight, and REE/FFM higher than the controls. Reductions of REE, REE/weight, and REE/FFM were also observed in patients after the first cycle of chemotherapy. The predicted REE for the patients group showed significant lower value compared with measured REE. Before the first cycle of chemotherapy REE was increased but undergoes a reduction after treatment, reaching values similar to the controls. For predictive Harris-Benedict equation, stress factors should be added to avoid underestimation of REE before and after chemotherapy.  相似文献   
8.
9.
10.
INTRODUCTION: Transesophageal echocardiography (TEE) has become increasingly useful in the study of patients with suspected pulmonary thromboembolism. OBJECTIVE: The aim of this study was to prospectively evaluate the usefulness of TEE in the study of the distal part of the left pulmonary artery (LPA) as well as the influence of this procedure on total echocardiographic exam duration. METHODOLOGY: A prospective study in two groups of consecutive patients referred for TEE with a one- year interval between evaluation of Group A: 33 patients, 17 male, mean age 54 +/- 24 years, and Group B: 42 patients, 20 male, mean age 48 +/- 27 years (p = NS). The procedure was considered long when it took more than 3 min to evaluate the distal part of the LPA. RESULTS: In group A we were able to visualize the distal part of the LPA in 24 patients (73%) without significant prolongation of total exam duration in 16 patients (48% of group A). In one of the patients with suspected pulmonary thromboembolism thrombi were only observed in the distal part of the LPA. In group B we were able to visualize the distal part of the LPA in 36 patients (86%) without significant prolongation of total exam duration in 26 patients (61% of group B). CONCLUSIONS: 1. Visualization of the distal part of the LPA was possible in more patients, and with TEE time prolongation in less patients, in group B. These differences can be accounted for by the training of the operator in this technique. 2. The importance of visualization of this part of the LPA in guiding treatment in the subset of patients with pulmonary thromboembolism confirms the usefulness of this specific procedure.  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