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   45145篇
  免费   2305篇
  国内免费   146篇
耳鼻咽喉   585篇
儿科学   1477篇
妇产科学   905篇
基础医学   5571篇
口腔科学   1064篇
临床医学   3144篇
内科学   11915篇
皮肤病学   1352篇
神经病学   3934篇
特种医学   1232篇
外科学   6843篇
综合类   206篇
现状与发展   1篇
一般理论   6篇
预防医学   3691篇
眼科学   833篇
药学   2323篇
中国医学   136篇
肿瘤学   2378篇
  2023年   294篇
  2022年   433篇
  2021年   1280篇
  2020年   556篇
  2019年   1251篇
  2018年   1747篇
  2017年   962篇
  2016年   937篇
  2015年   1037篇
  2014年   1302篇
  2013年   1964篇
  2012年   3284篇
  2011年   3360篇
  2010年   1860篇
  2009年   1554篇
  2008年   2828篇
  2007年   2929篇
  2006年   2797篇
  2005年   2798篇
  2004年   2474篇
  2003年   2256篇
  2002年   2214篇
  2001年   1130篇
  2000年   1308篇
  1999年   1007篇
  1998年   277篇
  1997年   210篇
  1996年   201篇
  1995年   171篇
  1994年   142篇
  1993年   124篇
  1992年   380篇
  1991年   298篇
  1990年   282篇
  1989年   206篇
  1988年   161篇
  1987年   156篇
  1986年   162篇
  1985年   137篇
  1984年   108篇
  1983年   72篇
  1982年   51篇
  1981年   54篇
  1979年   64篇
  1978年   49篇
  1976年   55篇
  1974年   71篇
  1973年   62篇
  1972年   54篇
  1969年   53篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Coronary angioplasty is known to mediate an inflammatory response. Recently, we have characterized the transient systemic inflammatory response after coronary stent implantation in patients with unstable angina by measuring different soluble protein markers. In the present study we have characterized the expression of various cellular activation markers in neutrophils, monocytes and lymphocytes from the same group of patients. Peripheral blood samples were taken before and 24 h, 48 h and 7 days after successful coronary stenting in 58 patients. Cell surface markers (CD11b/CD18 and CD38) were analyzed by flow cytometry to determine the activation of neutrophils, monocytes and T lymphocytes. We found that coronary angioplasty with stent implantation produces an increase in the cell surface expression of CD11b/CD18 in neutrophils and CD38 in monocytes, following a similar time-course with a peak after 24 h, returning to basal levels after 48 h and a second peak after 7 days. However, T lymphocytes were not found to be activated. These results suggest that coronary stent implantation induces a different pattern inducing soluble and cellular inflammation markers, and therefore, they should be taken into account in patients undergoing stent implantation to study clinical correlations.  相似文献   
62.
63.
Vitamin A (retinol), a fat-soluble vitamin, is an essential nutrient for the normal functioning of the visual system, epithelial cell integrity and growth, immunity, and reproduction. Our group has investigated the effect of high doses of oral vitamin A on early childhood diarrhea in our prospective community-based studies from Northeast Brazil and found a beneficial role in reducing the mean duration but not incidence of diarrheal episodes. In this study, we explored the role of retinol supplementation in intestinal cell lines following Clostridium difficile toxin A (TxA) challenge. C. difficile is the most common anaerobic pathogen borne with antibiotic-borne diarrhea and pseudomembranous colitis. Since retinol is critical for the integrity of tight junctions and to modulate the cell cycle, we have focused on changes in transepithelial electrical resistance (TEER) in Caco-2, a more differentiated intestinal cell line, and on models of cell proliferation, migration and viability in IEC-6 cells, an undifferentiated crypt cell line, following TxA injury. In this model, retinol therapy reduced apoptosis, improved cell migration and proliferation, and prevented the reduction in TEER, following C. difficile TxA challenge in a glutamine-free medium. These results suggest the role of retinol in protecting intestinal epithelial barrier function from C. difficile TxA enterotoxic damage.  相似文献   
64.

Objective  

The aim of the project was to assess the effectiveness and safety of weekly epoetin-beta (EB) in patients with gastrointestinal cancer (GIC) subjected to concomitant chemoradiotherapy (CCTRT).  相似文献   
65.
AIMS: The aims of our study were to determine if insulin resistance is associated with increased plasma levels of non-esterified fatty acids (NEFA), glycerol, 3-hydroxybutyrate and triglycerides in obese children. We also studied whether the presence of acanthosis nigricans (AN) led to further alterations in the above parameters. METHODS: A total of 101 children were studied on their first visit to the paediatric endocrine clinic. Seventy-four were obese, 30 of them with AN. The remaining 27 were non-obese healthy children (control group). NEFAs, glycerol, triglycerides, 3-hydroxybutyrate, insulin, leptin, adiponectin and glucose were determined in blood samples obtained after overnight fasting. The insulin resistance index (IRI) was calculated following the homeostasis model assessment (HOMA). Data from the three groups were compared using appropriate statistical tests. RESULTS: No differences in age, sex ratio and pubertal stage were observed among the three groups. The group of children with the highest body mass index (BMI) showed higher plasma levels of insulin and leptin, higher IRI and lower plasma levels of adiponectin. As insulin and IRI increased, NEFA and 3-hydroxybutyrate decreased and triglycerides increased. When obese children were categorized by BMI, the presence of AN further exacerbated these differences. CONCLUSIONS: In obese children, insulin resistance is associated with plasma lipid alterations suggestive of both decreased adipose tissue lipolysis and hepatic beta-oxidation and increased hepatic synthesis of triglycerides. Such a metabolic condition may facilitate fat storage and hinder weight loss.  相似文献   
66.
67.
68.
69.
70.
This study aimed to determine whether a weight-adjusted dose of subcutaneous enoxaparin is as effective and safe as oral acenocoumarol for the secondary prophylaxis of pulmonary embolism. Three hundred and eighty consecutive noncancer outpatients hospitalized with an episode of symptomatic pulmonary embolism selected treatment with acenocoumarol or enoxaparin at a dose of 1 mg/kg once daily after being informed of the type of administration and expected frequency of laboratory monitoring for both medicinal products. Endpoints were symptomatic recurrent thromboembolic events evaluated by standard objective testing, and a composite endpoint of recurrent venous thromboembolism, major bleeding, and death from any cause. One hundred and ninety-nine patients (52%) chose acenocoumarol therapy and 181 chose enoxaparin monotherapy. Four patients in the enoxaparin group (2.2%) and six patients in the acenocoumarol group (3%) had an objective thromboembolic recurrence (hazard ratio, 1.35; 95% confidence interval, 0.38-4.79; P = 0.64). Nine patients in the enoxaparin group (5.0%) had a hemorrhagic complication compared with 11 in the acenocoumarol group (5.5%) (P = 0.81). The hospital length of stay was shorter with enoxaparin compared with acenocoumarol (11 versus 16 days, P = 0.0001). Enoxaparin is as effective and safe as acenocoumarol in the secondary prevention of recurrent thromboembolic disease and is associated with shorter hospitalization.  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