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   11691篇
  免费   569篇
  国内免费   56篇
耳鼻咽喉   88篇
儿科学   216篇
妇产科学   110篇
基础医学   1346篇
口腔科学   280篇
临床医学   765篇
内科学   3188篇
皮肤病学   167篇
神经病学   710篇
特种医学   321篇
外科学   2120篇
综合类   58篇
预防医学   324篇
眼科学   257篇
药学   983篇
中国医学   62篇
肿瘤学   1321篇
  2023年   45篇
  2022年   109篇
  2021年   212篇
  2020年   104篇
  2019年   151篇
  2018年   204篇
  2017年   147篇
  2016年   213篇
  2015年   206篇
  2014年   262篇
  2013年   392篇
  2012年   598篇
  2011年   598篇
  2010年   352篇
  2009年   314篇
  2008年   570篇
  2007年   646篇
  2006年   605篇
  2005年   619篇
  2004年   630篇
  2003年   579篇
  2002年   611篇
  2001年   455篇
  2000年   426篇
  1999年   385篇
  1998年   165篇
  1997年   146篇
  1996年   106篇
  1995年   103篇
  1994年   98篇
  1993年   91篇
  1992年   237篇
  1991年   205篇
  1990年   180篇
  1989年   183篇
  1988年   148篇
  1987年   165篇
  1986年   134篇
  1985年   139篇
  1984年   91篇
  1983年   84篇
  1982年   38篇
  1980年   36篇
  1979年   67篇
  1978年   41篇
  1975年   40篇
  1974年   36篇
  1972年   39篇
  1971年   46篇
  1969年   37篇
排序方式: 共有10000条查询结果,搜索用时 109 毫秒
1.
2.
Objectives: Phase angle (PA) is a poor prognostic factor in patients with advanced cancer. This study aimed to identify possible correlations between PA and symptoms, quality of life, fluid retention, and laboratory data in cancer patients in palliative care settings.

Methods: Individuals who visited the outpatient clinic or were admitted to the palliative care unit were eligible. Patients with a performance status of 4 and/or those unable to complete questionnaires were excluded. PA was evaluated using a bioanalyzer device. The correlation coefficient between PA and the variables of interest was analyzed.

Results: A total of 102 patients were analyzed. PA was weakly correlated with age (ρ = ?0.22), performance status (ρ = ?0.30), functional well-being (ρ?=?0.20), anorexia/cachexia subscale (ρ?=?0.22), and Functional Assessment of Anorexia/Cachexia Therapy trial outcome index (ρ?=?0.26). PA was also correlated with fluid retention (ρ = ?0.34) and albumin (ρ?=?0.32), C-reactive protein (ρ = ?0.31), and hemoglobin (ρ?=?0.41) levels. Sub-analysis stratified according to sex revealed that males demonstrated the same results; however, female sex demonstrated a correlation between PA and social well-being (ρ = ?0.43).

Conclusions: PA was correlated with physical condition, but not with psychological well-being.  相似文献   

3.
4.
Aliskiren is a novel orally active renin inhibitor for the treatment of hypertension. This study evaluated the antihypertensive efficacy, safety and tolerability of aliskiren in Japanese patients with hypertension. Forty hundred and fifty-five Japanese men and women with a mean sitting diastolic blood pressure of 95-110 mmHg were randomized to receive once-daily double-blind treatment for 8 weeks with aliskiren 75, 150 or 300 mg or placebo. Aliskiren produced significant, dose-dependent reductions in mean sitting diastolic blood pressure (p<0.0005 vs. placebo for each dose) and mean sitting systolic blood pressure (p<0.001 vs. placebo for each dose). The placebo-corrected reductions in mean sitting systolic/diastolic blood pressure were 5.7/4.0, 5.9/4.5 and 11.2/7.5 mmHg in the aliskiren 75, 150 and 300 mg groups, respectively. After 8 weeks' treatment, 27.8%, 47.8%, 48.2% and 63.7% of patients in the placebo and aliskiren 75, 150 and 300 mg groups, respectively, achieved a successful treatment response (diastolic blood pressure <90 mmHg and/or reduced by > or =10 mmHg from baseline; p<0.005 vs. placebo for each dose). Aliskiren treatment was well tolerated, with the incidence of adverse events reported in the active treatment groups (53-55%) being similar to that in the placebo group (50%). This study, which is the first to assess the antihypertensive efficacy and safety of aliskiren in Japanese patients with hypertension, demonstrates that the once-daily oral renin inhibitor aliskiren provides significant, dose-dependent reductions in blood pressure with placebo-like tolerability.  相似文献   
5.
Background: Ketamine potentiates intravenous or epidural morphine analgesia. The authors hypothesized that very-low-dose ketamine infusion reduces acute and long-term postthoracotomy pain.

Methods: Forty-nine patients scheduled to undergo open thoracotomy were randomly assigned to receive one of two anesthesia regimens: continuous epidural infusion of ropivacaine and morphine, along with intravenous infusion of ketamine (0.05 mg [middle dot] kg-1 [middle dot] h-1 [approximately 3 mg/h], ketamine group, n = 24) or placebo (saline, control group, n = 25). Epidural analgesia was continued for 2 days after surgery, and infusion of ketamine or placebo was continued for 3 days. Pain was assessed at 6, 12, 24, and 48 h after surgery. Patients were asked about their pain, abnormal sensation on the wound, and inconvenience in daily life at 7 days and 1, 3, and 6 months after surgery.

Results: The visual analog scale scores for pain at rest and on coughing 24 and 48 h after thoracotomy were lower in the ketamine group than in the control group (pain at rest, 9 +/- 11 vs. 25 +/- 20 and 9 +/- 11 vs. 18 +/- 13; pain on coughing, 26 +/- 16 vs. 50 +/- 17 and 30 +/- 18 vs. 43 +/- 18, mean +/- SD; P = 0.002 and P = 0.01, P < 0.0001 and P = 0.02, respectively). The numerical rating scale scores for baseline pain 1 and 3 months after thoracotomy were significantly lower in the ketamine group (0.5 [0-4] vs. 2 [0-5] and 0 [0-5] vs. 1.5 [0-6], median [range], respectively; P = 0.02). Three months after surgery, a higher number of control patients were taking pain medication (2 vs. 9; P = 0.03).  相似文献   

6.
BACKGROUND: Decreased plasma adiponectin is associated with impaired endothelial function and, thereby, increased risk for cardiovascular events. Glucocorticoid (GC) affects vascular endothelial cells either favourably or harmfully depending upon the dosages and duration. We examined the effect of GC pulse therapy on vascular endothelial function. METHODS: Fourteen young patients with IgA nephropathy were evaluated for flow-mediated vasodilation (FMD), plasma levels of adiponectin both in high molecular weight (HMW adiponectin) form and in single molecular form (total adiponectin), hepatocyte growth factor (HGF), asymmetric dimethylarginine (ADMA), and high-sensitive C-reactive protein, before and after a course of GC pulse therapy. RESULTS: GC pulse therapy significantly decreased FMD (from 7.2 +/- 2.6 to 5.7 +/- 2.5%, P < 0.01). Meanwhile, plasma adiponectin levels were significantly augmented (total adiponectin: from 10.2 +/- 4.0 to 12.1 +/- 6.3 microg/ml, P < 0.05; HMW: from 6.5 +/- 3.2 to 7.7 +/- 3.3 microg/ml, P < 0.05). In parallel, elevated concentrations of serum HGF (from 0.28 +/- 0.12 to 0.63 +/- 0.38 ng/ml, P < 0.01) and plasma ADMA (from 0.45 +/- 0.07 to 0.53 +/- 0.04 nmol/ml, P < 0.05) were observed. CONCLUSIONS: GC pulse therapy impaired endothelial function while increasing plasma adiponectin levels, which may in turn restore the endothelial function in patients with IgA nephropathy.  相似文献   
7.
We surgically treated a patient with biliary stricture and portal vein occlusion, after operation for gastric cancer with lymphadenectomy along the hepatoduodenal ligament, that had led to choledochal stone formation and a dilatated parabiliary venous system. A 57-year-old man without hepatic dysfunction exhibited hepatic duct dilatation with choledochal stone on ultrasonography and percutaneous transhepatic cholangiography, respectively. Pharmacoportography revealed occlusion of the portal vein and dilatation of the parabiliary venous system. Of various preoperative imaging studies used, enhanced computed tomography was most useful for delineating the surgical anatomy of the hepatoduodenal ligament. Complete preservation of the dilatated vessels, which functioned as the main portal collateral pathway, resulted in a successful choledocho-jejunostomy, with an uneventful postoperative course.  相似文献   
8.
Micro-shear bond strength of dual-cured resin cement to glass ceramics.   总被引:4,自引:0,他引:4  
OBJECTIVES: The aim of this study was to investigate the effects of sandblasting, etching, and a silane coupling agent on the ability of dual-cured resin cement to bond to glass ceramics designed for in indirect adhesive restoration. METHODS: A cast glass ceramic (Olympus Castable Ceramics) with a crystalline phase consisting of mica and beta-spondumene was selected as the substrate material. The glass surfaces, which were sandblasted, polished, or etched with phosphoric acid or hydrofluoric acid (HF), were bonded with a dual-cured resin cement (Panavia Fluoro Cement) using a dentin adhesive system (Clearfil SE Bond), both with and without a silane coupling agent. A micro-shear bond test was carried out to measure the bond strength of the resin cement to the glass surface. Each glass surface was bonded and tested using the shear test. In addition, surfaces with the bonding removed after the shear bond test, the adhesive interface between the glass and cement, and an etched glass surface without any bonding, were studied morphologically using scanning electron microscopy or field emission scanning electron microscopy. RESULTS: Usage of a silane coupling agent effectively raised the bond-strength values of resin cement (Fisher's PLSD, P<0.01). The effectiveness of using phosphoric acid etching to improve bonding was not clear (Fisher's PLSD, P>0.01). HF-etching for 30s seemed to over-etch the glass surface, resulting in adverse effects on bonding (Fisher's PLSD, P<0.01). SIGNIFICANCE: The micro-shear bond strength between Olympus Castable Ceramics and resin cement can be increased by the silane coupling agent used along with an acidic primer.  相似文献   
9.
10.
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