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   4039篇
  免费   156篇
  国内免费   32篇
耳鼻咽喉   12篇
儿科学   88篇
妇产科学   66篇
基础医学   491篇
口腔科学   87篇
临床医学   254篇
内科学   1086篇
皮肤病学   73篇
神经病学   279篇
特种医学   134篇
外科学   740篇
综合类   20篇
一般理论   1篇
预防医学   100篇
眼科学   53篇
药学   286篇
中国医学   3篇
肿瘤学   454篇
  2023年   19篇
  2022年   36篇
  2021年   78篇
  2020年   37篇
  2019年   50篇
  2018年   73篇
  2017年   54篇
  2016年   59篇
  2015年   83篇
  2014年   111篇
  2013年   132篇
  2012年   202篇
  2011年   184篇
  2010年   140篇
  2009年   132篇
  2008年   222篇
  2007年   237篇
  2006年   268篇
  2005年   267篇
  2004年   252篇
  2003年   274篇
  2002年   259篇
  2001年   34篇
  2000年   25篇
  1999年   53篇
  1998年   94篇
  1997年   90篇
  1996年   90篇
  1995年   66篇
  1994年   70篇
  1993年   46篇
  1992年   37篇
  1991年   39篇
  1990年   30篇
  1989年   20篇
  1988年   15篇
  1987年   16篇
  1986年   21篇
  1985年   12篇
  1984年   11篇
  1983年   17篇
  1981年   15篇
  1980年   12篇
  1978年   12篇
  1975年   8篇
  1958年   19篇
  1957年   30篇
  1956年   35篇
  1955年   37篇
  1954年   28篇
排序方式: 共有4227条查询结果,搜索用时 0 毫秒
71.
We aimed to determine the economic impact of absenteeism and presenteeism from five conditions potentially comorbid with depressive symptoms—back or neck disorders, depression, anxiety, or emotional disorders, chronic headaches, stomach or bowel disorders, and insomnia—among Japanese workers aged 18–59 yr. Participants from 19 workplaces anonymously completed Stanford Presenteeism Scale questionnaires. Participants identified one primary health condition and determined the resultant performance loss (0–100%) over the previous 4-wk period. We estimated the wage loss by gender, using 10-yr age bands. A total of 6,777 participants undertook the study. Of these, we extracted the data for those in the 18–59 yr age band who chose targeted primary health conditions (males, 2,535; females 2,465). The primary health condition identified was back or neck disorders. We found that wage loss due to presenteeism and absenteeism per 100 workers across all 10-yr age bands was high for back or neck disorders. Wage loss per person was relatively high among those identifying depression, anxiety, or emotional disorders. These findings offer insight into developing strategies for workplace interventions on increasing work performance.  相似文献   
72.
In order to investigate the underlying mechanism of alterations in bone mineral metabolism in patients with type 2 diabetes, we determined circulating levels of bone functional markers along with urinary excretion of sorbitol (SOR) and bone mineral density (BMD), and also examined their mutual interrelationship. A total of 151 male type 2 diabetic patients were examined in this study. Forty-eight age-matched male healthy subjects were also studied as the controls. A significant reduction of serum intact osteocalcin (i-OC) was found in the diabetic groups (p<0.01). On the other hand, circulating levels of tartrate resistant acid phosphatase (TRAP) in the diabetic patients were significantly higher than those in the controls (p<0.01). Interestingly, a significantly negative relationship was observed between BMD and serum TRAP (p<0.01), although no significant relationship was noted between BMD and serum i-OC in diabetic patients. Urinary excretion of SOR was significantly elevated in the diabetic patients when compared with the controls (p<0.01). In addition, a significantly positive correlation was observed between serum TRAP and urinary SOR (p<0.01), but not between serum i-OC and urinary SOR. Elevated serum TRAP in diabetes was reduced after the administration of aldose reductase inhibitor (p<0.05). It seems most likely that the increase in osteoclastic function probably due to accelerated polyol pathway plays a crucial role in the pathogenesis of decreased bone mineral content in male patients with type 2 diabetes.  相似文献   
73.
Two-staged pancreatoduodenectomy, including exteriorization of the pancreatic juice and second-look pancreaticojejunostomy, has been recommended for high-risk patients to avoid pancreatic leakage, which often causes intra-abdominal hemorrhage. We present a new technique of interventional pancreaticojejunostomy under both fluoroscopy and endoscopy without second-look laparotomy. A 77-year-old woman with local recurrence and liver metastasis from colon cancer underwent hepato-pancreatoduodenectomy with the external drainage of pancreatic juice via the pancreatic duct tube without pancreaticojejunostomy. Two months later, the jejunum was punctured with the insertion of a 5-F needle-knife into the pancreatic fistula during endoscopic observation of jejunal lumen, followed by the insertion of two 0.35-inch guidewires into the jejunum and the pancreatic fistula. Finally, a 10-Fr stenting tube was placed between the jejunum and the pancreatic fistula. No complications developed.  相似文献   
74.
75.
76.
OBJECTIVE: Inflammation has been suggested as a risk factor for the development of atherosclerosis, while some components of metabolic syndrome X have been related to inflammatory markers. We hypothesized that adipocyte secreting protein, adiponectin and leptin, for which have been demonstrated an association with metabolic syndrome X and coronary artery disease, may be associated with inflammatory markers in nondiabetic humans. DESIGN AND METHODS: We measured high-sensitivity C-reactive protein (hs-CRP), as an inflammatory marker, and adiponectin and leptin concentrations in 384 nondiabetic Japanese women (mean+/-s.e.m. age 53.6+/-0.8 Years, body mass index (BMI) 23.0+/-0.2 kg/m(2)) undergoing measurement of markers of metabolic syndrome X. RESULTS: The women who had a low-grade hs-CRP elevation (>2.0 mg/l) were significantly older and had higher BMI, body fat mass (BFM), total cholesterol (TC), triglyceride (TG), atherogenic index (AI=(TC-HDLC)/HDLC), where HDLC is high-density lipoproten-cholesterol), fasting blood glucose and leptin concentrations before and after adjustment for BMI or BFM, while lower HDLC and adiponectin concentrations before and after adjustment compared with women with normal CRP levels (<0.5 mg/l). BMI, BFM, TG, AI and leptin before and after adjustment were found to be correlated with hs-CRP levels, while HDLC and adiponectin before and after adjustment were inversely correlated (all P<0.0001). hs-CRP was independently associated with white blood cell count, blood urea nitrogen and AI and inversely with adiponectin/BFM in the stepwise regression analysis model. CONCLUSIONS: These data demonstrate a significant decrease in plasma adiponectin in low-grade chronic inflammation, and suggest that there is an important linkage between inflammation/adipose tIssue/atherosclerosis.  相似文献   
77.
A sensitive sandwich enzyme-linked immunosorbent assay (ELISA) has been established to estimate serum thrombopoietin (TPO) concentrations in healthy volunteers and patients with haemopoietic disorders. The ELISA uses a mouse monoclonal antibody (Ab) as the capture Ab and a biotinylated rabbit polyclonal Ab as the detector. The ELISA was reproducible, highly sensitive and specific for human TPO. The coefficients of intra- and inter-assay variation were from 3.0% to 4.9% and from 5.9% to 6.1%, respectively. The quantitative limit of the ELISA was 0.09 fmol/ml in serum. The quantitative limit was lower than the normal level. The dose–response curves of serum samples from healthy volunteers and patients with haemopoietic disorders were parallel to the standard curves. The ELISA did not cross-react with a variety of blood components and cytokines to produce false-positive results.
The serum TPO concentrations from 29 normal males and 21 females were 0.79 ± 0.35 and 0.70 ± 0.26 fmol/ml, respectively. Serum TPO levels in patients with aplastic anaemia (AA), acute lymphocytic leukaemia (ALL) and essential thrombocythaemia (ET) were measured using the ELISA. The serum TPO levels in the patients with ET ( n  = 6, 2.80 ± 1.55 fmol/ml) were higher than the normal level. The patients with AA ( n  = 7, 18.53 ± 12.37 fmol/ml) and ALL ( n  = 5, 10.36 ± 5.57 fmol/ml) had significantly higher serum TPO levels than normal individuals. These results indicate that the ELISA specific to TPO should prove useful in measuring the TPO concentration in serum samples.  相似文献   
78.
Soluble Fas ligand and atherosclerosis in hypertensive patients   总被引:2,自引:0,他引:2  
BACKGROUND : The Fas-Fas ligand (FasL) system is involved in apoptosis in many types of cells. Recently, the expression of FasL on endothelial cells was reported. FasL is cleaved by a metalloproteinase and released in serum as soluble FasL (sFasL). Vasoactive substances, including metalloproteinase, are modulated by endothelial dysfunction. Advanced atherosclerosis and impaired endothelial function are seen in hypertensive patients. The inflammatory response has an important role in the development of atherosclerosis, whereas C-reactive protein (CRP) is associated with the presence and severity of atherosclerosis. OBJECTIVE : To measure the intima-media thickness of the common carotid artery and evaluate the relationship between atherosclerosis and serum sFasL concentrations in hypertensive patients. PATIENTS AND MAIN OUTCOME MEASURES : Forty-seven patients with hypertension participated in the study. The intima-media thickness of the common carotid artery was evaluated by ultrasound imaging. Serum concentrations of sFasL were measured by enzyme-linked immunosorbent assay. RESULTS : Intima-media thickness correlated positively with age (r = 0.362, P = 0.012) and sFasL concentrations (r =0.332, P = 0.022), and negatively with creatinine clearance (r = -0.399, P = 0.0055). A general linear model analysis with atherosclerotic risk factors and sFasL revealed that age, sFasL, high-density lipoprotein-cholesterol and systolic blood pressure were significantly associated with intima-media thickness. Furthermore, we demonstrated that serum sFasL is directly associated with CRP concentration (r = 0.316, P = 0.030). CONCLUSIONS : These results indicated that serum sFasL concentration is associated with atherosclerosis and inflammatory disease, in patients with hypertension.  相似文献   
79.
80.
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