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   6822篇
  免费   458篇
  国内免费   51篇
耳鼻咽喉   68篇
儿科学   121篇
妇产科学   107篇
基础医学   875篇
口腔科学   55篇
临床医学   750篇
内科学   1836篇
皮肤病学   94篇
神经病学   685篇
特种医学   243篇
外科学   942篇
综合类   49篇
现状与发展   1篇
一般理论   1篇
预防医学   380篇
眼科学   103篇
药学   440篇
中国医学   2篇
肿瘤学   579篇
  2023年   38篇
  2022年   55篇
  2021年   144篇
  2020年   98篇
  2019年   142篇
  2018年   187篇
  2017年   124篇
  2016年   138篇
  2015年   174篇
  2014年   226篇
  2013年   317篇
  2012年   538篇
  2011年   519篇
  2010年   316篇
  2009年   299篇
  2008年   459篇
  2007年   504篇
  2006年   417篇
  2005年   463篇
  2004年   473篇
  2003年   396篇
  2002年   370篇
  2001年   65篇
  2000年   57篇
  1999年   51篇
  1998年   84篇
  1997年   69篇
  1996年   55篇
  1995年   60篇
  1994年   52篇
  1993年   39篇
  1992年   43篇
  1991年   34篇
  1990年   20篇
  1989年   26篇
  1988年   18篇
  1987年   21篇
  1986年   18篇
  1985年   19篇
  1984年   15篇
  1983年   15篇
  1982年   10篇
  1980年   15篇
  1978年   12篇
  1977年   14篇
  1974年   13篇
  1973年   12篇
  1972年   9篇
  1971年   14篇
  1967年   8篇
排序方式: 共有7331条查询结果,搜索用时 15 毫秒
991.
992.
993.
OBJECTIVES: We performed a meta-analysis of randomized trials that enrolled ST-segment elevation myocardial infarction patients treated with fibrinolysis to assess the potential benefits of: 1) rescue percutaneous coronary intervention (PCI) versus no PCI; 2) systematic and early (< or =24 h) PCI versus delayed or ischemia-guided PCI; 3) fibrinolysis-facilitated PCI versus primary PCI alone. BACKGROUND: The impact of PCI strategies after fibrinolysis on mortality or reinfarction remains to be established. METHODS: The meta-analysis was performed using the odds ratio (OR) as the parameter of efficacy with a random effect model. Fifteen randomized trials (5,253 patients) were selected. The primary end point was mortality or the combined end point of death or reinfarction. RESULTS: Rescue PCI for failed fibrinolysis reduced mortality (6.9% vs. 10.7%) (OR, 0.63; 95% confidence interval [CI], 0.39 to 0.99; p = 0.055) and the rate of death or reinfarction (10.8% vs. 16.8%) (OR, 0.60; 95% CI, 0.41 to 0.89; p = 0.012) compared with a conservative approach. Systematic and early PCI performed during the "stent era" led to a nonsignificant reduction in mortality compared with delayed or ischemia-guided PCI (3.8% vs. 6.7%) (OR, 0.56; 95% CI, 0.29 to 1.05; p = 0.07) and to a 2-fold reduction in the rate of death or reinfarction (7.5% vs. 13.2%) (OR, 0.53; 95% CI, 0.33 to 0.83; p = 0.0067). This benefit contrasted with a nonsignificant increase in the rate of both mortality (5.5% vs. 3.9%, p = 0.33) or death or reinfarction (9.6% vs. 5.7%, p = 0.06) observed in the "balloon era." Fibrinolysis-facilitated PCI was associated with more reinfarction as compared with primary PCI alone (5.0% vs. 3.0%) (OR, 1.68; 95% CI, 1.12 to 2.51; p = 0.013) without significant impact on mortality (OR, 1.30; 95% CI, 0.92 to 1.83; p = 0.13). CONCLUSIONS: Our findings support rescue PCI and systematic and early PCI after fibrinolysis. However, the current data do not support fibrinolysis-facilitated PCI in lieu of primary PCI alone.  相似文献   
994.
106 consecutive patients with Alzheimer's disease living in the community were examined in a memory clinic from a neurological department. They were screened for weight loss over the last 2 years. Age, duration of the disease, behavioral disorders, mini mental status examination, body mass index were recorded. Tumor necrosis factor alpha (TNFalpha), interleukin-1beta (IL-1beta), interleukin 6 (IL-6) and interleukin 2 (IL-2) blood levels were measured. Weight loss was reported in 42.5% of the patients. TNFalpha levels were significantly higher in these patients (18.8 versus 15.8 pg/mL; p=0.04) than in patients without weight loss. Weight loss was also associated with a lower MMSE score (16.9 versus 19.3; p=0.03), current pacing (20% versus 1.6%; p=0.002), and hallucinations (20.0% versus 3.3%; p=0.008). The levels of the other cytokines did not differ between the patients with and without weight loss. Our findings suggest an association between high levels of circulating TNFalpha and unexplained weight loss in Alzheimer's disease.  相似文献   
995.
The catastrophic variant is an accelerated form of the antiphospholipid syndrome resulting in multiorgan failure because of multiple small vessel occlusions. We report a case of catastrophic antiphospholipid syndrome in a patient with subacute cutaneous lupus erythematosus and ischemic bowel, who presented with acute abdominal pain due to diffuse right colon and small bowel necrosis requiring large resection, associated with acute respiratory distress syndrome, thrombocytopenia and disseminated intravascular coagulation. Histopathological examination of resected tissues showed diffuse arteriolar and venous thrombosis but no vasculitis, and mesenteric artery lumen severely narrowed by intimal fibrosis. The patient died 15 days after admission despite treatment with anticoagulation, steroids, continuous hemofiltration and plasma exchange. Ischemic bowel and diffuse intestinal necrosis may be secondary to the antiphospholipid syndrome, and a high level of suspicion and an early diagnosis are required.  相似文献   
996.
The most common repair technique for P2 prolapse is quadrangular resection of the posterior leaflet associated with a plication of the mitral annulus or with a sliding plasty. Although effective, these techniques do not respect the anatomy of the mitral valve, especially the physiological role of the posterior leaflet. Herein is described another technique which does not include P2 removal, thus preserving the posterior leaflet mobility. This technique represents a new approach to mitral valve repair that respects the motion of the two leaflets, allowing a more physiological opening of the mitral valve.  相似文献   
997.
998.
BACKGROUND: Relations of mediators of inflammation and hemostasis with preclinical atherosclerosis have been poorly analyzed. The aim of this study was to test potential associations of these blood markers with indicators of cardiovascular risk and atherosclerotic burden in asymptomatic, nonsmoking, hypercholesterolemic men. METHODS: A total of 87 men underwent cardiovascular risk assessment by means of 10-year Framingham risk calculation (median 9%) and atherosclerotic burden evaluation by means of ultrasonographic measurement of common carotid intima-media thickness and assessment of atherosclerotic plaques at three arterial sites (three-site plaques). RESULTS: Of the markers C-reactive protein, tumor necrosis factor-alpha, interleukin-10, factor VIIc, fibrinogen, plasminogen activator inhibitor-activator, soluble intercellular adhesion molecule-1, soluble P-selectin (sP-selectin), and von Willebrand factor, only sP-selectin was positively and independently associated with high Framingham risk score (>9%) (71.7 +/- 3.6 ng/mL, n = 33 v 59.6 +/- 2.8, n = 54; mean +/- SEM; P < .05) and with three-site plaques (75.4 +/- 5.7 ng/mL, n = 14 v 62.0 +/- 2.5, n = 73; P < .05). After adjustment for all of the above markers and for cardiovascular risk factors, odd ratios of having high Framingham risk and three-site plaques were 3.38 (1.43 to 10.21) and 5.23 (1.74 to 23.52) respectively, per 1-standard deviation increase in sP-selectin. CONCLUSIONS: These results confirm that among several hemostasis and inflammation mediators, only sP-selectin blood level was associated with preclinical atherosclerosis. It might confer to sP-selectin measurement a clinical usefulness for detecting and managing high cardiovascular risk in primary prevention.  相似文献   
999.
Is High Job Strain Associated With Hypertension Genesis?   总被引:2,自引:0,他引:2  
BACKGROUND: The aim of this analysis was to test, in a large sample of normotensive subjects, the short-term influence of job strain on the onset of hypertension. METHODS: According to the questionnaire of Karasek et al, job strain was divided into four modalities: (high strain, low strain, passive, and active) based on job demand (eg, the need to work hard and quickly) and job latitude (eg, control over skill use, time allocation, and organizational decisions) scores. High strain (HS) was defined by a high demand and a low job decision latitude. Individual data obtained in 926 (age 41 +/- 6 years) healthy normotensive or newly diagnosed hypertensive subjects were analyzed. Subjects participated in two prospective work site surveys designed to assess the influence of job strain on hypertension development. Relationships between job strain modalities and work site blood pressure (BP) levels were assessed using a general linear model. A complementary analysis using the the Pearson Phi coefficient (Z analysis) was implemented to explore nonlinear or scattered relationships between job strain and onset of hypertension. RESULTS: Systolic BP (SBP) was linearly related significantly to BMI and alcohol consumption, whereas diastolic BP (DBP) was related to age. The linear model did not find any relationship between SBP or DBP and job strain modalities. Using the Z analysis, development of systolic hypertension (SBP >140 mm Hg) was significantly associated with high job strain (P < .001). CONCLUSIONS: Our results suggest that there is no global relationship between job strain and BP levels. However our methodology revealed a significant association between job strain and work site BP in a predominantly male subgroup of newly diagnosed hypertensive subjects exposed to high job strain.  相似文献   
1000.
OBJECTIVES: The aim of this retrospective study was to assess the long term results of long-lasting endoscopic stenting for benign biliary strictures related to laparoscopic cholecystectomy. Additional biological and morphological data were collected from these patients during follow-up. METHODS: Patients undergoing ERCP for post-laparoscopic cholecystectomy biliary stricture in one of the three participating centers between 1990 and December 2001 were identified. Only patients with successful endoscopic stenting were subsequently included and analyzed. Follow-up data were obtained from referring centers, general practitioners and patients or relatives. Hepatic blood tests and abdominal ultrasound were proposed to all the patients who had not undergone further treatments after stent removal. RESULTS: Eight-eight patients had undergone ERCP for benign biliary stricture related to laparoscopic cholecystectomy. Stenting failed in 19 patients. Balloon dilatation alone was used in four patients. Strictures were successfully stented in 65 patients. The mean number of stents inserted at the same time was 1.6. The mean duration of stenting was 14 months (range 1-120 months). Eighteen patients (28%) developed biliary or pancreatic symptoms during stenting. ERCP was considered satisfactory at the end of stenting (i.e. no remaining stricture or minor remaining change on ERCP) in 45 patients (69%). Twenty-two patients were lost to follow-up. Twenty-nine out of forty-three patients (67%) remained symptom-free with normal updated blood tests and abdominal ultrasound during a mean follow-up of 28 months (range 12-117 months) after stent removal. None of the patients with a normal ERCP at the end of stenting developed stricture recurrence during follow-up. Eleven patients were operated (8 with persistence of stricture, 2 for stricture recurrence up to 63 months after stent removal, 1 for pancreatitis). CONCLUSION: Based on clinical, morphological and biological criteria, a long-term success was obtained in 70% of patients with post-laparoscopic cholecystectomy benign biliary strictures, after several months of endoscopic stenting.  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