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   15474篇
  免费   904篇
  国内免费   146篇
耳鼻咽喉   97篇
儿科学   329篇
妇产科学   232篇
基础医学   1751篇
口腔科学   460篇
临床医学   1328篇
内科学   4863篇
皮肤病学   182篇
神经病学   1494篇
特种医学   603篇
外科学   2186篇
综合类   28篇
预防医学   583篇
眼科学   135篇
药学   680篇
中国医学   9篇
肿瘤学   1564篇
  2023年   127篇
  2022年   221篇
  2021年   418篇
  2020年   291篇
  2019年   351篇
  2018年   419篇
  2017年   337篇
  2016年   412篇
  2015年   434篇
  2014年   604篇
  2013年   808篇
  2012年   1171篇
  2011年   1231篇
  2010年   678篇
  2009年   705篇
  2008年   1085篇
  2007年   1142篇
  2006年   1053篇
  2005年   1016篇
  2004年   1003篇
  2003年   825篇
  2002年   747篇
  2001年   117篇
  2000年   88篇
  1999年   114篇
  1998年   127篇
  1997年   126篇
  1996年   92篇
  1995年   85篇
  1994年   66篇
  1993年   77篇
  1992年   58篇
  1991年   61篇
  1990年   51篇
  1989年   32篇
  1988年   36篇
  1987年   38篇
  1986年   42篇
  1985年   31篇
  1984年   34篇
  1983年   30篇
  1982年   20篇
  1981年   16篇
  1980年   14篇
  1978年   9篇
  1977年   8篇
  1972年   7篇
  1968年   7篇
  1967年   10篇
  1966年   8篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
OBJECTIVES: (1) To compare two stool antigen EIAs (HpSA, FemtoLab) and PCR of ureaseA and cagA in feces, with (13)C-urea breath test (UBT). (2) To ascertain whether a simplified UBT (breath collection time = 10 min) is as reliable as the standard assay (30 min). DESIGN AND METHODS: Helicobacter pylori status was recorded in Group 1 (n = 187) by UBT, H. pylori stool antigen, ureA and cagA PCR in feces. UBT with 10, 20 and 30 min sampling was performed in Group 2 patients (n = 283). RESULTS: The sensitivity and specificity of HpSA, FemtoLab, and ureA were 67% and 99%, 90% and 96%, 35% and 98%, respectively. cagA results were positive in 16/48 H. pylori-positive, and in 5/100 H. pylori-negative patients. The results of UBT with a 10- and 30-min sampling strictly overlapped. CONCLUSION: UBT with 10 min breath collection and FemtoLab stool antigen assay are the most reliable non-invasive tests to diagnose H. pylori infection.  相似文献   
992.
993.
BACKGROUND: Coronary care units (CCUs) currently treat a variety of diseases, but little is known about the effectiveness of CCUs on heart conditions other than acute myocardial infarction. OBJECTIVES: The objectives of this study were to evaluate the association between direct admission to CCUs and the risk of inhospital death in patients with heart disease, to investigate factors affecting direct admission to a CCU, and to assess the effect of CCU admission on the use of invasive procedures in patients with arrhythmias. RESEARCH DESIGN: We conducted a retrospective analysis of discharge-abstract data from Lazio, Italy, hospitals. We used logistic regression, propensity score, and instrumental variable analysis to compare inhospital risk of death between patients admitted to CCUs and to ordinary wards in 13 different groups of heart disease. We used linear regression to study the association between the rate of CCU admission and the relative risk of death. RESULTS: The study included 181,049 heart disease admissions, of which 8620 were admitted to CCUs (4.8%). Risk of death was significantly lower in patients admitted directly to CCUs for "acute myocardial infarction" (odds ratio [OR], 0.57), "acute ischemic heart disease" (OR, 0.55), and "other arrhythmias" (OR, 0.56). Mortality ORs were inversely related to the rate of CCU admission. CCU patients with arrhythmias received more invasive procedures (OR, 2.70) than non-CCU patients. CONCLUSION: Direct admission to a CCU is associated with a decrease in mortality for patients with "acute myocardial infarction," "acute heart ischemia," and "other arrhythmias." Patients most likely to benefit from CCU care are preferentially admitted to CCUs. CCUs make larger use of invasive procedures than ordinary wards.  相似文献   
994.
A 13-year-old male patient, who underwent Mustard operation for a very complex congenital heart disease (CHD), after palliation presented a decrease of the sinus node function, developing a tachy-brady syndrome and a mild dysfunction of atrioventricular (AV) conduction. He was successfully treated using a DDDRP pacemaker, which ensured a suitable atrial rhythm and was able to interrupt supraventricular tachycardia episodes. Until now, hospitalization related to episodes of heart failure or symptomatic arrhythmia, has not been necessary.  相似文献   
995.
OBJECTIVE: The PROspective pioglitAzone Clinical Trial In macroVascular Events (PROactive) assesses the effect of pioglitazone, a peroxisome proliferator-activated receptor agonist, with anti-inflammatory and vascular properties, on the secondary prevention of macrovascular events in type 2 diabetes. RESEARCH DESIGN AND METHODS: PROactive is an on-going randomized, double-blind outcome study in patients with type 2 diabetes managed with diet and/or oral blood glucose-lowering drugs (combination of oral agents with insulin is permitted) who have a history of macrovascular disease. Patients are randomized to receive pioglitazone (forced titration from 15 to 30 to 45 mg, depending on tolerability) or placebo in addition to existing therapy. The primary end point is the time from randomization to occurrence of a new macrovascular event or death. Follow-up is estimated to span 4 years. RESULTS: A total of 5238 patients have been randomized from 19 countries. At entry into the study, patients enrolled are a mean age of 61.8 years, with type 2 diabetes for a mean of 9.5 years; 60.9 and 61.5% are taking metformin or a sulfonylurea, respectively; and 33.6% are using insulin in addition to oral glucose-lowering drugs. The majority of patients are men (66.1%). Patients are required to meet one or more of entry criteria, as follows: >6 months' history of myocardial infarction (46.7%); coronary artery revascularization (30.8%), stroke (18.8%), or acute coronary syndrome for >3 months (13.7%); other evidence of coronary artery disease (48.1%); or peripheral arterial occlusive disease (19.9%). One-half (48.5%) of the patients have two or more of these risk factors. Three-quarters (75.4%) have hypertension, and 58.8% are current or previous smokers. CONCLUSIONS: The cohort of patients enrolled in PROactive is a typical type 2 diabetic population at high risk of further macrovascular events. The characteristics of this population are ideal for assessing the ability of pioglitazone to reduce the cardiovascular risk of patients with type 2 diabetes.  相似文献   
996.
OBJECTIVE: To investigate weight loss expectations (expected 1-year BMI loss, dream BMI, and maximum acceptable BMI) in obese patients seeking treatment and to examine whether expectations differ by sex, weight, diet and weight history, age, psychological factors, and primary motivations for weight loss. RESEARCH METHODS AND PROCEDURES: 1891 obese patients seeking treatment in 25 Italian medical centers (1473 women; age, 44.7 +/- 11.0 years; BMI, 38.2 +/- 6.5 kg/m2) were evaluated. Diet and weight history, weight loss expectations, and primary motivation for seeking treatment (health or improving appearance) were systematically recorded. Psychiatric distress, binge eating, and body image dissatisfaction were tested by self-administered questionnaires (Symptom CheckList-90, Binge Eating Scale, and Body Uneasiness Test). RESULTS: In 1011 cases (53.4%), 1-year expected BMI loss was > or = 9 kg/m2, dream BMI was 26.0 +/- 3.4 kg/m2 (corresponding to a 32% loss), and maximum acceptable BMI was 29.3 +/- 4.4 kg/m2 (-23%). BMI and age were the strongest predictors of weight goals. Weight loss necessary to reach the desired targets was largely in excess of weight loss observed during previous dieting. Psychiatric distress, body dissatisfaction, and binge eating did not predict weight loss expectations. The primary motivation for weight loss was concern for future or present health; women seeking treatment to improve appearance had a lower grade of obesity, were younger, and had first attempted weight loss at a younger age. DISCUSSION: Obese Italian patients had unrealistic weight loss expectations. There were significant disparities between patients' perceptions and physicians' weight loss recommendations of desirable treatment outcome.  相似文献   
997.
998.
999.
1000.
Context  The metabolic syndrome has been identified as a target for dietary therapies to reduce risk of cardiovascular disease; however, the role of diet in the etiology of the metabolic syndrome is poorly understood. Objective  To assess the effect of a Mediterranean-style diet on endothelial function and vascular inflammatory markers in patients with the metabolic syndrome. Design, Setting, and Patients  Randomized, single-blind trial conducted from June 2001 to January 2004 at a university hospital in Italy among 180 patients (99 men and 81 women) with the metabolic syndrome, as defined by the Adult Treatment Panel III. Interventions  Patients in the intervention group (n = 90) were instructed to follow a Mediterranean-style diet and received detailed advice about how to increase daily consumption of whole grains, fruits, vegetables, nuts, and olive oil; patients in the control group (n = 90) followed a prudent diet (carbohydrates, 50%-60%; proteins, 15%-20%; total fat, <30%). Main Outcome Measures  Nutrient intake; endothelial function score as a measure of blood pressure and platelet aggregation response to L-arginine; lipid and glucose parameters; insulin sensitivity; and circulating levels of high-sensitivity C-reactive protein (hs-CRP) and interleukins 6 (IL-6), 7 (IL-7), and 18 (IL-18). Results  After 2 years, patients following the Mediterranean-style diet consumed more foods rich in monounsaturated fat, polyunsaturated fat, and fiber and had a lower ratio of omega-6 to omega-3 fatty acids. Total fruit, vegetable, and nuts intake (274 g/d), whole grain intake (103 g/d), and olive oil consumption (8 g/d) were also significantly higher in the intervention group (P<.001). The level of physical activity increased in both groups by approximately 60%, without difference between groups (P = .22). Mean (SD) body weight decreased more in patients in the intervention group (–4.0 [1.1] kg) than in those in the control group (–1.2 [0.6] kg) (P<.001). Compared with patients consuming the control diet, patients consuming the intervention diet had significantly reduced serum concentrations of hs-CRP (P = .01), IL-6 (P = .04), IL-7 (P = 0.4), and IL-18 (P = 0.3), as well as decreased insulin resistance (P<.001). Endothelial function score improved in the intervention group (mean [SD] change, +1.9 [0.6]; P<.001) but remained stable in the control group (+0.2 [0.2]; P = .33). At 2 years of follow-up, 40 patients in the intervention group still had features of the metabolic syndrome, compared with 78 patients in the control group (P<.001). Conclusion  A Mediterranean-style diet might be effective in reducing the prevalence of the metabolic syndrome and its associated cardiovascular risk.   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