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   1141865篇
  免费   104165篇
  国内免费   4837篇
耳鼻咽喉   17814篇
儿科学   39619篇
妇产科学   30845篇
基础医学   148956篇
口腔科学   29213篇
临床医学   115460篇
内科学   238009篇
皮肤病学   30141篇
神经病学   93211篇
特种医学   44514篇
外国民族医学   306篇
外科学   188075篇
综合类   23990篇
现状与发展   72篇
一般理论   385篇
预防医学   84612篇
眼科学   25809篇
药学   73155篇
  3篇
中国医学   2050篇
肿瘤学   64628篇
  2021年   9659篇
  2020年   9895篇
  2019年   9277篇
  2018年   17376篇
  2017年   15066篇
  2016年   17213篇
  2015年   18398篇
  2014年   29027篇
  2013年   36643篇
  2012年   34232篇
  2011年   36106篇
  2010年   28236篇
  2009年   30830篇
  2008年   34320篇
  2007年   34363篇
  2006年   37154篇
  2005年   33346篇
  2004年   31916篇
  2003年   29840篇
  2002年   28957篇
  2001年   50637篇
  2000年   51005篇
  1999年   43413篇
  1998年   14629篇
  1997年   13339篇
  1996年   13275篇
  1995年   12755篇
  1994年   10889篇
  1993年   9954篇
  1992年   33573篇
  1991年   32804篇
  1990年   32053篇
  1989年   31024篇
  1988年   28204篇
  1987年   28179篇
  1986年   26324篇
  1985年   25343篇
  1984年   18942篇
  1983年   16037篇
  1982年   9781篇
  1979年   17218篇
  1978年   12570篇
  1977年   10720篇
  1976年   10008篇
  1975年   10475篇
  1974年   12563篇
  1973年   12103篇
  1972年   11213篇
  1971年   10360篇
  1970年   9649篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
41.
There is increasing evidence that the assessment of eosinophilic airway inflammation using induced sputum and measurement of airway hyperresponsiveness provides additional, clinically important information concerning asthma control. The aim of this study was to directly compare the effects of different treatments on these markers in patients with asthma and persistent symptoms, despite the use of low-dose inhaled corticosteroids. A double-blind four-way crossover study was performed, which compared a 1-month treatment with budesonide 400 mug b.i.d., additional formoterol, additional montelukast and placebo in 49 patients with uncontrolled asthma despite budesonide 100 mug b.i.d., with each treatment separated by a 4-week washout period. The change in sputum eosinophil count with formoterol (2.4 to 3.8% change, 0.6-fold reduction, 95% confidence interval (CI) 0.5-0.9) differed significantly from placebo (2.8 to 2.5% change, 1.1-fold reduction, 95% CI 0.7-1.6) and high-dose budesonide (2.7 to 1.6% change, 1.6-fold reduction, 95% CI 1.2-2.2). The effects of montelukast did not differ from placebo. The changes in methacholine airway responsiveness were small and did not differ between treatments. High-dose budesonide had the broadest range of beneficial effects on other outcomes, including symptom scores, morning peak expiratory flow and forced expiratory volume in one second. In conclusion, treatment given in addition to low-dose inhaled corticosteroids results in modest benefits. Formoterol and high-dose budesonide have contrasting effects on eosinophilic airway inflammation.  相似文献   
42.
43.
44.
Melioidosis is endemic in South East Asia, Asia and northern Australia. Infection usually follows percutaneous inoculation or inhalation of the causative bacterium, Burkholderia pseudomallei, which is present in soil and surface water in the endemic region. While 20-36% of melioidosis cases have no evident predisposing risk factor, the vast majority of fatal cases have an identified risk factor, the most important of which are diabetes, alcoholism and chronic renal disease. Half of all cases present with pneumonia, but there is great clinical diversity, from localised skin ulcers or abscesses without systemic illness to fulminant septic shock with multiple abscesses in the lungs, liver, spleen and kidneys. At least 10% of cases present with a chronic respiratory illness (sick > 2 months) mimicking tuberculosis and often with upper lobe infiltrates and/or cavities on chest radiography. As with tuberculosis, latency with reactivation decades after infection can also occur, although this is rare. Confirmation of diagnosis is by culture of B. pseudomallei from blood, sputum, throat swab or other samples. Microbiology laboratories need to be informed of the possibility of melioidosis, as those not familiar with it can misidentify the organism. Antibiotic therapy is initial intensive therapy with i.v. ceftazidime or meropenem or imipenem +/- cotrimoxazole for > or = 10 days, followed by eradication therapy with cotrimoxazole +/- doxycycline +/- chloramphenicol (first 4 weeks only) for > or = 3 months. Melioidosis has been increasingly recognised in returning travellers in Europe and recently melioidosis and colonisation with B. pseudomallei have been documented in cystic fibrosis patients visiting or resident in endemic areas.  相似文献   
45.
46.
Clinical decisions are often made with incomplete information, yet patient care decisions are made every day. Patients vary clinically, uncertainty exists in diagnostic and prognostic information, and many preventive and treatment alternatives have not been formally assessed for their effectiveness. Because scientific information will never answer all clinical questions, clinical decisions are partially based on probabilistic information.
This paper describes how to apply clinical decision making to diagnosing and managing dental caries and periodontal diseases. By using explicit information to quantify probabilities and outcomes, clinical decision making analyzes decisions made under uncertain conditions and the uncertain impact of clinical information.
Clinical decision making incorporates concepts for preventing, diagnosing and treating dental caries and periodontal diseases: risk assessment, evidence-based dentistry, and multiple oral health outcomes. This information can serve as a tool for clinicians to augment clinical judgment and expertise.  相似文献   
47.
48.
49.
Molecular characterization of Wuchereria bancrofti is essential to develop suitable anti-filarial drugs and vaccines. We describe here isolation, sequence analysis and cloning of a partial cDNA of an enzyme superoxide dismutase from this parasite. The immunoscreening of a lambda zap W. bancrofti microfilarial (Mf) cDNA library with microfilaremic sera had resulted in the isolation of several seroreactive clones including, WbSOD. This clone contained a 309 bp insert and showed significant nucleotide and deduced amino acid sequence homologies to the superoxide dismutases of other nematode parasites. The antioxidant property of this enzyme may have important contribution in the defense mechanism of the parasite against host immune response.  相似文献   
50.
Consecutive patients (n = 215) who were referred to optometric (55%) or multidisciplinary (45%) low-vision services and above 50 years of age were recruited from four hospitals in the Netherlands. They completed two vision-related quality of life questionnaires, the Vision Quality of Life Core Measure (VCM1) and the Low Vision Quality of Life Questionnaire (LVQOL), before their first visit with low-vision services and 1 year later. At follow-up, patients referred to multidisciplinary low-vision services had lower scores on the mobility subscale of the LVQOL than patients referred to optometric low-vision services [5.3 points; 95% confidence interval (CI): 0.2-10.5]. Paired sample t-tests for the two groups of patients taken together show improvement for the VCM1 (3.1 points; 95% CI: 0.6-5.6) and deterioration for the basic aspects of vision (3.5 points; 95% CI: 1.1-5.9) and the mobility (6.6 points; 95% CI: 3.7-9.5) subscales of the LVQOL. In conclusion, people referred to optometric services showed less deterioration in mobility than those referred to multidisciplinary services. No differences were observed for any of the other subscales of the LVQOL and the VCM1. Future research in this field should include randomized controlled designs comparing low-vision services with no treatment or placebo.  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