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   1137423篇
  免费   80401篇
  国内免费   2905篇
耳鼻咽喉   15511篇
儿科学   39575篇
妇产科学   32119篇
基础医学   165010篇
口腔科学   31798篇
临床医学   100764篇
内科学   218305篇
皮肤病学   26925篇
神经病学   92189篇
特种医学   45844篇
外国民族医学   326篇
外科学   171665篇
综合类   24685篇
一般理论   412篇
预防医学   84603篇
眼科学   26671篇
药学   81722篇
  3篇
中国医学   2352篇
肿瘤学   60250篇
  2018年   12980篇
  2017年   10181篇
  2016年   12088篇
  2015年   13660篇
  2014年   17658篇
  2013年   26506篇
  2012年   36066篇
  2011年   37401篇
  2010年   22364篇
  2009年   20540篇
  2008年   35321篇
  2007年   37670篇
  2006年   38217篇
  2005年   37246篇
  2004年   36084篇
  2003年   34906篇
  2002年   33735篇
  2001年   51339篇
  2000年   52555篇
  1999年   44124篇
  1998年   12425篇
  1997年   11095篇
  1996年   10912篇
  1995年   10402篇
  1994年   9661篇
  1993年   9025篇
  1992年   34011篇
  1991年   33193篇
  1990年   32668篇
  1989年   31449篇
  1988年   28566篇
  1987年   28676篇
  1986年   26707篇
  1985年   25848篇
  1984年   19375篇
  1983年   16314篇
  1982年   9862篇
  1981年   8891篇
  1979年   17979篇
  1978年   13020篇
  1977年   11023篇
  1976年   10345篇
  1975年   11057篇
  1974年   13209篇
  1973年   12685篇
  1972年   11738篇
  1971年   10941篇
  1970年   10141篇
  1969年   9427篇
  1968年   8789篇
排序方式: 共有10000条查询结果,搜索用时 0 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.
An increase in chronic beryllium disease (CBD) has been suggested due to higher industrial use of beryllium alloys. Since occupational CBD is a perfect phenocopy of sarcoidosis, it might be misdiagnosed as sarcoidosis. In the current it was hypothesised that CBD exists in cohorts of sarcoidosis patients. In a prospective case study, sarcoidosis patients were evaluated for potential beryllium exposure. In those patients in whom beryllium exposure was confirmed and beryllium hypersensitivity demonstrated, the diagnosis of sarcoidosis was rejected and corrected to CBD. In 84 patients seen for re-evaluation or making a diagnosis of sarcoidosis, beryllium exposure was recognised and a diagnosis of CBD was made in 34 out of 84 patients. The time lag between clinical diagnosis of sarcoidosis and the final diagnosis of CBD ranged 0-18 yrs (median 3 yrs) and the mean (range) age at time of diagnosis of CBD was 43.9(25-80) yrs. Beryllium-contaminated workplaces causing disease encompassed a wide spectrum of industries and technical trades in which beryllium-exposure is generally not perceived as a health hazard. In conclusion, chronic beryllium disease still belongs to the spectrum of differential diagnoses of granulomatous disorders.  相似文献   
43.
44.
45.
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   
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.
Volume and profile of alcohol consumption among students and classmates as predictors of aggression and victimization: a multilevel analysis among Swiss adolescents

Objective:  

To test the effects of the volume of alcohol consumption and drinking patterns on alcohol-related aggression and victimization, both at the individual and class levels.  相似文献   
49.
50.
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   
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