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   2998658篇
  免费   218062篇
  国内免费   5120篇
耳鼻咽喉   41202篇
儿科学   98980篇
妇产科学   81674篇
基础医学   439234篇
口腔科学   83673篇
临床医学   272050篇
内科学   576973篇
皮肤病学   66657篇
神经病学   237421篇
特种医学   113090篇
外国民族医学   768篇
外科学   449562篇
综合类   64899篇
现状与发展   12篇
一般理论   1162篇
预防医学   236311篇
眼科学   70065篇
药学   221682篇
  13篇
中国医学   5876篇
肿瘤学   160536篇
  2019年   24041篇
  2018年   33359篇
  2017年   25305篇
  2016年   28473篇
  2015年   32034篇
  2014年   45129篇
  2013年   68220篇
  2012年   92950篇
  2011年   98925篇
  2010年   59004篇
  2009年   55645篇
  2008年   92883篇
  2007年   98860篇
  2006年   99836篇
  2005年   96773篇
  2004年   93010篇
  2003年   89519篇
  2002年   86682篇
  2001年   135708篇
  2000年   139284篇
  1999年   117225篇
  1998年   34121篇
  1997年   30143篇
  1996年   30361篇
  1995年   28871篇
  1994年   26646篇
  1993年   25102篇
  1992年   91661篇
  1991年   89600篇
  1990年   87617篇
  1989年   84402篇
  1988年   77465篇
  1987年   76473篇
  1986年   71608篇
  1985年   68865篇
  1984年   51457篇
  1983年   43702篇
  1982年   26146篇
  1979年   47464篇
  1978年   34054篇
  1977年   28447篇
  1976年   27248篇
  1975年   29050篇
  1974年   35045篇
  1973年   33391篇
  1972年   31194篇
  1971年   29521篇
  1970年   27202篇
  1969年   25846篇
  1968年   23771篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
The aim of the current study was to investigate whether alterations in N-terminal pro brain natriuretic peptide (NT-proBNP) reflect changes in right ventricular structure and function in pulmonary hypertension patients during treatment. The study consisted of 30 pulmonary hypertension patients; 15 newly diagnosed and 15 on long-term treatment. NT-proBNP, right heart catheterisation and cardiac magnetic resonance imaging measurements were performed, at baseline and follow-up. There were no significant differences between newly diagnosed patients and those on treatment at baseline or follow-up with respect to NT-proBNP, haemodynamics and right ventricular parameters. Relative changes in NT-proBNP during treatment were correlated to the relative changes in right ventricular end-diastolic volume index (r = 0.59), right ventricular mass index (r = 0.62) and right ventricular ejection fraction (r = -0.81). N-terminal pro brain natriuretic peptide measurements reflect changes in magnetic resonance imaging-measured right ventricular structure and function in pulmonary hypertension patients. An increase in N-terminal pro brain natriuretic peptide over time reflects right ventricular dilatation concomitant to hypertrophy and deterioration of systolic function.  相似文献   
93.
94.
95.
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   
96.
OBJECTIVE: To evaluate the prenatal distribution, associated conditions and outcome of the different types of right aortic arch (RAA) detected in fetal life. METHODS: This was a retrospective review of all cases of RAA detected prenatally between 1998 and 2005 in two tertiary referral centers. RESULTS: In the study period 71 cases of RAA were detected; 26 (37%) had RAA with aberrant left subclavian artery, 23 (32%) had RAA with mirror-image branching, 20 (28%) had RAA of unknown type and two (3%) had double aortic arch. While 20/26 cases with RAA and aberrant left subclavian artery were isolated findings, all 23 cases with RAA and mirror-image branching were associated with cardiac defects, namely tetralogy of Fallot (43%) or pulmonary atresia with ventricular septal defect (22%). Of the 20 cases with RAA, 19 of unknown type were associated with heterotaxy syndromes and had additional cardiac malformations and ambiguities of the situs. The two cases with DAA were isolated findings. Seven cases in our series (10%) had a microdeletion 22q11 and these were significantly associated with extracardiac malformations. The outcome in our series depended solely on the associated cardiac and extracardiac malformations, with the exception of one infant with isolated DAA, in whom a surgical correction was warranted. CONCLUSIONS: RAA detected in fetal life is associated frequently with other cardiac/non-cardiac malformations, heterotaxy syndromes and microdeletions 22q11. The associated conditions vary depending on the branching type of the brachiocephalic vessels and the presence of extracardiac malformations.  相似文献   
97.
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   
98.
99.
100.
AIMS: To report clinical outcomes of a large series of cases with advanced thyroid cancer. STUDY DESIGN: Three hundred and eighty-five patients at the UICC stages III and IV were selected for the study with thyroid cancer. RESULTS: Papillary carcinoma and sclerosing carcinoma have better survival than the Hürthle cell and insular types. Lymphatic metastasis does not appear to worsen the prognosis. All the tumour forms offer the chance of long survival. CONCLUSIONS: Surgical treatment is the primary treatment of thyroid carcinoma. The combined treatments of surgery, metabolic beam therapy, suppressive hormone therapy, radiotherapy and chemotherapy cure a high percentage of patients with the tumour at an advanced stage.  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