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   20215篇
  免费   1763篇
  国内免费   52篇
耳鼻咽喉   218篇
儿科学   590篇
妇产科学   473篇
基础医学   2486篇
口腔科学   472篇
临床医学   2369篇
内科学   3549篇
皮肤病学   232篇
神经病学   1963篇
特种医学   733篇
外科学   2543篇
综合类   601篇
一般理论   24篇
预防医学   2146篇
眼科学   473篇
药学   1533篇
中国医学   15篇
肿瘤学   1610篇
  2022年   131篇
  2021年   259篇
  2020年   180篇
  2019年   255篇
  2018年   335篇
  2017年   254篇
  2016年   303篇
  2015年   331篇
  2014年   437篇
  2013年   668篇
  2012年   987篇
  2011年   960篇
  2010年   547篇
  2009年   501篇
  2008年   899篇
  2007年   963篇
  2006年   882篇
  2005年   868篇
  2004年   864篇
  2003年   795篇
  2002年   811篇
  2001年   630篇
  2000年   582篇
  1999年   525篇
  1998年   296篇
  1997年   239篇
  1996年   258篇
  1995年   239篇
  1994年   206篇
  1993年   211篇
  1992年   412篇
  1991年   403篇
  1990年   430篇
  1989年   398篇
  1988年   392篇
  1987年   397篇
  1986年   368篇
  1985年   316篇
  1984年   247篇
  1983年   207篇
  1982年   149篇
  1981年   140篇
  1980年   127篇
  1979年   243篇
  1978年   163篇
  1977年   142篇
  1976年   143篇
  1975年   153篇
  1974年   165篇
  1973年   132篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
Peripheral arterial thromboembolism and thrombosis of arterial grafts continue to threaten viability of extremities. Percutaneous intra-arterial thrombolysis (IAT) and angiodilatation have afforded limb salvage in some of these patients. Proper patient selection appears to be the hallmark of success with IAT. During a recent three-year period, we used IAT in 32 extremities in 28 patients who had acute arterial insufficiency. Before IAT, 16 extremities were painful at rest, and 16 had incapacitating claudication. The overall success rate was 38%, but some degree of thrombolysis occurred in 88%. Limb salvage was achieved in 27 of 32 extremities (84%). Only five of 17 limbs (29%) with arterial graft thrombosis required no operation or an operation of lesser magnitude than predicted before IAT. Of six extremities with native arterial embolism, four (67%) were completely cleared with IAT. Major complications occurred in eight cases (25%), with two IAT-related deaths (6%). This study suggests that IAT is best reserved for individuals with acute limb ischemia caused by arterial embolus, those whose degree of ischemia would tolerate a 24-hour trial of IAT, and those whose femoral or tibial runoff is not likely to require remedial operation.  相似文献   
12.
OBJECTIVE: To investigate whether orofacial tardive dyskinesia (OTD) is associated with frontal lobe dysfunction and whether either are related to the coping abilities independent of psychiatric symptoms in older people with psychotic disorders. METHODS: A total of 52 patients, aged over 65 years or over, who satisfied International Classification of Diseases, Tenth Revision criteria for psychotic disorders (F20-F29) were recruited into the study. OTD was measured using the Abnormal Involuntary Movements Scale and Waddington et al.'s (1993) criteria. Neuropsychological measures were specifically selected to assess different aspects of frontal function and coping was measured using a semistructured interview. Psychiatric symptoms were assessed using the Positive and Negative Syndrome Scale (PANSS). RESULTS: Patients with OTD showed more severe global cognitive impairment compared to patients without OTD. Group differences on measures of frontal lobe dysfunction were not maintained following adjustment for global cognitive impairment. Patients with OTD did not differ from patients without OTD on coping measures. Scores on the general psychopathology subscale of the PANSS, which includes symptoms associated with depression and anxiety, consistently predicted patients' negative perceptions of stressors and appraisals of coping, but cognitive impairment did not predict coping independent of symptoms. CONCLUSION: The association between coping and general psychopathology in older patients with psychosis warrants further investigation as both variables may be amenable to psychological interventions.  相似文献   
13.
14.
BACKGROUND: Cardiac rehabilitation (CR) has an evidence base but traditional models may not readily apply to people living in rural and remote regions. AIM:: To outline published comprehensive and non-hospital based CR models used for people discharged from hospital after a cardiac event that have potential relevance to those living in rural and remote areas in Australia. METHODS: The PubMed database was searched using Medical subject headings (MeSH) terms and the key word 'cardiac rehabilitation' limited to clinical trials. Articles were retrieved if they included at least two components of CR and were not based in an outpatient setting. RESULTS: No CR models specifically developed for rural and remote areas were identified. However, 14 studies were found that outlined 11 non-conventional comprehensive CR models. All provided CR in a home-based setting. Health professionals provided support via telephone contact or home visits, and via resources such as the Heart Manual. Reported outcomes from these CR programs varied: ranging from an increase in knowledge of risk factors, to improvements in physical activity, decreased risk factor profile, improved psychological and social functioning and reductions in health service costs and mortality. CONCLUSION: Home-based, CR models have the most substantive evidence base and, therefore the greatest potential to be developed and made accessible to eligible people living in rural and remote areas.  相似文献   
15.
Lymphocytes from 10 paired colostrum and peripheral blood specimens were examined to determine if the colostral T cell population differs from the peripheral blood T cell population in subset distribution. The percentages of lymphocytes staining with OKT3, OKT4, and OKT8 murine monoclonal antibody were determined. Lymphocytes from colostrum were 74.7 +/- 2.5% OKT3+, 50.6 +/- 2.3% OKT4+, 24.0 +/- 1.7% OKT8+, whereas peripheral blood lymphocytes were 78.7 +/- 1.9% OKT3+, 48.4 +/- 1.4% OKT4+, and 29.8 +/- 1.6% OKT8+. The percentage of colostrum lymphocytes positive for OKT3 was significantly although not strikingly lower than the OKT3 percentage for blood lymphocytes (p less than 0.05). This difference was due to the lower percentage of OKT8 positive lymphocytes in colostrum compared with blood (p less than 0.01). Although the T cell subset distribution of colostrum generally appears to be similar to that in the peripheral blood, there were small differences in OKT3 and OKT8 percentages that were statistically significant suggesting the possibility of some selectivity of the colostral T cell population.  相似文献   
16.
Dyssynchronous ventricular contraction in severe heart failurecontributes to low cardiac output, worsening symptoms, and poorprognosis. Recognition of the effect of dyssynchrony in heartfailure, and the possibility of manipulating the sequence ofelectrical cardiac activation to improve the efficiency of mechanicalevents, led Cazeau et al. to attempt four-chamber pacing in1994.1 This early system could stimulate both atria and bothventricles extrinsically, and could dictate the temporal relationshipbetween atrial systole and ventricular systole, and the ventriculo-ventricularrelationship. Modern cardiac resynchronization therapy (CRT),involving pacing of the right and left ventricles, with rightatrial pacing to optimize atrio-ventricular delay, has evolvedrapidly from this beginning. Left bundle branch block (LBBB) on the surface electrocardiogram(ECG) has been considered a marker of mechanical dyssynchronyas it represents a delay in conduction of depolarization tothe left ventricle, with the greatest delay usually being in  相似文献   
17.
PURPOSE: Epidermal growth factor receptor is expressed in pediatric malignant solid tumors. We conducted a phase I trial of gefitinib, an epidermal growth factor receptor tyrosine kinase inhibitor, in children with refractory solid tumors. PATIENTS AND METHODS: Gefitinib (150, 300, 400, or 500 mg/m2) was administered orally to cohorts of three to six patients once daily continuously until disease progression or significant toxicity. Pharmacokinetic studies were performed during course one (day 1 through 28). RESULTS: Of the 25 enrolled patients, 19 (median age, 15 years) were fully evaluable for toxicity and received 54 courses. Dose-limiting toxicity was rash in two patients treated with 500 mg/m2 and elevated ALT and AST in one patient treated with 400 mg/m2. The maximum-tolerated dose was 400 mg/m2/d. The most frequent non-dose-limiting toxicities were grade 1 or 2 dry skin, anemia, diarrhea, nausea, and vomiting. One patient with Ewing's sarcoma had a partial response. Disease stabilized for 8 to > or = 60 weeks in two patients with Wilms' tumor and two with brainstem glioma (one exophytic). At 400 mg/m2, the median peak gefitinib plasma concentration was 2.2 microg/mL (range, 1.2 to 3.6 microg/mL) and occurred at a median of 2.3 hours (range, 2.0 to 8.3 hours) after drug administration. The median apparent clearance and median half-life were 14.8 L/h/m2 (range, 3.8 to 24.8 L/h/m2) and 11.7 hours (range, 5.6 to 22.8 hours), respectively. Gefitinib systemic exposures were comparable with those associated with antitumor activity in adults. CONCLUSION: Oral gefitinib is well tolerated in children. Development of the drug in combination with cytotoxic chemotherapy will be pursued.  相似文献   
18.
19.
Exercise advice is a well established component of the conservative management of intermittent claudication. Supervised programmes of exercise remain relatively uncommon and are provided mainly in secondary care. This review outlines the evidence for the effectiveness of different exercise regimens and the relative benefits of exercise therapy, where comparisons have been made with medical therapy, angioplasty and surgery.  相似文献   
20.
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