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   6338篇
  免费   451篇
  国内免费   135篇
耳鼻咽喉   41篇
儿科学   134篇
妇产科学   216篇
基础医学   781篇
口腔科学   159篇
临床医学   650篇
内科学   1214篇
皮肤病学   95篇
神经病学   411篇
特种医学   277篇
外科学   833篇
综合类   454篇
现状与发展   1篇
一般理论   2篇
预防医学   382篇
眼科学   141篇
药学   513篇
  4篇
中国医学   133篇
肿瘤学   483篇
  2023年   65篇
  2022年   141篇
  2021年   223篇
  2020年   127篇
  2019年   155篇
  2018年   227篇
  2017年   143篇
  2016年   148篇
  2015年   224篇
  2014年   274篇
  2013年   340篇
  2012年   516篇
  2011年   519篇
  2010年   297篇
  2009年   284篇
  2008年   367篇
  2007年   376篇
  2006年   361篇
  2005年   303篇
  2004年   263篇
  2003年   256篇
  2002年   227篇
  2001年   128篇
  2000年   152篇
  1999年   100篇
  1998年   38篇
  1997年   30篇
  1996年   24篇
  1995年   34篇
  1994年   24篇
  1993年   19篇
  1992年   64篇
  1991年   45篇
  1990年   32篇
  1989年   35篇
  1988年   36篇
  1987年   28篇
  1986年   28篇
  1985年   36篇
  1984年   32篇
  1983年   25篇
  1982年   22篇
  1981年   26篇
  1980年   13篇
  1979年   18篇
  1978年   13篇
  1977年   16篇
  1976年   14篇
  1975年   11篇
  1974年   10篇
排序方式: 共有6924条查询结果,搜索用时 15 毫秒
1.
Thoracic empyema in uremic patients on maintenance hemodialysis is a challenging situation. The clinical characteristics are rarely reported, and the surgical outcomes remain unclear. We report our experience with video-assisted thoracoscopic surgery in these patients during 10-year period of time. Between 2005 and 2015, we retrospectively reviewed the clinical characteristics, bacteriological studies, and thoracoscopic surgical results of 23 empyema patients undergoing maintenance hemodialysis. The mean patient age was 67.1 ± 12.9 years. All patients had additional preexisting systemic diseases. The mean duration of hemodialysis was 34.7 ± 25.8 months. The infections causing empyema were pneumonia in 11 (47.8%), blood stream infection in 8 (34.8%), and uremic pleuritis in 4 (17.4%). Among the 22 identified microorganisms, the most common pathogen was methicillin-resistant Staphylococcus aureus (31.8%). After thoracoscopic surgery, 8 patients (34.8%) required additional procedures for complications, including 2 patients who required repeated thoracoscopy for hemothorax and 6 (26.1%) patients who required open drainage for residual empyema. The mean hospital stay was 62.4 days, and 6 patients (26.1%) died in the hospital. Univariate and multivariate analyses revealed that maintenance hemodialysis longer than 5 years was a significant factor associated with in-hospital mortality (odds ratio: 14.8, 95% confidence interval 1.5–151.6; p < 0.0001). While surgical management of thoracic empyema in uremic patients undergoing maintenance hemodialysis is associated with high rates of complication and mortality, thoracoscopic surgery is feasible, especially for patients undergoing hemodialysis for less than 5 years.  相似文献   
2.
3.
目的分析一腓骨肌萎缩症家系的临床表现及不同基因检测方法的特点。方法收集一CMT家系8名成员临床资料,并应用等位基因特异性PCR-双酶切方法及多重连接依赖的探针扩增技术(MLPA)检测PMP22基因突变情况,同时选择60名性别、年龄无明显差异的健康人做为对照组。结果该家系中患病者以行走不稳、跨阈步态,伴有弓形足为主要临床表现。该家系中5名成员经等位基因特异性PCR-双酶切及MLPA方法均检测出PMP22基因重复序列,其中出现临床症状的有4名(Ⅱ3、Ⅱ9、Ⅱ11、Ⅲ7),未出现临床症状但基因检测结果示PMP22基因重复序列的为携带者有1名(Ⅲ5),家系中余3名成员及对照组60名均未见重复序列。结论基因检测在明确CMT诊断中起重要作用,且MLPA法筛查基因时操作更简便、灵敏度更高、特异性更好。  相似文献   
4.
Detection of cell apoptosis by MTT assay.]   总被引:1,自引:0,他引:1  
OBJECTIVE: To study the feasibility of using MTT assay to detect cell apoptosis. METHODS: K562 cells were grown in RPMI 1640 medium supplemented with 10% calf serum and 4 micromol/L arsenic trioxide. Apoptosis was induced in the cultured cells by As2O3, and the cells were detected with optical microscope, DNA gel electrophoresis and MTT staining respectively. RESULT: MTT staining could also accurately detect cell apoptosis, by which the apoptotic cells were easily distinguished from normal cells and dead cells. CONCLUSION: MTT staining is simple, convenient and practical for detecting cell apoptosis.  相似文献   
5.
Purpose  There has been increasing interest in the occupational health of workers in small enterprises, especially in developing countries. This study examines the association between psychosocial job characteristics and fatigue, and attempts to identify risk factors for fatigue among workers of small enterprises in southern Taiwan. Methods  A structured questionnaire was administered to workers receiving regular health examinations between August 2005 and January 2006. The questionnaire collected demographic information and data on working conditions, personal health status and life styles. It also collected information on psychosocial job characteristics, fatigue and psychological distress using three instruments. Results  A total of 647 workers with mean age of 43.7 were completed. Probable fatigue was found in 34.6% of the sample. Fatigue was found by multiple logistic regressions to be associated with the lack of exercise, working in shifts, depression score and lack of social support at workplace. Conclusions  This study found associations between life style, psychosocial job characteristics and fatigue. Because the high prevalence of probable fatigue was found in such small enterprises, the authors suggest that a short interview with some quick questionnaires in health checkup for these small enterprise workers are helpful to early detect psychosocial and fatigue problems.  相似文献   
6.
7.
The performances of three widely different cathode materials (Pt, strontium-doped lanthanum manganite (LSM), and NiO) have been compared for use with proton conducting Li2SO4–Al2O3 composite electrolyte, using H2S–air and H2–air fuel cells operating at 600 °C. Surface analysis and electrochemical techniques were used to characterize fresh and used electrode materials. Pt or LSM cathodes each became covered with Li2SO4 and Al2O3 and, as a consequence, the fuel cells showed poor performance. In contrast, the NiO cathode catalyst did not become covered with Li2SO4 and good fuel cell performance was achieved. Exceptionally good current densities of over 100 mA/cm2 and power densities of over 30 mW/cm2 were obtained for H2S–air fuel cells having Mo–Ni–S anode catalysts. Slight agglomeration of NiO particles during fuel cell operation had only a minor effect on performance.  相似文献   
8.
γ射线照射对血小板活化的影响   总被引:4,自引:0,他引:4  
目的:探讨γ射线照射对单采血小板保存过程中血小板活化的影响.方法:用细胞分离机单采血小板20人份,以27Gyy射线照射,标准条件下保存5天,间隔取样分别用RIA,ELISA方法检测血小板表面P-选择素(P-Selectin)、血浆中可溶性P-选择素(sP-Selectin)及β-血小板球蛋白(β-TG)含量.结果:在保存3d,5d后,照射组及对照组中血小板表面P-Selectin含量、血浆中sP-Selectin及β-TG含量与保存前比较差异显著(P<0.05),但是两组间比较无统计学差异(P>0.05),结论:γ射线照射不会促进血小板的活化.  相似文献   
9.
10.
OBJECTIVE: The aim of this study was to examine the dental condition and oral manifestations in diabetic and nondiabetic uremic patients undergoing hemodialysis. STUDY DESIGN: A total of 128 patients undergoing hemodialysis therapy were classified into the diabetic and nondiabetic groups and examined for uremic oral manifestations, dental caries, and the periodontal status. All the patients received predialytic salivary pH examination. In the diabetic group, the correlation between oral findings and glycemic controlled levels, which was collected based on Hb A1C values, were further studied. RESULTS: The diabetic group exhibited significantly higher prevalence of caries and more severe dry mouth, taste change, and mucosa pain than the nondiabetic group. The diabetic group tended to have lower predialytic salivary pH, and patients with poor glycemic control (ie, Hb A1C > 9%) showed higher incidence of dry mouth, mucosal pain, and tongue coating. However, the DMFT and CPI index were not associated with glycemic control in the diabetic group. CONCLUSIONS: This study reveals that diabetic uremic patients undergoing maintained hemodialysis exhibited a potentially higher risk for dental decay and xerostomia. Lower salivary pH and poor glycemic control may affect oral manifestations. Further research is needed to clarify the combined influence of diabetic nephropathy on oral health.  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