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   850篇
  免费   16篇
  国内免费   9篇
耳鼻咽喉   1篇
儿科学   28篇
妇产科学   11篇
基础医学   37篇
口腔科学   4篇
临床医学   228篇
内科学   227篇
皮肤病学   28篇
神经病学   49篇
特种医学   2篇
外科学   77篇
综合类   17篇
一般理论   1篇
预防医学   105篇
药学   40篇
肿瘤学   20篇
  2016年   3篇
  2015年   32篇
  2014年   30篇
  2013年   22篇
  2012年   42篇
  2011年   49篇
  2010年   28篇
  2009年   47篇
  2008年   30篇
  2007年   43篇
  2006年   61篇
  2005年   30篇
  2004年   23篇
  2003年   6篇
  2002年   13篇
  2001年   33篇
  2000年   20篇
  1999年   35篇
  1998年   42篇
  1997年   21篇
  1996年   29篇
  1995年   29篇
  1994年   28篇
  1993年   17篇
  1992年   11篇
  1991年   11篇
  1990年   9篇
  1989年   7篇
  1988年   9篇
  1987年   11篇
  1986年   7篇
  1985年   6篇
  1984年   4篇
  1983年   9篇
  1982年   5篇
  1981年   3篇
  1980年   3篇
  1978年   5篇
  1977年   3篇
  1976年   4篇
  1970年   3篇
  1968年   2篇
  1964年   3篇
  1963年   3篇
  1961年   2篇
  1960年   2篇
  1959年   4篇
  1958年   2篇
  1947年   3篇
  1941年   3篇
排序方式: 共有875条查询结果,搜索用时 15 毫秒
71.
Background: Post‐operative cognitive dysfunction (POCD) is detected by administration of a neuropsychological test battery. Reaction time testing is at present not included as a standard test. Choice reaction time (CRT) data from the first International Study of Post‐operative Cognitive Dysfunction study were collected, but the association between POCD and reaction time has not been presented before. We hypothesized that CRT could be used as a screening tool for POCD. Methods: Patients aged 60 years or older scheduled for major surgery with general anaesthesia were recruited from 13 centres in nine countries. CRT was measured 52 times using the four boxes test. Patients performed the test before surgery (n=1083), at 1 week (n=926) and at 3 months (n=852) post‐operatively. CRT for the individual patient was determined as the median time of correct responses. The usefulness of the CRT as a screening tool for POCD was determined by the receiver–operator characteristic (ROC) curve. Results: Patients with POCD 1 week after surgery had a significantly longer reaction time compared with patients without POCD: 857 (221) vs. 762 (201) ms, respectively (P<0.0001). Also at 3 months, patients with POCD had a significantly longer CRT. ROC curves revealed that a reaction time of 813 ms was the most appropriate cut‐off at 1 week and 762 ms at 3 months but the positive predictive value for POCD was low: 34.4% and 14.7%, respectively. Conclusions: Post‐operative cognitive dysfunction is associated with impaired performance in the CRT test but the test is a poor predictor of POCD.  相似文献   
72.
Summary. We assessed the reliability and construct validity of the Compatible MRI scale for evaluation of elbows, and compared the diagnostic performance of MRI and radiographs for assessment of these joints. Twenty‐nine MR examinations of elbows from 27 boys with haemophilia A and B [age range, 5–17 years (mean, 11.5)] were independently read by four blinded radiologists on two occasions. Three centres participated in the study: (Toronto, n = 24 examinations; Atlanta, n = 3; Cuiaba, n = 2). The number of previous joint bleeds and severity of haemophilia were reference standard measures. The inter‐reader reliability of MRI scores was substantial (ICC = 0.73) for the additive (A)‐scale and excellent (ICC = 0.83) for the progressive (P)‐scale. The intrareader reliability was excellent for both P‐scores (ICC = 0.91) and A‐scores (ICC = 0.93). The total P‐ and A‐scores correlated poorly (r = 0.36) or moderately (r = 0.54), but positively, with clinical‐laboratory measurements. The total MRI scores demonstrated high accuracy for discrimination of presence or absence of arthropathy [P‐scale, area‐under‐the‐curve (AUC) = 0.94 ± 0.05; A‐scale, AUC = 0.89 ± 0.06], as did the soft tissue scores of both scales (P‐scale, AUC = 0.90 ± 0.06; A‐scale, AUC = 0.86 ± 0.06). Areas‐under‐the‐curve used to discriminate severe disease demonstrated high accuracy for both P‐MRI scores (AUC = 0.83 ± 0.09) and A‐MRI scores (AUC = 0.87 ± 0.09), but non‐diagnostic ability to discriminate mild disease. Similar results were noted for radiographic scales. In conclusion, both MRI scales demonstrated substantial to excellent reliability and accuracy for discrimination of presence/absence of arthropathy, and severe/non‐severe disease, but poor to moderate convergent validity for total scores and non‐diagnostic discriminant validity for mild/non‐mild disease. Compared with radiographic scores, MRI scales did not perform better for discrimination of severity of arthropathy.  相似文献   
73.
74.
75.
76.
The efficacy and viral safety of a pasteurized, immunoaffinity-purified procoagulant factor VIII protein (FVIII:C; Monoclate-P) was studied in two multicentre, prospective, open-label trials in 30 previously untreated patients, 18 with severe (< 1% FVIII:C activity), and 12 with moderate (1% to 5% FVIII:C activity) haemophilia A. Clinical assessments, performed at screening and regularly thereafter for 6 to > 24 months (maximum 34 months), showed that none of 24 assessable patients acquired illnesses consistent with monitored transfusion-transmissible diseases. No patients acquired hepatitis B surface antigen, or antibodies against hepatitis B core antigen, hepatitis C, or human immunodeficiency virus. Likewise, no patients acquired treatment-related hepatitis A antibodies or sustained elevations of alanine aminotransferase levels. The safety profile for Monoclate-P is brought about by a multi-step safety system that incorporates viral inactivation (through a combination of immunoaffinity chromatography and pasteurization) plus donor screening, plasma testing, and quality assurance. The inhibitor development rate (13% low titre, 10% high titre) was similar to that reported in the literature for other FVIII concentrates (24% to 52%). The most frequently reported adverse events were related to typical infant and childhood diseases. Monoclate-P was effective in all patients treated according to protocol, except in two, who developed inhibitors.  相似文献   
77.
78.
BACKGROUND: Tissue factor (TF) and its specific inhibitor, tissue factor pathway inhibitor (TFPI), are important contributors to the initiation of the coagulation process. OBJECTIVES: To compare plasma levels of soluble TF (sTF) and free-TFPI (f-TFPI) between patients with stable angina pectoris (SAP) and acute coronary syndrome (ACS) and to assess the impact of the two variables on long-term prognosis. PATIENTS/METHODS: Patients with SAPs (n = 1146) and acute coronary syndrome (n = 523) from the AtheroGene study were included and followed for 2.3 years. Because of the strong impact of unfractionated heparin (UFH) on f-TFPI levels, but not on sTF levels, patients having received UFH before blood drawing were excluded from the analyses on f-TFPI (n = 226). RESULTS: On admission, no significant differences in sTF levels were observed between SAP and ACS patients. By comparison to patients with stable angina, f-TFPI levels significantly increased in patients with acute unstable angina and further increased in patients presenting with non-ST-elevation myocardial infarction and ST-elevation myocardial infarction (P < 10(-4)). Among the 1669 individuals with a coronary artery disease, 56 died from a cardiovascular cause. In prospective analyses, high sTF levels were independently associated with an increased risk of cardiovascular death in individuals with ACS (fully adjusted hazard ratio associated with one quartile increase = 2.06; 95% confidence interval 1.24-3.45; P = 0.006) but not in those with SAP (hazard ratio = 1.07; 95% confidence interval 0.78-1.46; P = 0.67). In SAP and ACS patients, high f-TFPI levels were not independently associated with an increased risk of cardiovascular death. CONCLUSIONS: Plasma sTF levels were predictive of cardiovascular mortality in individuals with ACS, whereas f-TFPI levels were associated with the severity of myocardial damage on admission but were not independently related to outcome.  相似文献   
79.
在聚乙氧基辛基苯基醚存在下氯米帕明的电分析特性张正奇,陈展光,陈声宗,曾鸽鸣,杨植岗(湖南大学化学化工系,长沙410082)氯米帕明(clomipramine,CMI)能选择性地抑制中枢神经系统内5-HT的重吸收,可消除抑郁心境,恢复活力。本品使用安...  相似文献   
80.
目的探讨全麻下下胸段硬膜外阻滞对单肺通气期间肺内分流(Qs/Qt)的影响。方法术中需行单肺通气的30例择期开胸手术患者,ASAⅡ~Ⅲ,随机分为全麻组(GA组,n=15),全麻复合下胸段硬膜外组(GE组,n=15)。两组病人分别于麻醉前、双肺通气30min、单肺通气5、15、30min时采动脉血及混合静脉血,行血气分析,并计算出Qs/Qt等。结果两组患者在单肺通气后5、15、30min,Qs/Qt均增加(P<0.01),动脉氧分压(PaO2)较双肺通气时下降(P<0.01)。但在各时间点两组Qs/Qt以及PaO2无显著性差异。结论下胸段硬膜外阻滞对单肺通气期间肺内分流和动脉氧合无明显影响,可安全用于开胸单肺通气患者的麻醉。  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