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   797篇
  免费   55篇
  国内免费   6篇
耳鼻咽喉   4篇
儿科学   35篇
妇产科学   6篇
基础医学   68篇
口腔科学   35篇
临床医学   76篇
内科学   245篇
皮肤病学   11篇
神经病学   6篇
特种医学   222篇
外科学   35篇
综合类   15篇
预防医学   21篇
眼科学   15篇
药学   23篇
肿瘤学   41篇
  2023年   10篇
  2022年   2篇
  2021年   6篇
  2020年   13篇
  2019年   14篇
  2018年   16篇
  2017年   15篇
  2016年   12篇
  2015年   13篇
  2014年   20篇
  2013年   21篇
  2012年   20篇
  2011年   11篇
  2010年   32篇
  2009年   28篇
  2008年   15篇
  2007年   19篇
  2006年   9篇
  2005年   14篇
  2004年   9篇
  2003年   3篇
  2002年   8篇
  2001年   4篇
  2000年   11篇
  1999年   5篇
  1998年   45篇
  1997年   56篇
  1996年   51篇
  1995年   46篇
  1994年   46篇
  1993年   30篇
  1992年   11篇
  1991年   9篇
  1990年   11篇
  1989年   19篇
  1988年   30篇
  1987年   13篇
  1986年   29篇
  1985年   26篇
  1984年   12篇
  1983年   18篇
  1982年   18篇
  1981年   10篇
  1980年   10篇
  1979年   2篇
  1978年   6篇
  1977年   10篇
  1976年   15篇
  1975年   4篇
  1969年   1篇
排序方式: 共有858条查询结果,搜索用时 0 毫秒
71.
Serial immunoreactive erythropoietin levels in autologous blood donors   总被引:1,自引:0,他引:1  
The variations in plasma erythropoietin (EPO) concentration during preoperative deposit of autologous blood were studied in 12 patients (8 men, 4 women). Four donations were scheduled at weekly intervals. A predonation hemoglobin concentration of 11 g per dL (110 g/L) was required. Hemoglobin concentration decreased from 14.3 +/- 1.1 g per dL (143 +/- 11 g/L) (mean +/- SD) before the first donation to 11.7 +/- 0.7 g per dL (117 +/- 7 g/L) on Day 22 (p less than or equal to 0.0001). Reticulocyte counts increased from a median of 31,800 (range, 4900-95,000) per microL (median, 32 x 10(9)/L [range, 5-95 x 10(9)/L]) to 93,800 (16,800-194,900) per microL (median, 94 x 10(9)/L [range, 17-195 x 10(9)/L]) on Day 28 (p less than or equal to 0.01). Plasma EPO concentration was 17.8 +/- 5.1 mU per mL prior to the first donation and displayed a small and transient peak after each donation. A sustained elevation followed each peak. Although plasma EPO concentration differed significantly from the baseline value after the first donation, only the peak concentrations after the second (35.5 +/- 15.5 mU/mL), third (38.0 +/- 14.5 mU/mL), and fourth (36.1 +/- 11.0 mU/mL) donations exceeded the normal range. The moderate, biphasic increase in plasma EPO concentration and the moderate increase in erythropoiesis suggest two strategies in autologous blood donation that should be investigated with respect to efficiency and safety: 1) more aggressive donation schemes, which reduce donation intervals and/or the minimum hemoglobin concentration and 2) the administration of recombinant human EPO.  相似文献   
72.
Adverse reactions in blood donors with a history of seizures or epilepsy   总被引:1,自引:0,他引:1  
BACKGROUND: Individuals with epilepsy or seizure disorders are restricted from donating blood because of concern that they are prone to adverse donor reactions such as syncope and convulsions. A study evaluating whether that concern is warranted is reported. STUDY DESIGN AND METHODS: During a 2-year period beginning in 1987, blood donors in Maryland with a history of seizures were actively recruited by the American Red Cross. Adverse donor reactions were classified as "slight", indicating dizziness and nausea without loss of consciousness; "moderate," denoting syncope; and "severe," indicating convulsive syncope. RESULTS: There were 329,143 satisfactory blood donations; 613 individuals reporting a history of seizures donated blood a total of 723 times. Among donors with seizures, 186 (35.7%) were taking antiepileptic medication, and 61 (8.4%) had had one or more seizures in the preceding year. Individuals with seizures had a low incidence of adverse reactions (3.34%). Although this incidence was slightly higher than that in the entire population (2.24%), the difference was not significant. In particular, the risk of syncope with or without convulsive activity was low for people with seizures (0.21%) and not significantly greater than that in other donors (0.28%). CONCLUSION: Individuals with seizures or epilepsy are not at greater risk for adverse reactions after blood donation, and major restrictions on their participation as blood donors are not warranted.  相似文献   
73.
Patients with acute heart failure (AHF) require urgent in‐hospital treatment for relief of symptoms. The main reason for hospitalization is congestion, rather than low cardiac output. Although congestion is associated with a poor prognosis, many patients are discharged with persistent signs and symptoms of congestion and/or a high left ventricular filling pressure. Available data suggest that a pre‐discharge clinical assessment of congestion is often not performed, and even when it is performed, it is not done systematically because no method to assess congestion prior to discharge has been validated. Grading congestion would be helpful for initiating and following response to therapy. We have reviewed a variety of strategies to assess congestion which should be considered in the care of patients admitted with HF. We propose a combination of available measurements of congestion. Key elements in the measurement of congestion include bedside assessment, laboratory analysis, and dynamic manoeuvres. These strategies expand by suggesting a routine assessment of congestion and a pre‐discharge scoring system. A point system is used to quantify the degree of congestion. This score offers a new instrument to direct both current and investigational therapies designed to optimize volume status during and after hospitalization. In conclusion, this document reviews the available methods of evaluating congestion, provides suggestions on how to properly perform these measurements, and proposes a method to quantify the amount of congestion present.  相似文献   
74.
75.
76.
Platelets have a central role in the development of arterial thrombosis and subsequent cardiovascular events. An appreciation of this complex process has made antiplatelet therapy the cornerstone of cardiovascular disease management. However, numerous patients will experience a recurrent atherothrombotic vascular event despite adequate antiplatelet therapy. Individual differences in the rate of platelet activation and reactivity markedly influence normal hemostasis and the pathological outcome of thrombosis. Such an individual variability is largely determined by environmental and genetic factors. These are known to either hamper platelets' response to agonists, and thereby mimic the pharmacological modulation of platelet function or mask therapy effect and sensitize platelets. In this article, we reviewed the antiplatelet mechanisms of aspirin and clopidogrel and the possible role of different polymorphisms, which may affect the efficacy of antiplatelet therapy. Heterogeneity in the way patients respond to aspirin and clopidogrel may in part reflect variation in cyclooxygenase (COX)-1, COX-2, glycoprotein (GP) Ib alpha, GP Ia/IIa, GP IIb/IIIa, UGT1A6*2, P2Y1, P2Y12, CYP2C9, CYP3A4 and CYP3A5 genotypes.  相似文献   
77.
78.
79.
80.
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