首页 | 官方网站   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   15990篇
  免费   1326篇
  国内免费   489篇
医药卫生   17805篇
  2024年   31篇
  2023年   173篇
  2022年   427篇
  2021年   601篇
  2020年   334篇
  2019年   435篇
  2018年   431篇
  2017年   380篇
  2016年   393篇
  2015年   545篇
  2014年   635篇
  2013年   695篇
  2012年   1132篇
  2011年   1204篇
  2010年   712篇
  2009年   606篇
  2008年   878篇
  2007年   854篇
  2006年   821篇
  2005年   775篇
  2004年   698篇
  2003年   598篇
  2002年   520篇
  2001年   467篇
  2000年   402篇
  1999年   398篇
  1998年   151篇
  1997年   153篇
  1996年   178篇
  1995年   147篇
  1994年   107篇
  1993年   85篇
  1992年   195篇
  1991年   182篇
  1990年   157篇
  1989年   136篇
  1988年   129篇
  1987年   107篇
  1986年   105篇
  1985年   103篇
  1984年   77篇
  1983年   70篇
  1982年   56篇
  1981年   55篇
  1980年   47篇
  1979年   60篇
  1978年   50篇
  1977年   33篇
  1975年   27篇
  1974年   43篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
3.
4.
Mycophenolate mofetil (MMF) used in a triple-drug regimen has been shown to decrease acute rejection rates, compared to a double-drug regimen. The impact of MMF on late acute rejection (LAR) episodes has not been well described. To investigate the risk of LAR (rejection > or = 6 months post-transplantation) data from the Scientific Registry of Transplant Recipients (SRTR) were used. We studied adult primary liver transplant recipients transplanted between June 1, 1995, and April 30, 2004, with hepatitis C virus (HCV) (n = 3356), hepatitis B virus (HBV) (n = 550) or a nonviral (n = 5740) primary cause of liver disease who were recorded as receiving continuous 3-(MMF + Tacro + steroids) versus 2-drug (Tacro + steroids) therapy for at least 6 months immediately post transplantation. Kaplan-Meier analysis showed significantly lower LAR rates 4 years post-transplant in 3- versus 2-drug HCV, HBV and nonviral disease patients. Multivariate regression confirmed 3- versus 2-drug therapy to be associated with a decreased risk of LAR. Late graft survival was significantly lower at 4 years post-transplant for patients with LAR 6-12 months post-transplantation versus patients with early rejection (78.0% vs. 87.0%, p < 0.001) and no rejection (88.1%, p < 0.001). Three-drug versus 2-drug therapy for a minimum of 6 months may offer a better treatment strategy to avoid the consequences and expense of LAR episodes.  相似文献   
5.
6.
研究大学生心理素质与思想品德发展的关系,目的在于分析、发现个体在接受教育过程中的心理运动规律,从而提高思想教育的实效性。本文从马克思主义认识论和实践论的观点出发,依据教育心理学的原理,探讨了心理健康教育与思想品德教育的内在联系和相互作用,提出良好的心理素质是大学生思想品德发展的基础的观点。认为品德的形成与人的心理活动息息相关,个体如果没有良好的品德,将影响其心理素质的完善;同样,没有健全的心理素质,思想品德也不能得到很好的发展。只有思想品德教育与心理健康教育协调发展,共同作用,才能收到良好的教育效果。  相似文献   
7.
8.
PURPOSE: Videofluorography (VF) and endoscopy are commonly used for dynamic imaging (DI) of pharyngeal swallowing but do not offer transverse plane (TP) information. The aim of the present study was to evaluate helical computerized tomography (HCT) to measure the DI capability pharyngeal swallowing in the TP. METHODS: The HCT scan technique used was a single-slice cine mode with scan times of 100 ms. All 15 subjects were studied supine during dry swallow, swallowing of barium sulphate jelly and 3, 10, 15 or 20 ml of a 40% barium sulphate solution. Nine subjects repeated the test twice at more than 1 week's interval to determine the test-retest reliability. RESULTS: Swallowing leads to closure of the vocal folds, pharyngeal constriction and narrowing of the piriform sinuses allowing jelly passage between the sinuses. Laryngeal elevation then occurs with the opening of the pharyngoesophageal segment (PES). Swallowing a bolus of 20 ml produced the maximum anteroposterior and transverse diameters as well as the maximum opening area of the PES. The test-retest intraclass correlation coefficients with liquid deglutition ranged from 0.86 to 0.98. CONCLUSIONS: This study shows that HCT enables visualization of TP of PES complementing VF or endoscopic swallowing studies.  相似文献   
9.
10.
PURPOSE: To describe the management of severe acute intracardiac thrombosis in a patient who underwent redo multiple valve replacement and valvular repair. The diagnostic features, associated risk factors, and anesthetic management are reviewed. CLINICAL FEATURES: A 67-yr-old woman undergoing redo mitral and aortic mechanical valve replacement and tricuspid annuloplasty under aprotinin prophylaxis exhibited severe refractory hypotension that began immediately after protamine reversal of intraoperative heparin anticoagulation following separation from cardiopulmonary bypass. Intraoperative transesophageal echocardiography revealed severe thrombosis in the right atrium, right ventricle and pulmonary artery. The patient was managed by immediate reheparinization and return to cardiopulmonary bypass (CPB), surgical thrombectomy, and intraoperative administration of recombinant tissue-plasminogen activator. After removal of the thrombi, and separation from CPB, no further protamine was given. One hundred units of blood products and two surgical re-explorations were required to manage subsequent massive postoperative bleeding. Acute heparin-induced thrombocytopenia (HIT) was ruled out using sensitive assays for HIT antibodies. After 16 days in the intensive care unit and 30 more days in hospital, the patient was subsequently transferred to a chronic care facility and succumbed several weeks later. CONCLUSION: Acute intraoperative thrombosis is a rare and potentially fatal complication of cardiac surgery. Intraoperative transesophageal echocardiography was essential for rapid diagnosis in this case. Multiple interacting prothrombotic factors (e.g., aprotinin use, acquired antithrombin deficiency, long pump time, post-protamine status, transfusion of blood components) were likely contributing factors related to this rare complication.  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-23

京公网安备 11010802026262号