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   3365326篇
  免费   255730篇
  国内免费   8825篇
耳鼻咽喉   45612篇
儿科学   110229篇
妇产科学   91980篇
基础医学   474362篇
口腔科学   94313篇
临床医学   309365篇
内科学   661584篇
皮肤病学   77270篇
神经病学   278179篇
特种医学   131020篇
外国民族医学   952篇
外科学   503790篇
综合类   72914篇
现状与发展   5篇
一般理论   1297篇
预防医学   266007篇
眼科学   74889篇
药学   247024篇
  11篇
中国医学   6629篇
肿瘤学   182449篇
  2019年   26192篇
  2018年   36933篇
  2017年   28342篇
  2016年   32610篇
  2015年   36772篇
  2014年   50968篇
  2013年   76984篇
  2012年   101843篇
  2011年   108029篇
  2010年   65106篇
  2009年   62323篇
  2008年   100753篇
  2007年   107269篇
  2006年   109099篇
  2005年   104897篇
  2004年   101134篇
  2003年   97508篇
  2002年   93894篇
  2001年   162130篇
  2000年   166535篇
  1999年   140114篇
  1998年   40461篇
  1997年   35984篇
  1996年   36433篇
  1995年   35417篇
  1994年   32675篇
  1993年   30566篇
  1992年   110438篇
  1991年   106642篇
  1990年   103299篇
  1989年   99449篇
  1988年   91388篇
  1987年   89782篇
  1986年   84464篇
  1985年   80709篇
  1984年   60469篇
  1983年   51181篇
  1982年   30440篇
  1981年   27269篇
  1979年   53960篇
  1978年   38358篇
  1977年   32378篇
  1976年   30076篇
  1975年   32093篇
  1974年   38078篇
  1973年   36315篇
  1972年   33918篇
  1971年   31494篇
  1970年   28953篇
  1969年   27551篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
991.
The aim of the present study was to explore differences in the clinical expression, clinical diagnoses and management of airway diseases in a primary-care setting. Patients aged >or=35 yrs who had ever smoked were enrolled when they presented for any reason to one of eight rural primary-care practices. Respiratory symptom questionnaires and spirometry were administered. In total, 1,034 patients had acceptable and reproducible spirometry, of whom 550 (53%) were males and 484 (47%) were females. Males smoked more than females (41.2 versus 29.2 pack-yrs) respectively, and were more likely to have a pre-bronchodilator forced expiratory volume in one second/forced vital capacity <0.70 at 22.4 versus 11.8%, respectively. However, more females than males reported breathlessness (51.0 versus 42.8%, respectively), a prior diagnosis compatible with airflow obstruction and taking respiratory medications (23.4 versus 14.9%, respectively). In conclusion, the current results suggest that females are more likely than males to report breathlessness and be prescribed respiratory medications independent of differences in the severity of airflow obstruction.  相似文献   
992.
There are no data available combining transbronchial needle aspiration (TBNA) of mediastinal lymph nodes and positron emission tomography (PET) in the staging of nonsmall cell lung cancer (NSCLC). The aim of the current study was to determine if these two methods can enhance the negative predictive value of the individual modality alone, for a specific lymph node station, and if this integrated approach can reduce the number of mediastinoscopies. A total of 113 patients with enlarged mediastinal lymph nodes (> or = 1 cm), who underwent both TBNA and PET scanning, were included. In 51 patients, histopathology, confirmed by surgical lymph node dissection, was compared with PET results and TBNA. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy to detect malignant lymphadenopathy was 68 (13/19), 89 (119/134), 46 (13/28), 95 (119/125) and 86% (132/152) for PET, respectively; 54% (6/11), 100 (53/53), 100 (6/6), 91 (53/58) and 92% (59/64), respectively for TBNA; and 100 (11/11), 94 (50/53), 79 (11/14), 100 (50/50) and 95 (61/64) for combined TBNA and PET, respectively. Combination of transbronchial needle aspiration and positron emission tomography has the potential to allow adequate mediastinal staging of nonsmall cell lung cancer with enlarged lymph nodes in most patients without the need for mediastinoscopy.  相似文献   
993.
994.
最近提出的关于额叶功能的理论认为前额叶皮质,尤其是其背外侧面在确定适合一项特殊任务的一系列反应中起重要作用,并在选择中使上述反应发生偏差。这些活动事实上是为任何类型的非常规任务而执行,而不考虑内容的差别。本研究旨在通过一项解决“洞察力”问题的测试任务(即火柴杆算术作业),来验证Frith“塑造反应空间”假说的预测效力。从Knoblich等人对健康人不能解决火柴杆问题的解释和Frith关于额叶背外侧皮质作用的理论,作者推导出与直觉相左的预测,即对这些相对复杂的任务,外侧额叶皮质局部损伤的患者可能比1组健康受试者完成得更好。要求35例经CT或MRI扫描证实为单个局部脑损伤的患者(年龄为26—65岁)和23例健康受试者(年龄为34—62岁)完成火柴杆作业。研究结果似乎与理论上的预测相一致,虽然仅有43%的健康受试者能解决最困难的火柴杆问题(“C类”),但是却有82%的额叶外侧损伤患者完成了类似问题(Fisher精确概率检验,P〈0.05)。总之,对Frith和Knoblich等人理论的结合进行了确证。  相似文献   
995.
996.
997.
A national conference on organ donation after cardiac death (DCD) was convened to expand the practice of DCD in the continuum of quality end-of-life care. This national conference affirmed the ethical propriety of DCD as not violating the dead donor rule. Further, by new developments not previously reported, the conference resolved controversy regarding the period of circulatory cessation that determines death and allows administration of pre-recovery pharmacologic agents, it established conditions of DCD eligibility, it presented current data regarding the successful transplantation of organs from DCD, it proposed a new framework of data reporting regarding ischemic events, it made specific recommendations to agencies and organizations to remove barriers to DCD, it brought guidance regarding organ allocation and the process of informed consent and it set an action plan to address media issues. When a consensual decision is made to withdraw life support by the attending physician and patient or by the attending physician and a family member or surrogate (particularly in an intensive care unit), a routine opportunity for DCD should be available to honor the deceased donor's wishes in every donor service area (DSA) of the United States.  相似文献   
998.
999.
目的:在瑞典儿童群体中,研究瑞典语译的出院后行为学问卷调查(PHBQ)的有效性和可行性。方法:利用回译的方法,将PHBQ翻译成瑞典语。340名2~13岁间的小儿被纳入研究对象,均曾有过麻醉下接受选择性外科手术或诊断过程的住院史。利用旋光性甲戊炔醇主成分分析的探测性因素分析法分析结果。选择一匹配于该模型的可靠的适合度测量法,利用证实性的因素分析,检查数据的适合度(所有因素P〉0.09)。  相似文献   
1000.
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