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   34586篇
  免费   9250篇
  国内免费   190篇
耳鼻咽喉   335篇
儿科学   914篇
妇产科学   681篇
基础医学   6365篇
口腔科学   1150篇
临床医学   4671篇
内科学   8348篇
皮肤病学   731篇
神经病学   2892篇
特种医学   1965篇
外科学   7605篇
综合类   363篇
一般理论   15篇
预防医学   3583篇
眼科学   555篇
药学   1868篇
  1篇
中国医学   44篇
肿瘤学   1940篇
  2021年   599篇
  2020年   418篇
  2019年   423篇
  2018年   663篇
  2017年   619篇
  2016年   771篇
  2015年   1123篇
  2014年   1827篇
  2013年   2546篇
  2012年   1251篇
  2011年   1179篇
  2010年   1557篇
  2009年   1590篇
  2008年   957篇
  2007年   823篇
  2006年   916篇
  2005年   798篇
  2004年   715篇
  2003年   616篇
  2002年   643篇
  2001年   760篇
  2000年   675篇
  1999年   872篇
  1998年   894篇
  1997年   843篇
  1996年   889篇
  1995年   846篇
  1994年   733篇
  1993年   660篇
  1992年   789篇
  1991年   763篇
  1990年   675篇
  1989年   752篇
  1988年   737篇
  1987年   741篇
  1986年   683篇
  1985年   684篇
  1984年   606篇
  1983年   574篇
  1982年   613篇
  1981年   583篇
  1980年   549篇
  1979年   564篇
  1978年   545篇
  1977年   539篇
  1976年   468篇
  1975年   422篇
  1974年   390篇
  1973年   369篇
  1972年   362篇
排序方式: 共有10000条查询结果,搜索用时 109 毫秒
61.
62.
63.
64.
65.
66.
Complement is a multifunctional system of receptors and regulators as well as effector molecules. Both the pathogenic and diagnostic power of complement is based on the capacity of the complement system to amplify innate and adaptive immunity. This amplification is accomplished through two strategies: (1) enzymatic reactions in the complement cascade, and (2) stimulation of leukocytes, platelets and parenchymal cells through specific receptors or receptor-independent pore formation. The mechanisms by which complement mediates and modifies nonspecific inflammation, antibody-mediated injury and T-cell responses are of particular significance to the pathogenesis of transplant rejection. Understanding the mechanisms by which complement integrates the interactions of leukocytes, platelets and parenchymal cells offers opportunities to further refine the diagnosis of rejection.  相似文献   
67.
Objectives: Little is known about recent trends in U.S. emergency department (ED) visits for acute exacerbation of chronic obstructive pulmonary disease (AECOPD) or about ED management of AECOPD. This study aimed to describe the epidemiology of ED visits for AECOPD and to evaluate concordance with guideline‐recommended care. Methods: Data were obtained from National Hospital Ambulatory Medical Care Survey (NHAMCS). ED visits for AECOPD, during 1993 to 2005, were identified using the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD‐9‐CM) codes. Concordance with guideline recommendations was evaluated using process measures. Results: Over the 13‐year study period, there was an average annual 0.6 million ED visits for AECOPD, and the visit rates for AECOPD were consistently high (3.2 per 1,000 U.S. population; Ptrend = 0.13). The trends in the use of chest radiograph, pulse oximetry, or bronchodilator remained stable (all Ptrend > 0.5). By contrast, the use of systemic corticosteroids increased from 29% in 1993–1994 to 60% in 2005, antibiotics increased from 14% to 42%, and methylxanthines decreased from 15% to <1% (all Ptrend < 0.001). Multivariable analysis showed patients in the South (vs. the Northeast) were less likely to receive systemic corticosteroids (odds ratio [OR] = 0.6; 95% confidence interval [CI] = 0.4 to 0.9). Conclusions: The high burden of ED visits for AECOPD persisted. Overall concordance with guideline‐recommended care for AECOPD was moderate, and some emergency treatments had improved over time.  相似文献   
68.
69.
Acute myelogenous leukemia (AMU is a hematologic disorder that is characterized by an abnormal proliferation of immature myeloid cells. Granulocytic sarcomas are clusters of leukemic myeloid cells that may develop as a result of AML. Oral manifestations of AML are common and often involve enlargements of the gingiva and/or mucosal tissue from direct leukemia cell infiltration. We describe the case history of a 50-year-old man who had an ulcera-tive lesion of the oral mucosa that was determined to be a granulocytic sarcoma of AML-M0 subtype. The combination of both the subtype and clinical presentation of the leukemia makes this presentation unusual, and to the best of our knowledge, of a type that has not been previously reported in the literature.  相似文献   
70.
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