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   105241篇
  免费   29667篇
  国内免费   1098篇
耳鼻咽喉   2475篇
儿科学   2816篇
妇产科学   2465篇
基础医学   3516篇
口腔科学   5281篇
临床医学   26492篇
内科学   26597篇
皮肤病学   3343篇
神经病学   12880篇
特种医学   3795篇
外国民族医学   1篇
外科学   18942篇
综合类   212篇
现状与发展   40篇
一般理论   3篇
预防医学   13930篇
眼科学   2280篇
药学   1435篇
中国医学   38篇
肿瘤学   9465篇
  2024年   747篇
  2023年   5097篇
  2022年   1287篇
  2021年   3085篇
  2020年   5492篇
  2019年   2266篇
  2018年   7158篇
  2017年   7516篇
  2016年   8066篇
  2015年   8192篇
  2014年   10683篇
  2013年   12469篇
  2012年   4374篇
  2011年   4048篇
  2010年   7158篇
  2009年   9325篇
  2008年   3876篇
  2007年   2827篇
  2006年   3891篇
  2005年   2494篇
  2004年   1832篇
  2003年   1414篇
  2002年   1375篇
  2001年   1930篇
  2000年   1209篇
  1999年   1767篇
  1998年   2113篇
  1997年   1939篇
  1996年   1994篇
  1995年   1737篇
  1994年   1120篇
  1993年   938篇
  1992年   792篇
  1991年   662篇
  1990年   556篇
  1989年   544篇
  1988年   536篇
  1987年   403篇
  1986年   397篇
  1985年   323篇
  1984年   281篇
  1983年   344篇
  1982年   256篇
  1981年   222篇
  1980年   145篇
  1978年   137篇
  1977年   139篇
  1976年   105篇
  1974年   99篇
  1972年   89篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
Recent New Labour policy for the ‘modernisation’ of Government places a good deal of emphasis on decentralisation. This emphasis is particularly marked in relation to the organisation of primary care. However, like hospitals and other National Health Service institutions, primary care trusts (PCTs) are subject to a substantial raft of centrally established performance targets and indicators, including those which contribute to the public award of between zero and three performance ‘stars’. This raises questions about the extent to which employees can exercise autonomy in the context of rigid top‐down directives. This paper presents findings from a study using participant observation and interviews to examine the impact of a training course aimed ostensibly at increasing employee autonomy in an English PCT. The suggestion is that attempts to make employees more autonomous can be seen as a strategy for increasing central control based upon the internalisation by the employees of centrally promulgated values. The attraction of such strategies is that they may be potentially more effective and less costly than alternative strategies of direct control. However, the study suggests that the outcome of attempts by such methods as programmes to increase employee autonomy may be very different from those intended.  相似文献   
42.
43.
44.
45.
The purpose of this study was to determine the genetic characteristics of foot polydactyly and identify its inheritance pattern by analyzing familial pedigree. Five cases from 2 Korean families were studied: 1 is a family whose members have been affected for 4 generations and the other for 2 generations. Using peripheral blood samples, we performed chromosomal analysis using the banding technique with Giemsa stain and karyotyping. We investigated the shape and structure of 46 chromosomes, looking for translation, deletion, inversion, ring chromosome, and isochromosome abnormalities. All peripheral blood samples demonstrated no chromosomal abnormalities, though the genetic nature of foot polydactyly and a new genetic locus was identified recently by other studies. Familial pedigree analysis suggested that polydactyly was inherited as an autosomal dominant trait in the first family. The mode of inheritance for the second family could not be determined due to an insufficient number of family members. The result of this study brought us to the conclusion that, while genetic factors play a major role in polydactyly, other factors may contribute to its occurrence.  相似文献   
46.
Cerebrospinal fluid (CSF) from 7 patients with infantile spasms (mean age: 6.7 months) was collected before and after treatment with adrenocorticotropic hormone (ACTH). The concentration of neurotransmitter metabolites was analyzed using high-performance liquid chromatography and compared to the metabolite concentration in the CSF from 7 age-matched controls (mean age: 6.1 months). Pretreatment levels of CSF 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid, 3-methoxy-4-hydroxyphenyl glycol (MHPG), and kynurenine were significantly lower in infantile spasm patients compared to controls. Following treatment, marked increases in 5-HIAA and decreases in kynurenine levels were observed in the CSF of the 5 infants whose seizures were eliminated or reduced by ACTH. In the 2 nonresponders 5-HIAA levels decreased. The level of MHPG was reduced slightly in 5 infants, including the 2 nonresponders, and was increased in 2 responders. CSF homovanillic acid levels increased in 4 infantile spasm infants and decreased in 3 following ACTH. These data demonstrate that the presence of seizures in infantile spasms is associated with a significant decrease in serotonergic activity and that elimination of seizures by ACTH is accompanied by increased serotonin turnover. The simultaneous increase of 5-HIAA and decrease of kynurenine, an alternate metabolite of tryptophan, suggests an underlying disturbance of tryptophan metabolism in infantile spasms. The possibility that elimination of seizures by ACTH may be related to decreased production of certain kynurenine metabolites, particularly quinolinic acid, is discussed.  相似文献   
47.
Myelofibrosis with myeloid metaplasia (MMM) is currently classified as a classic (ie, BCR-ABL-negative) myeloproliferative disorder characterized by anemia, multiorgan extramedullary hematopoiesis, constitutional symptoms, and premature death from either leukemic transformation or other disease complications. Stem cell transplantation can be curative, but many patients either are not appropriate candidates or do not choose to accept the significant risks associated with transplantation. Current pharmacologic therapy has been beneficial mainly in terms of palliating disease-associated cytopenias, constitutional symptoms, splenomegaly, and other organ damage from excess myeloproliferation. Novel treatment strategies are under investigation, including targeted inhibition of JAK2V617F, the activating tyrosine kinase point mutation present in about half of patients with MMM. In this article, we review both the old and new pharmacologic options for MMM.  相似文献   
48.
49.
50.
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