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   154930篇
  免费   31606篇
  国内免费   2401篇
耳鼻咽喉   5220篇
儿科学   5458篇
妇产科学   2540篇
基础医学   3727篇
口腔科学   1531篇
临床医学   27161篇
内科学   48189篇
皮肤病学   7475篇
神经病学   15396篇
特种医学   6452篇
外科学   41460篇
综合类   316篇
现状与发展   73篇
一般理论   6篇
预防医学   7371篇
眼科学   3415篇
药学   1198篇
中国医学   14篇
肿瘤学   11935篇
  2024年   685篇
  2023年   4796篇
  2022年   1212篇
  2021年   3141篇
  2020年   6063篇
  2019年   2206篇
  2018年   7464篇
  2017年   7385篇
  2016年   8463篇
  2015年   8468篇
  2014年   15557篇
  2013年   15803篇
  2012年   5726篇
  2011年   5738篇
  2010年   10470篇
  2009年   14361篇
  2008年   5998篇
  2007年   4244篇
  2006年   6736篇
  2005年   3996篇
  2004年   3254篇
  2003年   2230篇
  2002年   2348篇
  2001年   3833篇
  2000年   3020篇
  1999年   3238篇
  1998年   3695篇
  1997年   3509篇
  1996年   3400篇
  1995年   3251篇
  1994年   1972篇
  1993年   1609篇
  1992年   1401篇
  1991年   1445篇
  1990年   1077篇
  1989年   1202篇
  1988年   1041篇
  1987年   870篇
  1986年   913篇
  1985年   739篇
  1984年   586篇
  1983年   568篇
  1982年   587篇
  1981年   474篇
  1980年   417篇
  1979年   343篇
  1978年   373篇
  1977年   446篇
  1975年   305篇
  1972年   326篇
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
101.
102.
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   
103.
104.
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   
105.
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   
106.
107.
108.
109.
110.
Clinical outcomes data can be used to facilitate patient management decisions, assess clinician and organizational performance, and to provide evidence for the effectiveness of surgery and rehabilitation. The validity of the inferences made from outcomes data are dependent on the validity of the outcomes measures themselves and the circumstances under which the data were collected, analyzed, and interpreted. Clinical outcomes may include measures of impairment of body structure and function, activity limitation, and participation restriction. However, because the relationship between impairment and the resulting activity limitation and participation restriction is not direct, and because activity limitations and participation restrictions are of the utmost concern to the athlete, the primary clinical outcome should be measures of activity limitation and participation restriction. Activity limitation and participation restriction may be measured either through direct observation of performance or by general or specific measures of health related quality of life. Clinical outcomes data must be collected systematically to ensure valid inferences from the data.  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