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   167321篇
  免费   11586篇
  国内免费   739篇
耳鼻咽喉   1904篇
儿科学   4705篇
妇产科学   3390篇
基础医学   21610篇
口腔科学   3272篇
临床医学   17384篇
内科学   33986篇
皮肤病学   2360篇
神经病学   15306篇
特种医学   6099篇
外科学   24834篇
综合类   2239篇
现状与发展   1篇
一般理论   205篇
预防医学   16104篇
眼科学   3452篇
药学   11423篇
  2篇
中国医学   233篇
肿瘤学   11137篇
  2023年   905篇
  2022年   1493篇
  2021年   3442篇
  2020年   2012篇
  2019年   3304篇
  2018年   3913篇
  2017年   2800篇
  2016年   3034篇
  2015年   3549篇
  2014年   5182篇
  2013年   7792篇
  2012年   11414篇
  2011年   12029篇
  2010年   6708篇
  2009年   5989篇
  2008年   10453篇
  2007年   11244篇
  2006年   10726篇
  2005年   10762篇
  2004年   10188篇
  2003年   9571篇
  2002年   9322篇
  2001年   1491篇
  2000年   1218篇
  1999年   1610篇
  1998年   1935篇
  1997年   1574篇
  1996年   1457篇
  1995年   1397篇
  1994年   1177篇
  1993年   1185篇
  1992年   943篇
  1991年   953篇
  1990年   817篇
  1989年   793篇
  1988年   826篇
  1987年   772篇
  1986年   802篇
  1985年   871篇
  1984年   958篇
  1983年   918篇
  1982年   1182篇
  1981年   1195篇
  1980年   1014篇
  1979年   663篇
  1978年   704篇
  1977年   620篇
  1976年   535篇
  1975年   484篇
  1974年   485篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Resection of the adrenal glands precludes participation in many immunotherapy protocols for metastatic renal cell carcinoma. We performed radical nephrectomy with adrenalectomy and contralateral partial adrenalectomy, including adrenal vein ligation for a 4 cm. hilar metastasis without perioperative complications or local recurrence after 30 months. Adrenal function, measured by cosyntropin stimulation tests 6 weeks and 10 months postoperatively, was normal. Partial adrenalectomy with preservation of adrenal function is possible.  相似文献   
102.
Abstract. During the 1997 Congress on Gerontology the issue of advocacy was prominently raised in numerous sessions. The delegates affirmed the Declaration of Adelaide, an important statement which called attention to the policy implications of scientific findings. The Declaration set research, practice and education agendas and urged increased resources for gerontological research and programs affecting the well-being of older persons and their families. The wisdom of “linking what we know and can do with what we hope for and desire,” as the theologian Jurgen Moltman has written, requires a systematic effort on the part of gerontologists to influence public policy, standards and professional practice. In short, gerontologists must become advocates. To be effective advocates they must raise awareness of critical issues, form coalitions with those who share the goal of a better world, and exchange information and best practices if the elders of society today - and those who will be the elders of tomorrow - are to benefit from science translated into sound policies and effective practices. Gerontologists must take their scientific findings - and questions - to the forums where policies are discussed and standards and practices developed.  相似文献   
103.
There are conflicting reports on the relationship between cerebellar vermal lobule hypoplasia and autism. Using quantitative magnetic resonance image analysis, we measured the cerebellar vermis in 125 normal individuals with a broad age range and 102 patients with a variety of neurogenetic abnormalities. We conclude that hypoplasia of cerebellar vermal lobules VI and VII is a nonspecific finding that even occurs in several conditions without autistic behavior. This suggests that it is not a specific neuroanatomical marker for autism, nor is cerebellar dys- genesis likely to be solely responsible for clinical autistic behaviors.  相似文献   
104.
Objective. 1. To identify risk factors associated with psychiatric rehospitalization within six months, using global clinical assessments and demographic information and; 2. To determine if risk factors for a hospital in a rural region are similar to those reported for urban hospitals. Method. The setting was a psychiatric unit within a general hospital. All adult admissions for one year were assigned scores on the North Carolina Functional Assessment Scale (NCFAS) and the Global Assessment of Functioning (GAF) scale. Patients were interviewed six months after discharge to determine if they had been rehospitalized and to assign new NCFAS and GAF scores. Results. Significant risk of rehospitalization was predicted by: 1. NCFAS score >90; 2. history of prior hospitalization; 3. nursing home residence; 4. referral from a small community hospital and; 5. non-compliance with outpatient appointments. Conclusions. Global assessments and demographic information collected during an index admission can generate factors to identify patients at risk for rehospitalization within six months. History of prior admissions and non-compliance with outpatient treatment, reported as risk factors in urban settings, were found also to be risk factors in a rural region.He was formerly Assistant Professor, Center for Health Sciences Statistics, East Carolina University School of Medicine.  相似文献   
105.
We have previously shown that the morphological and biochemical maturation of developing rat hypothalamic dopaminergic neurons is accelerated when they are cocultivated with pituitary intermediate lobe cells, one of their targets. Only two subsets of hypothalamic dopaminergic neurons (arcuate, A12, and periventricular, A14, nuclei) may project to the pars intermedia. In order to determine whether the two populations are equally responsive to coculture conditions, we microdissected the hypothalamus of 17-day-old rat fetuses in two fragments containing cell bodies from the A12 and from the A14 regions, prepared neuronal cultures from both portions and incubated them separately with intermediate lobe cells. The presence of intermediate lobe cells increased tyrosine hydroxylase levels in both dopaminergic neuron subsets, but morphological differentiation was accelerated in dopaminergic neurons originating in the arcuate nucleus only. We then investigated whether physical contact between developing arcuate neurons and their target cells was a prerequisite of the morphological effect by interposing a semipermeable membrane between cultivated neurons and intermediate lobe cells in transwell culture dishes. The morphological effect was no longer observed under transwell coculture conditions, pointing to the involvement of membrane-bound molecules. Accordingly, the stimulating effect of coculture on arcuate dopaminergic neurons was completely abolished by the removal of polysialic acid on neural cell adhesion molecules by endoneuraminidase N treatment. Thus, maturation of A12 and A14 dopaminergic neurons exhibits differential susceptibility to intermediate lobe target cells, and polysialylated-NCAM is required for the contact-dependent effect.  相似文献   
106.
107.
We describe a novel human zinc finger cNDA, C2H2-171. This cDNA represents an mRNA which encodes a protein of 484 amino acids and a calculated molecular weight of 54 kD. Four zinc finger-like domains are found in the C-terminal end of the protein. At the N-terminus, C2H2-171 contains a POZ/tramtrack-like domain similar to that found in the tumor associated zinc finger proteins LAZ-3/BCL-6 and PLZ-F, as well as in non-zinc finger proteins. C2H2-171 RNA is preferentially expressed in the brain, and increases during the course of murine development, with maximal expression in the adult. C2H2-171 RNA is differentially expressed in brain regions, with the highest level of expression in the cerebellum. C2H2-171 RNA was expressed at high levels in primary cerebellar granule cell neurons compared to astrocytes. The gene encoding C2H2-171 is highly conserved in vertebrates, and maps to the terminus of human chromosome 1 (1q44-ter). This chromosomal location is associated with a number of cytogenetic aberrations including those involving brain developmental anomalies and tumorigenesis. These data suggest that C2H2-171 may play an important role in vertebrate brain development and function.  相似文献   
108.
109.
110.
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