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   13901篇
  免费   921篇
  国内免费   563篇
耳鼻咽喉   178篇
儿科学   449篇
妇产科学   198篇
基础医学   1627篇
口腔科学   292篇
临床医学   1426篇
内科学   2994篇
皮肤病学   279篇
神经病学   903篇
特种医学   454篇
外国民族医学   2篇
外科学   1424篇
综合类   1134篇
一般理论   2篇
预防医学   1068篇
眼科学   486篇
药学   1132篇
  6篇
中国医学   354篇
肿瘤学   977篇
  2024年   24篇
  2023年   128篇
  2022年   252篇
  2021年   456篇
  2020年   306篇
  2019年   371篇
  2018年   544篇
  2017年   385篇
  2016年   374篇
  2015年   492篇
  2014年   576篇
  2013年   680篇
  2012年   995篇
  2011年   1069篇
  2010年   634篇
  2009年   443篇
  2008年   732篇
  2007年   834篇
  2006年   657篇
  2005年   721篇
  2004年   612篇
  2003年   593篇
  2002年   564篇
  2001年   470篇
  2000年   504篇
  1999年   396篇
  1998年   127篇
  1997年   109篇
  1996年   113篇
  1995年   93篇
  1994年   56篇
  1993年   60篇
  1992年   154篇
  1991年   119篇
  1990年   106篇
  1989年   110篇
  1988年   93篇
  1987年   75篇
  1986年   66篇
  1985年   50篇
  1984年   38篇
  1983年   23篇
  1982年   13篇
  1981年   10篇
  1980年   11篇
  1979年   14篇
  1977年   12篇
  1976年   9篇
  1973年   9篇
  1970年   9篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Mammalian brain development is controlled by thyroid hormone through the regulation of target genes. In this study, we describe for the first time that a splicing regulator gene is under thyroid hormone control in the rat brain during the critical period of neuronal differentiation. By differential display, we have identified the mammalian homolog of the Drosophila splicing regulator Suppressor-of-white-apricot (SWAP) as a thyroid hormone-regulated gene in an immortal line of rat neuroblasts, E18 cells. Using Northern blotting and in situ hybridization, we found that expression of SWAP is under thyroid control in the developing rat brain. SWAP gene expression is highest during the first 10 days of life (P0-P10), preferentially in cerebral cortex, cerebellum, subventricular epithelium, piriform cortex, hippocampus, amygdala, and caudate putamen. At later stages (P15-P30) SWAP expression decreases, being detectable only in the cerebellum, hippocampus, and layers II/III of cerebral and piriform cortexes. We found that hypothyroidism causes an abnormal high level of SWAP RNA expression at P5-P15 throughout the brain except the cerebellum. Significantly, thyroid hormone treatment in vivo of hypothyroid animals led to a normalization of SWAP RNA expression. Furthermore, similar hormone treatment caused a decrease in SWAP expression in control rats. By modulating the expression of SWAP and perhaps other splicing regulators thyroid hormone may exert wide regulatory effects on multiple genes. The regulation of SWAP gene defines a novel mechanism of action of thyroid hormone which can be important for its effects in the developing brain.  相似文献   
102.
103.
Mycoplasma pneumoniae infections usually produce respiratory symptoms, that only exceptionally involve the nervous system. In this case, the infection generally causes an encephalitic picture characterized by impaired consciousness and seizures, and by normal or non-specific neuroradiological findings. However, four cases of M. pneumoniae infection associated with symmetrical lesions in the putamen and its external surrounding areas, and with extrapiramidal symptoms, have been recently published. We present the case of a patient with a clinical picture characterized by confusion, fever, and seizures, associated with a M. pneumoniae infection. The MRI study showed two symmetrical lesions that involved the areas just outside the putamen and disappeared coinciding with her clinical improvement. The present case would support that the encephalopathy associated with the M. pneumoniae infection shows a tendency to involve a particular region of the brain. Our case might represent the minimal expression of these characteristic lesions, which in the most benign cases would involve the areas immediately outside the putamen, and in other instances the putamen as well.  相似文献   
104.
105.
106.
107.
108.
OBJECTIVE: To analyze food consumption patterns among schoolchildren in Cantabria and to compare results obtained with Spanish food guidelines for this population group. METHODS: A food frequency questionnaire was the chosen method, with some 53 food types divided into 15 groups. A total of 1,205 teenagers of both sexes aged between 14 and 18 attending 18 secondary schools in Cantabria completed the questionnaire. RESULTS: Milk, bread, fruit, greens and vegetables are the foodstuffs mostly consumed at the recommended frequencies. On the other hand, fish, meat, eggs, dairy products and pulse make up the least adequately consumed categories. Alcoholic drinks are imbibed to a high degree, with beer being the alcoholic most frequently drunk. Spirits are also drunk in larger quantities than wine. Alcohol consumption (beer, wines and spirits) increases significantly with age, being higher among males than females. CONCLUSIONS: Cantabrian schoolchildren follow a food consumption pattern which, generally speaking, does not tally with Spanish food recommendations for their age group. Educational and interventional strategies need to be developed with the aim of modifying such inappropriate food consumption.  相似文献   
109.
The modulating effect of dietary enrichment in mistol seed oil (MO) containing 25% of alpha-linolenic acid (ALA), evening primrose oil (EPO) enriched in gamma-linolenic acid (GLA) and corn oil (CO) as sources of omega-6 and omega-9 fatty acids on the growth parameters of one transplantable mammary tumor were compared. Mice fed on different lipid formulae were inoculated with a mammary gland adenocarcinoma and different growth development tumor parameters were recorded. Results showed that corn oil feeding slowed down most of the tumor growth parameters, as did the EPO diet. MO also showed antitumor activity. Olein feeding, which induces an essential fatty acid deficiency (EFAD), increased the incidence and the multiplicity of metastases when compared with the controls. It may be concluded that a diet enriched in omega-6 fatty acids did not behave as a tumor promoter in this mammary gland tumor model. The antitumor activities of EPO and MO are corroborated in present experiments, suggesting that both oils may be of value in nutritional approaches of mammary gland tumor therapies. In addition, present data add further experimental proof about the proposed protumorigenic proneness induced by the EFAD state.  相似文献   
110.
冠心病的范围包括(1)静寂性(即无痛性)心肌缺血,(2)慢性稳定型心绞痛,(3)不稳定型心绞痛,(4)非透壁性心肌梗死及(5)急性透壁性心肌梗死等五种。近年研讨的热点为不稳定型心绞痛及急性心肌梗死的临床诊断及治疗。 一、不稳定型心绞痛 不稳定型心绞痛既无心电图的特征性图象,也无心肌酶的增高。它的界定必须依  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