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   47172篇
  免费   3811篇
  国内免费   111篇
耳鼻咽喉   380篇
儿科学   1910篇
妇产科学   1296篇
基础医学   6768篇
口腔科学   971篇
临床医学   6492篇
内科学   9166篇
皮肤病学   894篇
神经病学   4816篇
特种医学   1074篇
外科学   4146篇
综合类   408篇
一般理论   62篇
预防医学   5758篇
眼科学   673篇
药学   2652篇
  2篇
中国医学   54篇
肿瘤学   3572篇
  2024年   60篇
  2023年   424篇
  2022年   582篇
  2021年   1265篇
  2020年   942篇
  2019年   1400篇
  2018年   1534篇
  2017年   1203篇
  2016年   1331篇
  2015年   1405篇
  2014年   1786篇
  2013年   2624篇
  2012年   3656篇
  2011年   3788篇
  2010年   2071篇
  2009年   1832篇
  2008年   3057篇
  2007年   3145篇
  2006年   3092篇
  2005年   2900篇
  2004年   2812篇
  2003年   2579篇
  2002年   2322篇
  2001年   373篇
  2000年   266篇
  1999年   318篇
  1998年   525篇
  1997年   393篇
  1996年   349篇
  1995年   343篇
  1994年   269篇
  1993年   265篇
  1992年   186篇
  1991年   162篇
  1990年   145篇
  1989年   117篇
  1988年   124篇
  1987年   87篇
  1986年   93篇
  1985年   98篇
  1984年   100篇
  1983年   100篇
  1982年   128篇
  1981年   123篇
  1980年   103篇
  1979年   62篇
  1978年   66篇
  1977年   49篇
  1976年   45篇
  1972年   35篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
82.
83.
84.
85.
PURPOSE: The purpose of our study was to obtain a clear understanding of the various diagnoses within the closed neural tube defect (NTD) groups included in the large database of clients in our Spina Bifida Clinic and a clear picture of the outcomes for the various NTD groups. METHODS: One hundred and four clients with closed NTD were categorized using a classification system devised by Tortori-Donati et al. Various clinical markers were investigated, including ambulation and the need for orthoses and wheelchairs. RESULTS: Most clients are ambulatory, requiring an orthoses, but not a wheelchair, despite the high incidence of ankle/foot abnormalities. CONCLUSIONS: This classification system has enhanced our knowledge of this group of clients, provided a greater understanding of the varied outcomes of these children and clinical management required.  相似文献   
86.
The aim of this study was to assess the periodontal treatment needs at under 20 yr of age in the affluent area of Espoo, Finland, offering comprehensive public dental health care, as compared to a less advantaged area in Chiangmai, Thailand. In Espoo, 50 girls and 50 boys were examined in each age group of 7, 12 and 17 yr. In Chiangmai equal numbers of girls and boys were examined to obtain a group of 89 subjects aged 18.5 + 0.6 yr. According to the Community Periodontal Index of Treatment Needs (CPITN) the need of scaling increased in Espoo from 6% of the 7-yr-olds to 39% of the 17-yr-olds. Moderate pocketing (4-5 mm) occurred in one subject at age 12 and in three subjects at age 17. In Chiangmai, deep pockets (6 mm and over) were recorded for 1%, moderate pockets for a total of 44%, and dental calculus as the highest treatment need indicator in the remaining 55%, indicating a need for professional treatment in 100% of the group examined. The mean number of sextants requiring scaling was 0.6 per person at age 17 in Espoo as compared to 4.5 at 18.5 yr of age in Chiangmai. Three or more healthy sextants per subject were recorded for 47% of the 17-yr-olds in Espoo and for only 6% of the 18.5-yr-olds in Chiangmai. It was concluded that already at young age vast differences occur between periodontal treatment needs in industrialized and developing countries.  相似文献   
87.
OBJECTIVE: A growing body of data suggests that a significantly enhanced salivary cortisol response to waking may indicate an enduring tendency to abnormal cortisol regulation. Our objective was to apply the response test to a population already known to have long-term hypothalamo-pituitary-adrenocortical (HPA) axis dysregulation. We hypothesized that the free cortisol response to waking, believed to be genetically influenced, would be elevated in a significant percentage of cases, regardless of the afternoon Dexamethasone Suppression Test (DST) value. METHOD: Using the free cortisol response to waking and the short daytime profile, we tested 18 clinically stable, lithium-responsive subjects from our long-term naturalistic follow-up of monthly DSTs. These tests include salivary testing every 15 minutes during the first hour of waking, followed by samples taken at 3:00 PM and 8:00 PM. RESULTS: While clinically stable on lithium prophylaxis, patients with bipolar disorder (BD) showed a significantly enhanced salivary cortisol response to waking, compared with control subjects (P < 0.03). Cortisol levels 30 minutes after waking significantly exceeded those in the large normative data provided in the literature (P < 0.001). CONCLUSIONS: Our observations support the hypothesis that the free cortisol response to waking can reflect relatively enduring HPA dysregulation, even when lithium-responsive BD patients are clinically well and their DSTs are normal. Because the test is easy to administer, the free cortisol response to waking may hold promise as a marker in studies of high-risk families predisposed to, or at risk for, mood disorders.  相似文献   
88.
89.
90.
The subthalamic nucleus plays a pivotal role in the regulation of basal ganglia output. Recent electrophysiologic, lesion and immunocytochemical studies suggest that the subthalamic nucleus uses an excitatory amino acid as a neurotransmitter. After complete ablation of the subthalamic nucleus, we have examined the NMDA, AMPA, kainate and metabotropic subtypes of excitatory amino acid receptors in two major subthalamic projection areas (globus pallidus and substantia nigra pars reticulata) with quantitative autoradiography. Two weeks after ablation, binding sites for [3H]AMPA and [3H]kainate increased in substantia nigra pars reticulata ipsilateral to the lesion. In globus pallidus on the lesioned side, [3H]glutamate binding to the NMDA recognition site decreased. The results suggest that glutamate receptors regulate after interruption of subthalamic nucleus output.  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