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   4010篇
  免费   205篇
  国内免费   13篇
耳鼻咽喉   86篇
儿科学   113篇
妇产科学   37篇
基础医学   545篇
口腔科学   229篇
临床医学   345篇
内科学   680篇
皮肤病学   76篇
神经病学   396篇
特种医学   174篇
外科学   576篇
综合类   10篇
一般理论   1篇
预防医学   321篇
眼科学   123篇
药学   239篇
中国医学   4篇
肿瘤学   273篇
  2024年   4篇
  2023年   34篇
  2022年   54篇
  2021年   104篇
  2020年   77篇
  2019年   90篇
  2018年   108篇
  2017年   59篇
  2016年   122篇
  2015年   105篇
  2014年   137篇
  2013年   206篇
  2012年   273篇
  2011年   263篇
  2010年   156篇
  2009年   145篇
  2008年   300篇
  2007年   275篇
  2006年   302篇
  2005年   248篇
  2004年   225篇
  2003年   228篇
  2002年   210篇
  2001年   32篇
  2000年   21篇
  1999年   33篇
  1998年   52篇
  1997年   32篇
  1996年   30篇
  1995年   30篇
  1994年   32篇
  1993年   35篇
  1992年   20篇
  1991年   13篇
  1990年   10篇
  1989年   13篇
  1988年   14篇
  1987年   9篇
  1986年   9篇
  1985年   13篇
  1984年   13篇
  1983年   14篇
  1982年   10篇
  1981年   10篇
  1980年   8篇
  1979年   12篇
  1978年   12篇
  1977年   4篇
  1975年   4篇
  1974年   4篇
排序方式: 共有4228条查询结果,搜索用时 15 毫秒
41.
42.
43.
44.
Recent developments of optogenetic tools and fluorescence-based calcium recording techniques enable the manipulation and monitoring of neural circuits on a cellular level. Non-invasive imaging of brain networks, however, requires the application of methods such as blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI), which is commonly used for functional neuroimaging. While BOLD fMRI provides brain-wide non-invasive reading of the hemodynamic response, it is only an indirect measure of neural activity. Direct observation of neural responses requires electrophysiological or optical methods. The latter can be combined with optogenetic control of neuronal circuits and are MRI compatible. Yet, simultaneous optical recordings are still limited to fiber-optic-based approaches. Here, we review the integration of optical recordings and optogenetic manipulation into fMRI experiments. As a practical example, we describe how BOLD fMRI in a 9.4-T small animal MR scanner can be combined with in vivo fiber-optic calcium recordings and optogenetic control in a multimodal setup. We present simultaneous BOLD fMRI and calcium recordings under optogenetic control in rat. We outline details about MR coil configuration, choice, and usage of opsins and chemically and genetically encoded calcium sensors, fiber implantation, appropriate light power for stimulation, and calcium signal detection, to provide a glimpse into challenges and opportunities of this multimodal molecular neuroimaging approach.  相似文献   
45.
46.
Mobile technology has been increasingly adopted in promotion of mental health among older people. This study assessed the feasibility of a mobile mental wellness training application for individual use and for group work from the perspectives of older adults and social care professionals. The older individuals recruited for the study were participants in a Circle of Friends group and family caregivers' peer support group offered by the communal senior services. The qualitative and quantitative results of interviews, questionnaires, observation, and application usage were reported. Seven older adults started using the application independently at home in parallel with the group activity. This study revealed new information regarding the barriers to the older adults' full adoption of such mobile technologies. The results indicated that there may be potential in the incorporation of mobile technologies in promotion of mental health of older people at group settings.  相似文献   
47.
48.
Several growth factors and cytokines are involved in regulation of the immediate repair of gastrointestinal mucosa, a process also called restitution. Few data exist on the effect of inflammation on this process using an explant model, where the folded basal lamina is included. The aim of the present study was to investigate the effect of simulated inflammation on restitution and on concomitant proliferation and apoptosis in isolated guinea pig gastric mucosa. Paired gastric mucosae were mounted in Ussing chambers (37 degrees C) and a superficial injury was induced (1.25 M NaCl/5 min) followed by a 4-hr restitution (pH 7.3-7.5). During perfusion, simulated inflammation was induced (with 0.5 or 5.0 ng/ml IL-1beta or with activated polymorphonuclear [PMN] cells). The PI (proliferative index) and AI (apoptotic index) are expressed as the number of Mib-1- or Bax-immunopositive cells per 300 foveolar cells, respectively. The mean recovery of electrophysiological resistance of tissues (R) after injury and exposure to serosal IL-1beta during restitution was 95.2 +/- 5.3% (mean +/- SD), whereas the value for control tissues was 89.6 +/- 6.9% (P = 0.016; N = 9). The mean recovery of R in tissues exposured to activated serosal PMN cells during restitution was 97.6 +/- 2.7%, whereas the value for unexposed control tissues was 93.8 +/- 2.9 (P = 0.004; N = 9). The enhancing effect of PMN cells was partially eliminated by serosal anti-ICAM, whereas serosal cytochalasin D abolished the process completely. The PI of tissues exposed to serosal PMN cells was 34.6 +/- 17.3, whereas the value for unexposed controls was 24.7 +/- 15.5 (P = 0.04; N = 5). The corresponding AI values were 17.0 +/- 2.8 and 12.0 +/- 5.7, respectively (NS; N = 4). Simulated inflammation either with serosal IL-1beta or with activated PMN cells enhances restitution and proliferation, whereas their effect on AI is only suggestive. Exogenous serosal anti-ICAM modulates restitution, whereas cytochalasin D abolishes it completely, suggesting that the structural signaling system including focal adhesions and cytoskeleton plays a significant role in the regulation of restitution.  相似文献   
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