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   2480697篇
  免费   204109篇
  国内免费   4576篇
耳鼻咽喉   35882篇
儿科学   76131篇
妇产科学   65288篇
基础医学   349411篇
口腔科学   73942篇
临床医学   223763篇
内科学   491373篇
皮肤病学   50898篇
神经病学   209778篇
特种医学   99088篇
外国民族医学   903篇
外科学   373248篇
综合类   57237篇
现状与发展   2篇
一般理论   1026篇
预防医学   202878篇
眼科学   57619篇
药学   184401篇
  4篇
中国医学   4933篇
肿瘤学   131577篇
  2019年   19885篇
  2018年   27836篇
  2017年   21441篇
  2016年   23074篇
  2015年   26245篇
  2014年   37503篇
  2013年   55856篇
  2012年   76448篇
  2011年   80496篇
  2010年   46702篇
  2009年   44375篇
  2008年   74817篇
  2007年   79584篇
  2006年   79891篇
  2005年   78077篇
  2004年   75064篇
  2003年   72134篇
  2002年   69879篇
  2001年   114665篇
  2000年   118543篇
  1999年   100189篇
  1998年   28723篇
  1997年   26237篇
  1996年   26109篇
  1995年   25161篇
  1994年   23706篇
  1993年   22120篇
  1992年   80465篇
  1991年   77467篇
  1990年   74554篇
  1989年   71822篇
  1988年   66748篇
  1987年   65642篇
  1986年   62137篇
  1985年   59162篇
  1984年   44811篇
  1983年   38131篇
  1982年   23191篇
  1981年   20590篇
  1979年   41740篇
  1978年   29268篇
  1977年   24597篇
  1976年   23046篇
  1975年   24236篇
  1974年   29930篇
  1973年   28316篇
  1972年   26445篇
  1971年   24353篇
  1970年   22980篇
  1969年   21330篇
排序方式: 共有10000条查询结果,搜索用时 625 毫秒
101.
102.
103.
104.
105.
106.
Porocarcinoma is an unusual, locally aggressive and potentially fatal neoplasm. Several cutaneous malignancies have been described in association with porocarcinoma, including squamous cell carcinoma, basal cell carcinoma and tricholemmal carcinoma. Previous reports have indicated that the occurrence of malignant tumours in combination with porocarcinoma is extremely rare, in particular with regard to Bowen disease (BD). We report an uncommon case of porocarcinoma occurring synchronously in a single BD lesion in a 63‐year‐old woman with multiple BD lesions. The clinical and histological findings confirmed this diagnosis.  相似文献   
107.
Advancement in microelectromechanical system has facilitated the microfabrication of polymeric substrates and the development of the novel class of controlled drug delivery devices. These vehicles have specifically tailored three dimensional physical and chemical features which together, provide the capacity to target cell, stimulate unidirectional controlled release of therapeutics and augment permeation across the barriers. Apart from drug delivery devices microfabrication technology’s offer exciting prospects to generate biomimetic gastrointestinal tract models. BioMEMS are capable of analysing biochemical liquid sample like solution of metabolites, macromolecules, proteins, nucleic acid, cells and viruses. This review summarized multidisciplinary application of biomedical microelectromechanical systems in drug delivery and its potential in analytical procedures.  相似文献   
108.
Objective: Polyunsaturated fatty acids n-3 (PUFA n-3) have shown effects in reducing tumor growth, in particular eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) abundantly present in fish oil (FO). When these fatty acids are provided in the diet, they alter the functions of the cells, particularly in tumor and immune cells. However, the effects of α-linolenic fatty acid (ALA), which is the precursor of EPA and DHA, are controversial. Thus, our objective was to test the effect of this parental fatty acid. Methods: Non-tumor-bearing and tumor-bearing Wistar rats (70 days) were supplemented with 1 g/kg body weight of FO or Oro Inca® (OI) oil (rich in ALA). Immune cells function, proliferation, cytokine production, and subpopulation profile were evaluated. Results: We have shown that innate immune cells enhanced phagocytosis capacity, and increased processing and elimination of antigens. Moreover, there was a decrease in production of pro-inflammatory cytokines (tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6)) by macrophages. Lymphocytes showed decreased proliferation capacity, increased cluster of differentiation 8 (CD8+) subpopulation, and increased TNF-α production. Conclusions: Oil rich in ALA caused similar immune modulation in cancer when compared with FO.  相似文献   
109.
Individuals with sudden unilateral deafness offer a unique opportunity to study plasticity of the binaural auditory system in adult humans. Stimulation of the intact ear results in increased activity in the auditory cortex. However, there are no reports of changes at sub-cortical levels in humans. Therefore, the aim of the present study was to investigate changes in sub-cortical activity immediately before and after the onset of surgically induced unilateral deafness in adult humans. Click-evoked auditory brainstem responses (ABRs) to stimulation of the healthy ear were recorded from ten adults during the course of translabyrinthine surgery for the removal of a unilateral acoustic neuroma. This surgical technique always results in abrupt deafferentation of the affected ear. The results revealed a rapid (within minutes) reduction in latency of wave V (mean pre = 6.55 ms; mean post = 6.15 ms; p < 0.001). A latency reduction was also observed for wave III (mean pre = 4.40 ms; mean post = 4.13 ms; p < 0.001). These reductions in response latency are consistent with functional changes including disinhibition or/and more rapid intra-cellular signalling affecting binaurally sensitive neurons in the central auditory system. The results are highly relevant for improved understanding of putative physiological mechanisms underlying perceptual disorders such as tinnitus and hyperacusis.  相似文献   
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