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   2348764篇
  免费   175125篇
  国内免费   3330篇
耳鼻咽喉   32056篇
儿科学   75951篇
妇产科学   62701篇
基础医学   348522篇
口腔科学   63638篇
临床医学   211458篇
内科学   457888篇
皮肤病学   51786篇
神经病学   185516篇
特种医学   88052篇
外国民族医学   489篇
外科学   354300篇
综合类   47523篇
现状与发展   12篇
一般理论   848篇
预防医学   182763篇
眼科学   54337篇
药学   175261篇
  11篇
中国医学   4577篇
肿瘤学   129530篇
  2021年   19021篇
  2019年   19570篇
  2018年   27099篇
  2017年   20383篇
  2016年   22784篇
  2015年   25662篇
  2014年   36148篇
  2013年   54020篇
  2012年   74767篇
  2011年   79521篇
  2010年   47140篇
  2009年   44622篇
  2008年   74715篇
  2007年   79565篇
  2006年   80401篇
  2005年   77897篇
  2004年   74476篇
  2003年   71796篇
  2002年   69465篇
  2001年   108834篇
  2000年   111547篇
  1999年   93582篇
  1998年   27027篇
  1997年   23693篇
  1996年   24071篇
  1995年   22727篇
  1994年   20905篇
  1993年   19724篇
  1992年   72048篇
  1991年   70107篇
  1990年   68438篇
  1989年   65721篇
  1988年   60337篇
  1987年   59165篇
  1986年   55267篇
  1985年   53049篇
  1984年   39342篇
  1983年   33424篇
  1982年   19879篇
  1979年   35885篇
  1978年   25663篇
  1977年   21248篇
  1976年   20342篇
  1975年   21826篇
  1974年   26157篇
  1973年   24810篇
  1972年   23211篇
  1971年   22043篇
  1970年   20261篇
  1969年   19331篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
111.
112.
113.
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   
114.
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   
115.
116.
117.
118.
119.
120.
Background A high Mandard score implies a non-response to chemotherapy in oesophageal adenocarcinoma. However, some patients exhibit tumour volume reduction and a nodal response despite a high score. This study examines survival and recurrence patterns in these patients.Methods Clinicopathological factors were analysed using multivariable Cox regression assessing time to death and recurrence. Computed tomography-estimated tumour volume change was examined in a subgroup of consecutive patients.Results Five hundred and fifty-five patients were included. Median survival was 55 months (Mandard 1–3) and 21 months (Mandard 4 and 5). In the Mandard 4 and 5 group (332 patients), comparison between complete nodal responders and persistent nodal disease showed improved survival (90 vs 18 months), recurrence rates (locoregional 14.75 vs 28.74%, systemic 24.59 vs 48.42%) and circumferential resection margin positivity (22.95 vs 68.11%). Complete nodal response independently predicted improved survival (hazard ratio 0.34 (0.16–0.74). Post-chemotherapy tumour volume reduction was greater in patients with a complete nodal response (−16.3 vs −7.7 cm3, p = 0.033) with no significant difference between Mandard groups.Conclusion Patients with a complete nodal response to chemotherapy have significantly improved outcomes despite a poor Mandard score. High Mandard score does not correspond with a non-response to chemotherapy in all cases and patients with nodal downstaging may still benefit from adjuvant chemotherapy.Subject terms: Oesophageal cancer, Surgical oncology  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