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   901篇
  免费   81篇
  国内免费   22篇
耳鼻咽喉   2篇
儿科学   50篇
妇产科学   14篇
基础医学   104篇
口腔科学   11篇
临床医学   94篇
内科学   171篇
皮肤病学   8篇
神经病学   52篇
特种医学   180篇
外科学   66篇
综合类   27篇
预防医学   57篇
眼科学   50篇
药学   70篇
中国医学   1篇
肿瘤学   47篇
  2020年   7篇
  2018年   6篇
  2017年   9篇
  2016年   8篇
  2015年   12篇
  2014年   24篇
  2013年   28篇
  2012年   16篇
  2011年   19篇
  2010年   23篇
  2009年   18篇
  2008年   18篇
  2007年   33篇
  2006年   23篇
  2005年   28篇
  2004年   24篇
  2003年   17篇
  2002年   9篇
  2001年   16篇
  2000年   17篇
  1999年   25篇
  1998年   40篇
  1997年   39篇
  1996年   41篇
  1995年   25篇
  1994年   22篇
  1993年   35篇
  1992年   24篇
  1991年   16篇
  1990年   31篇
  1989年   35篇
  1988年   36篇
  1987年   28篇
  1986年   22篇
  1985年   32篇
  1984年   13篇
  1983年   18篇
  1982年   25篇
  1981年   13篇
  1980年   11篇
  1979年   9篇
  1978年   7篇
  1977年   13篇
  1976年   22篇
  1975年   9篇
  1974年   5篇
  1973年   5篇
  1969年   4篇
  1968年   8篇
  1966年   9篇
排序方式: 共有1004条查询结果,搜索用时 15 毫秒
31.
32.
Transitional housing programs aim to improve living skills and housing stability for tenuously housed patients with mental illness. 113 consecutive Transitional Housing Team (THT) patients were matched to 139 controls on diagnosis, time of presentation, gender and prior psychiatric hospitalisation and compared using a difference-in-difference analysis for illness acuity and service use outcomes measured 1 year before and after THT entry/exit. There was a statistically significant difference-in-difference favouring THT participants for bed days (mean difference in difference ?20.76 days, SE 9.59, p = 0.031) and living conditions (HoNOS Q11 mean difference in difference ?0.93, SE 0.23, p < 0.001). THT cost less per participant (I$14,024) than the bed-days averted (I$17,348). The findings of reductions in bed days and improved living conditions suggest that transitional housing programs can have a significant positive impact for tenuously housed patients with high inpatient service usage, as well as saving costs for mental health services.  相似文献   
33.
34.
35.
Crucial to the interpretation of the results of any finite element analysis of a skeletal system is a test of the validity of the results and an assessment of the sensitivity of the model parameters. We have therefore developed finite element models of two crania of Macaca fascicularis and investigated their sensitivity to variations in bone material properties, the zygomatico-temporal suture and the loading regimen applied to the zygomatic arch. Maximum principal strains were validated against data derived from ex vivo strain gauge experiments using non-physiological loads applied to the macaque zygomatic arch. Elastic properties of the zygomatic arch bone and the zygomatico-temporal suture obtained by nanoindentation resulted in a high degree of congruence between experimental and simulated strains. The findings also indicated that the presence of a zygomatico-temporal suture in the model produced strains more similar to experimental values than a completely separated or fused arch. Strains were distinctly higher when the load was applied through the modelled superficial masseter compared with loading an array of nodes on the arch. This study demonstrates the importance of the accurate selection of the material properties involved in predicting strains in a finite element model. Furthermore, our findings strongly highlight the influence of the presence of craniofacial sutures on strains experienced in the face. This has implications when investigating craniofacial growth and masticatory function but should generally be taken into account in functional analyses of the craniofacial system of both extant and extinct species.  相似文献   
36.
Expression of TCRbeta and pre-TCR signalling are essential for differentiation of CD4- CD8- double negative (DN) thymocytes to the CD4+ CD8+ double-positive (DP) stage. Thymocyte development in adult Rag1, Rag2 or TCRbetadelta-deficient mice is arrested at the DN3 stage leading to the assumption that pre-TCR signalling and beta-selection occur at, and are obligatory for, the transition from DN3 to DN4. We show that the majority of DN3 and DN4 cells that differentiate during early embryogenesis in wild-type mice do not express intracellular (ic) TCRbeta/gammadelta. These foetal icTCRbeta-/gammadelta- DN4 cells were T lineage as determined by expression of Thy1 and icCD3 and TCRbeta DJ rearrangement. In addition, in the foetal Rag1-/- thymus, a normal percentage of DN4 cells were present. In wild-type mice after hydrocortisone-induced synchronisation of differentiation, the majority of DN4 cells that first emerged did not express icTCRbeta/gammadelta, showing that adult thymocytes can also differentiate to the DN4 stage independently of pre-TCR signalling. Pre-TCR signalling induced expansion in the DN4 population, but lack of TCRbeta/gammadelta expression did not immediately induce apoptosis. Our data demonstrate in vivo differentiation from DN3 to DN4 cell in the absence of TCRbeta/gammadelta expression in the foetal thymus, and after hydrocortisone treatment of adult mice.  相似文献   
37.
38.
39.
We recently identified DEPDC5 as the gene for familial focal epilepsy with variable foci and found mutations in >10% of small families with nonlesional focal epilepsy. Here we show that DEPDC5 mutations are associated with both lesional and nonlesional epilepsies, even within the same family. DEPDC5‐associated malformations include bottom‐of‐the‐sulcus dysplasia (3 members from 2 families), and focal band heterotopia (1 individual). DEPDC5 negatively regulates the mammalian target of rapamycin (mTOR) pathway, which plays a key role in cell growth. The clinicoradiological phenotypes associated with DEPDC5 mutations share features with the archetypal mTORopathy, tuberous sclerosis, raising the possibility of therapies targeted to this pathway. Ann Neurol 2014;75:782–787  相似文献   
40.
The complexity of the Plasmodium parasite and its life cycle poses a challenge to our understanding of the host immune response against malaria. Studying human immune responses during natural and experimental Plasmodium infections can enhance our understanding of malaria-protective immunity and inform the design of disease-modifying adjunctive therapies and next-generation malaria vaccines. Systems immunology can complement conventional approaches to facilitate our understanding of the complex immune response to the highly dynamic malaria parasite. In this review, recent studies that used systems-based approaches to evaluate human immune responses during natural and experimental Plasmodium falciparum and Plasmodium vivax infections as well as during immunization with candidate malaria vaccines are summarized and related to each other. The potential for next-generation technologies to address the current limitations of systems-based studies of human malaria are discussed.  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