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   4413篇
  免费   300篇
  国内免费   14篇
耳鼻咽喉   23篇
儿科学   98篇
妇产科学   53篇
基础医学   756篇
口腔科学   79篇
临床医学   427篇
内科学   762篇
皮肤病学   85篇
神经病学   782篇
特种医学   201篇
外科学   394篇
综合类   9篇
一般理论   3篇
预防医学   309篇
眼科学   54篇
药学   297篇
中国医学   6篇
肿瘤学   389篇
  2024年   8篇
  2023年   55篇
  2022年   93篇
  2021年   161篇
  2020年   111篇
  2019年   157篇
  2018年   149篇
  2017年   126篇
  2016年   152篇
  2015年   176篇
  2014年   222篇
  2013年   234篇
  2012年   421篇
  2011年   402篇
  2010年   229篇
  2009年   221篇
  2008年   326篇
  2007年   317篇
  2006年   288篇
  2005年   230篇
  2004年   205篇
  2003年   186篇
  2002年   137篇
  2001年   19篇
  2000年   17篇
  1999年   19篇
  1998年   23篇
  1997年   9篇
  1996年   12篇
  1995年   9篇
  1994年   5篇
  1993年   4篇
  1990年   1篇
  1989年   1篇
  1981年   1篇
  1975年   1篇
排序方式: 共有4727条查询结果,搜索用时 31 毫秒
61.
The impact of paternal care on the development of catecholaminergic fiber innervations in the prefrontal cortex, nucleus accumbens, hippocampus and the amygdala was quantitatively investigated in the biparental Octodon degus. Two age (juvenile, adult) and rearing groups: (1) degus reared without father and (2) degus raised by both parents were compared. Juvenile father-deprived animals showed significantly elevated densities of TH-immunoreactive fibers in all analyzed regions, except in the orbitofrontal cortex, as compared to biparentally reared animals. This difference between the two rearing groups was still evident in adulthood in the prelimbic and infralimbic cortices and in the hippocampal formation. Interestingly, the elevated TH fiber density in both nucleus accumbens subregions was reversed in adulthood, i.e. adult father-deprived animals showed strongly reduced TH fiber densities as compared to biparentally reared animals. We show here that paternal care plays a critical role in the functional maturation of catecholaminergic innervation patterns in prefrontal and limbic brain circuits.  相似文献   
62.
Speech adaptation after oral rehabilitation is based on a complex interaction of articulatory and myofunctional factors. The knowledge of basic phonetic principles may help clinicians identify phonetic problems associated with prosthodontic treatment. The purpose of this article is to illustrate basic phonetic terminology, standard Chinese (Putonghua) phonetics, and the anatomic structures relevant for dentistry. In cooperation with a Chinese linguistic specialist, Chinese articulators were selected and are described and compared with English phonetics. Established test words and sentences aid the identification of mispronounced articulators and their related dental structures. The pronunciation of most consonants and vowels in standard Chinese is similar to English, but some of them, such as the retropalatals (/zh/ [t?], /ch/ [th?], /sh/ [?]), have notable differences. Palatal consonants (/j/ [t?], /q/ [t?h], /x/ [?]) are unique to the Chinese phonetic system and are not found in English phonetics. The comprehension of the basic anatomic regions involved in Chinese phonetics may help prosthodontists treat patients whose native language is standard Chinese.  相似文献   
63.
Treatment of relapsed or refractory multiple myeloma remains a challenge and novel treatment regimen are required. Here, a matched pair analysis was performed comparing TCID (thalidomide, cyclophosphamide, idarubicin, dexamethasone) treatment to the treatment of patients with VID (vincristine, idarubicin, dexamethasone) or with VRID (vinorelbine, idarubicin, dexamethasone) for relapsed or refractory multiple myeloma. In total, 197 patients were enrolled in multicenter trials. After matching for important prognostic variables 46 matched-pairs (total of 138 patients) could be analysed with regard to survival, toxicity and efficacy. Interestingly, a significant improvement of overall response rate (ORR) for TCID treatment compared to VID and VRID was found. In addition, TCID treatment also led to a significantly higher overall survival (OS) as well as progression-free survival (PFS) compared to VID and VRID. In conclusion, TCID treatment appears to be superior to VRID and VID treatment in patients with progressive or refractory myeloma.  相似文献   
64.
NK cell function is important in the immune response to HIV infection. NKG2C and NKG2A are activating and inhibitory NK cell receptors, respectively, and their only known ligand, HLA-E, demonstrates increased expression in HIV infection and presents at least one HIV-derived peptide. A variation in chromosome 12 exists in which the 16-kb section of DNA encompassing the nkg2c gene is completely absent. DNA samples of 433 HIV-1-infected patients and 280 controls were genotyped by PCR, and revealed an association of the absence variation with a higher risk of HIV infection, as well as faster progression and higher pretreatment viral loads (p<0.05, respectively). Surface NKG2C expression, analyzed by FACS, on the freshly isolated lymphocytes of 20 control and 19 HIV-infected donors revealed that NKG2C expression is genotype dependent in both populations: no NKG2C expression in the -/- groups, intermediate expression in the +/- groups, and highest expression in the +/+ groups. The comparison of NKG2C and NKG2A expression in HIV and control groups (+/- and +/+ included) indicates an increased NKG2C expression on HIV patient NK cells (p<0.05) and decreased inhibitory NKG2A expression on CD8 T cells (p<0.001), and both these effects are more striking in the +/+ genotype (p<0.005). Furthermore, a positive correlation was found between HIV viral load and the proportion of NKG2C(+) NK cells. The increased expression of NKG2C in HIV patients, in combination with the genetic association of the absence variation with an increased susceptibility to HIV infection, higher HIV viral set point, and a faster progression, indicate that NKG2C is important in the defense against HIV infection and progression.  相似文献   
65.
66.
67.
68.
69.
70.
One promising approach for the induction of transplant tolerance is the pre-treatment of transplant recipients with donor MHC-alloantigen. Our study focuses on the oral delivery of MHC-antigen encoding genes via chitosan-DNA nanoparticles to modulate the alloimmune response in order to reduce the development of transplant arteriosclerosis, the hallmark feature of chronic rejection after heart transplantation. Therefore, we performed fully allogeneic mouse abdominal aortic transplants using C57BL/6 (H2b) mice as donors and CBA.J (H2k) mice as recipients. Aortic grafts were analyzed by histology and morphometry on day 30 after transplantation, levels of circulating alloantibodies were detected by FACS analysis. Pre-treatment of recipient mice with chitosan-DNA nanoparticles encoding for Kb, one of the MHC-I molecules of the donor, resulted in a significant reduction of intimal proliferation compared to untreated controls. When Ovalbumin was fed instead of Kb encoding nanoparticles (Kb-NP) or Balb/c (H2d) grafts were used instead of C57BL/6 (H2b) grafts as antigen controls, both groups showed no reduction of intimal thickness indicating an antigen-specific mechanism. In addition, analysis of peripheral blood of the transplanted mice showed significant suppression of alloantibody formation in the Kb-NP fed group compared to all other allogeneic transplanted groups suggesting modulation of the humoral immune response. These results demonstrate the potential of chitosan-DNA nanoparticles to induce Kb-specific tolerance and to reduce the development of transplant arteriosclerosis.  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