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   1607篇
  免费   177篇
  国内免费   2篇
耳鼻咽喉   2篇
儿科学   52篇
妇产科学   29篇
基础医学   233篇
口腔科学   40篇
临床医学   141篇
内科学   354篇
皮肤病学   17篇
神经病学   94篇
特种医学   58篇
外科学   266篇
综合类   47篇
预防医学   111篇
眼科学   4篇
药学   229篇
肿瘤学   109篇
  2022年   15篇
  2021年   26篇
  2020年   19篇
  2019年   25篇
  2018年   33篇
  2017年   34篇
  2016年   25篇
  2015年   33篇
  2014年   30篇
  2013年   44篇
  2012年   75篇
  2011年   63篇
  2010年   36篇
  2009年   27篇
  2008年   52篇
  2007年   58篇
  2006年   65篇
  2005年   62篇
  2004年   53篇
  2003年   55篇
  2002年   62篇
  2001年   49篇
  2000年   65篇
  1999年   60篇
  1998年   14篇
  1997年   23篇
  1996年   16篇
  1994年   15篇
  1993年   14篇
  1992年   44篇
  1991年   41篇
  1990年   41篇
  1989年   36篇
  1988年   29篇
  1987年   27篇
  1986年   42篇
  1985年   31篇
  1984年   24篇
  1983年   21篇
  1982年   14篇
  1981年   21篇
  1980年   15篇
  1979年   17篇
  1978年   28篇
  1976年   21篇
  1974年   21篇
  1972年   17篇
  1971年   15篇
  1970年   14篇
  1966年   14篇
排序方式: 共有1786条查询结果,搜索用时 0 毫秒
51.
Treatment of reflux oesophagitis with trimoprostil   总被引:2,自引:0,他引:2  
Forty-four patients with symptomatic endoscopically proven mild to moderate reflux oesophagitis were enrolled in a single-centre, double-blind, clinical trial comparing trimoprostil 750 micrograms taken 4 times daily with placebo. Patients treated with trimoprostil but not placebo experienced a significant reduction in the frequency (p less than 0.005) and duration (p less than 0.02) of heartburn. Both groups reported a reduction in the severity of heartburn and resulting sleep disturbance during the trial, but differences between them in these respects at the end of the trial did not reach statistical significance. There was a significant reduction in the severity of oesophagitis seen at endoscopy after treatment with trimoprostil (p less than 0.01) but not placebo. Trimoprostil was well tolerated and appears to be more effective than placebo in the treatment of mild to moderate symptomatic reflux oesophagitis. Although this agent's mode of action was not investigated, we speculate that it may be protective to human squamous oesophageal mucosa.  相似文献   
52.
Hereditary pancreatic endocrine tumours.   总被引:2,自引:0,他引:2  
The two main types of hereditary pancreatic neuroendocrine tumours are found in multiple endocrine neoplasia type 1 (MEN-1) and von Hippel-Lindau disease (VHL), but also in the rarer disorders of neurofibromatosis type 1 and tuberous sclerosis. This review considers the major advances that have been made in genetic diagnosis, tumour localization, medical and surgical treatment and palliation with systemic chemotherapy and radionuclides. With the exception of the insulinoma syndrome, all of the various hormone excess syndromes of MEN-1 can be treated medically. The role of surgery however remains controversial ranging from no intervention (except enucleation for insulinoma), intervening for tumours diagnosed only by biochemical criteria, intervening in those tumours only detected radiologically (1-2 cm in diameter) or intervening only if the tumour diameter is > 3 cm in diameter. The extent of surgery is also controversial, although radical lymphadenectomy is generally recommended. Pancreatic tumours associated with VHL are usually non-functioning and tumours of at least 2 cm in diameter should be resected. Practice guidelines recommend that screening in patients with MEN-1 should commence at the age of 5 years for insulinoma and at the age of 20 years for other pancreatic neuroendocrine tumours and variously at 10-20 years of age for pancreatic tumours in patients with VHL. The evidence is increasing that the life span of patients may be significantly improved with surgical intervention, mandating the widespread use of tumour surveillance and multidisciplinary team management.  相似文献   
53.
Balancing the generation of immune responses capable of controlling virus replication with those causing immunopathology is critical for the survival of the host and resolution of influenza‐induced inflammation. Based on the capacity of interleukin‐6 (IL‐6) to govern both optimal T‐cell responses and inflammatory resolution, we hypothesised that IL‐6 plays an important role in maintaining this balance. Comparison of innate and adaptive immune responses in influenza‐infected wild‐type control and IL‐6‐deficient mice revealed striking differences in virus clearance, lung immunopathology and generation of heterosubtypic immunity. Mice lacking IL?6 displayed a profound defect in their ability to mount an anti‐viral T‐cell response. Failure to adequately control virus was further associated with an enhanced infiltration of inflammatory monocytes into the lung and an elevated production of the pro‐inflammatory cytokines, IFN‐α and TNF‐α. These events were associated with severe lung damage, characterised by profound vascular leakage and death. Our data highlight an essential role for IL‐6 in orchestrating anti‐viral immunity through an ability to limit inflammation, promote protective adaptive immune responses and prevent fatal immunopathology.  相似文献   
54.
55.
HLA‐DRB1*0401 expression in humans has been associated with a predisposition to developing rheumatoid arthritis (RA) and collagen‐induced arthritis (CIA), while HLA‐DRB1*0402 is not associated with susceptibility. Here, we determined if mice transgenic (Tg) for human *0401 have a CD4+ T‐cell repertoire that predetermines proinflammatory cytokine production. The data show that both *0401 and *0402 Tg mice can produce TH1/TH17 cytokines, although the kinetics of response may be different. However, in the context of antigen‐specific responses in a CIA model, *0402 Tg mice generate a TH2 response that may explain their resistance to developing arthritis. In addition, a significant subset of naïve CD4+ T cells from *0402 Tg mice can be activated in polarizing conditions to differentiate into Treg cells that produce IFN‐γ. *0401 Tg mice harbor memory CD4+ T cells that differentiate into IL‐17+ cells in various polarizing conditions. Our data suggest that *0401 Tg mice generate a strong immune response to lipopolysaccharide and may be efficient in clearing infection, and may *0401 have been evolutionarily selected for this ability. Autoimmunity, such as RA, could likely be a bystander effect of the cytokine storm that, along with the presence of low Treg‐cell numbers in *0401 Tg mice, causes immune dysregulation.  相似文献   
56.
GABA(B) receptors mediate slow inhibitory neurotransmission in the brain and feature during excitatory synaptic plasticity, as well as various neurological conditions. These receptors are obligate heterodimers composed of GABA(B)R1 and R2 subunits. The two predominant R1 isoforms differ by the presence of two complement control protein modules or Sushi domains (SDs) in the N terminus of R1a. By using live imaging, with an α-bungarotoxin-binding site (BBS) and fluorophore-linked bungarotoxin, we studied how R2 stabilizes R1b subunits at the cell surface. Heterodimerization with R2 reduced the rate of internalization of R1b, compared with R1b homomers. However, R1aR2 heteromers exhibited increased cell surface stability compared with R1bR2 receptors in hippocampal neurons, suggesting that for receptors containing the R1a subunit, the SDs play an additional role in the surface stability of GABA(B) receptors. Both SDs were necessary to increase the stability of R1aR2 because single deletions caused the receptors to be internalized at the same rate and extent as R1bR2 receptors. Consistent with these findings, a chimera formed from the metabotropic glutamate receptor (mGluR)2 and the SDs from R1a increased the surface stability of mGluR2. These results suggest a role for SDs in stabilizing cell surface receptors that could impart different pre- and postsynaptic trafficking itineraries on GABA(B) receptors, thereby contributing to their physiological and pathological roles.  相似文献   
57.
T follicular helper (Tfh) cells are critical for providing the necessary signals to induce differentiation of B cells into memory and Ab-secreting cells. Accordingly, it is important to identify the molecular requirements for Tfh cell development and function. We previously found that IL-12 mediates the differentiation of human CD4(+) T cells to the Tfh lineage, because IL-12 induces naive human CD4(+) T cells to acquire expression of IL-21, BCL6, ICOS, and CXCR5, which typify Tfh cells. We have now examined CD4(+) T cells from patients deficient in IL-12Rβ1, TYK2, STAT1, and STAT3 to further explore the pathways involved in human Tfh cell differentiation. Although STAT1 was dispensable, mutations in IL12RB1, TYK2, or STAT3 compromised IL-12-induced expression of IL-21 by human CD4(+) T cells. Defective expression of IL-21 by STAT3-deficient CD4(+) T cells resulted in diminished B-cell helper activity in vitro. Importantly, mutations in STAT3, but not IL12RB1 or TYK2, also reduced Tfh cell generation in vivo, evidenced by decreased circulating CD4(+)CXCR5(+) T cells. These results highlight the nonredundant role of STAT3 in human Tfh cell differentiation and suggest that defective Tfh cell development and/or function contributes to the humoral defects observed in STAT3-deficient patients.  相似文献   
58.
59.
60.
Abstract

Enhancing treatment outcomes for clients who are predicted to deteriorate before leaving treatment has important implications for quality of client care. The effects of three interventions aimed at reducing client deterioration were examined in a sample of 1,374 clients whose outcome was contrasted across experimental groups and with a no-feedback/archival control group consisting of data from 1,445 clients. Results indicated that feedback to therapists reduced deterioration rates and improved outcome across clients, especially those predicted to be treatment failures. Therapist feedback effects were enhanced by the use of prompts to action based on a clinical support tools manual but not by the provision of direct feedback to clients.  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