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   279篇
  免费   18篇
  国内免费   2篇
耳鼻咽喉   1篇
儿科学   15篇
妇产科学   4篇
基础医学   29篇
口腔科学   9篇
临床医学   21篇
内科学   66篇
皮肤病学   14篇
神经病学   1篇
特种医学   64篇
外科学   17篇
综合类   24篇
预防医学   14篇
眼科学   1篇
药学   8篇
肿瘤学   11篇
  2023年   1篇
  2022年   1篇
  2020年   2篇
  2019年   2篇
  2018年   6篇
  2017年   4篇
  2016年   5篇
  2015年   2篇
  2014年   7篇
  2013年   9篇
  2012年   7篇
  2011年   7篇
  2010年   9篇
  2009年   12篇
  2008年   12篇
  2007年   9篇
  2006年   7篇
  2005年   8篇
  2004年   7篇
  2003年   4篇
  2002年   5篇
  2001年   2篇
  1999年   5篇
  1998年   17篇
  1997年   23篇
  1996年   15篇
  1995年   11篇
  1994年   5篇
  1993年   8篇
  1992年   2篇
  1990年   2篇
  1989年   6篇
  1988年   6篇
  1987年   6篇
  1986年   6篇
  1985年   19篇
  1984年   8篇
  1983年   3篇
  1982年   6篇
  1981年   7篇
  1980年   5篇
  1979年   1篇
  1978年   3篇
  1977年   2篇
  1976年   2篇
  1975年   2篇
  1949年   1篇
排序方式: 共有299条查询结果,搜索用时 15 毫秒
71.
Human T cell leukemia virus type II (HTLV-II) has been isolated from a patient (Mo) with features of leukemic reticuloendotheliosis (LRE) and from a patient with acquired immunodeficiency syndrome (AIDS). We have obtained another isolate of HTLV-II from a patient (CM) with severe hemophilia A, pancytopenia, and a 14-year history of staphylococcal and candidal infections but no evidence of T cell leukemia/lymphoma, AIDS, or LRE. Fresh mononuclear cells and cultured lymphocytes from CM express retroviral antigens indistinguishable by molecular criteria from HTLV-IIMo. Leukocyte cultures from CM yield hyperdiploid (48,XY, +2, +19) continuous lymphoid lines; human fetal cord blood lymphocytes (CBL) are transformed by cocultivation with these CM cell cultures but retain normal cytogenetic constitution. Electron microscopic examination of the CM cultures and transformed CBL reveals budding of extracellular viral particles, intracellular tubuloreticular structures, and viral particles contained within intracellular vesicles. CM cell cultures and the transformed CBL do not require exogenous interleukin 2, have T cell cytochemical features and mature T helper phenotypes, and exhibit minimal T helper and profound T suppressor activity on pokeweed mitogen-stimulated differentiation of normal B cells. These characteristics, which are similar to those observed with the first HTLV-II isolate, may represent properties of all HTLV-II-infected T cells.  相似文献   
72.
73.
74.
A multidetector computed tomography (MDCT) was installed in our department. Referral rates, examination protocols and detection rates of abnormal findings in CT examinations for cervical spine trauma 6 months before and 6 months after MDCT installation were compared to look for changes in practice. Retrospective analysis of all CT cervical spine examinations in patients with multiple trauma over two contiguous 6-month periods: from July 2003 to December 2003 (helical CT) and from January 2004 to June 2004 (MDCT). Variables recorded were number of CT examinations performed, scan plane coverage and traumatic abnormalities detected. Phantom dosimetry measurements for cervical spine examination in both helical CT and MDCT were compared. One hundred and fifty four patients underwent cervical spine CT during these periods. Helical CT period: of 91 patients undergoing CT cervical spine examination for trauma, 65 (71%) were complete cervical examinations and 26 (29%) were level-specific examinations. Eight patients (9%) had cervical spine fracture, six of which were apparent on radiographs. Dose estimations for thyroid, lens and breast were 24.76, 1.86 and 0.21 mGy, respectively, for complete cervical spine examinations. MDCT period: of 63 patients who underwent CT cervical spine examination for trauma, 61 (97%) were complete examinations and 2 (3%) were level-specific examinations. Six patients (11%) had cervical spine fracture, three of which were apparent on radiographs. Dose estimations for thyroid, lens and breast were 75.8, 9.7 and 0.7 mGy, respectively, for complete cervical spine examinations, which were notably higher than those for helical CT. After installation of MDCT, clinical requests for complete examination of the cervical spine following trauma increased. This changing trend resulted in a significantly higher radiation dose to thyroid, lens and breast.  相似文献   
75.
Interleukin-21 is a growth and survival factor for human myeloma cells   总被引:20,自引:3,他引:17       下载免费PDF全文
Brenne AT  Ro TB  Waage A  Sundan A  Borset M  Hjorth-Hansen H 《Blood》2002,99(10):3756-3762
Interleukin-21 (IL-21) is a recently cloned cytokine with homology to IL-2, IL-4, and IL-15. In this study we examined the effects of IL-21 on human myeloma cells. We found that IL-21 induced proliferation and inhibited apoptosis of the IL-6-dependent human myeloma cell lines ANBL-6, IH-1, and OH-2. The potency of IL-21 was close to that of IL-6 in the OH-2 cell line. Neutralizing antibodies to IL-6 or the IL-6 receptor transducer chain (gp130) did not affect IL-21-induced DNA synthesis, indicating that IL-21-induced proliferation was not mediated through these proteins. Tumor necrosis factor (TNF), another stimulator of myeloma cell growth, up-regulated the expression level of IL-21 receptor (IL-21R), and combinations of TNF and IL-21 gave synergistic effects on myeloma cell proliferation. Furthermore, 4 of 9 purified samples of primary myeloma cells showed a significant increase in DNA synthesis on stimulation of the cells by IL-21. By Western blot analysis, we demonstrated that the intracellular signaling pathways of IL-21 in myeloma cells involved phosphorylation of Jak1, Stat3, and Erk1/2 (p44/42 mitogen-activated protein kinase). IL-21 is a novel growth and survival factor in multiple myeloma and may represent a target for future therapy.  相似文献   
76.
77.

Background

Stopping antipsychotic treatment can interrupt improvement and exacerbate the illness. The reasons for discontinuing treatment during controlled clinical trials were analyzed to explore this phenomenon.

Methods

A post-hoc, pooled analysis was made of 4 randomized, double-blind clinical trials, 24–28 weeks in duration, involving 1627 patients with schizophrenia or a related disorder. Analyses combined all the atypical antipsychotic treatment groups in the studies.

Results

The majority of patients (53%) stopped their treatment at an early stage. Poor psychiatric response along with worsening symptoms was the most frequently given reason for discontinuing the course (36%), which was substantially more common than discontinuation due to poor tolerability of the medication (12%). This phenomenon was corroborated by less improvement in patients who discontinued treatment compared with those who completed, based on the PANSS total scores. Discontinuation due to poor response was, apparently, more predominantly linked to patient perception than to physicians' conclusions alone (80% vs. 20%). Discontinuation due to patient perception of poor response appeared to occur particularly early in the course of treatment. Patients who discontinued due to poor toleration of the medication responded in a more comparable manner with completers.

Conclusion

Discontinuing treatment may lead to exacerbation of symptoms, undermining therapeutic progress. In these studies, poor response to treatment and worsening of underlying psychiatric symptoms, and to a lesser extent, intolerability to medication were the primary contributors to treatment being discontinued. Our findings suggest that adherence may be enhanced by effective symptom control, as objectively measured and as subjectively perceived. Such strategies may improve patients' willingness to undertake long-term therapy and increase the likelihood of a better prognosis.  相似文献   
78.
79.
FMRP is associated to the ribosomes via RNA   总被引:8,自引:8,他引:8  
  相似文献   
80.
In order to search for new compounds with higher anti-cancer activities and lower toxicities, 19 amino acid derivatives of norcantharidin, of which 16 are unknown compounds, were designed and synthesized. Preliminary screening results revealed that 2-(syn-exo-7-oxabicyclo [2. 2. 1] heptane-2, 3-dicarboxylic imido)-N-phenyl glutaramic acid exhibited a fairly apparent inhibitory activity against human-hepatoma cells in vitro (inhibitory rate 39.4% at 0.025 μtmol/ml).  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