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   192篇
  免费   16篇
  国内免费   1篇
耳鼻咽喉   1篇
儿科学   4篇
妇产科学   6篇
基础医学   25篇
口腔科学   2篇
临床医学   21篇
内科学   38篇
神经病学   11篇
特种医学   5篇
外科学   19篇
综合类   10篇
预防医学   17篇
眼科学   2篇
药学   25篇
肿瘤学   23篇
  2022年   3篇
  2021年   7篇
  2019年   6篇
  2018年   4篇
  2017年   4篇
  2016年   4篇
  2015年   6篇
  2014年   5篇
  2013年   9篇
  2012年   6篇
  2011年   10篇
  2010年   6篇
  2009年   4篇
  2008年   15篇
  2007年   13篇
  2006年   16篇
  2005年   20篇
  2004年   10篇
  2003年   13篇
  2002年   12篇
  2001年   6篇
  2000年   7篇
  1999年   2篇
  1997年   4篇
  1996年   1篇
  1995年   2篇
  1994年   1篇
  1991年   1篇
  1990年   1篇
  1988年   1篇
  1985年   1篇
  1984年   1篇
  1983年   2篇
  1980年   3篇
  1978年   1篇
  1974年   1篇
  1973年   1篇
排序方式: 共有209条查询结果,搜索用时 15 毫秒
61.
62.
PURPOSETo determine whether relative cortical thickness measurements of the precentral and postcentral gyri can be used to differentiate the central sulcus from adjacent cortical sulci.METHODSTurbo inversion-recovery MR imaging of the entire brain was done with scans parallel to the anterior commissure-posterior commissure line. Cortical thickness was measured in each hemisphere with a jeweler''s eyepiece with 0.1-mm gradations. Three measurements were obtained perpendicular to the central, precentral, and superior frontal sulci, as determined by means of established anatomic methods. The ratios of cortical thickness on both sides of the central, precentral, and superior frontal sulci were calculated and compared.RESULTSThe mean ratio of precentral/postcentral gyri was 1.64 for the right hemisphere and 1.53 for the left hemisphere. The mean cortical thickness ratios were as follows: 1.01 for the right hemisphere and 3.01 for the left hemisphere across the precentral sulcus, and 1.03 for the right hemisphere and 0.99 for the left hemisphere across the superior frontal sulcus.CONCLUSIONCortical thickness measurements across the central sulcus provide a method for locating the primary motor (precentral gyri) and primary somatosensory (postcentral gyri) cortices. The higher mean cortical thickness ratio across the central sulcus corresponds with known cytoarchitectonic relationships.  相似文献   
63.
64.
PURPOSE: Fatigue and depression typically occur together in cancer patients, suggesting a common etiology, perhaps based on serotonin. This randomized clinical trial tested whether paroxetine, a selective serotonin reuptake inhibitor antidepressant known to modulate brain serotonin, would reduce fatigue in cancer patients and whether any reduction was related to depression. PATIENTS AND METHODS: Cancer patients undergoing chemotherapy for the first time were assessed for fatigue. Of 704 patients who reported fatigue at their second chemotherapy cycle, 549 patients were randomly assigned to receive either 20 mg of oral paroxetine hydrochloride daily or placebo for 8 weeks. The assessments of fatigue and depression were performed at cycles 3 and 4 of chemotherapy. RESULTS: A total of 244 patients treated with paroxetine and 235 patients treated with placebo provided assessable data. No difference was detected in fatigue between patient groups. At the end of the study, there was a difference between groups in the mean level of depression (Center for Epidemiologic Studies Depression scores, 12.0 v 14.8, respectively; P <.01). CONCLUSION: Paroxetine had no influence on fatigue in patients receiving chemotherapy. A possible explanation is that cancer-related fatigue does not involve a reduction in brain 5-HT levels.  相似文献   
65.
66.
67.

Background

Pedicle-screw-rod fixation system is very popular surgical remedy for degenerative disc disease. It is important to observe load vs. spinal motion characteristic for better understanding of clinical problems and treatment of spinal instability associated with low-back pain.

Objective

The objective of this study is to understand the effect [range of motion (ROM) and intervertebral foramen height] of pedicle-screw fixation with three rod materials on lumbar spine under three physiological loading conditions.

Method

A three-dimensional finite element (FE) model of lumbar to sacrum (L1-S) vertebrae with pedicle-screw-rod fixation at L3-L5 level is developed. Three rod materials [titanium alloy (Ti6Al4V), ultra-high molecular weight poly ethylene (UHMWPE) and poly-ether-ether-ketone (PEEK)] are used for two-level fixation and the FE models are simulated for axial rotation, lateral bending and flexion-extension under ±10 Nm moment and 500 N compressive load and compared with the intact (natural) model.

Result & discussion

For axial rotation, lateral bending and flexion, ROM increased 2.8, 4.5 and 1.83 times respectively for UHMWPE, and 3.7, 7.2 and 2.15 times respectively for PEEK in comparison to Ti6Al4V. As ROM is 49, 29 and 31% of the intact model during axial rotation, lateral bending and flexion respectively, PEEK rod produced better motion flexibility than Ti6Al4V and UHMWPE rod. Foramen height increased insignificantly by 2.21% for the PEEK rod with respect to the intact spine during flexion. For the PEEK rod, maximum stress of 40 MPa during axial rotation is much below the yield stress of 98 MPa.

Conclusion

Ti6Al4V pedicle-screw-rod fixation system highly restricted the ROM of the spine, which is improved by using UHMWPE and PEEK, having lower stiffness. The foramen height did not vary significantly for any implant materials. In terms of ROM and maximum stress, PEEK rod may be considered for a better implant design to get better ROM and thus mobility.  相似文献   
68.
69.
Snake bite is an important health hazard in tropical countries and is associated with significant morbidity and mortality. Herpes labialis is a common ailment caused by the Herpes simplex virus. There is no published data showing any association between the snake bite and development of Herpes labialis. Here, we present a series of patients who developed Herpes labialis after Russell's viper bite and had acute kidney injury. We attempted to find whether snake bite is an immunosuppressed state and whether it could have pre-disposed the patients to the development of these lesions.  相似文献   
70.
Adoptive immunotherapy with tumor-specific T cells has emerged as a valid approach for prevention or treatment of diseases, such as melanoma and EBV-associated lymphoma. As interleukin (IL) 15 promotes survival of CD8(+) memory CTLs, we hypothesized that it could be used to enhance antitumor immunity in vivo through the maintenance of adoptively transferred memory CTL. To test this, we treated mice bearing P1A(+) tumors with adoptively transferred T cells possessing a transgenic Valpha8(+) T-cell receptor specific for the P1A tumor antigen (called P1CTL). Mice were then randomized to receive daily low-dose IL-15 (0.5 microg/day) or PBS. Mice receiving the transgenic P1CTL and IL-15 experienced a significantly delayed tumor relapse or complete tumor regression (P < 0.002 compared with PBS), with a striking persistence of the CD8(+) Valpha8(+) P1CTL compared with mice receiving the CD8(+) Valpha8(+) P1CTL and PBS vehicle (26.3 versus 5.1% P < 10(-5)). Animals exhibiting complete tumor regression had a significant population of CD8(+) Valpha8(+) P1CTL (46%) that persisted with IL-15 treatment until 140 days after adoptive transfer and successfully defended them against tumor rechallenge without IL-15. Low-dose IL-2 afforded no protection over vehicle and resulted in lower percentages of T cells with an activated memory phenotype, lower Bcl-2 expression, and lower ex vivo antitumor cytotoxicity compared with mice treated with IL-15. Collectively, the data support the notion that exogenous low-dose IL-15 therapy can enhance and even reverse the limited efficacy of adoptively transferred tumor-specific T-cell therapy and may do so in a fashion that is superior and distinct from exogenous IL-2 therapy.  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