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   556篇
  免费   41篇
  国内免费   1篇
耳鼻咽喉   1篇
儿科学   72篇
妇产科学   7篇
基础医学   64篇
口腔科学   11篇
临床医学   80篇
内科学   129篇
皮肤病学   18篇
神经病学   34篇
特种医学   94篇
外科学   20篇
综合类   10篇
预防医学   17篇
眼科学   1篇
药学   24篇
中国医学   1篇
肿瘤学   15篇
  2023年   2篇
  2022年   4篇
  2020年   1篇
  2019年   5篇
  2018年   8篇
  2017年   11篇
  2016年   8篇
  2015年   17篇
  2014年   11篇
  2013年   28篇
  2012年   16篇
  2011年   14篇
  2010年   32篇
  2009年   19篇
  2008年   17篇
  2007年   8篇
  2006年   11篇
  2005年   10篇
  2004年   5篇
  2003年   4篇
  2002年   10篇
  2001年   9篇
  2000年   4篇
  1999年   9篇
  1998年   22篇
  1997年   33篇
  1996年   27篇
  1995年   31篇
  1994年   23篇
  1993年   37篇
  1992年   5篇
  1991年   7篇
  1990年   15篇
  1989年   16篇
  1988年   17篇
  1987年   11篇
  1986年   13篇
  1985年   13篇
  1984年   3篇
  1983年   4篇
  1982年   6篇
  1981年   14篇
  1980年   6篇
  1979年   2篇
  1978年   5篇
  1977年   7篇
  1976年   12篇
  1975年   4篇
  1968年   1篇
  1957年   1篇
排序方式: 共有598条查询结果,搜索用时 15 毫秒
531.
532.
Aim: To test the hypothesis that implementing guidelines for the standardized care of the extremely premature infant (<27 weeks) in the first week of life would improve patient outcomes in an all referral NICU. Methods: Data were collected on all infants <27 weeks gestational age and <7 days of age on admission cared for using these small baby guidelines (SBG), as well as on all age‐matched infants admitted the year prior (comparison). Results: Thirty‐seven patients were cared for utilizing the SBG and 40 patients were in the comparison group. There were no differences between the groups in gestational age, birthweight or age on admission. There was no difference in survival to discharge (73% SBG, 70% comparison). The mean length of stay for survivors was 112 ± 38 days SBG and 145 ± 76 days (p < 0.05) comparison group. Survival without BPD was greater in the SBG group (24%) than in the comparison group (9%; p < 0.05), and survival without severe IVH was greater in the SBG group (65%) than in the comparison group (38%; p < 0.01). Conclusions: These data demonstrate that applying a unified approach to the care of the extremely premature infant in the first week of life resulted in a decrease in the length of hospitalization and improved patient outcomes.  相似文献   
533.
Peterson EA and Petty EM. Conquering the complex world of human septins: implications for health and disease. Septins are highly conserved filamentous proteins first characterized in budding yeast and subsequently identified in must eukaryotes. Septins can bind and hydrolyze GTP, which is intrinsically related to their formation of septin hexamers and functional protein interactions. The human septin family is composed of 14 loci, SEPT1‐SEPT14, which encode dozens of different septin proteins. Their central GTPase and polybasic domain regions are highly conserved but they diverge in their N‐terminus and/or C‐terminus. The mechanism by which the different isoforms are generated is not yet well understood, but one can hypothesize that the use of different promoters and/or alternative splicing could give rise to these variants. Septins perform diverse cellular functions according to tissue expression and their interacting partners. Functions identified to date include cell division, chromosome segregation, protein scaffolding, cellular polarity, motility, membrane dynamics, vesicle trafficking, exocytosis, apoptosis, and DNA damage response. Their expression is tightly regulated to maintain proper filament assembly and normal cellular functions. Alterations of these proteins, by mutation or expression changes, have been associated with a variety of cancers and neurological diseases. The association of septins with cancer results from alterations of expression in solid tumors or translocations in leukemias [mixed lineage leukemia (MLL)]. Expression changes in septins have also been associated with neurological conditions such as Alzheimer's and Parkinson's disease, as well as retinopathies, hepatitis C, spermatogenesis and Listeria infection. Pathogenic mutations of SEPT9 were identified in the autosomal dominant neurological disorder hereditary neuralgic amyotrophy (HNA). Human septin research over the past decade has established their importance in cell biology and human disease. Further functional characterization of septins is crucial to our understanding of their possible diagnostic, prognostic, and therapeutic applications.  相似文献   
534.
535.
Aims: In this study the aim was to evaluate the effect of botulinum toxin A (BoNT‐A) treatment on muscle tone, contracture development and gait pattern in young children with cerebral palsy (CP). Method: Fifteen children with spastic CP (mean age = 16 months) were included in a randomized control study. All received a daily stretching programme and children in the BoNT‐A group additionally received two injections, 6 months apart in the gastrocnemius muscle. Outcomes were assessed at baseline, and after 1 and 3.5 years. A 3D gait‐analysis was performed at 5 years of age. Results: Plantarflexor muscle tone in the BoNT‐A group was significantly reduced after 3.5 years, while the muscle tone at the ankle and knee in the control group remained unchanged. The change‐score in knee‐flexion muscle tone between the groups was significantly different after 3.5 years. The knee joint ROM was significantly increased at 1 year in the BoNT‐A group but reduced at the knee and ankle joints in the control group after 3.5 years. No group differences were found for gait analysis, GMFM‐66 or PEDI. Conclusion: Early treatment of BoNT‐A in children with spastic CP may decrease muscle tone and decelerate contracture development after 3.5 years. The effect on gait development remains inconclusive.  相似文献   
536.
537.
BACKGROUND: Allergen challenge in allergic rhinitis patients leads to local eosinophilia and Th2-type cytokine expression. Natural exposure to grass pollen is additionally characterized by epithelial mast-cell infiltration. We hypothesized that perennial allergic rhinitis is also associated with T-cell and eosinophil infiltration of the nasal mucosa, local Th2-type cytokine expression, and increased numbers of nasal epithelial mast cells. METHODS: Nasal biopsies from perennial allergic rhinitis patients and controls were analysed by immunocytochemistry for different cell populations and in situ hybridization for cytokine mRNA-expressing cells. RESULTS: Perennial allergic rhinitis was associated with increased numbers of submucosal CD3+ T cells (P=0.05), EG2+ activated eosinophils (P=0.01), and CD68+ macrophages (P=0.01) compared to controls. Epithelial, but not submucosal, tryptase-positive mast cells were also elevated in rhinitics compared to controls (P=0.01). The numbers of cells expressing interleukin (IL)-5 were higher (P=0.01) and the numbers of cells expressing IL-2 were lower (P=0.04) in rhinitic patients than controls. There were no significant differences for either IL-4 or interferon-gamma between the groups. CONCLUSIONS: Perennial allergic rhinitis is characterized by mast-cell migration into the epithelium; submucosal infiltration by T cells, eosinophils, and macrophages; and an imbalance in local T-cell cytokine production in favour of enhanced IL-5 and reduced IL-2 expression.  相似文献   
538.
BACKGROUND: Although early trials indicate the treatment of restenosis with radiation therapy is safe and effective, the long-term impact of this new technology has been questioned. The possibility of late untoward consequences, such as aneurysm formation, perforation, and accelerated vascular disease, is of significant concern. Furthermore, it is not known whether the beneficial effects of radiation therapy will be durable or whether radiation will only delay restenosis. METHODS AND RESULTS: A double-blind, randomized trial was undertaken to compare 192Ir with placebo sources in patients with previous restenosis after coronary angioplasty. Patients were randomly assigned to receive a 0.76-mm (0. 03-in) ribbon containing sealed sources of either 192Ir or placebo. All patients underwent repeat coronary angiography at 6 months. All living patients were contacted 24 months after their index study procedure. Patients were assessed with respect to the need for target-lesion revascularization or nontarget-lesion revascularization, occurrence of myocardial infarction, or death. Over a 9-month period, 55 patients were enrolled; 26 were randomized to 192Ir and 29 to placebo. Follow-up was obtained in 100% of living patients at a minimum of 24 months. Target-lesion revascularization was significantly lower in the 192Ir group (15.4% versus 44.8%; P<0. 01). Nontarget-lesion revascularization was similar in 192Ir and placebo patients (19.2% versus 20.7%; P=NS). There were 2 deaths in each group. The composite end point of death, myocardial infarction, or target-lesion revascularization was significantly lower in 192Ir-treated versus placebo-treated patients (23.1% versus 51.7%; P=0.03). No patient in the 192Ir group sustained a target-lesion revascularization later than 10 months. CONCLUSIONS: At 2-year clinical follow-up, treatment with 192Ir demonstrates significant clinical benefit. Although further follow-up (including late angiography) will be necessary, no clinical events have occurred to date in the 192Ir group to suggest major untoward effects of vascular radiotherapy. At the intermediate follow-up time point, vascular radiotherapy continues to be a promising new treatment for restenosis.  相似文献   
539.
羟考酮对左旋氧氟沙星在人体内药物动力学的影响   总被引:1,自引:1,他引:0  
目的研究羟考酮对左旋氧氟沙星(LVFX)在人体内药物动力学的影响。方法8名健康志愿者,单用LVFX或合用羟考酮,用HPLC法测定血药浓度。结果单用LVFX500mg后的药物动力学参数分别为tmax(1.562±1.050)h,cmax(6.6419±0.15860)μg/ml,AUC(47.65±11.29)h*μg/ml,T1/2(β)(7.034±0.941)h;合用羟考酮时,LVFX的药物动力学参数分别为tmax(1.125±0.641)h,cmax(7.652±2.594)μg/ml,AUC(48.74±10.58)h*μg/ml,T1/2(β)(6.275±0.588)h。两者除T1/2ka和cmax外,无显著性差异。结论羟考酮对LVFX在人体内药物动力学参数无影响。  相似文献   
540.
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