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   563篇
  免费   28篇
  国内免费   5篇
耳鼻咽喉   6篇
儿科学   26篇
妇产科学   12篇
基础医学   47篇
口腔科学   7篇
临床医学   45篇
内科学   78篇
皮肤病学   11篇
神经病学   46篇
特种医学   82篇
外科学   81篇
综合类   42篇
预防医学   42篇
眼科学   6篇
药学   31篇
肿瘤学   34篇
  2021年   3篇
  2020年   5篇
  2019年   3篇
  2018年   11篇
  2017年   6篇
  2016年   3篇
  2015年   6篇
  2014年   8篇
  2013年   20篇
  2012年   6篇
  2011年   18篇
  2010年   25篇
  2009年   26篇
  2008年   10篇
  2007年   13篇
  2006年   28篇
  2005年   18篇
  2004年   44篇
  2003年   24篇
  2002年   15篇
  2001年   9篇
  2000年   9篇
  1999年   3篇
  1998年   26篇
  1997年   23篇
  1996年   23篇
  1995年   29篇
  1994年   16篇
  1993年   12篇
  1992年   5篇
  1991年   7篇
  1990年   10篇
  1989年   21篇
  1988年   15篇
  1987年   10篇
  1986年   10篇
  1985年   6篇
  1984年   13篇
  1983年   10篇
  1982年   12篇
  1981年   6篇
  1980年   7篇
  1979年   4篇
  1978年   7篇
  1977年   4篇
  1975年   2篇
  1974年   1篇
  1973年   1篇
  1972年   1篇
  1970年   1篇
排序方式: 共有596条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.

Objectives

The aim of the study was to determine whether behaviourally informed short message service (SMS) primer and reminder messages could increase the return rate of HIV self‐sampling kits ordered online.

Methods

The study was a 2 × 2 factorial design randomized control trial. A total of 9585 individuals who ordered a self‐sampling kit from www.freetesting.hiv different SMS combinations: 1) standard reminders sent days 3 and 7 after dispatch (control); 2) primer sent 1 day after dispatch plus standard reminders; 3) behavioural insights (BI) reminders (no primer); or 4) primer plus BI reminders. The analysis was restricted to individuals who received all messages (n = 8999). We used logistic regression to investigate independent effects of the primer and BI reminders and their interaction. We explored the impact of sociodemographic characteristics on kit return as a secondary analysis.

Results

Those who received the primer and BI reminders had a return rate 4% higher than that of those who received the standard messages. We found strong evidence of a positive effect of the BI reminders (odds ratio 1.13; 95% confidence interval 1.04–1.23; P = 0.003) but no evidence for an effect of the primer, or for an interaction between the two interventions. Odds of kit return increased with age, with those aged ≥ 65 years being almost 2.5 times more likely to return the kit than those aged 25–34 years. Men who have sex with men were 1.5–4.5 times more likely to return the kit compared with other sexual behaviour and gender identity groups. Non‐African black clients were 25% less likely to return the kit compared with other ethnicities.

Conclusions

Adding BI to reminder messages was successful in improving return rates at no additional cost.  相似文献   
5.
Glioblastoma muhiforme (GBM) is a highly invasive brain tumour that is unvaryingly fatal in humans clesplte even aggres- sive therapeutic approaches such as surgical resection followed by chemotherapy and radiotherapy. Unconventional treatment options such as gene therapy provide an intriguing option for curbing glioma related deaths. To date, gene therapy has yielded encouraging results in preclinical animal models as well as promising safety profiles in phase I clinical trials, but has failed to demonstrate significant therapeutic efficacy in phase III clinical trials. The most widely studied antiglioma gene therapy strategies are suicide gene therapy, genetic immuno- therapy and oncolytic virotherapy, and we have attributed the challenging transition of these modalities into the clinic to four major road- blocks : ( 1 ) anatomical features of the central nervous system, (2) the host immune system, (3) heterogeneity and invasiveness of GBM and (4) limitations in current GBM animal models. In this review, we discuss possible ways to jump these hurdles and develop new gene therapies that may be used alone or in synergy with other modalities to provide a powerful treatment option for patients with GBM.  相似文献   
6.
转录因子T-bet与哮喘大鼠气道炎症及川芎嗪的干预效应   总被引:1,自引:0,他引:1  
目的:转录因子T-bet在支气管哮喘的发病中起重要作用,川芎嗪治疗哮喘有效。实验拟观察川芎嗪对哮喘大鼠气道炎症的影响和转录因子T-bet的调控作用。方法:实验于2005-11/2006-06在南京医科大学完成。①实验材料及分组:72只SPF级SD大鼠随机分为正常对照组、哮喘模型组、川芎嗪小剂量组(20mg/kg)、川芎嗪中剂量组(40mg/kg)、川芎嗪大剂量组(80mg/kg)和地塞米松组,每组12只。实验用磷酸川芎嗪注射液为丽珠集团利民制药厂生产)。②实验过程及评估:以卵蛋白腹腔注射并雾化吸入制备大鼠哮喘模型,末次雾化后24h内麻醉后处死大鼠。观察6组大鼠肺组织形态学变化;测定支气管壁厚度、支气管平滑肌厚度、嗜酸粒细胞和淋巴细胞数。采用免疫组织化学半定量法测定肺组织T-bet蛋白的表达;进行转录因子T-bet蛋白表达量与气道炎症的相关性分析。实验过程中对动物处置符合动物伦理学标准。结果:①哮喘模型组嗜酸粒细胞、淋巴细胞、支气管壁厚度和支气管平滑肌厚度,明显高于正常对照组相应指标(P均<0.01);与哮喘模型组比较,川芎嗪小、中、大剂量组和地塞米松组上述4项指标均减少(P均<0.01)。②哮喘模型组、川芎嗪小、中、大剂量组和地塞米松组的T-bet表达量低于正常对照组(P均<0.01);与哮喘模型组比较,川芎嗪小、中、大剂量组T-bet表达量增加(P均<0.01);随着川芎嗪剂量增加,T-bet表达量亦相应增加,川芎嗪小、中、大剂量组之间两两比较,差异均有统计学意义(P均<0.01)。③相关分析显示哮喘模型组T-bet蛋白表达量与嗜酸性粒细胞和淋巴细胞浸润数呈负相关(r=-0.81,-0.85,P<0.01),与支气管管壁厚度和支气管平滑肌厚度呈负相关(r=-0.77,-0.79,P<0.01)。结论:支气管哮喘大鼠存在T-bet低表达;川芎嗪可抑制气道炎症,增加转录因子T-bet蛋白的表达,纠正Th1/Th2失衡,从而治疗支气管哮喘。  相似文献   
7.

Objective

To estimate the global cost of establishing and operating the educational and refractive care facilities required to provide care to all individuals who currently have vision impairment resulting from uncorrected refractive error (URE).

Methods

The global cost of correcting URE was estimated using data on the population, the prevalence of URE and the number of existing refractive care practitioners in individual countries, the cost of establishing and operating educational programmes for practitioners and the cost of establishing and operating refractive care facilities. The assumptions made ensured that costs were not underestimated and an upper limit to the costs was derived using the most expensive extreme for each assumption.

Findings

There were an estimated 158 million cases of distance vision impairment and 544 million cases of near vision impairment caused by URE worldwide in 2007. Approximately 47 000 additional full-time functional clinical refractionists and 18 000 ophthalmic dispensers would be required to provide refractive care services for these individuals. The global cost of educating the additional personnel and of establishing, maintaining and operating the refractive care facilities needed was estimated to be around 20 000 million United States dollars (US$) and the upper-limit cost was US$ 28 000 million. The estimated loss in global gross domestic product due to distance vision impairment caused by URE was US$ 202 000 million annually.

Conclusion

The cost of establishing and operating the educational and refractive care facilities required to deal with vision impairment resulting from URE was a small proportion of the global loss in productivity associated with that vision impairment.  相似文献   
8.
9.
A bleeding disorder with absent collagen-induced platelet aggregation and adhesion has been described in a patient whose platelets failed to express surface glycoprotein Ia. We studied the interaction of her platelets with subendothelium in an annular perfusion chamber and the interaction with purified human collagen type III in a rectangular perfusion system under flow conditions. Platelet adherence was almost completely absent both at low and high shear rates. The few platelets which adhered remained in the contact stage without subsequent spreading and aggregate formation. Addition of a monoclonal antibody, which was directed against the von Willebrand moiety of FVIII-VWF, to the blood, completely abolished platelet adherence at high shear rates and had a partial effect at low shear rates. These data indicate that von Willebrand factor plays a role in the initial attachment (contact stage) of platelets to subendothelium. We conclude that the bleeding disorder and excessively prolonged bleeding time in our patient are caused by a new specific defect of the platelet-vessel wall interaction.  相似文献   
10.
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