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   2557篇
  免费   176篇
  国内免费   41篇
耳鼻咽喉   13篇
儿科学   156篇
妇产科学   15篇
基础医学   133篇
口腔科学   47篇
临床医学   239篇
内科学   236篇
皮肤病学   23篇
神经病学   155篇
特种医学   84篇
外科学   203篇
综合类   427篇
预防医学   501篇
眼科学   19篇
药学   291篇
  2篇
中国医学   169篇
肿瘤学   61篇
  2024年   7篇
  2023年   63篇
  2022年   141篇
  2021年   168篇
  2020年   134篇
  2019年   103篇
  2018年   91篇
  2017年   71篇
  2016年   77篇
  2015年   81篇
  2014年   211篇
  2013年   155篇
  2012年   202篇
  2011年   202篇
  2010年   137篇
  2009年   140篇
  2008年   123篇
  2007年   131篇
  2006年   113篇
  2005年   70篇
  2004年   62篇
  2003年   39篇
  2002年   43篇
  2001年   28篇
  2000年   21篇
  1999年   29篇
  1998年   14篇
  1997年   6篇
  1996年   11篇
  1995年   11篇
  1994年   14篇
  1993年   6篇
  1992年   7篇
  1991年   9篇
  1990年   5篇
  1989年   3篇
  1987年   6篇
  1986年   5篇
  1985年   2篇
  1984年   5篇
  1983年   7篇
  1982年   8篇
  1981年   1篇
  1980年   3篇
  1978年   1篇
  1977年   2篇
  1976年   2篇
  1973年   1篇
  1972年   1篇
  1969年   1篇
排序方式: 共有2774条查询结果,搜索用时 15 毫秒
1.
《Vaccine》2020,38(45):7118-7128
IntroductionToward the Global Vaccine Action Plan 2020 goal, almost 90% of countries have established a National Immunization Technical Advisory Group (NITAG). However, little is known about NITAG's contributions to governance.MethodsIn 2017–2018, a two-step, qualitative retrospective study was conducted. Jordan (JO), Argentina (AR), and South Africa (SA) were selected owing to government-financed NITAGs from middle-income countries (MICs), geographic diversity, and a vaccine introduction with NITAG support. Country case studies were developed, collecting data through desk review and face-to-face key informant interviews (KIIs) from Ministry of Health (MoH) and NITAG. Case studies were analyzed together, to assess governance applying the European Observatory on Health Systems and Policies framework focusing on transparency, accountability, participation, integrity, and policy capacity (TAPIC).ResultsDocument review and 53 KII (22 AR, 20 SA, 11 JO) showed NITAGs played a pivotal role as advisors promoting a culture of evidence-informed policies. NITAGs strengthened governance, although practices varied among countries. Meetings were conducted behind-closed-doors, participation restricted to members, only in one country agendas, and recommendations were public (AR). To increase participation, policy capacity, and transparency, countries considered adding experts in communications, advocacy, and economics. AR and SA contemplated including community members. NITAGs functioned autonomously from the government, with no established internal or external monitoring or supervision. NITAG meeting minutes allowed the review of integrity, adherence to terms of reference, standard operating procedures, and conflict of interest (CoI). For the most part, NITAGs abided by their mandates. Significant issues were related to the level of MoH support and oversight of CoI declaration and documentation.ConclusionsSystematically implementing governance approaches could improve processes, better tailor policies, and implementation. The long-term survival and resilience of NITAGs in these countries showed they play a significant role in strengthening governance. Lessons learned could be useful to those promoting country-driven evidence-informed decision-making.  相似文献   
2.
PurposeTo compare morphological imaging features and CT texture histogram parameters between grade 3 pancreatic neuroendocrine tumors (G3-NET) and neuroendocrine carcinomas (NEC).Materials and methodsPatients with pathologically proven G3-NET and NEC, according to the 2017 World Health Organization classification who had CT and MRI examinations between 2006-2017 were retrospectively included. CT and MRI examinations were reviewed by two radiologists in consensus and analyzed with respect to tumor size, enhancement patterns, hemorrhagic content, liver metastases and lymphadenopathies. Texture histogram analysis of tumors was performed on arterial and portal phase CT images. images. Morphological imaging features and CT texture histogram parameters of G3-NETs and NECs were compared.ResultsThirty-seven patients (21 men, 16 women; mean age, 56 ± 13 [SD] years [range: 28-82 years]) with 37 tumors (mean diameter, 60 ± 46 [SD] mm) were included (CT available for all, MRI for 16/37, 43%). Twenty-three patients (23/37; 62%) had NEC and 14 patients (14/37; 38%) had G3-NET. NECs were larger than G3-NETs (mean, 70 ± 51 [SD] mm [range: 18 - 196 mm] vs. 42 ± 24 [SD] mm [range: 8 - 94 mm], respectively; P = 0.039), with more tumor necrosis (75% vs. 33%, respectively; P = 0.030) and lower attenuation on precontrast (30 ± 4 [SD] HU [range: 25-39 HU] vs. 37 ± 6 [SD] [range: 25-45 HU], respectively; P = 0.002) and on portal venous phase CT images (75 ± 18 [SD] HU [range: 43 - 108 HU] vs. 92 ± 19 [SD] HU [range: 46 - 117 HU], respectively; P = 0.014). Hemorrhagic content on MRI was only observed in NEC (P = 0.007). The mean ADC value was lower in NEC ([1.1 ± 0.1 (SD)] × 10−3 mm2/s [range: (0.91 - 1.3) × 10−3 mm2/s] vs. [1.4 ± 0.2 (SD)] × 10−3 mm2/s [range: (1.1 - 1.6) × 10−3 mm2/s]; P = 0.005). CT histogram analysis showed that NEC were more heterogeneous on portal venous phase images (Entropy-0: 4.7 ± 0.2 [SD] [range: 4.2-5.1] vs. 4.5 ± 0.4 [SD] [range: 3.7-4.9]; P = 0.023).ConclusionPancreatic NECs are larger, more frequently hypoattenuating and more heterogeneous with hemorrhagic content than G3-NET on CT and MRI.  相似文献   
3.
PurposeTo evaluate the potential differences in non-target embolization and vessel microsphere filling of a reflux-control microcatheter (RCM) compared to a standard end-hole microcatheter (SEHM) in a swine model.Materials and methodsRadiopaque microspheres were injected with both RCM and SEHM (2.4-Fr and 2.7-Fr) in the kidneys of a preclinical swine model. Transarterial renal embolization procedures with RCM or SEHM were performed in both kidneys of 14 pigs. Renal arteries were selectively embolized with an automated injection protocol of radio-opaque microspheres. Ex-vivo X-ray microtomography images of the kidneys were utilized to evaluate the embolization by quantification of the deposition of injected microspheres in the target vs. the non-target area of injection. X-ray microtomography images were blindly analyzed by five interventional radiologists. The degree of vessel filling and the non-target embolization were quantified using a scale from 1 to 5 for each parameter. An analysis of variance was used to compare the paired scores.ResultsTotal volumes of radio-opaque microspheres injected were similar for RCM (11.5 ± 3.6 [SD] mL; range: 6–17 mL) and SEHM (10.6 ± 5.2 [SD] mL; range: 4–19 mL) (P = 0.38). The voxels enhanced ratio in the target (T) vs. non-target (NT) areas was greater with RCM (T = 98.3% vs. NT = 1.7%) than with SEHM (T = 89% vs. NT = 11%) but the difference was not significant (P = 0.30). The total score blindly given by the five interventional radiologists was significantly different between RCM (12.3 ± 2.1 [SD]; range: 6–15) and the standard catheter (11.3 ± 2.5 [SD]; range: 4–15) (P = 0.0073), with a significant decrease of non-target embolization for RCM (3.8 ± 1.3 [SD]; range: 3.5–4.2) compared to SEHM (3.2 ± 1.5 [SD]; range: 2.9–3.5) (P = 0.014).ConclusionIn an animal model, RCM microcatheters reduce the risk of non-target embolization from 11% to 1.7%, increasing the delivery of microspheres of 98% to the target vessels, compared to SEHM microcatheters.  相似文献   
4.
5.
Background: The Rhinitis Symptom Utility Index (RSUI), originally developed in the United States, consists of a patient-preference weighting scheme and a 10-item questionnaire measuring the severity and frequency of rhinitis related symptoms over a 14-day period. This study aimed to determine whether the Chinese RSUI could adopt the US-based multi-attribute utility function (MAUF) in scoring rhinitis symptoms. Methods: In a Hong Kong study, 116 Chinese adults with allergic rhinitis completed the RSUI questionnaire and 36-item Short-Form Health Survey (SF-36) after they had been seen by two otorhinolaryngologists for disease-severity ratings. Respondents then completed computer-administered direct preference measures, i.e., visual analogue scale (VAS) and standard gamble (SG) assessments. The VAS and SG data were used to estimate a MAUF for the Chinese-based RSUI. Results: The derived MAUF was somewhat different than the one developed for the US RSUI. Test–retest reliability for the Chinese RSUI was satisfactory (ICC = 0.71, p<0.001). Scores differentiated among cases with mild, moderate, and severe symptoms (p<0.001); and between those who did and did not require medications to control symptoms (p = 0.031). Findings were significantly correlated with SF-36 domain scores (r = 0.19 to 0.37; p=0.041 to <0.001). When the US-based scoring function was applied to the Chinese subjects, the resulting mean RSUI score was significantly lower (p<0.001). Comparisons between directly measured VAS and SG scores between the US and Chinese samples, demonstrated significant differences (all p<0.05), with the US subjects consistently rating rhinitis symptoms as worse than Chinese subjects. Conclusions: The Chinese RSUI has good measurement properties that reflect patient preferences from the Chinese. Results suggest that there are differences in preference rating between US and Chinese subjects and that use of the US-based preference function for the RSUI would bias the measurement of rhinitis symptom outcomes in Chinese subjects.  相似文献   
6.
李晴辉  李刚荣  周琳 《重庆医学》2007,36(23):2369-2371
目的本文以医院信息系统(hispitalinformation system,HIS)系统实施的一般规律为例,讨论了HIS系统实施的一般规律,深入探讨了范围变更产生的原因、接受依据以及管理技术,对于HIS系统实施中最常发生的范围变更管理提出了对策,以使医院业务与HIS软件系统有机会结合在一起,真正实现医院业务信息化的目标。方法文章认为,系统范围变更管理应贯穿于系统实施过程的始终,每一项需求变更都应分析其产生的原因、对医院业务的影响和对系统实施的影响,以确定是否接受范围变更。结果当决定接受或拒绝范围变更申请时,信息科都应与提供产品公司的实施工程师沟通。结论在范围变更管理中,要充分使用好文档模板,并制定出规范的范围变更管理流程,以提高范围变更管理效率。  相似文献   
7.
8.
江门市区实施乙型肝炎免疫策略16年的效果评价   总被引:6,自引:5,他引:1  
目的:对江门市区1986年1月1日起全面实施的乙型肝炎(乙肝)免疫策略进行效果评价。方法:运用血清流行病学调查和疫情资料对比分析,比较实施“免疫策略”前后江门市区0~15岁人群乙肝发病率和感染率变化情况和乙肝表面抗体(抗-HBs)增长情况。结果:实施“免疫策略”后16年,0~15人群的乙肝发病率由1985年的367.39/10万,降至2001年的21.10/10万,下降94.26%;HBsAg阳性率由1985年的9.17%降至2002年的0.6%,下降93.46%;乙肝病毒总感染率由1985年的35.82%降至2002年的1.20%,下降96.65%;抗-HBs阳性率由1985年的24.64%上升到2002年的93.00%,上升2.77倍。结论:江门市区现行乙肝免疫策略效果显,能有效预防和控制地区性大面积的乙肝流行与传播。经过一代人的努力,能彻底改变人口乙肝高发病率和HBV高感染率及高携带率的状况。  相似文献   
9.
目的研究标准化个人健康档案的内容及其标准化指标体系。方法综合采用定性方法和定量方法。结果将个人生命周期分为九个阶段,依据不同阶段的主要健康问题、相关危险因素和主要健康事件设计出完整的健康档案内容及指标体系,并确定标准值域。结论标准化健康档案的内容能够满足按照生命周期进行健康管理的要求。同时也还需要实践的进一步检验和调整。  相似文献   
10.
目的探讨PET-CT一体机在恶性肿瘤中的应用价值.方法收集已经明确诊断的全身不同部位的恶性肿瘤病例62例,经PET-CT检查后进行回顾性分析,采用目测和半定量分析方法.结果62例肿瘤病人共检出142个病灶,PET图像阳性率93.55%(58/62);PET图像阴性率6.45%(4/62);PET发现病灶而CT未完全发现病灶率19.4%(12/62);CT发现而PET未见浓聚率6.45%(4/62);原发灶未能找到率1.61%(1/62).标准化摄取值(SUV)大于2.5占78.2%(111/142);SUV2.5~2.0占14.8%(21/142);SUV小于2.0占7%(10/142).结论PET-CT与单纯PET,CT比较具有明显的优势,可以精确定位、定性,但PET-CT也有一定的局限性.  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