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   1581篇
  免费   102篇
  国内免费   24篇
耳鼻咽喉   10篇
儿科学   36篇
妇产科学   14篇
基础医学   180篇
口腔科学   23篇
临床医学   167篇
内科学   220篇
皮肤病学   4篇
神经病学   75篇
特种医学   40篇
外科学   71篇
综合类   257篇
预防医学   441篇
眼科学   8篇
药学   61篇
  1篇
中国医学   62篇
肿瘤学   37篇
  2024年   2篇
  2023年   38篇
  2022年   63篇
  2021年   76篇
  2020年   64篇
  2019年   63篇
  2018年   66篇
  2017年   59篇
  2016年   64篇
  2015年   47篇
  2014年   86篇
  2013年   115篇
  2012年   94篇
  2011年   134篇
  2010年   83篇
  2009年   81篇
  2008年   97篇
  2007年   77篇
  2006年   77篇
  2005年   52篇
  2004年   29篇
  2003年   32篇
  2002年   32篇
  2001年   28篇
  2000年   17篇
  1999年   25篇
  1998年   13篇
  1997年   17篇
  1996年   11篇
  1995年   10篇
  1994年   10篇
  1993年   7篇
  1992年   3篇
  1991年   2篇
  1990年   6篇
  1989年   6篇
  1988年   3篇
  1987年   1篇
  1985年   1篇
  1984年   2篇
  1983年   4篇
  1982年   1篇
  1981年   1篇
  1980年   3篇
  1979年   1篇
  1976年   1篇
  1971年   1篇
  1970年   1篇
  1969年   1篇
排序方式: 共有1707条查询结果,搜索用时 187 毫秒
1.
2.
《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   
3.
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   
4.
目的 探讨基层药品不良反应监测网络建设模式,为药品不良反应监测组织体系的完善提供参考.方法 通过建立山东省基层药品不良反应监测网络的实践,研究、分析基层药品不良反应监测网络的建设模式.结果 建立了高效、快捷的三级药品不良反应监测网络,促进了山东省药品不良反应监测工作的全面发展.结论 建立健全机构设施完备、职责明确、运作规范的基层监测网络,有利于完善我国药品不良反应监测组织体系,推动药品不良反应监测工作的深入开展.  相似文献   
5.
少数民族女大学生性与避孕行为调查   总被引:1,自引:1,他引:0  
目的:了解少数民族女大学生性与避孕行为状况。方法:在武汉地区,对各大学的少数民族女大学生进行了抽样调查。结果:调查了286名少数民族女大学生,其性行为率为14.68%,不同专业和不同年级的女大学生性行为率有统计学差异。女大学生性行为的原因以一时感情冲动、好奇、为了加强与男友的关系、生理需要为主,还有迫于暴力等原因。性伴侣以自己的男朋友为主(占95.23%以上),但也有一般熟人和一夜情对象;另有多性伴现象存在。发生性行为者中,初次性行为有42.85%未采取任何避孕措施;在近1年内有性行为者中,有54.54%的人每次性行为都采取了避孕措施。在性行为者中,有23.81%的学生怀孕,另有19.05%的学生患生殖系统炎症或性病。结论:少数民族女大学生中的性行为发生率较高,她们中存在性滥、怀孕和性传播疾病等问题。  相似文献   
6.
海南省黎族中学生艾滋病知识干预效果分析   总被引:3,自引:0,他引:3  
目的:通过干预提高黎族中学生的艾滋病知识水平,降低黎族人群感染艾滋病的危险。方法:采用集中授课、播发VCD等方式进行干预,利用自行设计的调查表对干预对象进行相关知识调查。结果:干预后中学生对艾滋病相关知识的认识均有不同程序的提高,最高提高22.90个百分点,最低提高6.50个百分点,平均提高15.46个百分点;艾兹病知识主要来源于电视广播和医生,分别占58.00%和22.00%。结论:在黎族中学生中开展艾滋病健康教育是完全可行且是十分必要的,应该引起重视。  相似文献   
7.
枕骨大孔区腹侧脑膜瘤的显微手术技术探讨   总被引:1,自引:0,他引:1  
目的探讨远外侧入路在治疗枕骨大孔区腹侧脑膜瘤中的应用。方法对14例脑膜瘤患者采用远外侧入路显微手术治疗,其中枕髁后入路8例,经部分枕髁入路3例,经C1、2关节面侧方联合部分枕髁入路2例,经完整枕髁入路1例。结果肿瘤全切11例,次全切除3例;1例行枕颈融合,无手术死亡病例。所有患者术后均未出现寰枕关节不稳定的症状,手术并发症主要是后组颅神经损伤、椎动脉损伤、脑脊液漏以及脑干缺血。结论远外侧入路是手术治疗下斜坡区和上段颈髓腹侧、腹外侧病变的理想入路,可以理想显露肿瘤及其基底部并减少术中出血,但手术操作比较复杂且具有一定的风险。  相似文献   
8.
目的了解那曲地区藏族学生龋病患病情况,为当地制定口腔预防保健措施提供基线资料。方法采用单纯随机抽样方法,按照WHO 1997年的《口腔健康调查基本方法》,对12~17岁的471名藏族学生进行恒牙龋病检查。结果藏族学生恒牙总患龋率为56.7%,男生患龋率为53.9%,女生患龋率为59.1%,差异无统计学意义(χ2=1.258,P=0.262);龋均为(4.09±2.11),男生龋均为(4.04±2.10),女生龋均为(4.13±2.11),差异无统计学意义(t=-0.646,P=0.518)。结论那曲地区藏族学生恒牙龋病患病率较高、程度较重,预防治疗措施急需加强。  相似文献   
9.
以统一的流调方法和诊断标准,在500户彝族家庭中对118名60岁以上的农村老人进行了精神卫生流行病学调查。结果显示,老年期精神疾病患病率为5.08%,主要是酒精依赖。  相似文献   
10.
A new approach to the automatic extraction of the lumen region and its boundary for gastrointestinal (GI) endoscopic images is presented. First, a quasi region of interest, the darker regions of the image, is segmented using a region splitting scheme termed progressive thresholding. The centre of mass of this segmented region acts as a seed for further processing. Then the lumen region is obtained using a region growing technique called the integrated neighbourhood search (INS). A new quad structure based technique is introduced to enhance the INS speed significantly. A back projection algorithm is suggested to optimise the search for pixels belonging to the lumen region and boundary. A boundary-thinning algorithm is also proposed to remove the redundant pixels from the lumen boundary and to generate a connected single pixel width boundary. The proposed approach does not need a priori knowledge about the image characteristics. The experimental results indicate that the proposed technique enhances the speed of conventional INS by 45.5% to 28.6% based on the lumen size varying from 22,709 pixels to 4947 pixels. The main advantage of the proposed technique is its high-speed response that facilitates real-time analysis of endoscopic images.  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