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   1668篇
  免费   148篇
  国内免费   27篇
耳鼻咽喉   7篇
儿科学   36篇
妇产科学   6篇
基础医学   183篇
口腔科学   23篇
临床医学   159篇
内科学   237篇
皮肤病学   10篇
神经病学   58篇
特种医学   44篇
外科学   66篇
综合类   413篇
预防医学   290篇
眼科学   7篇
药学   80篇
  2篇
中国医学   186篇
肿瘤学   36篇
  2024年   6篇
  2023年   42篇
  2022年   75篇
  2021年   88篇
  2020年   91篇
  2019年   83篇
  2018年   62篇
  2017年   84篇
  2016年   82篇
  2015年   52篇
  2014年   129篇
  2013年   108篇
  2012年   130篇
  2011年   118篇
  2010年   81篇
  2009年   79篇
  2008年   78篇
  2007年   73篇
  2006年   61篇
  2005年   56篇
  2004年   34篇
  2003年   34篇
  2002年   24篇
  2001年   29篇
  2000年   16篇
  1999年   17篇
  1998年   15篇
  1997年   8篇
  1996年   6篇
  1995年   5篇
  1994年   11篇
  1993年   7篇
  1992年   13篇
  1991年   6篇
  1990年   7篇
  1989年   6篇
  1987年   2篇
  1985年   2篇
  1984年   5篇
  1983年   4篇
  1981年   1篇
  1980年   3篇
  1979年   1篇
  1976年   1篇
  1975年   1篇
  1974年   1篇
  1973年   1篇
  1971年   1篇
  1970年   1篇
  1969年   1篇
排序方式: 共有1843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.
壮精合剂治疗围绝经期综合征58例   总被引:1,自引:0,他引:1  
目的:探讨壮精合剂治疗围绝经期综合征的临床疗效。方法:选取符合围绝经期综合征诊断标准的病人58例,应用壮精合剂加减口服治疗1~2个月。结果:显效31例占53.4%;有效23例占39.7%;无效4例占6.9%,总有效率为93%。结论:壮精合剂治疗围绝经期综合征能收到良好的临床疗效。  相似文献   
4.
朱红梅  苏东兵 《中医药学刊》2007,25(12):2482-2483
目的:观察壮医针挑并艾灸对糖尿病周围神经病变200例的疗效。方法:取龙路、火路网络在体表的反应穴或皮下反应点,每次选2~3个穴位,持针尖快速刺入皮肤0.1~0.2cm,绞断表皮少许纤维,尽量不出血,每3天1次,配合艾灸,10次为1疗程。结果:显效102例,有效78例,无效20例。总有效率为90%。结论:壮医针挑并艾灸治疗糖尿病周围神经病变疗效仍显著。  相似文献   
5.
广西巴马长寿乡壮族长寿老人永生细胞库的建立   总被引:3,自引:0,他引:3  
目的:建立广西巴马长寿乡壮族长寿老人永生细胞库。方法:使用EB病毒转化外周血B淋巴细胞方法。结果:建立了长寿者外周血细胞转化永生细胞株的方法,转化成功率77.4%。建立了65株长寿老人、直系亲属永生细胞株及长寿老人资料库和完整的细胞株档案。结论:广西巴马长寿乡壮族长寿老人永生细胞库的建立为永久保存细胞系及后续研究提供了必要的基础。  相似文献   
6.
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   
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.
月经初潮年龄对壮族女大学生体型分布的影响   总被引:2,自引:0,他引:2  
目的 探讨月经初潮年龄对女大学生体型分布的影响。方法 对 10 3名 2 0岁壮族女大学生的月经初潮年龄进行调查研究 ,并作Heath Carter体型分析。结果 得出 4个不同月经初潮年龄组的体型均值和 10 3名 2 0名壮族女大学生的体型均值 ,表明均为三胚中间型体型。结论 壮族女大学生的体型不受月经初潮年龄的影响。  相似文献   
9.
The ribosomal DNA from the Zygomycete Mucor miehei has been characterised. The complete rDNA unit was cloned by heterologous PCR using primers whose sequence matched conserved regions of the rDNA from related fungal species. The sequence of the overlapping PCR products revealed the existence of a repeated unit of 9574 bp. The genes encoding the different rRNA species were identified by their homology to the corresponding sequences from other fungi. We estimate that the rDNA unit is present in the genome of M. miehei in about 100 copies. This estimation was made by comparing the intensity of its hybridisation signal in a Southern blot with that of the mmp gene coding for aspartyl protease, which was assumed to be contained in single copy. The size and structure of the M. miehei rDNA unit was similar to that of other fungi. The genes encoding the 25S, 18S and 5.8S RNAs are closely linked within the repeated unit which also contains the 5S gene. This latter gene appears to be transcribed in the opposite direction. The 25S, 18S and 5.8S genes showed 70–80% homology to the corresponding genes from other fungi, whereas the degree of homology for the 5S gene was much lower. The highest homology (about 80%) corresponded to the few available sequences from other Mucor species. Homology to genes from other Zygomycota was no higher than that observed for genes from the Ascomycota or Basidiomycota fungi. Received: 21 December 1999 / 1 March 2000  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