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   247525篇
  免费   18704篇
  国内免费   5585篇
耳鼻咽喉   4405篇
儿科学   3337篇
妇产科学   4483篇
基础医学   24758篇
口腔科学   6418篇
临床医学   18712篇
内科学   28192篇
皮肤病学   2860篇
神经病学   14253篇
特种医学   7543篇
外国民族医学   22篇
外科学   39748篇
综合类   33788篇
现状与发展   13篇
一般理论   10篇
预防医学   17005篇
眼科学   6670篇
药学   28104篇
  215篇
中国医学   13279篇
肿瘤学   17999篇
  2024年   193篇
  2023年   4101篇
  2022年   5317篇
  2021年   10181篇
  2020年   9978篇
  2019年   9404篇
  2018年   9310篇
  2017年   9497篇
  2016年   9526篇
  2015年   9121篇
  2014年   12635篇
  2013年   16254篇
  2012年   13097篇
  2011年   15184篇
  2010年   10173篇
  2009年   10135篇
  2008年   11432篇
  2007年   12497篇
  2006年   11620篇
  2005年   10622篇
  2004年   9159篇
  2003年   8001篇
  2002年   6258篇
  2001年   5745篇
  2000年   4835篇
  1999年   4126篇
  1998年   3125篇
  1997年   3142篇
  1996年   2758篇
  1995年   2539篇
  1994年   2428篇
  1993年   2021篇
  1992年   1839篇
  1991年   1741篇
  1990年   1450篇
  1989年   1214篇
  1988年   1175篇
  1987年   1082篇
  1986年   980篇
  1985年   1374篇
  1984年   1121篇
  1983年   829篇
  1982年   856篇
  1981年   710篇
  1980年   673篇
  1979年   520篇
  1978年   329篇
  1977年   289篇
  1976年   267篇
  1975年   205篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
目的 探讨不同时期慢性阻塞性肺疾病(COPD)患者血清诱饵受体3(DcR3)、凋亡抑制蛋白(Survivin)表达水平及临床意义。方法 选取2018年9月—2019年12月本院收治的92名COPD患者为研究对象,其中稳定型COPD 50例,急性加重期COPD 42例;同期本院健康体检者88例为对照组。测定各组研究对象血清DcR3、Survivin水平及肺功能指标。 与对照组[DcR3(106.54±48.35)pg/mL,Survivin(98.85±26.59)pg/mL]比较,稳定期组和急性加重期组血清DcR3[(395.23±123.85)pg/mL,(1 248.81±213.59)pg/mL]、Survivin [(267.54±84.69)pg/mL,(1 233.95±307.26)pg/mL]水平升高;与稳定期组比较,急性加重期组血清DcR3、Survivin水平升高。与对照组比较,稳定期组和急性加重期组FEV1%、FEV1 /FVC、DLCO%水平降低(P<0.001);与稳定期组比较,急性加重期组FEV1%、FEV1 /FVC、DLCO%水平降低(P<0.001)。随着低氧血症严重程度的增加,COPD患者血清DcR3、Survivin水平逐渐增加(P<0.001)。多因素logistics回归分析显示,高水平DcR3、Survivin、IL-12、hs-CRP为COPD病情的危险因素(P<0.001)。DcR3、Survivin与FEV、FEV1 /FVC呈负相关,与IL-12、TNF-α、hs-CRP呈正相关(P<0.001)。 COPD稳定期、急性加重期患者血清DcR3、Survivin表达水平升高,且DcR3、Survivin与COPD病情严重程度呈正相关。  相似文献   
3.
The discussion paper will focus on continuity of care relating to previous NZ research, specifically to transitioning complex preterm infants from NICU to home based on parent experiences, and on the practice developments that have occurred, to ensure optimal health outcomes. Previous NZ research discovered parent desire a consistent service delivery for the entire transition journey from NICU and at home.An informative and comprehensive opportunity has occurred for reflective professional practice, evaluation, development and implementation which have transpired in positive change through innovative practice developments and support change implementation in Wellington, NZ. This has resulted in the articulation of a model of care that has both embraced and integrated parental desires for a continuity of care process for complex preterm infants. This has been achieved by having the same Discharge Facilitator/Key Case Manager present within the NICU and external to the NICU for Home-based infants for the entire transition journey.The paper will focus and emphasis additional practice development changes and furthermore, will present a real purpose, for other countries to learn of such practice developments that have exemplified a celebratory success for families of Wellington, NZ.  相似文献   
4.
5.
Oral and maxillofacial surgery (OMS) teaching is set to undergo a paradigm shift towards competency-based training. With increasing focus on resident skill development and patient safety, computerized simulators are likely to play a more mainstream role in OMS training. A systematic review of the available literature was conducted, in accordance with the PRISMA guidelines, to highlight the scope of computerized simulation in OMS teaching. A PubMed search was performed by two independent reviewers, and 35 articles published in English between 2010 and 2021 that reported the use of computerized simulation for teaching maxillofacial procedures were included in the analysis. Eight articles on minor oral surgery, seven on orthognathic surgery, five on maxillofacial trauma, five on cleft lip and palate surgery, three articles each on nerve block techniques, endoscopic procedures, and reconstructive surgery, and one article on fibre-optic intubation reported the use of computerized simulation that can be applied to OMS training. Ten randomized controlled trials were identified in the search. However there was marked heterogeneity among the studies. Simulator training for skill acquisition mentored by an expert OMS educator could offer holistic resident training; however more studies that test common themes of resident training such as knowledge acquisition and skill development are necessary.  相似文献   
6.
Traditionally, surgical management of zygomaticomaxillary complex (ZMC) and orbital fractures occurs within two to three weeks of the injury, followed by an overnight admission to allow for extended eye observations. This is due to the risk of postoperative retrobulbar haemorrhage (RBH) or orbital compartment syndrome (OCS), a rapidly progressive and sight threatening emergency that requires immediate intervention. In September 2016 the oral and maxillofacial surgery (OMFS) department at Leeds Teaching Hospitals redesigned their trauma service with a full-time trauma consultant, a dedicated clinic, and a weekly morning elective trauma theatre list. This allowed for standardisation of the management of patients with OMFS injuries. Furthermore, a formal day-case ZMC and orbital fracture pathway was developed to allow patients to undergo surgical management of such fractures with a same-day discharge. This has since been identified as an area of excellence by the Getting It Right First Time (GIRFT) programme, and is in line with the addition of ZMC and orbital fractures to the procedural list written by the British Association of Day Case Surgery (BADS). Unbeknown to the unit, the volume of day-case procedures was the highest within the UK, demonstrating the importance of GIRFT in highlighting areas of good or unique practice. The aim of this study was to determine the impact of our day-case pathway and designated OMFS trauma service on compliance with recent recommendations by GIRFT and BADS. Secondly, it was to determine the safety of same-day discharge with regards to postoperative complications.  相似文献   
7.
8.
Transfusion-associated graft-versus-host disease (TA-GVHD) is a rare life-threatening complication of blood transfusion caused by donor T cells that escape rejection by the recipient immune system. These donor T cells drive recipient tissue damage in response to host antigens. On the other hand, GVHD occurring after allogeneic hematopoietic cell transplantation (HCT-GVHD) is also caused by donor T cells, but its pathophysiology is more complex and differs due to the effects of tissue damage caused by pre?HCT conditioning and profound immunosuppression. Both TA-GVHD and HCT-GVHD can be fatal; however, mortality is higher with TA-GVHD due to the paucity of treatment options. Here, we compare and summarize the presentation, diagnosis, pathophysiology, prevention, and treatment of TA-GVHD and HCT-GVHD.  相似文献   
9.
针对日常使用中遇到的Brilliance 16排螺旋CT高压系统、机架以及控制器局域网络(CAN)通讯等故障现象进行分析与维修,最终通过更换滤波电容、机架数据采集控制器(DMC)电源以及信号刷等配件得以排除故障。通过对故障准确判断以及合理运用厂家Service模式下的维修工具软件快速解决故障,保障了影像科检查工作的顺利进行,从而提高设备的稳定性。  相似文献   
10.
Species identification of unknown biological samples is crucial for forensic applications, especially in cases of explosion, disaster accidents, and body mutilation after murdering, as well as poaching, illegal trade in endangered animals, and meat food fraud. In this study, we identified 60 volatile organic compounds (VOCs) in fresh skeletal muscle tissues of seven different animal species (cattle, sheep, pigs, rabbits, rats, chickens and carp) and a human dead body by headspace-gas-chromatography ion-mobility spectrometry (HS-GC-IMS), and compared their differences by retention time, drift time and molecular weight. The results showed that these VOCs formed different gallery plot fingerprints in the skeletal muscle tissues of the human dead body and seven animal species. Principal component analysis (PCA) showed significantly different fingerprints between these species, and these fingerprints maintained good stability between the species and within the same species. Some VOCs have high species specificity, while VOCs of human fresh muscle tissues from different individual sources have little difference, demonstrating that all tested muscle tissue samples could be distinguished based on different VOCs. HS-GC-IMS has proved to be a rapid, high-throughput, highly sensitive and specific species identification method, which can be used for forensic species identification in criminal cases and disaster accidents, as well as detection in the field of food safety, such as meat fraud and adulteration.  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