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   13752篇
  免费   1216篇
  国内免费   412篇
耳鼻咽喉   83篇
儿科学   111篇
妇产科学   498篇
基础医学   857篇
口腔科学   329篇
临床医学   1897篇
内科学   731篇
皮肤病学   63篇
神经病学   306篇
特种医学   529篇
外科学   756篇
综合类   2791篇
一般理论   5篇
预防医学   2324篇
眼科学   125篇
药学   1929篇
  59篇
中国医学   1753篇
肿瘤学   234篇
  2024年   78篇
  2023年   337篇
  2022年   570篇
  2021年   789篇
  2020年   749篇
  2019年   536篇
  2018年   563篇
  2017年   617篇
  2016年   642篇
  2015年   591篇
  2014年   1159篇
  2013年   1461篇
  2012年   1094篇
  2011年   1066篇
  2010年   764篇
  2009年   655篇
  2008年   680篇
  2007年   571篇
  2006年   512篇
  2005年   382篇
  2004年   312篇
  2003年   257篇
  2002年   183篇
  2001年   154篇
  2000年   123篇
  1999年   88篇
  1998年   59篇
  1997年   64篇
  1996年   65篇
  1995年   53篇
  1994年   38篇
  1993年   21篇
  1992年   31篇
  1991年   16篇
  1990年   19篇
  1989年   12篇
  1988年   13篇
  1987年   13篇
  1986年   9篇
  1985年   6篇
  1984年   5篇
  1983年   5篇
  1982年   6篇
  1981年   2篇
  1980年   4篇
  1979年   1篇
  1978年   1篇
  1976年   1篇
  1974年   1篇
  1973年   2篇
排序方式: 共有10000条查询结果,搜索用时 984 毫秒
81.
根据七年制医学生培养要求,在“生物物理技术”教学中,除介绍有关物理方法与技术的原理及在生物医学中的应用外,还尝试了小论文写作和渗透科研思路、方法培养的探索。  相似文献   
82.
Despite the growing interest in adopting information technology (IT) in healthcare, the degree of technology sophistication varies among healthcare organizations. Changes in the health care sector and continuous pressure to improve the quality of care have driven the evolution of IT in hospitals. This paper provides an overview of clinical IT sophistication in a sample of U.S. hospitals, and compares clinical IT capacities in this sample with a sample of Canadian hospitals. The instrument used for the comparison measures three clinical dimensions of IT sophistication: functional sophistication, technological sophistication and integration level. Clinical areas that were considered include patient management, patient care activities and clinical support activities. The comparison between hospitals in Iowa and Canada shows differences in clinical IT sophistication between the two settings. Hospitals in Iowa appear to have more technologies but fewer computerized processes and integration of patient management activities. Technological sophistication however, was low in both samples. Our findings confirm the construct validity of the measurement instrument and show initial evidence of its generalizability. More initiatives using the instrument would lead to enhancement in IT assessment tools that can be used for evaluation of IT in relation to patient management and quality outcomes.  相似文献   
83.
cDNA arrays are a powerful tool for the identification of differentially expressed genes in malignant tumors. We used this technique to study the gene expression profiles of anaplastic large cell lymphoma (ALCL) and Hodgkin's disease (HD). Gene expression of 11 lymphoma cell lines was analyzed covering 1176 cDNA sequences. Comparing these data to the expression profiles of B- and T-lymphocytes, we identified 27 genes that were deregulated in all cell lines or in a particular entity. For the establishment of gene expression profiles the 27 genes were assigned to four groups composed of genes deregulated in (i) all lymphoma cell lines, (ii) ALCL and HD, (iii) only HD, and (iv) ALCL exclusively. Our results indicate that ALCL and HD share the differential expression of at least five genes. In addition, both entities are characterized by the differentially deregulated expression of four genes in HD and seven genes in ALCL. Because the expression profiling was performed on cell lines, further studies are needed to clarify the biological significance of the differentially expressed genes.  相似文献   
84.
Impact of elective single embryo transfer on the twin pregnancy rate   总被引:9,自引:0,他引:9  
BACKGROUND: It is unclear how the implementation of elective single embryo transfer in clinical practice would affect clinical pregnancy and delivery rates and multiple birth rates. METHODS: This retrospective study analysed 1871 IVF/ICSI cycles carried out from 1997 to 2001 in the IVF programme of a single university infertility clinic. RESULTS: The number of elective single embryo transfers increased from 11 to 56%. At the same time the clinical pregnancy rate was relatively stable; mean 34.0% (range 28-42). The number of embryos per embryo transfer decreased from 1.8 to 1.3. The multiple pregnancy and delivery rates dropped markedly from 25 to 7.5% and from 25 to 5% respectively. CONCLUSIONS: An elective single embryo transfer programme can be adopted in daily practice that decreases the twinning rate to <10% and does not affect the overall pregnancy rate.  相似文献   
85.
目的: 探讨前列地尔脂微球(liposome prostaglandin E1,Lipo-PGE1) 不同用药时间和途径对肝脏血流灌注的作用机制。方法: 选取健康成年犬12只,经左小隐静脉注射Lipo-PGE11 μg/kg,速度均为0.05 μg·kg-1·min-1。分别于0 min、5 min、15 min、30 min后行肝脏CT灌注成像(computed tomography perfusion imaging,CTPI)扫描,计算肝动脉灌注量(hepatic arterial perfusion,HAP)、门静脉灌注量 (portal vein perfusion,PVP)、总肝灌注量(total liver perfusion,TLP),对照分析不同时间Lipo-PGE1对肝脏血流灌注的影响。选取健康成年犬24只,随机平均分成4组:对照组、外周静脉用药组、肝动脉组、肠系膜上动脉组。Lipo-PGE1的用药量均为1 μg/kg、用药速度均为0.05 μg·kg-1·min-1,0.9%生理盐水用量为20 mL。各组用药5 min后行肝脏CTPI,比较分析不同途径给予Lipo-PGE1对肝脏血流灌注的影响。结果: 经外周静脉注射Lipo-PGE10 min、5 min、15 min、30 min后CTPI测量的HAP(mL·min-1·mL-1)分别为:0.22 ±0.65、0.24±0.65、0.22±0.69、0.22±0.06;PVP (mL·min-1·mL-1):1.22±0.40、1.88±0.59、1.55±0.55、1.29 ±0.57;TLP (mL·min-1·mL-1)分别为:1.44±0.42、2.12±0.61、1.77±0.56、1.51±0.58。方差分析显示HAP组间比较无显著差异(F=0.249,P>0.05),而PVP、TLP组间比较有显著差异(F=3.812,P<0.05)、(F=3.805,P<0.05)。5 min组PVP、TLP增加最为显著,15 min、30 min时两者仍处于高值水平。对照组和外周静脉组、肝动脉组、肠系膜上动脉组的HAP (mL·min-1·mL-1)分别为:0.22±0.06、0.24±0.06、0.31±0.07、0.26±0.05;PVP (mL·min-1·mL-1)分别为1.28±0.38、2.33±0.41、2.37±0.55、2.83±0.94;TLP (mL·min-1·mL-1)分别为:1.50±0.40、2.57±0.42、2.67±0.58、3.09±0.94。方差分析显示HAP组间比较无显著差异(F=2.248,P>0.05),而PVP、TLP组间比较有显著差异(F=6.892,P<0.01)、(F=7.802,P<0.01)。经肠系膜上动脉给药较其它途径给药PVP、TLP增加趋势更为显著。结论: Lipo-PGE1能显著增强肝脏血流灌注,且主要影响门静脉灌注分量,介入技术可为快速改善肝血流灌注提供有效途径。  相似文献   
86.
Traditionally, radiology has been conceived as a support department providing patient scanning services to the other clinical departments in a hospital. However, recent advancements in networking technology and related information systems such as picture archiving and communication system (PACS) and radiology information system (RIS) provide new opportunities for inventing different types of diagnostic imaging businesses such as teleradiology. In this article, we examined the business processes of currently operating imaging centers and proposed a prototype of an information system that can facilitate their workflows in a more efficient way. The principal component of our proposed system is a report management module built on extensible markup language (XML) technologies that allows much flexibility and convenience for both imaging technicians and radiologists.  相似文献   
87.
88.
The legislative background and current responsibilities of the new National Center for Health Care Technology (NCHCT) are discussed. The NCHCT's charge is to consider the stage of development, the actual or potential risks, costs and rate of use of health care technology. The role of Government in supporting new technologies, stimulating innovation and encouraging application of research products is considered. These issues are discussed in the context of the uncertainty inherent in planning and the formulation of public policy.  相似文献   
89.
90.
由于人体组织中存在血液对流传热和代谢产热,当皮肤表面绝热后,皮肤表面的温度将上升,体表温升值是人体组织中血液灌注率和动脉血温度的函数,根据实际测量的体表温升与时间的关系就可以测出活体组织的血液灌注率和动脉血温度。根据一维Pennes生物传热方程,推导出了体表绝热后人体组织中及皮肤表面温度分布的解析解,并对人体组织中的血液灌注率及动脉血温度进行了实验测量。由于测量过程中利用的只是皮肤表面的温度信息,无须引入外加热源,对人体组织完全不会造成损伤,亦避免了干扰人体组织的正常生理状态,整个测量系统也比较简单。  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