全文获取类型
收费全文 | 19848篇 |
免费 | 1854篇 |
国内免费 | 391篇 |
专业分类
耳鼻咽喉 | 76篇 |
儿科学 | 222篇 |
妇产科学 | 82篇 |
基础医学 | 2080篇 |
口腔科学 | 446篇 |
临床医学 | 2952篇 |
内科学 | 2813篇 |
皮肤病学 | 106篇 |
神经病学 | 1323篇 |
特种医学 | 280篇 |
外科学 | 806篇 |
综合类 | 2205篇 |
现状与发展 | 4篇 |
一般理论 | 7篇 |
预防医学 | 4342篇 |
眼科学 | 169篇 |
药学 | 3041篇 |
17篇 | |
中国医学 | 836篇 |
肿瘤学 | 286篇 |
出版年
2024年 | 41篇 |
2023年 | 340篇 |
2022年 | 436篇 |
2021年 | 985篇 |
2020年 | 813篇 |
2019年 | 764篇 |
2018年 | 676篇 |
2017年 | 719篇 |
2016年 | 730篇 |
2015年 | 826篇 |
2014年 | 1255篇 |
2013年 | 1742篇 |
2012年 | 1155篇 |
2011年 | 1291篇 |
2010年 | 1039篇 |
2009年 | 1028篇 |
2008年 | 954篇 |
2007年 | 927篇 |
2006年 | 776篇 |
2005年 | 733篇 |
2004年 | 587篇 |
2003年 | 570篇 |
2002年 | 427篇 |
2001年 | 395篇 |
2000年 | 359篇 |
1999年 | 322篇 |
1998年 | 281篇 |
1997年 | 223篇 |
1996年 | 219篇 |
1995年 | 142篇 |
1994年 | 163篇 |
1993年 | 143篇 |
1992年 | 108篇 |
1991年 | 113篇 |
1990年 | 97篇 |
1989年 | 91篇 |
1988年 | 82篇 |
1987年 | 72篇 |
1986年 | 69篇 |
1985年 | 69篇 |
1984年 | 68篇 |
1983年 | 48篇 |
1982年 | 51篇 |
1981年 | 32篇 |
1980年 | 33篇 |
1979年 | 24篇 |
1978年 | 20篇 |
1977年 | 13篇 |
1976年 | 14篇 |
1974年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
酸碱对药所含酸碱性成分共煎形成复合物的结构研究 总被引:3,自引:0,他引:3
目的:研究乌头碱与甘草酸、乌头碱与大黄酸、小檗碱与大黄酸、麻黄碱与甘草酸在煎煮条件下形成的大分子复合物的结构.方法:采用X-射线光谱仪测定反应物及反应产物的结合能,用量子化学密度泛函理论计算各反应产物的基态电荷分布情况.结果:4对化合物中乌头碱与甘草酸、乌头碱与大黄酸、小檗碱与大黄酸的结合能在反应前后发生了改变,酸性成分的分子结构中特征性原子有较高正电荷,碱性成分的分子结构中特征性原子有较高负电荷.结论:4对化合物中乌头碱与甘草酸、乌头碱与大黄酸、小檗碱与大黄酸结合形成复合物.麻黄碱与甘草酸未形成复合物. 相似文献
32.
保守氨基酸残基在生物进化过程中具有较强的稳定性,一般不会发生太大的变化;生物信息学认为:氨基酸序列决定蛋白质结构,蛋白质结构决定蛋白质功能。因此,作者基于氨基酸的生化特性、几何特性和动态特性描述了一个新颖的算法去发现蛋白酶家族中的保守氨基酸残基,而保守氨基酸残基将对蛋白质的结构和功能的研究具有重要的意义。 相似文献
33.
34.
Principles and strategies of effective community participation 总被引:7,自引:5,他引:2
A framework is offered for understanding the conceptual basisand the strategic implications of community participation, inachieving Health for All goals. Special focus is given to themeaning, settings and levels of participation in official decision-makingstructures and at the community level. Questions such howis participation facilitated?, who participates?and what are the benefits and obstacles to participation?are geared primarily towards the needs of individuals who functionat the city level and expect practical strategic advice andguidance. The structure of the 1989 WHO Healthy Cities Symposiumwhich was devoted to community action was based on the frameworkand conceptual approach of this paper. 相似文献
35.
An advanced analysis of the mechanical properties of bone should include information about the microarchitecture of cancellous bone in addition to its density. It has recently been shown that high-resolution quantitative computed tomography and magnetic resonance imaging have the potential to assess such information in a noninvasive way in patients. Both techniques, however, lack sufficient spatial resolution to image the individual trabeculae with true precision. In this work, a new parameter, Ridge number density (RND), is introduced. RND is a measure for the trabecular number, which can be extracted directly from high-resolution three-dimensional (3D) images of patients. We applied the RND technique to a test group of nine healthy, postmenopausal women measured repetitively with a high-resolution 3D peripheral quantitative computed tomography (3D-pQCT) system with 165 × 165 × 165 μm3 voxel size. Simultaneously with the RND determination, the trabecular bone density (TBD) was also assessed in the same volume of interest. The examination site was the distal radius. The intersubject variability of the measured test group was 10.5% for RND and 26.3% for TBD. The root mean square error between first and second examinations (midterm reproducibility) was 1.6% and 1.1%, respectively. RND is determined independently from TBD and pertains to the structure of the cancellous bone. As such, it might add crucial information in cases where bone mass or bone density measurements alone give ambigous results. 相似文献
36.
Nicoletta Desideri Isabella Sestili Maria Luisa Stein Stefano Manarini Giuseppe Dell'Elba Chiara Cerletti 《Archiv der Pharmazie》1997,330(4):100-106
6-[(4-Quinolinyl)oxy]hexanoic acids and the corresponding esters were designed and synthesized as inhibitors of the production of arachidonic acid metabolites. The inhibitory activities were assayed in vitro by evaluation of serum leukotriene B4 and thromboxane B2 production. While all 6-[(4-quinolinyl)oxy]hexanoic acids and their esters proved to be inactive, the N-alkyl-4-quinolones, obtained as by-products in their synthesis, were found to be a new class of leukotriene biosynthesis inhibitors. 相似文献
37.
近几年,我国对以碘树脂进行供水终端消毒作了一些研究,并有商品投放市场。这类产品杀菌效果除与所填充的碘树脂本身杀菌性能有关外,与产品结构也有很大关系。结构不同,水中微生物通过净水器的时间(即消毒作用时间)也将不同。经推导:消毒作用时间与碘树脂柱长度、直径以及碘树脂颗粒大小、填充数量、出水量大小等有关。因此,在产品结构设计时,可通过调整上述各参数,获得最佳杀菌效果。本文通过对这类产品结构与杀菌效果关系的探讨,为有关企业及部门合理设计产品内部结构提供了新思路。 相似文献
38.
The electrodeposition of Ag on Pt(100)-(1 × 1) in perchlorate electrolyte was studied by means of time-resolved in situ scanning tunnelling microscopy (STM) and cyclic voltammetry. One monolayer of Ag is deposited underpotentially (upd) ca. 500 mV positive of the Ag+/Ag equilibrium potential. Several millivolts positive of the equilibrium potential, a second well defined upd layer forms. Its growth was observed to proceed via island formation and coalescence. This process occurs in two separate stages that manifest themselves in voltammetric peaks as well as in the STM images. 相似文献
39.
黄鹤群 《南通大学学报(哲学社会科学版)》2002,18(3):105-109
江海文化既有长江流域的源远流长 ,又有沿海岸线文化的博大精深 ,其构成源自水流文化的浸润、南北文化的影响、移民文化的交流、战地文化的积淀、艰苦创业的铸炼。文化是一个民族的根系 ,是一个民族的“身份证”。加强江海文化建设 ,把南通市建成文化大市 ,是我市新形势下的重要任务。为此 ,须理清江海文化建设的思路 ,找准切入点和突破口 ,在文化大市建设中显示文化投入的大气 ,展现独具特色的“灵气” ,焕发社会发展进步的朝气 ,奠定长期发展的底气。 相似文献
40.
SARAH VOOGHT BSc RGN ALISON RICHARDSON PhD MSc RGN 《European journal of cancer care》1996,5(4):217-224
Cancer patients are increasingly being cared for in the community. However, the role of the community oncology nurse specialist (CONS) remains a rare appointment in the United Kingdom. There is little research evidence to substantiate the view that this is a worthwhile and effective role. This study aimed to explore the role of one CONS using a qualitative case study approach. The sample consisted of the CONS, seven patients, no relatives and five community nurses. Semi-structured interviews were used to elicit the view of these participants. In addition, documents containing details of the CONS's work to date were reviewed. A number of the CONS's role components were identified by the different respondent groups. Five themes were identified within the data collected: functions of the CONS, communication between the CONS and other health care professionals, structural and organizational factors, characteristics of the service and benefits to patients and their families. Furthermore, all respondent groups were positive about the service offered by the CONS, and felt that the role was valuable. Some negative features were identified and these were concerned with organizational aspects of the service. The findings suggest the need for further research and evaluation in this area. 相似文献