全文获取类型
收费全文 | 11591篇 |
免费 | 656篇 |
国内免费 | 76篇 |
专业分类
耳鼻咽喉 | 48篇 |
儿科学 | 272篇 |
妇产科学 | 213篇 |
基础医学 | 1674篇 |
口腔科学 | 201篇 |
临床医学 | 899篇 |
内科学 | 3160篇 |
皮肤病学 | 92篇 |
神经病学 | 972篇 |
特种医学 | 599篇 |
外科学 | 1702篇 |
综合类 | 26篇 |
一般理论 | 4篇 |
预防医学 | 504篇 |
眼科学 | 111篇 |
药学 | 583篇 |
中国医学 | 40篇 |
肿瘤学 | 1223篇 |
出版年
2023年 | 61篇 |
2022年 | 161篇 |
2021年 | 265篇 |
2020年 | 137篇 |
2019年 | 201篇 |
2018年 | 273篇 |
2017年 | 211篇 |
2016年 | 278篇 |
2015年 | 277篇 |
2014年 | 399篇 |
2013年 | 525篇 |
2012年 | 850篇 |
2011年 | 885篇 |
2010年 | 510篇 |
2009年 | 442篇 |
2008年 | 773篇 |
2007年 | 794篇 |
2006年 | 777篇 |
2005年 | 774篇 |
2004年 | 695篇 |
2003年 | 716篇 |
2002年 | 632篇 |
2001年 | 138篇 |
2000年 | 132篇 |
1999年 | 134篇 |
1998年 | 152篇 |
1997年 | 95篇 |
1996年 | 88篇 |
1995年 | 83篇 |
1994年 | 71篇 |
1993年 | 48篇 |
1992年 | 49篇 |
1991年 | 71篇 |
1990年 | 43篇 |
1989年 | 39篇 |
1988年 | 51篇 |
1987年 | 34篇 |
1986年 | 33篇 |
1985年 | 29篇 |
1984年 | 42篇 |
1983年 | 30篇 |
1982年 | 35篇 |
1981年 | 31篇 |
1980年 | 23篇 |
1979年 | 18篇 |
1978年 | 14篇 |
1977年 | 14篇 |
1974年 | 18篇 |
1973年 | 16篇 |
1971年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
van Schie G Tanner C Snoeren P Samulski M Leifland K Wallis MG Karssemeijer N 《Physics in medicine and biology》2011,56(15):4715-4730
To improve cancer detection in mammography, breast examinations usually consist of two views per breast. In order to combine information from both views, corresponding regions in the views need to be matched. In 3D digital breast tomosynthesis (DBT), this may be a difficult and time-consuming task for radiologists, because many slices have to be inspected individually. For multiview computer-aided detection (CAD) systems, matching corresponding regions is an essential step that needs to be automated. In this study, we developed an automatic method to quickly estimate corresponding locations in ipsilateral tomosynthesis views by applying a spatial transformation. First we match a model of a compressed breast to the tomosynthesis view containing a point of interest. Then we estimate the location of the corresponding point in the ipsilateral view by assuming that this model was decompressed, rotated and compressed again. In this study, we use a relatively simple, elastically deformable sphere model to obtain an analytical solution for the transformation in a given DBT case. We investigate three different methods to match the compression model to the data by using automatic segmentation of the pectoral muscle, breast tissue and nipple. For validation, we annotated 208 landmarks in both views of a total of 146 imaged breasts of 109 different patients and applied our method to each location. The best results are obtained by using the centre of gravity of the breast to define the central axis of the model, around which the breast is assumed to rotate between views. Results show a median 3D distance between the actual location and the estimated location of 14.6 mm, a good starting point for a registration method or a feature-based local search method to link suspicious regions in a multiview CAD system. Approximately half of the estimated locations are at most one slice away from the actual location, which makes the method useful as a mammographic workstation tool for radiologists to interactively find corresponding locations in ipsilateral tomosynthesis views. 相似文献
992.
Doni A Paffoni A Nebuloni M Ragni G Pasqualini F Valentino S Bonetti S Mantovani A Somigliana E Garlanda C 《International journal of andrology》2009,32(3):255-264
The long pentraxin 3 (PTX3) is a multifunctional soluble pattern recognition receptor, involved in several processes ranging from innate resistance and inflammation to clearance of apoptotic cells and organization of hyaluronic acid-rich extracellular matrices. PTX3 is also a novel marker in several pathological conditions of infectious, inflammatory, or autoimmune origin. This study was designed to assess whether PTX3 is expressed in the male reproductive tract and whether PTX3 interacts with human spermatozoa influencing their function. Here we show for the first time by immunohistochemistry that PTX3 is expressed in the male genital tract in perivascular connective tissue, in endothelial cells, in the interstitium, and in the cytoplasm of prostatic epithelial glandular cells; PTX3 was detectable in seminal plasma in variable levels, which correlated with the percentage of normal spermatozoa. Moreover, PTX3 binds to spermatozoa, in particular with immotile cells, localizing in the neck and in the subacrosomial region. Finally, recombinant PTX3 did not interfere with sperm motility. 相似文献
993.
Donat SM Shabsigh A Savage C Cronin AM Bochner BH Dalbagni G Herr HW Milowsky MI 《European urology》2009,55(1):177-185
994.
995.
996.
997.
998.
999.
1000.
Molfino Alessio Kushta Irma Tommasi Valentina Rossi Fanelli Filippo Muscaritoli Maurizio 《Journal of neurology》2009,256(6):1015-1016
Journal of Neurology - 相似文献