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   151313篇
  免费   31260篇
  国内免费   2403篇
耳鼻咽喉   5158篇
儿科学   5401篇
妇产科学   2380篇
基础医学   3049篇
口腔科学   1493篇
临床医学   26628篇
内科学   47530篇
皮肤病学   7427篇
神经病学   14903篇
特种医学   6422篇
外科学   41108篇
综合类   255篇
现状与发展   72篇
预防医学   6997篇
眼科学   3421篇
药学   953篇
中国医学   12篇
肿瘤学   11767篇
  2024年   684篇
  2023年   4788篇
  2022年   1191篇
  2021年   3097篇
  2020年   6024篇
  2019年   2161篇
  2018年   7370篇
  2017年   7342篇
  2016年   8415篇
  2015年   8405篇
  2014年   15480篇
  2013年   15593篇
  2012年   5456篇
  2011年   5470篇
  2010年   10350篇
  2009年   14240篇
  2008年   5779篇
  2007年   4008篇
  2006年   6468篇
  2005年   3764篇
  2004年   3006篇
  2003年   2039篇
  2002年   2091篇
  2001年   3854篇
  2000年   3047篇
  1999年   3263篇
  1998年   3650篇
  1997年   3470篇
  1996年   3366篇
  1995年   3217篇
  1994年   1954篇
  1993年   1569篇
  1992年   1412篇
  1991年   1439篇
  1990年   1082篇
  1989年   1204篇
  1988年   1031篇
  1987年   861篇
  1986年   904篇
  1985年   748篇
  1984年   567篇
  1983年   536篇
  1982年   518篇
  1981年   406篇
  1980年   367篇
  1979年   312篇
  1978年   336篇
  1977年   400篇
  1975年   282篇
  1972年   304篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
993.
994.
Colorectal cancer is one of the most common malignancies in developed countries. Although guaiac-based fecal occult blood tests have proven their efficacy for screening, they have major drawbacks. Immunochemical fecal occult blood tests are theoretically superior as they can detect very small amounts of hemoglobin, and they are specific to human hemoglobin. Recently many different immunochemical tests have been marketed, with variations in hemoglobin detection limit, mechanism of action, sample collection method, and test development. Molecular tests represent an alternative to fecal blood tests, which have been designed to detect certain fecal DNA mutations, or aberrant gene methylation (either hyper-or hypomethylation). In this review, we discuss a selection of the most significant studies published in the last 3 years regarding noninvasive tools for colorectal cancer screening.  相似文献   
995.
996.
997.
998.
999.
Vleggaar Danny  MD 《Dermatologic surgery》2005,31(S4):1511-1518
Background. Polymers of lactic acid have been widely used for many years in different types of medical devices, such as resorbable sutures, intrabone implants, and soft tissue implants. Injectable poly-l-lactic acid (PLLA; Sculptra), a synthetic, biodegradable polymer, has gained widespread popularity in Europe for the treatment of facial changes associated with aging.
Objective. To provide background information on injectable PLLA and to describe clinical experience with its use in Europe for facial volume enhancement.
Methods. Technique varies with site of injection. Generally, the product is implanted subcutaneously or intradermally in a series of treatments. No allergy testing is required.
Results. Based on experience in more than 2,500 patients, injectable PLLA has been used successfully for the correction of nasolabial folds, mid- and lower facial volume loss, jawline laxity, and other signs of facial aging. Correction lasts for 18 to 24 months in most patients.
Conclusions. Injectable PLLA treatment provides an excellent and prolonged correction of a variety of facial wrinkles, depressions, and laxity with a minimally invasive procedure that does not require allergy testing or a recovery period.  相似文献   
1000.
BACKGROUND: Preservation of hair follicle units for the purpose of delayed transplant will help us graft thousands of hair grafts at one session, even in a clinic with fewer assistants and less equipment. OBJECTIVE: This study was undertaken to evaluate and compare the viability of hair follicle units preserved at 0 and 4 degrees C for various periods. MATERIALS AND METHODS: Cell cultures and transplant of hair follicle units into athymic mice were performed. RESULTS: Outer root sheath cells could be cultivated in 96% (0 degrees C group) and 92% (4 degrees C group) of the hair follicles after 24 hours of preservation, whereas 85% (0 degrees C group) and 79% (4 degrees C group) of the follicles implanted into the mice regrew well after the same period of preservation. Then, in both the 0 degrees C and the 4 degrees C group, these rates decreased significantly with length of preservation in cell cultures and mice transplant; however, 0 degrees C seems better than 4 degrees C for preservation of grafts (p<.05). CONCLUSION: Grafts are better preserved at 0 degrees C instead of 4 degrees C. When delayed transplant is an option, it should be completed within 24 hours and no later than 48 hours.  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