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   2583篇
  免费   182篇
  国内免费   30篇
耳鼻咽喉   81篇
儿科学   250篇
妇产科学   35篇
基础医学   244篇
口腔科学   159篇
临床医学   244篇
内科学   429篇
皮肤病学   44篇
神经病学   101篇
特种医学   311篇
外科学   271篇
综合类   34篇
预防医学   176篇
眼科学   16篇
药学   102篇
中国医学   2篇
肿瘤学   296篇
  2022年   16篇
  2021年   53篇
  2020年   21篇
  2019年   36篇
  2018年   53篇
  2017年   36篇
  2016年   39篇
  2015年   59篇
  2014年   71篇
  2013年   77篇
  2012年   119篇
  2011年   104篇
  2010年   89篇
  2009年   75篇
  2008年   78篇
  2007年   101篇
  2006年   93篇
  2005年   94篇
  2004年   83篇
  2003年   85篇
  2002年   69篇
  2001年   64篇
  2000年   53篇
  1999年   66篇
  1998年   72篇
  1997年   88篇
  1996年   88篇
  1995年   54篇
  1994年   44篇
  1993年   52篇
  1992年   61篇
  1991年   45篇
  1990年   62篇
  1989年   69篇
  1988年   63篇
  1987年   51篇
  1986年   53篇
  1985年   54篇
  1984年   22篇
  1983年   27篇
  1982年   28篇
  1981年   23篇
  1980年   22篇
  1978年   16篇
  1977年   28篇
  1976年   21篇
  1975年   12篇
  1974年   11篇
  1973年   15篇
  1972年   17篇
排序方式: 共有2795条查询结果,搜索用时 0 毫秒
1.
2.
Sonoelasticity imaging of prostate cancer: in vitro results   总被引:2,自引:0,他引:2  
  相似文献   
3.
4.
BACKGROUND: Endovascular radiofrequency obliteration has been used since 1998 as an alternative to conventional vein stripping surgery for elimination of saphenous vein insufficiency. OBJECTIVE: To demonstrate the long-term efficacy of this treatment modality. METHODS: Data were prospectively collected in a multicenter ongoing registry. Only great saphenous vein above-knee treatments were included in this study. Eight hundred ninety patients (1,078 limbs) were treated prior to November 2003 at 32 centers. Clinical and duplex ultrasound follow-up was performed at 1 week, 6 months, and 1, 2, 3, and 4 years. RESULTS: Among 1,078 limbs treated, 858 were available for follow-up within 1 week, 446 at 6 months, 384 at 1 year, 210 at 2 years, 114 at 3 years, and 98 at 4 years. The vein occlusion rates were 91.0%, 88.8%, 86.2%, 84.2%, and 88.8%, respectively; the reflux-free rates were 91.0%, 89.3%, 86.2%, 86.0%, and 85.7%, respectively; and the varicose vein recurrence rates were 7.2%, 13.5%, 17.1%, 14.0%, and 21.4%, respectively, at each follow-up time point at 6 months, and 1, 2, 3, and 4 years. Patient symptom improvement persisted over 4 years. CONCLUSIONS: Endovascular temperature-controlled radiofrequency obliteration of saphenous vein reflux exhibits an enduring treatment efficacy clinically, anatomically, and hemodynamically up to 4 years following treatment.  相似文献   
5.
6.
The effect of specific glycosaminoglycan-hydrolyzing enzymes on the ruthenium red staining of pig spermatozoa was studied. Washed spermatozoa were incubated at 35 degrees C in buffer or with neuraminidase 0.5 units/ml, heparinase 0.2 mg/ml, or chondroitinase ABC 2.0 units/ml. After incubation sperm cells were washed, stained with ruthenium red and studied under the electron microscope. Anionic sites in the surface of untreated spermatozoa follow regularly the plasma membrane, but present are numerous processes constituting what has been defined as the glycocalyx. Neuraminidase did not affect the distribution of ruthenium red on the surface of the spermatozoa, but eliminated almost completely the processes of the glycocalyx. Heparinase caused loss of the ruthenium red-stained sites on the membrane surface of pig spermatozoa with less influence on the dense processes of the glycocalyx. A similar loss of ruthenium red-stained sites was observed with nitrous acid treatment. A striking effect of treatment with chondroitinase ABC was the production of a typical acrosome reaction.  相似文献   
7.
8.
9.
10.
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