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   2764篇
  免费   178篇
  国内免费   13篇
耳鼻咽喉   83篇
儿科学   275篇
妇产科学   33篇
基础医学   262篇
口腔科学   136篇
临床医学   263篇
内科学   476篇
皮肤病学   50篇
神经病学   109篇
特种医学   363篇
外科学   282篇
综合类   26篇
预防医学   173篇
眼科学   18篇
药学   85篇
中国医学   2篇
肿瘤学   319篇
  2022年   14篇
  2021年   55篇
  2020年   24篇
  2019年   35篇
  2018年   51篇
  2017年   32篇
  2016年   39篇
  2015年   61篇
  2014年   71篇
  2013年   90篇
  2012年   123篇
  2011年   102篇
  2010年   85篇
  2009年   80篇
  2008年   80篇
  2007年   103篇
  2006年   89篇
  2005年   102篇
  2004年   93篇
  2003年   76篇
  2002年   69篇
  2001年   60篇
  2000年   51篇
  1999年   73篇
  1998年   107篇
  1997年   86篇
  1996年   86篇
  1995年   59篇
  1994年   60篇
  1993年   70篇
  1992年   55篇
  1991年   41篇
  1990年   56篇
  1989年   69篇
  1988年   48篇
  1987年   59篇
  1986年   46篇
  1985年   52篇
  1984年   37篇
  1983年   33篇
  1982年   38篇
  1981年   36篇
  1980年   38篇
  1979年   14篇
  1978年   28篇
  1977年   33篇
  1976年   31篇
  1975年   19篇
  1973年   15篇
  1972年   17篇
排序方式: 共有2955条查询结果,搜索用时 15 毫秒
1.
Needle-localized breast biopsy: why do we fail?   总被引:10,自引:0,他引:10  
Jackman  RJ; Marzoni  FA  Jr 《Radiology》1997,204(3):677
  相似文献   
2.
3.
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   
4.
Occupational disease surveillance data sources, 1985.   总被引:1,自引:1,他引:0       下载免费PDF全文
Health department epidemiologists in 50 states, New York City, and the District of Columbia were surveyed in 1985 about seven potential data sources for occupational disease surveillance. Reported sources of occupational disease data were: automated workers' compensation claims (63 per cent of the 52 respondents); provider reports (62 per cent); death certificates with occupation or industry (60 per cent); cancer registries with occupational histories (35 per cent); birth certificates with parent's occupation (27 per cent); non-cancer disease registries (13 per cent); and hospital or insurance records (8 per cent).  相似文献   
5.
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   
6.
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