全文获取类型
收费全文 | 1694474篇 |
免费 | 116673篇 |
国内免费 | 2842篇 |
专业分类
耳鼻咽喉 | 24461篇 |
儿科学 | 56084篇 |
妇产科学 | 49755篇 |
基础医学 | 247466篇 |
口腔科学 | 48145篇 |
临床医学 | 139685篇 |
内科学 | 336619篇 |
皮肤病学 | 37976篇 |
神经病学 | 131627篇 |
特种医学 | 63721篇 |
外国民族医学 | 434篇 |
外科学 | 257356篇 |
综合类 | 33891篇 |
现状与发展 | 2篇 |
一般理论 | 501篇 |
预防医学 | 128054篇 |
眼科学 | 38960篇 |
药学 | 127886篇 |
1篇 | |
中国医学 | 3814篇 |
肿瘤学 | 87551篇 |
出版年
2021年 | 13089篇 |
2019年 | 14082篇 |
2018年 | 20797篇 |
2017年 | 14909篇 |
2016年 | 16341篇 |
2015年 | 18557篇 |
2014年 | 25116篇 |
2013年 | 38304篇 |
2012年 | 53221篇 |
2011年 | 56639篇 |
2010年 | 33206篇 |
2009年 | 30184篇 |
2008年 | 52509篇 |
2007年 | 56861篇 |
2006年 | 56711篇 |
2005年 | 55386篇 |
2004年 | 52811篇 |
2003年 | 50970篇 |
2002年 | 49650篇 |
2001年 | 73390篇 |
2000年 | 75642篇 |
1999年 | 63837篇 |
1998年 | 17835篇 |
1997年 | 15804篇 |
1996年 | 14867篇 |
1995年 | 14873篇 |
1994年 | 14079篇 |
1992年 | 49391篇 |
1991年 | 48694篇 |
1990年 | 47900篇 |
1989年 | 46513篇 |
1988年 | 43175篇 |
1987年 | 42231篇 |
1986年 | 40280篇 |
1985年 | 38431篇 |
1984年 | 28564篇 |
1983年 | 24785篇 |
1982年 | 14710篇 |
1979年 | 27082篇 |
1978年 | 19050篇 |
1977年 | 16418篇 |
1976年 | 15518篇 |
1975年 | 17152篇 |
1974年 | 20262篇 |
1973年 | 19660篇 |
1972年 | 18594篇 |
1971年 | 17378篇 |
1970年 | 16323篇 |
1969年 | 15611篇 |
1968年 | 14652篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
A series of C(3)-cyclopropyl cephems and carbacephems has been prepared by palladium catalyzed addition of diazomethane to the corresponding C(3)-vinyl derivatives. The phenylglycyl cyclopropyl cephem derivatives exhibit better Gram-positive activity than cephalexin or cefaclor, while the aminothiazole oxime cyclopropyl cephem derivatives were not as active as the corresponding C(3)-vinyl cephems. 相似文献
992.
993.
Three cases of voluntary posterior instability of the shoulder are presented. They have all responded well to a program of electromyographic monitored biofeedback. This method offers a means of enhancing the results of nonoperative treatment. 相似文献
994.
995.
G Cavallini M Lanfredi M Lodi M Govoni M Pampolini 《Acta chirurgica Scandinavica》1987,153(3):179-184
Several studies were performed on polyester (Dacron) and polytetrafluoroethylene (PTFE) vascular substitute thrombogenicity. However, to date, the host-graft interactions have yet to be studied from an immunological point of view. For this reason, 4 classes of 10 patients each (Class 1: Dacron-+PTFE-grafted patients, Class 2: Dacron-, Class 3: PTFE-, and Class 4: controls) were submitted to a cellular immune-reactivity test: leukocyte adherence inhibition (LAI), in which leukocytes fail to adhere to glass on contact with a sensitizing antigen. The following blood cell populations were used: total leukocytes (PBL), mononuclear cells (MNC), T and B lymphocytes. This research demonstrated that a T cellular immune-reactivity towards Dacron and PTFE respectively occurs in Dacron- and PTFE-grafted patients, and that this reactivity is greater in the case of Dacron. More studies are required to determine the immuno-competent system role in fabric prosthesis patency. 相似文献
996.
Columnar metaplasia, dysplasia, and adenocarcinoma occurred in patches of bladder epithelium exposed to the fecal stream in rats. This suggests that such tumors complicating ureterosigmoidostomy may arise from ureteric epithelium, and that urine is not essential for their development. 相似文献
997.
Experience with the 'skew flap' below-knee amputation 总被引:3,自引:0,他引:3
A review of 353 lower limb amputations over the last 7 years has been performed to assess the results of the skew flap myoplastic below-knee amputation which was introduced in April 1983 because of reported advantages in terms of wound healing and earlier ambulation. Comparing the first 3 1/2 year period with the second, the total number of amputations decreased by 31 per cent. The number of above-knee amputations remained similar in the two periods (82,62), whilst the number of Gritti-Stokes amputations fell from 79 to 21 (0.001 greater than P greater than 0.01). The proportion of below-knee (BK) amputations increased from 50 (23.7 per cent) to 59 (41.5 per cent) (0.01 greater than P greater than 0.025). The groups were comparable in terms of previous vascular surgery and co-existing medical conditions. The time to full stump healing was significantly shorter in the skew flap group compared with the earlier Burgess type BK amputation (P = 0.001), and there was a trend to fewer stump failures in the skew flap group. We therefore feel that the skew flap amputation gives superior results to the Burgess BK amputation in terms of healing and a lower complication rate, allowing a higher proportion of BK amputations to be performed. A prospective randomized trial of the two techniques is in hand to determine the accuracy of this hypothesis. 相似文献
998.
999.
1000.
G Fran?ois C Mycinski L F Garnier B Charbonnier M Marchand L Guillou M Brochier 《Archives des maladies du coeur et des vaisseaux》1987,80(3):367-370
The authors report a case of massive haemolytic anaemia with acute mitral valve regurgitation and left cardiac failure, which occurred one year after surgical reconstruction of the mitral valve for rupture of smaller leaflet chordae. Anaemia, mitral regurgitation and cardiac failure disappeared after mitral valve replacement, using a Carpentier Edwards No. 29 valve. Haemolytic anaemia following mitral valve reconstruction is exceptional. It seems to be due to the suture material lying in a turbulent regurgitation stream when mitral incompetence develops again. 相似文献