全文获取类型
收费全文 | 1794735篇 |
免费 | 140139篇 |
国内免费 | 6859篇 |
专业分类
耳鼻咽喉 | 23122篇 |
儿科学 | 57706篇 |
妇产科学 | 48161篇 |
基础医学 | 257805篇 |
口腔科学 | 49516篇 |
临床医学 | 161245篇 |
内科学 | 359727篇 |
皮肤病学 | 42693篇 |
神经病学 | 143259篇 |
特种医学 | 71925篇 |
外国民族医学 | 332篇 |
外科学 | 278806篇 |
综合类 | 38781篇 |
现状与发展 | 2篇 |
一般理论 | 589篇 |
预防医学 | 141514篇 |
眼科学 | 39077篇 |
药学 | 129302篇 |
5篇 | |
中国医学 | 3152篇 |
肿瘤学 | 95014篇 |
出版年
2018年 | 18464篇 |
2016年 | 16927篇 |
2015年 | 18930篇 |
2014年 | 26234篇 |
2013年 | 39182篇 |
2012年 | 49417篇 |
2011年 | 53353篇 |
2010年 | 32736篇 |
2009年 | 31555篇 |
2008年 | 49633篇 |
2007年 | 52926篇 |
2006年 | 53940篇 |
2005年 | 51921篇 |
2004年 | 49836篇 |
2003年 | 48261篇 |
2002年 | 46146篇 |
2001年 | 84694篇 |
2000年 | 87356篇 |
1999年 | 72749篇 |
1998年 | 21359篇 |
1997年 | 18956篇 |
1996年 | 20073篇 |
1995年 | 19933篇 |
1994年 | 18491篇 |
1993年 | 17517篇 |
1992年 | 59614篇 |
1991年 | 58946篇 |
1990年 | 57188篇 |
1989年 | 54771篇 |
1988年 | 50611篇 |
1987年 | 49830篇 |
1986年 | 46968篇 |
1985年 | 45323篇 |
1984年 | 34324篇 |
1983年 | 29025篇 |
1982年 | 17635篇 |
1981年 | 16003篇 |
1980年 | 15027篇 |
1979年 | 31447篇 |
1978年 | 22852篇 |
1977年 | 19297篇 |
1976年 | 17989篇 |
1975年 | 19250篇 |
1974年 | 22702篇 |
1973年 | 21577篇 |
1972年 | 20303篇 |
1971年 | 18931篇 |
1970年 | 17356篇 |
1969年 | 16358篇 |
1968年 | 15286篇 |
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
881.
882.
Apramycin and gentamicin resistance in Escherichia coli and salmonellas isolated from farm animals 总被引:2,自引:0,他引:2
Since the aminoglycoside antibiotic apramycin was licensed for veterinary use in 1980, all isolates of Escherichia coli and salmonellas received at the Central Veterinary Laboratory have been monitored for resistance to apramycin and the related antibiotic gentamicin. During the period 1982-4, the incidence of resistance in E. coli to apramycin increased from 0.6% in 1982 to 2.6% in 1984. In salmonellas the incidence of resistance to apramycin increased from 0.1% in 1982 to 1.4% in 1984. Resistance to both apramycin and gentamicin was detected in six different salmonella serotypes, although an isolate of Salmonella thompson from poultry was resistant to gentamicin but not apramycin. Most of the cultures were isolated from pigs, although the incidence of apramycin resistance in S. typhimurium (DT 204C) from calves has shown a recent dramatic increase. All the isolates with one exception produced the enzyme aminoglycoside 3-N-acetyltransferase IV (ACC(3)IV). The resistance was transferable by conjugation in most of the strains examined, and the plasmids specifying the resistance have been found to belong to a number of different incompatibility groups. Plasmids from three E. coli strains were compatible with all the reference plasmids and belonged to a previously undescribed group which was investigated further. It is suggested that bacteria from humans should be examined for resistance to apramycin and gentamicin to determine the possibility of the antibiotic-resistance bacteria, and their genes, spreading from animals to humans. 相似文献
883.
884.
M M O'Kane P A King H D Edmondson 《International journal of oral and maxillofacial surgery》1986,15(4):422-424
Button wiring has been used as an alternative to eyelet wiring in the Department of Oral and Dental Surgery of Birmingham General Hospital since 1977. This clinical update reviews 65 patients with mandibular fractures in which button wires were utilised in their treatment. 相似文献
885.
886.
J D Fortenberry R F Hill 《Journal of adolescent health care : official publication of the Society for Adolescent Medicine》1986,7(3):202-204
Incestuous child sexual abuse has received increasing attention recently, but relatively little attention has focused on the multigenerational dimensions of this problem. The case presented places incest into a multigenerational context and demonstrates how quickly family relationships may become eroticized in an uncommon form: between sisters. 相似文献
887.
Current status of research activity in American child and adolescent psychiatry: Part I 总被引:1,自引:0,他引:1
T Shapiro D Mrazek H A Pincus 《Journal of the American Academy of Child and Adolescent Psychiatry》1991,30(3):443-448
A survey of research activity of American academic child psychiatrists was completed in February, 1989. The survey demonstrated an increase in research activity since the 1983 report in the Current Status of Child Psychiatry. A definition of a researcher was derived from a study of internists and general psychiatrists and applied to the 488 respondents (78.5% of sample), and it was found that males outnumber females and that researchers contribute significantly more to the literature and education than nonresearchers. Early research exposure and mentoring are important influences on a research career. Recommendations by researchers for future training of researchers are presented. Periodic surveys are encouraged. 相似文献
888.
F Biering-S?rensen J Lehmann Knudsen A Schmidt A Bundgaard I Christensen 《Paraplegia》1991,29(2):113-119
Ten tetraplegics, 8 males and 2 females, with a median age of 32 years participated in a scheduled 6 weeks training programme with a respiratory muscle training mouth-nose-mask (RMT-mask) with a fixed expiratory and an increasing inspiratory resistance set by the tetraplegic in accordance to his/her increasing ability during the training period. During the 6 weeks the tetraplegics required to use the RMT-mask for 15 minutes three times a day. Before and after each training session they measured peak flow (PEF). Lung volumes, ventilatory and diffusion capacity were measured before and after the 6 weeks training period. The training resulted only in a significant change in the PEF, which increased with 11% from 371 l/min before to 412 l/min in average after the 6 weeks of training (p less than 0.025). This statistically significant increase was confirmed by the measurements of PEF performed by the tetraplegics themselves during the training period. In addition there was an increase in PEF from before to immediately after each 15 minutes training session, this trend reached statistically significance (p less than 0.025) in the third '2 weeks period'. These results might indicate a possibility of improving the tetraplegics ability to cough by use of a simple RMT-mask, which in turn might prevent certain lung complications including pneumonia, and atelectasia. 相似文献
889.
D Hadley 《Rhode Island dental journal》1986,19(4):6-7, 9-10, 12-6
890.
W D Lovan R A Weaver R J Lentz J K Goodrum B F Withers 《Aviation, space, and environmental medicine》1986,57(4):370-375
The Naval Special Board of Flight Surgeons was established in 1956 for the evaluation of Navy, Marine Corps, and Coast Guard problem aeromedical cases. This paper examines a sample 248 of these cases for the period of 1974-83 with respect to the characteristics of those referred, their referral diagnostic category, and the recommendation of the Special Board regarding return to a flying status. Those cases with a referral diagnostic category of ENT and Ophthalmology were less likely to be returned to flight status. Older, more senior pilots, and pilots with more total flight time were less likely to be returned to unrestricted flying than were their younger, more junior, and less experienced counterparts. Otherwise, no significant difference in outcome based on age, rank, marital status, branch of service, specialty, or flight hours was detected. Overall, 61% of those evaluated by the SBFS were returned to flight status. 相似文献