全文获取类型
收费全文 | 1603862篇 |
免费 | 146681篇 |
国内免费 | 1431篇 |
出版年
2021年 | 18249篇 |
2019年 | 16230篇 |
2018年 | 19557篇 |
2017年 | 18357篇 |
2016年 | 29266篇 |
2015年 | 42818篇 |
2014年 | 50927篇 |
2013年 | 77027篇 |
2012年 | 46453篇 |
2011年 | 37833篇 |
2010年 | 47460篇 |
2009年 | 47638篇 |
2008年 | 34666篇 |
2007年 | 33855篇 |
2006年 | 36553篇 |
2005年 | 37870篇 |
2004年 | 36698篇 |
2003年 | 34044篇 |
2002年 | 31962篇 |
2001年 | 47783篇 |
2000年 | 45184篇 |
1999年 | 41870篇 |
1998年 | 27123篇 |
1997年 | 26831篇 |
1996年 | 26136篇 |
1995年 | 24284篇 |
1994年 | 23911篇 |
1993年 | 23189篇 |
1992年 | 35464篇 |
1991年 | 34071篇 |
1990年 | 32600篇 |
1989年 | 33039篇 |
1988年 | 30217篇 |
1987年 | 29001篇 |
1986年 | 27308篇 |
1985年 | 28805篇 |
1984年 | 27073篇 |
1983年 | 23928篇 |
1982年 | 22679篇 |
1981年 | 21680篇 |
1980年 | 20275篇 |
1979年 | 23221篇 |
1978年 | 20912篇 |
1977年 | 19644篇 |
1976年 | 18915篇 |
1975年 | 19012篇 |
1974年 | 19856篇 |
1973年 | 20108篇 |
1972年 | 17353篇 |
1971年 | 15765篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
981.
982.
983.
984.
Ferredoxin from Bacillus polymyxa 总被引:5,自引:0,他引:5
Y I Shethna N A Stombaugh R H Burris 《Biochemical and biophysical research communications》1971,42(6):1108-1116
985.
986.
Immunoglobulin-containing cells in lungs of hamsters infected with Mycoplasma pneumoniae 总被引:17,自引:0,他引:17
G W Fernald W A Clyde J Bienenstock 《Journal of immunology (Baltimore, Md. : 1950)》1972,108(5):1400-1408
987.
Five cases of coincident salmonellosis and ulcerative colitis are described. In three the diagnostic combination was recognized late. If corticosteroid therapy is given for the colitis once the combination is recognized, then simultaneous systemic antibiotic cover is advisable. One of the five patients died during corticosteroid therapy alone with salmonella septicaemia due to a usually non-invasive organism. 相似文献
988.
A. J. Edwards J. D. Hamilton W. D. Nichol G. W. Taylor A. M. Dawson 《BMJ (Clinical research ed.)》1970,1(5692):342-345
Seven patients with “coeliac axis compression syndrome” are reported. Five were treated surgically, but only two did well. A survey of 200 healthy adults showed epigastric bruits in 6·5%; only one of these had dyspepsia, though dyspepsia was present in 12·5% overall.Caution is urged in attributing a causal relationship between coeliac axis compression and pain and in proceeding to arteriography when compression is suspected on clinical grounds. 相似文献
989.
From experience in the Northampton/Kettering area 9 to 10% of all patients in a general hospital requiring care in an intensive therapy unit were aged 12 years or under. Fifty-nine children were admitted to the intensive therapy unit of Northampton General Hospital between May 1967 and August 1969. Of these, 22 had been injured in road traffic accidents, five were surgical emergencies, five had meningitis, four status epilepticus, and four respiratory infections.All of the 30 families interviewed were in favour of their child being admitted to the unit, and none considered that the experience had had any lasting adverse psychological effect on the child. It is suggested that certain carefully selected child patients do benefit from the facilities of an intensive therapy unit, and for this reason such units must be designed, equipped, and staffed with this in mind. 相似文献
990.
P. Marion Handford 《Journal of applied microbiology》1974,37(4):559-570
S ummary . This paper describes the development and use of a selective diagnostic medium for the detection and enumeration of Clostridium perfringens in foods. The medium gives higher counts of Cl. perfringens and fewer false positives than existing media. 相似文献