全文获取类型
收费全文 | 4582篇 |
免费 | 1篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 14篇 |
金属工艺 | 10篇 |
机械仪表 | 1篇 |
建筑科学 | 3篇 |
能源动力 | 1篇 |
轻工业 | 22篇 |
无线电 | 1篇 |
一般工业技术 | 14篇 |
冶金工业 | 4507篇 |
原子能技术 | 2篇 |
自动化技术 | 7篇 |
出版年
2017年 | 1篇 |
2016年 | 3篇 |
2013年 | 9篇 |
2012年 | 2篇 |
2011年 | 9篇 |
2010年 | 1篇 |
2009年 | 2篇 |
2008年 | 4篇 |
2007年 | 1篇 |
2006年 | 2篇 |
2005年 | 5篇 |
2004年 | 3篇 |
2003年 | 8篇 |
2002年 | 4篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1999年 | 152篇 |
1998年 | 1359篇 |
1997年 | 737篇 |
1996年 | 508篇 |
1995年 | 265篇 |
1994年 | 238篇 |
1993年 | 252篇 |
1992年 | 35篇 |
1991年 | 73篇 |
1990年 | 60篇 |
1989年 | 85篇 |
1988年 | 71篇 |
1987年 | 64篇 |
1986年 | 68篇 |
1985年 | 53篇 |
1984年 | 1篇 |
1983年 | 4篇 |
1982年 | 16篇 |
1981年 | 27篇 |
1980年 | 48篇 |
1979年 | 2篇 |
1978年 | 10篇 |
1977年 | 121篇 |
1976年 | 265篇 |
1975年 | 5篇 |
1971年 | 1篇 |
1969年 | 1篇 |
1967年 | 1篇 |
1955年 | 3篇 |
排序方式: 共有4584条查询结果,搜索用时 15 毫秒
31.
32.
33.
Endoscopic retrograde cholangiopancreatography is a new and valuable technique in the diagnosis of jaundice, pancreatic disease and obscure upper abdominal pain. Endoscopic sphincterotomy of the sphincter of Oddi and the extraction of stones from the common bile duct are an extension of this procedure already in use in several high-volume centres. Cannulation of the bile ducts and pancreatic ducts in tests of secretion and cytology will become increasingly common applications of the technique. In order to provide dependability and cost-effectiveness, specialists in this procedure must maintain a high volume, necessarily limiting it to a few practitioners. Use of a trained endoscopic technician, a radiologist trained in endoscopy, or an endoscopist trained in fluoroscopy and spot-filming may decrease the manpower costs of this procedure. 相似文献
34.
In the new agent 3-(5-tetrazolyl)penam, hereafter referred to as CP-35,587, the carboxyl function at C3 in the penicillin nucleus has been replaced with the 5-tetrazolyl moiety. Marked changes in spectrum and resistance to gram-negative beta-lactamases, particularly with regard to Klebsiella pneumoniae isolates, were conferred by this modification. The anti-Klebsiella activity clearly distinguishes the antibacterial spectrum of CP-35,587 from any known broad-spectrum penicillin. Compared to orally active cephalosporins, the spectrum advantage of CP-35,587 encompasses Enterobacter, Serratia marcescens, Citrobacter, Providencia, Haemophilus influenzae, and Streptococcus faecalis, both in vitro and in murine infections produced by many of the above-named microorganisms. Thus, CP-35,587 combines and extends the antibacterial activity of broad-spectrum penicillins and orally active cephalosporins. 相似文献
35.
A dye reduction method was developed for estimating total aerobic and/or psychrotrophic bacterial counts in ground beef. The method is based on color changes in indicator disks placed on the meat surface. 相似文献
36.
A procedure is described for extracting doxepin, a tricyclic antidepressant, from plasma and subsequently measuring its concentration by GLC. The developed technique permits the resolution and quantitative determination of the cis- and trans-isomers of doxepin as well as its desmethyl metabolite. The method allows precise, reliable measurement of the drug and one of its metabolities in concentrations as low as 10 ng/ml of plasma. 相似文献
37.
Mycobacterium avium complex-serotype 6 was isolated in pure culture on blood agar plates from inocula taken from the heart blood, lungs, liver, kidneys, and spleen of a naturally infected captive female opossum (Didelphis marsupialis virginiana). Repeat cultures from stored tissues and transfer of colonies from original blood agar plates revealed that the mycobacterium grew on tryptose, brilliant green, eosin-methylene blue. Sabouraud glucose, and mycobiotic agar plates and in Fletcher leptospira medium. The cultural, biochemical, and serological characteristics of the test isolate were compared with other mycobacteria. This is the first report to describe the primary isolation of a serotype from the M. avium complex from an animal species on blood agar or in Fletcher broth. In addition, this is the second documented report describing the isolation and identification of a mycobacterial species from the American opossum. 相似文献
38.
JE Gustafson 《Canadian Metallurgical Quarterly》1976,5(3):184-185
Supracondylar fractures of the femor or humerus and fractures of the radius, ulna, tibia or fibula, plus crush injuries of the limbs, most likely should not be manipulated in the field because of the potential for traumatizing adjacent nerves, veins and arteries. An emergency splinting system that allows immobilization without repositioning has been developed. Furthermore, fractures in or about the elbow, wrist, knee, or ankle should not be subjected to reduction in the field, unless there are compelling reasons to justify the risk of producing significant additional trauma. Conservative immobilization without repositioning may yield a more positive prognosis for the patient. 相似文献
39.
40.