全文获取类型
收费全文 | 2398篇 |
免费 | 0篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 4篇 |
建筑科学 | 1篇 |
轻工业 | 2篇 |
石油天然气 | 2篇 |
无线电 | 2篇 |
一般工业技术 | 10篇 |
冶金工业 | 2374篇 |
自动化技术 | 1篇 |
出版年
2021年 | 1篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2009年 | 3篇 |
2008年 | 2篇 |
2006年 | 2篇 |
2005年 | 1篇 |
2003年 | 3篇 |
2002年 | 3篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 76篇 |
1998年 | 696篇 |
1997年 | 405篇 |
1996年 | 249篇 |
1995年 | 142篇 |
1994年 | 146篇 |
1993年 | 148篇 |
1992年 | 30篇 |
1991年 | 32篇 |
1990年 | 40篇 |
1989年 | 66篇 |
1988年 | 39篇 |
1987年 | 36篇 |
1986年 | 26篇 |
1985年 | 23篇 |
1983年 | 3篇 |
1982年 | 11篇 |
1981年 | 13篇 |
1980年 | 18篇 |
1979年 | 2篇 |
1978年 | 7篇 |
1977年 | 54篇 |
1976年 | 113篇 |
1975年 | 1篇 |
1955年 | 2篇 |
排序方式: 共有2398条查询结果,搜索用时 9 毫秒
141.
142.
143.
144.
145.
146.
147.
Drug use is related to the environment in which drug users live. Using 32 economic, housing, crime, and health variables for 1990 census tracts in Houston, Texas, this study found four identifiable factors: social disorganization, economic success, threat of violence, and chronic disease. Narcotic offenses loaded strongly on one and weakly on two of the factors; this variable did not load on the economic success factor. These results suggest that a textured look at drug use environments finds them to be multidimensional. Urban dwellers must deal with the independent effects of social disorganization, economic conditions, chronic disease, and violence. 相似文献
148.
149.
It is common to examine the cerebrospinal fluid in untreated or inadequately treated asymptomatic patients with a reactive serum fluorescent treponemal antibody absorption (FTA-ABS) test before initiating antibiotic therapy for syphilis. This prospective study evaluated the usefulness of such examination. Four hundred thirty-two patients over 40 years old, reporting for annual physical examination, had a serum FTA-ABS test. Thirty-seven (8.6%) patients and 2 of 4 spouses were reactive repeatedly. Of the 39 patients with reactive tests, 7 had a history of penicillin therapy for syphilis, 5 had received heavy metal therapy, and 27 had no history of syphilis. These 39 patients had a neurological examination, serum VDRL, Treponema pallidum immobilization (TPI), and repeat FTA-ABS tests by two other laboratories. The TPI test was reactive in 30 (77%). Four had nonspecific neurological signs. Routine CSF examination (cells, total protein, VDRL, glucose, IgG%) on 30 patients with a history of inadequate treatment had a low diagnostic yield. Two patients had an unexplained total protein elevation (57 and 61 mg/dl) and 1 had a mildly increased IgG% (15%). All cell counts, VDRL tests, and glucose levels were normal. Agarose electrophoresis demonstrated one or more CSF immunoglobulin bands in 10 (36%) of 28 patients, possibly representing an immunological marker of past or latent central nervous system infection. 相似文献
150.
WJ Kalk DC Cominos A van der Walt AJ van Rooyen 《Canadian Metallurgical Quarterly》1977,52(12):485-486
Furosemide, in combination with breast binding and milk fluid restriction, seems to inhibit postpartum lactation effectively, but has no effect in reducing serum prolactin levels. Inhibition of milk secretion must therefore be mediated by other mechanisms. 相似文献