全文获取类型
收费全文 | 426篇 |
免费 | 7篇 |
学科分类
工业技术 | 433篇 |
出版年
2022年 | 2篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 5篇 |
2017年 | 5篇 |
2016年 | 3篇 |
2015年 | 4篇 |
2014年 | 2篇 |
2013年 | 18篇 |
2012年 | 9篇 |
2011年 | 12篇 |
2010年 | 10篇 |
2009年 | 5篇 |
2008年 | 11篇 |
2007年 | 14篇 |
2006年 | 8篇 |
2005年 | 14篇 |
2004年 | 4篇 |
2003年 | 12篇 |
2002年 | 8篇 |
2001年 | 5篇 |
2000年 | 7篇 |
1999年 | 9篇 |
1998年 | 58篇 |
1997年 | 30篇 |
1996年 | 21篇 |
1995年 | 14篇 |
1994年 | 15篇 |
1993年 | 17篇 |
1991年 | 5篇 |
1990年 | 8篇 |
1989年 | 6篇 |
1988年 | 2篇 |
1987年 | 6篇 |
1986年 | 10篇 |
1985年 | 6篇 |
1984年 | 7篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1981年 | 9篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1976年 | 8篇 |
1974年 | 4篇 |
1973年 | 3篇 |
1971年 | 2篇 |
1954年 | 1篇 |
1930年 | 1篇 |
排序方式: 共有433条查询结果,搜索用时 296 毫秒
421.
Hazardous lead release from glazed dinnerware: a cautionary note 总被引:1,自引:0,他引:1
Numerous pieces of contemporary glazed pottery dinnerware made in Italy and Mexico have been shown to release excessive amounts of lead, greater than 1000 ppm in several instances. Extended use with frequent scouring increased the lead release. This pottery, manufactured under obsolete conditions, may be imported into the United States by tourists, retail merchants and immigrants, and used for daily cooking and storage of food and beverages. Our findings demonstrate a potentially widespread health hazard both in the countries of origin of the pottery and the countries of importation. 相似文献
422.
Levin Joel R.; Peterson Penelope L.; Pressley Michael; Yussen Steven R.; Berman Linda S.; Bird J. E.; Carnahan Richard S.; Farley Frank H.; Germano Mark C.; Hiebert Elfrieda; Junkerman Karin; Levy Victor M.; McCormick Christine B.; Miller Gloria E.; Stevens Barbara; Truman Diane L. 《Canadian Metallurgical Quarterly》1978,33(7):694
Refuted W. M. Cox and V. Catt's (see record 1978-21651-001) findings on productivity ratings of graduate psychology programs based on publication in American Psychological journals. Records from the University of Wisconsin—Madison (UW) for authors whose departmental affiliations were not specified in the various journals were examined. Instead of 8.6%, 40% of the articles associated with UW came from nonpsychology departments. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
423.
An efficient computer program for the analysis of dual-shaped-reflector antennas is described. This is used to predict the crosspolarisation of a typical earth station antenna. Employing a feed with intrinsic crosspolarisation, it is shown that the crosspolar performance of the antenna may be reflector depolarisation limited. The effect of subreflector beam steering on the crosspolar response is also discussed. 相似文献
424.
An asymptotic formula for mode coupling in a finite planar array of circular apertures, which was derived previously, is compared with the exact solution for the case of TE11 mode coupling in two circular waveguides. It is shown that for dominant mode operation of a circular waveguide the asymptotic formula is accurate enough for most practical purposes, even for aperture spacings of the order of a wavelength. 相似文献
425.
The effects of fractions isolated from thermally oxidized corn oil or olive oil on the metabolic activity of heart endothelial
and muscle cells were studied. Rat heart cells in culture, exposed to thermally oxidized fat components, took up more exogenous
1-14C-palmitic acid and incorporated more of it into the cell triacylglycerol fraction than when the cells were treated with fresh
fats. Particularly with the heated corn oil compared to fresh corn oil, much less of the radioactivity from the labeled palmitic
acid was deposited in the phospholipid fraction. Also, with heated corn oil when the incubation period was extended beyond
12 hr, there was a decline in the radioactivity retained in the triacylglycerol fraction of the heart muscle cells. When the
fresh fats were compared for14C-radioactivity incorporation into the heart cells, the olive oil gave much higher values, indicating a distinct difference
in response to the proportion of fatty acids supplied.
Presented in part at the AOCS Meeting, Chicago, September 1976. 相似文献
426.
Neurosyphilis and penicillin levels in cerebrospinal fluid 总被引:3,自引:0,他引:3
JA Mohr W Griffiths R Jackson H Saadah P Bird J Riddle 《Canadian Metallurgical Quarterly》1976,236(19):2208-2209
Because neurosyphilis may progress despite therapy with the recommended penicillin regimens, 15 subjects with positive tests for syphilis in the serum and cerebrospinal fluid (CSF) were studied. All of these patients had CSF pleocytosis. Two received penicillin G (5 and 10 million units per day intravenously, respectively) and 13 received benzathine penicillin G, 3.6 million units per week intramuscularly; treatment lasted four weeks. During intravenous and after intramuscular penicillin therapy, a spinal tap was performed on all subjects; later, assays were done. Of two patients who received intravenous penicillin G, one had 0.3 mug/ml and the other had 2.4 mug/ml penicillin in the CSF. Twelve of 13 patients who received benzathine penicillin G had no detectable penicillin in the CSF; one patient had 0.1 mug/ml penicillin in the CSF. 相似文献
427.
Corn oil and olive oil were thermally oxidized, and the free fatty acids from the fresh fats, and from the distillable non-urea-adductable
(DNUA) fractions of the thermally oxidized fats were prepared. These were added as emulsions to the medium of primary cultures
of heart endothelial and muscle cells from neonatal rats. After exposure for 24 hr, the fatty acid composition of the triacylglycerol
(TC) and phospholipid (PL) fractions of the cells was determined. Reflecting the nature of the fat used, the corn oil treatment
produced relatively higher concentrations of linoleic acid in the TG and PL fractions compared to the olive oil treatment,
in which case the oleic acid level was influenced. Treatment of the cultured cells with components derived from oxidized corn
oil or oxidized olive oil resulted in lower concentrations of linoleic and arachidonic acids in the PL moieties compared to
the fresh fat controls. However, there were marked increases in arachidonic acid in the TG fractions of both the endothelial
and muscle cells. These changes due to the DNUA from thermally oxidized fats indicate a distinct metabolic response to the
derivatives formed during thermal oxidation of the fats. 相似文献
428.
Discusses the impact of the "instant" society of modern America (and the resulting demand in society for instant answers to complex social problems) and the apotheosis of public opinion polls on the courts, judges, and legal institutions of the US during the 1980's. It is argued that institutional attacks on judicial institutions throughout the country reflect a dangerous impatience with the rule of law. It is concluded that Americans must work to construct a safety net for civil liberties and individual freedoms that are threatened by the current emphasis on quick solutions. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
429.
Rubio-Stipec Maritza; Shrout Patrick E.; Bird Hector; Canino Glorisa; Bravo Milagros 《Canadian Metallurgical Quarterly》1989,1(1):30
The Diagnostic Interview Schedule (DIS) was designed for use in large-sample surveys of mental health to produce categorical diagnoses according to criteria such as those found in the third edition of the Diagnostic and Statistical Manual of Mental Disorders, based on structured information about lifetime symptoms provided to nonclinician interviewers. Using symptom data from a probability sample of community residents in Puerto Rico who ranged in age from 18 to 64 (N?=?1,513), we examined five clusters of items (those associated with diagnoses of affective disorders, schizophrenia, phobic disorder, somatization disorder, and alcoholism) and formed quantitative measures of psychopathology from each. We checked the factor structure of these five scales in two probability samples obtained in Los Angeles, one composed of Mexican-Americans (N?=?1,113) and one of Anglo-Americans (N?=?975). Both Los Angeles samples were restricted to persons aged 18 to 64 for these analyses. Evidence of the cross-cultural stability of the DIS Affective Symptoms and Alcoholism scales was obtained. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
430.