全文获取类型
收费全文 | 215篇 |
免费 | 6篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 20篇 |
金属工艺 | 3篇 |
机械仪表 | 3篇 |
建筑科学 | 5篇 |
矿业工程 | 1篇 |
轻工业 | 56篇 |
水利工程 | 1篇 |
无线电 | 15篇 |
一般工业技术 | 16篇 |
冶金工业 | 87篇 |
原子能技术 | 1篇 |
自动化技术 | 10篇 |
出版年
2021年 | 3篇 |
2019年 | 3篇 |
2017年 | 6篇 |
2016年 | 2篇 |
2014年 | 3篇 |
2013年 | 7篇 |
2012年 | 4篇 |
2011年 | 7篇 |
2010年 | 4篇 |
2009年 | 10篇 |
2008年 | 6篇 |
2007年 | 8篇 |
2006年 | 7篇 |
2005年 | 7篇 |
2004年 | 5篇 |
2003年 | 6篇 |
2002年 | 4篇 |
2001年 | 4篇 |
2000年 | 4篇 |
1999年 | 6篇 |
1998年 | 24篇 |
1997年 | 16篇 |
1996年 | 5篇 |
1995年 | 2篇 |
1994年 | 5篇 |
1993年 | 7篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 5篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1980年 | 2篇 |
1977年 | 1篇 |
1976年 | 5篇 |
1974年 | 3篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 2篇 |
1968年 | 1篇 |
1966年 | 1篇 |
1961年 | 2篇 |
1924年 | 1篇 |
1922年 | 1篇 |
1921年 | 1篇 |
排序方式: 共有221条查询结果,搜索用时 7 毫秒
1.
2.
3.
J Golomb MJ de Leon A Kluger AE George C Tarshish SH Ferris 《Canadian Metallurgical Quarterly》1993,50(9):967-973
OBJECTIVE: To estimate the prevalence of radiographically detectable hippocampal atrophy (HA) in a normal aging sample and to test whether such atrophy is associated with memory dysfunction. DESIGN: One hundred fifty-four medically healthy and cognitively normal elderly persons (aged 55 to 88 years) received magnetic resonance imaging and/or computed tomographic scans designed to identify HA. One hundred forty-five of these subjects also underwent psychometric tests of memory function. Multivariate analyses of variance were used to evaluate differences in memory performance between subjects with and without HA. SETTING: This study was conducted at a research clinic for the investigation of age-associated neuropsychological and neuroradiologic changes. PARTICIPANTS: Based on the following criteria, 154 subjects were consecutively selected from a larger group of elderly research volunteers participating in a study of normal aging: age of 55 years or greater; Global Deterioration Scale score of 2 or less; and Mini-Mental State examination score of 28 or greater. Subjects with evidence for significant medical, psychiatric, or neurologic disease were excluded. MAIN OUTCOME MEASURES: Outcome measurements included individual psychometric test scores and computed tomographic-magnetic resonance imaging hippocampal atrophy ratings. RESULTS: Nearly 33% of the subjects had radiographic evidence for HA. The prevalence of HA increased significantly with age and was more common in male than female subjects. After controlling for age, level of education, and vocabulary, subjects with HA were found to perform more poorly on tests of recent (secondary) verbal memory when compared with subjects without HA (P < .01). No significant differences were found for tests of immediate (primary) memory. CONCLUSION: We conclude that HA is a common accompaniment of normal aging and is associated with mild memory impairment. Additional research is needed to determine whether HA constitutes a significant risk for future dementia. 相似文献
4.
Local‐scale Benefits of River Connectivity Restoration Planning Beyond Jurisdictional Boundaries 下载免费PDF全文
A. W. Milt P. J. Doran M. C. Ferris A. T. Moody T. M. Neeson P. B. McIntyre 《河流研究与利用》2017,33(5):788-795
Conservation planning aims to optimize outcomes for select species or ecosystems by directing resources toward high‐return sites. The possibility that local benefits might be increased by directing resources beyond the focal area is rarely considered. We present a case study of restoring river connectivity for migratory fish of the Great Lakes Basin by removing dams and road crossings within municipal jurisdictions versus their broader watersheds. We found that greater river connectivity could often be achieved by considering both intra‐jurisdictional and extra‐jurisdictional barriers. Focusing on jurisdictional barriers alone generally forfeited <20% (median = 0%) of habitat gains for those who value solely habitat gains within the jurisdiction, but >75% (median = 100%) for planners who value larger‐scale habitat gains. Similarly, cost savings tended to be between ?50% and +50%, but in some cases were very negative. Our study underscores the local‐scale benefits of broadening restoration investments, especially for decision makers of the Great Lakes Basin and contributes to a discussion of appropriate and efficient scales of conservation planning. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
5.
Robin A. Henderson Robert G. Jensen Carol J. Lammi-Keefe Ann M. Ferris Kenneth R. Dardick 《Lipids》1992,27(11):863-869
To examine the effect of fish oil supplementation on the fatty acid (FA) composition of human milk and maternal and infant
erythrocytes, five lactating women were supplemented with 6 g of fish oil daily for 21d. Usual maternal diets contained 1,147
mg of total n−3 FA, with 120 mg from very long-chain (>C18) n−3 FA. Supplementation increased dietary levels to 3,092 mg of total n−3 FA and 2,006 mg of very long-chain n−3 FA. Milk
samples were collected daily, prior to fish oil ingestion, and at 4-h intervals on days 1, 7, 14 and 21. Milk n−3 FA content
increased within 8 h and reached steady state levels within one week. The n−6 fatty acid content decreased. Erythrocyte eicosapentaenoic
acid content increased from 0.24% to 1.4% (P<0.01) in mothers and from 0.11% to 0.70% (P<0.05) in infants. Docosapentaenoic acid increased from 1.4% to 2.2% (P<0.05) in mothers and from 0.30% to 0.78% (P<0.01) in infants. There was no significant change in docosahexaenoic acid or n−6 fatty acid content. Maternal platelet aggregation
responses were variable. No differences in milk or plasma tocopherol levels were noted.
Based on a paper presented at the Symposium on Milk Lipids held at the AOCS Annual Meeting, Baltimore, MD, April 1990. 相似文献
6.
Michael C. Ferris 《Optimization methods & software》2016,31(5):1064-1088
We propose a bi-level optimization model for demand response in organized wholesale energy markets. In this model, the lower level performs the economic dispatch of energy and generates the price and the upper level minimizes the total amount of demand response subject to a net benefit requirement. In an economic sense, demand response is a trade of ‘consuming rights’ instead of a sale of energy. Therefore it must be traded separately from the energy market. Although a bi-level optimization model is very hard to solve in general, we demonstrate that realistic power networks have characteristics that can be exploited to reduce the effective size of the problem instance. In particular, we transform the nonconvex net benefit test constraint to an equivalent linear form, and reformulate the nonconvex complementarity conditions of doubly bounded variables using SOS2 constraints. For realistic instances of the MPEC, we employ a three-phase approach that exploits the fast local solution from a nonlinear programming solver as well as LP-based bound strengthening within a mixed integer/SOS2 formulation. The model is tested against various data cases and settings, and generates useful insight for demand response dispatch operations in practice. 相似文献
7.
8.
Ferris Patricia A.; Sinclair Christina; Kline Theresa J. 《Canadian Metallurgical Quarterly》2005,10(3):225
In a cross-sectional sample of 428 employees, the job demand-control-support and effort-reward imbalance job stress models were amalgamated and expanded to include modifiable risk factors and noncontrollable genetic factors related to cardiovascular disease (CVD) risk. With structural equation modeling, the constructs of lack of job resilience, lack of personal resilience, and job demand were used to examine how employer and employee factors related to psychosomatic strain and risk indicators of CVD. Negative perception of job demand predicted perception of lack of job resilience but not lack of personal resilience. Lack of job and personal resilience predicted strain. Women reported greater strain than men. CVD risk was predicted by strain, age, sex, and family history. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
10.