全文获取类型
收费全文 | 367篇 |
免费 | 0篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 47篇 |
金属工艺 | 3篇 |
机械仪表 | 3篇 |
建筑科学 | 9篇 |
矿业工程 | 1篇 |
能源动力 | 3篇 |
轻工业 | 85篇 |
水利工程 | 4篇 |
石油天然气 | 3篇 |
无线电 | 17篇 |
一般工业技术 | 45篇 |
冶金工业 | 117篇 |
原子能技术 | 1篇 |
自动化技术 | 27篇 |
出版年
2023年 | 3篇 |
2022年 | 3篇 |
2021年 | 4篇 |
2020年 | 2篇 |
2018年 | 2篇 |
2016年 | 5篇 |
2015年 | 4篇 |
2014年 | 6篇 |
2013年 | 11篇 |
2012年 | 9篇 |
2011年 | 11篇 |
2010年 | 16篇 |
2009年 | 5篇 |
2008年 | 9篇 |
2007年 | 9篇 |
2006年 | 14篇 |
2005年 | 16篇 |
2004年 | 9篇 |
2003年 | 10篇 |
2002年 | 9篇 |
2001年 | 5篇 |
2000年 | 10篇 |
1999年 | 9篇 |
1998年 | 32篇 |
1997年 | 20篇 |
1996年 | 16篇 |
1995年 | 15篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1991年 | 7篇 |
1990年 | 7篇 |
1989年 | 11篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 8篇 |
1985年 | 10篇 |
1984年 | 6篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1971年 | 3篇 |
1958年 | 1篇 |
1957年 | 1篇 |
1939年 | 1篇 |
1934年 | 1篇 |
1927年 | 1篇 |
排序方式: 共有367条查询结果,搜索用时 31 毫秒
11.
Native potato, waxy corn, corn, wheat, filed pea and lentil starches were autoclaved at 15 psi, 121°C for 1min. Scanning electron micrographs of the native and autoclaved starches showed no changes in granular surfaces and shapes. In all starches, the X-ray intensities at most of the d-spacings between 3-18 Å increased upon autoclaving, being more pronounced in potato. The X-ray patterns of cereals and legumes remained unchanged, while that of tuber (potato) became more cereal-like. Differential scanning calorimetry of the starch samples revealed that autoclaving increased the gelatinization transition temperatures of wheat but decreased that of potato; the changes observed in waxy corn, corn, field pea and lentil starches were very small. The gelatinization enthalpy of all native starches decreased upon autoclaving while the percentage decrease was highly marked in potato. Image analysis of the native and autoclaved starches revealed changes in the granule size distribution patterns. Also, the population mean area of all native starch granules considerably increased upon autoclaving. Acetyl binding capacity, measured at 5% and 10% acetic anhydride addition levels, was higher in autoclaved than in native starches. Furthermore, autoclaving had no influence on starch cationization, studied at 3% and 6% reagent addition levels. The results indicated that the changes in starch molecular organization caused by autoclaving enhanced its reactivity towards acetylation but not cationization. 相似文献
12.
Chemical factors involved in ruminal fiber digestion 总被引:11,自引:0,他引:11
W H Hoover 《Journal of dairy science》1986,69(10):2755-2766
In the United States, cattle are commonly fed diets containing cereal grains. The presence of starch and sugars reduces fiber digestion, which may in turn depress intake. In this paper, chemical constraints that may be responsible for the decrease in fiber digestion are explored. A major factor appears to be rumen pH. Moderate depression in pH, to approximately 6.0, results in a small decrease in fiber digestion, but numbers of fibrolytic organisms are usually not affected. Further decreases to 5.5 or 5.0 result in depressed growth rates and decreased fibrolytic microbes, and fiber digestion may be completely inhibited. Proliferation of organisms on readily fermentable carbohydrates may increase the need for total nitrogen as both ammonia and amino acids. The value of amino acids to cellulolytic organisms appears to be primarily as sources of isobutyric, isovaleric, and 2-methylbutyric acids. This reinforces the need to establish dietary requirements for nonprotein nitrogen, degradable protein, and isoacids. Other factors affecting fiber digestion, such as inhibition of cellulytic enzymes and plant concentrations of lignins and phenyl propanoids, are also discussed. 相似文献
13.
Locating blood vessels in retinal images by piecewise threshold probing of a matched filter response 总被引:10,自引:0,他引:10
We describe an automated method to locate and outline blood vessels in images of the ocular fundus. Such a tool should prove useful to eye care specialists for purposes of patient screening, treatment evaluation, and clinical study. Our method differs from previously known methods in that it uses local and global vessel features cooperatively to segment the vessel network. We evaluate our method using hand-labeled ground truth segmentations of 20 images. A plot of the operating characteristic shows that our method reduces false positives by as much as 15 times over basic thresholding of a matched filter response (MFR), at up to a 75% true positive rate. For a baseline, we also compared the ground truth against a second hand-labeling, yielding a 90% true positive and a 4% false positive detection rate, on average. These numbers suggest there is still room for a 15% true positive rate improvement, with the same false positive rate, over our method. We are making all our images and hand labelings publicly available for interested researchers to use in evaluating related methods. 相似文献
14.
Dallas G. Hoover Ph.D. Prasad S. Dhurjati Robert J. Leipold Dallas G. Hoover Ph.D. Dietrich Knorr Robert J. Fisher 《Food Biotechnology》2013,27(2):283-299
Modern Food Microbiology, Third Edition. J.M. Jay. Van Nostrand Reinhold, 115 Fifth Ave., New York, NY 10003. 642 pp. 1986. $29.95 (US). Title: Fermentation and Biochemical Engineering Handbook; Principles, Process Design, and Equipment Author(s): Henry C. Vogel (Editor) Publisher: Noyes Publications, Park Ridge, NJ. 1986 Principles of Fermentation Technology P.F. Stanbury and A. Whitaker Pergamon Press Inc., Elm3ford, NY, USA 225 pp., 1984, $19.25 (soft cover), $48.00 (hard cover) Biotechnology in Agricultural Chemistry H.M. Le Baron, R.O. Mumma, R.C. Honeycutt and J.H. Duesing (eds) ACS Symposium Series 33t, American Chemical Society, Washington, DC 367 pp., 1987, $64.95 (US) Supercritical Fluids ‐ Chemical and Engineering Principles and Applications T.G. Squires and M.E. Paulaitis (Editors) ACS Symposium Series #329, 294pp., $59.95 (US & Canada), $71.95 (Export) Title: Biogeneration of aromas. Authors: Parliment, T. H. and R. Croteau (Editors) Publishers: ACS Symposium Series, Washington, DC, 1986 Title: Ecology and Metabolism of Plant Lipids Author(s): Glenn Fuller and W. David Nes (Editors) Publisher: American Chemical Society. Symposium Series, Washington DC, 1986 Title: Chemistry and Function of Pectins Author(s): Fishman, M.L. and Jen, J.J. Publisher: ACS Symposium Series, Washington, DC 1986 “Plant Proteins: Applications, Biological Effects and Chemistry”; R.L. Ory (ed), ACS Symposium Series, American Chemical Society 1155 Sixteenth Street NW, Washington, DC 20036, USA 285 PP, 1986, $59.95 (U.S. and Canada) 相似文献
15.
Amanda N. Elkins Eric R. Muth Adam W. Hoover Alexander D. Walker Thomas L. Carpenter Fred S. Switzer 《Applied ergonomics》2009,40(6):997-1003
Physiological compliance (PC) refers to the correlation between physiological measures of team members over time. The goals of this study were to examine ways of measuring PC in heart rate variability (HRV) data and the relationship between PC and team performance. Teams were tasked with entering both real and simulated rooms and “shooting” individuals with a weapon and identifying individuals without a weapon. The linear correlation and directional agreement PC methods were shown to be the most sensitive to differences in performance, with greater PC being associated with better performance. The correlation method when applied to a measure of respiratory sinus arrhythmia (RSA) revealed a significant difference between high and low performers (t[8] = −2.31, p = 0.03) and the directional agreement applied to inter-beat-intervals and RSA revealed trend-level differences (t[4.62] = −1.86, p = 0.06 and t[8] = −1.68, p = 0.07). These results suggest that PC may have merit for predicting team performance. 相似文献
16.
J. Hoover S. A. Meguid 《International Journal of Mechanics and Materials in Design》2011,7(2):111-121
The suspended-load backpack is found to improve the energy efficiency of walking with a load in some scenarios. The objective
of this study is to (i) analyze the dynamic load of the suspended-load backpack over a range of walking speeds and pack masses,
and (ii) determine the optimal design parameters for the suspended-load backpack to minimize the effect of dynamic load on
the efficiency of walking. A simple spring, damper and mass system is used to model the performance of the suspended-load
backpack as well as the typical hiking pack. The oscillating load and phase angle are calculated over a range of loading and
spring stiffness values to determine the system resonance and optimal spring stiffness design range for the suspended-load
backpack. Our results reveal that the stiffness for the suspended-load backpack should be designed below one half of the resonance
stiffness to minimize dynamic loads at a given walking speed. The location and magnitude of the maximum phase angle is also
calculated. A performance comparison between the suspended-load backpack and a typical hiking pack demonstrates the beneficial
range for the suspended-load backpack. The suspended-load backpack is found to provide significant reductions in the peak
backpack load, compared with a typical hiking pack, while carrying large loads at fast walking speeds. The suspended-load
backpack performs poorly for low pack loads due to in-phase oscillations between the pack and the walking person. 相似文献
17.
Guy Hoover 《电子设计技术》2010,17(6)
引言
设计一种能够提供不打任何性能折扣的ADC驱动拓扑结构是颇具挑战性,特别是在围绕一款诸如1Msps LTC(R)2393-16等超低噪声SAR ADC进行设计的时候. 相似文献
18.
Two patients with sinus tracts from retained T-fasteners following PEG tube placement are reported. Both patients had the PEG tubes subsequently removed and presented with purulent discharge and granulations near well-healed gastrostomy sites. The management of this complication and a possible method of prevention are discussed. 相似文献
19.
20.