全文获取类型
收费全文 | 691篇 |
免费 | 11篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 7篇 |
化学工业 | 120篇 |
金属工艺 | 10篇 |
机械仪表 | 26篇 |
建筑科学 | 61篇 |
能源动力 | 6篇 |
轻工业 | 255篇 |
水利工程 | 3篇 |
石油天然气 | 1篇 |
无线电 | 8篇 |
一般工业技术 | 73篇 |
冶金工业 | 30篇 |
原子能技术 | 1篇 |
自动化技术 | 102篇 |
出版年
2017年 | 5篇 |
2016年 | 5篇 |
2013年 | 146篇 |
2012年 | 8篇 |
2011年 | 10篇 |
2010年 | 3篇 |
2009年 | 6篇 |
2008年 | 12篇 |
2007年 | 11篇 |
2006年 | 6篇 |
2005年 | 7篇 |
2004年 | 7篇 |
2003年 | 10篇 |
2002年 | 9篇 |
2001年 | 4篇 |
2000年 | 8篇 |
1999年 | 7篇 |
1998年 | 26篇 |
1997年 | 22篇 |
1996年 | 16篇 |
1995年 | 12篇 |
1994年 | 13篇 |
1993年 | 10篇 |
1992年 | 10篇 |
1991年 | 10篇 |
1990年 | 19篇 |
1989年 | 13篇 |
1988年 | 27篇 |
1987年 | 16篇 |
1986年 | 8篇 |
1985年 | 20篇 |
1984年 | 11篇 |
1983年 | 18篇 |
1982年 | 7篇 |
1981年 | 11篇 |
1980年 | 7篇 |
1979年 | 10篇 |
1978年 | 14篇 |
1977年 | 14篇 |
1976年 | 11篇 |
1975年 | 8篇 |
1974年 | 10篇 |
1973年 | 4篇 |
1972年 | 5篇 |
1971年 | 6篇 |
1970年 | 4篇 |
1969年 | 6篇 |
1968年 | 20篇 |
1967年 | 16篇 |
1966年 | 6篇 |
排序方式: 共有703条查询结果,搜索用时 11 毫秒
1.
J. T. DICKINSON L. C. JENSEN W. DAVID WILLIAMS 《Journal of the American Ceramic Society》1985,68(5):235-240
We present measurements of the electron, positive ion, and photon emission accompanying the fracture in vacuum of poly-crystalline 95/5 lead zirconate-titanate. The intensities of the charged-particle components of this fractoemission are shown to depend strongly on the direction (relative to the direction of fracture) and magnitude of polarization. The most intense emission is observed when the fracture surfaces are perpendicular to the polarization direction. The emission intensity increases monotonically with polarization. These results are interpreted in terms of a model involving charge separation on the fracture surfaces leading to a microdischarge during fracture. Implications to the interpretation of triboluminesence effects are discussed. 相似文献
2.
Formal Aspects of Computing are dedicated to Professor Rod Burstall, and, as a collection of papers, memoirs and incidental pieces, form a Festschrift
for Rod. The contributions are made by some of the many who know Rod and have been in uenced by him. The research papers included
here represent some of the areas in which Rod has been active, and the editors thank their colleagues for agreeing to contribute
to this Festschrift. 相似文献
3.
PROCESSING AND QUALITY EVALUATION OF WHOLE CANNED 'DWARF' GOLDEN APPLES (SPONDIAS CYTHEREA) 总被引:1,自引:0,他引:1
DAVID RAMSUNDAR EDWARD COMISSIONG NEELA BADRIE GAIL S.H. BACCUS-TAYLOR JOHN SPENCE 《Journal of food quality》2002,25(1):13-25
‘Dwarf’ golden apples (Spondias cytherea) were canned in sucrose syrup of either 30 d?Brix (L) or 40 d?Brix (H). Processing was either by hot filling (HF) of syrup at 92C in filled cans or by steam‐exhausting (SE) of the filled cans at 85C for 12–14 min, followed by processing at 100C for 20 min (W20) or 30 min (W30). Sensory evaluation of commercial sterile products, SE‐LW30 and SE‐LW30 indicated there were no differences (P < 0.05) in appearance, color, taste, aroma and texture. Overall scores indicated that fruits in syrup were liked definitely to like slightly. Panelists indicated that they might or definitely will purchase the products. Fruits in 40 d?Brix syrup were firmer than in 30 d?Brix syrup. By week 8 of storage at 28–30C, pH was stable between 3.6–3.7, and ‘cut‐out’d?Brix of syrup for LW30 and HW30 products was 24.0 – 24.5 and 28.5, respectively. 相似文献
4.
Use of a 5-caffeoylquinic Acid/Caffeine Ratio to Monitor the Coffee Roasting Process 总被引:1,自引:0,他引:1
The extent of alteration in the chemical composition of coffee beans roasted to develop the flavor and aroma associated with coffee beverage was reliably monitored by observing the decomposition of naturally occurring 5-caffeoylquinic acid (5-CQA) and ratioing this concentration to that of the relatively heat stable caffeine. An HPLC method was developed by which simultaneous quantification of 5-CQA and caffeine could be used to monitor degree of roast. 相似文献
5.
Markets and Hierarchies and (Mathematical) Economic Theory 总被引:4,自引:0,他引:4
Over the past decade transaction-cost economics has been partiallytranslated in the more mathematical language of game theory,and understanding of the costs of transactions has been deepened,refined and extended. But the translation is incomplete: a greatdeal of human behaviour is missed, and doing game theory withmore life-like models of individuals will bring theory closerto phenomena. Transaction-cost economics, particulary the economicsof relational contracts, provides a major arena for these developments,since the important issues of bounded rationality and individualbehavior are central to the topic. 相似文献
6.
DAVID SEPÜLVEDA GUADALUPE OLIVAS JOSE-JUAN RODRIGUEZ HEIDI WARNER STEPHANIE CLARK GUSTAVO BARBOSA-CÁNOVAS 《Journal of Food Processing and Preservation》2003,27(3):227-242
Changes in specific physico-chemical and sensory attributes as well as acceptability of beefsteak and beef stew Meal-Ready-to-Eat (MRE) components packed under different headspace levels (10, 20, 30 and 40 cm3 ) and stored at selected temperatures of 4, 27 and 38C (40, 80 and 100F) were evaluated over a six month period. No significant changes in microbial counts, pH, residual oxygen, color, hardness and oxidation occurred in retort-packed beefsteak or beef stew. Unlike beefsteak, beef stew received acceptable scores by consumers during all six months of analysis. Consumers' lack of familiarity with beefsteak may have negatively influenced product acceptability. Beefsteak and beef stew acceptability and specific attributes, particularly moistness and firmness, were detrimentally affected by high storage temperatures. Headspace may be increased to 40 cm3 without significant detrimental effects on product quality and acceptability of beefsteak or beef stew. 相似文献
7.
DAVID RACUSEN 《Journal of Food Biochemistry》1985,9(4):361-367
Patatin, the major glycoprotein of potato tubers, had very similar chemical and physical properties whether isolated from cultivar Desiree or from Kennebec. The patatin of each cultivar exhibited copurification with p-nitrophenyl laurate esterase. However, the esterases from the two sources differed in substrate preference ranging from near equality toward α-naphthyl laurate to a hundredfold difference toward p-nitrophenyl laurate. 相似文献
8.
Defatted field pennycress (Thlaspi arvense L.) seedmeal was found to completely inhibit seedling germination/emergence when added to a sandy loam soil containing wheat (Triticum aestivum L.) and arugula [Eruca vesicaria (L.) Cav. subsp. sativa (Mill.) Thell.] seeds at levels of 1.0% w/w or higher. Covering the pots with Petri dishes containing the soil-seedmeal mixture decreased germination of both species at the lowest application rate (0.5% w/w), suggesting that the some of the phytotoxins were volatile. CH2Cl2, MeOH, and water extracts of the wetted seedmeal were bioassayed against wheat and sicklepod (Senna obtusifolia (L.) H. S. Irwin & Barneby) radicle elongation. Only the CH2Cl2 extract was strongly inhibitory to both species. Fractionation of the CH2Cl2 extract yielded two major phytotoxins, identified by gas chromatography–mass spectrometry and NMR as 2-propen-1-yl (allyl) isothiocyanate (AITC) and allyl thiocyanate (ATC), which constituted 80.9 and 18.8%, respectively, of the active fraction. When seeds of wheat, arugula and sicklepod were exposed to volatilized AITC and ATC, germination of all three species was completely inhibited by both compounds at concentrations of 5 ppm or less. In field studies, where seedmeal was applied at 0.50, 1.25, and 2.50 kg/m2 and tarped with black plastic mulch, all of the treatments significantly reduced dry weight of bioassay plants compared to the tarped control, with the highest seedmeal rate decreasing dry matter to less than 10% of the control 30 d after seedmeal application. Field pennycress seedmeal appears to offer excellent potential as a biofumigant for high-value horticultural crops for both conventional and organic growers.Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by USDA implies no approval of the product to the exclusion of others that may also be suitable. 相似文献
9.
10.
Studies conducted during the sixties and the seventies on food crops in Uganda showed that the populace was exposed to consumption of aflatoxin-contaminated foods. These studies also linked the highest incidence of liver cancer in the world to the presence of high levels of aflatoxins in the food and beverages. After a lapse of a decade, it was of interest to investigate the occurrence of aflatoxins and aflatoxigenic fungi in staple Ugandan food crops and poultry feeds derived from these foodstuffs. A simple, rapid and reproducible procedure was used. The procedure consisted of growing or culturing feed grains on a selective medium, Aspergillus flavus/parasiticus agar (AFPA) followed by screening for aflatoxin producing fungi on a coconut agar medium (CAM) under UV light with a subsequent confirmatory screening method for aflatoxin production by the fungi in pure culture. Fifty-four samples consisting of corn and peanuts, soybean and poultry feed were analyzed for content of aflatoxigenic. A. flavus/parasiticus and 25 of the samples were also screened for aflatoxins B1 and G1, zearalenone, sterigmatocystin, ochratoxin A, citrinin, vomitoxin, and diacetoxyscirpenol (DAS). Aflatoxigenic A. flavus/parasiticus was detected from the majority of corn (77%), peanuts (36% human food and 83.3% animal feed) and poultry feed (66.6%). but not from soybean samples. Two samples out of 25 contained detectable levels of aJatosin B, (20 ppb). For the jirst time other mycotoxins, zearalenone (3 samples) and vomitoxin (2 samples) were detected in corn from Uganda. 相似文献