全文获取类型
收费全文 | 1705篇 |
免费 | 102篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 22篇 |
综合类 | 2篇 |
化学工业 | 386篇 |
金属工艺 | 31篇 |
机械仪表 | 56篇 |
建筑科学 | 74篇 |
矿业工程 | 5篇 |
能源动力 | 107篇 |
轻工业 | 171篇 |
水利工程 | 17篇 |
石油天然气 | 8篇 |
无线电 | 175篇 |
一般工业技术 | 305篇 |
冶金工业 | 104篇 |
原子能技术 | 19篇 |
自动化技术 | 332篇 |
出版年
2024年 | 5篇 |
2023年 | 18篇 |
2022年 | 36篇 |
2021年 | 49篇 |
2020年 | 42篇 |
2019年 | 54篇 |
2018年 | 74篇 |
2017年 | 46篇 |
2016年 | 81篇 |
2015年 | 47篇 |
2014年 | 77篇 |
2013年 | 149篇 |
2012年 | 99篇 |
2011年 | 128篇 |
2010年 | 83篇 |
2009年 | 153篇 |
2008年 | 94篇 |
2007年 | 87篇 |
2006年 | 77篇 |
2005年 | 40篇 |
2004年 | 39篇 |
2003年 | 27篇 |
2002年 | 32篇 |
2001年 | 23篇 |
2000年 | 18篇 |
1999年 | 15篇 |
1998年 | 22篇 |
1997年 | 13篇 |
1996年 | 13篇 |
1995年 | 19篇 |
1994年 | 8篇 |
1993年 | 11篇 |
1991年 | 9篇 |
1990年 | 10篇 |
1989年 | 5篇 |
1988年 | 6篇 |
1987年 | 7篇 |
1986年 | 8篇 |
1985年 | 8篇 |
1984年 | 8篇 |
1983年 | 13篇 |
1982年 | 9篇 |
1981年 | 8篇 |
1979年 | 7篇 |
1978年 | 4篇 |
1977年 | 6篇 |
1976年 | 4篇 |
1975年 | 5篇 |
1974年 | 3篇 |
1973年 | 5篇 |
排序方式: 共有1814条查询结果,搜索用时 0 毫秒
61.
Multimedia Tools and Applications - Single image super resolution (SR) based on sparse representation is a promising technique where the SR problem is solved by searching for the most robust... 相似文献
62.
63.
Nielsen Guillaume Coudert Lucie Janin Amelie Blais Jean Francois Mercier Guy 《Mine Water and the Environment》2019,38(1):104-118
Mine Water and the Environment - Acid mine drainage (AMD) is a major environmental challenge for the mining industry in northern climates. Laboratory-scale experiments were conducted to test... 相似文献
64.
Temperature fluctuations during storage and transportation are the most important factors affecting quality and shelf life of food products. Phase change materials (PCM) with their isothermal characteristics are used to control temperature in various thermal operations. In this study, octanoic acid as PCM candidate was used in a packaging material design for thermal control of a food product. The PCM candidate was microencapsulated in different shell materials in our laboratory. Among the synthesized microcapsules, microencapsulated PCM (mPCM) (ΔHm = 42.9 J/g) with styrene polymer as the shell material was selected based on its properties of being cost effective and compatibility with human health. Thermal buffering effect of PCM in bulk and microencapsulated forms was tested in a packaging design with special PCM pockets. Results showed that packages with mPCM and bulk PCM provided 8.8 and 6 hours of thermal buffering effect for 160 g of chocolate compared with the package without PCM (reference package). 相似文献
65.
66.
Devlieghere F Francois K Vereecken KM Geeraerd AH Van Impe JF Debevere J 《Journal of food protection》2004,67(9):1977-1990
In contrast with most chemical hazardous compounds, the concentration of food pathogens changes during processing, storage, and meal preparation, making it difficult to estimate the number of microorganisms or the concentration of their toxins at the moment of ingestion by the consumer. These changes are attributed to microbial proliferation, survival, and/or inactivation and must be considered when exposure to a microbial hazard is assessed. The number of microorganisms can also change as a result of physical removal, mixing of food ingredients, partitioning of a food product, or cross-contamination (M. J. Nauta. 2002. Int. J. Food Microbiol. 73:297-304). Predictive microbiology, i.e., relating these microbial evolutionary patterns to environmental conditions, can therefore be considered a useful tool for microbial risk assessment, especially in the exposure assessment step. During the early development of the field (late 1980s and early 1990s), almost all research was focused on the modeling of microbial growth over time and the influence of temperature on this growth. Later, modeling of the influence of other intrinsic and extrinsic parameters garnered attention. Recently, more attention has been given to modeling of the effects of chemicals on microbial inactivation and survival. This article is an overview of different applied strategies for modeling the effect of chemical compounds on microbial populations. Various approaches for modeling chemical growth inhibition, the growth-no growth interface, and microbial inactivation by chemicals are reviewed. 相似文献
67.
Levels and distribution of polybrominated diphenyl ethers in water, surface sediments, and bivalves from the San Francisco Estuary 总被引:5,自引:0,他引:5
Polybrominated diphenyl ethers (PBDEs) were found in water, surface sediments, and bivalve samples that were collected from the San Francisco Estuary in 2002. sigmaPBDE concentrations in water samples ranged from 3 to 513 pg/ L, with the highest concentrations found in the Lower South Bay (range 103-513 pg/L) region, which receives approximately 26% of the Estuary's wastewater treatment plant effluents. The sigmaPBDEs in sediments ranged from below detection limits to 212 ng/g dry wt, with the highest concentration found at a South Bay station (212 ng/g dry wt), which was up to 3 orders of magnitude higher than other stations. The sigmaPBDE concentrations ranged from 9 to 64 ng/g dry wt in oysters (Crassostrea gigas), from 13 to 47 ng/g dry wt in mussels (Mytilus californianus), and from 85 to 106 ng/g dry wt in clams (Corbicula fluminea). Only three PBDE congeners were detected in bivalves, BDE-47, BDE-99, and BOE-100; these are the most bioaccumulative congeners from the commercial Penta-BDE mixture. 相似文献
68.
David Mantilla Hordur G Kristinsson Murat O Balaban W Steven Otwell Frank A Chapman Sivakumar Raghavan 《Journal of the science of food and agriculture》2008,88(8):1394-1399
BACKGROUND: Color of muscle foods plays a major role in consumer perception of meat quality. Carbon monoxide (CO) has been successfully used for improving color of packaged meat and fish products. In this study, we wanted to investigate pre‐mortem treatment of live tilapia using 100% CO for its ability to improve the color of frozen whole tilapia. We compared untreated and CO‐treated whole, gutted tilapia, frozen for 2 and 4 months at ? 20 °C. Frozen tilapia samples were thawed overnight at 4 °C, filleted and analyzed for their color, heme peak wavelength and CO concentration. RESULTS: Euthanasia using CO significantly increased redness (a* value) and lightness (L* value) of tilapia white and red muscle. Frozen storage significantly (P < 0.05) decreased redness of both CO‐treated and untreated tilapia. However, even after 4 months of frozen storage, a*‐value of CO‐treated tilapia was similar to fresh untreated tilapia fillets. Heme peak wavelengths of CO‐euthanized tilapia were higher than in untreated tilapia and there was no significant (P > 0.05) decrease in heme peak wavelengths of CO‐treated tilapia white and red muscle during frozen storage. The CO content of frozen euthanized tilapia fillets was significantly (P > 0.05) higher than in untreated fillets. In general, red muscle tissue of euthanized tilapia had a higher concentration of CO than white muscle. CONCLUSION: Color stability of tilapia fillets was significantly improved by pre‐mortem CO treatment. The color of CO‐treated fillets was retained during frozen storage compared to untreated fillets. Hence, pre‐mortem CO treatment could be used as a new method for improving color of tilapia. Copyright © 2008 Society of Chemical Industry 相似文献
69.
Ergin Murat Altuner Hami Alpas Yasar Kemal Erdem Faruk Bozoglu 《European Food Research and Technology》2006,222(3-4):392-396
Interest in high hydrostatic pressure (HHP) applications on milk and dairy products has recently increased as HHP offers a
new technology for food preservation to the food industry. Although HHP-induced microbial destruction, rennet or acid coagulation
of milk and increase in cheese yield has been reported, the actual effect of HHP application on milk constituents still remains
to be unexplained. Therefore, we have analyzed the effect of HHP on physicochemical and biochemical properties such as turbidity,
pH and especially protein micelle surface hydrophobicity of milk proteins. To serve for this purpose, milk samples with different
fat contents were pressurized from 110 to 440 MPa at 25 °C for 10 and 20 min. Turbidity decreased with pressure increase and
there was a slight change in pH. In order to measure the extent of exposure of hydrophobic groups of proteins to HHP, the
method described by Bonomi et al. [1], based on use of a fluorescent probe, was utilized. In the light of the results obtained, it can be concluded that HHP has
an effect on non-covalent interactions and especially hydrophobic bonds in milk. As the pressure is increased from 110 to
440 MPa, the micelles possibly decompose into sub-micelles and the embedded hydrophobic areas inside these micelles re-position
in such a way that they can readily interfere with the fluorescent marker, ANS. These results may lead to practical applications
of HHP treatment in the dairy industry to produce microbiologically safe, minimally processed products with high nutritional
and sensory quality and novel texture. 相似文献
70.
Murat Durandurdu 《Journal of the American Ceramic Society》2016,99(5):1594-1600
The high‐pressure behavior of amorphous aluminum nitride is investigated for the first time by means of ab initio molecular dynamics simulations. It is found to undergo two successive first‐order phase transformations with the application of pressure. The first one is a polyamorphic phase transition in which the low‐density amorphous phase transforms into a high‐density amorphous phase having an average coordination number of about 4.6. The high‐density amorphous structure transforms back to a low‐coordinated amorphous network upon pressure release but its density is higher than that of the original low‐density amorphous phase. The second phase change is the crystallization of the high‐density amorphous state into a rocksalt structure. A careful analysis suggests that the hexagonal‐like nanoclusters presented in amorphous aluminum nitride prevent the formation of a very dense amorphous phase (about sixfold coordinated) during the first phase transition and they act as a nucleation center for the crystallization process. 相似文献