全文获取类型
收费全文 | 598篇 |
免费 | 32篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 105篇 |
金属工艺 | 17篇 |
机械仪表 | 15篇 |
建筑科学 | 57篇 |
矿业工程 | 2篇 |
能源动力 | 15篇 |
轻工业 | 76篇 |
水利工程 | 3篇 |
石油天然气 | 3篇 |
无线电 | 55篇 |
一般工业技术 | 89篇 |
冶金工业 | 60篇 |
原子能技术 | 4篇 |
自动化技术 | 129篇 |
出版年
2023年 | 2篇 |
2022年 | 1篇 |
2021年 | 9篇 |
2020年 | 12篇 |
2019年 | 10篇 |
2018年 | 20篇 |
2017年 | 14篇 |
2016年 | 16篇 |
2015年 | 17篇 |
2014年 | 20篇 |
2013年 | 53篇 |
2012年 | 41篇 |
2011年 | 50篇 |
2010年 | 46篇 |
2009年 | 34篇 |
2008年 | 32篇 |
2007年 | 39篇 |
2006年 | 29篇 |
2005年 | 24篇 |
2004年 | 25篇 |
2003年 | 20篇 |
2002年 | 16篇 |
2001年 | 12篇 |
2000年 | 8篇 |
1999年 | 8篇 |
1998年 | 9篇 |
1997年 | 8篇 |
1996年 | 6篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1993年 | 7篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1989年 | 5篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1985年 | 5篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1974年 | 3篇 |
1968年 | 3篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有633条查询结果,搜索用时 15 毫秒
1.
2.
Clean Technologies and Environmental Policy - Energy efficiency in manufacturing is important for overall sustainability of society. This paper combines three observations to improve an overlooked... 相似文献
3.
4.
Han Bit Lee Young Won Kim Sang Hoon Kim Suk Hee Park Joon‐Phil Choi Clodualdo Aranas Jr. 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(33)
A modular solder system with hierarchical morphology and micro/nanofeatures in which solder nanoparticles are distributed on the surface of template micropowders is reported. A core–shell structure of subsidiary nanostructures, which improved the intended properties of the modular solder is also presented. In addition, polymer additives can be used not only as an adhesive (like epoxy resin) but also to impart other functions. By combining all of these, it is determined that the modular solder system is able to increase reflowability on a heat‐sensitive plastic substrate, oxidation resistance, and electrical conductivity. In this respect, the system could be readily modified by changing the structure and composition of each constituent and adopting backward compatibility with which the knowledge and information attained from a previously designed solder can offer feedback toward further improving the properties of a newly designed one. In practice, In–Sn–Bi nanoparticles engineered on the surface of Sn–Zn micropowders result in pronounced reflowing on a flexible Au‐coated polyethylene terephthalate (PET) substrate even at the low temperature of 110 °C. Depending on their respective concentrations, the incorporation of CuO@CeO2 nanostructures and poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) polymers increases oxidation resistance and electrical conductivity of the modular solder. 相似文献
5.
6.
Phil Symonds David Rees Zornitza Daraktchieva Neil McColl Jane Bradley Ian Hamilton Michael Davies 《Indoor air》2019,29(5):854-864
Exposure to radon gas is the second leading cause of lung cancer worldwide behind smoking. Changing the energy characteristics of a dwelling can influence both its thermal and ventilative properties, which can affect indoor air quality. This study uses radon measurements made in 470 689 UK homes between 1980 and 2015, linked to dwelling information contained within the Home Energy Efficiency Database (HEED). The linked dataset, the largest of its kind, was used to analyze the association of housing and energy performance characteristics with indoor radon concentrations in the UK. The findings show that energy efficiency measures that increase the airtightness of properties are observed to have an adverse association with indoor radon levels. Homes with double glazing installed had radon measurements with a significantly higher geometric mean, 67% (95% CI: 44, 89) greater than those without a recorded fabric retrofit. Those with loft insulation (47%, 95% CI: 26, 69) and wall insulation (32%, 95% CI: 11, 53) were also found to have higher radon readings. Improving the energy performance of the UK's housing stock is vital in meeting carbon emission reduction targets. However, compromising indoor air quality must be avoided through careful assessment and implementation practices. 相似文献
7.
Enhanced efficiency fertilisers: a review of formulation and nutrient release patterns 总被引:4,自引:0,他引:4 下载免费PDF全文
Yakindra Prasad Timilsena Raju Adhikari Phil Casey Tim Muster Harsharn Gill Benu Adhikari 《Journal of the science of food and agriculture》2015,95(6):1131-1142
Fertilisers are one of the most important elements of modern agriculture. The application of fertilisers in agricultural practices has markedly increased the production of food, feed, fuel, fibre and other plant products. However, a significant portion of nutrients applied in the field is not taken up by plants and is lost through leaching, volatilisation, nitrification, or other means. Such a loss increases the cost of fertiliser and severely pollutes the environment. To alleviate these problems, enhanced efficiency fertilisers (EEFs) are produced and used in the form of controlled release fertilisers and nitrification/urease inhibitors. The application of biopolymers for coating in EEFs, tailoring the release pattern of nutrients to closely match the growth requirement of plants and development of realistic models to predict the release pattern of common nutrients have been the foci of fertiliser research. In this context, this paper intends to review relevant aspects of new developments in fertiliser production and use, agronomic, economic and environmental drives for enhanced efficiency fertilisers and their formulation process and the nutrient release behaviour. Application of biopolymers and complex coacervation technique for nutrient encapsulation is also explored as a promising technology to produce EEFs. © 2014 Society of Chemical Industry 相似文献
8.
Chamil Abeykoon Peter J. Martin Adrian L. Kelly Kang Li Elaine C. Brown Phil D. Coates 《Polymer Engineering and Science》2014,54(10):2430-2440
Polymer extrusion is fundamental to the processing of polymeric materials and melt flow temperature homogeneity is a major factor which influences product quality. Undesirable thermal conditions can cause problems such as melt degradation, dimensional instability, weaknesses in mechanical/optical/geometrical properties, and so forth. It has been revealed that melt temperature varies with time and with radial position across the die. However, the majority of polymer processes use only single‐point techniques whose thermal measurements are limited to the single point at which they are fixed. Therefore, it is impossible for such techniques to determine thermal homogeneity across the melt flow. In this work, an extensive investigation was carried out into melt flow thermal behavior of the output of a single extruder with different polymers and screw geometries over a wide range of processing conditions. Melt temperature profiles of the process output were observed using a thermocouple mesh placed in the flow and results confirmed that the melt flow thermal behavior is different at different radial positions. The uniformity of temperature across the melt flow deteriorated considerably with increase in screw rotational speed while it was also shown to be dependent on process settings, screw geometry, and material properties. Moreover, it appears that the effects of the material, machine, and process settings on the quantity and quality of the process output are heavily coupled with each other and this may cause the process to be difficult to predict and variable in nature. POLYM. ENG. SCI., 54:2430–2440, 2014. © 2013 Society of Plastics Engineers 相似文献
9.
Boram Seo Woo Hyung Jeon Chul‐Eui Kim Sanghyuck Kim Sung Hong Kim Phil Ho Lee 《Advanced Synthesis \u0026amp; Catalysis》2016,358(7):1078-1087
Sequential copper‐catalyzed [3+2] cycloaddition, rhodium‐catalyzed O H insertion, intramolecular 1,8‐addition, and rearrangement starting from 1‐alkynes, N‐sulfonyl azides, and tropolones is demonstrated for the synthesis of the 2‐functionalized aminotropones in one pot. These results indicate that sequential functionalization of O H and C(sp2) O bonds smoothly occurs in the C(sp2) O H bonds of tropolone
10.
Davies H Weber P Lindsay P Craw D Pope J 《The Science of the total environment》2011,409(15):2971-2980
The Stockton coal mine lies at 700-1100 m above sea level in a mountainous orographic precipitation zone on the West Coast of the South Island of New Zealand. Rainfall exceeds 6000 mm/year and arrives with frequent flood events that can deliver > 200 mm/day. Streams vary in discharges by up to two orders of magnitude over a time scale of hours. Pyritic waste rock at the mine interacts chemically with even the most intense rainfall, and almost all runoff is acidic to some degree. In the most intense rain event recorded in this study (> 10 mm/hour), dilution of acid mine drainage (AMD) occurred and pH rose from 3 to > 5 over several hours, with stream discharge at a monitoring point rising from < 0.5 to > 100 cumecs. However, most rain events of similar magnitude are less intense, longer duration, and only raise AMD pH to ~ 4 with similar high discharges. Results presented here for Stockton confirm that it is the intensity of rain events on the hourly scale, rather than the total amount of rainwater delivered to the site, that governs the amount and composition of AMD generated during flood events. Stream discharge loads of dissolved iron and aluminium range from ~ 20 to 1000 kg/hour. Dissolved sulfate and acidity loads are typically ~ 500 kg/hour but can exceed 20 tonnes/hour in rain events.First flush effects observable elsewhere around the world involving peak metal loads following dry periods or seasonal changes are not obvious at Stockton due to the high and variable rainfall environment. Dissolved Fe concentrations may be limited in runoff waters by precipitation of jarosite and schwertmannite, especially when rainfall is sufficiently intense to raise pH to 4 or higher. These minerals are widespread in the exposed waste rock on site. Likewise, precipitation of alunite may occur as pH rises in rain events, but no field evidence for this has been observed. 相似文献