全文获取类型
收费全文 | 1108篇 |
免费 | 27篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 9篇 |
综合类 | 17篇 |
化学工业 | 65篇 |
金属工艺 | 25篇 |
机械仪表 | 24篇 |
建筑科学 | 640篇 |
矿业工程 | 10篇 |
能源动力 | 28篇 |
轻工业 | 52篇 |
水利工程 | 8篇 |
石油天然气 | 2篇 |
无线电 | 27篇 |
一般工业技术 | 99篇 |
冶金工业 | 33篇 |
原子能技术 | 3篇 |
自动化技术 | 94篇 |
出版年
2023年 | 10篇 |
2022年 | 5篇 |
2021年 | 17篇 |
2020年 | 17篇 |
2019年 | 6篇 |
2018年 | 23篇 |
2017年 | 7篇 |
2016年 | 12篇 |
2015年 | 12篇 |
2014年 | 22篇 |
2013年 | 97篇 |
2012年 | 21篇 |
2011年 | 28篇 |
2010年 | 21篇 |
2009年 | 39篇 |
2008年 | 27篇 |
2007年 | 13篇 |
2006年 | 15篇 |
2005年 | 50篇 |
2004年 | 39篇 |
2003年 | 38篇 |
2002年 | 49篇 |
2001年 | 31篇 |
2000年 | 45篇 |
1999年 | 43篇 |
1998年 | 44篇 |
1997年 | 38篇 |
1996年 | 42篇 |
1995年 | 38篇 |
1994年 | 43篇 |
1993年 | 29篇 |
1992年 | 43篇 |
1991年 | 31篇 |
1990年 | 22篇 |
1989年 | 39篇 |
1988年 | 24篇 |
1987年 | 18篇 |
1985年 | 6篇 |
1984年 | 3篇 |
1983年 | 4篇 |
1980年 | 6篇 |
1978年 | 2篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1967年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有1136条查询结果,搜索用时 162 毫秒
91.
G. L. Harding BSc PhD B. Window BSc PhD R. Gammon B.Tech PhD MInstP MIEAust MAIE 《国际自然能源杂志》2013,34(4):171-180
The design of evacuated collectors developed in various laboratories is reviewed and the research and development work on all glass evacuated collector at the University of Sydney is discussed In detail Long-term comparative test data for flat plate and evacuated collectors and the projected economics of large volume manufacture of all-glass collectors indicate the viability of evacuated collectors for applications such as domestic water heating. 相似文献
92.
94.
This study reports an experiment to investigate the feasibility of a passive heating roof-pond system on an existing room in the cold winter conditions of Riyadh, Saudi Arabia. Statistical analyses of data recorded during the winter season of 1996–97, are carried out to evaluate the thermal peformance of the proposed system. Total effective heating and the heating power of the roof pond system are computed and analysed. Results indicate that the roof-pond system is capable of maintaining warm indoor air temperature conditions. The statistical formulae for this system are presented and used to estimate the indoor daily average air Dry Bulb Temperature (DBTAvg-indoor] created by the system. Validation of the proposed formulae is also presented. 相似文献
95.
96.
Decomposition of steam under a chemical driving force at moderate temperatures offers a simple and economical way to generate hydrogen. A significant amount of hydrogen can be generated and separated by splitting steam and removing the oxygen using Gd0.2Ce0.8O1.9−δ (GDC)–Gd0.08Sr0.88Ti0.95Al0.05O3±δ (GSTA) mixed oxygen ionic and electronic conducting membranes. Hydrogen generation experiments for the self-supported thick membranes and porous supported thin membranes were conducted at different oxygen partial pressure gradients across the membrane established using H2–H2O mixture gas. Experimental results indicate that the hydrogen generation from steam using GDC–GSTA MIEC membranes at elevated temperatures is mainly controlled by the bulk diffusion of oxygen for the self-supported thick membranes, while the permeation process for the porous supported thin membranes is mixed controlled, i.e. the hydrogen generation/oxygen permeation process is controlled by the surface exchange reactions and bulk diffusion of oxygen through the MIEC membrane. A mathematical model for the calculation of the area specific hydrogen generation rate is proposed in this paper based on the measured oxygen partial pressures, gas compositions, and gas flow rates of the inlet and outlet gases on feed side of the membrane, as well as the permeation area of the membrane. 相似文献
97.
98.
During recent years, water management in The Netherlands has been broadening its scope by: (a) including aspects of economics, sociology and physical planning, and (b) introducing interactive policy making; this paper illustrates these developments using the Westerschelde estuary as an example. The Westerschelde strategy aims at optimizing the multi-national use of this estuary. The main functions are navigation and ecology, and the paper shows how these functions can be combined. An interactive management model, the 'COSMO-Westerschelde'is described, which assists decision makers in comparing strategies for estuarine management under different scenarios. 相似文献
99.
C. Hale BSc K. Kaur BSc PhD N. Jones BSc B. Oliver 《Water and Environment Journal》2005,19(4):376-383
Llangefni WwTW receives discharge from the rural town of Llangefni and the local industrial estate and to date this is the first and only BNR plant in Wales. The consents from March 2003 included a reduction in ammonia (NH4 _N) to 1.5 mg/l, suspended solids to 20 mg/l (SS) and Biological Oxygen Demand (BOD) to 7 mg/l and included a new Phosphate (PO4 _P) standard of 2 mg/l. The process selected to meet the new consents was Biological Nutrient Removal (BNR) and was unusual as it was for a small, rural wastewater treatment plant that receives about 26% of its flow from an industrial estate.
During commissioning, the plant produced an average phosphate concentration of 1.0 mg/l and an ammonia concentration of 0.7 mg/l. It was confirmed that to achieve consistent phosphate removal a BOD:P ratio greater than 20:1 is required along with a high VFA (Volatile Fatty Acids) concentration of 200–300 mg/l. 相似文献
During commissioning, the plant produced an average phosphate concentration of 1.0 mg/l and an ammonia concentration of 0.7 mg/l. It was confirmed that to achieve consistent phosphate removal a BOD:P ratio greater than 20:1 is required along with a high VFA (Volatile Fatty Acids) concentration of 200–300 mg/l. 相似文献
100.
G. D JOB BEng PhD R. TRENGOVE BSc CEng MIEE G. J REALEY BSc DIS CEng MIChemE 《Water and Environment Journal》1995,9(3):257-263
Ultraviolet radiation has been shown to be effective for disinfecting secondary effluents, and the National Rivers Authority has given conditional approval for its use at sites where disinfection can be justified.
This paper describes the findings of disinfection trials on five different sewage works' effluents using low-pressure ultraviolet systems. The study examines and compares the disinfection performance of clean units and their deterioration in performance due to fouling effects. Conclusions are drawn on the effectiveness of ultraviolet disinfection in the removal of pathogens and pathogen surrogates. 相似文献
This paper describes the findings of disinfection trials on five different sewage works' effluents using low-pressure ultraviolet systems. The study examines and compares the disinfection performance of clean units and their deterioration in performance due to fouling effects. Conclusions are drawn on the effectiveness of ultraviolet disinfection in the removal of pathogens and pathogen surrogates. 相似文献