全文获取类型
收费全文 | 10626篇 |
免费 | 1132篇 |
国内免费 | 238篇 |
专业分类
电工技术 | 65篇 |
综合类 | 1119篇 |
化学工业 | 3824篇 |
金属工艺 | 117篇 |
机械仪表 | 154篇 |
建筑科学 | 2063篇 |
矿业工程 | 202篇 |
能源动力 | 812篇 |
轻工业 | 2105篇 |
水利工程 | 222篇 |
石油天然气 | 346篇 |
武器工业 | 6篇 |
无线电 | 15篇 |
一般工业技术 | 236篇 |
冶金工业 | 580篇 |
原子能技术 | 42篇 |
自动化技术 | 88篇 |
出版年
2024年 | 55篇 |
2023年 | 160篇 |
2022年 | 300篇 |
2021年 | 353篇 |
2020年 | 397篇 |
2019年 | 353篇 |
2018年 | 309篇 |
2017年 | 343篇 |
2016年 | 432篇 |
2015年 | 352篇 |
2014年 | 659篇 |
2013年 | 637篇 |
2012年 | 851篇 |
2011年 | 842篇 |
2010年 | 637篇 |
2009年 | 669篇 |
2008年 | 546篇 |
2007年 | 693篇 |
2006年 | 669篇 |
2005年 | 527篇 |
2004年 | 404篇 |
2003年 | 352篇 |
2002年 | 240篇 |
2001年 | 172篇 |
2000年 | 157篇 |
1999年 | 127篇 |
1998年 | 84篇 |
1997年 | 75篇 |
1996年 | 62篇 |
1995年 | 64篇 |
1994年 | 48篇 |
1993年 | 66篇 |
1992年 | 57篇 |
1991年 | 50篇 |
1990年 | 25篇 |
1989年 | 31篇 |
1988年 | 30篇 |
1987年 | 29篇 |
1986年 | 32篇 |
1985年 | 42篇 |
1984年 | 29篇 |
1983年 | 16篇 |
1982年 | 4篇 |
1981年 | 7篇 |
1980年 | 3篇 |
1951年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
LUO Sheng-lian YUAN Lin CHAI Li-yuan MIN Xiao-bo WANG Yun-yan FANG Yan WANG Pu 《中国有色金属学会会刊》2006,16(6)
1Introduction Waste activated sludge is the by-product of sewage treated by activated sludge process.According to incomplete statistic,in China sewage discharge amount is4.474×107m3/d[1],and there are more than100sewage treatment plants with different sc… 相似文献
122.
HUOGuangsheng SUNPeimei LIHonggui LIYunjiao ZHAOZhongwei SUNZhaoming LIUMaosheng 《稀有金属(英文版)》2004,23(2):115-119
The effect of different decomposition conditions on tungsten recovery for scheelite concentrate has been examined. The results show that tungsten recovery can be more than 98% under decomposing conditions as follows: the amount of caustic soda is 2.2 and 3.2 times of theoretical respectively, ratio of water and ore is 0.7-0.8, temperature is 160℃, and preservation time is 2.0 h for scheelite concentrate (63.21% WO3) and low grade scheelite concentrate (55.17% WO3). 相似文献
123.
对筛分技术应用于城市河道污泥进行探索研究,在对城市河道污泥的工程特性分析的基础上,对不同的筛分设备用于城市河道污泥进行全面分析,并将筛分技术应用于工程实践中,取得了良好的效果,为城市河道污泥预处置中遇到的难题提供了良好借鉴。 相似文献
124.
In this work, we discuss the application of multivariable predictive control for the activated sludge process in a full-scale municipal wastewater treatment plant. Emphasis is given to the selection of a control configuration that contributes to minimising the economic costs while improving the removal efficiency of the nitrogen compounds. For this task, a simple dynamic matrix control algorithm is favoured for controlling the nitrogen concentrations at the end of the biological process. The behaviour of the activated sludge process is reproduced in a commercial simulator that acts as a real-time testing platform and that is also used for identifying the multivariable input–output models for the predictive controller. For demonstrating the effectiveness of the proposed approach, different control configurations are considered and compared against the aeration control strategies currently used at the plant. Based on the simulation results, this work shows the potentiality of the dynamic matrix control which is able to decrease the energy consumption costs and, at the same time, reduce the ammonia peaks and nitrate concentration in the effluent. 相似文献
125.
This paper presents an optimal control law policy for maximizing biogas production of anaerobic digesters. In particular, using a simple model of the anaerobic digestion process, we derive a control law to maximize the biogas production over a period T using the dilution rate as the control variable. Depending on initial conditions and constraints on the actuator (the dilution rate D(·)), the search for a solution to the optimal control problem reveals very different levels of difficulty. In the present paper, we consider that there are no severe constraints on the actuator. In particular, the interval in which the input flow rate lives includes the value which allows the biogas to be maximized at equilibrium. For this case, we solve the optimal control problem using classical tools of differential equations analysis. Numerical simulations illustrate the robustness of the control law with respect to several parameters, notably with respect to initial conditions. We use these results to show that the heuristic control law proposed by Steyer et al., 1999 [20] is optimal in a certain sense. The optimal trajectories are then compared with those given by a purely numerical optimal control solver (i.e. the “BOCOP” toolkit) which is an open-source toolbox for solving optimal control problems. When the exact analytical solution to the optimal control problem cannot be found, we suggest that such numerical tool can be used to intuiter optimal solutions. 相似文献
126.
污水处理厂污泥厌氧消化优化设计与运行探讨 总被引:1,自引:0,他引:1
对国内典型的污水处理厂污泥厌氧消化系统进行调研发现,厌氧消化系统的运行管理尚存在诸多问题。在总结白龙港污水处理厂污泥厌氧消化调试与运行管理经验的基础上,针对厌氧消化工艺存在的普遍性问题,提出了厌氧消化系统设计和运行管理方面的建议,以促进工艺设计优化,提高运行管理水平。 相似文献
127.
《工程(英文)》2018,4(4):574-580
Organic solid and liquid wastes contain large amounts of energy, nutrients, and water, and should not be perceived as merely waste. Recycling, composting, and combustion of non-recyclables have been practiced for decades to capture the energy and values from municipal solid wastes. Treatment and disposal have been the primary management strategy for wastewater. As new technologies are emerging, alternative options for the utilization of both solid wastes and wastewater have become available. Considering the complexity of the chemical, physical, and biological properties of these wastes, multiple technologies may be required to maximize the energy and value recovery from the wastes. For this purpose, biorefining tends to be an appropriate approach to completely utilize the energy and value available in wastes. Research has demonstrated that non-recyclable waste materials and bio-solids can be converted into usable heat, electricity, fuel, and chemicals through a variety of processes, and the liquid waste streams have the potential to support crop and algae growth and provide other energy recovery and food production options. In this paper, we propose new biorefining schemes aimed at organic solid and liquid wastes from municipal sources, food and biological processing plants, and animal production facilities. Four new breakthrough technologies—namely, vacuum-assisted thermophilic anaerobic digestion, extended aquaponics, oily wastes to biodiesel via glycerolysis, and microwave-assisted thermochemical conversion—can be incorporated into the biorefining schemes, thereby enabling the complete utilization of those wastes for the production of chemicals, fertilizer, energy (biogas, syngas, biodiesel, and bio-oil), foods, and feeds, and resulting in clean water and a significant reduction in pollutant emissions. 相似文献
128.
《Advanced Powder Technology》2023,34(1):103908
The production of crab meatballs generates large amount of crab shell waste, it is therefore necessary to develop a green, economical and environmentally friendly process to vaporize the waste. This study was aimed at investigating the applicability of microwave heating combined with ultrasonic field-assisted alkaline protease (MUSED) (50 ℃, pH = 9.0, 14025.67 U/g, 4.21 h and liquid/material = 14.41:1) for pretreatment of ball-milled crab shells. The ball milling efficiency of the crab shell powder pretreated by MUSED was observed to increase by 50 % compared to the control group, with the final average particle size of D4 = 4.88 ± 0.20 um. High calcium solubility and low energy consumption of the ball-milled powder increased dietary calcium bioavailability and reduced the potential for high calorie intake. The addition of 6 % (w/w) crab shell powder treated by MUSED improved the texture of the crab meatballs (CM-D4) and gave the product enhanced crab flavor relative to the control group. Moreover, the lower cooking loss of CM-D4 resulted in significant retention of nutrients (p < 0.05). The crab shell powder treated by MUSED method was more efficient in ball milling, which improved the quality of crab meatballs while relieving environmental pressure. 相似文献
129.
130.