全文获取类型
收费全文 | 14191篇 |
免费 | 380篇 |
国内免费 | 235篇 |
学科分类
工业技术 | 14806篇 |
出版年
2024年 | 8篇 |
2023年 | 85篇 |
2022年 | 146篇 |
2021年 | 207篇 |
2020年 | 212篇 |
2019年 | 153篇 |
2018年 | 176篇 |
2017年 | 203篇 |
2016年 | 216篇 |
2015年 | 423篇 |
2014年 | 683篇 |
2013年 | 743篇 |
2012年 | 708篇 |
2011年 | 1099篇 |
2010年 | 686篇 |
2009年 | 793篇 |
2008年 | 840篇 |
2007年 | 1147篇 |
2006年 | 1067篇 |
2005年 | 1018篇 |
2004年 | 804篇 |
2003年 | 764篇 |
2002年 | 533篇 |
2001年 | 360篇 |
2000年 | 288篇 |
1999年 | 234篇 |
1998年 | 211篇 |
1997年 | 156篇 |
1996年 | 157篇 |
1995年 | 111篇 |
1994年 | 99篇 |
1993年 | 75篇 |
1992年 | 57篇 |
1991年 | 72篇 |
1990年 | 41篇 |
1989年 | 46篇 |
1988年 | 34篇 |
1987年 | 19篇 |
1986年 | 14篇 |
1985年 | 20篇 |
1984年 | 17篇 |
1983年 | 9篇 |
1982年 | 12篇 |
1981年 | 8篇 |
1980年 | 6篇 |
1979年 | 9篇 |
1978年 | 8篇 |
1977年 | 8篇 |
1976年 | 12篇 |
1975年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
Yong-Seog?SeoEmail author Kwang-Sup?Song Sung-Kyu?Kang 《Korean Journal of Chemical Engineering》2003,20(5):819-828
A numerical investigation of a catalytically stabilized thermal (CST) combustor was conducted for a multichannel catalyst
bed, and both the catalyst bed and thermal combustor were simultaneously modeled. The numerical model handled the coupling
of the surface and gas reaction in the catalyst bed as well as the gas reaction in the thermal combustor. The behavior of
the catalyst bed was investigated at a variety of operating conditions, and location of the flame in the CST combustor was
investigated via an analysis of the distribution of CO concentration. Through parametric analyses of the flame position, it
was possible to derive a criterion to determine whether the flame is present in the catalyst bed or the thermal combustor
for a given inlet condition. The results showed that the maximum inlet temperature at which the flame is located in the thermal
combustor increased with increasing inlet velocity. 相似文献
102.
J.-M. Commenge T. Obein X. Framboisier V. Schanen M. Matlosz 《Chemical engineering science》2006,61(2):597-604
Industrial-scale performance of gas-liquid reactors can be difficult to optimise for very rapid or highly exothermic reactions. Microstructured reactors for laboratory measurements offer new opportunities for the study of these reactions by enabling precise heat management and fine control of reactor operating conditions. For accurate experimental study, characterisation of the flow conditions within these new reactor devices is essential.The present study examines experimental residence time distributions for the gas phase through a microstructured falling-film reactor, in order to develop an appropriate flow model for further study of gas-phase mass-transfer characteristics in the system. For the gas-phase residence time distribution experiments, the detection system involves a flow of oxygen containing ozone as a tracer gas with continuous monitoring of the concentration by UV-light absorption. The experimental results are used to model the flow behaviour in the gas volume over the gas-liquid contact zone as a series of continuous stirred tank reactors whose number is a simple function of the gas Reynolds number.The experimental results are compared with computational fluid dynamics calculations of the gas flow within the reactor. The comparison indicates a clear correlation of the flow model behaviour with the appearance of recirculation loops in the reaction chamber and the effect of the gas jet at the entrance of the gas-liquid contact zone. 相似文献
103.
Hyun Min Shim Joon Soo Lee Hong Yue Wang Seung Hak Choi Jeong Hoon Kim Hyung Taek Kim 《Korean Journal of Chemical Engineering》2007,24(3):537-541
The main purpose of the study was to develop a model using ASPEN and Excel simulation method to establish optimum CO2 separation process utilizing hollow fiber membrane modules to treat exhaust gas from LNG combustion. During the simulation,
optimum conditions of each CO2 separation scenario were determined while operating parameters of CO2 separation process were varied. The characteristics of hollow fibers membrane were assigned as 60 GPU of permeability and
25 of selectivity for the simulation. The simulation results illustrated that 4 stage connection of membrane module is required
in order to achieve over 99% of CO2 purity and 90% of recovery rate. The resulted optimum design and operation parameters throughout the simulation were also
correlated with the experimental data from the actual CO2 separation facility which has a capacity of 1,000 Nm3/day located in the Korea Research Institute of Chemical Technology. Throughout the simulation, the operating parameters of
minimum energy consumption were evaluated. Economic analysis of pilot scale of CO2 separation plant was done with the comparison of energy cost of CO2 recovery and equipment cost of the plant based on the simulation model.
This work was presented at the 6
th
Korea-China Workshop on Clean Energy Technology held at Busan, Korea, July 4–7, 2006. 相似文献
104.
针对以经验为主的混合流水车间设备购置策略所导致的生产不平衡问题,提出了一种木桶—贪婪算法。该算法在固定设备成本的约束下,以产线生产节拍最快为目标,利用木桶效应的补短板思路识别出瓶颈工序,并在此基础上针对产线内多种类产品瓶颈工序不一致的特性引入贪婪思想。然后,基于实际产线案例对比不同算法的求解结果,木桶—贪婪算法相比穷竭搜索算法以及改进遗传算法在求解质量和效率方面具有一定优势。最后,以实际产线为背景,利用Plant Simulation仿真进行产线改造前后对比,验证了提出的算法在实际生产中的可行性和有效性。 相似文献
105.
106.
《矿业科学技术学报(英文版)》2016,26(5):745-752
Data collected from truck payload management systems at various surface mines shows that the payload variance is significant and must be considered in analysing the mine productivity,energy consumption,greenhouse gas emissions and associated cost.Payload variance causes significant differences in gross vehicle weights.Heavily loaded trucks travel slower up ramps than lightly loaded trucks.Faster trucks are slowed by the presence of slower trucks,resulting in‘bunching’,production losses and increasing fuel consumptions.This paper simulates the truck bunching phenomena in large surface mines to improve truck and shovel systems’efficiency and minimise fuel consumption.The study concentrated on completing a practical simulation model based on a discrete event method which is most commonly used in this field of research in other industries.The simulation model has been validated by a dataset collected from a large surface mine in Arizona state,USA.The results have shown that there is a good agreement between the actual and estimated values of investigated parameters. 相似文献
107.
基于PR-11RⅢ级复合连杆滚动剪切机构运动学分析 总被引:1,自引:1,他引:0
楚志兵 《四川大学学报(工程科学版)》2015,47(6):165-171
通过对国内外现有的液压板材剪切机结构的原理分析,创新性地提出一种新型的单液压缸驱动的液压滚切式板材剪切机,获得PR-11RⅢ级杆组的复合连杆机构简化模型。以实现纯滚动为设计前提,利用闭环矢量法对该复合连杆滚切机构进行正运动学建模,给出机构的闭环矢量,推导其运动学方程,借助SIMLINK软件对其进行运动学仿真分析计算,获得上刀台各关键点的运动轨迹及主要衡量指标。以推广应用的某大型机械有限公司2000 mm单液压缸驱动的液压滚切式板材剪切机研发项目为依托,对剪切机构的运动轨迹进行运动学模拟仿真,结果表明上下剪刃重叠量和刀弧水平偏移量的模拟结果均符合实际生产要求,从而更进一步证实了该新型的单液压缸驱动的液压滚切式板材剪切机构设计的合理性与运动学模型的正确性。 相似文献
108.
针对电磁阀传统设计方法中,产品设计周期长、试制实验费用高等问题,本文采用有限元方法在产品设计初期对电磁阀的性能进行预测。首先,运用Ansoft Maxwell软件分别建立了电磁阀的三维与二维有限元模型,进行了磁场分析与电磁力计算,通过比较发现三维模型与二维模型计算结果与测试结果均吻合较好。最后,在二维模型的基础上,运用Maxwell软件的参数化设计功能进一步分析了不同初始间隙、不同驱动电压对电磁力的影响。结果表明,基于Maxwell的电磁阀有限元仿真能够在产品的设计初期快速地预测电磁阀的性能,为电磁阀的设计与优化提供理论指导。 相似文献
109.
针对独立电源系统中的无刷双馈发电机的特点,考虑到功率绕组和控制绕组的端电压随转速和负载的变化而变化,在无刷双馈电机d-q轴数学模型的基础上,建立了无刷双馈发电机在带载情况下的数学模型。并基于该数学模型,在matlab/simulink下建立了转速变化和负载变化的仿真模型,完成了其动态响应特性的研究。 相似文献
110.
无线传感器网络贪婪地理路由协议在动态环境中,采用自适应信标交换算法来自构建与维护邻居节点表,可以提高数据分组传送成功率,而且还可降低控制开销。本文具体描述了贪婪地理路由协议自适应信标交换算法在NS-2仿真平台的实现过程与部分细节,可以为贪婪地理路由协议的研究以及NS-2的仿真提供有益参考。 相似文献