全文获取类型
收费全文 | 1814篇 |
免费 | 33篇 |
国内免费 | 85篇 |
专业分类
电工技术 | 55篇 |
综合类 | 48篇 |
化学工业 | 140篇 |
金属工艺 | 62篇 |
机械仪表 | 78篇 |
建筑科学 | 4篇 |
矿业工程 | 10篇 |
能源动力 | 103篇 |
武器工业 | 12篇 |
无线电 | 880篇 |
一般工业技术 | 358篇 |
冶金工业 | 13篇 |
原子能技术 | 37篇 |
自动化技术 | 132篇 |
出版年
2023年 | 15篇 |
2022年 | 18篇 |
2021年 | 19篇 |
2020年 | 27篇 |
2019年 | 13篇 |
2018年 | 12篇 |
2017年 | 33篇 |
2016年 | 29篇 |
2015年 | 39篇 |
2014年 | 71篇 |
2013年 | 65篇 |
2012年 | 49篇 |
2011年 | 102篇 |
2010年 | 74篇 |
2009年 | 84篇 |
2008年 | 79篇 |
2007年 | 88篇 |
2006年 | 110篇 |
2005年 | 65篇 |
2004年 | 56篇 |
2003年 | 56篇 |
2002年 | 55篇 |
2001年 | 38篇 |
2000年 | 57篇 |
1999年 | 70篇 |
1998年 | 104篇 |
1997年 | 95篇 |
1996年 | 104篇 |
1995年 | 59篇 |
1994年 | 29篇 |
1993年 | 27篇 |
1992年 | 37篇 |
1991年 | 34篇 |
1990年 | 40篇 |
1989年 | 25篇 |
1988年 | 36篇 |
1987年 | 7篇 |
1986年 | 3篇 |
1985年 | 5篇 |
1984年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有1932条查询结果,搜索用时 15 毫秒
21.
用电流控制液相外延(CCLPE)方法首次在(100)InP衬底上成功地生长出In1-xGaxAsyP1-y(0.30<x<0.47,0.70<y<0.96)外延层,并对外延层特性进行了详细研究,提出在InP衬底上生长电外延层的机理,推导出生长动力学的理论模型,该模型与上述实验结果十分吻合。 相似文献
22.
Z. J. Pei S. Kassir Milind Bhagavat Graham R. Fisher 《International Journal of Machine Tools and Manufacture》2004,44(2-3):299-306
Silicon is the primary semiconductor material used to fabricate microchips. A series of processes are required to manufacture high-quality silicon wafers. Surface grinding is one of the processes used to flatten wire-sawn wafers. A major issue in grinding of wire-sawn wafers is reduction and elimination of wire-sawing induced waviness. Results of finite element analysis have shown that soft-pad grinding is very effective in reducing the waviness. This paper presents an experimental investigation into soft-pad grinding of wire-sawn silicon wafers. Wire-sawn wafers from a same silicon ingot were used for the study to ensure that these wafers have similar waviness. These wafers were ground using two different soft pads. As a comparison, some wafers were also ground on a rigid chuck. Effectiveness of soft-pad grinding in removing waviness has been clearly demonstrated. 相似文献
23.
The coupled photocatalyst WO3/TiO2 is prepared by ball milling by doping WO3 into TiO2 and using H2O solution as disperser. The coupled photocatalyst WO3/TiO2 is characterized by UV–VIS diffuse reflection spectrum, X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD) and Transmission electron microscopy (TEM). The results show that the optimum percentage of WO3 doped is 3% and that the photocatalytic activity of the coupled WO3/TiO2 photocatalyst is much higher than that of TiO2 and WO3–TiO2 with no ball milling. Compared with TiO2, the photoexcited wavelength range of the WO3/TiO2 photocatalyst red-shifts about 50 nm, and the light absorption intensity is also improved. The crystal phase of TiO2 is not changed and new crystal phases are not found during the process of ball milling. WO3 and TiO2 coupled highly, forming the WO3/TiO2 photocatalyst. The increased photocatalytic activity of the coupled photocatalyst may be attributed to the enhance charge separation efficiency and the extend wavelength range of photoexcitation. 相似文献
24.
Scanning electron microscope (SEM) station is one of the major quality control tasks in wafer manufacturing process. During the process of examining defects on a screen for a certain period of time, SEM inspectors frequently complain about visual fatigue problems. The purpose of the study was to evaluate the effect of wafer‐coating condition (noncoating treatment and gold‐coating treatment) and liquid crystal display (LCD) monitor size (14‐inch and 19‐inch monitor) from the aspects of objective visual fatigue measures (NPA and CFF), subjective eye fatigue rating, and inspection performance. Twelve SEM inspectors participated in this experiment. The results indicated that the treatment of gold‐coating wafer showed significant difference on reducing objective visual fatigue in NPA and CFF change. Using a 19‐inch LCD monitor also demonstrated the effect on reducing eye fatigue as well as improving inspection performance. The improvement of using a gold‐coating treatment wafer and a 19‐inch LCD monitor to reduce SEM inspectors' visual fatigue and to increase inspection performance is thus recommended. © 2012 Wiley Periodicals, Inc. 相似文献
26.
镍阳极氧化膜形成和破坏过程的光电化学响应 总被引:2,自引:0,他引:2
测定了镍表面阳极氧化膜在pH=8.4硼砂-硼酸缓冲溶液中不同电位下的光电流响应。基于阻抗测量结果的计算表明,钝化膜的平带电位和载流子密度分别为-0.68V和1.3×10(20)cm(-3)。对钝化膜和高价氧化膜在形成、生长和破坏过程中的光电流变化进行了现场监测。 相似文献
27.
S. Chidambaram Z. J. Pei S. Kassir 《International Journal of Machine Tools and Manufacture》2003,43(7):463
Fine grinding of silicon wafers is a patented technology to manufacture super flat semiconductor wafers cost-effectively. Two papers on fine grinding were previously published in this journal, one discussed its uniqueness and special requirements, and the other presented the results of a designed experimental investigation. As a follow up, this paper presents a study aiming at overcoming one of the technical barriers that have hindered the widespread application of this technology, namely, the difficulty and uncertainty in chuck preparation. Although the chuck shape is critically important in fine grinding, there are no standard procedures for its preparation. Furthermore, the information on the relation between the set-up parameters and the resulting chuck shape is not readily available. In this paper, a mathematical model for the chuck shape is first developed. Then the model is used to predict the relations between the chuck shape and the set-up parameters. Finally, the results of the pilot experiments to verify the model are discussed. 相似文献
28.
Rene DriesselLars Mönch 《Computers & Industrial Engineering》2011,61(2):336-345
In this paper, we discuss a scheduling problem for jobs on identical parallel machines. Ready times of the jobs, precedence constraints, and sequence-dependent setup times are considered. We are interested in minimizing the performance measure total weighted tardiness that is important for achieving good on-time delivery performance. Scheduling problems of this type appear as subproblems in decomposition approaches for large scale job shops with automated transport of the jobs as, for example, in semiconductor manufacturing. We suggest several variants of variable neighborhood search (VNS) schemes for this scheduling problem and compare their performance with the performance of a list based scheduling approach based on the Apparent Tardiness Cost with Setups and Ready Times (ATCSR) dispatching rule. Based on extensive computational experiments with randomly generated test instances we are able to show that the VNS approach clearly outperforms heuristics based on the ATCSR dispatching rule in many situations with respect to solution quality. When using the schedule obtained by ATCSR as an initial solution for VNS, then the entire scheme is also fast and can be used as a subproblem solution procedure for complex job shop decomposition approaches. 相似文献
29.
Hiroyuki YamauraAuthor VitaeYuji IwasakiAuthor Vitae Shinsuke HiraoAuthor VitaeHidenori YahiroAuthor Vitae 《Sensors and actuators. B, Chemical》2011,153(2):465-467
The CO sensing property of CuO-loaded SnO2-In2O3 sensor was investigated in a reducing atmosphere. The sensor response to CO for CuO/SnO2-In2O3 (8/2) was much higher than that for CuO/SnO2 in the range of 200-1000 ppm of CO concentration. Such a high sensor response of CuO/SnO2-In2O3 may originate from the high dispersion of CuO playing a role as sensing site. 相似文献
30.
Implementing efficient scheduling and dispatching policies is a critical means to gain competitiveness for modern semiconductor manufacturing systems. In contemporary global market, a successful semiconductor manufacturer has to excel in multiple performance indices, consequently qualified scheduling approaches should provide efficient and holistic management of wafer products, information and manufacturing resources and make adaptive decisions based on real-time processing status to reach an overall optimized system performance. To cope with this challenge, a timed extended object-oriented Petri nets (EOPNs) based multiple-objective scheduling and real-time dispatching approach is proposed in this paper. Four performance objectives pursued by semiconductor manufacturers are integrated into a priority-ranking algorithm that serves as the initial scheduling guidance, and then all wafer lots will be dynamically dispatched by the hybrid real-time dispatching control system. A set of simulation experiments validate the proposed multiple-objective scheduling and real-time dispatching algorithm may achieve satisfactory performances. 相似文献