全文获取类型
收费全文 | 1489篇 |
免费 | 45篇 |
国内免费 | 9篇 |
专业分类
电工技术 | 123篇 |
综合类 | 4篇 |
化学工业 | 420篇 |
金属工艺 | 49篇 |
机械仪表 | 43篇 |
建筑科学 | 38篇 |
矿业工程 | 1篇 |
能源动力 | 61篇 |
轻工业 | 116篇 |
水利工程 | 4篇 |
石油天然气 | 4篇 |
无线电 | 101篇 |
一般工业技术 | 285篇 |
冶金工业 | 120篇 |
原子能技术 | 36篇 |
自动化技术 | 138篇 |
出版年
2023年 | 5篇 |
2022年 | 19篇 |
2021年 | 36篇 |
2020年 | 12篇 |
2019年 | 11篇 |
2018年 | 28篇 |
2017年 | 19篇 |
2016年 | 35篇 |
2015年 | 28篇 |
2014年 | 53篇 |
2013年 | 83篇 |
2012年 | 79篇 |
2011年 | 115篇 |
2010年 | 56篇 |
2009年 | 74篇 |
2008年 | 90篇 |
2007年 | 76篇 |
2006年 | 56篇 |
2005年 | 67篇 |
2004年 | 64篇 |
2003年 | 51篇 |
2002年 | 43篇 |
2001年 | 44篇 |
2000年 | 20篇 |
1999年 | 25篇 |
1998年 | 39篇 |
1997年 | 28篇 |
1996年 | 21篇 |
1995年 | 20篇 |
1994年 | 32篇 |
1993年 | 27篇 |
1992年 | 12篇 |
1991年 | 20篇 |
1990年 | 14篇 |
1989年 | 21篇 |
1988年 | 16篇 |
1987年 | 15篇 |
1986年 | 7篇 |
1985年 | 8篇 |
1984年 | 6篇 |
1983年 | 4篇 |
1982年 | 8篇 |
1981年 | 8篇 |
1980年 | 12篇 |
1979年 | 13篇 |
1978年 | 7篇 |
1977年 | 7篇 |
1976年 | 4篇 |
1974年 | 3篇 |
1972年 | 1篇 |
排序方式: 共有1543条查询结果,搜索用时 15 毫秒
991.
M Kami Y Kanda M Sasaki N Takeda Y Tanaka T Saito S Ogawa H Honda S Chiba K Mitani H Hirai Y Yazaki 《Canadian Metallurgical Quarterly》1998,21(7):721-723
Chronic GVHD is one of the major complications of BMT, involving a variety of organs, but rarely involving the genitourinary system. We report a patient who simultaneously developed extensive chronic GVHD and phimosis after BMT. From the clinical course and pathological findings, chronic GVHD was considered to be responsible for the phimosis. Despite intensive immunosuppressive therapy, the phimosis persisted. Phimosis is a rare complication after BMT, which may often remain neglected. Possibility of this complication should be considered in patients with chronic GVHD. 相似文献
992.
H Akazawa K Oda S Mitani T Yoshitaka K Asaumi H Inoue 《Canadian Metallurgical Quarterly》1998,80(4):636-640
Arthrogryposis multiplex congenita (AMC) is a rare disease with multiple joint contractures. It is widely believed that bilaterally dislocated hips should not be reduced since movement is satisfactory and open reduction has had poor results. Since 1977 we have performed a new method of open reduction using an extensive anterolateral approach on ten hips in five children with AMC. The mean age at surgery was 31.5 months (17 to 64) and the mean follow-up was 11.8 years (3.8 to 19.5). At the final follow-up all children walked without crutches or canes. Two managed independently, one required a long leg brace and two had short leg braces because of knee and/or foot problems. The clinical results were good in eight hips and fair in two and on the Severin classification seven hips were rated as good (group I or group II). We recommend the extensive anterolateral approach for unilateral or bilateral dislocation of the hip in children with arthrogryposis or developmental dislocation of the hip. 相似文献
993.
A tutorial survey of job-shop scheduling problems using genetic algorithms-I. representation 总被引:6,自引:0,他引:6
Job-shop scheduling problem (abbreviated to JSP) is one of the well-known hardest combinatorial optimization problems. During the last three decades, the problem has captured the interest of a significant number of researchers and a lot of literature has been published, but no efficient solution algorithm has been found yet for solving it to optimality in polynomial time. This has led to recent interest in using genetic algorithms (GAs) to address it. The purpose of this paper and its companion (Part II: Hybrid Genetic Search Strategies) is to give a tutorial survey of recent works on solving classical JSP using genetic algorithms. In Part I, we devote our attention to the representation schemes proposed for JSP. In Part II, we will discuss various hybrid approaches of genetic algorithms and conventional heuristics. The research works on GA/JSP provide very rich experiences for the constrained combinatorial optimization problems. All of the techniques developed for JSP may be useful for other scheduling problems in modern flexible manufacturing systems and other combinatorial optimization problems. 相似文献
994.
Yasuhiro Miyake Kiyoshi Chikamatsu Junichi Mizoguchi 《Journal of the Society for Information Display》2008,16(1):83-87
Abstract— A new electrical test method resulting in repeatable and unambiguous test results, which solves the drawback of the current lighting test used for the LCD cell‐manufacturing process, is proposed. This paper shows the basic scheme and the wide test coverage of this test method to detect defects in the cell process and gives an example of the actual measurement result. 相似文献
995.
Scattered light intensity distributions from microscratches on a silicon oxide wafer surface are simulated and analyzed for the purpose of microscratch sizing using a boundary element method (BEM)-based electromagnetic scattering simulator. At normal incidence, the characteristic scattered light resulting from microscratches appears in two symmetric regions of scattering angles, namely, at high and low angles. The scattered light intensities at high and low angles show characteristic fluctuation according to the depth and width variations of microscratches. It is found that the size of a microscratch can be obtained from the scattered light intensities at these characteristic angles. We propose microscratch sizing map which uses the detected light intensities to size the microscratches. Once the map is created, quick and easy categorization of microscratch size can be realized by collating the detected intensities with the map. The major advantage of using the map is the ability to measure simultaneously not only microscratch width but also depth. Generally, the depth cannot be obtained from an imaging system. Several experiments demonstrate the feasibility of our scheme and their results are in very good agreement with the simulation results. 相似文献
996.
To develop a functional capsule, which can be controlled to release materials entrapped in the inner aqueous space responding to light, partly crosslinked poly(acrylic acid)–poly-ethylenimine complex capsules containing a copolymer of acrylic acid and bis[4-(dimethylamino)phenyl](4-vinylphenyl)methyl leucohydroxide as an additional membrane component with radii of ca. 3 mm have been prepared. The triphenylmethane derivative on the copolymer dissociated into an ion pair under ultraviolet light irradiation in the weak alkaline region. Permeation of p-toluenesulfonate through the capsule membrane was enhanced significantly by the photoirradiation after a several minutes time lag under a weak alkaline condition. The photoinduced increase in permeability of the capsule was pH-dependent. The maximum effect of light on the permeability was observed near pH 8, whereas less enhancement was observed above or below the pH value. When the irradiation of the light was stopped, permeation of the permeant decreased. The photoresponsive permeability change of the capsule membrane can be carried out reversibly. © 1995 John Wiley & Sons, Inc. 相似文献
997.
Higher accuracy and more efficient production of large aperture glass lenses is increasingly required for high-resolution imaging devices. These glass lenses are typically manufactured by both ultra-precision grinding and polishing. However, prolonged polishing deteriorates the lens shape accuracy and diminishes productivity. In order to reduce the required amount of polishing or even obtain a polish-free fine surface, chemical action-assisted ultra-precision grinding using La-doped CeO2 slurry is proposed and its effectiveness is experimentally evaluated. The results show that the proposed grinding method successfully provides a high-quality surface comparable to a polished surface and results in five times higher productively than conventional grinding. 相似文献
998.
A Fast Simulation Method Using Overlapping Grids for Interactions between Smoke and Rigid Objects 总被引:1,自引:0,他引:1
Yoshinori Dobashi Yasuhiro Matsuda Tsuyoshi Yamamoto Tomoyuki Nishita 《Computer Graphics Forum》2008,27(2):477-486
Recently, many techniques using computational fluid dynamics have been proposed for the simulation of natural phenomena such as smoke and fire. Traditionally, a single grid is used for computing the motion of fluids. When an object interacts with a fluid, the resolution of the grid must be sufficiently high because the shape of the object is represented by a shape sampled at the grid points. This increases the number of grid points that are required, and hence the computational cost is increased. To address this problem, we propose a method using multiple grids that overlap with each other. In addition to a large single grid (a global grid) that covers the whole of the simulation space, separate grids (local grids) are generated that surround each object. The resolution of a local grid is higher than that of the global grid. The local grids move according to the motion of the objects. Therefore, the process of resampling the shape of the object is unnecessary when the object moves. To accelerate the computation, appropriate resolutions are adaptively‐determined for the local grids according to their distance from the viewpoint. Furthermore, since we use regular (orthogonal) lattices for the grids, the method is suitable for GPU implementation. This realizes the real‐time simulation of interactions between objects and smoke. 相似文献
999.
Zhengxin Liu Shinan Wang Naotaka Otogawa Yasuhito Suzuki Masato Osamura Yasuhiro Fukuzawa Teruhisa Ootsuka Yasuhiko Nakayama Hisao Tanoue Yunosuke Makita 《Solar Energy Materials & Solar Cells》2006,90(3):276-282
High-quality (1 1 0)/(1 0 1)-oriented epitaxial β-FeSi2 films were fabricated on Si (1 1 1) substrate by the sputtering method. The critical feature was the formation of a high-quality thin β-FeSi2 template buffer layer on Si (1 1 1) substrate at low temperature. It was demonstrated that the template is very important for the epitaxial growth of thick β-FeSi2 films and for the blocking of Fe diffusion into the Si at the β-FeSi2/Si interface. Hall effect measurements for β-FeSi2 films showed n-type conductivity, with residual electron concentration around 2.0 × 1017 cm−3 and mobility of 50–400 cm2/V s. A prototype thin-film solar cell was fabricated by depositing n-β-FeSi2 on p-Si (1 1 1). Under 100 mW/cm2 sunlight, an energy conversion efficiency of 3.7%, with an open-circuit voltage of 0.45 V, a short-circuit current density of 14.8 mA/cm2 and a fill factor of 0.55, was obtained. 相似文献
1000.
Ohno H Suzuki M Aoyama T Mitani K 《Shokuhin eiseigaku zasshi. Journal of the Food Hygienic Society of Japan》2003,44(6):332-336
An improved migration test was developed for determination of trace amounts of epichlorohydrin from internal can coatings. Eight kinds of sample cans, coated mainly with epoxy resin, for foods and beverages were prepared, and both their bodies and lids were tested for migration as follows. A body was filled with n-pentane and soaked for 2 hours at 25 degrees C. A lid was soaked in n-pentane (2 mL/cm2) for 2 hours at 25 degrees C. The test solution was analyzed by GC-FID and GC/MS using two DB-WAX capillary columns with different inside diameters. The limits of quantitation were 0.05 microgram/mL by GC-FID and 0.02 microgram/mL by GC/MS with selected ion monitoring. Recoveries of spiked epichlorohydrin were 99.9-104.5% at the level of 0.05 microgram/mL and 0.5 microgram/mL, with high precision. In this study, no epichlorohydrin was found to have migrated from any of the bodies and lids. 相似文献