全文获取类型
收费全文 | 561篇 |
免费 | 3篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 129篇 |
金属工艺 | 8篇 |
机械仪表 | 14篇 |
建筑科学 | 13篇 |
能源动力 | 4篇 |
轻工业 | 270篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 5篇 |
一般工业技术 | 43篇 |
冶金工业 | 28篇 |
自动化技术 | 47篇 |
出版年
2018年 | 6篇 |
2013年 | 86篇 |
2012年 | 7篇 |
2011年 | 10篇 |
2009年 | 5篇 |
2008年 | 8篇 |
2007年 | 9篇 |
2006年 | 8篇 |
2005年 | 7篇 |
2002年 | 9篇 |
2001年 | 6篇 |
2000年 | 5篇 |
1999年 | 9篇 |
1998年 | 5篇 |
1997年 | 22篇 |
1995年 | 12篇 |
1994年 | 10篇 |
1993年 | 5篇 |
1992年 | 8篇 |
1991年 | 7篇 |
1990年 | 10篇 |
1989年 | 5篇 |
1988年 | 10篇 |
1987年 | 18篇 |
1986年 | 12篇 |
1985年 | 8篇 |
1984年 | 10篇 |
1983年 | 12篇 |
1982年 | 7篇 |
1981年 | 5篇 |
1980年 | 11篇 |
1979年 | 8篇 |
1978年 | 9篇 |
1977年 | 9篇 |
1976年 | 8篇 |
1975年 | 11篇 |
1974年 | 7篇 |
1973年 | 6篇 |
1972年 | 5篇 |
1971年 | 6篇 |
1970年 | 9篇 |
1968年 | 22篇 |
1967年 | 21篇 |
1966年 | 7篇 |
1965年 | 6篇 |
1963年 | 4篇 |
1962年 | 5篇 |
1959年 | 6篇 |
1956年 | 4篇 |
1955年 | 4篇 |
排序方式: 共有565条查询结果,搜索用时 15 毫秒
11.
The precepts behind the macroscopic and microscopic quantizations of the electromagnetic field in a dielectric are discussed. Using the correspondence principle, it is demonstrated that the macroscopic quantization procedure leads to incorrect equations of motion of embedded two-level atoms. The fundamental nature of the Lorentz viewpoint of electrodynamics is discussed. 相似文献
12.
Horizontal directional solidification experiments were carried out with a monophasic Sn-2%Sb (mass fraction) alloy to analyze the influence of solidification thermal parameters on the morphology and length scale of the microstructure. Continuous temperature measurements were made during solidification at different positions along the length of the casting and these temperature data were used to determine solidification thermal parameters, including the growth rate (VL) and the cooling rate (TR). High cooling rate cells and dendrites are shown to characterize the microstructure in different regions of the casting, with a reverse dendrite-to-cell transition occurring for TR>5.0 K/s. Cellular (lc) and primary dendrite arm spacings (l1) are determined along the length of the directionally-solidified casting. Experimental growth laws relating lc and l1 to VL and TR are proposed, and a comparative analysis with results from a vertical upward directional solidification experiment is carried out. The influence of morphology and length scale of the microstructure on microhardness is also analyzed. 相似文献
13.
NESTOR VASQUEZLUIS LUIS SANCHEZ GEORGE E. KLINZING SHRIKANT DHODAPKAR 《Particulate Science and Technology》2013,31(2):119-127
Single-plug conveying systems have the advantage of being easy to handle and highly controllable. In industry, however, multi-plug conveying systems are the most common choice due to their high transporting capacity. In order to study a multi-plug industrial conveying system, the system parameters were varied along with the materials being conveyed. The responses obtained were compared to the single-plug laboratory system, noting differences and similarities. The pneumatic conveying system at an industrial facility consisted of a 0.01 m Schedule 10 aluminum pipe, approximately 100 m long. To measure the pressure at different points along the system, a total of seven transducers were installed, four air transducers and three flush transducers. This study also used a high-speed video camera to view the plugs as they passed through the transparent viewing port, providing more detailed information on the multi-plug conveying process. Three materials were tested at different superficial air velocities and solid mass flows. In each experiment all transducers took data with a sample rate of 1,000 Hz, giving a highly detailed overview of the conveying process. The analysis included plug velocity and plug size with respect to the superficial air velocity. The Mi model for plug-flow pressure drops was found to yield agreement with the data within ±25%. For this type of industrial operation, this agreement is considered acceptable. The visual observations recorded with the camera showed that there were conditions of stable plug formation as well as varying degrees of plug stability and integrity depending on the operational conditions. 相似文献
14.
CHARLES W. GARDINER 《Software》1996,26(10):1087-1096
Many programmers find that the logical structure of data defined in ASA.1 is simple enough, but the physical representation requires painfully careful attention to lots of detail. ASN.1 'compilers' which we had used required a programmer ot know the intricacies of both ASN.1 and the generated code. Furthermore those which generated 'C' code were prone to 'memory leaks' and produced bulky code. Two features of object orientiation led us to develop a code generator that procues 'C++'. First Class inheritance permits a small number of functions to operate on objects of any derived class. Second, the destructors of such objects can be designed to prevent memory leaks automatically. Our own use of the system shows that within a few days programmers withh no pair exposure to ASN.1 can start writing applications using only the ASN.1 specification for reference. The generated code is compact and well protected anainst memory leaks. This paper describes the capabilies of the code generator, the library of functions for handling all ASN.1 objects so generated, and the interior structure of these objects which allows the library functions to navigate any hierarchy. The las section discusses our experience in using the system. 相似文献
15.
On many machine tools the set-up times are sequence dependent; that is, the time to set-up for the new part is dependent upon the part for -which the machine is currently set-up. In scheduling lots on the machine, the set-up time is often a significant component of the total time required to complete each lot. Set-up times are frequently not available to the production scheduler, and when they are, they frequently are only averages which conceal the sequence dependency of the set-up times. In this paper, we first develop a procedure that classifies set-up operations and predicts the set-up times and we then develop a method for sequencing the jobs so as to minimize the total set-up time. An example using real world data is used to illustrate these procedures 相似文献
16.
17.
MICHAEL D. YOUNG STERLING BACKUS CHARLES DURFEE JEFF SQUIER 《Journal of microscopy》2013,249(2):83-86
A direct‐diode pumped Ti:sapphire femtosecond oscillator is used to perform multiphoton imaging for the first time. 相似文献
18.
Soluble peroxidase activity increased dramatically during the early stages of tomato fruit development, reaching a maximum at the mature-green stage. Ionically and covalently bound peroxidases were also observed, and the activities of these fractions increased steadily throughout fruit development. IAA (indoleacetic acid) oxidase activity was observed in both soluble and bound fractions and paralleled the peroxidase activity. Tissue homogenates from juvenile fruit caused an extended induction period in IAA oxidation reactions catalyzed by the purified tomato fruit peroxidase, suggesting the occurence of a high concentration of phenolic-type auxin protectors in this tissue. As the fruit developed, tissue homogenates showed a reduction in the amount of auxin protectors as the IAA oxidizing capacity of the fruit increased. 相似文献
19.
HENRY P. KIRCHNER ROBERT M. GRUVER RALPH E. WALKER 《Journal of the American Ceramic Society》1968,51(5):251-255
Low-expansion solid solution surface layers formed by reaction of Cr2 O3 and Al2 O3 were used to chemically strengthen alumina bodies. The surface layers were formed by packing the samples in Cr2 O3 powder and heating to high temperatures. Fluorides or chlorides were added to the packing material, leading to substantial additional improvement. The flexural strengths of the control samples were increased by refiring in the presence of the products of decomposition of the fluorides. At high concentrations of fluorides in the packing material, the outside dimensions and the weights of the samples decreased during the treatments. 相似文献
20.
Linear Thermal Expansion of Three Tungstates 总被引:2,自引:0,他引:2