全文获取类型
收费全文 | 1222篇 |
免费 | 0篇 |
专业分类
电工技术 | 15篇 |
化学工业 | 67篇 |
金属工艺 | 7篇 |
机械仪表 | 7篇 |
建筑科学 | 6篇 |
矿业工程 | 1篇 |
能源动力 | 5篇 |
轻工业 | 92篇 |
水利工程 | 1篇 |
石油天然气 | 9篇 |
无线电 | 87篇 |
一般工业技术 | 64篇 |
冶金工业 | 814篇 |
原子能技术 | 7篇 |
自动化技术 | 40篇 |
出版年
2021年 | 5篇 |
2019年 | 3篇 |
2018年 | 3篇 |
2015年 | 3篇 |
2014年 | 9篇 |
2013年 | 26篇 |
2012年 | 6篇 |
2011年 | 11篇 |
2010年 | 8篇 |
2009年 | 10篇 |
2008年 | 13篇 |
2007年 | 19篇 |
2006年 | 14篇 |
2005年 | 11篇 |
2004年 | 7篇 |
2003年 | 17篇 |
2002年 | 10篇 |
2001年 | 16篇 |
2000年 | 17篇 |
1999年 | 36篇 |
1998年 | 211篇 |
1997年 | 146篇 |
1996年 | 87篇 |
1995年 | 64篇 |
1994年 | 44篇 |
1993年 | 56篇 |
1992年 | 26篇 |
1991年 | 15篇 |
1990年 | 20篇 |
1989年 | 24篇 |
1988年 | 23篇 |
1987年 | 17篇 |
1986年 | 19篇 |
1985年 | 19篇 |
1984年 | 6篇 |
1983年 | 11篇 |
1982年 | 4篇 |
1981年 | 11篇 |
1980年 | 13篇 |
1979年 | 9篇 |
1978年 | 10篇 |
1977年 | 31篇 |
1976年 | 60篇 |
1975年 | 8篇 |
1974年 | 6篇 |
1973年 | 7篇 |
1971年 | 3篇 |
1970年 | 3篇 |
1969年 | 4篇 |
1965年 | 3篇 |
排序方式: 共有1222条查询结果,搜索用时 0 毫秒
31.
32.
33.
34.
John A. Swanson 《Computers & Structures》1977,7(2):291-294
One of the major new developments in computing technology is the mini-computer. This paper presents the results of the implementation of the ANSYS computer program (a large-scale structural analysis system) on a mini-computer.The implementation of ANSYS started with an evaluation of the existing and proposed mini-computer hardware and software systems, relative to a set of criteria derived from the structural software requirements.After benchmarking several systems to compare the claimed performances with the actual performance, the system which most nearly met the requirements for the ANSYS program was selected and ordered.The configuration chosen for this development machine is illustrated and variations from the development configuration which would be desirable for a production environment are discussed.The results of the implementation of ANSYS on the selected mini-computer system are presented. Included in the presentation are run times, run costs, accuracy of results and computer storage requirements.Finally, this paper discusses the future directions which will be pursued in this development effort. Included are discussions of the interface between the mini-computer and a larger central computer, the limits on problem size imposed by core memory and solution time and suggestions for the improvement of the performance of structural problems in a mini-computer environment. 相似文献
35.
The near-IR absorption of a heavily injected silicon p-i-n diode has been measured. This is thought to be the first comprehensive measurement of the free-carrier absorption of a hole-electron plasma, and it behaves as expected with temperature, injection level and wavelength.
However, the absolute value of the absorption is higher than can be accounted for by ionized impurity scattering mechanisms by a factor of about 2. 相似文献
36.
37.
C. O. Swanson 《Journal of the American Ceramic Society》1923,6(12):1248-1260
The term laterite means a red rock or red earth deposit. Laterites are formed by the decomposition of different kind of rocks, under conditions yielding aluminum and iron hydroxides. The different theories of origin are discussed, as well as the chemical process of laterization, and the geographic distribution of this peculiar type of clay. 相似文献
38.
J Permert J Larsson GT Westermark MK Herrington L Christmanson PM Pour P Westermark TE Adrian 《Canadian Metallurgical Quarterly》1994,330(5):313-318
Population-based psychiatric admission rates vary across geographic areas, but reasons for this variation are unknown. Insofar as Community Mental Health Centers (CMHCs) provide outpatient services that may deter the need for hospitalization, the presence and structural characteristics of CMHCs may have an impact on a population's psychiatric admission rates. This study uses small area analysis to examine how general hospital psychiatric admission rates are associated with CMHC characteristics. Based on a survey of all CMHCs in Iowa and corresponding small area variation data, it was found that population admission rates were higher in areas closer to the CMHC and lower in outlying catchment areas, adjusting for age, sex, and urban/rural differences in populations. There was little evidence that differences in staffing and service variables influenced admission rates, although greater CMHC staff coverage by social workers and psychiatric residents was associated with lower admission rates. The results suggest that CMHCs do not lower an area's hospitalization rate, and in fact, the presence of CMHCs may promote a "supplier-induced demand" phenomenon of higher admissions. 相似文献
39.
Dan Swanson 《EDPACS》2019,59(2):1-5
As I have discussed in past articles, internal audit efforts must be risk-based and contribute to the long-term assurance needs of the organization and its board. A formal risk-assessment audit must be completed at least annually and the results of that assessment should direct audit priorities. Periodic updates throughout the year are also highly recommended. Over time, a focus on short-term results (quarterly financial results, meeting current regulatory requirements, etc.) has driven the priorities of management and consequently the organization toward a short-term perspective. Similarly, internal auditing’s efforts has commonly moved toward this short-term focus, boiling down priorities to whichever audits the company needs to complete in the immediate quarter or two. During the challenging business environment period some would say it is not a good time to refocus sights on the long-term horizon. I disagree. For example, knowing what the organization want to achieve in the next two to five years, and what does it need to do to get there, is critical to success! Certainly, each organization will have different goals, objectives, issues, and challenges, and no single “standard” long-term internal audit plan will work; but I took a shot at it anyway, and present the results in this article. 相似文献
40.
116 of the 162 Occupational scales of the 1981 revision of the Strong-Campbell Interest Inventory (SCII) were constructed with new criterion samples. This study (a) assessed the concurrent and predictive validity of the revised SCII and explored its usefulness for predicting college majors (Exp I) and (b) examined the differential effect of stable and unstable interests during college on the validity of the SCII (Exp II). Data were analyzed for 354 females and 261 males who completed the SCII as college freshmen; 81% were still enrolled in school at the time of this study. Results indicate that the revised SCII can be used to predict college majors, having concurrent and predictive validity comparable to previous forms of the SCII. It was slightly more predictive for females than for males. Findings also show that the majority of Ss had stable interests during their college careers. The revised SCII was significantly more predictive of college majors for Ss who were satisfied with their majors or who had stable interests than it was for those who were dissatisfied or had unstable interests. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献