全文获取类型
收费全文 | 5761篇 |
免费 | 162篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 58篇 |
综合类 | 5篇 |
化学工业 | 1049篇 |
金属工艺 | 116篇 |
机械仪表 | 75篇 |
建筑科学 | 217篇 |
矿业工程 | 4篇 |
能源动力 | 89篇 |
轻工业 | 534篇 |
水利工程 | 31篇 |
石油天然气 | 6篇 |
武器工业 | 1篇 |
无线电 | 377篇 |
一般工业技术 | 907篇 |
冶金工业 | 1954篇 |
原子能技术 | 58篇 |
自动化技术 | 443篇 |
出版年
2022年 | 43篇 |
2021年 | 65篇 |
2020年 | 46篇 |
2019年 | 51篇 |
2018年 | 75篇 |
2017年 | 75篇 |
2016年 | 100篇 |
2015年 | 100篇 |
2014年 | 113篇 |
2013年 | 162篇 |
2012年 | 159篇 |
2011年 | 190篇 |
2010年 | 182篇 |
2009年 | 147篇 |
2008年 | 179篇 |
2007年 | 147篇 |
2006年 | 157篇 |
2005年 | 112篇 |
2004年 | 117篇 |
2003年 | 128篇 |
2002年 | 108篇 |
2001年 | 126篇 |
2000年 | 111篇 |
1999年 | 150篇 |
1998年 | 596篇 |
1997年 | 374篇 |
1996年 | 267篇 |
1995年 | 147篇 |
1994年 | 132篇 |
1993年 | 146篇 |
1992年 | 64篇 |
1991年 | 52篇 |
1990年 | 69篇 |
1989年 | 66篇 |
1988年 | 46篇 |
1987年 | 49篇 |
1986年 | 48篇 |
1985年 | 41篇 |
1984年 | 37篇 |
1983年 | 42篇 |
1982年 | 48篇 |
1981年 | 53篇 |
1980年 | 44篇 |
1979年 | 45篇 |
1978年 | 41篇 |
1977年 | 108篇 |
1976年 | 166篇 |
1975年 | 39篇 |
1972年 | 26篇 |
1970年 | 27篇 |
排序方式: 共有5924条查询结果,搜索用时 15 毫秒
901.
902.
Quantifying the economic impact of psychological programs in organizations requires determination of (a) the size and variability of the resulting increase in job performance and (b) the economic value of the increase in job performance. New methods of meta-analysis allow attainment of the 1st of these; and in relation to the 2nd, utility analysis methods provide the ability to translate job performance increases into estimates of the economic value of the program. In the area of personnel selection, many meta-analytic studies have resulted in precise and generalizable estimates of the validity of cognitive ability tests and other selection procedures. Utility analyses show that the job performance increases resulting from use of valid selection methods have substantial economic value. Valid selection produces major increases in work-force productivity. It is concluded that the combined effects of selection and nonselection interventions can be expected to produce substantial increases in workforce productivity. (29 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
903.
Microscopic cysts in the permanent cortices of adrenal glands were studied in a series of 274 infants, some of whom had been stillborn and none of whom were more than 12 months old. After correction for length of gestation, there were no significant relationships between the occurence and number of microcysts and various maternal, placental, and perinatal diseases. A significant direct correlation was demonstrated statistically with shorter gestational period and shorter survival time after birth. We concluded that the adrenal microcysts are either a developmental feature or the result of a greater susceptibility to stress in the fetus and newborn than in older infants. 相似文献
904.
Stanley Pons Bernd Speiser Jerome F. McAleer P.P. Schmidt 《Electrochimica acta》1982,27(12):1711-1714
Orthogonal collocation techniques are used to simulate the solution to the hydrodynamic partial differential equations describing mass transport to a dropping mercury electrode (dme). Accurate values for the concentration profiles and current are obtained with minimal computational effort. 相似文献
905.
A literature review indicates that the standard deviation of employee output averaged 20% of mean output under nonpiecework compensation systems and 15% under piecework systems. For both systems, variability around the mean was small. Implications for selection and workforce productivity are discussed. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
906.
907.
908.
909.
A report is given on the results of radiotherapy in 82 cases of labial carcinoma admitted to the Radiological Clinic, Jena. The absolute 5 years' healing for primary tumours is 73,25%. The absolute 5 year's healing for relapses is 68,9%. The absolute 5 years' healing for regional lymph node metastases is 21,8%. 相似文献
910.
Lorenz-Peter Schmidt Tatsuo Itoh 《Journal of Infrared, Millimeter and Terahertz Waves》1981,2(3):427-436
Generalized fin-lines are analyzed which consist of slots located on more than one interface between dielectric layers inserted in parallel with the E-plane of a waveguide. The analysis is based on a simplified formulation technique based on the spectral domain immittance matrix followed by a Galerkin's method. It allows as many slots as one desires at each interface, and the locations and the widths of these slots are arbitrary. The numerical process to carry out the present analysis is rather efficient. Some numerical data, including propagation constants of the propagating modes as well as characteristic impedances are presented for several structures considered useful for millimeter-wave circuit applications. 相似文献