全文获取类型
收费全文 | 1582篇 |
免费 | 34篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 36篇 |
综合类 | 2篇 |
化学工业 | 453篇 |
金属工艺 | 33篇 |
机械仪表 | 15篇 |
建筑科学 | 88篇 |
矿业工程 | 8篇 |
能源动力 | 28篇 |
轻工业 | 254篇 |
水利工程 | 10篇 |
石油天然气 | 1篇 |
无线电 | 69篇 |
一般工业技术 | 223篇 |
冶金工业 | 242篇 |
原子能技术 | 7篇 |
自动化技术 | 149篇 |
出版年
2022年 | 23篇 |
2021年 | 32篇 |
2020年 | 22篇 |
2019年 | 28篇 |
2018年 | 21篇 |
2017年 | 14篇 |
2016年 | 30篇 |
2015年 | 29篇 |
2014年 | 35篇 |
2013年 | 52篇 |
2012年 | 49篇 |
2011年 | 65篇 |
2010年 | 57篇 |
2009年 | 44篇 |
2008年 | 47篇 |
2007年 | 57篇 |
2006年 | 45篇 |
2005年 | 35篇 |
2004年 | 38篇 |
2003年 | 35篇 |
2002年 | 33篇 |
2001年 | 14篇 |
2000年 | 28篇 |
1998年 | 33篇 |
1997年 | 36篇 |
1996年 | 26篇 |
1995年 | 23篇 |
1994年 | 29篇 |
1993年 | 26篇 |
1992年 | 39篇 |
1991年 | 19篇 |
1990年 | 31篇 |
1989年 | 21篇 |
1988年 | 14篇 |
1987年 | 24篇 |
1986年 | 14篇 |
1985年 | 29篇 |
1984年 | 24篇 |
1983年 | 24篇 |
1982年 | 16篇 |
1981年 | 25篇 |
1980年 | 14篇 |
1979年 | 13篇 |
1978年 | 24篇 |
1977年 | 16篇 |
1976年 | 18篇 |
1974年 | 13篇 |
1972年 | 15篇 |
1970年 | 14篇 |
1963年 | 13篇 |
排序方式: 共有1618条查询结果,搜索用时 15 毫秒
131.
Holahan Charles J.; Moos Rudolf H.; Holahan Carole K.; Cronkite Ruth C.; Randall Patrick K. 《Canadian Metallurgical Quarterly》2003,112(1):159
This study examined drinking to cope with distress and drinking behavior in a baseline sample of 412 unipolar depressed patients assessed 4 times over a 10-year period. Baseline drinking to cope operated prospectively as a risk factor for more alcohol consumption at 1-, 4, and 10-year follow-ups and for more drinking problems at 1- and 4-year follow-ups. Findings elucidate a key mechanism in this process by showing that drinking to cope strengthened the link between depressive symptoms and drinking behavior. Individuals who had a stronger propensity to drink to cope at baseline showed a stronger connection between depressive symptoms and both alcohol consumption and drinking problems. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
132.
This observational study compared a nationwide sample of older patients with substance use disorders (n = 3,598; age > 55) with a demographically and diagnostically matched sample of younger patients on initial functioning, subsequent outpatient mental health service use, and 12-month follow-up outcomes. Older patients were initially functioning as well as or better than younger patients according to substance use, psychiatric, family, and legal criteria. The groups received comparable amounts of outpatient mental health care. At a 12-month follow-up, older patients generally had better substance use and functioning outcomes than did younger patients. The findings suggest that older patients with substance use disorders are keeping pace with demographically and diagnostically comparable younger patients in obtaining specialized outpatient mental health services and that they have positive treatment prognoses. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
133.
134.
135.
In this paper we determine the probability distribution function of cumulated instantaneous interference power in a mobile
radio network, when the positions of interfering stations are distributed according to a one‐ or two‐dimensional Poisson point
process, truncated at a finite horizon. The influences of Rice and Rayleigh fading, lognormal shadowing, near far effect and
capture are taken into account. From the resulting distribution the probability of successful transmission and corresponding
bit‐error‐rates are derived.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
136.
137.
This paper deals with the distribution of cumulated instantaneous interference power in a Rayleigh fading channel for an infinite number of interfering stations, where each station transmits with a certain probability, independently of all others. If all distances are known, a necessary and sufficient condition is given for the corresponding distribution to be nondefective. Explicit formulae of density and distribution functions are obtained in the interesting special case that interfering stations are located on a linear grid. Moreover, the Laplace transform of cumulated power is investigated when the positions of stations follow a one- or two-dimensional Poisson process. It turns out that the corresponding distribution is defective for the two-dimensional models.This work was supported by the Deutsche Forschungsgemeinschaft under grant no. Ma 1184/2-3. 相似文献
138.
139.
Stecher M. Jensen N. Denison M. Rudolf R. Strzalkoswi B. Muenzer M.N. Lorenz L. 《Power Electronics, IEEE Transactions on》2005,20(3):537-549
System integration and high power density of monolithic and multichip designs are the driving force for the progress in power electronic systems. The whole system has to be considered and optimized to meet this target and to keep the overall ruggedness, sensitivity toward electromagnetic interference and long term reliability, Silicon utilization system reliability and power units miniaturization are the key factors. In this paper new technologies, advanced devices concepts and future system aspect for system-integration in the automotive and industrial segments are discussed. In both fields of applications these are huge requirements toward system dynamic characteristic, overload capability, ruggedness behavior and reliability. In the automotive segment technologies working at high operating temperatures are required and in the industrial are high blocking voltage capabilities are needed. 相似文献
140.
Finite element simulation of package stress in transfer molded MEMS pressure sensors 总被引:2,自引:0,他引:2
Rudolf Krondorfer Yeong K. Kim Jaeok Kim Claes-Gran Gustafson Timothy C. Lommasson 《Microelectronics Reliability》2004,44(12):1995-2002
The goal of this paper is to investigate the effect of residual packaging stress resulting from transfer molding of a micro electro mechanical system pressure sensor. A model of a silicon diaphragm micro electro mechanical system pressure sensor geometry was used to simulate the stresses developed during the molding process. The analyses were carried out with an assumption that the epoxy molding compound was a temperature dependent elastic material. Finite element analysis was used to calculate the residual packaging stress. The stress values were used to obtain the electrical output signal and sensitivity of the packaged sensor. In this way, a direct link was established between package stress and device performance.The calculated output signal and sensitivity were compared with experimental data to verify the simulated stress and hence determine the effect of the packaging process on the pressure sensor. Four different service temperatures were considered to examine the temperature effects on the output signal and the sensitivity for the packaged sensor. 相似文献