全文获取类型
收费全文 | 305796篇 |
免费 | 5860篇 |
国内免费 | 1691篇 |
专业分类
电工技术 | 7259篇 |
技术理论 | 5篇 |
综合类 | 1674篇 |
化学工业 | 55193篇 |
金属工艺 | 11783篇 |
机械仪表 | 8618篇 |
建筑科学 | 9143篇 |
矿业工程 | 2159篇 |
能源动力 | 6450篇 |
轻工业 | 29675篇 |
水利工程 | 3344篇 |
石油天然气 | 6329篇 |
武器工业 | 282篇 |
无线电 | 30211篇 |
一般工业技术 | 55929篇 |
冶金工业 | 52931篇 |
原子能技术 | 5880篇 |
自动化技术 | 26482篇 |
出版年
2021年 | 3901篇 |
2020年 | 3166篇 |
2019年 | 3374篇 |
2018年 | 4317篇 |
2017年 | 4140篇 |
2016年 | 4870篇 |
2015年 | 3969篇 |
2014年 | 5920篇 |
2013年 | 14196篇 |
2012年 | 9043篇 |
2011年 | 11703篇 |
2010年 | 9663篇 |
2009年 | 10410篇 |
2008年 | 10897篇 |
2007年 | 10919篇 |
2006年 | 9589篇 |
2005年 | 8443篇 |
2004年 | 7557篇 |
2003年 | 7083篇 |
2002年 | 6962篇 |
2001年 | 6864篇 |
2000年 | 6347篇 |
1999年 | 6378篇 |
1998年 | 13531篇 |
1997年 | 10105篇 |
1996年 | 7934篇 |
1995年 | 6108篇 |
1994年 | 5664篇 |
1993年 | 5575篇 |
1992年 | 4501篇 |
1991年 | 4135篇 |
1990年 | 4335篇 |
1989年 | 4284篇 |
1988年 | 3963篇 |
1987年 | 3545篇 |
1986年 | 3536篇 |
1985年 | 3962篇 |
1984年 | 3891篇 |
1983年 | 3593篇 |
1982年 | 3175篇 |
1981年 | 3335篇 |
1980年 | 3076篇 |
1979年 | 3299篇 |
1978年 | 3117篇 |
1977年 | 3208篇 |
1976年 | 4034篇 |
1975年 | 2855篇 |
1974年 | 2659篇 |
1973年 | 2881篇 |
1972年 | 2317篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
961.
Assessing the performance of multiprogram workloads running on multithreaded hardware is difficult because it involves a balance between single-program performance and overall system performance. This article argues for developing multiprogram performance metrics in a top-down fashion starting from system-level objectives. The authors propose two performance metrics: average normalized turnaround time, a user-oriented metric, and system throughput, a system-oriented metric. 相似文献
962.
It is well recognized that the impact-acoustic emissions contain information that can indicate the presence of the adhesive defects in the bonding structures. In our previous papers, artificial neural network (ANN) was adopted to assess the bonding integrity of the tile–walls with the feature extracted from the power spectral density (PSD) of the impact-acoustic signals acting as the input of classifier. However, in addition to the inconvenience posed by the general drawbacks such as long training time and large number of training samples needed, the performance of the classic ANN classifier is deteriorated by the similar spectral characteristics between different bonding status caused by abnormal impacts. In this paper our previous works was developed by the employment of the least-squares support vector machine (LS-SVM) classifier instead of the ANN to derive a bonding integrity recognition approach with better reliability and enhanced immunity to surface roughness. With the help of the specially designed artificial sample slabs, experiments results obtained with the proposed method are provided and compared with that using the ANN classifier, demonstrating the effectiveness of the present strategy. 相似文献
963.
The reasons of the absence of interoperability of the National system of electronic digital signatures (EDS) are analyzed
based on systems analysis. An attempt is made to substantiate the minimax (minimum costs and maximum results) way of solving
interoperability problems in EDS infrastructure in both Ukraine and foreign states. 相似文献
964.
Mats L. Cain J.T. Mickle M.H. 《Automation Science and Engineering, IEEE Transactions on》2009,6(1):4-8
In this paper, an indirect noninvasive method for measuring input impedance and the variations in the assembly of the interconnect and packaging between antenna and the integrated circuit (IC) effects of passive radio frequency identification (RFID) transponder (tags) antennas is presented. The analysis of different RFID tags is presented together with the experimental data. 相似文献
965.
Teleoperation is essential for applications in which, despite the availability of a precise geometrical definition of the working area, a task cannot be explicitly programmed. This paper describes a method of assisted teleoperation that improves the execution of such tasks in terms of ergonomics, precision, and reduction of execution time. The relationships between the operating spaces corresponding to the human-robot interface triangle are analyzed. The proposed teleoperation aid is based on applying adaptive transformations between these spaces. 相似文献
966.
967.
968.
I. V. Bushlanov A. M. Gortsev L. A. Nezhel’skaya 《Automation and Remote Control》2008,69(9):1517-1533
Consideration was given to estimation of the parameters of the synchronous twofold-stochastic flow of events which makes up a mathematical model of the information flow of demands circulating in the queuing systems and networks. Two variants were studied. For the first variant, the problem of optimal estimation of the parameters of a synchronous flow of events with a finite arbitrary number of states was solved. The second variant differs in that the event flow operates in the environment where part of events is lost during the so-called dead time. Consideration was given to a synchronous flow with two states. The problem of estimating the length of the dead time in the conditions of continued dead time was solved. The results of numerical estimation based on the simulation model of the synchronous flow were presented for both variants. 相似文献
969.
I. M. Kozlov S. L. Min'ko G. S. Romanov D. É. Skoromnik 《Journal of Engineering Physics and Thermophysics》1994,66(2):137-140
The problem of the cooling of a spherical volume of air after departure of a shock wave in air of normal density is studied numerically. Based on the results obtained, a conclusion is made that no radiative cooling wave exists in a real atmosphere.Academic Scientific Complex A. V. Luikov Heat and Mass Transfer Institute of the Academy of Sciences of Belarus, Minsk, Belarus. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 66, No. 2, pp. 155–158, February, 1994 相似文献
970.
L. É. Rikenglaz 《Journal of Engineering Physics and Thermophysics》1994,66(2):212-214
A method is suggested for constructing the terms in an asymptotic series in a small parameter when seeking the position of the phase front y() in the Stefan boundary-value problem of the first kind for a semi-infinite medium that is at the phase transition temperature at the initial moment.St. Petersburg Mining Institute. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 66, No. 2, pp. 235–237, February, 1994. 相似文献