全文获取类型
收费全文 | 18462篇 |
免费 | 289篇 |
国内免费 | 17篇 |
专业分类
电工技术 | 241篇 |
综合类 | 9篇 |
化学工业 | 3604篇 |
金属工艺 | 280篇 |
机械仪表 | 310篇 |
建筑科学 | 1108篇 |
矿业工程 | 109篇 |
能源动力 | 515篇 |
轻工业 | 1392篇 |
水利工程 | 177篇 |
石油天然气 | 225篇 |
武器工业 | 1篇 |
无线电 | 1101篇 |
一般工业技术 | 2907篇 |
冶金工业 | 4177篇 |
原子能技术 | 163篇 |
自动化技术 | 2449篇 |
出版年
2022年 | 145篇 |
2021年 | 238篇 |
2020年 | 211篇 |
2019年 | 255篇 |
2018年 | 272篇 |
2017年 | 260篇 |
2016年 | 327篇 |
2015年 | 239篇 |
2014年 | 380篇 |
2013年 | 1101篇 |
2012年 | 664篇 |
2011年 | 871篇 |
2010年 | 674篇 |
2009年 | 663篇 |
2008年 | 859篇 |
2007年 | 871篇 |
2006年 | 685篇 |
2005年 | 719篇 |
2004年 | 559篇 |
2003年 | 570篇 |
2002年 | 509篇 |
2001年 | 329篇 |
2000年 | 301篇 |
1999年 | 303篇 |
1998年 | 316篇 |
1997年 | 301篇 |
1996年 | 301篇 |
1995年 | 333篇 |
1994年 | 267篇 |
1993年 | 304篇 |
1992年 | 272篇 |
1991年 | 164篇 |
1990年 | 237篇 |
1989年 | 283篇 |
1988年 | 204篇 |
1987年 | 215篇 |
1986年 | 211篇 |
1985年 | 265篇 |
1984年 | 258篇 |
1983年 | 227篇 |
1982年 | 217篇 |
1981年 | 213篇 |
1980年 | 175篇 |
1979年 | 187篇 |
1978年 | 176篇 |
1977年 | 177篇 |
1976年 | 148篇 |
1975年 | 178篇 |
1974年 | 165篇 |
1973年 | 133篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
62.
Richard Baskerville 《欧洲信息系统杂志》2011,20(3):251-254
63.
64.
Some students (base group) played the Circuit Game, a 10-level computer-based learning activity intended to help students learn how electrical circuits work. Other students (competition group) played the same game but with competition features added - including a score bar showing performance on each level, the opportunity to earn one ticket per level if a performance criterion is met, and the opportunity to win a prize based on the number of tickets earned. On a retention test given after the game, the competition group remembered significantly more than the base group (d = 0.47). On an embedded transfer test constituting the final level of the game, the groups did not differ significantly. However, on the transfer test there was a significant gender by group interaction in which men performed worse in the competition group than the base group (d = −0.54) and women performed better in the competition group than the base group (d = 0.24). Overall, adding game-like features to a computer-based learning activity caused students to pay attention to game details but did not motivate students - particularly men - to learn more deeply. 相似文献
65.
Semiconductor wafer fabrication system (SWFS) is the most complex and capital-intensive phase in the entire semiconductor manufacturing cycle. With characteristics of re-entrant processing routes, equipment uncertainty, product diversity and improving technologies, great challenges are presented in SWFS’s modeling, scheduling and simulation. To implement efficient production control, this paper provides a timed extended object-oriented Petri nets (TEOPNs) approach to performance modeling, real-timed dispatching and simulation of SWFSs. The TEOPNs models are constructed in a hierarchy to accord with the real-world SWFS’s organization, and a new type of signal place is added into the TEOPNs to respond the dynamic states of all processing facilities. A novel autonomy and coordination-based real-time dispatching mechanism (A&C-RDM) is developed in this paper, which executes under the support of the TEOPNs-based hybrid real-time dispatching control system (HRDCS). Owning to the ability of gathering dynamic real-time information of all production facilities and WIP products, the HRDCS can make adaptive dispatching decisions according to the local and global real-time processing status. Two sets of key elements of real-time dispatching, i.e. the state thresholds and dispatching rules, are defined in the HRDCS so that the A&C-RDM can integrate different types of dispatching rules. A set of simulation experiments prove the efficiency of the proposed modeling and dispatching algorithm. In summary, the proposed TEOPNs, HRDCS and A&C-RDM form the cornerstones of a real-time dispatching simulation prototype of SWFS, and the work described in this paper carries out an advanced integrated “modeling–dispatching–simulation” methodology. 相似文献
66.
This paper introduces the concept of the temporal think tank™ (T3™), a temporary in-house research center, based on case studies with a highly automated global manufacturer and in various small-sized manufacture (SME's). The T3™ brings individuals from across the organization together in a team setting in which they are charged to look at the future, develop their decision-making skills, and use entrepreneurial thinking to incubate new processes and/or products. After an appropriate time in the temporal think tank™, the individuals are asked to return to their regular positions to implement the best practices and best ideas and doing so spur the organization forward. At intervals, the temporal think tanks™ can be reconvened, or reconstituted with new participants. This approach prepares technology champions for the SME, who can return to the organization with a fresh outlook and renewed energy to keep the enterprise at the peak of efficiency and effectiveness. 相似文献
67.
68.
69.
This paper investigates packet scheduling in the context of Self-Optimizing Networks, and demonstrates how to improve coverage dynamically by adjusting the scheduling strategy. We focus on α-fair schedulers, and we provide methods for calculating the scheduling gain, including several closed form formulas. Scheduling gain is analyzed for different fading models, with a particular focus on the frequency-selective channel. We then propose a coverage-capacity self-optimization algorithm based on α-fair schedulers. A use case illustrates the implementation of the algorithm and simulation results show that important coverage gains are achieved at the expense of very little computing power. 相似文献
70.
An experimental technique is presented to measure reflectance at high sample temperature with respect to room temperature in the infrared using Fourier transform infrared fitted with a reflectometer. Sample temperature artifacts are accounted for by sequential measurements taken with the lamp source on and with the lamp source off. The sequential measurements are shown mathematically to correct for the modulation of sample and detector thermal emissions. Further, the technique is applied to a polyimide (PMDA-ODA) film on a layer of gold deposited on a thermally oxidized Si wafer. It is shown that the optical properties (index of refraction and extinction coefficient) remain relatively constant with temperature (from room temperature to 380 degrees C) in the 4000-6000 cm(-1) spectral region. The significant changes that occur with temperature are the change in thickness of the film and also the spectral properties in the 2000-4000 cm(-1) region. Also, by using a Lorentz oscillator model, it is shown that this method is able to discern that spectral features corresponding to the OH stretching bands at 3630 and 3470 cm(-1) show significant variation with increasing temperature. 相似文献