全文获取类型
收费全文 | 12896篇 |
免费 | 1409篇 |
国内免费 | 1017篇 |
专业分类
电工技术 | 507篇 |
技术理论 | 1篇 |
综合类 | 1078篇 |
化学工业 | 1861篇 |
金属工艺 | 384篇 |
机械仪表 | 556篇 |
建筑科学 | 1571篇 |
矿业工程 | 140篇 |
能源动力 | 463篇 |
轻工业 | 762篇 |
水利工程 | 375篇 |
石油天然气 | 236篇 |
武器工业 | 108篇 |
无线电 | 923篇 |
一般工业技术 | 2173篇 |
冶金工业 | 656篇 |
原子能技术 | 247篇 |
自动化技术 | 3281篇 |
出版年
2024年 | 68篇 |
2023年 | 352篇 |
2022年 | 512篇 |
2021年 | 666篇 |
2020年 | 556篇 |
2019年 | 496篇 |
2018年 | 461篇 |
2017年 | 524篇 |
2016年 | 539篇 |
2015年 | 495篇 |
2014年 | 774篇 |
2013年 | 908篇 |
2012年 | 798篇 |
2011年 | 872篇 |
2010年 | 628篇 |
2009年 | 686篇 |
2008年 | 694篇 |
2007年 | 736篇 |
2006年 | 606篇 |
2005年 | 563篇 |
2004年 | 474篇 |
2003年 | 419篇 |
2002年 | 380篇 |
2001年 | 318篇 |
2000年 | 257篇 |
1999年 | 238篇 |
1998年 | 185篇 |
1997年 | 164篇 |
1996年 | 128篇 |
1995年 | 138篇 |
1994年 | 93篇 |
1993年 | 78篇 |
1992年 | 72篇 |
1991年 | 63篇 |
1990年 | 66篇 |
1989年 | 64篇 |
1988年 | 56篇 |
1987年 | 24篇 |
1986年 | 13篇 |
1985年 | 22篇 |
1984年 | 16篇 |
1983年 | 23篇 |
1982年 | 14篇 |
1980年 | 9篇 |
1979年 | 8篇 |
1966年 | 6篇 |
1964年 | 6篇 |
1959年 | 7篇 |
1958年 | 5篇 |
1955年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 625 毫秒
21.
The effects of physical embodiment and physical presence were explored through a survey of 33 experimental works comparing how people interacted with physical robots and virtual agents. A qualitative assessment of the direction of quantitative effects demonstrated that robots were more persuasive and perceived more positively when physically present in a user׳s environment than when digitally-displayed on a screen either as a video feed of the same robot or as a virtual character analog; robots also led to better user performance when they were collocated as opposed to shown via video on a screen. However, participants did not respond differently to physical robots and virtual agents when both were displayed digitally on a screen – suggesting that physical presence, rather than physical embodiment, characterizes people׳s responses to social robots. Implications for understanding psychological response to physical and virtual agents and for methodological design are discussed. 相似文献
22.
Supported metal catalysts, particularly noble metals supported on SiO2, have attracted considerable attention due to the importance of the silica–metal interface in heterogeneous catalysis and in electronic device fabrication. Several important issues, e.g., the stability of the metal–oxide interface at working temperatures and pressures, are not well-understood. In this review, the present status of our understanding of the metal–silica interface is reviewed. Recent results of model studies in our laboratories on Pd/SiO2/Mo(1 1 2) using LEED, AES and STM are reported. In this work, epitaxial, ultrathin, well-ordered SiO2 films were grown on a Mo(1 1 2) substrate to circumvent complications that frequently arise from the silica–silicon interface present in silica thin films grown on silicon. 相似文献
23.
Study of elastic wave propagation induced by piezoelectric actuators for crack identification 总被引:1,自引:0,他引:1
The current paper provides a theoretical study of elastic wave propagation in a cracked elastic medium induced by an embedded piezoelectric actuator. The formulation of the problem is based on a newly developed actuator model and the solution of coupled crack and actuator problems. The interaction between an actuator and a crack is studied to develop basic understanding of the effect of the crack upon the wave field generated. The resulting wave field is used to simulate 'sensor signals'. Scattered wave from the crack is then regenerated by solving a reverse elastodynamic problem and used in an imaging technique to identify the crack. 相似文献
24.
Yuqin LiHatsuo Ishida 《Polymer》2003,44(21):6571-6577
Polystyrene nanocomposites have been prepared via solution intercalation method. Combination of wide-angle X-ray diffraction and thermogravimetric analysis is used to study the effect of solvents on the morphology of the nanocomposites as a function of the amount of residual solvent. d-Spacing of the polystyrene nanocomposites has a minimum value when the residual solvent concentration is between 2 and 4 wt%. Different interaction level between the solvent molecules and polymer chains is considered to be the reason for this special d-spacing change behavior. By comparing the solution intercalation of polystyrene and poly(ethyl methacrylate) from different solvents, it is concluded that the interactions between polymer-surfactant, solvent-surfactant, and polymer-solvent play important role for the solution intercalation of polymers. 相似文献
25.
We present calculations of the magnetoconductivity in a two-dimensional electron system including the Rashba spin-orbit interaction. Essential for these calculations is an extension of the self-consistent Born approximation which takes into account the electron spin degree of freedom. The calculated magnetoconductivity exhibits, besides the beating in the Shubnikov-de Haas oscillations, a modulation related to the spin-orbit induced crossings of Landau levels, as a consequence of spin-conserving scattering between spin-orbit coupled states. 相似文献
26.
本文报道用提拉法测量Hg_(1-x)Mn_xTe单晶磁化强度的实验结果.在低温1.5K-30K范图内,磁场强度为0-7万高斯下,测量了不同组分x=0.06,0.08,0.12,0.16的Hg_(1-x)Mn_xTe磁化强度与组分,温度和磁场强度的关系.采用分子场近似模型,用类布里渊函数,最小二乘法对实验结果进行了拟合和分析.结果表明在本文x值范围内,理论与实验符合较好,证实了锰离子间存在强的反铁磁交换耦合. 相似文献
27.
S. ReppA. Sadiki C. SchneiderA. Hinz T. LandenfeldJ. Janicka 《International Journal of Heat and Mass Transfer》2002,45(6):1271-1285
This work aims to compare numerical results obtained by using the Monte Carlo composition-PDF method and a presumed-β-PDF in order to reveal their effects on the prediction of flow and scalar fields in swirling confined methane diffusion flame. Using the intrinsic low dimensional manifolds method for modelling the chemistry and a second moment closure for the turbulence, it is shown that both PDF-methods provide a similar accuracy level of the prediction of mean quantities. While the presumed-β-PDF performs using reasonable computational efforts, the Monte Carlo-PDF allows to capture well the turbulence-chemistry interaction and strong finite-chemistry effects such as local extinction. 相似文献
28.
29.
Chris Harty 《Building Research & Information》2005,33(6):512-522
An alternative approach to understanding innovation is made using two intersecting ideas. The first is that successful innovation requires consideration of the social and organizational contexts in which it is located. The complex context of construction work is characterized by inter-organizational collaboration, a project-based approach and power distributed amongst collaborating organizations. The second is that innovations can be divided into two modes: 'bounded', where the implications of innovation are restricted within a single, coherent sphere of influence, and 'unbounded', where the effects of implementation spill over beyond this. Bounded innovations are adequately explained within the construction literature. However, less discussed are unbounded innovations, where many firms' collaboration is required for successful implementation, even though many innovations can be considered unbounded within construction's inter-organizational context. It is argued that unbounded innovations require an approach to understand and facilitate the interactions both within a range of actors and between the actors and technological artefacts. The insights from a sociology of technology approach can be applied to the multiplicity of negotiations and alignments that constitute the implementation of unbounded innovation. The utility of concepts from the sociology of technology, including 'system building' and 'heterogeneous engineering', is demonstrated by applying them to an empirical study of an unbounded innovation on a major construction project (the new terminal at Heathrow Airport, London, UK). This study suggests that 'system building' contains outcomes that are not only transformations of practices, processes and systems, but also the potential transformation of technologies themselves. 相似文献
30.
GAO Qinglu~ WU Bo~ GUO Guang~ .School of Management Wuhan University of Technology Wuhan China .School of Mechanical Engineering Huazhong University of Science Technology Wuhan China 《武汉理工大学学报》2006,28(Z2)
This article puts forward a scheduling method for nonlinear process plan shop floor.Task allocation and load bal- ance are realized by bidding mechanism.Though the agent interaction process,the execution of tasks is determined and the coherence of manufacturing decision is verified.The employment of heuristic index can help to optimize the system performance. 相似文献