全文获取类型
收费全文 | 2509篇 |
免费 | 3篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 19篇 |
化学工业 | 186篇 |
金属工艺 | 10篇 |
机械仪表 | 20篇 |
建筑科学 | 39篇 |
矿业工程 | 1篇 |
能源动力 | 13篇 |
轻工业 | 116篇 |
水利工程 | 8篇 |
石油天然气 | 4篇 |
无线电 | 124篇 |
一般工业技术 | 129篇 |
冶金工业 | 1694篇 |
原子能技术 | 14篇 |
自动化技术 | 136篇 |
出版年
2021年 | 8篇 |
2019年 | 15篇 |
2018年 | 7篇 |
2017年 | 8篇 |
2016年 | 8篇 |
2015年 | 8篇 |
2014年 | 21篇 |
2013年 | 62篇 |
2012年 | 33篇 |
2011年 | 44篇 |
2010年 | 28篇 |
2009年 | 27篇 |
2008年 | 42篇 |
2007年 | 34篇 |
2006年 | 24篇 |
2005年 | 35篇 |
2004年 | 28篇 |
2003年 | 39篇 |
2002年 | 25篇 |
2001年 | 16篇 |
2000年 | 13篇 |
1999年 | 75篇 |
1998年 | 461篇 |
1997年 | 272篇 |
1996年 | 196篇 |
1995年 | 144篇 |
1994年 | 93篇 |
1993年 | 108篇 |
1992年 | 34篇 |
1991年 | 40篇 |
1990年 | 38篇 |
1989年 | 53篇 |
1988年 | 39篇 |
1987年 | 46篇 |
1986年 | 40篇 |
1985年 | 39篇 |
1984年 | 9篇 |
1983年 | 15篇 |
1982年 | 14篇 |
1981年 | 14篇 |
1980年 | 28篇 |
1979年 | 9篇 |
1978年 | 14篇 |
1977年 | 43篇 |
1976年 | 70篇 |
1975年 | 9篇 |
1971年 | 7篇 |
1968年 | 6篇 |
1967年 | 6篇 |
1966年 | 7篇 |
排序方式: 共有2513条查询结果,搜索用时 15 毫秒
61.
The increasing popularity of online and multiplayer games has meant that for many, social interaction and cooperation are vital components of the gaming experience. Previous research has suggested that not only has this made gaming more attractive to socially oriented people but also that it may be socially beneficial in terms of social capital and prosocial behaviors. However, for problematic video game players (those showing signs of compulsive or detrimental video game use), this may not be the case, and a number of theories hold deficiencies in socializing in real life as central to the development of this issue. In the present study, an online questionnaire completed by 416 participants assessed problematic video game use, extraversion, trait empathy, online and offline social capital and prosocial tendencies. Contrary to hypotheses, non-problematic, problematic and non-gamers did not differ in empathy, extraversion or prosocial tendencies. Problematic video game play was, however, associated with significantly higher online social capital and lower offline social capital whereas non-problematic players demonstrated only higher online capital than non-players. This highlights the importance of social support but suggests personality is not an influential factor. 相似文献
62.
In this article, I describe the design of an early 1950s attempt to build a relatively low-cost computer, using a mechanical desktop calculator to perform the arithmetic operations. The resulting computer-one of the earliest attempts at building a "minicomputer"-could perform stored-program addition, subtraction, multiplication, and division, as well as carry out a simple decision operation based on a number comparison. To solve a problem, the operator would type in a program sequence based on the use of nine basic instructions. Total memory capacity was 400 words. 相似文献
63.
Computer vision for interactive computer graphics 总被引:3,自引:0,他引:3
Freeman W.T. Anderson D.B. Beardsley P. Dodge C.N. Roth M. Weissman C.D. Yerazunis W.S. Kage H. Kyuma I. Miyake Y. Tanaka K. 《Computer Graphics and Applications, IEEE》1998,18(3):42-53
Vision can be a powerful interface device for computers because of its potential for sensing body position, head orientation, direction of gaze, pointing commands, and gestures. Such unencumbered interaction can make computers easier to use. We describe vision algorithms for interactive graphics and present vision-controlled graphics applications using these algorithms. Some applications employ an artificial retina chip for image detection or preprocessing 相似文献
64.
A. Rosenqvist M. Shimada B. Chapman A. Freeman G. De Grandi S. Saatchi 《International journal of remote sensing》2013,34(6-7):1375-1387
The Global Rain Forest Mapping (GRFM) project is an international endeavour led by the National Space Development Agency of Japan (NASDA), with the aim of producing spatially and temporally contiguous Synthetic Aperture Radar (SAR) data sets over the tropical belt on the Earth by use of the JERS-1 L-band SAR, through the generation of semi-continental, 100 m resolution, image mosaics. The GRFM project relies on extensive collaboration with the National Aeronautics and Space Administration (NASA), the Joint Research Centre of the European Commission (JRC) and the Japanese Ministry of International Trade and Industry (MITI) for data acquisition, processing, validation and product generation. A science programme is underway in parallel with product generation. This involves the agencies mentioned above, as well as a large number of international organizations, universities and individuals to perform field activities and data analysis at different levels. The GRFM project was initiated in 1995 and, through a dedicated data acquisition policy by NASDA, data acquisitions could be completed within a 1.5-year period, resulting in a spatially and temporally homogeneous coverage to encompass the entire Amazon Basin from the Atlantic to the Pacific; Central America up to the Yucatan Peninsular in Mexico; equatorial Africa from Madagascar and Kenya in the east to Sierra Leone in the west; and south-east Asia, including Papua New Guinea and northern Australia. Over the Amazon and Congo river basins, the project aimed to provide complete cover at two different seasons, featuring the basins at high and low water. In total, the GRFM acquisitions comprise some 13000 SAR scenes, which are currently in the course of being processed and compiled into image mosaics. In March 1999, SAR mosaics over the Amazon Basin (one out of two seasonal coverages) and equatorial Africa (both seasonal coverages) were completed; the data are available on CD-ROM and, at a coarser resolution, via the Internet. Coverage of the second-season Amazon and Central America will be completed during 1999, with the south-east Asian data sets following thereafter. All data are being provided free of charge to the international science community for research and educational purposes. 相似文献
65.
In this article, a null space damping method is proposed that solves the stability problem commonly encountered in existing local joint torque optimization techniques applied to redundant manipulators. The damped joint motion is stable and globally outperforms undamped techniques in the sense of torque minimization capability. In addition, simulation results show that the resulting damped joint motion becomes conservative after an initial transient stage for cyclic end-effector trajectories, while undamped pseudoinverse solutions are reported to never lead to conservative motion. Three undamped and damped joint torque optimization algorithms are considered and discussed with comparison to the previous literature. The effectiveness of the proposed null space damping method is demonstrated by the results of two computer simulations. In addition, the minimization of electrical power consumption is addressed with respect to the results of this article. 相似文献
66.
K.M. Wilcken S.P.H.T. Freeman A. Dougans S. Xu R. Loger C. Schnabel 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2010,268(7-8):748-751
Small changes to our ion source and gas ionization detector have significantly improved Cl measurement by reducing source memory and increasing interference rejection. Gas stripped low energy 30 MeV 36Cl5+ ions are still efficiently transported to the detector but 36S vs. 36Cl separation is improved by an order of magnitude. Accordingly 36Cl/Cl background is <10?15 before additional interference correction that is also newly automated. 35Cl? currents have increased to 30 μA and 36Cl/Cl inter-cathode repeatability is 3%. 相似文献
67.
K.M. Wilcken S.P.H.T. Freeman A. Dougans S. Xu A. Galbiati K. Oliver 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2010,268(7-8):851-853
14C ions (290 keV) have been detected with chemically vapour deposited diamond. Potential benefits of diamond detectors are radiation hardness, high charge collection and very fast response time/high bandwidth. 相似文献
68.
Virtual instruments for an extracorporeal circulation (ECC) process were developed to simulate the reactions of a patient to different artificial perfusion conditions. The computer simulation of the patient takes into account the hydraulic, volume, thermal and biochemical phenomena and their interaction with the devices involved in ECC (cannulae dimensions, oxygenator and filter types, pulsatile or continuous pump and thermal exchangers). On the basis of the patient's initialisation data (height, weight, Ht) and perfusion variables (pump flow rate, water temperature, gas flow rate and composition) imposed by the operator, the virtual ECC monitors simulated arterial and venous pressure tracings in real time, along with arterial and venous flow rate tracings, urine production tracing and temperature levels. Oxyhemoglobin arterial and venous blood saturation together with other related variables (pO2, pCO2, pH, HCO3 are also monitored. A drug model which allows the simulation of the effect of vasodilator and diuretic drugs is also implemented. Alarms are provided in order to check which variables (pressure, saturation, pH, urine flow) are out of the expected ranges during the ECC simulation. Consequently the possibility of modifying the control parameters of the virtual devices of the ECC in run-time mode offers an interaction mode between the operator and the virtual environment. 相似文献
69.
70.