全文获取类型
收费全文 | 4381篇 |
免费 | 309篇 |
国内免费 | 10篇 |
学科分类
工业技术 | 4700篇 |
出版年
2024年 | 5篇 |
2023年 | 69篇 |
2022年 | 87篇 |
2021年 | 134篇 |
2020年 | 102篇 |
2019年 | 114篇 |
2018年 | 169篇 |
2017年 | 148篇 |
2016年 | 164篇 |
2015年 | 126篇 |
2014年 | 229篇 |
2013年 | 301篇 |
2012年 | 285篇 |
2011年 | 342篇 |
2010年 | 229篇 |
2009年 | 272篇 |
2008年 | 221篇 |
2007年 | 199篇 |
2006年 | 198篇 |
2005年 | 156篇 |
2004年 | 146篇 |
2003年 | 131篇 |
2002年 | 118篇 |
2001年 | 105篇 |
2000年 | 71篇 |
1999年 | 68篇 |
1998年 | 133篇 |
1997年 | 71篇 |
1996年 | 60篇 |
1995年 | 43篇 |
1994年 | 40篇 |
1993年 | 33篇 |
1992年 | 23篇 |
1991年 | 9篇 |
1990年 | 16篇 |
1989年 | 14篇 |
1988年 | 8篇 |
1987年 | 14篇 |
1986年 | 12篇 |
1985年 | 4篇 |
1984年 | 11篇 |
1983年 | 5篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 2篇 |
排序方式: 共有4700条查询结果,搜索用时 0 毫秒
81.
Kwon J Park S Park J Kim B 《Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine》2007,221(4):397-405
Recently, the capsule endoscope has been highlighted for the patient's convenience and the possibility of application in the small intestine. However, the capsule endoscope has some limitations in obtaining an image of the digestive organ because its movement depends only on the peristaltic motion. In order to solve these problems, it is necessary to determine the locomotive mechanism of the capsule endoscope. Therefore, the present authors have already proposed an earthworm-like robot, which has a locomotive mechanism. However, this mechanism should be designed so that the earthworm-like robot has a larger stroke than the critical stroke required to perform motion inside the small intestine. In this study, therefore, not only is the modelling of the locomotive process based on a biomechanical study presented but also the movement of the earthworm-like robot in the small intestine is simulated. Through the simulation process, the variation in the critical stroke with regard to the elastic modulus of the mesentery is investigated. Finally, from an in vitro test of the proposed robot, it is found that the experimental result is very similar to that of the simulation. Consequently, the present work will provide guidelines for designing an earthworm-like robot for diagnosis of the small intestine. 相似文献
82.
A multi-agent intelligent system for efficient ERP maintenance 总被引:9,自引:0,他引:9
The Enterprise Resource Planning (ERP) system is an enterprise-wide integrated software package designed to uphold the highest quality standards of business process. However, for the time being, when the business condition has been changed, the system may not guarantee that the process embedded in ERP is still best. Moreover, since the ERP system is very complex, maintaining the system by trial and error is very costly. Hence, this paper aims to construct a support system that adjusts ERP system to environmental changes. To do so, we adopt multi-agent intelligent technology that enables autonomous cooperation with one another to monitor ERP databases and to find any exceptional changes and then analyze how the changes will affect ERP performance. Moreover, Petri net is applied to manage the complexity and dynamics of agents’ behavior. To show the feasibility of the idea, a prototype agent system, ERP/PN, is proposed and an experiment is conducted. 相似文献
83.
Indicating that CBMC does not satisfy the monotonic property in terms of the number of interactions, Xu and Zhou proposed an augmented definition of CBMC by adopting cut set instead of glue methods. The augmented CBMC clearly satisfies the monotonic property. However, CBMC is designed to overcome the problem with respect to the number of interactions and, therefore, focuses on the interaction pattern, especially, member connectivity. Consequently, it does not make sense to mention the monotonic property of CBMC with respect to interaction number. Moreover, the notion of glue methods allows several interpretations on the design quality of a class. However, that meaningful interpretation is not possible for the augmented definition due to the removal of the notion of glue methods. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
84.
85.
We present a stylized scheme that produces pencil drawings in a range of styles from an image. To produce controllable pencil drawing effects and remedy the problems of existing convolution‐based schemes, we develop a swing bilateral LIC (SBL) filter. Our first approach to express the styled pencil drawings is to control the directions of pencil strokes that depicts both shapes and smooth tone. Another approach is to produce colors of pencil drawings by sampling colors from real color pencils. The third approach is to mimic the artistic technique that increases the details of drawings in a progressive manner. We present drawings in several styles and compare some of them directly with illustrations taken from an artists' work. 相似文献
86.
Haptic and audio cues now appear commonly in computer interfaces, partially due to inherent advantages such as their support for eyes-free interaction. Their invisible, unobservable nature also makes them ideal candidates for security interfaces in which users have to enter secret information such as passwords. In particular, researchers have explored this idea through the design of PIN entry authentication systems based on multi-modal combinations of visual and non-visual content or on the recognition of small sets of unimodal haptic or audio stimuli. This paper highlights the benefits and performance limitations of these approaches and introduces an alternative based on unimodal audio or haptic temporal numerosity – the ability to accurately and rapidly determine the number of cues presented in rapid temporal succession. In essence, in a numerosity interface, rather than recognizing distinct cues, users must count the number of times that a single cue occurs. In an iterative process of design and evaluation, three prototypes implementing this concept are presented and studies of their use reported. The results show the fastest PIN entry times and lowest error rates to be 8 s and 2%, figures that improve substantially on previous research. These results are attained while maintaining low levels of workload and substantial resistance to observation attack (as determined via camera attack security studies). In sum, this paper argues that unimodal audio and haptic numerosity is a valuable and relatively unexplored metaphor for non-visual input and demonstrates the validity of this claim in the demanding task of unobservable authentication systems. 相似文献
87.
Target expansion, i.e., the increase of target size according to cursor movement, can be a practical scheme to improve the usability of target-selection tasks using a mouse. This study examined the effects of different user age groups and target-expansion methods on target-acquisition tasks with grouped icons. Twenty-eight subjects performed acquisition tasks under eight experimental conditions: combinations of four expansion areas (no, one-icon, fish-eye, and group expansion) and two expansion techniques (occlusion and push). Older users took longer to acquire targets than younger users; however, they showed no significant difference in accuracy. Target expansion did not substantially improve performance speed compared to the static condition. However, the error rate was lowest when group area was expanded with the push technique, and both age groups were most satisfied with one-icon area expansion with the occlusion technique. We suggest alternative guidelines in designing target-expansion schemes. 相似文献
88.
89.
Kyungjung Kwon 《Electrochimica acta》2004,49(6):867-872
Cyclic voltammetry (CV) and chronoamperometry have been conducted with the electrochemical quartz crystal microbalance (EQCM) to characterize electron-beam deposited carbon film electrodes in LiClO4-containing mixed electrolytes of ethylene carbonate (EC) and dimethyl carbonate (DMC). For a system whose electrolyte viscosity changes in the course of experiments, such as the above combination of electrode and electrolyte, the mass change per mole of electrons transferred (MPE) of the species on quartz crystals depends on the potential scan rate of CV. Chronoamperometry with a short period is more desirable for the estimation of the MPE of the solid electrolyte interphase (SEI) because the viscosity-induced frequency change, which hinders the correct MPE estimation, constitutes a small portion of the measured frequency change under this experimental condition. 相似文献
90.
The tensile properties and microstructures of various Al alloys fabricated by the pressureless infiltration method under a nitrogen atmosphere were examined. The spontaneous infiltration of molten metal into the powder bed occurred at 800 °C for 1 h under a nitrogen atmosphere. As a result, it was possible to fabricate Al alloys reinforced with AlN particles formed by in situ reaction. A significant strengthening even in the control alloy occurred due to the formation of in situ AlN particle even without an addition of artificial reinforcement. Strength values of the control alloy were increased with decreasing Al powders in bottom powders bed. In addition, tensile strength in Al–Mg alloys was increased with Mg content. 相似文献