全文获取类型
收费全文 | 61593篇 |
免费 | 3507篇 |
国内免费 | 192篇 |
学科分类
工业技术 | 65292篇 |
出版年
2023年 | 612篇 |
2022年 | 392篇 |
2021年 | 1601篇 |
2020年 | 1269篇 |
2019年 | 1389篇 |
2018年 | 1733篇 |
2017年 | 1699篇 |
2016年 | 2103篇 |
2015年 | 1599篇 |
2014年 | 2550篇 |
2013年 | 3895篇 |
2012年 | 3893篇 |
2011年 | 4738篇 |
2010年 | 3457篇 |
2009年 | 3592篇 |
2008年 | 3487篇 |
2007年 | 2757篇 |
2006年 | 2514篇 |
2005年 | 2155篇 |
2004年 | 1991篇 |
2003年 | 1884篇 |
2002年 | 1631篇 |
2001年 | 1363篇 |
2000年 | 1142篇 |
1999年 | 1108篇 |
1998年 | 2177篇 |
1997年 | 1425篇 |
1996年 | 1078篇 |
1995年 | 808篇 |
1994年 | 712篇 |
1993年 | 626篇 |
1992年 | 432篇 |
1991年 | 406篇 |
1990年 | 393篇 |
1989年 | 372篇 |
1988年 | 291篇 |
1987年 | 255篇 |
1986年 | 214篇 |
1985年 | 210篇 |
1984年 | 174篇 |
1983年 | 130篇 |
1982年 | 88篇 |
1981年 | 100篇 |
1980年 | 90篇 |
1979年 | 79篇 |
1978年 | 73篇 |
1977年 | 105篇 |
1976年 | 160篇 |
1975年 | 67篇 |
1973年 | 54篇 |
排序方式: 共有10000条查询结果,搜索用时 258 毫秒
51.
Hun Soo Jang Seonggwang Yoo Seong Hyeon Kang Jongjun Park Gi‐Gwan Kim Heung Cho Ko 《Advanced functional materials》2020,30(5)
This work demonstrates a means of automatic transformation from planar electronic devices to desirable 3D forms. The method uses a spatially designed thermoplastic framework created via extrusion shear printing of acrylonitrile–butadiene–styrene (ABS) on a stress‐free ABS film, which can be laminated to a membrane‐type electronic device layer. Thermal annealing above the glass transition temperature allows stress relaxation in the printed polymer chains, resulting in an overall shape transformation of the framework. In addition, the significant reduction in the Young's modulus and the ability of the polymer chains to reflow in the rubbery state release the stress concentration in the electronic device layer, which can be positioned outside the neutral mechanical plane. Electrical analyses and mechanical simulations of a membrane‐type Au electrode and indium gallium zinc oxide transistor arrays before and after transformation confirm the versatility of this method for developing 3D electronic devices based on planar forms. 相似文献
52.
Multimedia Systems - The preferences of Web information purchasers are changing. Cost-effectiveness (i.e., an emphasis on performance with respect to price) is becoming less regarded than... 相似文献
53.
Jaekyung Kim Youngshin Kim Euy Sik Jeon 《Journal of Mechanical Science and Technology》2018,32(12):5653-5657
Maintaining a vacuum between the two glasses to maximize the heat insulating performance, it is indispensable to array the pillar for the vacuum glazing to maintain the vacuum gap. In this paper, to investigate the effect of the spacing of the pillars arranged using the screen printing method on the strength of the glass, a bending strength test was carried out by design and fabricating a ROR bending strength test jig based on the Euro standard. In the strength test results, the experimental results were analyzed using the Weibull distribution, which is a statistical analysis method mainly used for evaluating the breaking strength of brittle material. Based on the analysis results, the placement spacing of the pillars proved validity for maintaining the vacuum glass gaps. 相似文献
54.
Graeme
Sabiston Il Yong Kim 《International journal for numerical methods in engineering》2020,121(19):4347-4373
A longstanding challenge in additive manufacturing (AM), the presence of void regions in additively manufactured components, causes two main issues: the enclosing of build material powder in powder bed fusion techniques and limiting tool access in critical post-processing operations to remove sacrificial support structures. As topology optimization has embraced and overcome many of the obstacles of incorporating AM constraints into the underlying numerical optimization statement, there exist few solutions that directly address this fundamental void region issue. By developing computationally efficient and effective solutions to this problem, the integration of these two advanced technologies can be fully realized. Drawing on inspiration from the principles of diffusion physics, a particle diffusion void restriction (PDVR) method is presented in this work that is capable of encouraging the optimization scheme to generate final designs that are fully accessible. Additionally, this method empowers the user to choose the type of post-processing method to clear support material (eg, three-axis or five-axis milling operations, number and orientation of part set-ups) and, therefore, quantify the level of costs associated with the post-processing operation. The PDVR optimization framework is demonstrated on multiple two- and three-dimensional test problems, with physically manufactured examples depicting the real-world benefits this method admits. 相似文献
55.
The Journal of Supercomputing - Owing to its potential applications such as military, industrial and civilian areas, most researchers and manufacturers pay attention to develop diverse smart... 相似文献
56.
57.
Intelligent Service Robotics - In this study, the goal is to efficiently and actively search for a target object in a previously unknown large-scale environment. To this end, we develop a... 相似文献
58.
Wireless Networks - Future 5G cellular networks are being designed to address the explosive traffic growth of mobile users. In emerging new wireless system paradigms, the ultra-dense network (UDN)... 相似文献
59.
60.
Scientometrics - Although scientists, like many other professionals, aspire to fame and recognition, research in the emergent field of fame and celebrity has as yet neglected to explore their fame... 相似文献