全文获取类型
收费全文 | 3338篇 |
免费 | 213篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 57篇 |
综合类 | 1篇 |
化学工业 | 892篇 |
金属工艺 | 61篇 |
机械仪表 | 107篇 |
建筑科学 | 105篇 |
矿业工程 | 6篇 |
能源动力 | 136篇 |
轻工业 | 430篇 |
水利工程 | 27篇 |
石油天然气 | 19篇 |
无线电 | 232篇 |
一般工业技术 | 494篇 |
冶金工业 | 207篇 |
原子能技术 | 17篇 |
自动化技术 | 763篇 |
出版年
2024年 | 2篇 |
2023年 | 29篇 |
2022年 | 118篇 |
2021年 | 140篇 |
2020年 | 111篇 |
2019年 | 146篇 |
2018年 | 121篇 |
2017年 | 136篇 |
2016年 | 144篇 |
2015年 | 114篇 |
2014年 | 155篇 |
2013年 | 284篇 |
2012年 | 214篇 |
2011年 | 258篇 |
2010年 | 169篇 |
2009年 | 150篇 |
2008年 | 179篇 |
2007年 | 144篇 |
2006年 | 106篇 |
2005年 | 83篇 |
2004年 | 86篇 |
2003年 | 78篇 |
2002年 | 58篇 |
2001年 | 49篇 |
2000年 | 37篇 |
1999年 | 36篇 |
1998年 | 72篇 |
1997年 | 53篇 |
1996年 | 37篇 |
1995年 | 26篇 |
1994年 | 29篇 |
1993年 | 31篇 |
1992年 | 13篇 |
1991年 | 21篇 |
1990年 | 6篇 |
1989年 | 17篇 |
1988年 | 15篇 |
1987年 | 14篇 |
1986年 | 8篇 |
1985年 | 9篇 |
1984年 | 8篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1980年 | 6篇 |
1979年 | 8篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 6篇 |
1975年 | 2篇 |
排序方式: 共有3554条查询结果,搜索用时 15 毫秒
111.
112.
A new approach for the estimation of bid-rent functions for residential location choice is proposed. The method is based on the bid-auction approach and considers that the expected maximum bid of the auction is a latent variable that can be related to observed price indicators through a measurement equation. The method has the advantage of allowing for the estimation of the parameters of the bid function that explain the heterogeneous preferences of households for location while simultaneously adjusting the expected maximum bid to reproduce realistic values. The model is applied and validated for a case study on the city of Brussels. Results show that the proposed model outperforms other methods for bid-rent estimation, both in terms of real estate prices and spatial distribution of agents, especially when detailed data describing the real estate goods and their prices is not available. 相似文献
113.
Ricardo Colomo-Palacios Israel González-Carrasco Jose Luis López-Cuadrado Antonio Trigo Joao Eduardo Varajao 《Information Systems Frontiers》2014,16(4):607-625
People in software development teams are crucial in order to gain and retain strategic advantage inside a highly competitive market. As a result, human factors have gained attention in the software industry. Software Project Managers are decisive to achieve project success. A competent project manager is capable of solving any problem that an organization may encounter, regardless of its complexity. This paper presents I-Competere which is a tool developed to forecast competence gaps in key management personnel by predicting planning and scheduling competence levels. Based on applied intelligence techniques, I-Competere allows the forecast and anticipation of competence needs thus articulating personnel development tools and techniques. The results of the test, using several artificial neural networks, are more than promising and show prediction accuracy. 相似文献
114.
Juan P. Escobedo Ellen K. Cerreta Daniel T. Martinez Carl P. Trujillo Ricardo A. Lebensohn George T. Gray III 《Metallurgical and Materials Transactions A》2014,45(13):5877-5882
The influence of temperature on the dynamic tensile behavior of Zr has been investigated. Bullet-shaped Zr samples with two different textures were dynamically extruded at room temperature and 523 K (250 °C). A higher ductility was measured for samples deformed at elevated temperature as compared to those extruded at room temperature. This difference in ductility is discussed in terms of zirconium’s ability to accommodate plastic deformation via thermally enhanced slip activity, as evidenced by examination of the deformed microstructures. 相似文献
115.
116.
117.
R.H. López‐Bañuelos F.J. Moscoso P. Ortega‐Gudiño E. Mendizabal D. Rodrigue R. González‐Núñez 《Polymer Engineering and Science》2012,52(12):2489-2497
In this study, agave fiber/linear medium density polyethylene composites were manufactured by rotational molding. A laboratory scale biaxial machine was used, where the internal air temperature during the processing cycle was measured. Two sizes of agave fibers (50 and 100 mesh) were used separately and mixed together (50/50) at concentrations varying between 0 and 15 wt%. The initial mixtures were obtained by dry blending, rotomolded under different operation conditions (oven temperature, processing cycle time, and rotational speeds), and the final pieces were compared. For each process condition, a complete morphological analysis was performed to relate with mechanical properties in terms of tensile, impact, and flexural strength. The results show that there is an optimum fiber concentration around 10%, and blending fiber sizes gave better tensile properties than using each size alone. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers 相似文献
118.
119.
120.
Leonardo Crauss Daronco Valter Roesler José Valdeni de Lima Ricardo Balbinot 《Multimedia Tools and Applications》2012,61(3):571-597
This paper presents a study of quality on scalable video sequences coded using the scalable extension of the H.264 standard (SVC). A group of experiments was performed to measure, primarily, the effects that transmission instability has in the quality of the videos and the relationship among three scalability methods (spatial, temporal and quality) in terms of quality. A set of experiments was performed to measure the subjective quality using the ACR-HRR methodology and recommendations from ITU-R Rec. BT.500 and ITU-T Rec. P.910. The results show that the amount of instability is not as important as just the presence of instability, that video quality can be deteriorated due to instability and that temporal scalability usually produces videos with worse quality than spatial and quality scalabilities. 相似文献