全文获取类型
| 收费全文 | 11821篇 |
| 免费 | 523篇 |
| 国内免费 | 467篇 |
专业分类
| 电工技术 | 628篇 |
| 综合类 | 626篇 |
| 化学工业 | 1085篇 |
| 金属工艺 | 418篇 |
| 机械仪表 | 1607篇 |
| 建筑科学 | 1248篇 |
| 矿业工程 | 329篇 |
| 能源动力 | 416篇 |
| 轻工业 | 704篇 |
| 水利工程 | 199篇 |
| 石油天然气 | 522篇 |
| 武器工业 | 61篇 |
| 无线电 | 807篇 |
| 一般工业技术 | 621篇 |
| 冶金工业 | 258篇 |
| 原子能技术 | 157篇 |
| 自动化技术 | 3125篇 |
出版年
| 2025年 | 26篇 |
| 2024年 | 56篇 |
| 2023年 | 103篇 |
| 2022年 | 136篇 |
| 2021年 | 191篇 |
| 2020年 | 201篇 |
| 2019年 | 142篇 |
| 2018年 | 244篇 |
| 2017年 | 232篇 |
| 2016年 | 325篇 |
| 2015年 | 421篇 |
| 2014年 | 709篇 |
| 2013年 | 840篇 |
| 2012年 | 855篇 |
| 2011年 | 941篇 |
| 2010年 | 654篇 |
| 2009年 | 639篇 |
| 2008年 | 531篇 |
| 2007年 | 624篇 |
| 2006年 | 570篇 |
| 2005年 | 574篇 |
| 2004年 | 491篇 |
| 2003年 | 478篇 |
| 2002年 | 424篇 |
| 2001年 | 311篇 |
| 2000年 | 294篇 |
| 1999年 | 315篇 |
| 1998年 | 253篇 |
| 1997年 | 208篇 |
| 1996年 | 200篇 |
| 1995年 | 191篇 |
| 1994年 | 122篇 |
| 1993年 | 82篇 |
| 1992年 | 76篇 |
| 1991年 | 58篇 |
| 1990年 | 43篇 |
| 1989年 | 34篇 |
| 1988年 | 38篇 |
| 1987年 | 23篇 |
| 1986年 | 14篇 |
| 1985年 | 27篇 |
| 1984年 | 26篇 |
| 1983年 | 16篇 |
| 1982年 | 23篇 |
| 1981年 | 16篇 |
| 1980年 | 7篇 |
| 1979年 | 9篇 |
| 1978年 | 3篇 |
| 1976年 | 10篇 |
| 1955年 | 1篇 |
排序方式： 共有10000条查询结果，搜索用时 0 毫秒
101.
《Materials and Manufacturing Processes》2012,27(12):1479-1486
A new fabrication module to help dregs discharge on a free-form surface as a super finish module is demonstrated using an effective design mechanism and ultrasonic energy sent to the electrolyte. The proposed process increases the performance of the pulsed-electrochemical finishing. The outer shell of a toy plane was used as a workpiece sample in the current experiment. Four types of design electrodes were used and supplied with both continuous and direct pulsed current in the experiment. The design features of the manufacturing mechanism using pulse-electrochemical finishing with ultrasonic assistance (UAPEF) are of major interest. An electrode with a small end radius is associated with higher current density, and provides larger discharge space and better finish. However, the pin-type electrode provides the largest discharge space and performs the best among the discussed electrodes. The super finish of UAPEF after die casting saves the need for hand or machine polishing and requires a shorter time to make the casting surfaces smooth and bright. An effective and low-cost super finish module for the freeform surface of castings that use satisfactory electrode geometry and ultrasonic assistance is presented. The proposed ultrasonic assistance has proven effective in promoting the performance of design electrodes. 相似文献
102.
《Materials and Manufacturing Processes》2012,27(2):182-187
The effects of key process conditions on the protrusion of via conductors and warpage of low temperature co-fired ceramic (LTCC) substrates were investigated using the design of experiments and analysis of variance. The results revealed that tape thickness, via size and coining pressure had highly significant effects and the interaction of via size and coining pressure had a significant effect on the via protrusion heights of the LTCC samples. A combination of via size of 0.12 mm, raw tape thickness of 0.254 mm and coining pressure of 50 MPa produced minimized protrusion. Tape thickness, coining pressure and the interaction of them had highly significant effects on the warpage of the LTCC samples. A combination of tape thickness of 0.127 mm and coining pressure of 50 MPa produced minimized warpage. A combination of the factor settings was also recommended for obtaining low heights of both protrusion and warpage. 相似文献
103.
《Materials and Manufacturing Processes》2012,27(8):858-864
Composite materials are used in varieties of applications and are mainly used in structural components. Drilling is one of the important operations in composite structure, often a final operation during assembly. Delaminations in drilling of composite structures are a serious problem and lead to rejection and impose heavy loss. In the present investigation, delamianation associated with drilling has been studied using experimental design approach. Two different cutting tools were tried for experimentation. The experiments were conducted by using high-speed steel-made twist drill and 4-flute cutter. Empirical models were developed for predicting delamination factor in drilling GFRP composites. Regression analysis and analysis of variance (ANOVA) were used for analysis. The adequacies of the developed models have been verified by calculating correlation coefficient. The effect of cutting parameters on drilling such as spindle speed, feed, and their interactions are studied in detail. 相似文献
104.
《International Journal of Pavement Engineering》2012,13(1):51-58
Mechanistic analysis of jointed concrete pavements has often considered only traffic loading in tensile stress calculation. The analysis is often reduced to a single or dual wheel load positioned at a free slab edge. More advanced analyses have included environmental loading, but this is usually limited to a linear temperature differential through the slab. This type of analysis usually predicts bottom-up transverse cracking in the center of the slab. However, field data has indicated that other failure modes can also occur. This paper quantitatively demonstrates how the failure mode of jointed concrete pavements can be transverse, corner, or longitudinal cracking, originating at either the top or bottom of the slab. The failure mode depends on the loading, slab geometry, environment, and material properties. The differential drying shrinkage of the concrete was found to be one of the most influential parameters in reproducing the observed failure modes of in-situ concrete pavements. 相似文献
105.
106.
107.
108.
109.
110.