全文获取类型
收费全文 | 12663篇 |
免费 | 964篇 |
国内免费 | 456篇 |
专业分类
电工技术 | 641篇 |
综合类 | 809篇 |
化学工业 | 2202篇 |
金属工艺 | 744篇 |
机械仪表 | 762篇 |
建筑科学 | 1017篇 |
矿业工程 | 353篇 |
能源动力 | 325篇 |
轻工业 | 592篇 |
水利工程 | 193篇 |
石油天然气 | 803篇 |
武器工业 | 73篇 |
无线电 | 1437篇 |
一般工业技术 | 1724篇 |
冶金工业 | 692篇 |
原子能技术 | 119篇 |
自动化技术 | 1597篇 |
出版年
2024年 | 68篇 |
2023年 | 273篇 |
2022年 | 336篇 |
2021年 | 504篇 |
2020年 | 414篇 |
2019年 | 327篇 |
2018年 | 412篇 |
2017年 | 438篇 |
2016年 | 409篇 |
2015年 | 449篇 |
2014年 | 586篇 |
2013年 | 681篇 |
2012年 | 759篇 |
2011年 | 830篇 |
2010年 | 677篇 |
2009年 | 678篇 |
2008年 | 695篇 |
2007年 | 621篇 |
2006年 | 679篇 |
2005年 | 621篇 |
2004年 | 421篇 |
2003年 | 353篇 |
2002年 | 330篇 |
2001年 | 252篇 |
2000年 | 286篇 |
1999年 | 335篇 |
1998年 | 281篇 |
1997年 | 274篇 |
1996年 | 230篇 |
1995年 | 178篇 |
1994年 | 164篇 |
1993年 | 125篇 |
1992年 | 99篇 |
1991年 | 71篇 |
1990年 | 78篇 |
1989年 | 31篇 |
1988年 | 37篇 |
1987年 | 24篇 |
1986年 | 19篇 |
1985年 | 5篇 |
1984年 | 7篇 |
1983年 | 8篇 |
1982年 | 6篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Xiaobin Zou Haikuan Liang Yan Li Yichao Zou Fei Tian Yong Sun Chengxin Wang 《Advanced functional materials》2023,33(18):2213807
Following logic in the silicon semiconductor industry, the existence of native oxide and suitable fabrication technology is essential for 2D semiconductors in planar integronics, which are surface-sensitive to typical coating technologies. To date, very few types of integronics are found to possess this feature. Herein, the 2D Bi2O2Te developed recently is reported to possess large-area synthesis and controllable thermal oxidation behavior toward single-crystal native oxides. This shows that surface-adsorbed oxygen atoms are inclined to penetrate across [Bi2O2]n2n+ layers and bond with the underlying [Te]n2n− at elevated temperatures, transforming directly into [TeO4]n2n− with the basic architecture remaining stable. The oxide can be adjusted to form in an accurate layer-by-layer manner with a low-stress sharp interface. The native oxide Bi2TeO6 layer (bandgap of ≈2.9 eV) exhibits visible-light transparency and is compatible with wet-chemical selective etching technology. These advances demonstrate the potential of Bi2O2Te in planar-integrated functional nanoelectronics such as tunnel junction devices, field-effect transistors, and memristors. 相似文献
12.
Applied Intelligence - In recent years, person re-identification (re-ID) has become a widespread research topic that focuses on retrieving target pedestrians from a set of images, typically taken... 相似文献
13.
14.
15.
Lu Gui-Fu Zou Jian Wang Yong Wang Zhongqun 《Multimedia Tools and Applications》2017,76(14):15801-15816
Multimedia Tools and Applications - Null space based linear discriminant analysis (NSLDA) is a well-known feature extraction method, which can make use of the most discriminant information in the... 相似文献
16.
International Journal of Control, Automation and Systems - This paper concerns the attitude control problem of a 3D rigid pendulum based on dynamic T-S fuzzy neural model. A generalized 3D rigid... 相似文献
17.
海面高程的传递是水准测量中的难题.以宁波市象山县某围堤工程变形测量为例,对全站仪进行跨海面高程测量进行了成功应用,并用GPS拟合高程测量方法和平均海平面法进行了验证,结果合理. 相似文献
18.
A detailed transmission electron microscope (TEM) study has been conducted to investigate the microstructures of the Zr51Cu20.7Ni12Al16.3 metallic glass formed at different cooling rates. It has been found that the most competitive crystalline phase to the amorphous structure is an oxygen-stabilized FCC NiZr2-type phase, which in turn acts as the leading phase to trigger the formation of other crystalline phases in the slow-cooled alloy. 相似文献
19.
An interpolation model to accelerate the frequency-domain response calculation of grounding systems using the method of moments 总被引:1,自引:0,他引:1
The transient characteristics of grounding systems are essential for their designs and related electromagnetic-compatibility problems in power systems. Although the method of moments (MoM) is a popular way to analyze the characteristics of grounding systems, it is time-consuming. In this paper, a two-stage method is presented to construct fitted models of the frequency-domain responses of grounding systems to accelerate the calculations of the MoM. In the first stage, the adaptive model-based parameter estimation is used to adaptively choose the most valuable frequency sampling points to construct the initial fitted functions, and then the fitted functions are adjusted in the second stage by comparing the fitted results with those computed by the first principle model at some points. The validation was achieved by a comparison of the numerical results and those obtained by inverse fast Fourier transformation. 相似文献
20.
Quanbo Zou Zhimin Tan Zhenfeng Wang Jiangtao Pang Xin Qian Qingxin Zhang Rongming Lin Sung Yi Haiqing Gong Litian Liu Zhijian Li 《Journal of microelectromechanical systems》1998,7(2):224-234
A novel principle “electret” microphone, i.e., floating electrode electret microphone, is proposed and implemented in this study. Single-chip fabrication and corrugation technique are used in the design and fabrication of the microphone. The floating electrode is encapsulated by highly insulated materials to ensure that there is no electric-leakage passage between the floating electrode and the electrodes of the microphone. Net-free electronic charges (not “bonded” charges as in traditional electret) in the floating electrode can excite the electric field, which is similar to that of the traditional electret. The floating electrode can be easily charged by use of the “hot” electron technique, available using the avalanche breakdown of the p+-n junction. Therefore, the electret microphone is rechargeable, which can greatly increase the lifetime of the device. The preamplifier has been on-chip integrated in a junction-field-effect transistor (JFET) source-follower type with resistors by use of ion implantation. Electret charges are banded in a deep potential trap, thus, this microphone can operate at a high temperature (as high as 300°C) and has high stability and reliability. Experiments show that the prototype has a 3-mV/Pa sensitivity and a larger than 21-kHz frequency bandwidth in a 1 mm ×1-mm diaphragm area. Microphone performance can be further improved by optimized process and design. The fabrication is completely integrated-circuit (IC) compatible, hence, the microphone shows promise in integrated acoustic systems 相似文献