全文获取类型
收费全文 | 2511篇 |
免费 | 191篇 |
国内免费 | 101篇 |
专业分类
电工技术 | 208篇 |
技术理论 | 1篇 |
综合类 | 155篇 |
化学工业 | 112篇 |
金属工艺 | 75篇 |
机械仪表 | 361篇 |
建筑科学 | 35篇 |
矿业工程 | 25篇 |
能源动力 | 36篇 |
轻工业 | 67篇 |
水利工程 | 12篇 |
石油天然气 | 46篇 |
武器工业 | 22篇 |
无线电 | 296篇 |
一般工业技术 | 159篇 |
冶金工业 | 61篇 |
原子能技术 | 18篇 |
自动化技术 | 1114篇 |
出版年
2024年 | 7篇 |
2023年 | 38篇 |
2022年 | 40篇 |
2021年 | 55篇 |
2020年 | 69篇 |
2019年 | 67篇 |
2018年 | 46篇 |
2017年 | 58篇 |
2016年 | 53篇 |
2015年 | 58篇 |
2014年 | 129篇 |
2013年 | 124篇 |
2012年 | 151篇 |
2011年 | 159篇 |
2010年 | 122篇 |
2009年 | 124篇 |
2008年 | 134篇 |
2007年 | 198篇 |
2006年 | 173篇 |
2005年 | 149篇 |
2004年 | 150篇 |
2003年 | 123篇 |
2002年 | 86篇 |
2001年 | 70篇 |
2000年 | 65篇 |
1999年 | 53篇 |
1998年 | 51篇 |
1997年 | 52篇 |
1996年 | 32篇 |
1995年 | 26篇 |
1994年 | 35篇 |
1993年 | 18篇 |
1992年 | 6篇 |
1991年 | 15篇 |
1990年 | 7篇 |
1989年 | 7篇 |
1988年 | 11篇 |
1986年 | 6篇 |
1985年 | 4篇 |
1984年 | 7篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1977年 | 2篇 |
1975年 | 2篇 |
1965年 | 1篇 |
1964年 | 1篇 |
1959年 | 2篇 |
排序方式: 共有2803条查询结果,搜索用时 84 毫秒
1.
By leveraging the secret data coding using the remainder storage based exploiting modification direction (RSBEMD), and the pixel change operation recording based on multi-segment left and right histogram shifting, a novel reversible data hiding (RHD) scheme is proposed in this paper. The secret data are first encoded by some specific pixel change operations to the pixels in groups. After that, multi-segment left and right histogram shifting based on threshold manipulation is implemented for recording the pixel change operations. Furthermore, a multiple embedding policy based on chess board prediction (CBP) and threshold manipulation is put forward, and the threshold can be adjusted to achieve adaptive data hiding. Experimental results and analysis show that it is reversible and can achieve good performance in capacity and imperceptibility compared with the existing methods. 相似文献
2.
Wesley P. Chan Hiroto Mizohana Xiangyu Chen Yasuto Shiigi Yoshiyuki Yamanoue Masaki Nagatsuka Masayuki Inaba 《野外机器人技术杂志》2019,36(1):17-33
The use of field robots can greatly decrease the amount of time, effort, and associated risk compared to if human workers were to carryout certain tasks such as disaster response. However, transportability and reliability remain two main issues for most current robot systems. To address the issue of transportability, we have developed a lightweight modularizable platform named AeroArm. To address the issue of reliability, we utilize a multimodal sensing approach, combining the use of multiple sensors and sensor types, and the use of different detection algorithms, as well as active continuous closed‐loop feedback to accurately estimate the state of the robot with respect to the environment. We used Challenge 2 of the 2017 Mohammed Bin Zayed International Robotics Competition as an example outdoor manipulation task, demonstrating the capabilities of our robot system and approach in achieving reliable performance in the fields, and ranked fifth place internationally in the competition. 相似文献
3.
Ken Kanazawa Shoji Yoshida Hidemi Shigekawa Shinji Kuroda 《Science and Technology of Advanced Materials》2015,16(1)
The reconstructed surface structure of the II–VI semiconductor ZnTe (110), which is a promising material in the research field of semiconductor spintronics, was studied by scanning tunneling microscopy/spectroscopy (STM/STS). First, the surface states formed by reconstruction by the charge transfer of dangling bond electrons from cationic Zn to anionic Te atoms, which are similar to those of IV and III–V semiconductors, were confirmed in real space. Secondly, oscillation in tunneling current between binary states, which is considered to reflect a conformational change in the topmost Zn–Te structure between the reconstructed and bulk-like ideal structures, was directly observed by STM. Third, using the technique of charge injection, a surface atomic structure was successfully fabricated, suggesting the possibility of atomic-scale manipulation of this widely applicable surface of ZnTe. 相似文献
4.
We model developable surfaces by wrapping a planar figure around cones and cylinders. Complicated developables can be constructed by successive mappings using cones and cylinders of different sizes and shapes. We also propose an intuitive control mechanism, which allows a user to select an arbitrary point on the planar figure and move it to a new position. Numerical techniques are then used to find a cone or cylinder that produces the required mapping. Several examples demonstrate the effectiveness of our technique. 相似文献
5.
本文介绍一种智能型、高精度PWR控制器SA4828,其控制实行全数字化产生三相脉宽调制波形.本文采用此器件设计大功率直流电源应用于22KW直流电机测试,对感性负载表现出具有纹波小,响应迅速、硬件电路简洁、控制简单易于编写的优点。 相似文献
6.
高肖林 《中国材料科技与设备》2007,4(2):92-94
中厚板厂3500mm精轧机快速换辊自控系统,集可编程序控制器、变频传动技术、液压控制于一体。实现了工作辊、支承辊准确、快速地更换。通过网络技术与其他控制系统进行数据交换、操作及连锁,使轧制生产线实现了全自动化轧制,不仅改善了工人的劳动强度,还提高了产品的产量及质量,取得了巨大的社会效益及经济效益。 相似文献
7.
8.
The objective of this note is to propose a method for stabilization of structurally fixed modes in expansions of LTI dynamic systems in the scope of overlapping decentralized control design based on the expansion/contraction framework, enabling successful design for a broader class of problems than considered so far. The method is based on a judicious choice of complementary matrices in the expanded space. Numerical examples are provided to illustrate simplicity and efficiency of the proposed approach. 相似文献
9.
在测定 2 0CrMnTi、4 0MnBH、2 0MnVBH钢淬透性及试样的化学成分基础之上 ,利用计算机采用逐步回归分析方法进行了回归运算 ,得到淬透性与化学成分的关系———回归方程 ,根据回归方程求出了不同窄淬透带规格所对应控制的化学成分范围 相似文献
10.
Repetitive processes are a distinct class of 2D systems (i.e. information propagation in two independent directions) of both systems theoretic and applications interest. They cannot be controlled by direct extension of existing techniques from either standard (termed 1D here) or 2D systems theory. In this paper, we exploit their unique physical structure to show how two term, i.e. proportional plus integral (or PI) action, can be used to control these processes to produce desired behavior (as opposed to just stability). 相似文献