全文获取类型
收费全文 | 17117篇 |
免费 | 1181篇 |
国内免费 | 558篇 |
专业分类
电工技术 | 753篇 |
技术理论 | 1篇 |
综合类 | 903篇 |
化学工业 | 3303篇 |
金属工艺 | 754篇 |
机械仪表 | 944篇 |
建筑科学 | 1056篇 |
矿业工程 | 388篇 |
能源动力 | 450篇 |
轻工业 | 1273篇 |
水利工程 | 269篇 |
石油天然气 | 683篇 |
武器工业 | 87篇 |
无线电 | 1785篇 |
一般工业技术 | 2462篇 |
冶金工业 | 1318篇 |
原子能技术 | 180篇 |
自动化技术 | 2247篇 |
出版年
2024年 | 66篇 |
2023年 | 260篇 |
2022年 | 379篇 |
2021年 | 589篇 |
2020年 | 494篇 |
2019年 | 387篇 |
2018年 | 470篇 |
2017年 | 512篇 |
2016年 | 465篇 |
2015年 | 570篇 |
2014年 | 746篇 |
2013年 | 1059篇 |
2012年 | 965篇 |
2011年 | 1008篇 |
2010年 | 910篇 |
2009年 | 832篇 |
2008年 | 800篇 |
2007年 | 864篇 |
2006年 | 817篇 |
2005年 | 659篇 |
2004年 | 501篇 |
2003年 | 554篇 |
2002年 | 626篇 |
2001年 | 484篇 |
2000年 | 395篇 |
1999年 | 433篇 |
1998年 | 433篇 |
1997年 | 351篇 |
1996年 | 294篇 |
1995年 | 244篇 |
1994年 | 205篇 |
1993年 | 162篇 |
1992年 | 129篇 |
1991年 | 109篇 |
1990年 | 103篇 |
1989年 | 89篇 |
1988年 | 67篇 |
1987年 | 53篇 |
1986年 | 55篇 |
1985年 | 51篇 |
1984年 | 42篇 |
1983年 | 44篇 |
1982年 | 39篇 |
1981年 | 44篇 |
1980年 | 45篇 |
1979年 | 39篇 |
1978年 | 37篇 |
1977年 | 38篇 |
1976年 | 43篇 |
1975年 | 44篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Wan Hang Mao Yingzhu Cai Yanpeng Li Ran Feng Jingjie Yang Huixia 《Engineering with Computers》2022,38(4):3169-3184
Engineering with Computers - Aerated flow characterized by complex mass transfer processes with multiple hydraulic properties is a common enviro-hydraulics phenomenon, which have a variety of... 相似文献
42.
Ma Chao Wan Minjie Xu Yunkai Ren Kan Qian Weixian Chen Qian Gu Guohua 《Applied Intelligence》2022,52(3):2785-2800
Applied Intelligence - Infrared target tracking plays an important role in both civil and military fields. The main challenges in designing a robust and high-precision tracker for infrared... 相似文献
43.
Hollow Pd/MOF Nanosphere with Double Shells as Multifunctional Catalyst for Hydrogenation Reaction 下载免费PDF全文
Mingming Wan Xinlu Zhang Meiyan Li Bo Chen Jie Yin Haichao Jin Lin Lin Chao Chen Ning Zhang 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(38)
A new type of hollow nanostructure featured double metal‐organic frameworks shells with metal nanoparticles (MNPs) is designed and fabricated by the methods of ship in a bottle and bottle around the ship. The nanostructure material, hereinafter denoted as Void@HKUST‐1/Pd@ZIF‐8, is confirmed by the analyses of photograph, transmission electron microscopy, scanning electron microscopy, powder X‐ray diffraction, inductively coupled plasma, and N2 sorption. It possesses various multifunctionally structural characteristics such as hollow cavity which can improve mass transfer, the adjacent of the inner HKUST‐1 shell to the void which enables the matrix of the shell to host and well disperse MNPs, and an outer ZIF‐8 shell which acts as protective layer against the leaching of MNPs and a sieve to guarantee molecular‐size selectivity. This makes the material eligible candidates for the heterogeneous catalyst. As a proof of concept, the liquid‐phase hydrogenation of olefins with different molecular sizes as a model reaction is employed. It demonstrates the efficient catalytic activity and size‐selectivity of Void@HKUST‐1/Pd@ZIF‐8. 相似文献
44.
钢卷尺全自动检测装置由5m长的高稳定性大理石平台、加载装置、自动卷送带装置、精确的自动对焦机器视觉系统以及计算机控制系统等组成。本文将对自动对焦机器视觉系统进行详细介绍。 相似文献
45.
Zan Wu Zhang Qiaochu Xu Hu Liao Fuyou Guo Zhongxun Deng Jianan Wan Jing Zhu Hao Chen Lin Sun Qingqing Ding Shijin Zhou Peng Bao Wenzhong Zhang David Wei 《Nano Research》2018,11(7):3739-3745
Nano Research - A spin-coating method was applied to obtain thinner and smoother PEO/LiClO4 polymer electrolyte films (EFs) with a lower level of crystallization than those obtained using a... 相似文献
46.
Autonomous topological modeling of a home environment and topological localization using a sonar grid map 总被引:1,自引:0,他引:1
This paper presents a method of autonomous topological modeling and localization in a home environment using only low-cost
sonar sensors. The topological model is extracted from a grid map using cell decomposition and normalized graph cut. The autonomous
topological modeling involves the incremental extraction of a subregion without predefining the number of subregions. A method
of topological localization based on this topological model is proposed wherein a current local grid map is compared with
the original grid map. The localization is accomplished by obtaining a node probability from a relative motion model and rotational
invariant grid-map matching. The proposed method extracts a well-structured topological model of the environment, and the
localization provides reliable node probability even when presented with sparse and uncertain sonar data. Experimental results
demonstrate the performance of the proposed topological modeling and localization in a real home environment. 相似文献
47.
48.
Ilias Diakonikolas Homin K. Lee Kevin Matulef Rocco A. Servedio Andrew Wan 《Algorithmica》2011,61(3):580-605
We give the first algorithm that is both query-efficient and time-efficient for testing whether an unknown function f:{0,1}
n
→{−1,1} is an s-sparse GF(2) polynomial versus ε-far from every such polynomial. Our algorithm makes poly(s,1/ε) black-box queries to f and runs in time n⋅poly(s,1/ε). The only previous algorithm for this testing problem (Diakonikolas et al. in Proceedings of the 48th Annual Symposium on
Foundations of Computer Science, FOCS, pp. 549–558, 2007) used poly(s,1/ε) queries, but had running time exponential in s and super-polynomial in 1/ε. 相似文献
49.
Albert Visser 《Theoretical computer science》2011,412(28):3404-3411
In this paper we study an alternative way of treating Polish notation. Instead of proving unique reading for a well-behaved set of terms, we interpret any string of the alphabet in a monoid that extends, in a specifiable sense, the given algebra of functions. 相似文献
50.
The implementation of product development process management (PDPM) is an effective means of developing products with higher quality in shorter lead time. It is argued in this paper that product, data, person and activity are basic factors in PDPM With detailed analysis of these basic factors and their relations in product developmed process, all product development activities are considered as tasks and the management of product development process is regarded as the management of task execution A task decomposition based product development model is proposed with methods of constructing task relation matrix from layer model and constraint model resulted from task decomposition. An algorithm for constructing directed task graph is given and is used in the management of tasks. Finally, the usage and limitation of the proposed PDPM model is given with further work proposed. 相似文献