全文获取类型
收费全文 | 112830篇 |
免费 | 15087篇 |
国内免费 | 7884篇 |
专业分类
电工技术 | 10124篇 |
技术理论 | 2篇 |
综合类 | 11205篇 |
化学工业 | 15051篇 |
金属工艺 | 7471篇 |
机械仪表 | 8229篇 |
建筑科学 | 8775篇 |
矿业工程 | 4402篇 |
能源动力 | 3238篇 |
轻工业 | 12100篇 |
水利工程 | 3327篇 |
石油天然气 | 4241篇 |
武器工业 | 1605篇 |
无线电 | 12333篇 |
一般工业技术 | 10479篇 |
冶金工业 | 4476篇 |
原子能技术 | 1830篇 |
自动化技术 | 16913篇 |
出版年
2025年 | 6篇 |
2024年 | 2020篇 |
2023年 | 2260篇 |
2022年 | 4746篇 |
2021年 | 5865篇 |
2020年 | 4461篇 |
2019年 | 3239篇 |
2018年 | 3531篇 |
2017年 | 3981篇 |
2016年 | 3522篇 |
2015年 | 5312篇 |
2014年 | 6815篇 |
2013年 | 7803篇 |
2012年 | 9286篇 |
2011年 | 9619篇 |
2010年 | 8991篇 |
2009年 | 8375篇 |
2008年 | 8375篇 |
2007年 | 8110篇 |
2006年 | 6809篇 |
2005年 | 5534篇 |
2004年 | 3994篇 |
2003年 | 2788篇 |
2002年 | 2580篇 |
2001年 | 2183篇 |
2000年 | 1858篇 |
1999年 | 1082篇 |
1998年 | 466篇 |
1997年 | 423篇 |
1996年 | 379篇 |
1995年 | 304篇 |
1994年 | 224篇 |
1993年 | 185篇 |
1992年 | 133篇 |
1991年 | 104篇 |
1990年 | 71篇 |
1989年 | 87篇 |
1988年 | 58篇 |
1987年 | 27篇 |
1986年 | 31篇 |
1985年 | 12篇 |
1984年 | 23篇 |
1983年 | 10篇 |
1982年 | 7篇 |
1981年 | 20篇 |
1980年 | 30篇 |
1979年 | 21篇 |
1977年 | 2篇 |
1959年 | 16篇 |
1951年 | 17篇 |
排序方式: 共有10000条查询结果,搜索用时 13 毫秒
61.
运用多模型自适应控制技术,针对空分系统的整体能耗优化,就空分系统模型集的建立、控制器的设计、切换算法等方面进行了分析。空分系统作为一个实时变化的有机整体,在整体运行过程中存在的操作环境改变对系统的影响,当系统发生变化及波动时,根据相应切换算法切换到可以满足生产变化的模型,采用适合的控制器,以达到实时监控、安全生产的效果,最大限度地优化了系统运行。 相似文献
62.
The suitability of computational simulation of the Belousov–Zhabotinskii oscillating chemical reaction by differential kinetic methodology for resolving nonlinear multi-component system is demonstrated in this work. According to the Field–KÖrÖs–Noyes mechanism and the Oregonator model, the change of the concentrations of HBrO2, bromide ion and cerium ion are simulated. The results of computational simulation are consistent with experimental results very well. At the same time, the effect of variables and parameters, especially the rate constant on the oscillation curve, are investigated deeply. A simple method of estimating rate constants is obtained through simulation the concentrations of key components of the system, and then comparison the simulation results with the experimental ones. The reasonable rate constant is also proposed. 相似文献
63.
Global robust output regulation of lower triangular systems with unknown control direction 总被引:3,自引:0,他引:3
This paper presents the solvability conditions for the global robust output regulation problem for lower triangular nonlinear systems assuming the control direction is unknown. The approach used is an integration of the robust stabilization technique and Nussbaum gain technique. 相似文献
64.
65.
Jine Zhang Xiaobing Chen Mengqin Wang Qinghua Zhang Wenxiao Shi Xiaozhi Zhan Meng Zhao Zhe Li Jie Zheng Hui Zhang Furong Han Huaiwen Yang Tao Zhu Banggui Liu Fengxia Hu Baogen Shen Yuansha Chen Yue Zhang Yunzhong Chen Weisheng Zhao Jirong Sun 《Advanced functional materials》2023,33(41):2306434
Ferromagnetic materials with a strong spin-orbit coupling (SOC) have attracted much attention in recent years because of their exotic properties and potential applications in energy-efficient spintronics. However, such materials are scarce in nature. Here, a proximity-induced paramagnetic to ferromagnetic transition for the heavy transition metal oxide CaRuO3 in (001)-(LaMnO3/CaRuO3) superlattices is reported. Anomalous Hall effect is observed in the temperature range up to 180 K. Maximal anomalous Hall conductivity and anomalous Hall angle are as large as ∼15 Ω−1 cm−1 and ∼0.93%, respectively, by one to two orders of magnitude larger than those of the typical 3d ferromagnetic oxides such as La0.67Sr0.33MnO3. Density functional theory calculations indicate the existence of avoid band crossings in the electronic band structure of the ferromagnetic CRO layer, which enhances Berry curvature thus strong anomalous Hall effects. Further evidences from polarized neutron reflectometry show that the CaRuO3 layers are in a fully ferromagnetic state (∼0.8 μB/Ru), in sharp contrast to the proximity-induced canted antiferromagnetic state in 5d oxides SrIrO3 and CaIrO3 (∼0.1 μB/Ir). More than that, the magnetic anisotropy of the (001)-(LaMnO3/CaRuO3) superlattices is eightfold symmetric, showing potential applications in the technology of multistate data storage. 相似文献
66.
Neural Computing and Applications - In this paper, the state estimation problem is investigated for a class of discrete-time complex-valued neural networks (CVNNs) with mixed time delays. We... 相似文献
67.
Applied Intelligence - The henry gas solubility optimization (HGSO) is a new nature-inspired algorithm that mimics Henry Gas Solubility to solve global optimization problems. The main changes of... 相似文献
68.
Applied Intelligence - Implicit discourse relation classification is one of the most challenging tasks in discourse parsing. Without connectives as linguistic clues, classifying discourse relations... 相似文献
69.
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
70.