全文获取类型
收费全文 | 73369篇 |
免费 | 8329篇 |
国内免费 | 4683篇 |
专业分类
电工技术 | 6263篇 |
技术理论 | 7篇 |
综合类 | 5485篇 |
化学工业 | 11535篇 |
金属工艺 | 4265篇 |
机械仪表 | 4679篇 |
建筑科学 | 5886篇 |
矿业工程 | 2451篇 |
能源动力 | 2093篇 |
轻工业 | 5466篇 |
水利工程 | 1754篇 |
石油天然气 | 3797篇 |
武器工业 | 798篇 |
无线电 | 9047篇 |
一般工业技术 | 8479篇 |
冶金工业 | 3087篇 |
原子能技术 | 736篇 |
自动化技术 | 10553篇 |
出版年
2024年 | 511篇 |
2023年 | 1751篇 |
2022年 | 3272篇 |
2021年 | 4498篇 |
2020年 | 3243篇 |
2019年 | 2479篇 |
2018年 | 2584篇 |
2017年 | 2862篇 |
2016年 | 2568篇 |
2015年 | 3475篇 |
2014年 | 4199篇 |
2013年 | 4799篇 |
2012年 | 5516篇 |
2011年 | 5781篇 |
2010年 | 4734篇 |
2009年 | 4490篇 |
2008年 | 4434篇 |
2007年 | 4095篇 |
2006年 | 3747篇 |
2005年 | 3245篇 |
2004年 | 2089篇 |
2003年 | 1708篇 |
2002年 | 1668篇 |
2001年 | 1368篇 |
2000年 | 1263篇 |
1999年 | 1209篇 |
1998年 | 885篇 |
1997年 | 731篇 |
1996年 | 694篇 |
1995年 | 563篇 |
1994年 | 510篇 |
1993年 | 320篇 |
1992年 | 253篇 |
1991年 | 196篇 |
1990年 | 147篇 |
1989年 | 111篇 |
1988年 | 85篇 |
1987年 | 61篇 |
1986年 | 61篇 |
1985年 | 24篇 |
1984年 | 28篇 |
1983年 | 14篇 |
1982年 | 28篇 |
1981年 | 14篇 |
1980年 | 20篇 |
1979年 | 13篇 |
1978年 | 5篇 |
1976年 | 4篇 |
1959年 | 8篇 |
1951年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Various molecular docking software packages are available for modeling interactions between small molecules and proteins.However,there have been few reports of modeling the interactions between metal ions and metalloproteins.In this study,the AutoDock package was employed to example docking into a di-iron binding protein,bacterioferritin.Each binding site of this protein was tested for docking with iron ions.Blind docking experiments showed that all docking conformations converged into two clusters,one for internal iron binding in sites within the metalloprotein and the other for external iron binding on the protein surface.Local docking experiments showed that there were significant differences between two internal iron binding sites.Docking at one site gave a reasonable root-mean-square deviation(RMSD) distribution with relatively low binding energy.Analysis of the binding mode quality for this site revealed that more than half of the docking conformations were categorized as having good binding geometry,while no good conformations were found for the other site.Further investigations indicated that coordinating water molecules contributed to the stability of binding geometries.This study provides an empirical approach towards the study of molecular docking in metalloproteins. 相似文献
72.
73.
74.
主要介绍基于便携式设备的RDS调频收音模块的设计,着重讲述了有关FM接收、RDS数据接收与音频处理等方面的应用电路。 相似文献
75.
A shift-invariant neural network that uses the translation-invariant property of the modulus Fourier spectra with the heteroassociation interpattern association memory is proposed. A binary encoding of a spectral sampling of the training set is used to preserve the main features. Computer simulations and experimental demonstrations are provided that show the shift-invariant property of the proposed optical neural network. 相似文献
76.
Yin Lifeng Kong Yanggang Guo Mingkang Zhang Xingyu Yan Wenlong Zhang Hua 《Magma (New York, N.Y.)》2023,36(4):651-658
Magnetic Resonance Materials in Physics, Biology and Medicine - This study aims to present a radiomic application in diagnosing the long head of biceps (LHB) tendinitis. Moreover, we evaluated... 相似文献
77.
Jiacheng Yin Na Li Ming Liu Zhigang Li Xuemin Wang Mingren Cheng Ming Zhong Wei Li Yunhua Xu Xian-He Bu 《Advanced functional materials》2023,33(21):2211950
Organic redox-active materials are promising electrode candidates for lithium-ion batteries by virtue of their designable structure and cost-effectiveness. However, their poor electrical conductivity and high solubility in organic electrolytes limit the device's performance and practical applications. Herein, the π-conjugated nitrogen-containing heteroaromatic molecule hexaazatriphenylene (HATN) is strategically embedded with redox-active centers in the skeleton of a Cu-based 2D conductive metal–organic framework (2D c-MOF) to optimize the lithium (Li) storage performance of organic electrodes, which delivers improved specific capacity (763 mAh g−1 at 300 mA g−1), long-term cycling stability (≈90% capacity retention after 600 cycles at 300 mA g−1), and excellent rate performance. The correlation of experimental and computational results confirms that this high Li storage performance derives from the maximum number of active sites (CN sites in the HATN unit and CO sites in the CuO4 unit), favorable electrical conductivity, and efficient mass transfer channels. This strategy of integrating multiple redox-active moieties into the 2D c-MOF opens up a new avenue for the design of high-performance electrode materials. 相似文献
78.
Chuanming Tian Bin Li Yichuan Rui Hao Xiong Yu Zhao Xuefei Han Xinliang Zhou Yu Qiu Wei An Kerui Li Chengyi Hou Yaogang Li Hongzhi Wang Qinghong Zhang 《Advanced functional materials》2023,33(41):2302270
Despite the outstanding power conversion efficiency (PCE) of perovskite solar cells (PSCs) achieved over the years, unsatisfactory stability and lead toxicity remain obstacles that limit their competitiveness and large-scale practical deployment. In this study, in situ polymerizing internal encapsulation (IPIE) is developed as a holistic approach to overcome these challenges. The uniform polymer internal package layer constructed by thermally triggered cross-linkable monomers not only solidifies the ionic perovskite crystalline by strong electron-withdrawing/donating chemical sites, but also acts as a water penetration and ion migration barrier to prolong shelf life under harsh environments. The optimized MAPbI3 and FAPbI3 devices with IPIE treatment yield impressive efficiencies of 22.29% and 24.12%, respectively, accompanied by remarkably enhanced environmental and mechanical stabilities. In addition, toxic water-soluble lead leakage is minimized by the synergetic effect of the physical encapsulation wall and chemical chelation conferred by the IPIE. Hence, this strategy provides a feasible route for preparing efficient, stable, and eco-friendly PSCs. 相似文献
79.
Lin Songyue Hao Xuejiang Liu Yan Yan Dong Liu Jianwei Zhong Mingjun 《Neural computing & applications》2023,35(11):8295-8306
Neural Computing and Applications - Dental X-ray image segmentation is helpful for assisting clinicians to examine tooth conditions and identify dental diseases. Fast and lightweight segmentation... 相似文献
80.
Zhang Man Zhou Yong Liu Bing Zhao Jiaqi Yao Rui Shao Zhiwen Zhu Hancheng Chen Hao 《Pattern Analysis & Applications》2023,26(2):669-677
Pattern Analysis and Applications - The designed method aims to perform image classification tasks efficiently and accurately. Different from the traditional CNN-based image classification methods,... 相似文献