全文获取类型
收费全文 | 44679篇 |
免费 | 5419篇 |
国内免费 | 3968篇 |
专业分类
电工技术 | 4419篇 |
技术理论 | 3篇 |
综合类 | 4436篇 |
化学工业 | 5445篇 |
金属工艺 | 2918篇 |
机械仪表 | 3258篇 |
建筑科学 | 3603篇 |
矿业工程 | 1569篇 |
能源动力 | 1312篇 |
轻工业 | 4137篇 |
水利工程 | 1273篇 |
石油天然气 | 1575篇 |
武器工业 | 664篇 |
无线电 | 5173篇 |
一般工业技术 | 4255篇 |
冶金工业 | 1589篇 |
原子能技术 | 692篇 |
自动化技术 | 7745篇 |
出版年
2024年 | 300篇 |
2023年 | 889篇 |
2022年 | 1750篇 |
2021年 | 2444篇 |
2020年 | 1689篇 |
2019年 | 1221篇 |
2018年 | 1334篇 |
2017年 | 1527篇 |
2016年 | 1357篇 |
2015年 | 1941篇 |
2014年 | 2444篇 |
2013年 | 3008篇 |
2012年 | 3581篇 |
2011年 | 3633篇 |
2010年 | 3408篇 |
2009年 | 3255篇 |
2008年 | 3298篇 |
2007年 | 3395篇 |
2006年 | 2930篇 |
2005年 | 2335篇 |
2004年 | 1843篇 |
2003年 | 1306篇 |
2002年 | 1374篇 |
2001年 | 1241篇 |
2000年 | 887篇 |
1999年 | 461篇 |
1998年 | 185篇 |
1997年 | 207篇 |
1996年 | 155篇 |
1995年 | 125篇 |
1994年 | 88篇 |
1993年 | 79篇 |
1992年 | 74篇 |
1991年 | 53篇 |
1990年 | 58篇 |
1989年 | 26篇 |
1988年 | 28篇 |
1987年 | 15篇 |
1986年 | 21篇 |
1985年 | 9篇 |
1984年 | 7篇 |
1983年 | 8篇 |
1982年 | 12篇 |
1981年 | 5篇 |
1980年 | 10篇 |
1979年 | 9篇 |
1976年 | 8篇 |
1973年 | 4篇 |
1959年 | 8篇 |
1951年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
2.
恶意代码数量已经呈现爆炸式增长,对于恶意代码的检测防护显得尤为重要.近几年,基于深度学习的恶意代码检测方法开始出现,基于此,提出一种新的检测方法,将恶意代码二进制文件转化为十进制数组,并利用一维卷积神经网络(1 Dimention Convolutional Neural Networks,1D CNN)对数组进行分类和识别.针对代码家族之间数量不平衡的现象,该算法选择在分类预测上表现良好的XGBoost,并对Vision Research Lab中的25个不同恶意软件家族的9458个恶意软件样本进行了实验.实验结果表明,所提的方法分类预测精度达到了97%. 相似文献
3.
Dong Liu Xia Ke Zhong-Ce Hu Yu-Guo Zheng 《Journal of Bioscience and Bioengineering》2021,131(5):518-524
4.
Zhenkun Ke Xin Cao Chuanli Shan Lifen Shi Pingping Wang Yong Yang Fengyang Zhao Jiedong Cui Jinwei Li Gang Zhou Min Guan Tao Yu 《Ceramics International》2021,47(14):19605-19613
The purpose of the current work was to research the effect of alkali metal oxide on the structure, thermal properties, viscosity and chemical stability in the glass system (R2O–CaO–B2O3–SiO2) systematically. Because the glass would emulsify when Li2O was added to the glass batch, this article did not discuss Li2O. The results showed that when the amount of Na2O was less than 4 mol.%, there was a higher interconnectivity of borate and silicate sub-networks in glass, as more mixed Si–O–B bonds were present in glass. The glass samples exhibited excellent thermal properties and chemical stabilities. As the amount of Na2O exceeded 4 mol.%, the interconnectivity of borate and silicate sub-networks was weakened. The thermal properties and chemical stabilities of the glass samples were reduced. The connectivity of the silicate sub-network was weakened slightly as the Na/K ratio varied, and the coefficient of thermal expansion (CTE) of the glass samples gradually increased, and the resistance to thermal shock (RTS) value gradually decreased. Moreover, the viscosity of the glass samples decreased with the ratio of Na/Si and Na/K increased. 相似文献
5.
Fangjun Zhu You Shi Guorong Hu Zhongdong Peng Yanbing Cao Qian Sun Zhichen Xue Yinjia Zhang Ke Du 《Ceramics International》2021,47(3):3070-3078
Titanium and boron are simultaneously introduced into LiNi0.8Co0.1Mn0.1O2 to improve the structural stability and electrochemical performance of the material. X-ray diffraction studies reveal that Ti4+ ion replaces Li+ ion and reduces the cation mixing; B3+ ion enters the tetrahedron of the transition metal layers and enlarges the distance of the [LiO6] layers. The co-doped sample has spherical secondary particles with elongated and enlarged primary particles, in which Ti and B elements distribute uniformly. Electrochemical studies reveal the co-doped sample has improved rate performance (183.1 mAh·g-1 at 1 C and 155.5 mAh·g-1 at 10 C) and cycle stability (capacity retention of 94.7% after 100 cycles at 1 C). EIS and CV disclose that Ti and B co-doping reduces charge transfer impedance and suppresses phase change of LiNi0.8Co0.1Mn0.1O2. 相似文献
7.
8.
Rui ZHAO Weikai LI Tian WANG Ke ZHAN Zheng YANG Ya YAN Bin ZHAO Junhe YANG 《材料科学前沿(英文版)》2020,14(2):188
Effective thermal management of electronic integrated devices with high powder density has become a serious issue, which requires materials with high thermal conductivity (TC). In order to solve the problem of weak bonding between graphite and Cu, a novel Cu/graphite film/Cu sandwich composite (Cu/GF/Cu composite) with ultrahigh TC was fabricated by electro-deposition. The micro-riveting structure was introduced to enhance the bonding strength between graphite film and deposited Cu layers by preparing a rectangular array of micro-holes on the graphite film before electro-deposition. TC and mechanical properties of the composites with different graphite volume fractions and current densities were investigated. The results showed that the TC enhancement generated by the micro-riveting structure for Cu/GF/Cu composites at low graphite content was more effective than that at high graphite content, and the strong texture orientation of deposited Cu resulted in high TC. Under the optimizing preparing condition, the highest in-plane TC reached 824.3 W·m−1·K−1, while the ultimate tensile strength of this composite was about four times higher than that of the graphite film. 相似文献
9.
10.
VASP(Vienna Ab-initio Simulation Package)是基于密度泛函理论的通用材料计算模拟软件。随着高性能计算平台的广泛使用和高通量计算的兴起,VASP计算任务的复杂性和数据量也大幅度提升。为了提高材料理论计算的方便程度,减少大量重复的指令和结果检查的复杂性,本文提供了一个基于Python语言的VASP计算辅助程序VaspCZ,能够大幅提高研究者的科研效率。该程序包含软件部分和API部分,软件部分提供了命令行用户界面,基于基本的Linux命令即可一键完成VASP计算的相关操作,为无编程语言基础的研究人员提供了便利。应用程序接口部分服务于具有Python语言基础的研究者,提供了底层库,使得自定义计算(如高通量计算、编写高级应用等)更为简单快捷。本程序包可以显著提高VASP的计算效率,并已经通过Github开源项目公开,提供了详细的使用文档、使用示例和API接口,有望能为广大材料理论研究者提供便利。 相似文献