全文获取类型
收费全文 | 33397篇 |
免费 | 3832篇 |
国内免费 | 2397篇 |
专业分类
电工技术 | 2963篇 |
技术理论 | 4篇 |
综合类 | 2916篇 |
化学工业 | 4857篇 |
金属工艺 | 2062篇 |
机械仪表 | 2139篇 |
建筑科学 | 2792篇 |
矿业工程 | 837篇 |
能源动力 | 993篇 |
轻工业 | 2794篇 |
水利工程 | 704篇 |
石油天然气 | 1558篇 |
武器工业 | 380篇 |
无线电 | 3802篇 |
一般工业技术 | 3700篇 |
冶金工业 | 1282篇 |
原子能技术 | 438篇 |
自动化技术 | 5405篇 |
出版年
2024年 | 165篇 |
2023年 | 680篇 |
2022年 | 1228篇 |
2021年 | 1856篇 |
2020年 | 1312篇 |
2019年 | 972篇 |
2018年 | 1080篇 |
2017年 | 1215篇 |
2016年 | 1093篇 |
2015年 | 1515篇 |
2014年 | 1820篇 |
2013年 | 2307篇 |
2012年 | 2551篇 |
2011年 | 2576篇 |
2010年 | 2307篇 |
2009年 | 2127篇 |
2008年 | 2098篇 |
2007年 | 1992篇 |
2006年 | 1810篇 |
2005年 | 1531篇 |
2004年 | 1104篇 |
2003年 | 1018篇 |
2002年 | 1148篇 |
2001年 | 1019篇 |
2000年 | 718篇 |
1999年 | 551篇 |
1998年 | 324篇 |
1997年 | 331篇 |
1996年 | 268篇 |
1995年 | 206篇 |
1994年 | 157篇 |
1993年 | 113篇 |
1992年 | 95篇 |
1991年 | 63篇 |
1990年 | 69篇 |
1989年 | 41篇 |
1988年 | 39篇 |
1987年 | 23篇 |
1986年 | 24篇 |
1985年 | 7篇 |
1984年 | 6篇 |
1982年 | 11篇 |
1981年 | 6篇 |
1980年 | 5篇 |
1979年 | 7篇 |
1978年 | 4篇 |
1977年 | 4篇 |
1976年 | 9篇 |
1973年 | 4篇 |
1951年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
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
2.
Dong Liu Xia Ke Zhong-Ce Hu Yu-Guo Zheng 《Journal of Bioscience and Bioengineering》2021,131(5):518-524
3.
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
4.
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
5.
针对传统PET材料不具备抗菌、不耐洗等问题,以煎煮法为基础,以草珊瑚、艾叶和薄荷为原料,制备含植物活性成分的溶液,其具有抗菌、杀菌的作用;以溶胶-凝胶法为多孔材料制备方法,用十六烷基三甲基溴化铵、十二烷基苯磺酸钠表面活性剂为模板剂,正硅酸乙酯为有机硅源,氨水为催化剂,乙醇和乙醚为助溶剂,在水-乙醇-乙醚体系中合成多孔二氧化硅微球;然后,多孔二氧化硅微球与提取液混合制备含植物活性成分的多孔二氧化硅分子巢;最后以制备的多孔二氧化硅分子巢与普通的聚酯切片用熔融纺丝工艺进行造粒、纺丝,得到具有抗菌、杀菌和耐洗的多功能涤纶纤维.通过SEM微观观察和力学性能测试、抗菌试验、耐洗性测试,对上述制备的多功能涤纶纤维性能进行验证.结果表明:在模板剂总浓度为0.029 mol·L-1、V醇:V醚=20:20、两种表面活性剂比为4:1时,得到的多孔SiO2微球排列规整;当多孔二氧化硅分子巢掺量(质量分数)在0.5%~1%时,通过熔融共混纺丝得到的新型多功能涤纶纤维力学性能表现最优;当多孔二氧化硅分子巢掺量(质量分数)在1%时,得到的新型多功能涤纶纤维的抗菌性能达到87.9%.而二氧化硅分子巢掺量越高,纤维材料越耐洗.以上结果说明本试验制备涤纶纤维的方案可行. 相似文献
6.
At present, the development and implementation of digital transformation are the keys to promoting high-quality industry development. The new digital fabrication method of robotic 3D printing is a research area being studied by many to tackle the issue of the declining productivity of traditional construction methods. Although many studies have been done, most of the current 3D printing projects are facing limitations in terms of scale. In order to bridge the gap, this article proposed a mass customization 3D printing framework system for large-scale projects. This article discusses how mass customization is made possible through the joint operation of the FUROBOT software and 3D printing hardware. By taking the east gate of Nanjing Happy Valley Plaza as a case study, the article demonstrates and studies the feasibility of the large-scale mass customization 3D printing framework system. 相似文献
7.
9.
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