全文获取类型
收费全文 | 97187篇 |
免费 | 10056篇 |
国内免费 | 6768篇 |
专业分类
电工技术 | 7777篇 |
技术理论 | 4篇 |
综合类 | 9310篇 |
化学工业 | 13036篇 |
金属工艺 | 6351篇 |
机械仪表 | 6499篇 |
建筑科学 | 7364篇 |
矿业工程 | 3526篇 |
能源动力 | 2609篇 |
轻工业 | 11567篇 |
水利工程 | 2734篇 |
石油天然气 | 4060篇 |
武器工业 | 1359篇 |
无线电 | 10367篇 |
一般工业技术 | 8852篇 |
冶金工业 | 3804篇 |
原子能技术 | 1235篇 |
自动化技术 | 13557篇 |
出版年
2024年 | 550篇 |
2023年 | 1627篇 |
2022年 | 3624篇 |
2021年 | 4535篇 |
2020年 | 3401篇 |
2019年 | 2482篇 |
2018年 | 2853篇 |
2017年 | 3177篇 |
2016年 | 2897篇 |
2015年 | 4473篇 |
2014年 | 5513篇 |
2013年 | 6397篇 |
2012年 | 7865篇 |
2011年 | 8405篇 |
2010年 | 7779篇 |
2009年 | 7312篇 |
2008年 | 7401篇 |
2007年 | 6916篇 |
2006年 | 6029篇 |
2005年 | 4761篇 |
2004年 | 3528篇 |
2003年 | 2696篇 |
2002年 | 2596篇 |
2001年 | 2143篇 |
2000年 | 1618篇 |
1999年 | 943篇 |
1998年 | 511篇 |
1997年 | 419篇 |
1996年 | 333篇 |
1995年 | 283篇 |
1994年 | 197篇 |
1993年 | 159篇 |
1992年 | 109篇 |
1991年 | 114篇 |
1990年 | 87篇 |
1989年 | 59篇 |
1988年 | 34篇 |
1987年 | 26篇 |
1986年 | 28篇 |
1985年 | 10篇 |
1984年 | 10篇 |
1983年 | 9篇 |
1982年 | 4篇 |
1981年 | 16篇 |
1980年 | 33篇 |
1979年 | 10篇 |
1976年 | 5篇 |
1973年 | 3篇 |
1959年 | 14篇 |
1951年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Wen-Ke Wang Hui Zhang Hyungjun Park Jun-Hai Yong Jean-Claude Paul Jia-Guang Sun 《Computer aided design》2008,40(10-11):999-1008
A new algorithm for reducing control points in lofted surface interpolation to rows of data points is presented in this paper. The key step of surface lofting is to obtain a set of compatible B-spline curves interpolating each row. Given a set of points and their parameterization, a necessary and sufficient condition is proposed to determine the existence of interpolating B-spline curves defined on a given knot vector. Based on this condition, we first properly construct a common knot vector that guarantees the existence of interpolating B-spline curves to each row of points. Then we calculate a set of interpolating B-spline curves defined on the common knot vector by energy minimization. Using this method, fewer control points are employed while maintaining a visually pleasing shape of the lofted surface. Several experimental results demonstrate the usability and quality of the proposed method. 相似文献
72.
73.
Layered image coding using the DCT pyramid 总被引:2,自引:0,他引:2
A block-based subband image coder that exploits the ability to perform decimation in the discrete cosine transform (DCT) domain to effect a pyramidal data structure is described. The proposed "DCT pyramid" has a distinct feature of improved image rendition properties without the associated blocking artifacts at low bit-rates. 相似文献
74.
75.
Hui Zhang Yinkun Sun Junjie Yang Zhiyu Sun Yanxin Zhao Xin Li Wei Wang Dongwei Lu Jun Ma 《Advanced functional materials》2023,33(40):2302816
Precise adjustment of the pore size, damage repair, and efficient cleaning is all challenges for the wider application of inorganic membranes. This study reports a simple strategy of combining dry-wet spinning and electrosynthesis to fabricate stainless-steel metal–organic framework composite membranes characterized by customizable pore sizes, targeted reparability, and high catalytic activity for membrane cleaning. The membrane pore size can be precisely customized in the range of 14–212 nm at nanoscale, and damaged membranes can be repaired by targeted treatment in 120 s. In addition, advanced oxidation processes can be used to quickly clean the membrane and achieve 98% flux recovery. The synergistic actions of the membrane matrix and the selective layer increase the adsorption energy of active sites to oxidant, shorten the electron transfer cycle, and enhance the overall catalytic performance. This study can provide a new direction for the development of advanced membranes for water purification and high-efficiency membrane cleaning methods. 相似文献
76.
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
77.
Computational Visual Media - In this paper, we tackle the challenging problem of point cloud completion from the perspective of feature learning. Our key observation is that to recover the... 相似文献
78.
Wireless Personal Communications - Recently, Lee et al. (Sensors 20(14): 3983, 2020) proposed a certificateless aggregate arbitrated signature scheme CLAAS for IoT environments. Addobea et... 相似文献
80.