全文获取类型
收费全文 | 4492篇 |
免费 | 383篇 |
国内免费 | 195篇 |
专业分类
电工技术 | 224篇 |
技术理论 | 3篇 |
综合类 | 354篇 |
化学工业 | 805篇 |
金属工艺 | 172篇 |
机械仪表 | 230篇 |
建筑科学 | 407篇 |
矿业工程 | 107篇 |
能源动力 | 74篇 |
轻工业 | 350篇 |
水利工程 | 84篇 |
石油天然气 | 228篇 |
武器工业 | 25篇 |
无线电 | 543篇 |
一般工业技术 | 483篇 |
冶金工业 | 200篇 |
原子能技术 | 83篇 |
自动化技术 | 698篇 |
出版年
2024年 | 6篇 |
2023年 | 56篇 |
2022年 | 116篇 |
2021年 | 125篇 |
2020年 | 119篇 |
2019年 | 88篇 |
2018年 | 116篇 |
2017年 | 150篇 |
2016年 | 142篇 |
2015年 | 167篇 |
2014年 | 188篇 |
2013年 | 273篇 |
2012年 | 291篇 |
2011年 | 325篇 |
2010年 | 280篇 |
2009年 | 265篇 |
2008年 | 267篇 |
2007年 | 258篇 |
2006年 | 286篇 |
2005年 | 245篇 |
2004年 | 152篇 |
2003年 | 136篇 |
2002年 | 134篇 |
2001年 | 93篇 |
2000年 | 111篇 |
1999年 | 129篇 |
1998年 | 103篇 |
1997年 | 85篇 |
1996年 | 71篇 |
1995年 | 42篇 |
1994年 | 55篇 |
1993年 | 37篇 |
1992年 | 22篇 |
1991年 | 27篇 |
1990年 | 17篇 |
1989年 | 20篇 |
1988年 | 21篇 |
1987年 | 11篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1984年 | 7篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 5篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有5070条查询结果,搜索用时 15 毫秒
101.
102.
Yueteng Gao Wei Li Boning Ou Shuhua Zhang Huwei Wang Junyang Hu Feiyu Kang Dengyun Zhai 《Advanced functional materials》2023,33(47):2305829
Potassium ion batteries using graphite anode and high-voltage cathodes are considered to be optimizing candidates for large-scale energy storage. However, the lack of suitable electrolytes significantly hinders the development of high-voltage potassium ion batteries. Herein, a dilute (0.8 m ) fluorinated phosphate electrolyte is proposed, which exhibits extraordinary compatibility with both graphite anode and high-voltage cathodes. The phosphate solvent, tris(2,2,2-trifluoroethyl) phosphate (TFP), has weak solvating ability, which not only allows the formation of robust anion-derived solid electrolyte interphase on graphite anode but also effectively suppresses the corrosion of Al current collector at high voltage. Meanwhile, the high oxidative stability of fluorinated TFP solvent enables stable ultrahigh-voltage (4.95 V) cycling of a potassium vanadium fluorophosphate (KVPO4F) cathode. Using TFP-based electrolyte, the 4.9 V-class potassium ion full cell based on graphite anode and KVPO4F cathode shows rather remarkable cycling performance with a high capacity retention of 87.2% after 200 cycles. This study provides a route to develop dilute electrolytes for high-voltage potassium ion batteries, by utilizing solvents with both weak solvating ability and high oxidative stability. 相似文献
103.
Kong Chao Ou Weihua Gong Xiaofeng Li Weian Han Jie Yao Yi Xiong Jiahao 《中国邮电高校学报(英文版)》2022,29(6):73-82
Face anti-spoofing is used to assist face recognition system to judge whether the detected face is real face or fake face. In the traditional face anti-spoofing methods, features extracted by hand are used to describe the difference between living face and fraudulent face. But these handmade features do not apply to different variations in an unconstrained environment. The convolutional neural network (CNN) for face deceptions achieves considerable results. However, most existing neural network-based methods simply use neural networks to extract single-scale features from single-modal data, while ignoring multi-scale and multi-modal information. To address this problem, a novel face anti-spoofing method based on multi-modal and multi-scale features fusion ( MMFF) is proposed. Specifically, first residual network ( Resnet )-34 is adopted to extract features of different scales from each modality, then these features of different scales are fused by feature pyramid network (FPN), finally squeeze-and-excitation fusion ( SEF) module and self-attention network ( SAN) are combined to fuse features from different modalities for classification. Experiments on the CASIA-SURF dataset show that the new method based on MMFF achieves better performance compared with most existing methods. 相似文献
104.
Recent advances in the research on the molecular mechanism of cell death and methods for preparation of nanomaterials make the integration of various therapeutic approaches,targeting,and imaging modes into a single nanoscale complex a new trend for the development of future nanotherapeutics.Hence,a novel ellipsoidal composite nanoplatform composed of a magnetic Fe3O4/Fe nanorod core (~120 nm) enwrapped by a catalase (CAT)-imprinted fibrous SiO2/ polydopamine (F-SiO2/PDA) shell with thickness 70 nm was prepared in this work.In vitro experiments showed that the Fe3O4/Fe@F-SiO2/PDA nanoparticles can selectively inhibit the bioactivity of CAT in tumor cells by the molecular imprinting technique.As a result,the H2O2 level in tumor cells was elevated dramatically.At the same time,the Fe3O4/Fe core released Fe ions to catalyze the conversion of H2O2 to ·OH in tumor cells.Eventually,the concentration of ·OH in tumor cells rapidly rose to a lethal level thus triggering apoptosis.Combined with the remarkable near-infrared light (NIR) photothermal effect of the CATimprinted PDA layer,the Fe3O4/Fe@F-SiO2/PDA nanoparticles can effectively kill MCF-7,HeLa,and 293T tumor cells but are not toxic to nontumor cells.Furthermore,these nanoparticles show good capacity for magnetic targeting and suitability for magnetic resonance imaging (MRI).Therefore,the integrated multifunctional nanoplatform opens up new possibilities for high-efficiency visual targeted nonchemo therapy for cancer. 相似文献
105.
Tomohiro Tabata Ou Zhang Yuna Yamanaka Peii Tsai 《Clean Technologies and Environmental Policy》2016,18(6):1735-1744
The paper discusses development of a method for estimating disaster waste that can be potentially generated by a natural disaster in the future for pre-disaster waste management. In particular, this research focuses on micro-disaster waste originating from household consumer durables. We documented the number of household consumer durables and built a mass per unit database of major consumer durables using web-based and statistical surveys. We also estimated present and future figures of disaster waste that can be generated in the study area. The estimated total amount of disaster waste that could be generated in 2015 was 24.1 kt (18.1–29.8 kt) and 108 kt (81.8–133 kt) for Kobe City and Ise-Shima region, respectively. The total quantities of TV sets, air conditioners, refrigerators, and washing machines generated in Kobe and Ise-Shima will range between 10.9 and 22.8 kt (247,000–545,000 units) in 2015, and 10.7 kt to 22.8 kt (249,000–550,000 units) in 2035. The quantity estimated for 2015 is equal to 61 % of the annual processing capacity of Plant A, Japan’s leading home appliances recycling plant. Finally, we discussed the contribution of the estimation results and geographic information systems in future recycling planning. 相似文献
106.
Qi Jia Xin Ou Manuel Langer Benjamin Schreiber Jörg Grenzer Pablo F. Siles Raul D. Rodriguez Kai Huang Ye Yuan Alireza Heidarian René Hübner Tiangui You Wenjie Yu Kilian Lenz Jürgen Lindner Xi Wang Stefan Facsko 《Nano Research》2018,11(7):3519-3528
A nanofabrication method for the production of ultra-dense planar metallic nanowire arrays scalable to wafer-size is presented. The method is based on an efficient template deposition process to grow diverse metallic nanowire arrays with extreme regularity in only two steps. First, III–V semiconductor substrates are irradiated by a low-energy ion beam at an elevated temperature, forming a highly ordered nanogroove pattern by a “reverse epitaxy” process due to self-assembly of surface vacancies. Second, diverse metallic nanowire arrays (Au, Fe, Ni, Co, FeAl alloy) are fabricated on these III–V templates by deposition at a glancing incidence angle. This method allows for the fabrication of metallic nanowire arrays with periodicities down to 45 nm scaled up to wafer-size fabrication. As typical noble and magnetic metals, the Au and Fe nanowire arrays produced here exhibited large anisotropic optical and magnetic properties, respectively. The excitation of localized surface plasmon resonances (LSPRs) of the Au nanowire arrays resulted in a high electric field enhancement, which was used to detect phthalocyanine (CoPc) in surface-enhanced Raman scattering (SERS). Furthermore, the Fe nanowire arrays showed a very high in-plane magnetic anisotropy of approximately 412 mT, which may be the largest in-plane magnetic anisotropy field yet reported that is solely induced via shape anisotropy within the plane of a thin film. 相似文献
107.
L Tonella BJ Walsh JC Sanchez K Ou MR Wilkins M Tyler S Frutiger AA Gooley I Pescaru RD Appel JX Yan A Bairoch C Hoogland FS Morch GJ Hughes KL Williams DF Hochstrasser 《Canadian Metallurgical Quarterly》1998,19(11):1960-1971
The combination of two-dimensional polyacrylamide gel electrophoresis (2-D PAGE), computer image analysis and several protein identification techniques allowed the Escherichia coli SWISS-2DPAGE database to be established. This is part of the ExPASy molecular biology server accessible through the WWW at the URL address http://www.expasy.ch/ch2d/ch2d-top.html . Here we report recent progress in the development of the E. coli SWISS-2DPAGE database. Proteins were separated with immobilized pH gradients in the first dimension and sodium dodecyl sulfate-polyacrylamide gel electrophoresis in the second dimension. To increase the resolution of the separation and thus the number of identified proteins, a variety of wide and narrow range immobilized pH gradients were used in the first dimension. Micropreparative gels were electroblotted onto polyvinylidene difluoride membranes and spots were visualized by amido black staining. Protein identification techniques such as amino acid composition analysis, gel comparison and microsequencing were used, as well as a recently described Edman "sequence tag" approach. Some of the above identification techniques were coupled with database searching tools. Currently 231 polypeptides are identified on the E. coli SWISS-2DPAGE map: 64 have been identified by N-terminal microsequencing, 39 by amino acid composition, and 82 by sequence tag. Of 153 proteins putatively identified by gel comparison, 65 have been confirmed. Many proteins have been identified using more than one technique. Faster progress in the E. coli proteome project will now be possible with advances in biochemical methodology and with the completion of the entire E. coli genome. 相似文献
108.
109.
In this paper, three direct search algorithms, i.e. a modified simplex, random direction search and enhanced Powell’s methods
together with a new localised response surface method are presented and applied to solve die shape optimisation problems for
achieving net-shape accuracy in metal forming processes. The main motivation is to develop efficient and easy to implement
optimisation algorithms in metal forming simulations which often involve complex tool and workpiece interaction and coupled
thermal and mechanical analysis. Three case studies are presented including a simple upsetting, a 2D blade forging and a forward
extrusion problem. In all cases, the objective was to achieve net-shape accuracy of the formed parts, one important criterion
for precision forming. C+ + programs were developed to implement these algorithms and to automatically integrate optimisation
computation and forging simulation. The optimisation results from the three case problems show that direct search based methods
especially the modified simplex and the localised response surface methods are computationally efficient and robust for net-shape
forging and extrusion optimisation problems. It is also suggested that these methods can be used in more complex forging problems
where die shape design and optimisation are essential for achieving net-shape accuracy. 相似文献
110.