全文获取类型
收费全文 | 3451篇 |
免费 | 200篇 |
国内免费 | 16篇 |
专业分类
电工技术 | 131篇 |
综合类 | 31篇 |
化学工业 | 734篇 |
金属工艺 | 91篇 |
机械仪表 | 90篇 |
建筑科学 | 96篇 |
矿业工程 | 22篇 |
能源动力 | 125篇 |
轻工业 | 433篇 |
水利工程 | 34篇 |
石油天然气 | 23篇 |
武器工业 | 1篇 |
无线电 | 346篇 |
一般工业技术 | 607篇 |
冶金工业 | 241篇 |
原子能技术 | 56篇 |
自动化技术 | 606篇 |
出版年
2023年 | 26篇 |
2022年 | 55篇 |
2021年 | 90篇 |
2020年 | 85篇 |
2019年 | 80篇 |
2018年 | 121篇 |
2017年 | 121篇 |
2016年 | 138篇 |
2015年 | 99篇 |
2014年 | 158篇 |
2013年 | 280篇 |
2012年 | 246篇 |
2011年 | 314篇 |
2010年 | 177篇 |
2009年 | 186篇 |
2008年 | 117篇 |
2007年 | 127篇 |
2006年 | 75篇 |
2005年 | 145篇 |
2004年 | 71篇 |
2003年 | 82篇 |
2002年 | 98篇 |
2001年 | 82篇 |
2000年 | 35篇 |
1999年 | 43篇 |
1998年 | 91篇 |
1997年 | 70篇 |
1996年 | 45篇 |
1995年 | 35篇 |
1994年 | 30篇 |
1993年 | 21篇 |
1992年 | 18篇 |
1991年 | 19篇 |
1990年 | 20篇 |
1989年 | 15篇 |
1988年 | 13篇 |
1987年 | 10篇 |
1986年 | 17篇 |
1985年 | 14篇 |
1984年 | 23篇 |
1983年 | 14篇 |
1982年 | 9篇 |
1981年 | 10篇 |
1980年 | 14篇 |
1979年 | 17篇 |
1978年 | 13篇 |
1977年 | 11篇 |
1976年 | 14篇 |
1974年 | 11篇 |
1973年 | 14篇 |
排序方式: 共有3667条查询结果,搜索用时 15 毫秒
1.
2.
Aleksandar Miletić Peter Panjan Miha Čekada Lazar Kovačević Pal Terek Janez Kovač Goran Dražič Branko Škorić 《Ceramics International》2021,47(2):2022-2033
With the goal to produce a hard and tough coating intended for tribological applications, CrAlN/TiSiN nanolayer coating was prepared by alternative deposition of CrAlN and TiSiN layers. In the first part of the article, a detailed study of phase composition, microstructure, and layer structure of CrAlN/TiSiN coating is presented. In the second part, its mechanical properties, fracture and tribological behavior are compared to the nanocomposite TiSiN coating. An industrial magnetron sputtering unit was used for coating deposition. X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy were used for compositional and microstructural analysis. Mechanical properties and fracture behavior were studied by instrumented indentation and focused ion beam techniques. Tribological properties were evaluated by ball-on-disk test in a linear reciprocal mode. A complex layer structure was found in the nanolayer coating. The TiSiN layers were epitaxially stabilized inside the coating which led to formation of dislocations at interfaces, to introduction of disturbances in the coating growth, and as a result, to development of fine-grained columnar microstructure. Indentation load required for the onset of fracture was twice lower for the nanolayer CrAlN/TiSiN, compared to the nanocomposite TiSiN coating. This agrees very well with their mechanical properties, with H3/E2 being twice higher for the TiSiN coating. However, the nanolayer coating experienced less severe damage, which had a strong impact on tribological behavior. A magnitude of order lower wear rate and four times lower steady state friction coefficient were found for the nanolayer coating. 相似文献
3.
4.
Vu Hoa T. Nguyen Manh B. Vu Tan M. Le Giang H. Pham Trang T. T. Nguyen Trinh Duy Vu Tuan A. 《Topics in Catalysis》2020,63(11-14):1046-1055
Topics in Catalysis - Nano Fe-BTC/graphene oxide (GO) composites were successfully synthesized by hydrothermal treatment with a microwave-assisted method. Samples were characterized by X-ray... 相似文献
5.
6.
Effect of Supports and Promoters on the Performance of Ni-Based Catalysts in Ethanol Steam Reforming
Thanh Khoa Phung Thong Le Minh Pham Anh-Nga T. Nguyen Khanh B. Vu Ha Ngoc Giang Tuan-Anh Nguyen Thanh Cong Huynh Hong Duc Pham 《化学工程与技术》2020,43(4):672-688
Ethanol steam reforming (ESR) is one of the potential processes to convert ethanol into valuable products. Hydrogen produced from ESR is considered as green energy for the future and can be an excellent alternative to fossil fuels with the aim of mitigating the greenhouse gas effect. The ESR process has been well studied, using transition metals as catalysts coupled with both acidic and basic oxides as supports. Among various reported transition metals, Ni is an inexpensive material with activity comparable to that of noble metals, showing promising ethanol conversion and hydrogen yields. Additionally, different promoters and supports were utilized to enhance the hydrogen yield and the catalyst stability. This review summarizes and discusses the influences of the supports and promoters of Ni-based catalysts on the ESR process. 相似文献
7.
Alfredo M. Gravagnuolo Eden Morales‐Narváez Charlene Regina Santos Matos Sara Longobardi Paola Giardina Arben Merkoçi 《Advanced functional materials》2015,25(38):6084-6092
Class I hydrophobin Vmh2, a peculiar surface active and versatile fungal protein, is known to self‐assemble into chemically stable amphiphilic films, to be able to change wettability of surfaces, and to strongly adsorb other proteins. Herein, a fast, highly homogeneous and efficient glass functionalization by spontaneous self‐assembling of Vmh2 at liquid–solid interfaces is achieved (in 2 min). The Vmh2‐coated glass slides are proven to immobilize not only proteins but also nanomaterials such as graphene oxide (GO) and quantum dots (QDs). As models, bovine serum albumin labeled with Alexa 555 fluorophore, anti‐immunoglobulin G antibodies, and cadmium telluride QDs are patterned in a microarray fashion in order to demonstrate functionality, reproducibility, and versatility of the proposed substrate. Additionally, a GO layer is effectively and homogeneously self‐assembled onto the studied functionalized surface. This approach offers a quick and simple alternative to immobilize nanomaterials and proteins, which is appealing for new bioanalytical and nanobioenabled applications. 相似文献
8.
L. Vu‐Quoc V. Srinivas Y. Zhai 《International journal for numerical methods in engineering》2003,58(3):397-461
We establish a systematic methodology to design and analyse electromagnetic components such as advanced multilayer ceramic capacitors (MLCCs) using the finite element (FE) method. We employ a coupled formulation to compute the interaction between the electric and magnetic fields. Unlike a linear distribution of current assumed in the circuit model, an accurate electrostatic solution to model the entire advanced MLCCs (4 × 4 × 27 = 432 cells) is presented. The FE solution is used to compute the lumped parameters for a range of frequencies. These lumped parameters are then used to compute the parasitic elements of the MLCCs. We introduce two algorithms to efficiently analyse the behaviour of a capacitor with changing frequency. The lower frequency (much below the self‐resonant frequency of the capacitor) algorithm separates the effect of the electric and magnetic fields and reduces the computational effort required to solve the FE problem, whereas, the high‐frequency algorithm couples the effect between the electric and the magnetic fields. We use these algorithms in conjunction with a new multiple scale technique to effectively determine the small values of R, L and C in MLCCs. The formulation, the implementation, and the numerical results demonstrate the efficacy of the present FE formulation and establish a systematic methodology to design and analyse advanced electromagnetic components. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
9.
10.
Ohne Zusammenfassung 相似文献