全文获取类型
收费全文 | 916篇 |
免费 | 46篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 17篇 |
综合类 | 1篇 |
化学工业 | 174篇 |
金属工艺 | 21篇 |
机械仪表 | 26篇 |
建筑科学 | 42篇 |
矿业工程 | 1篇 |
能源动力 | 84篇 |
轻工业 | 69篇 |
水利工程 | 8篇 |
石油天然气 | 6篇 |
无线电 | 107篇 |
一般工业技术 | 185篇 |
冶金工业 | 12篇 |
原子能技术 | 6篇 |
自动化技术 | 207篇 |
出版年
2024年 | 4篇 |
2023年 | 25篇 |
2022年 | 67篇 |
2021年 | 98篇 |
2020年 | 45篇 |
2019年 | 46篇 |
2018年 | 56篇 |
2017年 | 54篇 |
2016年 | 37篇 |
2015年 | 32篇 |
2014年 | 37篇 |
2013年 | 83篇 |
2012年 | 32篇 |
2011年 | 43篇 |
2010年 | 31篇 |
2009年 | 33篇 |
2008年 | 30篇 |
2007年 | 26篇 |
2006年 | 22篇 |
2005年 | 13篇 |
2004年 | 17篇 |
2003年 | 18篇 |
2002年 | 14篇 |
2001年 | 8篇 |
2000年 | 13篇 |
1999年 | 11篇 |
1998年 | 8篇 |
1997年 | 8篇 |
1996年 | 9篇 |
1995年 | 5篇 |
1994年 | 3篇 |
1993年 | 7篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1963年 | 1篇 |
排序方式: 共有966条查询结果,搜索用时 0 毫秒
101.
Gram‐Scale Aqueous Synthesis of Stable Few‐Layered 1T‐MoS2: Applications for Visible‐Light‐Driven Photocatalytic Hydrogen Evolution 下载免费PDF全文
Qin Liu Xiuling Li Qun He Adnan Khalil Daobin Liu Ting Xiang Xiaojun Wu Li Song 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(41):5556-5564
Most recently, much attention has been devoted to 1T phase MoS2 because of its distinctive phase‐engineering nature and promising applications in catalysts, electronics, and energy storage devices. While alkali metal intercalation and exfoliation methods have been well developed to realize unstable 1T‐MoS2, but the aqueous synthesis for producing stable metallic phase remains big challenging. Herein, a new synthetic protocol is developed to mass‐produce colloidal metallic 1T‐MoS2 layers highly stabilized by intercalated ammonium ions (abbreviated as N‐MoS2). In combination with density functional calculations, the X‐ray diffraction pattern and Raman spectra elucidate the excellent stability of metallic phase. As clearly depicted by high‐angle annular dark‐field imaging in an aberration‐corrected scanning transmission electron microscope and extended X‐ray absorption fine structure, the N‐MoS2 exhibits a distorted octahedral structure with a 2a 0 × a 0 basal plane superlattice and 2.72 Å Mo–Mo bond length. In a proof‐of‐concept demonstration for the obtained material's applications, highly efficient photocatalytic activity is achieved by simply hybridizing metallic N‐MoS2 with semiconducting CdS nanorods due to the synergistic effect. As a direct outcome, this CdS:N‐MoS2 hybrid shows giant enhancement of hydrogen evolution rate, which is almost 21‐fold higher than pure CdS and threefold higher than corresponding annealed CdS:2H‐MoS2. 相似文献
102.
Adnan Golubović Ismet Demirdžić Samir Muzaferija 《International journal for numerical methods in engineering》2017,109(11):1607-1620
A numerical procedure for analysis of general laminated plates under transverse load is developed utilizing the Mindlin plate theory, the finite volume discretization, and a segregated solution algorithm. The force and moment balance equations with the laminate constitutive relations are written in the form of a generic transport equation. In order to obtain discrete counterparts of the governing equations, the plate is subdivided into N control volumes by a Cartesian numerical mesh. As a result, five sets of N linear equations with N unknowns are obtained and solved using the conjugate gradient method with preconditioning. For the method validation, a number of test cases are designed to cover thick and thin laminated plates with aspect ratio (width to thickness) from 4 to 100. Simply supported orthotropic, symmetric cross‐ply, and angle‐ply laminated plates under uniform and sinusoidal pressure loads are solved, and results are compared with available analytical solutions. The shear correction factor of 5/6 is utilized throughout the procedure, which is consistent with test cases used in the reviewed literature. Comparisons of the finite volume method results for maximum deflections at the center of the plate and the Navier solutions obtained for aspect ratios 10, 20, and 100 shows a very good agreement. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
103.
Engineering Bimetallic Ag–Cu Nanoalloys for Highly Efficient Oxygen Reduction Catalysts: A Guideline for Designing Ag‐Based Electrocatalysts with Activity Comparable to Pt/C‐20% 下载免费PDF全文
Xiaoqiang Wu Fuyi Chen Nan Zhang Adnan Qaseem Roy L. Johnston 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(19)
Development of highly active and stable Pt‐free oxygen reduction reaction catalysts from earth‐abundant elements remains a grand challenge for highly demanded metal–air batteries. Ag‐based alloys have many advantages over platinum group catalysts due to their low cost, high stability, and acceptable oxygen reduction reaction (ORR) performance in alkaline solutions. Nevertheless, compared to commercial Pt/C‐20%, their catalytic activity still cannot meet the demand of commercialization. In this study, a kind of catalysts screening strategy on Agx Cu100?x nanoalloys is reported, containing the surface modification method, studies of activity enhancement mechanism, and applied research on zinc–air batteries. The results exhibit that the role of selective dealloying (DE) or galvanic displacement (GD) is limited by the “parting limitation”, and this “parting limitation” determines the surface topography, position of d‐band center, and ORR performance of Agx Cu100?x alloys. The GD‐Ag55Cu45 and DE‐Ag25Cu75 catalysts alloys present excellent ORR performance that is comparable to Pt/C‐20%. The relationship between electronic perturbation and specific activity demonstrates that positive shift of the d‐band center (≈0.12 eV, relative to Ag) for GD‐Ag55Cu45 is beneficial for ORR, which is contrary to Pt‐based alloys (negative shift, ≈0.1 eV). Meanwhile, extensive electrochemical and electronic structure characterization indicates that the high work function of GD‐Ag55Cu45 (4.8 eV) is the reason behind their excellent durability for zinc–air batteries. 相似文献
104.
Combined continuum damage‐embedded discontinuity model for explicit dynamic fracture analyses of quasi‐brittle materials 下载免费PDF全文
Timo Saksala Delphine Brancherie Isaac Harari Adnan Ibrahimbegovic 《International journal for numerical methods in engineering》2015,101(3):230-250
In this paper, a novel constitutive model combining continuum damage with embedded discontinuity is developed for explicit dynamic analyses of quasi‐brittle failure phenomena. The model is capable of describing the rate‐dependent behavior in dynamics and the three phases in failure of quasi‐brittle materials. The first phase is always linear elastic, followed by the second phase corresponding to fracture‐process zone creation, represented with rate‐dependent continuum damage with isotropic hardening formulated by utilizing consistency approach. The third and final phase, involving nonlinear softening, is formulated by using an embedded displacement discontinuity model with constant displacement jumps both in normal and tangential directions. The proposed model is capable of describing the rate‐dependent ductile to brittle transition typical of cohesive materials (e.g., rocks and ice). The model is implemented in the finite element setting by using the CST elements. The displacement jump vector is solved for implicitly at the local (finite element) level along with a viscoplastic return mapping algorithm, whereas the global equations of motion are solved with explicit time‐stepping scheme. The model performance is illustrated by several numerical simulations, including both material point and structural tests. The final validation example concerns the dynamic Brazilian disc test on rock material under plane stress assumption. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
105.
Tahir Abbas Khan Sagheer Abbas Allah Ditta Muhammad Adnan Khan Hani Alquhayz Areej Fatima Muhammad Farhan Khan 《计算机、材料和连续体(英文)》2020,65(3):2591-2605
The prediction of human diseases, particularly COVID-19, is an extremely
challenging task not only for medical experts but also for the technologists supporting
them in diagnosis and treatment. To deal with the prediction and diagnosis of COVID-19,
we propose an Internet of Medical Things-based Smart Monitoring Hierarchical
Mamdani Fuzzy Inference System (IoMTSM-HMFIS). The proposed system determines
the various factors like fever, cough, complete blood count, respiratory rate, Ct-chest,
Erythrocyte sedimentation rate and C-reactive protein, family history, and antibody
detection (lgG) that are directly involved in COVID-19. The expert system has two input
variables in layer 1, and seven input variables in layer 2. In layer 1, the initial
identification for COVID-19 is considered, whereas in layer 2, the different factors
involved are studied. Finally, advanced lab tests are conducted to identify the actual
current status of the disease. The major focus of this study is to build an IoMT-based
smart monitoring system that can be used by anyone exposed to COVID-19; the system
would evaluate the user’s health condition and inform them if they need consultation with
a specialist for quarantining. MATLAB-2019a tool is used to conduct the simulation. The
COVID-19 IoMTSM-HMFIS system has an overall accuracy of approximately 83%.
Finally, to achieve improved performance, the analysis results of the system were shared
with experts of the Lahore General Hospital, Lahore, Pakistan. 相似文献
106.
Nadia Tabassum Allah Ditta Tahir Alyas Sagheer Abbas Hani Alquhayz Natash Ali Mian Muhammad Adnan Khan 《计算机、材料和连续体(英文)》2021,67(3):3129-3141
Cloud computing is becoming popular technology due to its functional properties and variety of customer-oriented services over the Internet. The design of reliable and high-quality cloud applications requires a strong Quality of Service QoS parameter metric. In a hyperconverged cloud ecosystem environment, building high-reliability cloud applications is a challenging job. The selection of cloud services is based on the QoS parameters that play essential roles in optimizing and improving cloud rankings. The emergence of cloud computing is significantly reshaping the digital ecosystem, and the numerous services offered by cloud service providers are playing a vital role in this transformation. Hyperconverged software-based unified utilities combine storage virtualization, compute virtualization, and network virtualization. The availability of the latter has also raised the demand for QoS. Due to the diversity of services, the respective quality parameters are also in abundance and need a carefully designed mechanism to compare and identify the critical, common, and impactful parameters. It is also necessary to reconsider the market needs in terms of service requirements and the QoS provided by various CSPs. This research provides a machine learning-based mechanism to monitor the QoS in a hyperconverged environment with three core service parameters: service quality, downtime of servers, and outage of cloud services. 相似文献
107.
The adsorption of Acid Red 57 (AR57) onto calcined-alunite was examined in aqueous solution in a batch system with respect to contact time, pH and temperature. The first-order, pseudo-second-order kinetic and the intraparticle diffusion models were used to describe the kinetic data and the rate constants were evaluated. The experimental data fitted very well the pseudo-second-order kinetic model and also followed the intraparticle diffusion model up to 90 min. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms and the isotherm constants were also determined. The equilibrium data are successfully fitted to the Langmuir adsorption isotherm. The Langmuir isotherm constant, K(L), was used to evaluate the changes of free energy, enthalpy and entropy of adsorption for the adsorption of AR57 onto calcined-alunite. The results indicate that calcined-alunite could be employed as low-cost material for the removal of acid dyes from textile effluents. 相似文献
108.
109.
Adnan Bibic Linda Knutsson Freddy Ståhlberg Ronnie Wirestam 《Magma (New York, N.Y.)》2010,23(3):125-137
Purpose
To investigate a wavelet-based filtering scheme for denoising of arterial spin labeling (ASL) data, potentially enabling reduction of the required number of averages and the acquisition time. 相似文献110.