全文获取类型
收费全文 | 1923篇 |
免费 | 108篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 31篇 |
综合类 | 1篇 |
化学工业 | 479篇 |
金属工艺 | 32篇 |
机械仪表 | 44篇 |
建筑科学 | 46篇 |
矿业工程 | 5篇 |
能源动力 | 54篇 |
轻工业 | 263篇 |
水利工程 | 21篇 |
石油天然气 | 9篇 |
无线电 | 173篇 |
一般工业技术 | 285篇 |
冶金工业 | 181篇 |
原子能技术 | 6篇 |
自动化技术 | 403篇 |
出版年
2023年 | 13篇 |
2022年 | 49篇 |
2021年 | 74篇 |
2020年 | 43篇 |
2019年 | 54篇 |
2018年 | 60篇 |
2017年 | 52篇 |
2016年 | 54篇 |
2015年 | 64篇 |
2014年 | 69篇 |
2013年 | 134篇 |
2012年 | 119篇 |
2011年 | 138篇 |
2010年 | 114篇 |
2009年 | 101篇 |
2008年 | 107篇 |
2007年 | 80篇 |
2006年 | 73篇 |
2005年 | 68篇 |
2004年 | 57篇 |
2003年 | 44篇 |
2002年 | 41篇 |
2001年 | 33篇 |
2000年 | 17篇 |
1999年 | 28篇 |
1998年 | 49篇 |
1997年 | 27篇 |
1996年 | 25篇 |
1995年 | 26篇 |
1994年 | 10篇 |
1993年 | 25篇 |
1992年 | 10篇 |
1991年 | 5篇 |
1990年 | 8篇 |
1989年 | 9篇 |
1988年 | 9篇 |
1987年 | 5篇 |
1985年 | 8篇 |
1984年 | 11篇 |
1983年 | 9篇 |
1982年 | 10篇 |
1981年 | 15篇 |
1980年 | 6篇 |
1979年 | 5篇 |
1978年 | 7篇 |
1976年 | 7篇 |
1971年 | 6篇 |
1970年 | 4篇 |
1966年 | 4篇 |
1936年 | 4篇 |
排序方式: 共有2033条查询结果,搜索用时 515 毫秒
61.
Caleb A. Ellefson Oscar Marin-Flores Su Ha M. Grant Norton 《Journal of Materials Science》2012,47(5):2057-2071
Molybdenum dioxide (MoO2) is a transition metal oxide with unusual metal-like electrical conductivity and high catalytic activity toward reforming
hydrocarbons. This review covers the synthesis techniques used to fabricate MoO2 in a variety of morphologies and particle sizes. Processing from molybdenum ore and reduction from MoO3 are also covered, with emphasis on reduction mechanisms and kinetic considerations. Discussions of various solution-based
and gas phase synthesis techniques shed light on strategies to achieve various unique morphologies, which leads into a brief
discussion of nanoscale MoO2. Nanoscale MoO2 is of interest for important technological applications including catalysts for partial oxidation of hydrocarbons, solid
oxide fuel cell anodes, and high-capacity reversible lithium ion battery anodes. 相似文献
62.
This review discusses the latest developments in ligand design for the Pd-catalyzed asymmetric intermolecular Mizoroki-Heck reaction, from the successful phosphine/phosphinite-nitrogen ligands to the recently reported phosphite-nitrogen ligands. The presence of a biaryl phosphite group offers several advantages as a ligand scaffold for this process. 相似文献
63.
Maissa Farhat Oscar Barambones Lassâad Sbita 《International Journal of Adaptive Control and Signal Processing》2017,31(11):1655-1665
In this paper, a photovoltaic system topology incorporating a new maximum power point tracking (MPPT) controller method is presented. This method uses an autotuning estimator and a PI controller to make the system work in the maximum power point. The controller is formulated based on the bijectivity in the photovoltaic generator characteristic; therefore, if the optimal voltage is reached, this means that the maximum of power is obtained. The proposed MPPT algorithm is implemented on a dSpace DS1104 controller board. In order to demonstrate the efficiency of the proposed algorithm in real time, an experimental setup using a boost converter connected to a resistive load is successfully implemented and studied. The obtained experimental results prove the validity of the proposed MPPT algorithm. 相似文献
64.
Rhian Stotts Oscar G. Lopez-Jaramillo Scott Kelley Aimee Krafft Michael Kuby 《International Journal of Hydrogen Energy》2021,46(12):8736-8748
This article develops and tests an ethnographic decision model (EDM) of hydrogen fuel cell vehicle (FCV) adoption using interviews with California residents that either actually adopted an FCV or “seriously considered” doing so before deciding against it. We developed an initial model from 25 semi-structured interviews in which respondents self-described their decision-making processes. We iteratively tested and refined the model in a second round of 53 structured interviews. The final model consists of a first stage that assesses FCV adoption feasibility and a second stage that compares FCVs to other vehicle types. The model ultimately correctly predicts 86.8% of cases in the sample. In the first stage, respondents preferred to satisfy their need for a primary refueling station near home but a substantial number were willing to rely on a station near or on the way to work or other destination. Most drivers required a convenient backup station and a means of managing long-distance trips. Vehicle size options eliminated a few respondents. None rejected FCV adoption due to insufficient driving range. In the second stage, nearly all drivers engaged in some kind of cost comparison, though the factors considered varied greatly. Most opted for what they viewed as the less costly option, although a few FCV adopters and non-adopters were willing to pay more for their more preferred option. EDM is a promising qualitative research method for generating insights into how people navigate the decision whether or not to get an alternative-fuel vehicle. 相似文献
65.
This work presents a classification of the manufacturing strategies of large Spanish industrial companies in Spain. For this purpose the various international empirical studies on alternative manufacturing strategies have been taken as a reference, reviewed and compared. The database used in this study is made up of information on 114 factories and has been designed using the information from a survey mailed to the industrial companies which have production plants in Spain and which in the financial year of 1994 (reference date of this research) employed over 200 workers. Cluster analysis methodology has been used and the classification criterion taken was the competitive advantages or strengths of each factory concerning the five competitive priorities in manufacturing: efficiency, flexibility, quality, delivery and customer service. Finally, this work identifies a taxonomy of the manufacturing strategies of a sample of the largest industrial companies in Spain, differentiating three alternative production strategies: flexible marketoriented manufacturers, low-cost quality manufacturers and delivery-based manufacturers. Large industrial companies analysed compete in manufacturing, basically following a choice of three criteria: flexibility, quality or delivery. The companies belonging to each of the three categories identified maintain common and lasting manufacturing objectives and policies. 相似文献
66.
67.
Jorge R. Chávez Fuentes Oscar R. González W. Steven Gray 《International journal of control》2018,91(6):1460-1472
This paper presents a symmetric Kronecker product analysis of independent and identically distributed jump linear systems to develop new, lower dimensional equations for the stability and performance analysis of this type of systems than what is currently available. In addition, new closed form expressions characterising multi-parameter relative sensitivity functions for performance metrics are introduced. The analysis technique is illustrated with a distributed fault-tolerant flight control example where the communication links are allowed to fail randomly. 相似文献
68.
Oscar J Santiesteban J Manuel Perez 《Small (Weinheim an der Bergstrasse, Germany)》2014,10(6):1202-1211
A magnetic nanosensor‐based method is described to screen a library of drugs for potential binding to toxins. Screening is performed by measuring changes in the magnetic relaxation signal of the nanosensors (bMR nanosensors) in aqueous suspension upon addition of the toxin. The Anthrax lethal factor (ALF) is selected as a model toxin to test the ability of our bMR nanosensor‐based screening method to identify potential inhibitors of the toxin. Out of 30 molecules screened, sulindac, naproxen and fusaric acid are found to bind LF, with dissociation constants in the low micromolar range. Further biological analysis of the free molecules in solution indicate that sulindac and its metabolic products inhibited LF cytotoxicity to macrophages with IC50 values in the micromolar range. Meanwhile, fusaric acid is found to be less effective at inhibiting LF cytotoxicity, while naproxen does not inhibit LF toxicity. Most importantly, when the sulindac and fusaric acid‐bMR nanosensors themselves are tested as LF inhibitors, as opposed to the corresponding free molecules, they are stronger inhibitors of LF with IC50 values in the nanomolar range. Taken together, these studies show that a bMR nanosensors‐based assay can be used to screen known drugs and other small molecules for inhibitor of toxins. The method can be easily modified to screen for inhibitors of other molecular interactions and not only the selected free molecule can be study as potential inhibitors but also the bMR nanosensors themselves achieving greater inhibitory potential. 相似文献
69.
Antonio J. Ruiz-Ruiz Oscar Canovas Pedro E. Lopez-de-Teruel 《Mobile Networks and Applications》2013,18(3):310-325
This paper introduces a multisensor architecture to fuse data acquired from different sensors available in commodity smartphones in order to build accurate location-based services, and pursuing a good balance between accuracy and performance. Using scale invariant features from the images captured using the smartphone camera, we perform a matching process against previously obtained images to determine the current location of the device. Several refinements are introduced to improve the performance and the scalability of our proposal. Location fingerprinting, based on IEEE 802.11, will be used to determine a cluster of physical points, or zone, where the device seems to be according to the received signal strength. In this way, we will reduce the number of images to analyze to those contained in the tentative zone. Additionally, accelerometers will also be considered in order to improve the system performance, by means of a motion estimator. This set of techniques enables a wide range of location-based applications. 相似文献
70.
The Celta pig is a native breed adapted to the north of Spain and extensive production system. The objective was to study the effects of sex and crossbreeding on carcass characteristics and meat quality. Samples were taken from longissimus dorsi muscle of 52 pigs of three different groups [Celta pure breed (C), Celta crossed with Landrace (C × L) and Celta crossed with Duroc (C × D)]. 相似文献