全文获取类型
收费全文 | 2299篇 |
免费 | 132篇 |
国内免费 | 11篇 |
专业分类
电工技术 | 42篇 |
综合类 | 4篇 |
化学工业 | 563篇 |
金属工艺 | 50篇 |
机械仪表 | 85篇 |
建筑科学 | 80篇 |
矿业工程 | 1篇 |
能源动力 | 116篇 |
轻工业 | 185篇 |
水利工程 | 34篇 |
石油天然气 | 44篇 |
无线电 | 292篇 |
一般工业技术 | 488篇 |
冶金工业 | 99篇 |
原子能技术 | 16篇 |
自动化技术 | 343篇 |
出版年
2024年 | 8篇 |
2023年 | 49篇 |
2022年 | 94篇 |
2021年 | 134篇 |
2020年 | 98篇 |
2019年 | 103篇 |
2018年 | 135篇 |
2017年 | 109篇 |
2016年 | 131篇 |
2015年 | 84篇 |
2014年 | 135篇 |
2013年 | 218篇 |
2012年 | 124篇 |
2011年 | 155篇 |
2010年 | 105篇 |
2009年 | 86篇 |
2008年 | 67篇 |
2007年 | 55篇 |
2006年 | 63篇 |
2005年 | 35篇 |
2004年 | 44篇 |
2003年 | 27篇 |
2002年 | 19篇 |
2001年 | 26篇 |
2000年 | 24篇 |
1999年 | 18篇 |
1998年 | 18篇 |
1997年 | 9篇 |
1996年 | 20篇 |
1995年 | 15篇 |
1994年 | 15篇 |
1993年 | 14篇 |
1992年 | 19篇 |
1991年 | 14篇 |
1990年 | 10篇 |
1989年 | 11篇 |
1988年 | 14篇 |
1987年 | 18篇 |
1986年 | 11篇 |
1985年 | 16篇 |
1984年 | 13篇 |
1983年 | 13篇 |
1982年 | 9篇 |
1981年 | 5篇 |
1979年 | 9篇 |
1978年 | 8篇 |
1977年 | 5篇 |
1976年 | 10篇 |
1975年 | 6篇 |
1974年 | 5篇 |
排序方式: 共有2442条查询结果,搜索用时 15 毫秒
71.
Lounis Kessal Nicolas Abel Si Mahmoud Karabernou Didier Demigny 《Journal of Real-Time Image Processing》2008,3(3):131-147
Technology evolution makes possible the integration of heterogeneous components as programmable elements (processors), hardware
dedicated blocks, hierarchical memories and buses. Furthermore, an optimized reconfigurable logic core embedded within a System-on-Chip
will associate the performances of dedicated architecture and the flexibility of programmable ones. In order to increase performances,
some of the applications are carried out in hardware, using dynamically reconfigurable logic, rather than software, using
programmable elements. This approach offers a suitable hardware support to design malleable systems able to adapt themselves
to a specific application. This article makes a synthesis of the Ardoise project. The first objective of Ardoise project was
to design and to produce a dynamically reconfigurable platform based on commercial FPGAs. The concept of dynamically reconfigurable
architecture depends partially on new design methodologies elaboration as well as on the programming environment. The platform
architecture was designed to be suitable for real-time image processing. The article outlines mainly the Ardoise tools aspect:
development environment and real-time management of the hardware tasks. The proposed methodology is based on a dynamic management
of tasks according to an application scenario written using C++ language.
相似文献
Lounis KessalEmail: |
72.
73.
Global decentralized discrete sliding mode control of a class of interconnected system using only output information is considered in this paper. Matched and unmatched uncertainties as well as known and unknown interconnections are treated. Bounded time-varying delays are considered within the subsystems and through interconnections. The stability of the reduced-order interconnected systems is analyzed using the Lyapunov–Kraszovskii approach and a novel reachability condition of the composite sliding surfaces is established. The resultant dynamics are proved to be globally asymptotically stable. Simulations show the efficacy of the proposed scheme. 相似文献
74.
Many video-based techniques for assessing postures at work have been developed. Choosing the most appropriate technique should be based on an evaluation of different alternatives in terms of their ability to produce posture information at low input costs, i.e. their cost efficiency. This study compared four video-based techniques for assessing upper arm postures, using cost and error data from an investigation on hairdressers. Labour costs associated with the posture assessments from the video recordings were the dominant factor in the cost efficiency comparison. Thus, a work sampling technique associated with relatively large errors appeared, in general, to be the most cost-efficient because it was labour-saving. Measurement bias and other costs than labour cost for posture assessment influenced the ranking and economic evaluation of techniques, as did the applied measurement strategy, i.e. the numbers of video recordings and repeated assessments of them. PRACTITIONER SUMMARY: The cost efficiency of four video-based techniques for assessing upper arm postures was compared. Work sampling techniques were in general more cost efficient than continuous observations since they were labour-saving. Whilst a labour cost dominated the comparison, 'hidden costs', bias and measurement strategy also influenced this dominance. 相似文献
75.
K. T. Ewida H. El-Salmawy N. N. Atta M. M. Mahmoud 《Clean Technologies and Environmental Policy》2006,8(3):188-197
A technique for controlled burning of rice straw is presented. It relies on well-designed rice straw pellets to be burned in fluidized bed. The developed pellets have high burning rate, no fly ashes emissions and minimum bed fouling. The pellets are manufactured from ground rice straw in a disc pelletizer with the aid of bonding and suitable additive materials. The pellets are tested under controlled conditions in a test rig, which represents a single pellet fluidized bed. It is equipped with a nitrogen gun to eject the pellet and freeze the reaction at any predetermined time during combustion. The ejected pellets are weighed as well as elementary analyzed for both carbon and hydrogen, to calculate the burning rate as well as the combustion efficiency, respectively. The effect of several parameters has been evaluated including straw particle size, pellet size, type and concentration of bonding material as well as anti-sintering additives. Also, the pellets’ mechanical characteristics have been evaluated. It has been found that char combustion phase represents the controlling phase of the pellet combustion. The burning rate is higher as the void fraction of the pellet is higher. Starch showed better combustion and mechanical characteristics out of the five tested bonding materials. Adding kaolin to the pellets results in improving the sintering characteristics of the pellets. The experimental results were compared with two combustion models: the oxygen diffusion controlled and the kinetic-diffusion models. It has been found that oxygen diffusion controlled model more accurately simulates the combustion of the pellet during its char combustion phase. The model has been used to evaluate the effect of some operational parameters on the pellet combustion characteristics such as bed temperature, gas flow and oxygen concentration. 相似文献
76.
Amro A. El-Baz M. Kamal T. Ewida M. Abbas Shouman Mahmoud M. El-Halwagi 《Clean Technologies and Environmental Policy》2005,7(2):78-86
The objective of this paper is to develop a systematic methodology for mass integration in drain systems and watersheds. Mass integration is a holistic approach to the tracking, transformation, and allocation of species and streams. The watershed and drain system is first discretized into reaches. The MFA model developed in part I of this work (Simulation and Application to Ammonium Management in Bahr El-Baqar Drain System) is used to describe the environmental phenomena that affect the fate and transport of targeted species and the operators that characterize the system inputs and outputs as they relate to the surroundings. Next, we develop an integration framework which encompasses sources, sinks, and interception technologies to aid in the development for nitrogen-management strategies. The simulation model was transformed into a synthesis model by introducing optimization variables and including models for the potential management strategies. The problem of minimizing negative environmental impact subject to technical, social, economic, and regulatory constraints was posed as a nonlinear optimization program whose solution identified and synthesized the most effective solution strategies. These mathematical models and management strategies were coded into a computer-aided tool using LINGO programming platform. The program can be readily modified to address a variety of cases. Tradeoffs and sensitivity analysis were established using the devised model. The devised framework was applied to an Egyptian drain system (Bahr El-Baqar) along with the outfall to Lake Manzala. The results of the case study provide solution strategies for nitrogen management along with their technical, economic, and environmental implications. 相似文献
77.
Afzan A. Ayoub Abdel H. Mahmoud Juliana S. Ribeiro Arwa Daghrery Jinping Xu J. Christopher Fenno Anna Schwendeman Hajime Sasaki Renan Dal-Fabbro Marco C. Bottino 《International journal of molecular sciences》2022,23(22)
This study was aimed at engineering photocrosslinkable azithromycin (AZ)-laden gelatin methacryloyl fibers via electrospinning to serve as a localized and biodegradable drug delivery system for endodontic infection control. AZ at three distinct amounts was mixed with solubilized gelatin methacryloyl and the photoinitiator to obtain the following fibers: GelMA+5%AZ, GelMA+10%AZ, and GelMA+15%AZ. Fiber morphology, diameter, AZ incorporation, mechanical properties, degradation profile, and antimicrobial action against Aggregatibacter actinomycetemcomitans and Actinomyces naeslundii were also studied. In vitro compatibility with human-derived dental pulp stem cells and inflammatory response in vivo using a subcutaneous rat model were also determined. A bead-free fibrous microstructure with interconnected pores was observed for all groups. GelMA and GelMA+10%AZ had the highest fiber diameter means. The tensile strength of the GelMA-based fibers was reduced upon AZ addition. A similar pattern was observed for the degradation profile in vitro. GelMA+15%AZ fibers led to the highest bacterial inhibition. The presence of AZ, regardless of the concentration, did not pose significant toxicity. In vivo findings indicated higher blood vessel formation, mild inflammation, and mature and thick well-oriented collagen fibers interweaving with the engineered fibers. Altogether, AZ-laden photocrosslinkable GelMA fibers had adequate mechanical and degradation properties, with 15%AZ displaying significant antimicrobial activity without compromising biocompatibility. 相似文献
78.
Israa M. Shamkh Mohammed Al-Majidi Ahmed Hassen Shntaif Peter Tan Deng Kai Ngoc Nh-Pham Ishrat Rahman Dalia Hamza Mohammad Shahbaz Khan Maii S. Elsharayidi Eman T. Salah Abdullah Haikal Modupe Akintomiwa Omoniyi Mahmoud A. Abdalrahman Tomasz M. Karpinski 《International journal of molecular sciences》2022,23(21)
In recent years, novel strategies to control insects have been based on protease inhibitors (PIs). In this regard, molecular docking and molecular dynamics simulations have been extensively used to investigate insect gut proteases and the interactions of PIs for the development of resistance against insects. We, herein, report an in silico study of (disodium 5′-inosinate and petunidin 3-glucoside), (calcium 5′-guanylate and chlorogenic acid), chlorogenic acid alone, (kaempferol-3,7-di-O-glucoside with hyperoside and delphinidin 3-glucoside), and (myricetin 3′-glucoside and hyperoside) as potential inhibitors of acetylcholinesterase receptors, actin, α-tubulin, arginine kinase, and histone receptor III subtypes, respectively. The study demonstrated that the inhibitors are capable of forming stable complexes with the corresponding proteins while also showing great potential for inhibitory activity in the proposed protein-inhibitor combinations. 相似文献
79.
Steven J. Fliesler Sriganesh Ramachandra Rao Mai N. Nguyen Mahmoud Tawfik KhalafAllah Steven J. Pittler 《International journal of molecular sciences》2022,23(21)
Retinitis pigmentosa-59 (RP59) is a rare, recessive form of RP, caused by mutations in the gene encoding DHDDS (dehydrodolichyl diphosphate synthase). DHDDS forms a heterotetrameric complex with Nogo-B receptor (NgBR; gene NUS1) to form a cis-prenyltransferase (CPT) enzyme complex, which is required for the synthesis of dolichol, which in turn is required for protein N-glycosylation as well as other glycosylation reactions in eukaryotic cells. Herein, we review the published phenotypic characteristics of RP59 models extant, with an emphasis on their ocular phenotypes, based primarily upon knock-in of known RP59-associated DHDDS mutations as well as cell type- and tissue-specific knockout of DHDDS alleles in mice. We also briefly review findings in RP59 patients with retinal disease and other patients with DHDDS mutations causing epilepsy and other neurologic disease. We discuss these findings in the context of addressing “knowledge gaps” in our current understanding of the underlying pathobiology mechanism of RP59, as well as their potential utility for developing therapeutic interventions to block the onset or to dampen the severity or progression of RP59. 相似文献
80.
Pter P. Lakatos Dvid rpd Kardi Anna Rita Galambos Nariman Essmat Kornl Kirly Rudolf Laufer Orsolya Geda Zoltn S. Zdori Tams Tbi Mahmoud Al-Khrasani va Szk 《International journal of molecular sciences》2022,23(17)
Current treatment approaches to manage neuropathic pain have a slow onset and their use is largely hampered by side-effects, thus there is a significant need for finding new medications. Tolperisone, a centrally acting muscle relaxant with a favorable side effect profile, has been reported to affect ion channels, which are targets for current first-line medications in neuropathic pain. Our aim was to explore its antinociceptive potency in rats developing neuropathic pain evoked by partial sciatic nerve ligation and the mechanisms involved. Acute oral tolperisone restores both the decreased paw pressure threshold and the elevated glutamate level in cerebrospinal fluid in neuropathic rats. These effects were comparable to those of pregabalin, a first-line medication in neuropathy. Tolperisone also inhibits release of glutamate from rat brain synaptosomes primarily by blockade of voltage-dependent sodium channels, although inhibition of calcium channels may also be involved at higher concentrations. However, pregabalin fails to affect glutamate release under our present conditions, indicating a different mechanism of action. These results lay the foundation of the avenue for repurposing tolperisone as an analgesic drug to relieve neuropathic pain. 相似文献