全文获取类型
收费全文 | 106269篇 |
免费 | 2096篇 |
国内免费 | 723篇 |
专业分类
电工技术 | 1755篇 |
综合类 | 103篇 |
化学工业 | 18003篇 |
金属工艺 | 4033篇 |
机械仪表 | 3203篇 |
建筑科学 | 3510篇 |
矿业工程 | 579篇 |
能源动力 | 2716篇 |
轻工业 | 8963篇 |
水利工程 | 1127篇 |
石油天然气 | 2467篇 |
武器工业 | 44篇 |
无线电 | 9453篇 |
一般工业技术 | 22268篇 |
冶金工业 | 17545篇 |
原子能技术 | 2828篇 |
自动化技术 | 10491篇 |
出版年
2022年 | 1010篇 |
2021年 | 1578篇 |
2020年 | 1190篇 |
2019年 | 1355篇 |
2018年 | 2257篇 |
2017年 | 2243篇 |
2016年 | 2653篇 |
2015年 | 1747篇 |
2014年 | 2564篇 |
2013年 | 5442篇 |
2012年 | 3999篇 |
2011年 | 4907篇 |
2010年 | 3834篇 |
2009年 | 4073篇 |
2008年 | 4348篇 |
2007年 | 4174篇 |
2006年 | 3597篇 |
2005年 | 3125篇 |
2004年 | 2920篇 |
2003年 | 2717篇 |
2002年 | 2599篇 |
2001年 | 2211篇 |
2000年 | 2189篇 |
1999年 | 2089篇 |
1998年 | 4141篇 |
1997年 | 3039篇 |
1996年 | 2386篇 |
1995年 | 1952篇 |
1994年 | 1743篇 |
1993年 | 1772篇 |
1992年 | 1375篇 |
1991年 | 1276篇 |
1990年 | 1385篇 |
1989年 | 1363篇 |
1988年 | 1210篇 |
1987年 | 1169篇 |
1986年 | 1160篇 |
1985年 | 1236篇 |
1984年 | 1043篇 |
1983年 | 1021篇 |
1982年 | 911篇 |
1981年 | 898篇 |
1980年 | 834篇 |
1979年 | 826篇 |
1978年 | 785篇 |
1977年 | 908篇 |
1976年 | 1050篇 |
1975年 | 712篇 |
1974年 | 659篇 |
1973年 | 643篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
O Bernard B Chachuat A Hélias B Le Dantec B Sialve J-P Steyer L Lardon P Neveu S Lambert J Gallop M Dixon P Ratini A Quintabà S Frattesi J M Lema E Roca G Ruiz J Rodriguez A Franco P Vanrolleghem U Zaher D J W De Pauw K De Neve K Lievens D Dochaine O Schoefs H Fibrianto R Farina V Alcaraz Gonzalez V Gonzalez Alvarez P Lemaire J A Martinez F Esandi O Duclaud J F Lavigne 《Water science and technology》2005,52(1-2):457-464
The TELEMAC project brings new methodologies from the Information and Science Technologies field to the world of water treatment. TELEMAC offers an advanced remote management system which adapts to most of the anaerobic wastewater treatment plants that do not benefit from a local expert in wastewater treatment. The TELEMAC system takes advantage of new sensors to better monitor the process dynamics and to run automatic controllers that stabilise the treatment plant, meet the depollution requirements and provide a biogas quality suitable for cogeneration. If the automatic system detects a failure which cannot be solved automatically or locally by a technician, then an expert from the TELEMAC Control Centre is contacted via the internet and manages the problem. 相似文献
32.
Y. K. Cheung W. G. Jin O. C. Zienkiewicz 《International journal for numerical methods in engineering》1991,32(1):63-78
The application of the Trefftz method for calculating wave forces on offshore structures is presented. Indirect and direct formulations using complete and non-singular systems of Trefftz functions for the Helmholtz equation are posed in this paper. An effective technique using different interpolation functions for the velocity potential and wave force are suggested to improve the computational accuracy of the wave force. The numerical examples show that the present method is highly efficient and accurate. 相似文献
33.
R. Wongmaneerung W. Chaisan O. Khamman R. Yimnirun S. Ananta 《Ceramics International》2008,34(4):813-817
The potential of the vibro-milling technique as a simple method to obtain usable quantities of single-phase electroceramic powders with nanosized particles was examined. A detailed study considering the role of both milling time and firing condition on phase formation and particle size of the final product was performed. The calcination temperature for the formation of the desired phase was lower when longer milling times have been applied. More importantly, by employing an appropriate choice of the milling time and calcination condition, high purity electroceramic nanopowders have been successfully prepared with a simple solid-state reaction method. 相似文献
34.
I. D. Kashcheev S. N. Sychev M. N. Dunaeva L. A. Karpets P. A. Emel’yanov O. S. Ryakhova 《Refractories and Industrial Ceramics》2008,49(2):131-134
Compositions have been developed for nonshrinking vibrocast thermally insulating light refractory concretes with densities
of 1.0, 1.3, 1.5, and 1.8 g/cm3 for temperatures of use up to 1400°C. The structure and properties have been examined for the concrete of density 1.3 g/cm3.
__________
Translated from Novye Ogneupory, No. 4, pp. 29–32, April, 2008. 相似文献
35.
Nguyen An Tien I. Ya. Mittova O. V. Almjasheva S. A. Kirillova V. V. Gusarov 《Glass Physics and Chemistry》2008,34(6):756-761
Nanocrystalline LaFeO3 is prepared by the dehydration of coprecipitated lanthanum and iron(III) hydroxides. It is shown that the behavior of the samples during heating and the size distribution of LaFeO3 nanocrystals can be considerably different depending on the scheme used for coprecipitation of lanthanum and iron hydroxides; independently of the method employed for coprecipitation of the initial compounds, sintering of the samples at 950°C leads to the formation of lanthanum orthoferrite crystals up to 100 nm in size. 相似文献
36.
I. A. Zvereva O. I. Silyukov A. V. Markelov A. B. Missyul’ M. V. Chislov I. A. Rodionov D. -Sh. Li 《Glass Physics and Chemistry》2008,34(6):749-755
The processes of phase formation in the Na2CO3-TiO2 and Na2CO3-TiO2-Nd2O3 systems are investigated in the temperature range 600–900°C. The high-temperature solid-phase reactions underlying the process of formation of complex oxide NaNdTiO4 are studied. It is established that the synthesis of the NaNdTiO4 compound occurs through the reaction of the intermediate product Na8Ti5O14 with neodymium oxide in the temperature range 720–780°C. The optimum method is proposed for synthesizing NaNdTiO4, which makes it possible to reduce the temperature of the synthesis, to avoid the formation of impurities, and to obtain the product in a finely dispersed state. 相似文献
37.
38.
Programs are presented for calculating dusty air flow in ventilation systems, which have been derived from the method of singular
integral equations. They allow one to construct flow lines and determine the velocity pattern for the air in a closed rectangular
region with outlet, flow, and extraction holes; a study is made on the dust particle behavior in the aerodynamic field in
which there may be a rotating cylinder or pumping cylinder; determinations are made of the concentration and grain-size composition
of the dust in the extraction hole; one can construct flow lines and single-particle paths in multicoupled regions of potential
flows containing any number of rotating cylinders and cylinder pumps.
Translated from Novye Ogneupory, No. 5, pp. 53–58, May, 2008. 相似文献
39.
J.A. Giroto A.C.S.C. Teixeira C.A.O. Nascimento R. Guardani 《Chemical Engineering and Processing: Process Intensification》2008,47(12):2361-2369
This paper presents the results of experiments carried out in a laboratory-scale photochemical reactor on the photodegradation of different polymers in aqueous solutions by the photo-Fenton process. Solutions of three polymers, polyethyleneglicol (PEG), polyacrylamide (PAM), and polyvinylpyrrolidone (PVP), were tested under different conditions. The reaction progress was evaluated by sampling and analyzing the total organic carbon concentration in solution (TOC) along the reaction time. The behavior of the different polymers is discussed, based on the evolution of the TOC–time curves. Under specific reaction conditions, the formation and coalescence of solid particles was visually observed. Solids formation occurred simultaneously to a sharp decrease in the TOC of the liquid phase. This may be favorable for the treatment of industrial wastewater containing polymers, since the photodegradation process can be coupled with solid separation systems, which may reduce the treatment cost. 相似文献
40.
By analyzing an oblique ionogram several characteristics, such as LOF, MOF, FMUF, FHLOF, FLLOF, and 2FMOF, can be found. These characteristics are important both for ionospheric studies and for terrestrial communication purposes, as they give information about the sky wave communication conditions in the High Frequency (HF) radio spectrum.A RCS-5B sweeping HF receiver for oblique sounding was installed at Chania (Crete, Greece, 35.7°N, 24.0°E) in April 2005 to perform a radio link with Inskip (UK, 53.5°N, 2.5°W). The receiver, able to record the sounding only as a binary file, was not equipped with a tool to display and scale the recorded trace. This work describes software that is able to do this, consequently increasing the speed of the scaling phase performed by the operator. The usefulness of this software for validating FMUF prediction models is also shown. 相似文献