全文获取类型
收费全文 | 720154篇 |
免费 | 12332篇 |
国内免费 | 2256篇 |
专业分类
电工技术 | 12679篇 |
综合类 | 704篇 |
化学工业 | 109072篇 |
金属工艺 | 25911篇 |
机械仪表 | 20556篇 |
建筑科学 | 18083篇 |
矿业工程 | 2760篇 |
能源动力 | 20054篇 |
轻工业 | 68531篇 |
水利工程 | 6775篇 |
石油天然气 | 10964篇 |
武器工业 | 46篇 |
无线电 | 83527篇 |
一般工业技术 | 136203篇 |
冶金工业 | 141898篇 |
原子能技术 | 12820篇 |
自动化技术 | 64159篇 |
出版年
2022年 | 4112篇 |
2021年 | 6584篇 |
2020年 | 4923篇 |
2019年 | 6151篇 |
2018年 | 10332篇 |
2017年 | 10116篇 |
2016年 | 10788篇 |
2015年 | 7658篇 |
2014年 | 12389篇 |
2013年 | 34360篇 |
2012年 | 20064篇 |
2011年 | 27497篇 |
2010年 | 21616篇 |
2009年 | 24016篇 |
2008年 | 24757篇 |
2007年 | 24336篇 |
2006年 | 21486篇 |
2005年 | 19587篇 |
2004年 | 18786篇 |
2003年 | 18517篇 |
2002年 | 17504篇 |
2001年 | 17621篇 |
2000年 | 16309篇 |
1999年 | 17443篇 |
1998年 | 45174篇 |
1997年 | 31527篇 |
1996年 | 23931篇 |
1995年 | 17940篇 |
1994年 | 15584篇 |
1993年 | 15308篇 |
1992年 | 10884篇 |
1991年 | 10232篇 |
1990年 | 9897篇 |
1989年 | 9556篇 |
1988年 | 9001篇 |
1987年 | 7745篇 |
1986年 | 7576篇 |
1985年 | 8737篇 |
1984年 | 8090篇 |
1983年 | 7212篇 |
1982年 | 6796篇 |
1981年 | 6945篇 |
1980年 | 6521篇 |
1979年 | 6256篇 |
1978年 | 5921篇 |
1977年 | 7246篇 |
1976年 | 9554篇 |
1975年 | 5097篇 |
1974年 | 4782篇 |
1973年 | 4988篇 |
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
71.
A. Kathalingam S. Valanarasu Tansir Ahamad Saad M. Alshehri Hyun-Seok Kim 《Ceramics International》2021,47(6):7608-7616
Herein, we report the photosensing property of CdS thin films. CdS thin films were coated onto glass substrates via a spray pyrolysis method using different spray pressures. Prepared films were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and optical and photoluminescence spectroscopy. XRD analysis demonstrated the growth of crystalline CdS films with crystallite sizes varying from 26 to 29 nm depending on the pressure. The SEM and EDAX analyses revealed nearly-stoichiometric CdS films with smooth surfaces and slight variation in grain morphology due to pressure changes. Optical measurements showed a direct bandgap varying from 2.37 eV to 2.42 eV due to pressure changes. A photodetector was also fabricated using the grown CdS films; the fabricated photodetector exhibited good performance depending on the spray pressure. A spray pressure of 1.5 GPa resulted in high photoresponsivity and external quantum efficiency. 相似文献
72.
Golubev N. V. Ignat’eva E. S. Maurus A. A. Ziyatdinova M. Z. Lopatina E. V. Lorenzi R. Paleari A. Sigaev V. N. 《Glass and Ceramics》2021,77(11-12):415-418
Glass and Ceramics - The influence of Al2O3 as an additive and the heat-treatment regime on the luminescence spectra of gallate glass-ceramics was investigated. It is shown that its luminescence... 相似文献
73.
Ana Clara Sabbione Santiago Suárez María Cristina Añón Adriana Scilingo 《International Journal of Food Science & Technology》2019,54(5):1506-1513
In this study, amaranth flour was used as an ingredient to prepare gluten-free cookies. The production process and attributes of amaranth cookies were characterised, and the potential use of amaranth flour as a functional ingredient was analysed. Cookies exhibited a non-uniform reddish brown colour and a cookie factor ratio of 4.5 ± 0.6. Storage studies indicated that after 3 weeks at room temperature cookies presented slight variations in the texture. Simulated gastrointestinal digestion of this product was able to release peptides capable of exerting potential antithrombotic and antihypertensive activities, IC50 values of 0.22 ± 0.04 and 0.23 ± 0.03 mg mL−1 protein, respectively. This work demonstrates for the first time that food made with amaranth flour exerts potential antithrombotic and antihypertensive activity. In conclusion, these amaranth cookies could be an alternative way of incorporating potentially health beneficial products for people who choose a conscious diet, including coeliac or vegan consumers. 相似文献
74.
Norfariza Jamaluddin David C. Stuckey Arbakariya B. Ariff 《Critical reviews in food science and nutrition》2018,58(14):2453-2465
ABSTRACTBacteriocin is a proteinaceous biomolecule produced by bacteria (both Gram-positive and Gram-negative) that exhibits antimicrobial activity against closely related species, and food-borne pathogens. It has recently gained importance and attracted the attention of several researchers looking to produce it from various substrates and bacterial strains. This ushers in a new era of food preservation where the use of bacteriocin in food products will be an alternative to chemical preservatives, and heat treatment which are understood to cause unwanted side effects, and reduce sensory and nutritional quality. However, this new market depends on the success of novel downstream separation schemes from various types of crude feedstocks which are both effective and economic. This review focuses on the downstream separation of bacteriocin from various sources using both conventional and novel techniques. Finally, recommendations for future interesting areas of research that need to be pursued are highlighted. 相似文献
75.
Yana Jorge Polizer-Rocha José M. Lorenzo Daniel Pompeu Isabela Rodrigues Juliana Cristina Baldin Manoela A. Pires Maria Teresa A. Freire Francisco Jose Barba Marco Antonio Trindade 《International Journal of Food Science & Technology》2020,55(3):1018-1024
This study aimed to evaluate the physicochemical characteristics and sensory attributes of beef burgers with the addition of pea fibre as a partial substitute of meat or fat. Three formulations were prepared: control (CON) – similar to the commercial formulation; fibre/less meat (FLM)—5% meat reduction and addition of 1% pea fibre; fibre/less fat (FLF)—7% fat reduction and addition of 1% pea fibre. Non-significant differences were obtained for pH, colour parameters (L* and b*), texture profile, cooking loss and size reduction among formulations. Moreover, sensory analysis with consumers of beef burgers did not indicate differences among the formulations for all the analysed attributes. Therefore, pea fibre is a promising partial replacer for meat and fat in beef burgers due to the preservation of technological parameters and sensory acceptance. 相似文献
76.
The role of the following factors in the selection of technological bases for manufacturing is considered: the accessibility of the machined surfaces; their parameters and dimensional relationships; their position relative to the forces acting; and the uniformity of the margin distribution. 相似文献
77.
Kobrakov K. I. Kurnetsov D. N. Ruchkina A. G. Sharpar N. M. 《Theoretical Foundations of Chemical Engineering》2020,54(5):1052-1056
Theoretical Foundations of Chemical Engineering - New research results, as well as those published earlier by the authors, on the synthesis of azo compounds based on nitroanilines obtained by the... 相似文献
78.
Gomes A. C. S. A. Costa L. C. Brito D. C. Frana R. J. Marques Mnica R. C. 《Polymer Bulletin》2020,77(4):1969-1981
Polymer Bulletin - In this study, we synthesized a new ion-imprinted polymer (IIP) based on introduction of amidoxime groups in acrylonitrile, complexation with Cd2+ ions and polymerization with... 相似文献
79.
Michael A. Clegg Prof. Nicholas C. O. Tomkinson Dr. Rab K. Prinjha Dr. Philip G. Humphreys 《ChemMedChem》2019,14(4):362-385
The bromodomain and extra terminal (BET) family of bromodomain-containing proteins (BCPs) have been the subject of extensive research over the past decade, resulting in a plethora of high-quality chemical probes for their tandem bromodomains. In turn, these chemical probes have helped reveal the profound biological role of the BET bromodomains and their role in disease, ultimately leading to a number of molecules in active clinical development. However, the BET subfamily represents just 8/61 of the known human bromodomains, and attention has now expanded to the biological role of the remaining 53 non-BET bromodomains. Rapid growth of this research area has been accompanied by a greater understanding of the requirements for an effective bromodomain chemical probe and has led to a number of new non-BET bromodomain chemical probes being developed. Advances since December 2015 are discussed, highlighting the strengths/caveats of each molecule, and the value they add toward validating the non-BET bromodomains as tractable therapeutic targets. 相似文献
80.
Bankov S. E. Vesnik M. V. Kravchenko V. F. 《Journal of Communications Technology and Electronics》2020,65(4):398-405
Journal of Communications Technology and Electronics - Abstract—The article presents a rigorous numerical solution, using the Wiener–Hopf method, to the problem of plane wave... 相似文献