全文获取类型
收费全文 | 319692篇 |
免费 | 18556篇 |
国内免费 | 844篇 |
专业分类
电工技术 | 5985篇 |
综合类 | 342篇 |
化学工业 | 58265篇 |
金属工艺 | 10893篇 |
机械仪表 | 9624篇 |
建筑科学 | 8504篇 |
矿业工程 | 1126篇 |
能源动力 | 7764篇 |
轻工业 | 34158篇 |
水利工程 | 3067篇 |
石油天然气 | 4071篇 |
武器工业 | 69篇 |
无线电 | 42162篇 |
一般工业技术 | 64687篇 |
冶金工业 | 51921篇 |
原子能技术 | 5512篇 |
自动化技术 | 30942篇 |
出版年
2021年 | 3026篇 |
2020年 | 3565篇 |
2019年 | 5780篇 |
2018年 | 7327篇 |
2017年 | 7632篇 |
2016年 | 8407篇 |
2015年 | 6764篇 |
2014年 | 8671篇 |
2013年 | 18006篇 |
2012年 | 10753篇 |
2011年 | 12622篇 |
2010年 | 10634篇 |
2009年 | 11272篇 |
2008年 | 11689篇 |
2007年 | 11327篇 |
2006年 | 10037篇 |
2005年 | 8988篇 |
2004年 | 8681篇 |
2003年 | 8445篇 |
2002年 | 7990篇 |
2001年 | 7794篇 |
2000年 | 7448篇 |
1999年 | 6998篇 |
1998年 | 15924篇 |
1997年 | 11379篇 |
1996年 | 8801篇 |
1995年 | 6820篇 |
1994年 | 6022篇 |
1993年 | 5893篇 |
1992年 | 4660篇 |
1991年 | 4302篇 |
1990年 | 4127篇 |
1989年 | 3860篇 |
1988年 | 3715篇 |
1987年 | 3261篇 |
1986年 | 3136篇 |
1985年 | 3682篇 |
1984年 | 3441篇 |
1983年 | 3073篇 |
1982年 | 2890篇 |
1981年 | 3015篇 |
1980年 | 2817篇 |
1979年 | 2677篇 |
1978年 | 2537篇 |
1977年 | 3044篇 |
1976年 | 3743篇 |
1975年 | 2349篇 |
1974年 | 2340篇 |
1973年 | 2354篇 |
1972年 | 1851篇 |
排序方式: 共有10000条查询结果,搜索用时 182 毫秒
51.
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
52.
53.
SPEEK/cSMM membrane for simultaneous electricity generation and wastewater treatment in microbial fuel cell 下载免费PDF全文
54.
Efficacy of Crude and Purified Chitinases (SsChi50) Extracted from Offal Red Scorpion Fish in Biological Control of Chickpea Weevil (Callosobruchus maculatus L.) 下载免费PDF全文
55.
Quality enhancement of the abundant under‐valued crustacean,lobster krill (Munida spp.), during its chilled storage 下载免费PDF全文
Bibiana García‐Soto José M. Miranda Jorge Barros‐Velázquez Santiago P. Aubourg 《International Journal of Food Science & Technology》2015,50(3):708-716
Lobster krill (Munida genus) represents an under‐valued crustacean frequently caught on European fishing banks. In this work, its sensory, microbiological and biochemical qualities were evaluated during chilled storage. Additionally, the effects of a prestorage antimelanosic treatment consisting of soaking in sodium metabisulphite (SMB) solutions at two different concentrations (0.25% and 0.75%) were also studied. SMB prestorage treatment provided lobster specimens that still exhibited acceptable sensory quality after 10 days of storage, while control specimens were unacceptable at that time. SMB treatment also resulted in a significant (P < 0.05) inhibition of microbial growth, mainly of Enterobacteriaceae, psychrotrophes and proteolytic bacteria. Low lipid oxidation levels were observed for all batches; however, a significantly higher (P < 0.05) retention of polyunsaturated fatty acids was found in SMB‐treated lobster, especially in the 0.75% SMB batch. The results presented here open the way to the potential commercialisation of currently under‐utilised lobster krill as a chilled product. 相似文献
56.
ABSTRACTThis paper deals with asymptotic stabilisation of a class of nonlinear input-delayed systems via dynamic output feedback in the presence of disturbances. The proposed strategy has the structure of an observer-based control law, in which the observer estimates and predicts both the plant state and the external disturbance. A nominal delay value is assumed to be known and stability conditions in terms of linear matrix inequalities are derived for fast-varying delay uncertainties. Asymptotic stability is achieved if the disturbance or the time delay is constant. The controller design problem is also addressed and a numerical example with an unstable system is provided to illustrate the usefulness of the proposed strategy. 相似文献
57.
58.
59.
Pasquale Stano Tereza Pereira de Souza Paolo Carrara Emiliano Altamura Erica D’Aguanno Margherita Caputo 《先进材料力学与结构力学》2015,22(9):748-759
Here we report some recent biophysical issues on the preparation of solute-filled lipid vesicles and their relevance to the construction of “synthetic cells.” First, we introduce the “semi-synthetic minimal cells” as the liposome-based cell-like systems, which contain a minimal number of biomolecules required to display simple and complex biological functions. Next, we focus on recent aspects related to the construction of synthetic cells. Emphasis is given to the interplay between the methods of synthetic cell preparation and the physics of solute encapsulation. We briefly introduce the notion of structural and compositional “diversity” in synthetic cell populations. 相似文献
60.
Molecular structure and granule morphology of native and heat‐moisture‐treated pinhão starch 下载免费PDF全文
Vania Z. Pinto Khalid Moomand Nathan L. Vanier Rosana Colussi Franciene A. Villanova Elessandra R. Zavareze Loong‐Tak Lim Alvaro R. G. Dias 《International Journal of Food Science & Technology》2015,50(2):282-289
Pinhão seed is an unconventional source of starch and the pines grow up in native forests of southern Latin America. In this study, pinhão starch was adjusted at 15, 20 and 25% moisture content and heated to 100, 110 and 120 °C for 1 h. A decrease in λ max (starch/iodine complex) was observed as a result of increase in temperature and moisture content of HMT. The ratio of crystalline to amorphous phase in pinhão starch was determined via Fourier transform infra red by taking 1045/1022 band ratio. A decrease in crystallinity occurred as a result of HMT. Polarised light microscopy indicated a loss of birefringence of starch granules under 120 °C at 25% moisture content. Granule size distribution was further confirmed via scanning electron microscopy which showed the HMT effects. These results increased the understanding on molecular and structural properties of HMT pinhão starch and broadened its food and nonfood industrial applications. 相似文献