全文获取类型
收费全文 | 3004篇 |
免费 | 264篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 24篇 |
综合类 | 2篇 |
化学工业 | 631篇 |
金属工艺 | 47篇 |
机械仪表 | 66篇 |
建筑科学 | 101篇 |
矿业工程 | 5篇 |
能源动力 | 67篇 |
轻工业 | 610篇 |
水利工程 | 45篇 |
石油天然气 | 12篇 |
无线电 | 128篇 |
一般工业技术 | 477篇 |
冶金工业 | 720篇 |
原子能技术 | 1篇 |
自动化技术 | 334篇 |
出版年
2024年 | 4篇 |
2023年 | 24篇 |
2022年 | 29篇 |
2021年 | 73篇 |
2020年 | 59篇 |
2019年 | 79篇 |
2018年 | 124篇 |
2017年 | 131篇 |
2016年 | 144篇 |
2015年 | 115篇 |
2014年 | 106篇 |
2013年 | 233篇 |
2012年 | 202篇 |
2011年 | 227篇 |
2010年 | 149篇 |
2009年 | 122篇 |
2008年 | 108篇 |
2007年 | 144篇 |
2006年 | 71篇 |
2005年 | 61篇 |
2004年 | 64篇 |
2003年 | 61篇 |
2002年 | 66篇 |
2001年 | 43篇 |
2000年 | 32篇 |
1999年 | 40篇 |
1998年 | 271篇 |
1997年 | 161篇 |
1996年 | 94篇 |
1995年 | 49篇 |
1994年 | 34篇 |
1993年 | 36篇 |
1992年 | 10篇 |
1991年 | 15篇 |
1990年 | 7篇 |
1989年 | 6篇 |
1988年 | 7篇 |
1987年 | 6篇 |
1986年 | 3篇 |
1985年 | 7篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1978年 | 5篇 |
1977年 | 7篇 |
1976年 | 23篇 |
1973年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有3270条查询结果,搜索用时 15 毫秒
131.
I. Rodríguez C. D. Pérez-Segarra J. E. Jaramillo 《Numerical Heat Transfer, Part A: Applications》2013,63(12):1051-1074
The unsteady laminar heat transfer and fluid flow phenomena inside a water storage tank during its static mode of operation and submitted to heat losses to the environment has been investigated by means of CFD and heat transfer numerical simulations. A parametric study has been carried out considering several situations and varying the aspect ratio, insulation thickness, initial temperature, and tank volume. In order to characterize the cooling process, a nondimensional analysis has been performed. From the analysis of the results of several detailed numerical simulations, correlations for the Nusselt number at the lateral, top, and bottom walls have been obtained. The verification of the mathematical model assumed, together with the verification and validation of the results, have also been pointed out. 相似文献
133.
134.
Characterization of novel hyaluronic acid matrix systems for vaginal administration of metronidazole
下载免费PDF全文
![点击此处可从《应用聚合物科学杂志》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Polymers such as Hyaluronic acid (HA), Polyethylene glycol‐400 (PEG‐400) and Xanthan Gum (XG) are promising in drug delivery applicationsbecause of their biomedical and pharmaceutical potential applications. In HA 2%‐PEG 400 systems, the effect of pH and PEG‐400 concentration were evaluated. The viscosity of HA‐PEG 400 formulations slightly increased with PEG‐400 concentration. Viscoelastic properties and shear thinning character was strongly dependent on pH. Structured systems were obtained at pH 3, with an increase of several orders of magnitude in zero‐shear viscosity values. When XG 1% structured system is added on HA (0, 0.5, and 2%) and PEG‐400 5%, a sharp increase of viscosity can be observed, obtaining a gel‐like behaviour for HA 0.5%‐XG 1%‐PEG 400 5% formulation. Finally, metronidazole release profiles in HA 2% formulations with different PEG‐400 concentrations at pH 4.5 were studied. At least 90% of metronidazole was releasedat 24 h. However, the addition of XG 1% to the HA (0.5 and 2%)‐PEG 400 5% systems delayed the drug release. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41313. 相似文献
135.
Miguel-González Celia García-Díaz Manuel Pereiras Bruno Vigil Miguel Rodríguez de Castro Alejandro 《Journal of Mechanical Science and Technology》2021,35(7):2929-2938
Journal of Mechanical Science and Technology - The present study focuses on the numerical modelling of gas-jet wiping process. Many processes involving liquids are necessary during steel... 相似文献
136.
137.
J. Saúl García-Pérez Sara P. Cuéllar-Bermúdez Alejandra Arévalo-Gallegos José Rodríguez-Rodríguez Hafiz M. N. Iqbal Roberto Parra-Saldivar 《International journal of molecular sciences》2016,17(9)
Supercritical fluid extraction (SFE) is a sustainable technique used for the extraction of lipophilic metabolites such as pigments and fatty acids. Arnica plant is considered a potential candidate material with high antioxidant and antimicrobial activities. Therefore, in this study, a locally available Heterotheca inuloides, also known as Mexican arnica, was analyzed for the extraction of high-value compounds. Based on different pressure (P), temperature (T), and co-solvent (CoS), four treatments (T) were prepared. A maximum 7.13% yield was recovered from T2 (T = 60 °C, P = 10 MPa, CoS = 8 g/min), followed by 6.69% from T4 (T = 60 °C, P = 30 MPa, CoS = 4 g/min). Some bioactive sesquiterpenoids such as 7-hydroxycadalene, caryophyllene and δ-cadinene were identified in the extracts by GC/MS. The fatty acid profile revealed that the main components were palmitic acid (C16:0), followed by linoleic acid (C18:2ω6c), α-linolenic acid (C18:3ω3) and stearic acid (C18:0) differing in percent yield per treatment. Antibacterial activities were determined by the agar diffusion method, indicating that all the treatments exerted strong antibacterial activity against S. aureus, C. albicans, and E. coli strains. The antioxidant capacity of the extracts was also measured by three in vitro assays, DPPH, TEAC and FRAP, using Trolox as a standard. Results showed high antioxidant capacity enabling pharmaceutical applications of Mexican arnica. 相似文献
138.
Antioxidant ability of potato (Solanum tuberosum) peel extracts to inhibit soybean oil oxidation
下载免费PDF全文
![点击此处可从《European Journal of Lipid Science and Technology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
139.
A first approach towards the development of geographical origin tracing models for North Moroccan olive oils based on triacylglycerols profiles
下载免费PDF全文
![点击此处可从《European Journal of Lipid Science and Technology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
140.