全文获取类型
收费全文 | 803篇 |
免费 | 35篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 12篇 |
综合类 | 2篇 |
化学工业 | 148篇 |
金属工艺 | 15篇 |
机械仪表 | 24篇 |
建筑科学 | 16篇 |
矿业工程 | 1篇 |
能源动力 | 73篇 |
轻工业 | 49篇 |
水利工程 | 5篇 |
石油天然气 | 8篇 |
无线电 | 111篇 |
一般工业技术 | 134篇 |
冶金工业 | 67篇 |
原子能技术 | 6篇 |
自动化技术 | 171篇 |
出版年
2023年 | 7篇 |
2022年 | 18篇 |
2021年 | 39篇 |
2020年 | 30篇 |
2019年 | 40篇 |
2018年 | 33篇 |
2017年 | 45篇 |
2016年 | 37篇 |
2015年 | 20篇 |
2014年 | 48篇 |
2013年 | 70篇 |
2012年 | 39篇 |
2011年 | 49篇 |
2010年 | 42篇 |
2009年 | 28篇 |
2008年 | 21篇 |
2007年 | 21篇 |
2006年 | 21篇 |
2005年 | 17篇 |
2004年 | 13篇 |
2003年 | 13篇 |
2002年 | 6篇 |
2001年 | 3篇 |
2000年 | 7篇 |
1999年 | 9篇 |
1998年 | 21篇 |
1997年 | 13篇 |
1996年 | 13篇 |
1995年 | 18篇 |
1994年 | 11篇 |
1993年 | 13篇 |
1992年 | 10篇 |
1991年 | 7篇 |
1990年 | 6篇 |
1989年 | 11篇 |
1988年 | 6篇 |
1987年 | 4篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1983年 | 3篇 |
1982年 | 7篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1974年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有842条查询结果,搜索用时 15 毫秒
61.
This article presents findings related to the sociomaterial agency of educators and their practice in Norwegian education. Using actor-network theory, we ask how Virtual Learning Environments (VLEs) negotiate the agency of educators and how they shape their teaching practice. Since the same kinds of VLE tools have been widely implemented throughout Norwegian education, it is interesting to study how practices are formed in different parts of the educational system. This research is therefore designed as a case study of two different teaching contexts representing lecturers from a higher education institution and teachers from primary schools. Data are collected by means of interviews, online logging of VLE activities and self-reported personal logs. From the analysis of the data, three main networks of aligned interests can be identified. In each of those, the sociomaterial agency of the teaching practice with VLE is crucial in shaping and consolidating the network. 相似文献
62.
Habib Sahlaoui Mohamed Guedri Habib Sidhom 《Journal of Mechanical Science and Technology》2013,27(9):2769-2774
Software based on molecular structural mechanics approach (MSMA) and using finite element method (FEM) has been developed to predict the Young’s modulus of graphene sheets. Obtained results have been compared to results available in the literature and good agreement has been shown when the same values of uncertainty parameters are used. A sensibility of the models to their uncertainty parameters has been investigated using a stochastic finite element method (SFEM). The different values of the used uncertainty parameters, such as molecular mechanics force field constants k r and k θ , thickness (t) of a graphene sheet and length (L B ) of a carboncarbon bonds, have been collected from the literature. Strong sensibilities of 91% to the thickness and of 21% to the stretching force (k r ) have been shown. The results justify the great difference between Young’s modulus predicted values of the graphene sheets and their large disagreement with experimental results. 相似文献
63.
Aicha O. Cherif Nathalie Leveque Mhamed Ben Messaouda Habib Kallel Alain Tchapla Fathi Moussa 《LWT》2014
A simple strategy to identify triacylglycerols (TAGs) in wild and cultivar peanuts was performed using on line coupling of non-aqueous reversed phase chromatography-electrospray ionization–mass spectrometry (NARP-LC-ESI–MS) with silver nitrate (AgNO3) as a post-column additive. The combination of the structural information given by MS with chromatographic retention laws led to the determination of the structure of TAGs in wild and cultivar peanut oil. In addition, by using the MS5 method, the regio-specificity of the TAGs was determined. It was also demonstrated that in Tunisian peanut oil, the saturates have a preference for the sn-1/sn-3 position for the arachidonic and behenic acids. In the wild variety fatty acids with odd numbers of carbons were found and more TAGs were identified in comparison to the cultivar peanut oil. 相似文献
64.
K. Habib 《Journal of Failure Analysis and Prevention》2010,10(5):427-433
The temperature versus thermal deformation (strain) with respect to time, of different coating films was studied by a non-destructive
technique (NDT) known as shearography. The behavior of organic coatings, i.e., epoxy, a white enamel, or a yellow acrylic
lacquer on carbon steels, was investigated at a temperature range simulating the severe weather temperatures in Kuwait especially
20–60 °C differences between the daylight and the night time temperatures. The investigation focused on determining the in-plane
displacement of the coatings, which amounts to the thermal deformation that results from the applied temperature range. Furthermore,
the investigation also focused on determining the thermal expansion coefficients of coatings and the slope of the plot of
the thermal deformation versus the applied temperature range. A critical (steady state) value of the thermal expansion coefficients
of coatings was used to determine the integrity of the coatings with respect to time. This value was determined from the decreasing,
time-dependent value of the thermal expansion coefficients of coatings. In fact, determination of critical (steady state)
value of the thermal expansion coefficients of coatings could be accomplished independent of parameters such as UV exposure,
humidity, presence of chemical species, and other parameters normally considered in conventional methods of the assessing
of the integrity of coatings. By using the technique of shearography, one needs only to determine the critical (steady state)
value of the thermal expansion coefficients of coatings, regardless of the history of the coating, in order to assess the
integrity of coatings. These results indicate that the technique is a very useful NDT method for determining the critical
value of the thermal expansion coefficients of different coatings and can be used as a 2D-microscope for monitoring the deformation
of the coatings in real-time at a submicroscopic scale. 相似文献
65.
Depiction of precipitation change by elevation in an areaindicates the possibilities of orographic rainfall occurrencesin the mountainous regions. In general, precipitation increaseswith elevation but sometimes inverse cases occur locally due toorographic and meteorological features of the area. Inpractice, prior to any quantitative modeling, qualitativeassessments and interpretations help to have sound foundationsin search for a suitable model. In this article, standardizedpoint cumulative semivariogram (SPCSV) methodology is employedfor identification of the precipitation-elevationrelationship. According to relative positions of theprecipitation and elevation SPCSVs four different precipitationcategories are suggested. The application of the methodologyproposed is presented for the precipitation records from YuccaMountain, Nevada, U.S.A. 相似文献
66.
Amir Daraei Garmakhany Habib Ollah Mirzaei Dr. Mahdi Kashani Nejad Yahya Maghsudlo 《European Journal of Lipid Science and Technology》2008,110(11):1045-1049
The use of coating agents is one effective way to reduce oil absorption in fried products. Reducing the fat content of fried foods by application of coatings is an alternative solution to comply with both health concerns and consumer preferences. The aim of this study was to analyze the effect of hydrocolloids as coating agent on the quantity of oil uptake and on sensory attributes of potato chips. The effect of the coating composition showed that the minimum fat content was related to 1% carboxymethyl cellulose (CMC), 0.5% xanthan, 0.3% guar and 1% xanthan with 21.2, 21.7, 22.4 and 24.8%, respectively, and the highest of fat content was related to blank sample (non-coated), 2% tragacanth, 0.5% guar gum with 49.4, 41.7 and 33.2% of oil content, respectively (p <0.05). The most effective coating agent reduced the oil uptake by 57.03, 55.94, 54.67 and 49.71%, respectively (p <0.05). Sensory evaluation showed that the best color was related to 1% CMC, 0.3% guar and 2% tragacanth, and with respect to flavor evaluation the best flavor was observed in tragacanth 2%, CMC 0.5% and CMC 0.1%, and the best texture referred to tragacanth 2%, CMC 0.5% and CMC 1%. In sensory evaluation, all coated chips got high scores compared with blank (non-coated chips) samples (p <0.05). 相似文献
67.
68.
The kinetics of growth of Al2O3 oxide films made by anode oxidation of ALuminium 1050A with two anodization techniques has been investigatedan compared. The first technique is the classical method based on continuous tension during the complete electrlysis duration, and the second one is the modern method ofpulsed tensions, whcih consists of periodically imposing to the material two anodc tensions E1 and E2 (E1 > E2) during time T1 and T2 until the end on anodization. We have shown that the second technique allows the fabrication of films more rapidly for the same electrolysis duraton. Energy and electrolysis time are saved, making it attractive from an economical viewpoint. This advantage arises from the positive effect of excess heat disiption gathered during the imposition of tension, E1, when E2 is imposed thereafter (recovery effect). The logging of in situ transient responses in the case of pulsed anodization is a significant asset to explain the growth film kinetics obtained with this method. 相似文献
69.
Pre-mRNA splicing is an essential step in gene expression and is catalyzed by two machineries in eukaryotes: the major (U2 type) and minor (U12 type) spliceosomes. While the majority of introns in humans are U2 type, less than 0.4% are U12 type, also known as minor introns (mi-INTs), and require a specialized spliceosome composed of U11, U12, U4atac, U5, and U6atac snRNPs. The high evolutionary conservation and apparent splicing inefficiency of U12 introns have set them apart from their major counterparts and led to speculations on the purpose for their existence. However, recent studies challenged the simple concept of mi-INTs splicing inefficiency due to low abundance of their spliceosome and confirmed their regulatory role in alternative splicing, significantly impacting the expression of their host genes. Additionally, a growing list of minor spliceosome-associated diseases with tissue-specific pathologies affirmed the importance of minor splicing as a key regulatory pathway, which when deregulated could lead to tissue-specific pathologies due to specific alterations in the expression of some minor-intron-containing genes. Consequently, uncovering how mi-INTs splicing is regulated in a tissue-specific manner would allow for better understanding of disease pathogenesis and pave the way for novel therapies, which we highlight in this review. 相似文献
70.