全文获取类型
收费全文 | 426篇 |
免费 | 24篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 136篇 |
金属工艺 | 8篇 |
机械仪表 | 2篇 |
建筑科学 | 21篇 |
能源动力 | 8篇 |
轻工业 | 94篇 |
水利工程 | 2篇 |
石油天然气 | 1篇 |
无线电 | 34篇 |
一般工业技术 | 53篇 |
冶金工业 | 42篇 |
原子能技术 | 1篇 |
自动化技术 | 48篇 |
出版年
2022年 | 9篇 |
2021年 | 15篇 |
2020年 | 5篇 |
2019年 | 12篇 |
2018年 | 10篇 |
2017年 | 8篇 |
2016年 | 14篇 |
2015年 | 10篇 |
2014年 | 13篇 |
2013年 | 24篇 |
2012年 | 17篇 |
2011年 | 30篇 |
2010年 | 19篇 |
2009年 | 17篇 |
2008年 | 24篇 |
2007年 | 27篇 |
2006年 | 13篇 |
2005年 | 18篇 |
2004年 | 21篇 |
2003年 | 11篇 |
2002年 | 13篇 |
2001年 | 4篇 |
2000年 | 6篇 |
1999年 | 8篇 |
1998年 | 11篇 |
1997年 | 10篇 |
1996年 | 12篇 |
1995年 | 7篇 |
1994年 | 9篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1991年 | 8篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 8篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1976年 | 2篇 |
1975年 | 1篇 |
排序方式: 共有451条查询结果,搜索用时 15 毫秒
91.
Golnoosh Farnadi Geetha Sitaraman Shanu Sushmita Fabio Celli Michal Kosinski David Stillwell Sergio Davalos Marie-Francine Moens Martine De Cock 《User Modeling and User-Adapted Interaction》2016,26(2-3):109-142
A variety of approaches have been recently proposed to automatically infer users’ personality from their user generated content in social media. Approaches differ in terms of the machine learning algorithms and the feature sets used, type of utilized footprint, and the social media environment used to collect the data. In this paper, we perform a comparative analysis of state-of-the-art computational personality recognition methods on a varied set of social media ground truth data from Facebook, Twitter and YouTube. We answer three questions: (1) Should personality prediction be treated as a multi-label prediction task (i.e., all personality traits of a given user are predicted at once), or should each trait be identified separately? (2) Which predictive features work well across different on-line environments? and (3) What is the decay in accuracy when porting models trained in one social media environment to another? 相似文献
92.
Fabien Seyfert Matteo Oldoni Martine Olivi Sanda Lefteriu Damien Pacaud 《国际射频与微波计算机辅助工程杂志》2015,25(8):647-654
In this article, we present a method to recover electrical parameters of filters embedded in a multiplexer for which scattering measurements are given. Unlike other approaches proposed for this problem, this method does not require a priori knowledge of the scattering parameters of the junction. This feature renders the procedure well suited for tuning purposes or for fault diagnosis. Technically, the algorithm starts with a rational approximation step, to derive a rational representation of certain scattering parameters of the multiplexer. This representation is then used in a second step to identify an electrical model of each filter. This second step relies on a rational interpolation technique used to extract the filter's responses. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:647–654, 2015. 相似文献
93.
Margherita Mascia Simon Hu Ke Han Robin North Martine Van Poppel Jan Theunis Carolien Beckx Martin Litzenberger 《Networks and Spatial Economics》2017,17(1):269-291
This paper investigates the effectiveness of traffic management tools, including traffic signal control and en-route navigation provided by variable message signs (VMS), in reducing traffic congestion and associated emissions of CO2, NOx, and black carbon. The latter is among the most significant contributors of climate change, and is associated with many serious health problems. This study combines traffic microsimulation (S-Paramics) with emission modeling (AIRE) to simulate and predict the impacts of different traffic management measures on a number traffic and environmental Key Performance Indicators (KPIs) assessed at different spatial levels. Simulation results for a real road network located in West Glasgow suggest that these traffic management tools can bring a reduction in travel delay and BC emission respectively by up to 6 % and 3 % network wide. The improvement at local levels such as junctions or corridors can be more significant. However, our results also show that the potential benefits of such interventions are strongly dependent on a number of factors, including dynamic demand profile, VMS compliance rate, and fleet composition. Extensive discussion based on the simulation results as well as managerial insights are provided to support traffic network operation and control with environmental goals. The study described by this paper was conducted under the support of the FP7-funded CARBOTRAF project. 相似文献
94.
Françlois Jollet Philippe Maire Martine Gautier Jean-Paul Duraud Claude Le Gressus 《Journal of the American Ceramic Society》1988,71(9):396-C
Because of their method of preparation, ceramics contain point defects, the concentration of which may vary from the center to the boundary of the grains, which may change the bulk properties of the material. The electronic structure of the oxygen-related defects has been studied by electron spectroscopy in yttria ceramics submitted to various heating conditions under controlled atmospheres. The differences in the mechanical and electrical behaviors are observed to correlate with the defect content. 相似文献
95.
Madeleine Dubois Martine Croset Georges Némoz Michel Lagarde Annie-France Prigent 《Lipids》1992,27(10):746-754
Feeding oils of different fatty acid composition modifies the fatty acid composition of cardiac membrane phospholipids, thereby
inducing changes in cardiac contractility and altering response of adenylate cyclase to catecholamines. In the present study,
the effect of such dietary manipulations on cyclic nucleotide phosphodiesterase, which is involved in the control of cyclic
nucleotide intracellular levels and in the control of cardiac contractility, was investigated. Rats were fed either a saturated
fatty acid-enriched diet (8 weight percent [%] coconut oil +2% sunflower oil), an n−6 fatty acid-enriched diet (10% sunflower
oil) or an n−3 fatty acid-enriched diet (8% fish oil +2% sunflower oil). The fatty acid composition of cardiac phospholipids,
as well as the nonesterified fatty acid content of heart were markedly altered by the diets. The 18∶2n−6 and 20∶4n−6 content
of cardiac phospholipids was markedly (−49%) depressed by fish oil as compared with sunflower oil feeding, but the nonesterified
fatty acid level of heart membrane was lowest in coconut oil-fed rats. In addition, fish oil feeding more drastically depressed
the n−6/n−3 fatty acid ratio in the nonesterified fatty acid pool than in cardiac phospholipids. Cyclic AMP phosphodiesterase
activity was the lowest in both the particulate and soluble fractions of heart from rats fed sunflower oil, whereas cyclic
GMP phosphodiesterase activity was not altered by the diets. Cyclic AMP phosphodiesterase activity was decreased by 18 and
12% in heart membranes of the sunflower oil group as compared to that of the coconut oil and fish oil groups, respectively.
In heart cytosol, the activity decreased by 30% when compared with the activity of the coconut oil group. Additionalin vitro experiments showed that polyunsaturated fatty acids were more potent inhibitors of cyclic AMP phosphodiesterase than saturated
fatty acids. These results suggest that polyunsaturated fatty acid-enriched diets might decrease heart cyclic AMP phosphodiesterase
activity by increasing non-esterified polyunsaturated fatty acids, especially those of the n−6 series, but more complex and
indirect mechanisms are very likely to be involved. 相似文献
96.
97.
Rochat D Mohammadpoor K Malosse C Avand-Faghih A Lettere M Beauhaire J Morin JP Pezier A Renou M Abdollahi GA 《Journal of chemical ecology》2004,30(2):387-407
Laboratory and field investigations were carried out to characterize the chemical communication system of the date palm fruit stalk borer, Oryctes elegans, and to develop pheromone-based trapping in Eastern Iran. Adults of both sexes feeding on date palm pieces attracted conspecifics, whereas date palm alone was minimally attractive. Males were twice as attractive as females. More beetles were captured at the palm crown than at ground level. Odors from adults feeding on sugarcane were sampled and analyzed by gas chromatography and mass spectrometry. Whereas females did not emit sex specific volatiles, males emitted a blend of 4-methyloctanoic acid (1: major component) and ethyl 4-methyloctanoate (2), occasionally mixed with minor components: 4-methyloctanyl acetate (3), methyl 4-methyloctanoate (4), 4-methyloctanol (5), and nonanyl acetate (6). Electroantennography and field trapping experiments demonstrated that compound 1 is an essential component of the male aggregation pheromone of O. elegans. It was barely attractive by itself but synergistic with fresh date palm odor. It attracted many more beetles than any of compounds 2-6. The addition of one or several of compounds 2-6 to 1 did not improve trap captures. During the course of 2 years, we captured 4000 beetles, with a weekly average of 6.3 beetles/trap, and were able to monitor the seasonal flight of O. elegans. Our results provide the basis for developing mass trapping for control of this pest. 相似文献
98.
Chenal Alexandre; Nizard Philippe; Forge Vincent; Pugniere Martine; Roy Marie-Odile; Mani Jean-Claude; Guillain Florent; Gillet Daniel 《Protein engineering, design & selection : PEDS》2002,15(5):383-391
We investigated whether the structural and functional behaviorsof two unrelated protein domains were modified when fused. TheIgG-binding protein ZZ derived from staphylococcal protein Awas fused to the N- and/or C-terminus of the diphtheria toxintransmembrane domain (T). T undergoes a conformational changefrom a soluble native state at neutral pH to a molten globule-likestate at acidic pH, leading to its interaction with membranes.We found that this molten globule state was not connected tothe GdnHCl-induced unfolding pathway of T. The pH-induced transitionof T, and also the unfolding of T and ZZ at neutral and acidicpH, were unchanged whether the domains were isolated or fused.The position of ZZ, however, influenced the solubility of Tnear its pKi. SPR measurements revealed that T has a high affinityfor membranes, isolated or within the fusion proteins (KD<10-11 M). This work shows that in the case of T and ZZ, thefusion of protein domains with different stabilities does notalter the structural changes involved in folding and function.This supports the use of T as a soluble membrane anchor. 相似文献
99.
There has long been a need to experimentally measure the dynamic contact conditions of important engineering tribological systems, especially those with polymeric bearing surfaces that prove difficult to model. In order to experimentally quantify the dynamic contact conditions of geometrically complex polymeric bearing surfaces, a composite sensor material has been developed. In this study, qualitative morphological analysis of virgin ultrahigh molecular weight polyethylene (UHMWPE) and carbon black (CB) powders, as well as UHMWPE and CB powder mixtures of varying percentages was performed using field emission scanning electron microscopy (FESEM). Quantitative structure and friction analysis using atomic force microscopy (AFM) was performed on cryoultrasectioned block surfaces of compression-molded CB/UHMWPE composite. In addition, the mechanical properties of the composites were quantified using tensile testing, and the force dependence of the electrical properties was examined under dynamic compressive loading. 相似文献
100.
This paper presents a narrowband statistical analysis of the field distribution inside a road tunnel. Both fixed and mobile antennas are situated inside the tunnel and the transmitting frequency is 2.1 GHz. A theoretical propagation model based on the image theory is first used and the results are then compared to those obtained from experiments carried out either in an empty tunnel or in presence of traffic. 相似文献