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41.
Wireless mesh networks facilitate the development of the many group oriented applications by extending the coverage area of
the group communication. Group communication in a wireless mesh network is complicated due to dynamic intermediate mesh points,
access control for communications between different administrative domains, and the absence of a centralized network controller.
In this study, we propose a topology-matching decentralized multi-service group key management scheme for wireless mesh networks.
It allows service providers to update and deliver their group keys to valid members in a distributed manner using the identity-based
encryption scheme. The analysis result indicates that the proposed scheme has advantages with regard to the rekeying cost
and storage overhead for a member and a mesh point in multi-sender group communication environments. The stateless property
is also achieved such that a stateless member, who could not be constantly online, can easily decrypt the rekeying messages
without recording the past history of transmission. 相似文献
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43.
Powder metallurgy processes using sintering are able to form net-shaped products and have been used widely in the production of automobile parts to improve productivity. However, the toughness of powder products is generally poor because they contain pores. Therefore, forged products are used in parts subjected to severe fatigue loads, but in the case of powder products having high toughness, they could substitute for forged products. In this study, the choice of powder materials and production processes, including mixing, compaction, sintering, and heat treatment are studied to produce the clutch disc spline hub of an automobile. For this, three types of materials are selected and processed and the mechanical properties and microstructure of the sample are investigated, along with the performance of a dynamic test carried out under real conditions. 相似文献
44.
Upulee Kanewala James M. Bieman Asa Ben‐Hur 《Software Testing, Verification and Reliability》2016,26(3):245-269
Comprehensive, automated software testing requires an oracle to check whether the output produced by a test case matches the expected behaviour of the programme. But the challenges in creating suitable oracles limit the ability to perform automated testing in some programmes, and especially in scientific software. Metamorphic testing is a method for automating the testing process for programmes without test oracles. This technique operates by checking whether the programme behaves according to properties called metamorphic relations. A metamorphic relation describes the change in output when the input is changed in a prescribed way. Unfortunately, finding the metamorphic relations satisfied by a programme or function remains a labour‐intensive task, which is generally performed by a domain expert or a programmer. In this work, we propose a machine learning approach for predicting metamorphic relations that uses a graph‐based representation of a programme to represent control flow and data dependency information. In earlier work, we found that simple features derived from such graphs provide good performance. An analysis of the features used in this earlier work led us to explore the effectiveness of several representations of those graphs using the machine learning framework of graph kernels, which provide various ways of measuring similarity between graphs. Our results show that a graph kernel that evaluates the contribution of all paths in the graph has the best accuracy and that control flow information is more useful than data dependency information. The data used in this study are available for download at http://www.cs.colostate.edu/saxs/MRpred/functions.tar.gz to help researchers in further development of metamorphic relation prediction methods. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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46.
Yeung Joon Choi Sungik Hur Byeong-Dae Choi Kunihiko Konno Jae W. Park 《Journal of food science》2009,74(1):C17-C24
ABSTRACT: Fish protein isolate were recovered from frozen small croaker using pH shift. The partial enzymatic hydrolysates were fractionated as soluble and insoluble parts. They were dried using the drum dryer and their functional properties were examined. The total nitrogen content of the enzymatic hydrolysates ranged from 12.9% to 13.7%. The degree of hydrolysis of precipitates was 18.2% and 12.2% for croaker hydrolysates treated with Protamex 1.5 MG ( Bacilllus protease complex) and Flavourzyme 500 MG (endoproteases and exoproteases, Aspergillus oryzae ), respectively. The TCA supernatant, after centrifugation of hydrolysates, contained numerous peptides ranging from 100 to 4000 daltons. The solubility of the supernatants was higher than that of the precipitates at 0% to 3% NaCl and pH 2 to 10. The precipitate of Flavourzyme- and Protamex-treated hydrolysates showed a high emulsion activity index value compared to egg white and bovine plasma protein. In addition, the highest emulsion stability was observed for Protamex-treated precipitate hydrolysates. Emulsion stability of Protamex-treated precipitate hydrolysates was comparable to those of protein additives (egg white, bovine plasma protein, and soy protein concentrate). Water and fat binding capacity of precipitates were higher than those of supernatant. The results indicate that precipitate hydrolysate from undersized croaker can be used in processed muscle foods as a functional and nutritional ingredient. 相似文献
47.
Seulah Lee Yeon Ji Suh Seonguk Yang Dong Geun Hong Akihito Ishigami Hangun Kim Jae-Seoun Hur Seung-Cheol Chang Jaewon Lee 《International journal of molecular sciences》2021,22(4)
Oxidative stress, mitochondrial dysfunction, and neuroinflammation are strongly associated with the pathogenesis of Parkinson’s disease (PD), which suggests that anti-oxidative and anti-inflammatory compounds might provide an alternative treatment for PD. Here, we evaluated the neuroprotective effects of evernic aid (EA), which was screened from a lichen library provided by the Korean Lichen Research Institute at Sunchon National University. EA is a secondary metabolite generated by lichens, including Ramalina, Evernia, and Hypogymnia, and several studies have described its anticancer, antifungal, and antimicrobial effects. However, the neuroprotective effects of EA have not been studied. We found that EA protected primary cultured neurons against 1-methyl-4-phenylpyridium (MPP+)-induced cell death, mitochondrial dysfunction, and oxidative stress, and effectively reduced MPP+-induced astroglial activation by inhibiting the NF-κB pathway. In vivo, EA ameliorated MPTP-induced motor dysfunction, dopaminergic neuronal loss, and neuroinflammation in the nigrostriatal pathway in C57BL/6 mice. Taken together, our findings demonstrate that EA has neuroprotective and anti-inflammatory effects in PD models and suggest that EA is a potential therapeutic candidate for PD. 相似文献
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49.
Süleyman Köytepe Maruf Hurşit Demirel Ahmet Gültek Turgay Seçkin 《Polymer International》2014,63(4):778-787
In this study, novel metallo‐supramolecular materials based on terpyridine‐functionalized polyhedral silsesquioxane were synthesized from 4′‐chloro‐2,2′:6′,2″‐terpyridine and amino‐group‐functionalized polyhedral oligomeric silsesquioxane. The obtained terpyridine‐functionalized polyhedral silsesquioxanes were converted to metallo‐supramolecular hybrid materials by coordination polycondensation reaction with Co(II) or Cu(II) ions. The supramolecular polymers created were characterized by means of structure, morphology and stimuli‐responsive performance employing scanning electron microscopy, amperometric techniques and UV–visible and Fourier transform IR spectroscopy. UV?visible and cyclic voltammetry studies showed that both the optical and electrochemical properties of metallo‐supramolecular materials are affected by the substituent at the pyridine periphery. The supramolecular polymers obtained exhibited electrochromism during the oxidation processes of cyclic voltammogram studies. As a result, these terpyridine‐functionalized polyhedral silsesquioxanes are good candidates for electronic, opto‐electronic and photovoltaic applications as smart stimuli‐responsive materials. © 2013 Society of Chemical Industry 相似文献
50.
This study was carried out to develop an easy method for beef freshness using a cyclic voltammetric system. Prime graded (USDA) beef loin at 48 h postmortem was cut into pieces 3 cm thick, packaged into commercial plastic zipper bag, and then stored at 4 °C for 0, 3, 6 and 9 days. A commercial cyclic voltammetry and data processing software were used for this study and the interdigitated electrode was fabricated according to semiconductor manufacturing. The homogenated beef was filtered through Whatman No. 1 filter paper and 250 μL of the filtrate was applied on the interdigitated electrode sensor chip for electrochemical detection. Electrochemical signals changed as storage periods increased. The shape of the cyclic voltammogram changed from a roundish curve to a shapely curve. Redox values (V) also increased during storage. Electrochemical signals matched well with lipid oxidation values (Thiobarbituric acid reactive substances: TBARS). A linear relationship between redox value and TBARS was obtained with a correlation factor of 0.957. Thus, the electrochemical signal of a cyclic voltammetric system can be used as an indicator of beef freshness. 相似文献