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51.
László Papp Matthias Sipiczki Imre J. Holb Ida Miklós 《Yeast (Chichester, England)》2014,31(12):475-482
The non‐pathogenic dimorphic fission yeast, Schizosaccharomyces japonicus, could be a suitable model organism for investigation of the genetic background of mycelial growth, as it has a haploid chromosome set and its genome is sequenced. Since earlier results have suggested that its morphological transition required solid substrates, but molecular biological experiments would require hyphae production in a liquid medium, we wanted to find circumstances which would enable hyphae production in liquid media. Several external conditions were investigated, but the strongest inducer was fetal bovine serum (FBS). Its positive effect could be hampered by heat and was dependent on pH, temperature and concentration of the serum. Other protein‐containing compounds, such as peptone and bovine serum albumin or amino acids, proved to be ineffective or weak. Generally, the uninduced and induced mycelial growth of Sz. japonicus could be improved by lower external pH and higher temperature. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
52.
The Yeast ATF1 Acetyltransferase Efficiently Acetylates Insect Pheromone Alcohols: Implications for the Biological Production of Moth Pheromones
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Bao-Jian Ding Ida Lager Sunil Bansal Timothy P. Durrett Sten Stymne Christer Löfstedt 《Lipids》2016,51(4):469-475
Many moth pheromones are composed of mixtures of acetates of long‐chain (≥10 carbon) fatty alcohols. Moth pheromone precursors such as fatty acids and fatty alcohols can be produced in yeast by the heterologous expression of genes involved in insect pheromone production. Acetyltransferases that subsequently catalyze the formation of acetates by transfer of the acetate unit from acetyl‐CoA to a fatty alcohol have been postulated in pheromone biosynthesis. However, so far no fatty alcohol acetyltransferases responsible for the production of straight chain alkyl acetate pheromone components in insects have been identified. In search for a non‐insect acetyltransferase alternative, we expressed a plant‐derived diacylglycerol acetyltransferase (EaDAcT) (EC 2.3.1.20) cloned from the seed of the burning bush (Euonymus alatus) in a yeast system. EaDAcT transformed various fatty alcohol insect pheromone precursors into acetates but we also found high background acetylation activities. Only one enzyme in yeast was shown to be responsible for the majority of that background activity, the acetyltransferase ATF1 (EC 2.3.1.84). We further investigated the usefulness of ATF1 for the conversion of moth pheromone alcohols into acetates in comparison with EaDAcT. Overexpression of ATF1 revealed that it was capable of acetylating these fatty alcohols with chain lengths from 10 to 18 carbons with up to 27‐ and 10‐fold higher in vivo and in vitro efficiency, respectively, compared to EaDAcT. The ATF1 enzyme thus has the potential to serve as the missing enzyme in the reconstruction of the biosynthetic pathway of insect acetate pheromones from precursor fatty acids in yeast. 相似文献
53.
This commentary paper aims to highlight issues associated with the supposed ability to transfer knowledge across networks. In response to the paper “Risks in Organizational Networks: An Exploratory Framework”, (Trkman and Desouza, 2012, pp. 1–17), we argue that the taken-for-granted assumption that knowledge is transferrable represents a risk in itself. We analyze knowledge in networks using a practice perspective – in turn we consider knowledge as enacted in social practices and as context-specific. In contrast with Trkman and Desouza’s paper, we argue that if knowledge is seen as enacted in practice, a framework that maps risks associated with knowledge transfer is limiting. We conclude that, since knowing in practice is emergent and not fully controllable, adopting a set of best practices on how to effectively transfer (or not) knowledge could itself be risky for managers who then believe that knowledge can be treated as a commodity and easily moved about a network. 相似文献
54.
分析仪器和其他传统工业一样,正在信息技术的改造下,向微型化、智能化、自动化和网络化方向发展.分析仪器作为数据获得的源头技术,必将在信息技术发展中起到重要作用,将从被动转向主动,并促进信息技术的发展.分析工作者也将是未来物联网不可或缺的生力军. 相似文献
55.
This article analyzes the possibilities of applying Continuous Improvement principles to the management and maintenance of academic library websites. Current practice is mapped onto Continuous Improvement principles, with evidence distilled from a United Kingdom national survey of academic library web practitioners. The survey data informs a website organizational framework and operational model. The framework describes the setting within which library websites are managed, while the model focuses on library specific aspects to the management and development of their site. 相似文献
56.
Shear deformation and fracture behaviors in polypropylene (PP)‐based model thermoplastic polyolefins (TPOs) were investigated with the Iosipescu shear test. The shear deformation process was monitored in situ via video camera to obtain experimental shear stress–strain curves of model TPOs. Shear fracture mechanisms were studied with optical microscopy and scanning electron microscopy. Macroscopically, the cracks in neat PP propagated along the maximum shear plane, which indicated that mode‐II shear failure existed in neat PP. Microscopically, it was shown that shear fracture initiated in the form of partial, discontinuous inclined microcracks that later coalesced and formed the final continuous crack. The incorporation of rubber in PP could transform the shear fracture process into a stretching process in the shear damage zone. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3201–3214, 2001 相似文献
57.
Comments by on an article entitled "Racial microaggression? How do you know?" by Rafael S. Harris Jr. (see record2008-05553-011). The author states that in our original article we asserted that the racial reality of POC was generally different from the racial reality of White Americans and that often times interpretations of situations and events are the result of worldviews or racial identity. When references are made to POC, or to “visible racial/ethnic groups,” reference is being made not only to the shared cultural characteristics, norms, values, and attitudes of the group (African American, Asian American, American Indian, and Latino/Hispanic American) but to a self-designation of racial identity formed from sociopolitical experiences of unequal social, economic, legal, and political power in U.S. society that are based on visible racial characteristics. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
58.
The concept of territoriality and its relationship to the focus and substance of spatial planning is the subject of much interest at the present time and this paper seeks to contribute to the debate by stepping into the sea. The first part of the paper establishes a framework for considering the spatial planning implications of changing conceptions of territoriality, outlining key sources of territorial innovation and their implications in terms of the development of new units and styles of governance, new challenges for planning practice, and the potential for feedback informing the development of planning theory. The application of the framework is then illustrated in the second part of the paper with reference to the emerging field of maritime spatial planning and in particular to the pioneering work that is being undertaken in Europe. This work is testing established notions of territoriality by highlighting the strong and growing connections between the land and the sea. Here some of the key implications for future spatial planning practice are identified. These indicate that there is a growing recognition of the need for innovation in the territorial units of governance in maritime regions and in the themes, processes and methods of spatial planning in these areas. The paper concludes with some observations on the implications of these findings for the theory of spatial planning. 相似文献
59.
Melchior E. Evers Vladimir Titorenko Wim Harder Ida van der Klei Marten Veenhuis 《Yeast (Chichester, England)》1996,12(10):917-923
We have studied the role of flavin adenine dinucleotide (FAD) in the in vivo assembly of peroxisomal alcohol oxidase (AO) in the yeast Hansenula polymorpha. In previous studies, using a riboflavin (Rf) autotrophic mutant, an unequivocal judgement could not be made, since Rf-limitation led to a partial block of AO import in this mutant. This resulted in the accumulation of AO precursors in the cytosol where they remained separated from the putative peroxisomal AO assembly factors. In order to circumvent the peroxisomal membrane barrier, we have now studied AO assembly in a peroxisome-deficient/Rf-autotrophic double mutant (Δper1.rif1) of H. polymorpha. By sucrose density centrifugation and native gel electrophoresis, three conformations of AO were detected in crude extracts of Δper1.rif1 cells grown under Rf-limitation, namely active octameric AO and two inactive, monomeric forms. One of the latter forms lacked FAD; this form was barely detectable in extracts wild-type and Δper1 cells, but had accumulated in the cytosol of rif1 cells. The second form of monomeric AO contained FAD; this form was also present in Δper1 cells but absent/very low in wild-type and rif1 cells. In vivo only these FAD-containing monomers associate into the active, octameric protein. We conclude that in H. polymorpha FAD binding to the AO monomer is mediated by a yet unknown peroxisomal factor and represents the crucial and essential step to enable AO oligomerization; the actual octamerization and the eventual crystallization in peroxisomes most probably occurs spontaneously. 相似文献
60.
Zhiyuan Jiang Peng Liu Qihui Chen Hung-Jue Sue Tim Bremner Lorenzo P. DiSano 《应用聚合物科学杂志》2020,137(33):48966
Interest in developing high-performance blends for niche applications has grown significantly in efforts to meet ever-increasing harsh environment demands. In this work, four model poly(aryl-ether-ketone)/polybenzimidazole (PAEK/PBI) blends were chosen to study the influence of premixing methods, processing, and matrix polymers, on their mechanical properties. Among the model poly(ether ether ketone) (PEEK) and PBI blends, mechanical properties are greatly enhanced by melt premixing. The molding process mainly affects the matrix crystallinity, which in turn greatly influences fracture toughness of the blend. Poly(ether ketone ketone) (PEKK) and PBI blend exhibits a slightly lower tensile strength and fracture toughness than PEEK/PBI due to the differences in inherent properties of PEEK and PEKK matrices and their interfacial interaction with PBI. The processing−structure–property relationship of PAEK/PBI blends is established to help guide optimal design of high-performance polymer blends for structural applications. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48966. 相似文献