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61.
Automated parallel synthesis with multivariate analysis was employed in the optimization of a Pd-catalyzed three-component cascade reaction of 7-buta-2,3-dienyl-1,3-dimethyl-3,7-dihydropurine-2,6-dione with iodobenzene and morpholine (see Scheme 1). Initially a range of reaction factors were analyzed using experimental design to optimize for selectivity, conversion, and impurity levels. Solvents and bases were screened separately as the substantial number of discrete variables involved is unsuited to the fractional factorial design used. Instead, a solvent principal component analysis (PCA) model was used in selection of solvents for screening, so gaining maximum variation in solvent properties. Similarly, tertiary amines were chosen by pKa for screening as bases alongside inorganic salts. This investigation yielded two-fold results, not only in enhancement of the reaction selectivity, but since significantly different findings were obtained on changing the solvent, the importance of the sequence of experimentation is also emphasized. 相似文献
62.
Kate Sanders Sally Fincher Dennis Bouvier Gary Lewandowski Briana Morrison Laurie Murphy Marian Petre Brad Richards Josh Tenenberg Lynda Thomas Richard Anderson Ruth Anderson Sue Fitzgerald Alicia Gutschow Susan Haller Raymond Lister Renée McCauley John McTaggart Christine Prasad Terry Scott Dermot Shinners-Kennedy Suzanne Westbrook Carol Zander 《Expert Systems》2005,22(3):121-128
Abstract: This paper presents a case study of the use of a repeated single‐criterion card sort with an unusually large, diverse participant group. The study, whose goal was to elicit novice programmers' knowledge of programming concepts, involved over 20 researchers from four continents and 276 participants drawn from 20 different institutions. In this paper we present the design of the study and the unexpected result that there were few discernible systematic differences in the population. The study was one of the activities of the National Science Foundation funded Bootstrapping Research in Computer Science Education project (2003). 相似文献
63.
Cross cultural literature has suggested China has a business culture based on family networks or guanxi connections underpinned by strong Confucian ethics. We argue that Chinese business may have distinctly national cultural attributes (that international businesses ignore at their peril) but we reassess the continuing significance of these historical cultural concepts. We query whether a system of networks consolidated during fifty years of state‐owned enterprises can still have application on the considerably larger scale of multinational corporate business of today’s China. Interview data collected from Australian expatriates in China in 2001 is used to assess the relevance of guanxi for effective international operations in China from the perspective of Australian expatriate managers. 相似文献
64.
Yipeng Chen;Zijian Liang;Mark Krstic;Peter Clingeleffer;Kate Howell;Deli Chen;Pangzhen Zhang; 《Australian Journal of Grape and Wine Research》2024,2024(1):7586202
Background and Aims. Rootstocks are widely used in the viticulture industry to manage biotic stress, particularly the infestation of phylloxera, and to improve tolerance to abiotic stress. Grafting grapevines to rootstocks affects the berry quality and may influence the wine composition. This project investigated the impacts of 14 different rootstocks on the berry and wine chemical properties, phenolic profile, and volatile profile of grafted Vitis vinifera L. cv Pinot noir MV6. Methods and Results. This study was conducted at a commercial vineyard located in Mornington Peninsula, Victoria, Australia. The scions of V. vinifera L. cv Pinot noir clone MV6 were grafted onto 14 rootstocks, including 101-14 Millardet et de Grasset (101-14 Mgt), 1103 Paulsen, Selection Oppenheim (SO4), 110 Richter, Schwarzmann, 5C Teleki, 3309 Couderc (3309C), Merbein 5489, Merbein 6262, Merbein 5512, C20, C29, C113, and C114, with own-rooted vines acting as the control group. Berries were collected at harvest in the 2020 and 2021 vintages for small-scale winemaking. The pH, titratable acidity, phenolic content, and antioxidant activity of both the berries and wine were measured using conventional chemical analysis. The phenolic composition of the wine over the two vintages was identified and quantified by high-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (HPLC-QTOF-MS/MS) and HPLC with diode-array detection (HPLC-DAD). The volatile composition was measured by headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). Grafting Pinot noir onto 3309C caused a reduction in the berry and wine pH without affecting the titratable acid. Several rootstocks, such as 1103 Paulsen, SO4, Schwarzmann, and 5C Teleki, reduced the total phenolic content (TPC) in both the berries and wine of Pinot noir. Conversely, Merbein 5489 increased the berry and wine TPC by 15% and 63%, respectively, compared to ungrafted Pinot noir MV6. A similar tendency was also found in the condensed tannin content (CTC), where Merbein 5489 increased the berry and wine CTC by 35% and 112%, respectively, compared to ungrafted vines. Several rootstocks, such as 3309C and Merbein 6262, increased the wine anthocyanin content (especially malvidin 3-O-glucoside), which may contribute to enhanced colour intensity. The concentrations of several ethyl ester compounds in wine responsible for the fruity aroma, including ethyl hexanoate, ethyl octanoate, and ethyl butanoate, were significantly higher in scions grafted to Schwarzmann, 3309C, Merbein 5489, and C29, compared to scions grafted to 101-14 Mgt, 1103 Paulsen, and ungrafted vines. This suggests that rootstock plays an important role in altering the texture and flavour of Pinot noir wine. Conclusions. Grafting Pinot noir to any rootstock in this study caused changes in the phenolic and volatile content of Pinot noir wine, likely affecting the perceived wine quality. Wine from Pinot noir grafted onto Merbein 5489, in particular, with relatively high CTC and anthocyanin content, as well as higher concentrations of volatile compounds contributing to the fruity aroma, represents an attractive option for grafting Pinot noir MV6 in cool climates. Significance of the Study. The present study provides results reflecting the impacts of grapevine rootstocks on Pinot noir berry and wine composition, supporting rootstock selection for Pinot noir. The findings offer guidance to vignerons in choosing suitable rootstocks to manage berry and wine acidity, phenolic accumulation and composition, and volatile profile, thereby improving the wine quality. Furthermore, the results could guide future studies in understanding the roles of rootstocks in regulating the metabolic pathways of phenolic and volatile production in the berries of grafted Pinot noir at the molecular level. 相似文献
65.
Ines Cazin;Kateřina Plevová;Walter Alabiso;Elvira Vidović;Sandra Schlögl; 《Advanced Engineering Materials》2024,26(8):2301699
Dual-wavelength vat photopolymerization 3D printing represents a convenient technology for the fabrication of objects with heterogeneous and locally controlled mechanical properties. By using two λ-orthogonal cross-linking reactions, it is possible to produce soft and stiff photopolymers with a single resin vat by switching the light source. Herein, hybrid acrylate-epoxy resins are selectively cured by using either visible or UV light. At 405 nm, a free radical curing of the acrylate monomers is induced while irradiation with 365 nm triggers an additional cationic ring opening reaction of the epoxy monomer yielding interpenetrating photopolymer networks. In a comprehensive approach, the influence of the resin composition and the applied wavelength on cure kinetics, film morphology, (thermo)mechanical properties, and printability are studied. Fully separated as well as homogenous network morphologies are obtained depending on the ratio between acrylate and epoxy monomers, cure rate and applied light source (405 vs 365 nm). In general, glass transition temperature, stiffness, and tensile strength of the photopolymers increase with rising epoxy content. In contrast, a higher epoxy concentration in combination with a higher amount of the cationic photoinitiator compromises on the system's orthogonality, giving rise to the important role of the resin composition in dual-wavelength vat photopolymerization 3D printing. 相似文献
66.
Kate Orff 《Architectural Design》2020,90(1):94-99
Our era of ecological resilience and ecocide requires much more holistic and inclusive thinking about social, civic space. Kate Orff is a co-director of the Center for Resilient Cities at Columbia University Graduate School of Architecture, Planning and Preservation in New York, and founder of landscape and urban design practice SCAPE. Here she outlines the studio's proposal for Alameda Creek, which removes the defensive infrastructures currently restraining the natural forces of the San Francisco Bay Area with the aim of reconnecting its urban and rural ecologies. 相似文献
67.
Fiammetta Pagano;Jan Král;Kateřina Děcká;Marco Pizzichemi;Eva Mihóková;Václav Čuba;Etiennette Auffray; 《Advanced Materials Interfaces》2024,11(10):2300659
Time-of-flight (TOF) technique, traditionally used in high energy physics (HEP) and positron emission tomography (PET), is now being explored for lower energy applications like computed tomography (CT). Regardless of the application, pushing the current boundaries in time resolution calls for novel technologies and materials exhibiting ultra-fast time response. Semiconductor nanocrystals like cesium lead halide perovskites (CsPbBr3), benefiting from quantum confinement effects, feature ultra-fast decay and, when combined with a suitable bulk scintillator following a heterostructure concept, can also provide the necessary stopping power. In this work, thin films of CsPbBr3 on top of BGO, LYSO:Ce, and GAGG:Ce,Mg wafers are fabricated to test their impact on the single crystal scintillator time resolution under soft X-rays excitation (about 10 keV). It is demonstrated that the CsPbBr3 layer significantly improves the overall time resolution in all cases, achieving up to a tenfold improvement with BGO and GAGG:Ce,Mg. Under 511 keV γ-rays, a proof-of-concept of the heterostructure design for TOF-PET using CsPbBr3 thin film deposited on GAGG:Ce,Mg bulk crystal is successfully tested. Shared events depositing energy in both materials are identified, resulting in more than twofold improved coincidence time resolution: 118 ± 4 ps full-width-at-half-maximum (FWHM) compared to the 272 ± 8 ps of solely GAGG:Ce,Mg. 相似文献
68.
69.
My-Anh Doan Carmen I. Tobos Rachel L. Creighton Teri Guo Kate A. Faber Youngshang Han Cerwyn Chiew Ian T. Hull Mohammad H. Malakooti Kim A. Woodrow 《Advanced Engineering Materials》2023,25(17):2300670
Electrostatic patterning has improved the performance of devices incorporating electrospun fibers in a wide variety of applications. However, the impact of process parameters on the final fiber pattern in these systems is rarely analyzed. Herein, a systematic analytical approach is developed to define quantitative metrics related to fiber patterning. Three-dimensional patterned dielectric elastomer collectors are fabricated via solution-casting polydimethylsiloxane with embedded carbon black or liquid metal droplets. Fiber patterning metrics are used to evaluate the effect of collector parameters such as insulating layer thickness, electrical ground surface area, and three-dimensional pattern geometry. Dielectric layer parameters such as conductive material concentration and particle diameter are also investigated. Using this framework, the best-performing collector is shown to improve selectivity 30-fold, uniformity ninefold, reproducibility eightfold, and increase fiber volume by one order of magnitude. Furthermore, eutectic gallium indium liquid metal and scaled-up pattern geometries demonstrate the tunability of this approach and broad applicability of systematic fiber pattern analysis. This rational approach to patterned fiber development can be applied to virtually any method or pattern to better understand the fiber patterning processes. 相似文献
70.
Kierstin Torres Agnieszka Kuc Lorenzo Maschio Thang Pham Kate Reidy Lukas Dekanovsky Zdenek Sofer Frances M. Ross Julian Klein 《Advanced functional materials》2023,33(12):2211366
Understanding the stability limitations and defect formation mechanisms in 2D magnets is essential for their utilization in spintronic and memory technologies. Here, defects in mono- to multilayer CrSBr are correlated with structural, vibrational, and magnetic properties. Resonant Raman scattering is used to reveal distinct vibrational defect signatures. In pristine CrSBr, it is shown that bromine atoms mediate vibrational interlayer coupling, allowing for distinguishing between surface and bulk defect modes. Environmental exposure is shown to cause drastic degradation in monolayers, with the formation of intralayer defects. This is in contrast to multilayers that predominantly show bromine surface defects. Through deliberate ion irradiation, the formation of defect modes is tuned: these are strongly polarized and resonantly enhanced, reflecting the quasi--1D electronic character of CrSBr. Strikingly, pronounced signatures of spin-phonon coupling of the intrinsic phonon modes and the ion beam-induced defect modes are observed throughout the magnetic transition temperature. Overall, defect engineering of magnetic properties is possible, with resonant Raman spectroscopy serving as a direct fingerprint of magnetic phases and defects in CrSBr. 相似文献