全文获取类型
收费全文 | 782篇 |
免费 | 42篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 7篇 |
化学工业 | 203篇 |
金属工艺 | 7篇 |
机械仪表 | 6篇 |
建筑科学 | 36篇 |
能源动力 | 17篇 |
轻工业 | 107篇 |
水利工程 | 5篇 |
石油天然气 | 4篇 |
无线电 | 75篇 |
一般工业技术 | 96篇 |
冶金工业 | 27篇 |
原子能技术 | 4篇 |
自动化技术 | 233篇 |
出版年
2024年 | 1篇 |
2023年 | 11篇 |
2022年 | 34篇 |
2021年 | 36篇 |
2020年 | 28篇 |
2019年 | 16篇 |
2018年 | 19篇 |
2017年 | 25篇 |
2016年 | 23篇 |
2015年 | 26篇 |
2014年 | 42篇 |
2013年 | 62篇 |
2012年 | 55篇 |
2011年 | 56篇 |
2010年 | 55篇 |
2009年 | 55篇 |
2008年 | 59篇 |
2007年 | 40篇 |
2006年 | 30篇 |
2005年 | 17篇 |
2004年 | 15篇 |
2003年 | 18篇 |
2002年 | 19篇 |
2001年 | 6篇 |
2000年 | 12篇 |
1999年 | 9篇 |
1998年 | 8篇 |
1997年 | 7篇 |
1996年 | 4篇 |
1995年 | 5篇 |
1994年 | 9篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1991年 | 8篇 |
1990年 | 3篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有827条查询结果,搜索用时 15 毫秒
811.
Surface roughness has an important role in the performance of finished components. End ball milling is used for achieving high surface quality, especially in complex geometries. Depending on the cutting conditions selected for ball end milling, different milling strategies can be applied. The produced surface quality is greatly affected from the selected milling strategy. The present paper examines the influence of the milling strategy selection on the surface roughness of an Al7075-T6 alloy. A number of cutting parameters are tested (axial and radial depth of cut, feed rate, inclination angles φ and ω) in order to perform 96 experiments and their results are processed using regression analysis and analysis of variance. All possible milling strategies are considered (vertical, push, pull, oblique, oblique push and oblique pull) and for each one of them, a mathematical model of the surface roughness is established, considering both the down and up milling. All models are statistically validated and experimentally verified, and can be used within the limits of the investigating cutting conditions. The polynomials produced are of the third order and the statistically most significant parameters are presented. 相似文献
812.
Aleksandra Lekić Ben Hermans Nenad Jovičić Panagiotis Patrinos 《International Journal of Circuit Theory and Applications》2020,48(3):406-419
In this paper, we present a novel nonlinear model predictive control (NMPC) formulation for the transient control of a DC-DC converter. We demonstrate that a real-time implementation of the proposed NMPC scheme using the PANOC solver can be efficiently applied to control DC-DC converters in the microsecond range. Moreover, an embedded, code-generated version of PANOC can be implemented using microcontrollers or digital signal processors. The algorithm is incorporated in the transient simulator of PWM DC-DC converters, and the operation of the simulator on the boost converter's example is presented, comparing the performance of our NMPC-controller with that of a classical PID controller. The operation of the boost converter controlled using the proposed NMPC algorithm is validated experimentally. 相似文献
813.
Model-based control of particulate processes 总被引:1,自引:0,他引:1
Panagiotis D. Christofides Nael El-Farra Prashant Mhaskar 《Chemical engineering science》2008,63(5):1156-1172
In this work, we present an overview of recently developed methods for model-based control of particulate processes. We primarily discuss methods developed in the context of our previous research work and use examples of crystallization, aerosol and thermal spray processes to motivate the development of these methods and illustrate their application. Specifically, we initially discuss control methods for particulate processes which utilize suitable approximations of population balance models to design nonlinear, robust and predictive control systems and demonstrate their application to crystallization and aerosol processes. Finally, we discuss the issues of control problem formulation and controller design for high-velocity oxygen-fuel (HVOF) thermal spray processes and close with few thoughts on unresolved research challenges on control of particulate processes. 相似文献
814.
815.
Dimitra Dimitrellou Panagiotis Kandylis Athanasios Mallouchos Michalis Komaitis Athanasios A. Koutinas Yiannis Kourkoutas 《Food chemistry》2010
The effect of freeze–dried kefir culture on the proteolysis of feta-type and whey-cheese was investigated. All nitrogen fractions increased during ripening. Although no significant differences were observed in total nitrogen (TN), the levels of water-soluble nitrogen (WSN), pH 4.4-soluble nitrogen (SN), 12% trichloroacetic acid-soluble nitrogen (TCA-SN) and phosphotungstic acid-soluble nitrogen (PTA-SN) were significantly higher in cheeses produced by freeze–dried kefir culture during the later stages of ripening. Content of total free amino acids (FAA) was significantly affected by freeze–dried kefir starter culture and it was continuously increased in kefir-cheese while, in rennet-cheese it was increased up to 30 days of ripening and then slightly decreased. On the other hand, FAA content continuously decreased in kefir-whey-cheese whereas it increased in whey-cheese. The cheese samples produced by freeze–dried kefir as starter culture were characterised as high-quality products during the preliminary sensory evaluation and they were accepted by the panel. Overall, the use of freeze–dried kefir suggested acceleration of cheese ripening and resulted in improved sensory characteristics. 相似文献
816.
Poulopoulos P Kapaklis V Politis C Schweiss P Fuchs D 《Journal of nanoscience and nanotechnology》2006,6(12):3867-3870
Nanoscale Ni films in the thickness range 15-500 nm were grown on various substrates, such as amorphous glass, single crystalline silicon and sapphire, and polycrystalline alumina, at a temperature of about 350 K by radio frequency magnetron sputtering. It is demonstrated, via X-ray diffraction and high-resolution transmission electron microscopy, that there is an Ar-gas pressure window that favors the growth of stable single-phase hexagonal nanocrystalline Ni films regardless of the film thickness and the kind of the substrate. At lower or higher Ar pressures the films grow in the regular face centered cubic phase of Ni. The structural habits are attributed to differences in the kinetic energy of the Ni atoms impinging on the substrates. Superconducting quantum interference device magnetometry measurements reveal that the hexagonal films show zero magnetic response down to liquid Helium temperature. This result is discussed with respect to earlier first principle calculations and to experimental results on Ni nanoparticles. 相似文献
817.
Evaluation of monobasic calcium phosphate for the immobilization of heavy metals in contaminated soils from Lavrion 总被引:18,自引:0,他引:18
The objective of this work was to evaluate the efficiency of monobasic calcium phosphate for the stabilization of heavy metals in contaminated soils. The treatment was applied on a soil sample from the Lavrion mining area, Greece, heavily contaminated with Pb, Zn, Cd and As and characterized as toxic in respect to Pb according to the US EPA toxicity characteristics leaching procedure (TCLP). The efficiency of stabilization was evaluated based on two criteria: (a) the reduction of metals mobility below the TCLP regulatory limits; (b) the reduction of phytoaccumulation. Phytoaccumulation was evaluated both indirectly by applying leaching tests using EDTA, DTPA and NaHCO(3) solutions and directly by carrying out pot experiments with Phaseolus vulgaris as plant indicator. This treatment was found to immobilize Pb and Cd, whereas As and Zn were slightly mobilized. No effect on phytoaccumulation was observed. Moreover, the treatment had a negative effect on plants growth, which was combined with a strong deficiency of Ca in the tissue of leaves. 相似文献
818.
Panagiotis Zagaliotis Anthi Petrou George A. Mystridis Athina Geronikaki Ioannis S. Vizirianakis Thomas J. Walsh 《International journal of molecular sciences》2022,23(14)
Broad-spectrum antiviral agents that are effective against many viruses are difficult to develop, as the key molecules, as well as the biochemical pathways by which they cause infection, differ largely from one virus to another. This was more strongly highlighted by the COVID-19 pandemic, which found health systems all over the world largely unprepared and proved that the existing armamentarium of antiviral agents is not sufficient to address viral threats with pandemic potential. The clinical protocols for the treatment of COVID-19 are currently based on the use of inhibitors of the inflammatory cascade (dexamethasone, baricitinib), or inhibitors of the cytopathic effect of the virus (monoclonal antibodies, molnupiravir or nirmatrelvir/ritonavir), using different agents. There is a critical need for an expanded armamentarium of orally bioavailable small-molecular medicinal agents, including those that possess dual antiviral and anti-inflammatory (AAI) activity that would be readily available for the early treatment of mild to moderate COVID-19 in high-risk patients. A multidisciplinary approach that involves the use of in silico screening tools to identify potential drug targets of an emerging pathogen, as well as in vitro and in vivo models for the determination of a candidate drug’s efficacy and safety, are necessary for the rapid and successful development of antiviral agents with potentially dual AAI activity. Characterization of candidate AAI molecules with physiologically based pharmacokinetics (PBPK) modeling would provide critical data for the accurate dosing of new therapeutic agents against COVID-19. This review analyzes the dual mechanisms of AAI agents with potential anti-SARS-CoV-2 activity and discusses the principles of PBPK modeling as a conceptual guide to develop new pharmacological modalities for the treatment of COVID-19. 相似文献
819.
Christos Damaskos Nikolaos Garmpis Dimitrios Dimitroulis Anna Garmpi Iason Psilopatis Panagiotis Sarantis Evangelos Koustas Prodromos Kanavidis Dionysios Prevezanos Gregory Kouraklis Michail V. Karamouzis Georgios Marinos Konstantinos Kontzoglou Efstathios A. Antoniou 《International journal of molecular sciences》2022,23(22)
Hepatocellular carcinoma (HCC) remains one of the most common malignancies and the third cause of cancer-related death worldwide, with surgery being the best prognostic tool. Among the well-known causative factors of HCC are chronic liver virus infections, chronic virus hepatitis B (HBV) and chronic hepatitis virus C (HCV), aflatoxins, tobacco consumption, and non-alcoholic liver disease (NAFLD). There is a need for the development of efficient molecular markers and alternative therapeutic targets of great significance. In this review, we describe the general characteristics of HCC and present a variety of targeted therapies that resulted in progress in HCC therapy. 相似文献
820.
Grontas Panagiotis Pagourtzis Aris 《International Journal of Information Security》2023,22(4):819-832
International Journal of Information Security - Everlasting privacy protects cryptographic voting systems against the weakening of intractability assumptions on which they may be based. We find... 相似文献