全文获取类型
收费全文 | 191篇 |
免费 | 10篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 45篇 |
金属工艺 | 14篇 |
机械仪表 | 2篇 |
建筑科学 | 16篇 |
能源动力 | 6篇 |
轻工业 | 23篇 |
水利工程 | 5篇 |
无线电 | 20篇 |
一般工业技术 | 18篇 |
冶金工业 | 20篇 |
自动化技术 | 29篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 4篇 |
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 2篇 |
2018年 | 3篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 2篇 |
2014年 | 11篇 |
2013年 | 9篇 |
2012年 | 5篇 |
2011年 | 11篇 |
2010年 | 6篇 |
2009年 | 12篇 |
2008年 | 7篇 |
2007年 | 11篇 |
2006年 | 13篇 |
2005年 | 9篇 |
2004年 | 5篇 |
2003年 | 6篇 |
2002年 | 3篇 |
2001年 | 4篇 |
2000年 | 2篇 |
1999年 | 5篇 |
1998年 | 11篇 |
1997年 | 3篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1975年 | 2篇 |
1973年 | 2篇 |
1972年 | 1篇 |
排序方式: 共有201条查询结果,搜索用时 0 毫秒
51.
Evidence for Novel Action at the Cell‐Binding Site of Human Angiogenin Revealed by Heteronuclear NMR Spectroscopy,in silico and in vivo Studies 下载免费PDF全文
Dr. Demetra S. M. Chatzileontiadou Aikaterini C. Tsika Dr. Zoi Diamantopoulou Prof. Jean Delbé Prof. Josette Badet Prof. José Courty Dr. Vassiliki T. Skamnaki Dr. Vanessa Parmenopoulou Prof. Dimitri Komiotis Dr. Joseph M. Hayes Prof. Georgios A. Spyroulias Prof. Demetres D. Leonidas 《ChemMedChem》2018,13(3):259-269
A member of the ribonuclease A superfamily, human angiogenin (hAng) is a potent angiogenic factor. Heteronuclear NMR spectroscopy combined with induced‐fit docking revealed a dual binding mode for the most antiangiogenic compound of a series of ribofuranosyl pyrimidine nucleosides that strongly inhibit hAng's angiogenic activity in vivo. While modeling suggests the potential for simultaneous binding of the inhibitors at the active and cell‐binding sites, NMR studies indicate greater affinity for the cell‐binding site than for the active site. Additionally, molecular dynamics simulations at 100 ns confirmed the stability of binding at the cell‐binding site with the predicted protein–ligand interactions, in excellent agreement with the NMR data. This is the first time that a nucleoside inhibitor is reported to completely inhibit the angiogenic activity of hAng in vivo by exerting dual inhibitory activity on hAng, blocking both the entrance of hAng into the cell and its ribonucleolytic activity. 相似文献
52.
Experiments have been performed on a Fourdrinier pilot paper machine to characterize the behaviour of a Polyethylene Oxide (PEO) and Cofactor (CF) retention aid system under slow wire speed and very low shear conditions. Three wet‐end variables (PEO state of entanglement, PEO dosage and CF to PEO ratio) have been manipulated and the dynamic variations of whitewater consistency have been recorded. The identification of the dynamics shows that the three variables affect the whitewater consistency significantly. A semi‐empirical model based on mass balances has shown that the time constants of the system are determined by the mixing dynamics of the chemicals prior to the wire and by the whitewater recirculation loop dynamics. These findings have been confirmed by a dynamic simulation of the wet‐end section of the paper machine, which could be used to design advanced control strategies of this critical papermaking step. 相似文献
53.
O. Hérès H. Dubos T. A. Girard P. Perrier D. Limagne J. P. Torre G. Waysand 《Journal of Low Temperature Physics》1993,93(3-4):449-454
We report a preliminary analysis of the irradiation of a suspension of superheated superconducting grains by55Fe at temperatures below 400 mK. The suspension comprised both Sn (20–25 micron) and Al (20 micron) grains in equal filling factors of 20%. The differential magnetic field sweep spectra exhibit a peak structure, which we discuss in terms of the absorption of the 6 keV Xray of the55Fe decay and secondary excitations. 相似文献
54.
Pascal Cougnon Denis Dochain Martin Guay Michel Perrier 《Journal of Process Control》2011,21(10):1526-1532
In this paper, we present an adaptive extremum seeking control scheme for fed-batch bioreactors with Haldane kinetics. The proposed adaptive extremum seeking approach utilizes the structure information of the process kinetics to derive a seeking algorithm that drives the system states to the desired setpoints that maximize the biomass production. It assumes that only the substrate concentration is available for on-line measurement. Lyapunov stability is used in the design of the extremum seeking controller structure and the development of the parameter learning laws. The performance of the approach is illustrated via numerical simulations. 相似文献
55.
Evapotranspiration: Concepts and Future Trends 总被引:1,自引:0,他引:1
Luis S. Pereira Alain Perrier Richard G. Allen Isabel Alves 《Canadian Metallurgical Quarterly》1999,125(2):45-51
Past research on evapotranspiration has provided sound theoretical knowledge and practical applications that have been validated through field measurements. Many different approaches have been used; however, when primary concepts and standard definitions are accepted, it is possible to find reasonable agreement among methods. This paper reviews such approaches, from Penman to Penman-Monteith. The standard concepts of potential evaporation (EP) and equilibrium evaporation (Ee), and the introduction of the climatic resistance (re), provide a better understanding of the role of the climate together with surface and aerodynamic resistances (rs and ra). Therefore, the concept of reference evapotranspiration (ETo), particularly the new one adopted by the Food and Agricultural Organization of the United Nations, can be better understood, as well as its limitations. Crop evapotranspiration (ETc) is related to both ETo and Ee. Crop coefficients (Kc) can be shown to have two components, αo and αc, with Kc = αoαc. The αo is a function of the climatic resistance and of the aerodynamic resistances of the crop and of the reference crop. The αc is a function of both surface and aerodynamic resistances of the crop and of the reference crop. From this analysis some ideas on future developments result that are directed toward providing compatibility between the one- and two-step calculation of ETc. 相似文献
56.
In this paper the dielectric strength, Electrostatic Charging Tendency (ECT), ageing stability, gassing tendency, heat transfer efficiency and stray gassing issue of mineral and silicone oils, synthetic and natural esters are analyzed and discussed. 相似文献
57.
In the skin, heparin, heparan sulphate and heparan sulphate proteoglycans control the storage and release of growth factors and protect them from early degradation. We developed a cosmetic active ingredient containing Hibiscus Abelmoschus seed extract (trade name Linefactor™) that can maintain the FGF-2 content in the skin by mimicking the protective effect of heparan sulphate proteoglycans. By preventing the natural degradation of FGF-2, Hibiscus Abelmoschus s eed extract maintains the bioavailability of this growth factor for its target cells, i.e. skin fibroblasts. Our in vitro evaluations showed that this ingredient exhibited heparan sulphate-like properties and dose-dependently protected FGF-2 from thermal degradation. We could also show that, in turn, the protected FGF-2 could stimulate the synthesis of sulphated GAGs, the natural protective molecules for FGF-2, thus providing a double protection. Finally, the in vitro results were confirmed in vivo thanks to a clinical study in which skin biomechanical properties and reduction in wrinkles were assessed. 相似文献
58.
In this paper, we pose and solve an adaptive extremum control problem to optimize the productivity of a van de Vusse reaction taking place in a tubular reactor governed by a set of nonlinear hyperbolic partial differential equations. Estimation and control algorithms that take into account control input constraints are developed by using a Lyapunov-based procedure, ensuring stability and convergence under a persistency of excitation condition. Here, we assume that the temperature information along the reactor is the only available on-line measurement to estimate the unmeasured objective function at the reactor exit. Numerical application of the proposed method shows that the resulting feedback algorithm steers the system to its optimum using a non-distributed jacket temperature actuation. The time evolution of the cost function is compared with an idealized distributed version of the algorithm presented previously. 相似文献
59.
A cobalt-based Phynox alloy was oxidized in the 800–1,100 °C temperature range. The alloy oxidation was consistent with a growth mechanism limited by the diffusion process in a growing Cr2O3 oxide scale. Water vapour enhanced the alloy oxidation rate and scale porosity. Thermal cycling tests at 900 and 1,000 °C showed that water vapour reduces the outer Mn1.5Cr1.5O4 subscale adherence, but the chromia scale adherence was not affected. These temperatures permited a rapid chromium supply from the substrate to form a continuous chromia scale. At 1,100 °C thermal cycling conditions led to scale spallation and chromium depletion in the alloy. In dry air, weight losses were recorded due to cobalt and molybdenum oxidation, giving CoCr2O4 and CoMoO4. In wet air, the initial porous chromia scale permited nickel and cobalt oxidation, leading to Ni5Co3O8 and CoCr2O4 formation and resulting in bad adherence during thermal cycling. 相似文献
60.
A controllability analysis of a paper machine forming zone in a newsprint mill was performed to determine the maximum allowable variability of the pulp furnished to the process. The goal was to keep the output variables, basis weight and first-pass retention between certain limits in spite of disturbances and paper grade changes. The results indicate that the process is more disturbed at high frequencies, and that the two output variables may be maintained within the interval ±1% of their nominal values if the maximum variability in the consistency and fines content of the thick-stock is kept lower than ±1 and ±2%, respectively. 相似文献