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81.
The master-alloy ingots for casting bulk metallic glasses are routinely prepared by arc melting a mixture of pure elements. This paper addresses the difficulty in achieving complete and homogeneous melting of refractory component additions in Zr-based BMGs using the above procedure, and its influences on the microstructure and thermal behavior of alloys. 相似文献
82.
Annica Prhl Milijana Batinic Said Alkildani Michael Hahn Milena Radenkovic Stevo Najman Ole Jung Mike Barbeck 《International journal of molecular sciences》2021,22(9)
The present in vivo study analyses both the inflammatory tissue reactions and the bone healing capacity of a newly developed bone substitute material (BSM) based on xenogeneic bone substitute granules combined with hyaluronate (HY) as a water-binding molecule. The results of the hyaluronate containing bone substitute material (BSM) were compared to a control xenogeneic BSM of the same chemical composition and a sham operation group up to 16 weeks post implantationem. A major focus of the study was to analyze the residual hyaluronate and its effects on the material-dependent healing behavior and the inflammatory tissue responses. The study included 63 male Wistar rats using the calvaria implantation model for 2, 8, and 16 weeks post implantationem. Established and Good Laboratory Practice (GLP)-conforming histological, histopathological, and histomorphometrical analysis methods were conducted. The results showed that the new hyaluronate containing BSM was gradually integrated within newly formed bone up to the end of the study that ended in a condition of complete bone defect healing. Thereby, no differences to the healing capacity of the control BSM were found. However, the bone formation in both groups was continuously significantly higher compared to the sham operation group. Additionally, no differences in the (inflammatory) tissue response that was analyzed via qualitative and (semi-) quantitative methods were found. Interestingly, no differences were found between the numbers of pro- and anti-inflammatory macrophages between the three study groups over the entire course of the study. No signs of the HY as a water-binding part of the BSM were histologically detectable at any of the study time points, altogether the results of the present study show that HY allows for an optimal material-associated bone tissue healing comparable to the control xenogeneic BSM. The added HY seems to be degraded within a very short time period of less than 2 weeks so that the remaining BSM granules allow for a gradual osteoconductive bone regeneration. Additionally, no differences between the inflammatory tissue reactions in both material groups and the sham operation group were found. Thus, the new hyaluronate containing xenogeneic BSM and also the control BSM have been shown to be fully biocompatible without any differences regarding bone regeneration. 相似文献
83.
Improved production of ginsenosides in suspension cultures of ginseng by medium replenishment strategy 总被引:1,自引:0,他引:1
The objective of this study was to improve the accumulation of ginsenosides by the adventitious root cultures of ginseng, which are important secondary metabolites with pharmaceutical applications. The adventitious roots were cultured in bioreactors for 50 d using 1.5-strength Murashige and Skoog (MS) medium supplemented with 10 mg/l indole acetic acid and 75 g/l sucrose. Kinetic studies of the nutrient composition of the spent medium revealed the gradual depletion of various inorganic nutrients and sugars. Cultures were supplied with fresh nutrient medium (medium exchange or replenishment with 0.75- and 1.0-strength MS medium) after 10 and 20 d of culture initiation to fulfill the nutritional requirements of adventitious roots. Medium replenishment strategy (with 1.0-strength MS medium after 20 d of culture) significantly improved the growth of adventitious roots and the biosynthesis of ginsenosides by the adventitious roots. This work is useful for the large-scale cultivation of adventitious roots for the production of ginsenosides. 相似文献
84.
J.-M. Yoon M.-H. Cho J.-E. Park Y.-H. Kim T.-R. Hahn Y.-S. Paik 《Journal of food science》2003,68(3):839-843
ABSTRACT Three major yellow pigments were isolated from safflower petals ( Carthamus tinctorius ) and characterized as hydroxysafflor yellow A (1), safflor yellow B (2), and precarthamin (3) by 1 H-NMR, 1 H-1 H COSY, 13 C-NMR, HMQC, and HMBC spectral analysis. Thermal degradation reactions of 3 yellow pigments 1 to 3 at temperatures of 70 to 90 °C were carried out at different pH levels within the range of 3.0 to 10.0 by UV-vis spectral measurements. First-order reaction kinetics was observed for the degradation of safflower yellow pigments (1 to 3) at pH 3.0 and 5.0. Activation energies of thermal degradation of 1-3 at pH 5.0 were calculated as 17.0, 15.4, and 20.1 kcal/mol, respectively. At neutral and alkaline conditions, yellow pigments 1-3 did not follow simple first-order kinetics. 相似文献
85.
A Nonlinear Structure Tensor with the Diffusivity Matrix Composed of the Image Gradient 总被引:1,自引:0,他引:1
We propose a nonlinear partial differential equation (PDE) for regularizing a tensor which contains the first derivative information
of an image such as strength of edges and a direction of the gradient of the image. Unlike a typical diffusivity matrix which
consists of derivatives of a tensor data, we propose a diffusivity matrix which consists of the tensor data itself, i.e., derivatives of an image. This allows directional smoothing for the tensor along edges which are not in the tensor but in
the image. That is, a tensor in the proposed PDE is diffused fast along edges of an image but slowly across them. Since we
have a regularized tensor which properly represents the first derivative information of an image, the tensor is useful to
improve the quality of image denoising, image enhancement, corner detection, and ramp preserving denoising. We also prove
the uniqueness and existence of solution to the proposed PDE. 相似文献
86.
There is typically a high degree of flexibility associated with the production of alternative fuels due to the ability to source from different input raw materials or to produce different output products based on market conditions. In this paper, we consider the particular example of ethanol and seek to quantify the incremental value from flexibility in its production from sugarcane in Brazil. We accomplish this by first jointly modeling the stochastic processes for the prices of the two relevant commodities, sugar (a food commodity) and ethanol (an energy commodity) in discrete time as a bivariate lattice. This framework allows us to value the option to switch output products based on the respective price signals of the two commodities. However, unlike the usual assumption of geometric Brownian motion stochastic processes, we use the more realistic case of mean reverting commodity price processes. We estimate the parameters for these processes by applying a regression-based procedure to empirical sugar and ethanol data collected during a period from 1998 through 2008. Our results show that the option to switch outputs has significant value, even under the assumption of mean reverting prices, which has implications for both producers and policy-makers alike. 相似文献
87.
M. Hahn 《Forschung im Ingenieurwesen》2009,73(2):77-86
For the consideration of released mass flows and their effects within hazard studies, leakage areas need to be determined which are physically justifiable and which cannot be reasonably excluded. Applying the fracture mechanics the leak-before-break behaviour is verified by the calculation of the propagation of an initial material defect. Consequently, leakage areas of through-cracks are calculated to determine probable and maximum leakage areas. For this purpose, models for the calculation of leak sizes are compared and evaluated. Example calculations are stated for typical pressurised vessels and pipes of the chemical industry in order to check the present estimates of leakage areas. In addition, measures supporting the leak-before-break behaviour are outlined. 相似文献
88.
A. Hahn 《e & i Elektrotechnik und Informationstechnik》2002,119(10):a6-a6
AktuellDivitec Metal
Aufbereitung von Elektro(nik)-Altger?ten 相似文献89.
Most large-scale process models derived from first principles are represented by nonlinear differential–algebraic equation (DAE) systems. Since such models are often computationally too expensive for real-time control, techniques for model reduction of these systems need to be investigated. However, models of DAE type have received little attention in the literature on nonlinear model reduction. In order to address this, a new technique for reducing nonlinear DAE systems is presented in this work. This method reduces the order of the differential equations as well as the number and complexity of the algebraic equations. Additionally, the algebraic equations of the resulting system can be replaced by an explicit expression for the algebraic variables such as a feedforward neural network. This last property is important insofar as the reduced model does not require a DAE solver for its solution but system trajectories can instead be computed with regular ODE solvers. This technique is illustrated with a case study where responses of several different reduced-order models of a distillation column with 32 differential equations and 32 algebraic equations are compared. 相似文献
90.
Youlee Pae Keun‐Joo Lee Jaehwan Lee Sook‐Young Choi Seong‐Jae Hong Mi‐Sun Ryu Young‐Keun Kim Tae Yong Kim Bum‐Young Choi Chun‐Woo Yoo Yong‐Man Jung Hyuk‐Jin Cha Young Jun Kim Jun‐Hee Hahn 《Journal of the Society for Information Display》2002,10(4):339-342
A new series of photospacers has been prepared with different types of crosslinkers to improve elastic recovery. Afunctional crosslinker with six reactive groups demonstrates the best elastic recovery. As the quantity of crosslinker is increased, the elastic recovery also increases, probably due to an increase in the crosslinking density. The use of ADMS EPS® results in high resolution, good uniformity, and high production yield in the liquid‐crystal‐display (LCD) process. Especially, EPS® improves and solves problems such as viewing angle, crosstalk, and dark spots. 相似文献