全文获取类型
收费全文 | 423篇 |
免费 | 14篇 |
专业分类
化学工业 | 71篇 |
金属工艺 | 3篇 |
机械仪表 | 4篇 |
建筑科学 | 9篇 |
能源动力 | 14篇 |
轻工业 | 21篇 |
水利工程 | 6篇 |
无线电 | 45篇 |
一般工业技术 | 89篇 |
冶金工业 | 46篇 |
自动化技术 | 129篇 |
出版年
2023年 | 2篇 |
2022年 | 6篇 |
2021年 | 7篇 |
2020年 | 2篇 |
2019年 | 6篇 |
2018年 | 6篇 |
2017年 | 7篇 |
2016年 | 11篇 |
2015年 | 12篇 |
2014年 | 12篇 |
2013年 | 18篇 |
2012年 | 24篇 |
2011年 | 22篇 |
2010年 | 16篇 |
2009年 | 22篇 |
2008年 | 24篇 |
2007年 | 21篇 |
2006年 | 27篇 |
2005年 | 15篇 |
2004年 | 14篇 |
2003年 | 9篇 |
2002年 | 13篇 |
2001年 | 4篇 |
2000年 | 4篇 |
1999年 | 8篇 |
1998年 | 11篇 |
1997年 | 20篇 |
1996年 | 12篇 |
1995年 | 5篇 |
1994年 | 5篇 |
1993年 | 6篇 |
1992年 | 9篇 |
1991年 | 2篇 |
1989年 | 2篇 |
1987年 | 4篇 |
1985年 | 8篇 |
1984年 | 3篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1979年 | 2篇 |
1977年 | 6篇 |
1976年 | 4篇 |
1975年 | 3篇 |
1971年 | 1篇 |
1970年 | 2篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1967年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有437条查询结果,搜索用时 15 毫秒
1.
D Sternberg A Peled E Shezen O Abramsky W Jiang F Bertolero D Zipori 《Canadian Metallurgical Quarterly》1996,2(1):29-38
The immunological agglutination reactions of physically absorbed F(ab')2 molecules onto anionic and cationic latex particles have been investigated by means of optical absorbance measurements. These measurements have been conducted under different conditions to determine the most influential factors. Surface F(ab')2 and BSA densities, particle concentration in the reaction medium and polyethylene glycol concentration are some of these factors. Sensitized cationic and anionic latexes differ considerably with respect to their colloidal stability and reactivity. As a general rule, the sensitized cationic latex has a relatively higher colloidal stability and hence, it provides reagents with a better optical response. Less than 0.025 microgram/ml of C-reactive protein has been detected using this particle enhanced optical immunoassay. 相似文献
2.
We consider the problem of scheduling jobs on related machines owned by selfish agents. We provide a 5-approximation deterministic
truthful mechanism, the first deterministic truthful result for the problem. Previously, Archer and Tardos showed a 2-approximation
randomized mechanism which is truthful in expectation only (a weaker notion of truthfulness). In case the number of machines
is constant, we provide a deterministic Fully Polynomial-Time Approximation Scheme (FPTAS) and a suitable payment scheme that
yields a truthful mechanism for the problem. This result, which is based on converting FPTAS to monotone FPTAS, improves a
previous result of Auletta et al., who showed a (4 + ε)-approximation truthful mechanism. 相似文献
3.
4.
The design of specialized processing array architectures, capable of executing any given arbitrary algorithm, is proposed. An approach is adopted in which the algorithm is first represented in the form of a dataflow graph and then mapped onto the specialized processor array. The processors in this array execute the operations included in the corresponding nodes (or subsets of nodes) of the dataflow graph, while regular interconnections of these elements serve as edges of the graph. To speed up the execution, the proposed array allows the generation of computation fronts and their cancellation at a later time, depending on the arriving data operands; thus it is called a data-driven array. The structure of the basic cell and its programming are examined. Some design details are presented for two selected blocks, the instruction memory and the flag array. A scheme for mapping a dataflow graph (program) onto a hexagonally connected array is described and analyzed. Two distinct performance measures-mapping efficiency and array utilization-and some performance results are discussed 相似文献
5.
Multiresolution is currently one of the main schemes used in CAD modeling for representing objects, particularly when large-scale geometric data must be transferred interactively over a network, as in the case of collaborative design. Increasingly complex products and growing competition have turned design into a collaborative team effort. Furthermore, the widespread development of Internet viewers has also necessitated the transfer and display of large-scale CAD models over networks. In order to reduce the volume of transferred data, efforts have been made to transfer CSG (Constructive Solid Geometry) models rather than those based on B_rep (Boundary Representation). This paper presents an original new method for speeding up data transfer by using multiresolution CSG models at different levels of details (LOD). The multiresolution CSG algorithm generates a hierarchy of multiresolution CSG trees; at each level, the shape is further approximated and represented by a smaller number of CSG primitives. The paper analyzes the proposed algorithm, and demonstrates its feasibility. 相似文献
6.
Dan Raviv Alexander M. Bronstein Michael M. Bronstein Dan Waisman Nir Sochen Ron Kimmel 《Journal of Mathematical Imaging and Vision》2014,50(1-2):144-163
Traditional models of bendable surfaces are based on the exact or approximate invariance to deformations that do not tear or stretch the shape, leaving intact an intrinsic geometry associated with it. These geometries are typically defined using either the shortest path length (geodesic distance), or properties of heat diffusion (diffusion distance) on the surface. Both measures are implicitly derived from the metric induced by the ambient Euclidean space. In this paper, we depart from this restrictive assumption by observing that a different choice of the metric results in a richer set of geometric invariants. We apply equi-affine geometry for analyzing arbitrary shapes with positive Gaussian curvature. The potential of the proposed framework is explored in a range of applications such as shape matching and retrieval, symmetry detection, and computation of Voroni tessellation. We show that in some shape analysis tasks, equi-affine-invariant intrinsic geometries often outperform their Euclidean-based counterparts. We further explore the potential of this metric in facial anthropometry of newborns. We show that intrinsic properties of this homogeneous group are better captured using the equi-affine metric. 相似文献
7.
Small‐angle X‐ray scattering (SAXS) was applied to investigate the microstructure of unmodified and modified porous commercial suspension‐type poly(vinyl chloride) (PVC) particles. The modified PVC particles were prepared by an in situ stabilizer‐free polymerization/crosslinking of particles absorbed with a monomer/crosslinker/peroxide solution. The modifying polymers include styrene with or without divinyl benzene (DVB) as a crosslinker and methyl methacrylate (MMA) with or without ethylene glycol dimethacrylate (EGDMA) as a crosslinker. The SAXS method was used to highlight the effect of polystyrene (PS) on the microstructure of PVC particles and to evaluate the characteristic lengths, both in the PVC/PS and the PVC/XPS (PS crosslinked with 0 and 5% DVB, respectively) systems. A model is suggested, where during the synthesis modification process, swelling of PVC by styrene and styrene polymerization occur simultaneously. PVC swelling by styrene causes destruction of the PVC subprimary particles, whereas styrene polymerization leads to phase separation resulting from incompatibility of the polymers. It was further suggested that because of PVC swelling by styrene, structure of the subprimary particles is lost. Therefore the characteristic lengths of PVC/PS and PVC/XPS, as calculated from the SAXS measurements, were attributed to the size of the phase‐separated PS and XPS inclusions, respectively. The SAXS method also shows that PMMA and XPMMA do not influence the PVC microstructure. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1024–1031, 2005 相似文献
8.
Difficulties in integrating technical, economic and institutional factors present a major gap in analytical capacity to guide water policy. This article presents an integrated framework to support water policy and guide water management choices, with application to Israel. That framework rests on the theory of economic policy originally developed by Tinbergen. It sees national water challenges as consisting of external factors, constraints, policy instruments and targets. The need for a modern implementation of the theory of economic policy is motivated by emerging environmental requirements, scarce water, growing demands for domestic use, and ongoing needs to implement existing and potential peace agreements. 相似文献
9.
Tal Nir Alfred M. Bruckstein Ron Kimmel 《International Journal of Computer Vision》2008,76(2):205-216
A novel optical flow estimation process based on a spatio-temporal model with varying coefficients multiplying a set of basis
functions at each pixel is introduced. Previous optical flow estimation methodologies did not use such an over parameterized
representation of the flow field as the problem is ill-posed even without introducing any additional parameters: Neighborhood
based methods of the Lucas–Kanade type determine the flow at each pixel by constraining the flow to be described by a few
parameters in small neighborhoods. Modern variational methods represent the optic flow directly via the flow field components
at each pixel. The benefit of over-parametrization becomes evident in the smoothness term, which instead of directly penalizing
for changes in the optic flow, accumulates a cost of deviating from the assumed optic flow model. Our proposed method is very
general and the classical variational optical flow techniques are special cases of it, when used in conjunction with constant
basis functions. Experimental results with the novel flow estimation process yield significant improvements with respect to
the best results published so far. 相似文献
10.
Study of DNA Origami Dimerization and Dimer Dissociation Dynamics and of the Factors that Limit Dimerization
下载免费PDF全文
![点击此处可从《Small (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Miran Liber Toma E. Tomov Roman Tsukanov Yaron Berger Mary Popov Dinesh C. Khara Eyal Nir 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(23)
Organizing DNA origami building blocks into higher order structures is essential for fabrication of large structurally and functionally diverse devices and molecular machines. Unfortunately, the yields of origami building block attachment reactions are typically not sufficient to allow programed assembly of DNA devices made from more than a few origami building blocks. To investigate possible reasons for these low yields, a detailed single‐molecule fluorescence study of the dynamics of rectangular origami dimerization and origami dimer dissociation reactions is conducted. Reactions kinetics and yields are investigated at different origami and ion concentrations, for different ion types, for different lengths of bridging strands, and for the “sticky end” and “weaving welding” attachment techniques. Dimerization yields are never higher than 86%, which is typical for such systems. Analysis of the dynamic data shows that the low yield cannot be explained by thermodynamic instability or structural imperfections of the origami constructs. Atomic force microscopy and gel electrophoresis evidence reveal self‐dimerization of the origami monomers, likely via blunt‐end interactions made possible by the presence of bridging strands. It is suggested that this mechanism is the major factor that inhibits correct dimerization and means to overcome it are discussed. 相似文献