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排序方式: 共有1402条查询结果,搜索用时 15 毫秒
21.
Tomasz Idziaszek Michał Skrzypczak Mikołaj Bojańczyk 《Theory of Computing Systems》2016,58(4):614-663
An infinite tree is called thin if it contains only countably many infinite branches. Thin trees can be seen as intermediate structures between infinite words and infinite trees. In this work we investigate properties of regular languages of thin trees. Our main tool is an algebra suitable for thin trees. Using this framework we characterize various classes of regular languages: commutative, open in the standard topology, and definable in weak MSO logic among all trees. We also show that in various meanings thin trees are not as rich as all infinite trees. In particular we observe a collapse of the parity index to the level (1, 3) and a collapse of the topological complexity to co-analytic sets. Moreover, a gap property is shown: a regular language of thin trees is either weak MSO-definable among all trees or co-analytic-complete. 相似文献
22.
A common way of computing all efficient (Pareto optimal) solutions for a biobjective combinatorial optimisation problem is to compute first the extreme efficient solutions and then the remaining, non-extreme solutions. The second phase, the computation of non-extreme solutions, can be based on a “k-best” algorithm for the single-objective version of the problem or on the branch-and-bound method. A k-best algorithm computes the k-best solutions in order of their objective values. We compare the performance of these two approaches applied to the biobjective minimum spanning tree problem. Our extensive computational experiments indicate the overwhelming superiority of the k-best approach. We propose heuristic enhancements to this approach which further improve its performance. 相似文献
23.
Zeyad A. Almutairi Tomasz Glawdel Carolyn L. Ren David A. Johnson 《Microfluidics and nanofluidics》2009,6(2):241-251
This study presents a new Y-channel design for measuring the zeta potential and surface conductance of a solid-liquid pairing
using the current monitoring technique. The new design improves the throughput and reliability of the testing apparatus since
the displacement between two solutions can be repeated many times without interfering with the experiments. It also increases
the accuracy of the measurement by producing sharper start and end transitions for the current–time plot of the solution displacement
process. In this design, efforts have been made to minimize the effects of electrolysis, Joule heating and undesired pressure
driven flow on the measurements. An improvement on the current–time slope analysis is also presented. The Y-channel design
was validated by comparing zeta potential measurements to published results. The zeta potential of several biological buffers
relevant to the microfluidic community in plasma treated PDMS/PDMS and PDMS/Glass microchannels are presented. Preliminary
studies of surface conductivity measurements using the Y-channel design were also conducted and are briefly discussed. 相似文献
24.
25.
Sādhanā - This paper presents the results of experimental research of the phenomena occurring in water ram during a single cycle of its operation. Apart from a brief introduction and... 相似文献
26.
Transistors: Impact of Interfacial Microstructure on Charge Carrier Transport in Solution‐Processed Conjugated Polymer Field‐Effect Transistors (Adv. Mater. 11/2016) 下载免费PDF全文
27.
Modeling spatially distributed phenomena in terms of its controlling factors is a recurring problem in geoscience. Most efforts
concentrate on predicting the value of response variable in terms of controlling variables either through a physical model
or a regression model. However, many geospatial systems comprises complex, nonlinear, and spatially non-uniform relationships,
making it difficult to even formulate a viable model. This paper focuses on spatial partitioning of controlling variables
that are attributed to a particular range of a response variable. Thus, the presented method surveys spatially distributed
relationships between predictors and response. The method is based on association analysis technique of identifying emerging
patterns, which are extended in order to be applied more effectively to geospatial data sets. The outcome of the method is
a list of spatial footprints, each characterized by a unique “controlling pattern”—a list of specific values of predictors
that locally correlate with a specified value of response variable. Mapping the controlling footprints reveals geographic
regionalization of relationship between predictors and response. The data mining underpinnings of the method are given and
its application to a real world problem is demonstrated using an expository example focusing on determining variety of environmental
associations of high vegetation density across the continental United States. 相似文献
28.
Cezary Graczykowski Tomasz Lewiński 《Structural and Multidisciplinary Optimization》2010,42(6):869-877
The paper delivers the benchmark results for the Michell cantilevers constructed within a half strip, for selected values
of the σ
T
/σ
C
ratio, σ
T
, σ
C
being the admissible stresses in tension and compression, respectively. 相似文献
29.
Tomasz Fałat Kazimierz Friedel Norman Marenco Stephan Warnat 《Microsystem Technologies》2009,15(1):181-190
The current paper focuses on several mechanical aspects of a waferlevel packaging approach using a direct face-to-face Chip-to-Wafer
(C2W) bonding of a MEMS device on an ASIC substrate wafer. Requirements of minimized inherent stress from packaging and good
decoupling from forces applied in manufacturing and application are discussed with particular attention to the presence of
through-silicon vias (TSV) in the substrate wafer. The paper deals with FEM analysis of temperature excursion, pressure during
molding, materials used and handling load influence on mechanical stress within the TSV system and on wafer level, which can
be large enough to disintegrate the system. 相似文献
30.