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排序方式: 共有3326条查询结果,搜索用时 171 毫秒
61.
Classification of Text Documents 总被引:14,自引:0,他引:14
62.
PVC-Based 2,2,2-Cryptand Sensor for Zinc Ions 总被引:1,自引:0,他引:1
A PVC-based membrane of 2,2,2-cryptand exhibits a very good response for Zn(2+) in a wide concentration range (from 2.06 ppm to 6.54 × 10(3) ppm) with a slope of 22.0 mV/decade of Zn(2+) concentration. The response time of the sensor is <10 s, and the membrane can be used for more than 3 months without any observed divergence in potentials. The proposed sensor exhibits very good selectivity for Zn(2+) over other cations and can be used in a wide pH range (2.8-7.0). It has also been possible to use this assembly as an indicator electrode in potentiometric titrations involving zinc ions. 相似文献
63.
Antibody microarrays are gaining popularity as a high-throughput technology to investigate the proteome. However, protein extracts from most body fluid or biopsy samples are available in very small volumes and are often unsuitable for large-scale antibody microarray studies. To demonstrate the potential for protein analysis with as little as a few nanoliters of sample, we have developed a new technology called NanoProbeArrays based on piezoelectric liquid dispensing for non-contact printing and probing of antibody arrays. Instead of flooding the protein sample on the antibody microarray surface, as in conventional microarray screening, a piezoelectric inkjet printer is used to dispense nanoliters of fluorescently labeled proteins over the antibody spots on the array. The ability of NanoProbeArrays to precisely identify and reliably distinguish between test proteins from different sources, without any loss of sensitivity and specificity as compared with conventional antibody microarrays, is illustrated here. The utility of NanoProbeArrays for biomarker identification in a complex biological sample was tested by detecting the cytokine interleukin-4 in serum. The significant reduction in volume of sample during NanoProbeArray analysis, as compared with conventional antibody microarrays, offers new opportunities for basic and applied proteomic research. 相似文献
64.
Jain A 《Multibody System Dynamics》2011,26(3):335-365
This second part of a two part paper uses concepts from graph theory to obtain a deeper understanding of the mathematical
foundations of multibody dynamics. The first part (Jain in Graph theoretic foundations of multibody dynamics. Part I. Structural
properties, 2010) established the block-weighted adjacency (BWA) matrix structure of spatial operators associated with serial- and tree-topology multibody system dynamics, and introduced
the notions of spatial kernel operators (SKO) and spatial propagation operators (SPO). This paper builds upon these connections to show that key analytical results and computational algorithms are a direct
consequence of these structural properties and require minimal assumptions about the specific nature of the underlying multibody
system. We formalize this notion by introducing the notion of SKO models for general tree-topology multibody systems. We show that key analytical results, including mass-matrix factorization, inversion,
and decomposition hold for all SKO models. It is also shown that key low-order scatter/gather recursive computational algorithms
follow directly from these abstract-level analytical results. Application examples to illustrate the concrete application
of these general results are provided. The paper also describes a general recipe for developing SKO models. The abstract nature
of SKO models allows for the application of these techniques to a very broad class of multibody systems. 相似文献
65.
66.
This article addresses the issue of visual landmark recognition in autonomous robot navigation along known routes, by intuitively
exploiting the functions of the human visual system and its navigational ability. A feedforward–feedbackward architecture
has been developed for recognising visual landmarks in real time. It integrates the theoretical concepts from the pre-attentive
and attentive stages in the human visual system, the selective attention adaptive resonance theory neural network and its
derivatives, and computational approaches towards object recognition in computer vision. The architecture mimics the pre-attentive
and attentive stages in the context of object recognition, embedding neural network processing paradigm into a computational
template-matching approach in computer vision. The real-time landmark recognition capability is achieved by mimicking the
pre-attentive stage, where it models a selective attention mechanism for optimal computational resource allocation, focusing
only on the regions of interest to address the computational restrictive nature of current computer processing power. Similarly,
the recognition of visual landmarks in both clean and cluttered backgrounds is implemented in the attentive stage by developing
a memory feedback modulation (MFM) mechanism that enables knowledge from the memory to interact and enhance the efficiency
of earlier stages in the architecture. Furthermore, it also incorporates both top-down and bottom-up facilitatory and inhibition
pathways between the memory and the earlier stages to enable the architecture to recognise a 2D landmark, which is partially
occluded by adjacent features in the surroundings. The results show that the architecture is able to recognise objects in
cluttered backgrounds using real-images in both indoor and outdoor scenes. Furthermore, the architecture application in autonomous
robot navigation has been demonstrated through a number of real-time trials in both indoor and outdoor environments. 相似文献
67.
Clubfoot is a challenging structural foot abnormality in babies and generally occurs at birth or during childhood. Due to this the abnormal posturing of the foot causes the babies to turn the ankle inward and walk along the outside edges of the foot. In medical science it is known as “congenital talipes equino varus” (CTEV). Computer modeling of prosthesis and orthosis is a perspective method for optimal design and gait is a terminology related to walking patterns of human subject. 相似文献
68.
69.
We introduce the concert (or cafeteria) queueing problem: A finite but large number of customers arrive into a queueing system
that starts service at a specified opening time. Each customer is free to choose her arrival time (before or after opening
time), and is interested in early service completion with minimal wait. These goals are captured by a cost function which
is additive and linear in the waiting time and service completion time, with coefficients that may be class dependent. We
consider a fluid model of this system, which is motivated as the fluid-scale limit of the stochastic system. In the fluid
setting, we explicitly identify the unique Nash-equilibrium arrival profile for each class of customers. Our structural results
imply that, in equilibrium, the arrival rate is increasing up until the closing time where all customers are served. Furthermore,
the waiting queue is maximal at the opening time, and monotonically decreases thereafter. In the simple single class setting,
we show that the price of anarchy (PoA, the efficiency loss relative to the socially optimal solution) is exactly two, while
in the multi-class setting we develop tight upper and lower bounds on the PoA. In addition, we consider several mechanisms
that may be used to reduce the PoA. The proposed model may explain queueing phenomena in diverse settings that involve a pre-assigned
opening time. 相似文献
70.
Multimedia Tools and Applications - In this paper, a blind image watermarking scheme based on discrete wavelet transform (DWT) and singular value decomposition (SVD) is proposed. In this scheme,... 相似文献