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81.
Distinctions are drawn between three mean strain rates in extrusion: those averaged over the accumulated strain, the distance
travelled through the die, and the elapsed time. It is shown that when the strain rate varies, the mean strain rate based
on strain is always the greatest, and the mean strain rate based on time the smallest. Three further mean strain rates are
introduced, which are root mean power (RMP) values of the above strain rates. Conventional estimates of the extrusion pressure
for frictionless, homogeneous flow are based on rate insensitive analyses and lead to pressures proportional to the mean strain
rate based on time. When the rate sensitivity during flow is taken into account, the calculated pressure is shown to be a
function of the RMP strain rate based on accumulated strain, which is considerably greater than the mean strain rate based
on time. Experiments are described in which ice was extruded by the indirect process, leading to nearly frictionless, homogeneous
flow. Extrusion ratios of 4, 9, 25, 81, and 144 were used. In the first series of experiments, the ram velocity was adjusted
to give the samerate insensitive (i.e. time-based) mean strain rate for all the dies. In the second series of experiments, the ram velocity was adjusted to give
the samerate sensitive (i.e. RMP) mean strain rate for all the dies. In all cases the extrusion pressure was proportional to the RMP strain rate and not
to the time-based strain rate. The rate sensitivity correction factor is also described. 相似文献
82.
Electrically quantitated and controlled detrusor contraction can produce either minimal or excessive rise in intravesical pressure depending upon openness or occlusion of the bladder outlet. Higher rise in intravesical pressure thus does not imply stronger detrusor contraction but should be viewed as a reflection of the outflow resistance mechanism. Possible damaging hydrodynamic effect of sudden partial or complete functional occlusion of the bladder outlet by intermittent or sustained voluntary sphincter activity is illustrated. 相似文献
83.
We have developed a novel strategy to identify enzyme inhibitors that interact directly with their enzyme targets. In the approach, an enzyme is immobilized on a sensor chip, and it is determined whether the immobilized enzyme is still active by incubation with model substrates and mass spectrometric analysis of the products. Putative inhibitors or mixtures containing putative inhibitors are then injected over the sensor chip for binding analysis with surface plasmon resonance. It is then tested whether the bound compounds inhibit the enzymatic activity by subsequent incubation with the model substrate and mass spectrometric analysis. If the bound compound inhibits the enzyme, the inhibitor is eluted from the enzyme and characterized by mass spectrometry. To test the strategy, it has been applied to the well-characterized interaction between trypsin and pure bovine pancreas trypsin inhibitor. Furthermore, fractions of plant extracts were screened for binding to and inhibition of carboxypeptidase B. 相似文献
84.
Nonpolar lipids and sound velocity at different distances from the skin surface within a sample of pilot whale melon were
studied. Thin layer chromatography, sensitive radioisotopic methods, and an ultrasonic echo scanner were used. Wax esters
had a maximum concentration at 11–12 cm from the skin surface. Non- and monoisovalero triglycerides both exhibited a minimum
at 8–10 cm, whereas the diisovalero species increased steadily from the skin surface towards the center of the pilot whale
head. A minimum of sound velocity, ca. 1340 m/s, was found at 9–11 cm, thus coinciding with a region rich in isovaleric acid
esterified in wax and diisovalero triglycerides. These findings are compatible with predictions based on the known correlations
between lipid structure and sound velocity. Consequently, additional evidence for refraction of sound in pilot whale melon
is presented. This is important in understanding the system of echolocation of toothed whales. 相似文献
85.
We study the potential of delayed feedback stimulation administered via multiple sites to control the synchronization and
the spatio-temporal activity pattern within a network of oscillators. Two models with different levels of complexity are investigated:
an ensemble of phase oscillators is used to study and analyze the effects of the stimulation in detail and a microscopic model
is presented to exemplify the effectiveness of the method in terms of a stable desynchronization continuously maintained under
realistic conditions. The investigation shows that depending on the spatial stimulation profile a multi-cluster state or a
fully desynchronized state results. Both states are characterized by a strong suppression of the first order parameter indicating
a strong desynchronization. Multisite delayed feedback stimulation realizes a demand-controlled stimulation which stabilizes
the desired desynchronized state while the used stimulation current is minimized. We propose the method to be tested as a
therapy of diseases characterized by pathological synchronization and for the therapy of defective neuronal pattern generators. 相似文献
86.
Anselmo Antunes Montenegro Luiz Velho Paulo C. P. Carvalho Jonas Sossai Jr. 《Journal of Mathematical Imaging and Vision》2007,29(2-3):119-130
In this work we propose a method for computing mesh representations of 3D objects reconstructed from a set of silhouette images.
Our method is based on the polygonization of volumetric reconstructions by using a modified version of the dual contouring method. In order to apply dual contouring on volumetric reconstruction from silhouettes we devised a method that is able
to determine the discrete topology of the surface in relation to the octree cells. We also developed a new scheme for computing
hermitian data representing the intersections of conic volumes with the octree cells and their corresponding normals with
subpixel accuracy. Due to the discrete and extremely noisy nature of the data used in the reconstruction we had to devise
a different criterion for mesh simplification that applies topological consistency tests only when the geometric error measure
is beyond a given tolerance. We present results of the application of the proposed method in the extraction of a mesh corresponding
to the surface of objects of a real scene. 相似文献
87.
Two-tier streaming settings are a typical dynamic environment where continuous skylines represent an important semantic indicator for multiple attributes. To monitor skylines over the dynamic data in such settings, one needs to continuously update the skyline query results in order to reflect the new data values. This paper tackles the problem of continuous skyline monitoring on a central query server over dynamic data from multiple data sites. Simply sending the updates of tuple values to the server is cost-prohibitive. Therefore, we propose an approach that allows the central server to collaborate with the data sites to monitor the possible skyline changes. By doing so, the processing load is distributed over all the data sites instead of only on the central server. Furthermore, this collaborative approach minimizes the bandwidth consumption between the server and the data sites, which is often critical in a widely distributed environment such as a wide-area sensor network. We give theoretical upper bounds for the computation costs and communication costs of the proposed collaborative approach. We also conduct extensive experiments on both synthetic and real data sets. The experimental results demonstrate that our collaborative approach is efficient, scalable and well-balanced in terms of communication costs and computation costs. 相似文献
88.
This study develops a model for inventory management consisting of a two-echelon supply chain (SC) with profit sharing and deteriorating items. The retailer and the supplier act as the leader and follower, in which the supplier faces a huge setup cost and economic order quantity ordering strategy. The market demand is affected by the sale price of the product, and the inventory has a deterioration rate following a Weibull distribution. The retailer executes three profit-sharing mechanisms to motivate the supplier to participate in SC optimisation and to extend the life cycle of the product. A search algorithm is developed to determine the solutions as using the profit-sharing mechanisms. The outcomes from numerical experiments demonstrate the profitability of the proposed model. 相似文献
89.
Examination of the Transferability of Technological key Features of Paperboard Deep Drawing Towards the Application in Fast‐Running Packaging Machines 下载免费PDF全文
Marek Hauptmann Thomas Kustermann Manfred Schmalholz Hans Haug Jens‐Peter Majschak 《Packaging Technology and Science》2017,30(1-2):21-31
The deep‐drawing process of paperboard has experienced essential improvement in the recent past; however, the technological advancements have not been transferred to packaging machines yet. Two of the most important issues with regard to the reliable production of high quality 3D shapes are the use of elevated moisture and defined blank holder force profiles. This paper examines a roll preparation method for applying additional water to the paperboard and analyses a spring‐loaded blank holder solution with regard to its achieved accuracy and reliability of the force characteristics. A two‐sided roll application of water on the paperboard using a sponge rubber cover on one of the rolls produces a water intake of up to 12%. The effect of moisture applied by roll preparation is higher compared to conditioning under controlled climate conditions, and the preparation time is reduced to a few seconds. The spring‐loaded blank holder introduced in the paper completely works in position control and avoids the switch over to force control as well as the problem of small position steps, which were necessary during force control. A harmonic oscillation of the blank holder while the material is drawn out of it could not be observed up to an output of 150 cycles per minute. An application of a roll‐based moisturization unit and a spring‐loaded blank holder force in modern packaging machines appears feasible and favourable according to the results of this paper and maintains the capabilities of this 3D forming technology to a large part. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
90.
For this study, 194 respondents completed a biographical data sheet, the Templer (1970) Death Anxiety Scale and the Constantinople (1973) Inventory of Psychosocial Development to help assess the relationship among death anxiety, age, and psychosocial maturity. Findings showed that psychosocial maturity was a better predictor of death anxiety than age was. However, both variables were significantly negatively correlated with death anxiety, revealing that as psychosocial maturity and age increase, death anxiety decreases. 相似文献