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191.
Quan Xu Fan Fan Zhaohui Lu Mao Sheng Shouceng Tian Ye Zhang Linhua Pan Yang Zhou 《中国化学快报》2021,32(1):553-556
Proppant is a key material in the hydraulic fracturing process,which has been widely used in unconventional oil exploitation.Normal proppants are easy to sedimentate and accumulate at the entrance of shale fracture,which will block the diversion of water,oil and gas.Coated proppants(CPs) are fabricated by coating resin on normal ceramic proppants through a simple method,which is dramatically enhanced the supporting properties in shale fracture and easy to scale up.Compared with uncoated ceramic proppants,the self-suspension ability of CPs is ~11 times higher,which are able to migrate and distribute farther and deeper inside the fracture.At the same time,Coating enhanced the 23.7% of adhesive force in maximum,which makes the CPs easier to adhere on the fracture surface to supportthe shale fracture.Besides,the liquid conductivity of CPs is 60% higher than uncoated ceramic proppants at13.6 MPa pressure.This method is expected to fabricated varieties of proppantsfor shale fracture supporting to improve the exploration of unconventional oil and gas resources. 相似文献
192.
193.
194.
M. A. Elganainy 《Applied Mathematical Modelling》1986,10(6):394-400
This paper presents a solution, using a conformal mapping technique, for the problem of seepage beneath two structures with intermediate filter built on two pervious strata. The lower stratum has a higher permeability than the upper one. Formulae are derived for calculating the dimensionless heads acting on both the upstream and downstream structures. Also, equations are derived for determining the values of the exit gradients along both the intermediate filter and the downstream bed, and the seepage discharges. For given boundary conditions, the seepage characteristics are calculated using the derived formulae; a sample from the results of such calculations is presented. 相似文献
195.
The problem of gas fracture formation in a porous medium is investigated. An inertialess viscous polytropic gas flow along the fracture is considered. The assumption of small fracture width with respect to the height and length makes it possible to adopt the vertical plane cross-section hypothesis on the basis of which the dependence of the gas pressure inside the fracture on its width can be reduced to a linear law. Initially, the soil surrounding the fracture is soaked with oil-bearing fluid. During fracturing the reservoir gas penetrates into the soil mass and displaces the fluid. A closed system of equations, which describes the evolution of the fracture opening, the depth of gas penetration into the reservoir, and the gas velocities inside the fracture, is constructed. The limiting regimes of gas seepage into the surrounding reservoir are considered and a one-parameter family of self-similar solutions of the system is given for each. The asymptotics of the solution in the neighborhood of the fracture nose is investigated and analytic expressions for the fracture length are obtained. The solution of the problem of gas fracture is compared with the hydraulic fracturing problem in an analogous formulation within the framework of the plane cross-section hypothesis. 相似文献
196.
Connectivity and Effective Hydraulic Conductivity 总被引:1,自引:0,他引:1
Donald A. Nield 《Transport in Porous Media》2008,74(2):129-132
The effect of the connectivity of high-conductivity elements on the value the effective hydraulic conductivity of a saturated
porous medium is investigated. The increase in effective conductivity due to the connectivity is estimated on the basis of
a simple combinatorial model. 相似文献
197.
Bernhard Manhartsgruber Gudrun Mikota Rudolf Scheidl 《Mathematical and Computer Modelling of Dynamical Systems: Methods, Tools and Applications in Engineering and Related Sciences》2013,19(3):329-344
Modelling of a hydraulic system featuring a specific type of switching control is presented. Despite conventional hydraulic drive technology where rather smooth changes of pressure and flow rate are intended and where oscillations constitute undesired phenomena, switching control provokes oscillations as an indispensable element to achieve high energetic efficiency with valve control. The system under study is one which comprises a novel switching valve, a long line with considerable wave propagation dynamics, a hydraulic cylinder, and the valve's dynamics. 相似文献
198.
Karim?Beddiar Teddy?Fen-ChongEmail author André?Dupas Yves?Berthaud Patrick?Dangla 《Transport in Porous Media》2005,61(1):93-107
Electro-osmosis experiments were conducted on rigid cylindrical samples containing 0.01 M NaCl–water saturated Speswhite kaolinite. It is experimentally found that the electro-osmotic permeability is pH-dependent. It is also experimentally found that time and spatial variations of the sample pH and of the pore water pressure correlate. This is qualitatively confirmed by a simple analysis that couples the electro-osmotic and hydraulic flows through the pH-dependent electro-osmotic permeability. However quantitative agreement between the experimental and numerical values of the pore water pressure is not obtained throughout the whole sample. This suggests that the hydraulic permeability may also depend on the pH. 相似文献
199.
Cluster statistics of percolation theory have been shown to generate expressions for the distribution of hydraulic conductivity values in accord with field studies. Percolation theory yields directly the smallest possible generalized resistance value, R
c, for which a continuous path through an infinite heterogeneous system can avoid all larger resistances. R
c, defines an infinite system hydraulic conductivity. Cluster statistics generate the number of clusters of resistors of a given size with a given R, for which a continuous path through the cluster can avoid resistances larger than R. The probability that a volume of size x
3 falls on a particular cluster gives the probability that volume has a characteristic resistance, R. Determining the semi-variogram of the hydraulic conductivity is now elementary; it is necessary only to determine whether translation h of the center of the volume x
3 removes it from the cluster in question. If the cluster is larger than (x+h)3, then, on the average, the same cluster resistance R will control K. Otherwise, the value of K at x+h will be uncorrelated with its value at x. The condition is then expressed as an integral related to the one, which gives the distribution of K. Then an integral over the derived distribution of K gives the variogram. Results obtained are that the variogram should be similar to either the exponential or Gaussian forms typically in use, if K is a power law function of random variables (as in Poiseuilles Law), or more closely related to the spherical approximation if K is an exponential function of random variables. 相似文献
200.
本文运用正交试验法对东方红 - 40拖拉机液压悬挂系统上拉杆受力因素进行方差分析 ,寻求合理的生产条件 相似文献