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901.
A method is proposed for the numerical analysis of the thermoelastoplastic stress-strain state of laminated shells of revolution, made of isotropic and orthotropic materials, under axisymmetric loading. The method is based on the Kirchhoff-Love hypotheses for a layer stack, the theory of deformation along paths of small curvature for isotropic materials, and Hills theory of flow with isotropic hardening for orthotropic materials. The problem is solved by the method of successive approximations. A numerical example is given.__________Translated from Prikladnaya Mekhanika, Vol. 40, No. 12, pp. 84–91, December 2004. 相似文献
902.
1 TheFlowModelofPower_LawFluidinRadicalFractalReservoirThetransientflowofpower_lawfluidinradicalfractalreservoirisstudiedinRef.[1 ] ,andanalyticalsolutionofLaplacespaceisderived .InRef.[2 ] ,thetransientellipticalflowisresearchedonmodelofexpandingrectangle .T… 相似文献
903.
This experimental investigation deals with transition phenomena of a separated boundary layer under unsteady inlet flow conditions.
The main purpose of this investigation is to understand the influence of the rotor-stator interaction in turbomachinery on
the subsequent, highly loaded boundary layer. The research project is divided into two phases. In the first phase, which has
been completed recently, only the variation of mean velocity caused by upstream blades was simulated in the experiments while
the free-stream turbulence intensity was retained at a constant low level. The experiments are carried out in an Eifel-type
wind tunnel to investigate the laminar separated boundary layer of a flat plate under oscillating inlet conditions. The adverse
pressure gradient, similar to that of turbomachines, is generated by the contoured upper wall. The unsteadiness is produced
by a rotating flap located downstream of the test section. The reduced frequency, the amplitude and the mean Reynolds number
are varied to simulate the conditions prevailing in turbomachines. In addition to the Kelvin–Helmholtz instability of the
separated shear layer, a lower frequency instability was observed. This is frequently referred to as `free shear layer flapping'
and results in two distinctly different ways of re-attachment, depending primarily on the Reynolds number. For low momentum
thickness Reynolds numbers at the separation point, large-scale vortices locked to the frequency of the unsteady main flow
are identified. They originate nearly at the top of the separation bubble and are ejected downstream. A fully turbulent boundary
layer develops after these vortices mix out. For higher Reynolds numbers, transition is completed within a short length of
the free shear layer and there-attachment region. The characteristic momentum thickness Reynolds number separating these two
regimes in unsteady flow is about 125. The Strouhal number (reduced frequency) does not appear to have any significant effect.
Based on the experimental results, this behaviour is discussed in some detail.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
904.
Evgeny Yu. Taran Yury V. Pridatchenko Vera A. Gryaznova 《Comptes Rendus Mecanique》2004,332(4):279-284
The problem of rotary motion of rigid axially symmetric elongated particles in the Couette flow of dilute suspension with anisotropic carrier fluid is solved. It is shown that the stable stationary solutions of the dynamical set of ordinary differential equations describing the particles rotary motion are possible in the case of forming the stationary anisotropy in the carrier fluid of the suspension. It allows us to detect the stationary orientation of suspended particles and formation of stable anisotropic liquid-crystalline structures in the considered suspension under the action of hydrodynamic forces. The study of rheological properties of such a structured suspension shows that it behaves as a viscoelastic quasi-Newtonian anisotropic liquid medium. To cite this article: E.Yu. Taran et al., C. R. Mecanique 332 (2004). 相似文献
905.
906.
W.N. Dawes 《International Journal of Heat and Fluid Flow》1983,4(1):17-26
A fully implicit algorithm has been developed to time integrate the equations of 2-D compressible viscous flow. The algorithm was constructed so as to optimize computational efficiency. The time-consuming block matrix inversions usually associated with implicit algorithms have been reduced to the trivial non-iterative inversion of four sets of scalar bidiagonal matrices. Thus, the algorithm requires virtually no more computer storage than an explicit algorithm. The efficient structure of the implicit algorithm is reflected in comparative timings which slow that it requires only a factor of two more computer time per point per time step than a typical explicit algorithm. Therefore, the algorithm allows more economical solution of given flows than existing explicit methods and also allows more difficult problems to be attempted using available computer resources. Application of the algorithm to the problem of shock-boundary layer interaction produces results consistent with both experimental measurements and other calculations. 相似文献
907.
Temporal sequences of planar laser-induced fluorescence (PLIF) images of several high-speed, transient flowfields created in a reflection-type shock tunnel facility were acquired. In each case, the test gas contained either nitric oxide or the hydroxyl radical, the fluorescent species. The processes of shock reflection from an endwall with a converging nozzle and of underexpanded free jet formation were examined. A comparison was also made between PLIF imaging and shadow photography. The investigation demonstrated some of the capabilities of PLIF imaging diagnostics in complex, transient, hypersonic flowfields, including those with combustion.Nomenclature
A
spontaneous emission rate
-
A
las
cross sectional area of laser sheet
-
B
laser absorption rate
-
C
opt
constant dependent on optical arrangement, collection efficiency, etc.
-
D
nozzle throat diameter
-
E
p
laser pulse energy
-
f
J
Boltzmann fraction of absorbing state
-
g
spectral convolution of laser and absorption lineshapes
-
k
Boltzmann constant
-
M
s
incident shock Mach number
-
N
noise, root-mean-square signal fluctuation
-
P
static pressure
-
P
1
initial pressure of test gas in shock tube
-
P
a
free jet ambient pressure
-
P
s
stagnation pressure
-
Q
electronic quenching rate of excited state
-
S
PLIF signal
-
t
time between shock reflection and image acquisition
-
T
static temperature
-
T
s
stagnation temperature
-
a
mole fraction of absorbing species 相似文献
908.
本文应用激光多普勒测速仪对二种转盘萃取塔模型进行切向速度、轴向速度和湍流度测量。实验结果表明,在RDC是切向速度比较大,因而有较大的搅拌效果,它的内部流场比较均匀稳定,有利于传质,所以RDC是广泛应用于化学工业中的一种液-液萃取设备。 相似文献
909.
910.
本文以量级分析为基础,建立了一般曲线坐标系上的三维旋转边界层方程。对旋转在边界层中的影响进行分析之后,提出了一个能够处理壁面法向压力梯度不为零问题的压力梯度迭代方法。在传统的Box法的基础上发展了一套完整的求解三维旋转边界层的方法和程序,并对螺旋面、压气机转子叶面以及圆柱面上的旋转边界层进行了计算,与他人的计算和实验的对比分析表明,该方法和程序是正确的,可用于求解任意几何物面上的三维旋转边界层。 相似文献