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81.
By optimizing pump power ratio between 1st order backward pump and 2nd order forward pump on discrete Raman amplifier, we demonstrated over 2dB noise figure improvement without excessive non-linearity degradation.  相似文献   
82.
The boundary of a fractal object, represented in a two-dimensional space, is theoretically a line with an infinitely small width. In digital images this boundary or contour is limited to the pixel resolution of the image and the width of the line commonly depends on the edge detection algorithm used. The Minkowski dimension was evaluated by using three different edge detection algorithms (Sobel, Roberts, and Laplace operator). These three operators were investigated because they are very widely used and because their edge detection result is very distinct concerning the line width. Very common fractals (Sierpinski carpet and Koch islands) were investigated as well as the binary images from a cancer invasion assay taken with a confocal laser scanning microscope. The fractal dimension is directly proportional to the width of the contour line and the fact, that in practice very often the investigated objects are fractals only within a limited resolution range is considered too.  相似文献   
83.
Frank E. Harris 《Pramana》2003,61(4):C779-C780
Guseinov, Mamedov, Kara and Orbay (Pramana - J. Phys. 56, 691 (2001)) propose methods for evaluating the molecular auxiliary functionsA n(p) andB n(pt) for the range 17 ≤n ≤ 60 and 25 ≤pt ≤ 60. However, their procedure forA n(p) is not new, and that forB n(pt) is less efficient for their target range than another well-known method. Their approach does have merit for smaller non-zero values ofpt. Two minor errors in table 1 of their paper are also identified.  相似文献   
84.
The resolvent method approach is proposed for analytically solving the time domain Volterra integral equation (TDVIE) which describes the electromagnetic fields in 2-D cylindrical structures with time changes in the permittivity. It is shown that the approach allows investigation of the electromagnetic field transformation due to an abrupt time change in dielectric permittivity inside a circular cylinder as well as the construction of the Green’s function for an initial-boundary value problem. Key mechanisms of electromagnetic field transformation are investigated and a qualitative distinction of the processes is shown that depends on an initial field configuration.  相似文献   
85.
Research into microdisk lasers demonstrates new achievements both in the technology and in the associated physical effects and applications. Melting and rounding of the disk edge boosts the Q-factors due to improved surface smoothness. In-plane cavity shape is widely used as a design instrument. Optimal shaping of pumped area lowers the threshold power. Photonic molecules made of several microdisks as “photonic atoms” show lasing at several closely spaced frequencies. A microdisk with a single quantum dot as an active region is considered as the most promising system for realisation of a single photon emitter necessary for quantum computing. These new effects and devices can be simulated with accurate numerical techniques, developed recently for “warm-cavity” linear modelling, that are able to bring a new vision of the physics of lasing.  相似文献   
86.
A microwave-assisted method is described for monoacylating 7-amino-5-aryl-6-cyanopyrido[2,3-d]pyrimidines using excess acid chlorides in pyridine. A diacylated intermediate is effectively deacylated to the product amide by a macroporous-Tris resin. A small library of 17 amides was prepared to validate the method. The integration of commercial microwave technology into the ArQule chemistry platform is also discussed.  相似文献   
87.
The preparation of hard material samples with the necessary size and shape is critical to successful material analysis. X‐ray nanotomography requires that samples are sufficiently thin for X‐rays to pass through the sample during rotation for tomography. One method for producing samples that fit the criteria for X‐ray nanotomography is focused ion beam/scanning electron microscopy (FIB/SEM) which uses a focused beam of ions to selectively mill around a region of interest and then utilizes a micromanipulator to remove the milled‐out sample from the bulk material and mount it on a sample holder. In this article the process for preparing X‐ray nanotomography samples in multiple shapes and sizes is discussed. Additionally, solid‐oxide fuel cell anode samples prepared through the FIB/SEM technique underwent volume‐independence studies for multiple properties such as volume fraction, average particle size, tortuosity and contiguity to observe the characteristics of FIB/SEM samples in X‐ray nanotomography.  相似文献   
88.
Bai JZ  Ban Y  Bian JG  Chen AD  Chen HF  Chen HS  Chen JC  Chen XD  Chen YB  Cheng BS  Chi SP  Chu YP  Choi JB  Cui XZ  Dai YS  Dong LY  Du ZZ  Dunwoodie W  Fu HY  Fu LP  Gao CS  Gu SD  Guo YN  Guo ZJ  Han SW  Han Y  Harris FA  He J  He JT  He KL  He M  He X  Hong T  Heng YK  Hu GY  Hu HM  Hu QH  Hu T  Huang GS  Huang XP  Huang YZ  Izen JM  Ji XB  Jiang CH  Jin Y  Jones BD  Kang JS  Ke ZJ  Kim HJ  Kim SK  Kim TY  Kong D  Lai YF  Li D  Li HB  Li HH  Li J  Li JC  Li PQ  Li QJ  Li RY  Li W  Li WG  Li XN  Li XQ  Liu B  Liu F  Liu F  Liu HM  Liu J  Liu JP  Liu TR 《Physical review letters》2002,88(10):101802
We report values of R = sigma(e(+)e(-)-->hadrons)/sigma(e(+)e(-)-->mu(+)mu(-)) for 85 center-of-mass energies between 2 and 5 GeV measured with the upgraded Beijing Spectrometer at the Beijing Electron-Positron Collider.  相似文献   
89.
A multiferroic heterostructure, consisting of a 25 μm thick Metglas® ribbon affixed to a lead magnesium niobate–lead titanate (PMN-PT) crystal, was systemically studied to investigate the time response of converse magnetoelectric coupling under the application of electric fields at low frequencies (0.05<f<10 Hz). This multiferroic heterostructure exhibits a considerably strong converse magnetoelectric effect, CME=?80%, where CME=[M(E)?M(0)]/M(0), and a converse ME coupling constant, A=22.5 Oe-cm/kV, at frequencies below 1 Hz and near saturation electric polarization. A switching time (t s), representing the response time of the CME coupling, is measured to be 0.6 seconds for this heterostructure under the application of instantaneous electric fields. The switching time results in significant influences on the magnetoelectric effect especially at frequencies higher than 2 Hz. The dynamic response of CME coupling is predominantly determined by ferroelectric relaxation within the PMN-PT crystal, as opposed to the magnetic relaxation of the Metglas® ribbon. A model was used to describe the dynamic behavior of CME coupling in disordered systems such as PMN-PT.  相似文献   
90.
Lines in the ν3 (“antisymmetric” stretch) fundamental of the NCO radical in the X?2Π state were studied by CO laser magnetic resonance. The observations were assigned to P and R lines in the vibration-rotation band and lead to a precise determination of the vibrational interval and the anharmonic correction to the rotational constant: ν3 = 1920.60645(19) cm?1, α3 = 0.003338(21) cm?1. A single transition in the hot band (011)-(010), 2Δ52-2Δ52 was detected. This observation is used to determine the origin of the hot band as 1907.11892(20) cm?1, i.e., the anharmonicity parameter x23 = ?13.48753(28) cm?1.  相似文献   
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