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51.
T.J. Woods 《Physics letters. [Part B]》1974,50(3):302-304
It is proposed that T< states which strongly mix with analog states to give states of mixed isospin results in the enhancement of the probability of proton decay from highly excited nuclear states. Such considerations are shown to explain the anomalies observed in the () reactions. 相似文献
52.
The 68Zn(, α)66Cu reaction populating low-lying states in 66Cu has been studied at θlab = 4° using deuteron beams in the energy range 9.0 to 10.5 MeV. Tensor analyzing powers were calculated and natural- or unnatural-parity assignments were made for thirteen states in 66Cu. By combining these results with existing limits unambiguous Jπ assignments of 2+, 2+, 2+ and 1+ have been made for the levels at 186, 465, 822 and 1344 keV respectively. The previous tentative assignments to seven other levels have been confirmed while that for the 1247 keV level has been shown to be incorrect. The identification of the quartet of levels based on the configuration has been confirmed. 相似文献
53.
Studies of the structural, physical, and chemical properties of the lanthanide(III) complexes of DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) and related ligands are often complicated by the presence of two coordination isomers in solution. Since these coordination isomers are in exchange and cannot be separated, many techniques offer information only on the weighted average of the two isomers. Lanthanide ion complexes formed with the ligands S(RRRR)NO2BnDOTMA and S(SSSS)NO2BnDOTMA preferentially adopt only one of the two common coordination isomers in solution, so the ytterbium complexes of these ligands offer a unique opportunity to study the near-infrared circular dichroism (NIR-CD) characteristics of each coordination geometry in isolation. The spectra acquired support many of the conclusions and assumptions of previous studies and demonstrate that this spectroscopy is particularly sensitive to the distortion of the coordination polyhedron. This will have particularly relevant consequences when studying achiral YbDOTA-like systems forming labile adducts with (chiral) hosts and receptors. 相似文献
54.
The electrical resistivity of four lithium-magnesium alloys with magnesium concentrations of 1.0, 5.0, 10 and 20 atomic percent has been measured as the specimens were slowly cooled from 300 K to ~3 K and warmed again to 300 K. From a hysteresis in the resistivity in the region of the martensitic transformation the Ms temperatures were found. Ms increases ~5 K per atomic percent of added magnesium and, while in agreement with Dugdale and Gugan the martensite in the dilute alloy is less resistive than the high temperature (bcc) phase, it has a larger resistivity in three less dilute alloys. 相似文献
55.
B.R. Marx K.P. Birch R.C. Felton B.W. Jolliffe W.R.C. Rowley P.T. Woods 《Optics Communications》1980,33(3):287-291
The SO2 molecule is of considerable interest in the context of atmospheric pollution, and in many laser monitoring techniques the ultraviolet absorption band at 300 nm is used to determine SO2 concentrations in the atmosphere. Recent laboratory experiments with a resolution of 2 × 10-3 nm showed that variations could occur in absorption cross-section measurements made with different laser bandwidths due to unresolved fine structure. We have investigated absorption spectra with a line width of 3 × 10-6 nm, using a frequency-doubled continuous-wave dye laser, and have confirmed the existence of fine structure in the absorption even when collisionally broadened with an atmosphere of nitrogen. These measurements provide a data base from which valid absorption cross sections may be calculated for all monitoring laser bandwidths. We estimate the pressure broadening coefficient for nitrogen in this wavelength region as 83 ± 38 kHz Pa-1 (11 ± 5 MHz torr-1). The temperature dependence of the absorption cross-section was also investigated. 相似文献
56.
Data for the 58,60Ni(6Li, d) 62,64Zn reactions, together with an analysis in terms of a simple multipole pairing model, indic that two-phonon states are extremely weakly excited. This result arises from the dominance of monopole pairing correlations in four-particle transfer reactions and explains the observed correspondence between two- and four-particle transfer reactions populating the same final nucleus. 相似文献
57.
Neutron inelastic scattering from 4He at T = 2.3 K shows that for Q ? 2 nm?1 “sound-wave” excitations propagate with the characteristics of ordinary or first sound while for Q ? 3 nm?1 they propagate with the characteristics of zero sound. 相似文献
58.
Blocking is often used to reduce known variability in designed experiments by collecting together homogeneous experimental units. A common modeling assumption for such experiments is that responses from units within a block are dependent. Accounting for such dependencies in both the design of the experiment and the modeling of the resulting data when the response is not normally distributed can be challenging, particularly in terms of the computation required to find an optimal design. The application of copulas and marginal modeling provides a computationally efficient approach for estimating population‐average treatment effects. Motivated by an experiment from materials testing, we develop and demonstrate designs with blocks of size two using copula models. Such designs are also important in applications ranging from microarray experiments to experiments on human eyes or limbs with naturally occurring blocks of size two. We present a methodology for design selection, make comparisons to existing approaches in the literature, and assess the robustness of the designs to modeling assumptions. 相似文献
59.
Abstract Embedded cluster calculations performed on both ground (4A2g) and excited (4T2g) states of substitutional Cr3+ in halide elpasolites account successfully for the pressure dependence of photoluminescence spectra. 相似文献
60.
Wu Y Zhou Y Ouari O Woods M Zhao P Soesbe TC Kiefer GE Sherry AD 《Journal of the American Chemical Society》2008,130(42):13854-13855
Linear polymers of PARACEST agents were prepared by using classical free radical chain polymerization conditions. The Eu3+-polymers exhibited similar intermediate-to-slow water exchange and CEST characteristics as the Eu3+-monomers. This provided an avenue to lower the detection limit of these imaging agents substantially and makes them potentially useful as MRI sensors for molecular imaging. 相似文献