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91.
Ethylene (ethene, H2C=CH2) is a naturally occurring compound in ambient air that affects atmospheric chemistry and global climate. The C2H4 spectrum is available in databases only for the 1000 and 3000 cm−1 ranges.In this work, the ethylene absorption spectrum was measured in the 6030-6250 cm−1 range with the use of a high resolution Bruker IFS 125HR Fourier-spectrometer and a two-channel opto-acoustic spectrometer with a diode laser. As a secondary standard of wavelengths, the methane absorption spectrum was used in both cases.A preliminary analysis was realized thanks to the tensorial formalism developed by the Dijon group that is implemented in the XTDS software package [39]. We considered the two combination bands ν5+ν9 and ν5+ν11 as an interacting dyad. Parameters for the ν9/ν11 dyad were fitted simultaneously from a re-analysis of previously recorded supersonic expansion jet FTIR data, while parameters for the v5=1 Raman level were taken from literature. More than 600 lines could be assigned in the 6030-6250 cm−1 region (and also 682 in the 2950-3150 cm−1 region) and effective Hamiltonian parameters were fitted, including Coriolis interaction parameters. The dyad features are globally quite well reproduced, even if there are still problems at high J values.  相似文献   
92.
This paper develops a theory of harmonic analysis on spaces with tree metrics, extending previous work in this direction by Gavish, Nadler and Coifman (2010) [30] and Gavish and Coifman (2011, 2012) [28], [29]. We show how a natural system of martingales and martingale differences induced by a partition tree leads to simple and effective characterizations of the Lipschitz norm and its dual for functions on a single tree metric space. The restrictions we place on the tree metrics are far more general than those considered in previous work. As the dual norm is equal to the Earth Mover's Distance (EMD) between two probability distributions, we recover a simple formula for EMD with respect to tree distances presented by Charikar (2002) [36].We also consider the situation where an arbitrary metric is approximated by the average of a family of dominating tree metrics. We show that the Lipschitz norm and its dual for the tree metrics can be combined to yield an approximation to the corresponding norms for the underlying metric.The main contributions of this paper, however, are the generalizations of the aforementioned results to the setting of the product of two or more tree metric spaces. For functions on a product space, the notion of regularity we consider is not the Lipschitz condition, but rather the mixed Lipschitz condition that controls the size of a function's mixed difference quotient. This condition is extremely natural for datasets that can be described as a product of metric spaces, such as word-document databases. We develop effective formulas for norms equivalent to the mixed Lipschitz norm and its dual, and extend our results on combining pairs of trees.  相似文献   
93.
In this paper the multi-stage digit filter is used to analyse the data of Earth rotation represented by the length of day, ΔLOD. The results show that the interannual variations of Earth rotation, which are in the time scale of several years but not quasi-periodic terms, exist in the long periodic fluctuations. They induce the relative variation in the length of day of 0.3×10~(-8).Comparing the series of length of day with the data of temperature departure of the sea surface in the equatorial area of the eastern Pacific, we found that the deceleration and acceleration of the interannual rate of Earth rotation are consistent with the warming up and down of sea temperature in the equatorial area very well. This means that every El Nio event always occurs after the turning of acceleration of the interannual rate of Earth rotation to deceleration.According to the strong interannual variation in the length of day and strong warming of the sea surface temperature in the equatorial area between 1982 and 1983  相似文献   
94.
A kind of copolymer of acrylic acid and vinylpyridine was synthesized and the fluorescent properties of the complexes of the copolymer with Eu~(3+) or Tb~(3+) were studied. It was found that the fluorescence intensity of the complexes of the eopolymer with Eu~(3+) was 20 times as high as that of the complexes of polyaerylic acid with Eu~(3+) and twice as high as that of the complexes of polyvinylpyridine with Eu~(3+). The effects of the composition of the copolymer and the content of Eu~(3+) or Tb~(3+) in the complexes were studied. The fluorescence lifetime of the complexes was measured and it was found that two or more kinds of energy transfer mechanism existed.  相似文献   
95.
Crystal Structures of CaBe2Ge2 and CeMg2Si2 analogous Units: The Phosphides LnPt2P2?x (Ln: La, Sm) Single crystals of LaPt2P1.44 (a = 4.174(1), c = 19.212(5) Å) were grown by reaction of vaporous phosphorus with LaPt2 at 1050 °C during two weeks, whereas SmPt2P1.50 (a = 4.131(1), c = 19.086(4) Å) was synthesized by heating mixtures of the elements at 900 and 1100 °C (60 h) and annealing at 1050 °C (300 h). Both phosphides were investigated by single crystal X‐ray methods. Their crystal structures (I4/mmm; Z = 4) consist of CaBe2Ge2 and CeMg2Si2 analogous units alternating with each other along [001]. The positions of the P1 atoms are occupied incompletely causing the deviation to the 1:2:2 stoichiometry. Another compounds LnPt2P2?x were studied by X‐ray powder diffraction resulting in the following lattice constants: a = 4.150(1), c = 19.132(5) Å for CePt2P2–x, a = 4.137(1), c = 19.085(4) Å for PrPt2P2?x, and a = 4.127(1), c = 19.040(2) Å for NdPt2P2?x.  相似文献   
96.
Ternary Halides of the A3MX6 Type. VI. Ternary Chlorides of the Rare-Earth Elements with Lithium, Li3MCl6 (M ? Tb? Lu, Y, Sc): Synthesis, Crystal Structures, and Ionic Motion Single crystal X-ray studies on the ternary chlorides Li3ErCl6, Li3YbCl6 and Li3ScCl6 show that they crystallize in three different structure types. Li3ErCl6 (trigonal, P3 ml, Z = 3, a = 1117.7(2); c = 603.6(2) pm; the chlorides with M ? Tb? Tm, Y are isotypic) and Li3YbCl6 (orthorhombic, Pnma, Z = 4, a = 1286.6(1); b = 1113.2(1); c = 602.95(8) pm; Li3LuCl6 is isotypic) have very similar structures that may be derived from hexagonal closest packings of chloride ions with the cations occupying octahedral holes in part statistically. Li3ScCl6 (monoclinic, C2/m, Z = 2, a = 639.8(1); b = 1104.0(2); c = 639,1(1) pm; β = 109.89(1)°) crystallizes isotypic with Na3GdI6 and Li3ErBr6, structures that may be derived from a cubic closes packings of anions. The ionic movement in Li3YCl6 and Li3YbCl6 has been investigated by impedance and 7Li-NMR spectroscopy.  相似文献   
97.
Amido Metalates of Rare Earth Elements. Syntheses and Crystal Structures of [Na(12-crown-4)2][M{N(SiMe3)2}3(OSiMe3)] (M = Sm, Yb), [Na(THF)3Sm{N(SiMe3)2}3(C≡C–Ph)], [Na(THF)6][Lu2(μ-NH2)(μ-NSiMe3){N(SiMe3)2}4], and of [NaN(SiMe3)2(THF)]2. Applications of Rare Earth Metal Complexes as Polymerization Catalysts The amido silyloxy complexes [Na(12-crown-4)2][M{N(SiMe3)2}3(OSiMe3)] with M = Sm ( 1 a ), Eu ( 1 b ), Yb ( 1 c ), and Lu ( 1 d ) were obtained from the trisamides M[N(SiMe3)3]3 and NaOSiMe3 in n-hexane in the presence of 12-crown-4; they form yellow to orange-red crystals, of which 1 a and 1 c were characterized crystallographically. The complexes crystallize isotypically with one another in the monoclinic space group I2/a with eight formula units per unit cell. The metal atoms of the complex anions are tetrahedrally coordinated by the three nitrogen atoms of the N(SiMe3)2 ligands and by the oxygen atom of the OSiMe3 ligand. With 172.4° for 1 a and 179.3° for 1 c the bond angles M–O–Si are practically linear. With ethynylbenzene in the presence of NaN(SiMe3)2 in tetrahydrofuran the trisamides M[N(SiMe3)2]3 react under formation of the complexes [Na(THF)3M{N(SiMe3)2}3 · (C≡C–Ph)] with M = Ce ( 2 a ), Sm ( 2 b ), and Eu ( 2 c ), of which 2 b was characterized crystallographically (monoclinic, space group P21/n, Z = 4). 2 b forms an ion pair in which the terminal carbon atom of the C≡C–Ph ligand is connected with the samarium atom of the Sm[N(SiMe3)2]3 group and the sodium ion is side-on connected with the acetylido group. According to the crystal structure determination (space group P212121, Z = 4) [Na(THF)6][Lu2(μ-NH2)(μ-NSiMe3) · {N(SiMe3)2}4] ( 3 ), which is formed as a by-product, consists of [Na(THF)6]+ ions and dimeric anions, in which the lutetium atoms are connected to form a planar Lu2N2 four-membered ring via a μ-NH2 bridge with average Lu–N distances of 227.2 pm and via a μ-NSiMe3 bridge of average Lu–N distances of 218.5 pm. According to the crystal structure determination (space group P 1, Z = 1) [NaN(SiMe3)2(THF)]2 ( 4 ) forms centrosymmetric dimeric molecules with Na–N distances of the Na2N2 four-membered ring of 239.9 pm and distances Na–O of the terminally bonded THF molecules which are 226.7 pm. The vinylic polymerization of methylmethacrylate (MMA) catalyzed by 1 c resulted in high molecular weight polymethylmethacrylate (PMMA) with moderate yields. The reaction of 1 a or 2 b with MMA did not give PMMA. Insoluble polynorbornene was obtained in low yields by reaction of norbornene/methylaluminoxane (MAO) with 1 a , 1 c , or 2 b . The ring opening polymerization of ϵ-caprolacton or δ-valerolacton catalyzed by 2 b resulted in corresponding polylactones in quantitative yields.  相似文献   
98.
Summary The absolute spectra of atmospheric neutrinos in the vertical direction and at large zenith angle have been estimated directly from the primary cosmic-ray nucleon spectrum based on the latest JACEE, MSU, SOKOL and CRN data surveyed by Swordy. The Fermi National Accelerator Laboratory results for pp→K±X, pp→K±X and pp→pX inclusive reactions have been used for theZ-factor calculations for meson production and these were modified for p-air and A-A collisions. The derived muon and electron neutrino spectra at 0° and 89° from non-prompt meson decay are found comparable with the results of Volkova and Zatsepin, and Butkevichet al. An estimate of the prompt muon neutrino spectra at 0° and 89° fromtthe charmed-meson decay has been given along with the earlier results of different authors. The present result for muon neutrino spectra at zenith angles 0° and 89° is found in approximate agreement with the EAS-TOP results of the Gran Sasso group.  相似文献   
99.
In this paper, we discuss a possibility of studying properties of dark energy in long baseline neutrino oscillation experiments. We consider two types of models of neutrino dark energy. For one type of models the scalar field is taken to be quintessence-like and for the other phantom-like. In these models the scalar fields couple to the neutrinos to give rise to spatially varying neutrino masses. We will show that the two types of models predict different behaviors of the spatial variation of the neutrino masses inside the Earth and consequently result in different signals in long baseline neutrino oscillation experiments.  相似文献   
100.
植物性食品中稀土元素的ICP-MS测定   总被引:3,自引:0,他引:3  
刘江晖  周华 《光谱实验室》2003,20(4):554-557
本文研究了ICP-MS同时测定植物性食品中16种稀土元素(Sc、Y、La、Ce、Pr、Nd、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb和Lu)的方法。采用以In作内标的校正形式,用微波消解样品,对照分析了参考标准物质。对所测定元素,校准曲线的相关系数为0.9999,回收率范围为94%-106%,相对标准偏差优于3.2%(n=11),检出限低于2.2pg/g(Sc为95pg/g)。  相似文献   
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