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排序方式: 共有927条查询结果,搜索用时 15 毫秒
911.
Sven Otto Dr. Joe P. Harris Prof. Katja Heinze Prof. Christian Reber 《Angewandte Chemie (International ed. in English)》2018,57(34):11069-11073
The intensely luminescent chromium(III) complexes [Cr(ddpd)2]3+ and [Cr(H2tpda)2]3+ show surprising pressure‐induced red shifts of up to ?15 cm?1 kbar?1 for their sharp spin‐flip emission bands (ddpd=N,N′‐dimethyl‐N,N′‐dipyridine‐2‐yl‐pyridine‐2,6‐diamine; H2tpda=2,6‐bis(2‐pyridylamino)pyridine). These shifts surpass that of the established standard, ruby Al2O3:Cr3+, by a factor of 20. Beyond the common application in the crystalline state, the very high quantum yield of [Cr(ddpd)2]3+ enables optical pressure sensing in aqueous and methanolic solution. These unique features of the molecular rubies [Cr(ddpd)2]3+ and [Cr(H2tpda)2]3+ pave the way for highly sensitive optical pressure determination and unprecedented molecule‐based pressure sensing with a single type of emitter. 相似文献
912.
Jitka Zrostlikova Joe Binkley Petr Wojtowicz Tomas Adam 《Journal of Analytical Chemistry》2011,66(13):1333-1340
In this paper several characteristic features of time-of-flight mass spectrometry in coupling with gas chromatography are
demonstrated and the parameters are compared to quadrupole mass analyzer. In the second part, the comprehensive two-dimensional
gas chromatography coupled to time-of-flight mass spectrometry was applied in human metabolomic field, particularly in the
determination of pathological markers of Inherited Metabolic Disorders (IMDs). 相似文献
913.
Vasireddy S Ganguly S Sauer J Cook W Spivey JJ 《Chemical communications (Cambridge, England)》2011,47(2):785-787
The direct gas phase catalytic oligomerization of methane at temperatures ≤673 K has been demonstrated using AlBr(3)-HBr superacid. The reaction produces C(2)+ hydrocarbons and hydrogen in a single step at 1 atm in a continuous flow reactor at a nominal residence time of 60 s. The essentially complete conversion of methane appears to be due to protolytic activation of methane in the presence of H(+)AlBr(4)(-). 相似文献
914.
915.
Joe Cyr 《Algebra Universalis》2018,79(2):39
It is known that for finite algebras, solvable implies hereditarily absorption free. We present an example which shows that this implication does not hold for infinite algebras. This example is also quasi-affine, contradicting an earlier statement that quasi-affine algebras are hereditarily absorption free. 相似文献
916.
917.
Joe H. 《Journal of multivariate analysis》1993,46(2)
Parametric families of continuous bivariate distributions with given margins that include independence and perfect positive dependence are compared on the basis on some important properties. Since many such families exist, the comparisons are helpful for deciding on suitable models for multivariate data. The study of the properties has motivation from applications in extreme value inference. One property considered for bivariate families is whether they extend to multivariate families, and extensions are given when possible. Several new bivariate and multivariate families are included and some open research problems in the area of multivariate families are mentioned. 相似文献
918.
Analysis of glycopeptide antibiotics using micellar electrokinetic chromatography and borate complexation 总被引:1,自引:0,他引:1
Micellar electrokinetic chromatography (MEKC) was investigated as a technique for the separation and analysis of the following related glycopeptide antibiotics: alpha-avoparcin, beta-avoparcin, ristocetin A, ristocetin B and vancomycin. Sodium dodecyl sulfate (SDS) micelles were employed as the pseudostationary phase in conjunction with borate or CHES buffers at pH 9.2. A complete separation of the glycopeptides was achieved only when two separation mechanisms were employed simultaneously: (i) differential partitioning of the glycopeptides into SDS micelles; and (ii) differential complexation of the glycopeptides with the borate anion from the borate buffer. Quantitatively, linearity was confirmed for each antibiotic from 0.5 to 40 ppm, with correlation coefficients (r(2)) ranging from 0.9996 (vancomycin and beta-avoparcin) to 0.9986 (alpha-avoparcin). Detection limits ranging from 0.01 ppm (vancomycin) to 0.2 ppm (avoparcin) were achieved, and the mean recovery of avoparcin at the 10 ppm level was 99.2%. 相似文献
919.
Safa Almadhi Joe Forth Laura Rodriguez-Arco Aroa Duro-Castano Ian Williams Lorena Ruiz-Pérez Giuseppe Battaglia 《Macromolecular bioscience》2023,23(8):2300068
A bottom-up approach to fabricating monodisperse, two-component polymersomes that possess phase-separated (“patchy”) chemical topology is presented. This approach is compared with already-existing top-down preparation methods for patchy polymer vesicles, such as film rehydration. These findings demonstrate a bottom-up, solvent-switch self-assembly approach that produces a high yield of nanoparticles of the target size, morphology, and surface topology for drug delivery applications, in this case patchy polymersomes of a diameter of ≈50 nm. In addition, an image processing algorithm to automatically calculate polymersome size distributions from transmission electron microscope images based on a series of pre-processing steps, image segmentation, and round object identification is presented. 相似文献
920.
Xavier TS Joe IH 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,79(2):332-337
The Fourier-transform Raman and infrared spectra of 2-amino-5-fluoro benzoic acid has been recorded and analyzed. The optimized geometry of the other halogen substitution (Cl, Br) have been computed with the help of density functional theory. The detailed interpretation of vibrational spectra of 2-amino-5-fluoro benzoic acid have performed in terms of potential energy distribution analysis. Natural bond orbital analysis on 2-amino-5-fluoro benzoic acid, 2-amino-5-chloro benzoic acid and 2-amino-5-bromo benzoic acid has been carried out for various intramolecular interactions that are responsible for the stabilization of the molecule. The pKa values of 2-amino-5-fluoro benzoic acid, 2-amino-5-chloro benzoic acid and 2-amino-5-bromo benzoic acid are computed using MOPAC and it is related with HOMO-LUMO energy difference obtained from Gaussian 03 software. The biological activity of 2-amino-5-fluoro benzoic acid has been predicted based on these values. The inhibition activity of 2-amino-5-bromo benzoic acid with the protein tyrosine kinase 3LQ8 is simulated by using Autodock software. 相似文献