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991.
Jun-ichi Chikawa Masaichi Bandou Ken Tabuchi Katsuhiko Tani Hisashi Saji Yozo Takasaki 《Progress in Crystal Growth and Characterization of Materials》2019,65(3):100452
Concentrations of elements in single hair samples were evaluated by X-ray fluorescence by scanning with a narrow beam in the growth direction. Zn binds to the hair protein molecules, and is distributed uniformly from hair tip to root bulb by steady-state growth. To avoid the effect of thickness variation for the bulb, the hair elements were evaluated as the amount per protein molecule using the hair [Zn], resulting in the fault-bounded [S] change typical for a solid–liquid interface; the papilla is in a liquid state and the segregation of elements occurs so as to maintain the amount of shaft element equal to the element inflow into the papilla from the blood, leading to the relationship between hair and blood concentrations. The diffusion boundary layer of S segregation in the bulb gives the diffusion coefficient of D~1 × 10?8 cm2/s. The liquid papilla during hair growth solidifies with temperature decrease with the formation of the hair specimen, and the results for solidified papilla are different from the state during growth. It is proposed that the serum protein supplied into dermal papilla changes into precursor keratin molecules, and then into insolvable keratin in the hair matrix cells, i.e., hair makes “protein-melt growth.” The pulsed or stepwise variations of [Ca] and [Sr] occur due to the ion channel gating of matrix cells; such variations can never be expected for the cell division growth as deduced from the solidified papilla. The hair growth reflects the status of ion channels and pumping only possible because of the solid–liquid growth interface driven by the gradient in chemical potential nearly perpendicular to the skin surface. Thus, a hair root is a solid–liquid system for hair formation from serum protein. 相似文献
992.
A new method for detecting protein by synchronous fluorescence enhancement was developed, based on the combination of near infrared (NIR) fluorescence and the dedimerization phenomenon of methylene blue (MB). Under analytical conditions, there are linear relationships between the enhancing extent of synchronous fluorescence of MB-sodium dodecyl benzene sulfonate (SDBS)-protein at 667 nm and the concentration of protein in the range of 8.0 × 10−8-4.0 × 10−5 g mL−1 for bovine serum albumin (BSA), 1.0 × 10−7-3.5 × 10−5 g mL−1 for egg albumin (EA). The detection limits (S/N = 3) of BSA and EA are 8.9 ng mL−1 and 10.0 ng mL−1, respectively. The fluorescence enhancement mechanism is discussed in detail. Results from multiple techniques indicate that the fluorescence enhancement of the system originates from the hydrophobic microenvironment provided by BSA and SDBS, and the formation of an MB-SDBS-BSA complex, as well as the deaggregation of some MB dimer. 相似文献
993.
Comparison of magnetic resonance imaging of inhaled SF6 with respiratory gas analysis 总被引:1,自引:0,他引:1
Scholz AW Wolf U Fabel M Weiler N Heussel CP Eberle B David M Schreiber WG 《Magnetic resonance imaging》2009,27(4):549-556
Magnetic resonance imaging of inhaled fluorinated inert gases ((19)F-MRI) such as sulfur hexafluoride (SF(6)) allows for analysis of ventilated air spaces. In this study, the possibility of using this technique to image lung function was assessed. For this, (19)F-MRI of inhaled SF(6) was compared with respiratory gas analysis, which is a global but reliable measure of alveolar gas fraction. Five anesthetized pigs underwent multiple-breath wash-in procedures with a gas mixture of 70% SF(6) and 30% oxygen. Two-dimensional (19)F-MRI and end-expiratory gas fraction analysis were performed after 4 to 24 inhaled breaths. Signal intensity of (19)F-MRI and end-expiratory SF(6) fraction were evaluated with respect to linear correlation and reproducibility. Time constants were estimated by both MRI and respiratory gas analysis data and compared for agreement. A good linear correlation between signal intensity and end-expiratory gas fraction was found (correlation coefficient 0.99+/-0.01). The data were reproducible (standard error of signal intensity 8% vs. that of gas fraction 5%) and the comparison of time constants yielded a sufficient agreement. According to the good linear correlation and the acceptable reproducibility, we suggest the (19)F-MRI to be a valuable tool for quantification of intrapulmonary SF(6) and hence lung function. 相似文献
994.
《Molecular physics》2012,110(19-20):2523-2534
Data intense processes such as the establishment of quantitative structure–property relationships, the design of novel compounds and also the validation of new quantum chemical methods call for a structured approach for the processing of the results. Whereas in quantum chemistry there are established de facto standards for the computational methods, community standards for [exchange-] data formats are still under development. In this article we present a benchmark study of the (auxiliary-) basis set dependence of the binding energies of an array of conformers of the ethene dimer using the RI-MP2-F12 method. The study was performed using a version of the TURBOMOLE program package modified to provide output in an extended CML format to be imported in an eXist database. This infrastructure for the generation, archival, analysis, and exchange of quantum chemical data is briefly introduced in this article. 相似文献
995.
催化裂化装置(FCCU)是石油二次加工的重要手段,也是排放硫氧化物(SOx)的主要源头之一.据报道,炼油厂排放的SOx约占其总排放量的6%~7%,而催化裂化(FCC)就占总排放量的5%左右[1].催化裂化(FCC)过程中沉积在焦炭上的硫会转化为SOx(其中SO2占90%以上,其余为SO3),随再生烟气排出, 相似文献
996.
《Molecular physics》2012,110(21-22):2797-2805
Spectra of acetylene dimers and trimers containing one or more C2D2 monomer are studied in the ν3 fundamental band region of C2D2 (≈2440?cm?1) using a tuneable infrared diode laser to probe a pulsed supersonic slit jet expansion. Four new subbands are observed in the perpendicular band of (C2D2)2, and this enables the first direct determination of the A rotational constant for an acetylene dimer. The value found for A is significantly larger than the previous indirect value based on microwave spectra. The dimer parallel band is observed and found to be highly perturbed, and observations are extended for the mixed dimer C2D2 – C2H2. The trimers (C2D2)3, (C2D2)2 – C2H2, and C2D2 – (C2H2)2 are observed spectroscopically for the first time. Establishment of a precise band origin is difficult for (C2D2)3 because of the inherent nature of the spectrum, but this is possible for two out of three of the bands of the mixed trimers. 相似文献
997.
998.
999.
C. Meganathan S. Sebastian M. Kurt Keun Woo Lee N. Sundaraganesan 《Journal of Raman spectroscopy : JRS》2010,41(10):1369-1378
Vibrational spectral analysis was carried out for 4‐methoxy‐2‐methyl benzoic acid (4M2MBA) by using Fourier transform infrared (FT‐IR) (solid, gas phase) and FT‐Raman spectroscopy in the range of 400–4000 and 10–3500 cm−1 respectively. The effects of molecular association through O H···O hydrogen bonding have been described by the single dimer structure. The theoretical computational density functional theory (DFT) and Hatree‐Fock (HF) method were performed at 6–311++G(d,p) levels to derive the equilibrium geometry, vibrational wavenumbers, infrared intensities and Raman scattering activities. The scaled theoretical wavenumbers were also shown to be in good agreement with experimental data. The first‐order hyperpolarizability (β0) of this novel molecular system and related properties (β, α0 and Δα) of 4M2MBA are calculated using the B3LYP/cc‐pvdz basis set, based on the finite‐field approach. A detailed interpretation of the infrared and Raman spectra of 4M2MBA is reported. The theoretical spectrograms for FT‐IR and FT‐Raman spectra of the title molecule were also constructed and compared with the experimental one. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
1000.
Yong Wu Lu Jin Ying Xue Ik‐Mo Lee Chan Kyung Kim 《Journal of computational chemistry》2010,31(12):2248-2257
We investigated the transition metal‐catalyzed reaction mechanisms of NBD dimerization to Binor‐S using cationic CoI, RhI, and IrI catalysts, using mPW1PW91, mPW1K, and B3LYP density functional methods. Our results indicate that the monomeric metal center has the ability to bind with four double bonds of two NBD molecules with a syn spatial geometry to form a penta‐coordinated complex. We designed three possible pathways, but found two of them blocked. The favored pathway involves three steps from the reactant precursor to the product precursor: the first step is the formation of a single bond to connect two NBD units, the second is the alkene insertion leading to the formation of the three‐membered ring structure, and the final step is the formation of the final product precursor. Orbital analysis showed metal…C? C σ agostic interaction in the product precursor, which is in agreement with the previous experimental findings. In addition, we found that the solvent and counter‐ions had significant effects on the dimerization reactions. © 2010 Wiley Periodicals, Inc. J Comput Chem 2010 相似文献