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131.
合成了6种氨基酸水杨醛席夫碱(Sal-AA):Sal-Gly(甘氨酸)、Sal-Phe(苯丙氨酸)、Sal-Arg(精氨酸)、Sal-Tyr(酪氨酸)、Sal-Met(甲硫氨酸)、Sal-Glu(谷氨酸)及其金属铜配合物。并分别在2种不同介质(三氯甲烷和甲醇)中,与四苯基卟啉TPP进行反应,研究了其紫外可见光谱性质,讨论了卟啉作为人工信号转导体系的传递介质,与氨基酸水杨醛席夫碱铜配合物的反应中,实现信号分子铜离子进一步传递的可能性以及溶剂对该信号传递的影响。结果表明,在三氯甲烷为溶剂时,除了Sal-Met的铜配合物之外,其余均能被TPP夺取而形成Metal TPP。而在以甲醇为溶剂时,只有Sal-Gly的铜配合物能被TPP所夺取。 相似文献
132.
Impedance biosensors are a class of electrical biosensors that show promise for point-of-care and other applications due to low cost, ease of miniaturization, and label-free operation. Unlabeled DNA and protein targets can be detected by monitoring changes in surface impedance when a target molecule binds to an immobilized probe. The affinity capture step leads to challenges shared by all label-free affinity biosensors; these challenges are discussed along with others unique to impedance readout. Various possible mechanisms for impedance change upon target binding are discussed. We critically summarize accomplishments of past label-free impedance biosensors and identify areas for future research. 相似文献
133.
Summary A detector for microchromatography in which Raman spectroscopy is used to identify the eluted species has been developed.
The detector is designed to be applicable to a wide range of compounds without requiring the presence of a chromophore. Its
use is illustrated in the analysis of nitro compounds on a 250 μm i.d. column. Raman spectra of each of the compounds could
be identified as they passed the detector. The advatages of the use of fully deuterated solvents are demonstrated by the analysis
of nitrobenzenes in methanol/water mobile phases. The detection limit for nitrobenzene using the Raman line at 1342 cm−1 was 75ng. 相似文献
134.
The semiconductor properties of the interface TiO2/electrolyte in high organized porous oxide structures were analyzed by means of impedance spectroscopy near the flat band
potential. The impedance and capacitance studies performed on the as-anodized and thermally treated samples (anatase) indicate
the presence of a duplex structure formed by (1) the oxide at the bottom of the pores and (2) the walls of pores with different
donor densities and surface state concentrations. 相似文献
135.
U. K. Chakrabarti S. J. Pearton W. S. Hobson C. R. Abernathy 《Plasma Chemistry and Plasma Processing》1993,13(2):333-350
Vinyl iodide (C2H3I) microwave discharges with additions of H2 and Ar are found to provide faster etch rates than conventional CH4/H2/Ar discharges for InP, InGaAs, GaAs, and AlGaAs. This is a result of the relatively high volatilities of indium, gallium, and aluminum iodide species. The etched features are smooth and anisotropic over a wide range of do self-biases (–150 to –350 V), process pressures (1–20mTorr), and microwave powers (150–500 W). The polymer that forms on the mask during the plasma exposure can be readily removed in O2 discharges. Electron spectroscopy for chemical analysis (ESCA) showed that the etched surfaces are slightly deficient in the group V elements under most conditions, but changes to the optical properties of the semiconductors are minimal. No defects are visible by transmission electron microscopy (TEM) in GaAs or InP samples etched at dc biases –250 V. 相似文献
136.
137.
An accurate primary Fourier transform infrared (FTIR) method for the determination of moisture in mineral and ester based lubricants has been developed based on the extraction of moisture into dry acetonitrile. FTIR evaluation of acetonitrile extracts from new and used lubricants as well as common lubricant additives and contaminants which might co-extract indicated that phenolic constituents interfered significantly with moisture measurements. By measuring moisture at 3676 cm−1 on the shoulder of the asymmetric OH stretching band, spectral interferences from extracted phenolic constituents were minimized. The spectra of calibration standards (0-2100 ppm), prepared by gravimetric addition of water to dry acetonitrile, were recorded in a 1000-μm CaF2 transmission flow cell and produced linear standard curves having an S.D. of ∼±20 ppm. Lubricant sample preparation involved the vigorous shaking (20 min) of a 1:1.5 (w/v) mixture of lubricant and dry acetonitrile, centrifugation to separate the phases, acquisition of the FTIR spectrum of the upper acetonitrile layer, and subtraction of the spectrum of the dry acetonitrile used for extraction. A Continuous Oil Analyzer and Treatment (COAT®) FTIR system was programmed to allow the automated analysis of acetonitrile extracts, and the methodology was validated by analyzing 58 new and used oils, independently analyzed by the Karl Fischer (KF) method. Linear regression of FTIR versus KF results for these oils produced a linear plot with a between-method S.D. of ±80 ppm. As implemented on the COAT® system, this FTIR method is capable of analyzing 72 acetonitrile extracts/h and provides a high-speed alternative to the KF titrimetric procedures for the determination of water in lubricants. 相似文献
138.
Photoacoustic spectroscopy of solids and surfaces 总被引:1,自引:0,他引:1
After briefly reviewing the theory and instrumentation, results from a variety of experiments carried out by the authors on
the photoacoustic spectroscopy of solids and surfaces by employing an indigenous spectrometer are discussed in the light of
the recent literature. Some of the important findings discussed are, phase angle spectroscopy, anomalous behaviour of monolayers,
unusual frequency dependence in small cell volumes, spectra of a variety of solids including amorphous arsenic chalcogenides,
photoacoustic detection of phase transitions and determination of surface areas and surface acidities of oxides. Recent developments
such as piezoelectric photoacoustic spectroscopy, depth profiling and subsurface imaging are also presented.
Contribution No. 124 from the Solid State and Structural Chemistry Unit. 相似文献
139.
P. V
orek P. indel E. ernokov J. Hole
ek 《Journal of polymer science. Part A, Polymer chemistry》1993,31(12):2923-2928
The ternary catalyst systems based on activated silica, aluminum alkyl, and titanium tetrachloride were polymerized in an ethylene gas-phase polymerization process, and further studied using ESR spectroscopy. Two types of titanium (III) ESR-active centers were observed and a linear dependence between the concentration of that characterized by a rhombic anisotropic signal with g1 = 1.962, g2 = 1.945, and g3 = 1.913 values and catalyst productivity was found. © 1993 John Wiley & Sons, Inc. 相似文献
140.
Jian X. Gao Jian C. Wang Chong L. Song T. Liu Tian D. Hu Ya N. Xie J. Zhang G. Wang H. Yang 《Journal of solution chemistry》2006,35(1):113-119
NMR spectroscopy was used to show that the symmetry of the crown ether bis(C6) is increased by an increase of the alkali metal
cation radius. The EXAFS spectrum demonstrates that a seven oxygen atom coordinated configuration is present in the bis(C6)/Cs+/NPME system, where NPME denotes o-nitrophenylmethyl ether. The seventh oxygen in this complex, besides the six crown ether oxygens of bis(C6), may come either
from a H2O molecule or an NO3− ion. 相似文献