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11.
Z. P. Lu L. Stachowicz P. Kong J. Heberlein E. Pfender 《Plasma Chemistry and Plasma Processing》1991,11(3):387-394
Diamond crystals and films have been success full y synthesized by DC thermal plasma jet CVD at a pressure of I atrn. A novel triple torch plasma reactor has been used to generate a convergent plasma volume to entrain the participating gases. Three coalescing plasma jets produces! by this reactor direct the dissociated and ionized gaseous species onto ( 100) silicon wafer substrates where the diamond grows. In a typical 10-min run, depending on the method of .substrate preparation, either microcrystals with sizes up to 8 m or continuous films with thicknesses of 1–2 m have been obtained. X-ray diffraction, scanning electron microscopy, and Raman spectroscopy have been used for the characterization of the crystals and of the films. 相似文献
12.
A precursor of Ce0.8Y0.2O1.9(YDC) solid electrolyte was synthesized by the gol-gel method. YDC and phosphates powders were prepared by mixing the YDC and phosphates according to different weight ratios. The mixtures of the YDC and binary phosphates were ground and sintered at 1 400 ℃. The proton conductivity in solid electrolyte of the sintered samples was examined using electrochemical methods at 400~800 ℃. Ammonia was synthesized from nitrogen and hydrogen at atmospheric pressure in the solid state proton conducting cell reactor. The optimal condition for the ammonia production was determined. The result indicated that composite electrolyte of 80wt% YDC: 20wt% binary phosphates as proton conductor could obtain the highest ionic conductivity and ammonia production rate among the four samples, the rate of evolution of ammonia was up to 9.5 × 10-9 mol·s-1·cm-2. 相似文献
13.
A delayed coincidence method, time-interval analysis (TIA), has been applied to successive – decay events on the millisecond time-scale. Such decay events are part of the 220Rn216Po (T1/2 145 ms) (Th-series) and 219Rn215Po (T1/2 1.78 ms) (Ac-series). By using TIA in addition to measurement of 226Ra (U-series) from -spectrometry by liquid scintillation counting (LSC), two natural decay series could be identified and separated. The TIA detection efficiency was improved by using the pulse-shape discrimination technique (PSD) to reject -pulses, by solvent extraction of Ra combined with simple chemical separation, and by purging the scintillation solution with dry N2 gas. The U- and Th-series together with the Ac-series were determined, respectively, from alpha spectra and TIA carried out immediately after Ra-extraction. Using the 221Fr217At (T1/2 32.3 ms) decay process as a tracer, overall yields were estimated from application of TIA to the 225Ra (Np-decay series) at the time of maximum growth. The present method has proven useful for simultaneous determination of three radioactive decay series in environmental samples. 相似文献
14.
《Surface and interface analysis : SIA》2004,36(4):339-346
Air‐formed oxide on a CuAl2 model alloy is shown to be free of copper species, with copper enriching in the alloy. With thickening of the oxide by anodizing, copper enriches further to a critical concentration at which its oxidation proceeds with incorporation of Cu(II) species into the film. Such species migrate more rapidly through the film than aluminium species. Incorporation of copper species is associated with generation of oxygen gas within the film and subsequent film rupture is due to release of the gas. Reduction of Cu(II) to Cu(I) species during XPS analysis is characterized and the accelerating role of charge neutralizing is highlighted. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
15.
Summary A new, highly sensitive and selective gas chromatography method, using radiochemical detection (GC-DR) was developed for the
selective determination of3H-labelled deramciclane and its N-desmethyl metabolite in dog plasma. Inter-day accuracy and precision, as well as system
suitability of the GC-RD method was investigated during the method validation. The calibration curve was proved to be linear
(r=0.9986) in a wide concentration range (13–1000 ngeqv mL−1)
The lower limit of quantitation (LLOQ) was 13.7 ngeqv mL−1, and the limit of the detection (LOD) was 1 ngeqv mL−1.
Using this new GC-RD method, plasma levels of3H-labelled deramciclane and its metabolite were determined in dogs, after the administration of a single 10 mg kg−1 oral dose. Pharmacokinetic curves and the calculated pharmacokinetic parameters were compared to those obtained using a previously
elaborated gas chromatography-nitrogen selective detection method (GC-NPD) and to those obtained by measuring the plasma level
of total radioactivity (liquid scintillation counting, LSC). Pharmacokinetic curves and the calculated pharmacokinetic parameters
obtained with the two different gas chromatography detection methods (NPD and RD) showed good correlation. Comparison of these
results to those acquired by total radioactivity measurement demonstrated that deramciclane was intensively metabolised. Moreover,
the biological half-life (t
1
2/β
) of the unknown metabolites proved to be more than a magnitude longer than the half-life of the parent compound or that of
N-desmethyl metabolite.
Presented at: Balaton Symposium on High-Performance Separation Methods, Siófok, Hungary, September 3–5, 1997. 相似文献
16.
Shihai You Tingting Zhu Yumin Wang Zeng-Kui Zhu Zhongyuan Li Jianbo Wu Panpan Yu Lina Li Chengmin Ji Yaxing Wang Shuao Wang Junhua Luo 《Advanced functional materials》2023,33(9):2210481
The exceptional photophysical properties of 3D organic–inorganic lead halide hybrids (OILHs) endow their significant potential for usage in optoelectronics, which has sparked intense research on novel 3D OILHs and associated applications. However, constructing new 3D OILHs based on large organic cations suffers from tough challenges due to the limitation of the Goldschmidt tolerance factor rule, let alone further explorations of their practical applications. Herein, a brand-new 3D lead chloride hybrid, (1MPZ)Pb4Cl10·H2O ( 1 , 1MPZ = 1-methylpiperazine) is reported, featuring a dense 3D lead chloride framework made of the corner-, edge-, and face-shared lead chloride polyhedra. 1 presents a broadband white light emission with a large Stokes shift and a nanosecond photoluminescence lifetime, which originates from radiative recombination of self-trapped excitons (STEs) induced by the highly distorted structure. Such a reabsorption-free and fast-decayed STEs emission coupling with the dense 3D architecture further enables 1 with effective X-ray scintillation with good sensitivity. Impressively, 1 also shows superior environmental and radiation stability. This study provides a new 3D OILH with appealing luminescence, not only expanding the 3D OILH family but also inspiring the exploitation of their optoelectronic applications. 相似文献
17.
C. Hemanth R. G. Sangeetha Ishu Jaiswal 《International Journal of Communication Systems》2023,36(10):e5497
This paper investigates the performance of a dual-hop mixed relay system with radio frequency (RF) and free-space optics (FSO) communication under the effect of pointing error (PE) and atmospheric turbulence (AT). This paper considers a system where RF and FSO links are cascaded. The RF link is modeled by Nakagami-m fading, and the FSO link is modeled as gamma–gamma (G-G) fading channel. Both the channel models use orthogonal frequency division multiplexing (OFDM) with M-ary quadrature amplitude modulation (QAM). The expressions for probability density function, cumulative distribution function, signal-to-noise ratio, and ergodic capacity are derived. The moment generating function (MGF) of fading and the bit error rate (BER) of the OFDM-based M-ary QAM scheme is derived in terms of Meijer's G-function. It has been observed that, in fixed gain relay systems, the modulation scheme's BER is dominated by the SNR of the RF link. While in a variable gain relay system, the turbulence conditions of the FSO system affect the SNR and the BER of the modulation method. The feasibility of heterodyne detection and intensity modulation direct detection (IM/DD) is analyzed in terms of outage probability and ergodic capacity. The results can be used to choose the optimal modulation order and relay system for QAM-OFDM-based optical wireless systems. 相似文献
18.
19.
Durry G Amarouche N Zéninari V Parvitte B Lebarbu T Ovarlez J 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2004,60(14):805-3379
Since 1997, two near-infrared laser diode sensors have been developed with the support of the CNES, the French space agency, to provide in situ data of H(2)O, CH(4) and CO(2) in the middle atmosphere. The realized instruments were flown from stratospheric balloons within the framework of European campaigns for the study of stratospheric ozone and water vapor and were involved in the validation of the ODIN and ENVISAT satellites. In this paper, we describe the developed laser probing technique, we report atmospheric measurements and finally we discuss future perspectives, particularly the in situ laser sensing of the lower atmosphere of Mars and the implication of the laser hygrometers in balloon campaigns at mid-latitudes and tropical regions to investigate the sources and sinks of stratospheric H(2)O. 相似文献
20.
OH and HO(2) radicals, atmospheric detergents, and the reservoir thereof, play central roles in tropospheric chemistry. In spite of their importance, we had no choice but to trust their concentrations predicted by modeling studies based on known chemical processes. However, recent direct measurements of these radicals have enabled us to test and revise our knowledge of the processes by comparing the predicted and observed values of the radical concentrations. We developed a laser-induced fluorescence (LIF) instrument and successfully observed OH and HO(2) at three remote islands of Japan (Oki Island, Okinawa Island, and Rishiri Island). At Okinawa Island, the observed daytime level of HO(2) agreed closely with the model estimates, suggesting that the photochemistry at Okinawa is well described by the current chemistry mechanism. At Rishiri Island, in contrast, the observed daytime level of HO(2) was consistently much lower than the calculated values. We proposed that iodine chemistry, usually not incorporated into the mechanism, is at least partly responsible for the discrepancy in the results. At night, HO(2) was detected at levels greater than 1 pptv at all three islands, suggesting the presence of processes in the dark that produce radicals. We showed that ozone reactions with unsaturated hydrocarbons, including monoterpenes, could significantly contribute to radical production. 相似文献