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101.
A. V. Gur'yanov M. I. Samoilovich M. Yu. Tsvetkov E. B. Intyushin Yu. I. Chigirinskii 《Journal of Applied Spectroscopy》2003,70(2):323-325
We carried out a comparative investigation of the photoluminescence of Er3+ ions in tellurite glasses on melted quartz substrates and when introduced into the matrices of artificial opal. We have discovered an increase in the photoluminescence of the opal–tellurite glass–Er3+ nanocomposite in comparison with the specimens of the same glass on melted quartz substrates. 相似文献
102.
针对采用锁相环和倍频器构造同步电路的ZX5、ZL5秒列可迭硅焊接电源,在实际应用中需要辨别相序接入市电的缺点,分析了原因,给出了无需分相序接入的改进方案,并从实验结果验证了方案的正确性。 相似文献
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J. W. Hofstraat M. P. Oude Wolbers F. C. J. M. van Veggel D. N. Reinhoudt M. H. V. Werts J. W. Verhoeven 《Journal of fluorescence》1998,8(4):301-308
Rare earth ions, with relatively long luminescence lifetimes, have significant advantages for application in fields as varied as diagnostics and optical amplification. In diagnostics the long luminescence lifetimes allow for extremely sensitive time-gated detection, where the difference in temporal behavior of scatter and background fluorescence and the long-lived rare earth luminescence is utilized. In optical amplification the long excited-state lifetime makes it easier to obtain population inversion, a requirement for effective stimulated emission. Unfortunately the absorption cross section of rare earth ion transitions is extremely low. However, via sensitized excitation by means of a suitable organic molecule, efficient excitation is obtained. It is shown that excitation in the visible part of the spectrum can be used to excite rare earth ions which luminesce in the near-IR, such as ytterbium, neodymium, and erbium, via a fluorescein-derivative as sensitizer. The advantages of this approach are manifold. Low-cost light sources are available for the visible part of the spectrum, and interferences from the matrix (scatter, absorption) are minimal. Detection in the near-IR is almost interference-free. For optical amplification the wavelength regions around 1300 and 1550 nm, which can be covered with the neodymium and erbium complexes, respectively, are the most important for applications in optical telecommunication. 相似文献
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1 Introduction Wavelength tunableultra shortopticalpulsesourcesareattractinggreatinterestforavarietyofapplications,suchasopticalfibersensors,wavelength divisionmultiplexingcommunicationsystemandtime resolvedspectroscopy .Ingeneral,wavelengthtuningisreali… 相似文献
108.
使用溶胶-凝胶法制备了Er3+单掺及Er3+/Yb3+共掺La2TiO5荧光粉体样品。经过1 100 ℃下3 h的煅烧,得到了较好的微晶。X射线粉末衍射测试表明样品中不含杂质相。扫描电镜观察表明样品颗粒范围为100~300 nm。紫外激发光谱中,在250~320 nm范围内出现Er离子和临近配位氧离子之间强烈的电荷转移跃迁峰,在350~500 nm出现Er离子f-f跃迁尖锐的吸收峰。在378 nm激发下,Er离子发射强烈的特征绿光(546 nm, 4S3/2-4I15/2),当Er离子物质的量分数达到1%,发射峰强度达到最大。在980 nm激发下的上转换光谱中,Yb离子的共掺杂有效的敏化上转换发光强度。详细讨论了样品的上下转换发光机理及相应能量传递过程。同时测试了样品的荧光衰减和量子产率。 相似文献
109.
Shufang Ji Prof. Yang Qu Dr. Tao Wang Yuanjun Chen Prof. Guofeng Wang Xue Li Dr. Juncai Dong QiuYu Chen Wanying Zhang Zedong Zhang Shiyou Liang Prof. Rong Yu Dr. Yu Wang Prof. Dingsheng Wang Prof. Yadong Li 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(26):10738-10744
The solar-driven photocatalytic reduction of CO2 (CO2RR) into chemical fuels is a promising route to enrich energy supplies and mitigate CO2 emissions. However, low catalytic efficiency and poor selectivity, especially in a pure-water system, hinder the development of photocatalytic CO2RR owing to the lack of effective catalysts. Herein, we report a novel atom-confinement and coordination (ACC) strategy to achieve the synthesis of rare-earth single erbium (Er) atoms supported on carbon nitride nanotubes (Er1/CN-NT) with a tunable dispersion density of single atoms. Er1/CN-NT is a highly efficient and robust photocatalyst that exhibits outstanding CO2RR performance in a pure-water system. Experimental results and density functional theory calculations reveal the crucial role of single Er atoms in promoting photocatalytic CO2RR. 相似文献
110.
Stanislav O. Konorov H. Georg Schulze Christopher J. Addison Charles A. Haynes Michael W. Blades Robin F. B. Turner 《Journal of Raman spectroscopy : JRS》2009,40(9):1162-1171
We report here the first UV resonance Raman spectroscopic (UVRRS) study on locked nucleic acid (LNA) oligomers. Locking a base in nucleic acid (NA) oligomers produces a conformational change in the glycosyl bond between backbone and base. We present evidence of this change in LNAs when compared to their natural analogs using UVRRS. Wavenumber downshifts and peak amplitude increases, especially of the ∼1481 cm−1 peak that is a spectral marker for part of the glycosyl bond, correlate with the fraction of locked bases when single‐stranded oligomers incorporating up to three locked bases were examined. By varying the position of the locked base within a fixed length sequence, we conclude that one, or at most two bases, on either side of the lock is affected. We further conclude from these data, and previously published reports, that the conformation of LNA is determined by imidazole–imidazole and pyrimidine–pyrimidine repulsion and imidazole–pyrimidine attraction in contrast to dispersion attraction‐dependent aggregation in the B conformation of DNA. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献