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1.
本文设计了一种梯形的周期极化掺镁铌酸锂(PPMgLN)波导,并通过在传播方向上引入温度梯度来拓宽其倍频(SHG)过程的泵浦光源可接收带宽。通过有限差分的光束传输法,计算波导的有效折射率,并进行波导尺寸的设计。结果表明,通过改变梯形波导不同位置的温度,使其形成一个温度梯度,可拓宽泵浦光源的波长可接收带宽。本文所设计的PPMgLN波导最大泵浦光源可接收带宽为C波段,即1 530~1 565 nm,该波导可倍频C波段,得到输出波段带宽为765~782.5 nm,温度调谐范围为30~150 ℃。 相似文献
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Kellie R. England Dr. Sang Ho Lim Lucy M. C. Luong Prof. Marilyn M. Olmstead Prof. Alan L. Balch 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(3):874-878
The mono- and di-chloroform solvates of [Au2(μ-1,2-bis(diphenylarsino)ethane)2](AsF6)2 undergo single-crystal-to-single-crystal transformations that result in gain (over 12 hours) or slow loss (over five years) of only one chloroform molecule. The change in solvation results in changes in the structure and luminescence of the digold cation. The cation consists of a pair of slightly bent As-Au-As units that are connected through the two bridging dpae ligands and by aurophilic interactions with Au⋅⋅⋅Au contacts of 3.05152(15) Å in the disolvate or 2.9570(5) Å in the monosolvate. 相似文献
4.
Hongjuan Chen Peng Fan Xingxin Tu Hui Min Xianyong Yu Xiaofang Li Ju‐Lan Zeng Shaowei Zhang Peng Cheng 《化学:亚洲杂志》2019,14(20):3611-3619
The hydrothermal reaction of Zn2+ ions with a mixture of two ligands, Hcptpy and H3btc (Hcptpy=4‐(4‐carboxyphenyl)‐2,2′:4′,4′′‐terpyridine; H3btc=1,3,5‐benzenetricarboxylic acid), led to the formation of a 3D metal–organic framework (MOF) with 1D channels, [Zn2(cptpy)(btc)(H2O)]n ( 1 ), which was structurally characterized by using single‐crystal X‐ray diffraction (SXRD). In MOF 1 , two independent Zn2+ ions were interconnected by btc3? ligands to form a 1D chain, whilst adjacent Zn2+ ions were alternately bridged by cptpy? ligands to generate a 2D sheet, which was further linked by 1D chains to form a 3D framework with a new (3,3,4,4)‐connected topology. Furthermore, compound 1 also exhibited excellent stability towards air and water and, more importantly, luminescence experiments indicated that it could serve as a probe for the sensitive detection of paraquat (PAQ) and Fe3+ ions in aqueous solution. 相似文献
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Dr. Xiang-Yang Liu Yi-Jie Zhang Xiyu Fei Prof. Man-Keung Fung Prof. Jian Fan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(27):6788-6796
Spirocyclic compounds such as 9,9′-spirobifluorene (SBF) are becoming more and more attractive for use as host materials in organic optoelectronic devices. Herein, two dispirocycles, namely, dispiro[fluorene-9,9′-anthracene-10′,9′′-fluorene] and 10,10′′-diphenyl-10H,10′′H-dispiro[acridine-9,9′-anthracene-10′,9′′-acridine], were used for the construction of host materials 1 – 4 . The attached triphenylamino group determines the thermal, photophysical, electrochemical, and charge-transport properties, and therefore they have different electroluminescent performances. The device based on dispiro[fluorene-9,9′-anthracene-10′,9′′-fluorene] ( 2 ) and 10,10′′-diphenyl-10H,10′′H-dispiro[acridine-9,9′-anthracene-10′,9′′-acridine] ( 3 ) molecular platforms exhibited external quantum efficiencies of greater than 21 % with a very high power efficiency (≈100 lm W−1). These results demonstrate the potential of extending the application of dispirocyclic molecular platforms with inherent rigidity for developing highly efficient host materials for organic light-emitting diodes. 相似文献
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Rui-Juan Zhang Jian-Chao Shi Dan-Dan Zhao Xiao-Yang Han Ling Deng Xiao-Qi Cui Dan Zhao 《Acta Crystallographica. Section C, Structural Chemistry》2019,75(11):1494-1501
A new potassium dysprosium polyborate, K3DyB6O12, has been prepared via the high‐temperature molten salt method and structurally characterized by single‐crystal X‐ray diffraction analysis. The structure can be described as a three‐dimensional framework composed of isolated bicyclic [B5O10]5? groups and Dy3+ and K+ ions. The Fourier transform IR (FT–IR) and ultraviolet–visible (UV–Vis) spectra were investigated. A series of K3Gd1–xDyxB6O12 phosphors was prepared and their photoluminescence properties were studied. The K3Gd1–xDyxB6O12 phosphors exhibit a strong yellow emission band at 577 nm (the 4F9/2→6H13/2 transition of Dy3+) under UV excitation of 275 nm (the 8S7/2→6IJ transition of Gd3+), suggesting the occurrence of the energy transfer Gd3+→Dy3+. The optimized doping concentration of the Dy3+ ion was 8 mol%. We may expect that K3Gd1–xDyxB6O12 is a promising pale‐yellow emission phosphor for visual displays or solid‐state lighting. 相似文献
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Lana K. Hiscock Brooke M. Raycraft Monika Wałęsa-Chorab Coralie Cambe Alexandre Malinge Prof. Dr. W. G. Skene Hi Taing Prof. Dr. S. Holger Eichhorn Prof. Dr. Louise N. Dawe Prof. Dr. Kenneth E. Maly 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(4):1018-1028
A series of new tetrakis(dialkoxyphenyl) dicyanotetraoxapentacene derivatives ( 1 a – c ) were prepared by reaction of the appropriate terphenyl diols with tetrafluoroterephthalonitrile in good yields. Compounds 1 b and 1 c , which bear hexyloxy and decyloxy side chains, exhibited columnar hexagonal mesophases, as shown by polarized optical microscopy, variable-temperature powder X-ray diffraction, and differential scanning calorimetry. Single-crystal X-ray diffraction of methoxy-substituted 1 a revealed that the dicyanotetraoxapentacene core is highly planar, consistent with the notion that these molecules are able to stack in columnar mesophases. A detailed photophysical characterization showed that these compounds exhibit aggregation-induced emission in solution, emission in nonpolar solvents, weak emission in polar solvents, and strong emission in the solid state both as powder and in thin films. These observations are consistent with a weakly emissive charge-transfer state in polar solvents and a more highly emissive locally excited state in nonpolar solvents. 相似文献
10.
利用高温固相法成功制备了Er~(3+)单掺、Er~(3+)/Yb~(3+)共掺杂Ca_(12)Al_(14)O_(32)F_2上转换发光样品。在980 nm激光激发下,Er~(3+)单掺和Er~(3+)/Yb~(3+)共掺杂样品均呈现出较强的绿光(528,549 nm)和较弱的红光(655 nm)发射,分别归因于Er~(3+)离子的~2H_(11/2),~4S_(3/2)→~4I_(15/2)和~4F_(9/2)→~4I_(15/2)能级跃迁。随着Er离子浓度的增加,单掺杂样品上转换发光强度先增大后减小,最佳掺杂浓度为0.8%。共掺杂Yb~(3+)后,Er~(3+)的发光强度明显增大。还原气氛下合成的样品上转换发光强度增大约两倍,可能和笼中阴离子基团变化有关。发光强度和激发光功率的关系表明所得上转换发射为双光子吸收过程,借助Er~(3+)-Yb~(3+)体系能级结构详细讨论了上转换发射的跃迁机制。 相似文献