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961.
New 4H silicon carbide metal semiconductor field-effect transistor with a buffer layer between the gate and the channel layer 下载免费PDF全文
A new 4H silicon carbide metal semiconductor field-effect transistor (4H-SiC MESFET) structure with a buffer layer between the gate and the channel layer is proposed in this paper for high power microwave applications.The physics-based analytical models for calculating the performance of the proposed device are obtained by solving one-and two-dimensional Poisson’s equations.In the models,we take into account not only two regions under the gate but also a third high field region between the gate and the drain which is usually omitted.The direct-current and the alternatingcurrent performances for the proposed 4H-SiC MESFET with a buffer layer of 0.2 μm are calculated.The calculated results are in good agreement with the experimental data.The current is larger than that of the conventional structure.The cutoff frequency (fT) and the maximum oscillation frequency (f max) are 20.4 GHz and 101.6 GHz,respectively,which are higher than 7.8 GHz and 45.3 GHz of the conventional structure.Therefore,the proposed 4H-SiC MESFET structure has better power and microwave performances than the conventional structure. 相似文献
962.
报道了一种基于非线性放大环镜和Lyot滤波器技术的态开关型掺铥光纤激光器.通过仔细调节偏振控制器和泵浦功率,掺铥光纤激光器可以分别在多波长态和耗散孤子锁模态运行,并且两种态之间可以相互切换.对于多波长态,在光谱半功率值范围内能生成8个稳定的波长;对于耗散孤子锁模态,在1996 nm的中心波长处产生脉冲能量高达41.49 nJ,脉冲持续时间为2.4 ns,光谱带宽为29 nm的耗散孤子.不同运行态间的切换归因于偏振控制器导致的非线性放大环镜的功能的改变. 相似文献
963.
《Surface and interface analysis : SIA》2018,50(6):623-627
The electronic structures of Alq3/Si(100), Alq3/LiBr/Si(100), and Alq3/KCl/Si(100) systems are presented in this report. Their energy level diagrams were prepared and discussed. The formation of the LiBr and KCl interfacial layers between an Alq3 film and a Si(100) substrate results in a decrease of the energy barrier at the interface. The studies were carried out in situ in ultrahigh vacuum by ultraviolet photoelectron spectroscopy. Alq3 as well as LiBr and KCl layers were vapour evaporated onto n‐type Si(100) crystal. The electron affinity of clean Si(100) surface was 4.0 eV, and the position of the valence band maximum was 0.7 eV below EF. The energetic distance between the valence band maximum of Si(100) and the highest occupied molecular orbital level were 1.5, 2.6, and 2.2 eV, for the Alq3/Si(100), Alq3/LiBr/Si(100), and Alq3/KCl/Si(100) systems, respectively. 相似文献
964.
Osamu Wada 《光学与光电技术》2015,13(1):5-8
首先对未来系统光子器件的关键问题进行了综述。并且对半导体纳米结构,特别是基于量子点材料的超快开关器件取得的最新进展进行了讨论。其中包括基于量子点的半导体光放大器,其在超过40Gb/s的速率下展现出偏振不敏感特性;新型基于量子点的垂直腔结构的光开关,其展现出超快、节能、全光开关的特性。概括和讨论了未来基于纳米结构的光子器件的应用。 相似文献
965.
Synthesis and Characterization of a Helicene‐Based Imidazolium Salt and Its Application in Organic Molecular Electronics 下载免费PDF全文
Dr. Jan Storch Dr. Jaroslav Zadny Dr. Tomas Strasak Prof. Dr. Martin Kubala Dr. Jan Sykora Dr. Michal Dusek Dr. Vladimir Cirkva Prof. Dr. Pavel Matejka Dr. Milos Krbal Prof. Dr. Jan Vacek 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(6):2343-2347
Herein we demonstrate the synthesis of a helicene‐based imidazolium salt. The salt was prepared by starting from racemic 2‐methyl[6]helicene, which undergoes radical bromination to yield 2‐(bromomethyl)[6]helicene. Subsequent treatment with 1‐butylimidazole leads to the corresponding salt 1‐butyl‐3‐(2‐methyl[6]helicenyl)‐imidazolium bromide. The prepared salt was subsequently characterized by using NMR spectroscopy and X‐ray analysis, various optical spectrometric techniques, and computational chemistry tools. Finally, the imidazolium salt was immobilized onto a SiO2 substrate as a crystalline or amorphous deposit. The deposited layers were used for the development of organic molecular semiconductor devices and the construction of a fully reversible humidity sensor. 相似文献
966.
967.
The spectroscopy in the vicinity of the N=Z line at ISOLDE is reviewed. New data on the Gamow–Teller strength properties in
the A=60–80 region have been obtained. These data provide an insight to nuclear deformation, level densities and mirror β-decay,
and can be used to model and test astrophysical predictions in the region of the expected termination of the rp-process.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
968.
Nanoparticles of EuS were synthesized using europium dithiocarbamate complexes. The resulting nanoparticles were coated with the dye, 1-pyrene carboxylic acid and the resulting material was characterized using X-ray powder diffraction, TEM, and UV-visible spectroscopy. Fluorescence spectroscopy was used to determine the relative energy of the conduction band edge to the excited state energy of the dye. 相似文献
969.
The theoretical study published on Zhang et al. (2018) [8] has predicted that Hg2CuTi-type Ti2VSb is a fully compensated ferrimagnetic semiconductor. In this work, the effect of the anti-site disorder and the tetragonal distortion on the electronic structure of Ti2VSb has been investigated using first-principles calculations. The calculated results indicate that the fully compensated ferrimagnetic semiconductor (FCFS) property of Ti2VSb is sensitive to the tetragonal distortion and FCFS property can be maintained only when the c/a ratio is in the range of 0.95–1.04. When the c/a ratio is not in this range, Ti2VSb is firstly transformed into a fully compensated ferrimagnetic half metal and then gradually transformed into a normal ferrimagnetic metal. And it becomes a nearly fully compensated ferrimagnetic spin-gapless semiconductor when 25% content of Ti(A) atoms exchange their place with V atoms. 相似文献
970.
YAO Minyu ZHANG Jianfeng WU Jian CHEN Minghua WANG Dapeng LOU Caiyun GAO Yizhi ZHOU Bingkun 《中国光学快报(英文版)》1999,8(4)
It is presented the experiment of all-optical demultiplexing of one 2.5 Gb/s channel from an 8×2.5 Gb/s OTDM data stream using nonlinear optical loop morror with 3 km dispersion shifted fiber. Bit error rate (BER) of the demultiplexed channel is measured. A BER of 10-11 is achieved and the power penalty is only 1.4 dB when BER is 10-9. 相似文献