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871.
实现同步轨道(GEO)高分辨力对地观测的技术途径(上) 总被引:2,自引:0,他引:2
在地球静止同步轨道(GEO)上实现高分辨力对地观测,具有一系列独特优点,远为其它轨道所不及。然而,对于36000km的远程高分辨力可见波段观测,要求望远镜必须具备20m以上口径的主镜。传统的空间相机,如果要有如此大的口径,其总质量将超过1000t,无法发射到GEO上。无支撑薄膜望远镜和大口径衍射望远镜,可以大幅度降低主镜质量面密度,从而降低整个相机系统的总质量,可算是一种极好的技术途径。分步发射与在轨装配,则提供了可供此类观测系统实施从地面转运到GEO的技术手段。基于变换成像原理的傅里叶望远镜,将高分辨力的取得,由增大接收口径转变为加大发射间隔,用大面积回波能量探测加上傅里叶分量重构,取代常见的目标图像直接探测,突破了远程高分辨力观测的致命瓶颈。近完美透镜为突破衍射极限提供了可能性,从而为超分辨力观测开拓出一片科学的新天地。负折射率材料(左手型材料)可制成完美透镜,而光子晶体是负折射率材料的热门选择之一,基于表面等离子激元(SPP)的光子器件则是其另一种选择。 相似文献
872.
In the present analysis of Welcher–Weg (WW) measurements, momentum transfer effects are taken into account. Although the WW apparatus that determines which-way might not include any momentum transfer, there is a momentum transfer to the macroscopic entangled parts of the system (beam-splitter and mirrors in Mach–Zehnder interferometer or macroscopic double-slit wall in 2-slit experiments). We show how a measurement in one location (the WW apparatus) influences the wavefunction at another location (the beam-splitter or 2-slit wall) and fixes momentum at that second place, exactly as that of the EPR effect. 相似文献
873.
I. G. Samusev V. V. Bryukhanov A. M. Ivanov I. S. Labutin B. A. Loginov 《Journal of Applied Spectroscopy》2007,74(2):230-236
We have studied exchange resonance processes of homogeneous triplet-triplet annihilation and heterogeneous triplet-triplet
annihilation for erythrosine and anthracene molecules on an anodized aluminum surface over a broad temperature range. We have
shown that the kinetics of the considered processes are determined by the dimensionality of the molecular clusters on the
porous anodized aluminum surface.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 2, pp. 205–210, March–April, 2007. 相似文献
874.
24 h continuous observation of sodium layer over Wuhan by lidar 总被引:3,自引:0,他引:3
CHENG XueWu GONG ShunSheng LI FaQuan DAI Yang SONG Juan WANG JiaMin & LI FengYan State Key Laboratory of Magnetic Resonance Atomic Molecular Physics Wuhan Institute of Physics Mathematics Chinese Academy of Sciences Wuhan China 《中国科学G辑(英文版)》2007,50(3):287-293
Based on the dual-wavelength lidar we have developed, the 24 h continuous ob- servation has been realized in its sodium channel by using Faraday atomic filter technology and other relevant technologies. This will facilitate the continuous ob- servation of the sodium layer and the relevant upper atmosphere over Wuhan. A result of about 50 h observation indicates that the daytime column density of so- dium layer over Wuhan is slightly increased compared to that during the nighttime, and the characteristics of the sporadic sodium layer occurring during the daytime are compared with that during the nighttime. 相似文献
875.
In this paper, we consider a class of stochastic Nicholson’s blowflies delayed differential equations. Firstly, we obtain the existence and uniqueness of the global positive solution with nonnegative initial conditions. Then the ultimate boundedness in mean of solution is derived under the same condition. Moreover, we estimate the sample Lyapunov exponent of the solution, which is less than a positive constant. In the end, an example with its numerical simulations is carried out to validate the analytical results. 相似文献
876.
Jun Hu Yufei Chang Fan Chen Qingqing Yang Shiyang Shao Lixiang Wang 《Journal of polymer science. Part A, Polymer chemistry》2022,60(12):1855-1863
Two kinds of polystyrene-based through-space charge transfer (TSCT) polymers consisting of spatially-separated acridan donor moieties bearing phenyl or naphthyl substituents and triazine acceptor moieties are designed and synthesized. It is found that TSCT polymers containing phenyl-substituted acridan donors exhibit high-lying singlet (S1) and triplet (T1) states with small singlet-triplet energy splitting (∆EST) of 0.04–0.05 eV, resulting in thermally activated delayed fluorescence (TADF) with reverse intersystem crossing rate constants of 1.1–1.2 × 106 s−1. In contrast, polymers bearing naphthyl-substituted acridan donors, although still having TSCT emission, exhibit no TADF effect because of the large ∆EST of 0.30–0.33 eV induced by low-lying locally excited T1 state of naphthyl donor moiety. Solution-processed organic light-emitting diodes using TSCT polymers containing phenyl-substituted acridan donors reveal sky-blue emission at 483 nm together with maximum external quantum efficiency (EQE) of 11.3%, which is about 30 times that of naphthyl-substituted counterpart with maximum EQE of 0.38%, shedding light on the importance of high triplet energy level of donor moiety on realizing TADF effect and high device efficiency for through-space charge transfer polymer. 相似文献
877.
Dr. Meng Li Prof. Dr. Chuan-Feng Chen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(7):e202103550
A promising strategy of thermally activated delayed fluorescence (TADF) sensitized circularly polarized luminescence (CPL) has been proposed for improving the electroluminescence efficiencies of circularly polarized fluorescent emitters. Compared with chiral TADF emitters which suffer from the dilemma of small ΔEST accompanied by small kr, the TADF-sensitized CPL (TSCP) strategy using TADF molecules as sensitizers and CP-FL molecules as emitters might be the most promising method to construct high-performance circularly polarized organic light-emitting diodes (CP-OLEDs). Consequently, by taking advantage of the theoretically 100 % exciton utilization of TADF sensitizers, especially, by designing CP-FL emitters with high PLQY, narrow FWHM and large glum values, TSCP-type CP-OLEDs with excellent overall performances can be realized. 相似文献
878.
Prof. Hisahiro Sasabe Suguru Araki Shoki Abe Nozomi Ito Kengo Kumada Taito Noda Yoshihito Sukegawa Prof. Daisuke Yokoyama Prof. Junji Kido 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(13):e202104408
The weak stability of a hole-transporter upon approaching the anion state is one of the major bottlenecks for developing long-life organic light-emitting devices (OLEDs). Therefore, in this study, we developed a series of thermally and electrically stable hole-transporters that are end-capped with four dibenzofuran units. These materials exhibit i) high bond dissociation energy (BDE) toward the anion state, ii) a high glass transition temperature (Tg>130 °C), and iii) high triplet energy (ET>2.7 eV), thereby enabling approximately 20 % high external quantum efficiency (EQE) and significantly prolonging the stability of both thermally activated delayed fluorescent (TADF) and phosphorescent OLEDs with an operation lifetime at 50 % (LT50) of 20 000–30 000 h at 1000 cd m−2. In addition, investigating their structure-property relationship revealed that ionization potential (IP), BDE, and Tg are critical prerequisites for the hole-transporter to prolong lifetime in OLEDs. 相似文献
879.
The p-th moment and almost sure stability with general decay rate of the exact solutions of neutral stochastic differential delayed equations with Markov switching are investigated under given conditions. Two examples are provided to support the conclusions. 相似文献
880.
In this paper, synchronization for stochastic hybrid-delayed coupled systems with Lévy noise on a network (SHDCLN) is investigated via aperiodically intermittent control. Here time delays, Markovian switching and Lévy noise are considered on a network simultaneously for the first time. After that, by means of Lyapunov method, graph theory, and some techniques of inequality, some sufficient conditions are derived to guarantee the synchronization for SHDCLN. In addition, the designed range of aperiodically intermittent controller parameters is shown. Meanwhile, the coupling strength and the perturbed intensity of noise have a great impact on the intensity of control. Then, we investigate synchronization for stochastic hybrid delayed Chua's circuits with Lévy noise on a network as a practical application of our theoretical results. Finally, a numerical example is given to illustrate the effectiveness of the theoretical results. 相似文献