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141.
张德良  严海星 《光学学报》1998,18(10):366-1371
在采用冻结湍流假设和几何光学近似的条件下,得到了经自适应光学系统校正后的剩余波前相位扰动的结构函数,进而根据剩余相位结构函数与系统Strehl比的关系,求出自适应光学系统的补偿效果受系统的时空传递函数,大气湍流,光波传播路径上的横向风,观察目标的旋转角速度以及系统时间延迟影响情况的解析表达式。  相似文献   
142.
Super Narrow Bandpass Filter Using Fractal Cantor Structures   总被引:1,自引:0,他引:1  
In this paper, we present a new photonic crystal structure, which is composed of fractal Cantor multilayer with a defect embedded in its middle. Optical transmission matrix method is used to calculating the transmittance and reflectance. Compared with general Cantor multilayer, we find the new structure has wider stopband and shows a super narrow band in the middle of wider stopband. It can be served as a super narrow bandpass filter. The pass band obtained can be less than 0.6nm near the infrared 1530 nm. The optical transmission is the center wavelength is higher than 99 %. This means a very low insert loss. It is more superior to other kind narrow band filters. This kind of photonic crystal super narrow band optical filter may find applications in super dense wavelength division multiplexing for optical communications and precise optical measurement.  相似文献   
143.
In the millimetre and submillimetre wavebands the attenuation of signals due to atmospheric water vapour absorption is not negligible. A theory of scintillation is presented which links the phase variation to the observed fluctuations in signal intensity. Analysis of observations shows that, at sea level, scintillation is present under normal observing conditions.  相似文献   
144.
The direct hydroxylation of benzene using molecular oxygen by atmospheric pulse DC corona discharge was investigated. The conversion of benzene increased with the increase of oxygen content and input voltage but the selectivity of phenol decreased due to the formation of polymerized products. The reactivity was also influenced by the kind and content of background inert gas. By using argon as background gas, we could get 2.2% of phenol yield at 60°C and 1 atm with energy consumption of 50 W. The strategy of reductive oxidation, which added hydrogen to the reactant, was not favorable to the phenol formation in this reaction system. The polymerized product showed the oligomeric character and the analysis of its chemical structure with FT–IR was presented.  相似文献   
145.
A general four-layer structure linear theory for predicting the effects of arbitrarilydistributed roughness change on the variations of wind speed and shear stress in the surfacelayer of3D and2D atmospheres was presented.The results derived by the theory wereagreeable to the previous ones.  相似文献   
146.
湍流大气中图像传输的信息量   总被引:1,自引:1,他引:0  
张逸新 《光学学报》1994,14(4):30-435
分别从系统像的信息量和信息自由度的角度分析了大气湍流对相干和不相干照明光学系统成像质量和分辨率的影响。理论上,处于一定大气湍流条件下的相干照明系统存在着超出经典衍射极限的超分辨率。  相似文献   
147.
Thin polycrystalline films of SnO2 and antimony doped SnO2 have been prepared by simple economic electroless deposition technique. The transmittance in the visible range and the reflectance in the i.r. range for SnO2 films are ~80% and ~70%, respectively, with resistivity ~10?2 Ω cm. On the other hand, antimony doped SnO2 films have transmittance in the visible range and reflectance in the i.r. range, as good as ~86% and ~83%, respectively, with resistivity as low as ~10?3Ω cm. By vacuum annealing, the resistivity of both types of films has been brought down as low as ~10?3 and ~10?4 Ω cm, respectively.  相似文献   
148.
New and improved strategies are eagerly sought for the rapid identification of microorganisms, particularly in mixtures. Mass spectrometry remains a powerful tool for this purpose. Small acid-soluble proteins (SASPs), which are relatively abundant in Bacillus spores, represent potential biomarkers for species characterization. Despite sharing extensive sequence homology, these proteins differ sufficiently in sequence for discrimination between species. This work focuses on the differences in sequence between SASPs from various Bacillus species. Compilation of SASP sequences from protein database searches, followed by in silico trypsin digestion and analysis of the resulting fragments, identified several species-specific peptides that could be targeted for analysis using mass spectrometry. This strategy was tested and found to be successful in the characterization of Bacillus spores both from individual species and in mixtures. Analysis was performed using an ion trap mass spectrometer with an atmospheric pressure MALDI source. This instrumentation offers the advantage of increased speed of analysis and accurate precursor ion selection for tandem mass spectrometric analysis compared with vacuum matrix-assisted laser desorption/ionization and time-of-flight instruments. The identification and targeting of species-specific peptides using this type of instrumentation offers a rapid, efficient strategy for the identification of Bacillus spores and can potentially be applied to different microorganisms.  相似文献   
149.
用传输矩阵法计算了两端对称缺陷复合光子晶体结构的光传输特性。计算结果表明:两端对称缺陷复合光子晶体[D(AB)mD]2结构中的禁带出现两个完全共振透射峰。通过控制入射光强来微调光子晶体材料的介电常数,使得完全共振透射峰移动,且介电常数变化越大,共振透射峰偏移越大,从而形成高效率的双通道光开关。当光子晶体为[D(AB)mD]N结构时,每个完全共振透射峰都分裂为N-1条,这样可通过调节N同时实现所需要通道数目的高效多通道光开关和多通道滤波器。  相似文献   
150.
大气压微波等离子体炬的仿真设计与实验   总被引:2,自引:2,他引:0       下载免费PDF全文
设计了一个低成本、高稳定性的基于BJ22矩形波导的微波等离子体炬源。整个系统由1~10 kW主频2.45 GHz的磁控管微波功率源、环形器、调谐器和微波反应腔体组成。通过特殊设计的调谐装置,在气体喷嘴处产生高幅值的电场强度,使工作气体电离形成大气压开放式微波等离子体炬。对影响电场强度的几个关键因素进行了仿真,得出各个参数对场强的影响规律;根据仿真参数设计了微波反应腔体,该系统可以在大气压下激发和维持开放的稳定氩气、氦气、氮气和空气等离子体炬。对等离子体炬的基本特性和基本参数进行了研究,验证了设计参数的正确性,讨论了其可扩展性及潜在的工业应用。  相似文献   
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