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排序方式: 共有850条查询结果,搜索用时 15 毫秒
1.
Numerical Algorithms - Recently, low-rank regularization has achieved great success in tensor completion. However, only considering the global low-rankness is not sufficient, especially for a low... 相似文献
2.
双边配给问题描述了现实生活中一类带有二部图结构的稀缺资源配置问题, 例如, 在自然灾害期间救援物资的配给; 电力和天然气等自然资源按需分配; 高校引进人才调配等。本文通过求解线性规划, 并从联盟边际贡献的角度出发定义了双边配给问题的一个Shapley解。之后, 通过合作对策模型和解的公理化方法说明新解的合理性。首先, 建立双边配给问题的合作对策模型, 论证了新解与双边配给合作对策的Shapley值一致; 其次, 证明了Shapley解是唯一满足优先一致性的有效配给方案。最后, 将Shapley解应用于博物馆通票问题的研究, 探讨了博物馆合作制定通票后所得单票和通票收益的分配方式。 相似文献
3.
基于空间机构的运动特性,考虑空间颤振环境的影响,采用粗粒化分子动力学研究MoS2/Ag薄膜的碰撞滑动接触摩擦性能,建立颤振环境碰撞滑动接触摩擦的粗粒化分子动力学模型,对比了纯Ag和MoS2/Ag薄膜的摩擦性能,研究了初始碰撞速度、滑动速度以及空间温度对碰撞滑动接触摩擦过程的影响. 结果表明:与纯Ag相比,MoS2/Ag薄膜表现出更优异的摩擦性能;压头碰撞速度对动能有一定的贡献,初始碰撞速度的增加会增大压头压入基体的深度,使得平均摩擦力增大;滑动速度的增加会加剧原子间的相互剪切摩擦,使平均摩擦力增加;MoS2/Ag薄膜在100~500 K温度范围内表现出良好的摩擦性能,当空间温度为600 K时,其摩擦性能降低,并伴随着MoS2膜的破裂. 相似文献
4.
Liang-Qing Zhang Shu-Gui Yang Jing-Han Zhang Ke-Peng Zhong Zhong-Guo Zhao Yan-Hui Chen Jun Lei Qiu-Yu Zhang Zhong-Ming Li 《高分子科学》2022,40(3):290-298
Achieving low friction and wear of poly(phenylene sulfide)(PPS) without using fillers or blending is a challenging task, but one of considerable practical importance. Here we describe how neat PPS with high tribological performance is achieved by manipulating processing parameters(pressure, flow and temperature). The key to achieving high tribological performance is comparatively high molecular chain orientation, realized in neat PPS, at high shear rates and low pressure. The friction coefficient and wear rate are as low as ~0.3 and~10-6 mm3·N-1·m-1, respectively, which break the record for neat PPS. These values are even better than those for PPS-based blends and comparable to PPS composites. Further studies show, for the first time, that wear rate decreases exponentially with increasing molecular chain orientation, prompting us to revise the classical Archard's law by including the effect of molecular chain orientation. These findings open the possibility of using neat PPS in highly demanding tribological applications. 相似文献
5.
利用声波的多普勒频移可以对窄带运动声源进行单传感器无源测速,其性能很大程度上取决于能否精确地估计出声波的瞬时频率.Wigner-Ville分布虽然时频分辨率高,但存在交叉项干扰,很少被直接用于瞬时频率估计。对此,提出了抵消Wigner-Ville分布交叉项的单传感器窄带声源无源测速方法。利用交叉项与声源速度的关系构造一个抵消项,引入到Wigner-Ville分布中,通过对声源速度估计值进行迭代更新,使抵消项与交叉项相位相反,从而约掉交叉项。经实测噪声数据验证,对一辆以6.07 m/s匀速运动的卡车(信噪比约为29 dB)测速误差为0.1 m/s,运行时间为4.6 s,对一架以28.90 m/s匀速运动的直升机(信噪比约为16 dB)测速误差为0.46 m/s,运行时间为1.2 s,均优于匹配Wigner变换和多普勒线性调频小波变换测速方法. 相似文献
6.
Meiling Chen Chenxi Peng Yaoquan Su Xue Chen Prof. Yuezhou Zhang Prof. Yu Wang Prof. Juanjuan Peng Dr. Qiang Sun Prof. Xiaowang Liu Prof. Wei Huang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(47):21174-21181
The ability to incorporate functional metal ions (Mn+) into metal–organic coordination complexes adds remarkable flexibility in the synthesis of multifunctional organic–inorganic hybrid materials with tailorable electronic, optical, and magnetic properties. We report the cation-exchanged synthesis of a diverse range of hollow Mn+-phytate (PA) micropolyhedra via the use of hollow Co2+-PA polyhedral networks as templates at room temperature. The attributes of the incoming Mn+, namely Lewis acidity and ionic radius, control the exchange of the parent Co2+ ions and the degree of morphological deformation of the resulting hollow micropolyhedra. New functions can be obtained for both completely and partially exchanged products, as supported by the observation of Ln3+ (Ln3+=Tb3+, Eu3+, and Sm3+) luminescence from as-prepared hollow Ln3+-PA micropolyhedra after surface modification with dipicolinic acid as an antenna. Moreover, Fe3+- and Mn2+-PA polyhedral complexes were employed as magnetic contrast agents. 相似文献
7.
Dr. Kai Dang Dr. Wenjuan Zhang Dr. Shanfeng Jiang Dr. Xiao Lin Prof. Dr. Airong Qian 《ChemistryOpen》2020,9(3):285-300
Many proteins in living organisms are glycosylated. As their glycan patterns exhibit protein-, cell-, and tissue-specific heterogeneity, changes in the glycosylation levels could serve as useful indicators of various pathological and physiological states. Thus, the identification of glycoprotein biomarkers from specific changes in the glycan profiles of glycoproteins is a trending field. Lectin microarrays provide a new glycan analysis platform, which enables rapid and sensitive analysis of complex glycans without requiring the release of glycans from the protein. Recent developments in lectin microarray technology enable high-throughput analysis of glycans in complex biological samples. In this review, we will discuss the basic concepts and recent progress in lectin microarray technology, the application of lectin microarrays in biomarker discovery, and the challenges and future development of this technology. Given the tremendous technical advancements that have been made, lectin microarrays will become an indispensable tool for the discovery of glycoprotein biomarkers. 相似文献
8.
Adaptive shock control bumps can exploit the on-design drag-reducing potential of 2D bumps, while mitigating their off-design performance deterioration through geometric modifications. In this study, experiments and simulations have been employed to investigate the wave-drag reducing potential of (actuated and unconstrained) 2D adaptive shock control bumps over a wide range of shock positions. Experiments were carried out in the Imperial College supersonic wind tunnel, modelling the adaptive bump as a flexible surface placed beneath a Mach 1.4 shock wave. 2D RANS CFD simulations of the flow in a parallel channel with a solid bump complement experiments. Wave drag was demonstrated to be proportional to the ratio of inlet to exit stagnation pressure in a blow-down wind tunnel for a given shock position. The shock exhibits a hysteretic behaviour when travelling in the wind tunnel working section, governed by the wave drag reducing potential of the bump. The actuated adaptive bump tested reduces wave drag over a wider operational envelope than solid bumps as experiments revealed the presence of three preferred structural configurations, which lead to a significantly enlarged hysteresis region. Finally, tests on unconstrained bumps were shown to increase wave drag, both on- and off-design, due to the unfavourable bump shapes that result from (only) passive actuation, suggesting that some constraints are required to achieve desirable surface deformations. 相似文献
9.
利用射频磁控溅射法在(LaAlO3)0.3(SrAl0.5Ta0.5O3)0.7 (001)单晶基底上生长了镧掺杂BaSnO3外延薄膜. 通过Hall效应和热电势测量证实了镧掺杂BaSnO3薄膜具有n型简并半导体特征, 并且基于载流子浓度和Seebeck系数计算出电子的有效质量为0.31m0 (m0为自由电子质量). 镧掺杂BaSnO3薄膜在可见波段具有良好的透明性(透过率大于73%). 基于介电模型对薄膜的透过率曲线进行拟合, 从拟合结果中不仅得到了薄膜的厚度为781.2 nm, 能带宽度为3.43 eV、 带尾宽度为0.27 eV和复光学介电常数随波长的变化规律, 而且也强力地支持了基于电学参数计算电子有效质量的正确性. 相似文献
10.