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991.
992.
基于SSH(Su-Schrieffer-Heeger)模型,采用静态及动力学自洽算法模拟了有机高分子链内激子在光激发及外电场作用下的形成与解离过程。结果表明,受光激发后,有机高分子链内激子的生成与解离密切依赖于施加外电场的时机,当外电场与光激发同时发生时,激子能否生成完全取决于电场强度的大小;而当外电场在光激发后的一段时间(通常为皮秒量级)之后被引入,则在有机高分子链内能够形成稳定的激子,且该激子只有在强外电场(超过1MV/cm)的作用下,才会发生解离,临界场强量级与实验结果相符合。 相似文献
993.
Opinions of individuals in real social networks are arguably strongly influenced by external determinants, such as the opinions of those perceived to have the highest levels of authority. In order to model this, we have extended an existing model of consensus formation in an adaptive network by the introduction of a parameter representing each agent’s level of ‘authority’, based on their opinion relative to the overall opinion distribution. We found that introducing this model, along with a randomly varying opinion convergence factor, significantly impacts the final state of converged opinions and the number of interactions required to reach that state. We also determined the relationship between initial and final network topologies for this model, and whether the final topology is robust to node removals. Our results indicate firstly that the process of consensus formation with a model of authority consistently transforms the network from an arbitrary initial topology to one with distinct measurements in mean shortest path, clustering coefficient, and degree distribution. Secondly, we found that subsequent to the consensus formation process, the mean shortest path and clustering coefficient are less affected by both random and targeted node disconnection. Speculation on the relevance of these results to real world applications is provided. 相似文献
994.
采用基于密度泛函理论的第一性原理方法,对正交碘化铟(InI)晶体可能存在的6种本征点缺陷(碘空位、铟空位、碘占铟位、铟占碘位、碘间隙、铟间隙)结构进行优化. 通过缺陷形成能的计算,得出各缺陷在生长过程中形成的难易程度;通过态密度的计算,分析出各种缺陷能级位置及其对载流子传输的影响. 结果表明:最主要的低能缺陷铟间隙会引入复合中心和深空穴陷阱,前者降低少数载流子的寿命,后者俘获价带的空穴而降低空穴的迁移率-寿命积. 计算结果为实验中提高InI 晶体载流子的迁移率-寿命积提供理论指导,对获得性能优异的InI核辐射探测材料有重要帮助.
关键词:
碘化铟
形成能
缺陷能级
深空穴陷阱 相似文献
995.
Electroconvection is a classical example of pattern-forming phenomena in liquid crystals, typically observed in nematics with negative dielectric and positive conductivity anisotropies. This article focuses on how electroconvection in the homeotropic geometry differs from that in planar alignment. The influence of an additional magnetic field on the pattern characteristics and on secondary instabilities (the normal roll–abnormal roll transition) is discussed. The homeotropic alignment offers unique possibilities also for studying defect motion. Basic characteristics of some patterns of large wavelength are presented and compared with those of the classical Carr–Helfrich structures. Finally, electroconvection in substances with negative conductivity anisotropy is addressed. 相似文献
996.
Debashish Chowdhury Katsuhiro Nishinari Andreas Schadschneider 《Phase Transitions》2013,86(5-7):601-624
Flocks of birds and schools of fish are familiar examples of spatial patterns formed by living organisms. In contrast to the patterns on the skins of, say, zebras and giraffes, the patterns of our interest are transient although different patterns change over different timescales. The aesthetic beauty of these patterns has attracted the attention of poets and philosophers for centuries. Scientists from various disciplines, however, are in search of common underlying principles that give rise to the transient patterns in colonies of organisms. Such patterns are observed not only in colonies of organisms as simple as single-cell bacteria, but also in social insects like ants and termites. They are also observed in colonies of vertebrates as complex as birds and fish, and in human societies. In recent years, physicists have utilized the framework of statistical physics to understand these patterns. In this article, we present an overview emphasizing the common trends that rely on theoretical modeling of these systems using the so-called agent-based Lagrangian approach. 相似文献
997.
假定Fitting子群F(G)或广义Fitting子群F*(G)的某些子群在G中SQ-补来研究包含超可解群的饱和群系s,这里G∈s.一些已知结果被推广. 相似文献
998.
999.
1000.
Prof. Dr. Hiromichi Fujioka Kenzo Yahata Tomohito Hamada Ozora Kubo Takashi Okitsu Yoshinari Sawama Takuya Ohnaka Dr. Tomohiro Maegawa Prof. Dr. Yasuyuki Kita 《化学:亚洲杂志》2012,7(2):367-373
Mild substitution reactions of acetals with carbon nucleophiles via the pyridinium‐type salts generated by the treatment of acetals with TESOTf‐2,4,6‐collidine or 2,2′‐bipyridyl have been developed. Various carbon nucleophiles, such as organocuprates, silyl enol ethers, enamines, etc., reacted with the pyridinium‐type salts to give the corresponding substituted products in good yields. The reactions proceeded under very mild conditions (non‐acidic conditions) and thus acid‐sensitive functional groups can be tolerated during the reaction. In addition, only an acetal can form the pyridinium‐type salt and react with nucleophiles in the presence of a ketal. This unusual selectivity is in contrast to general methods conducted under acidic conditions. 相似文献