全文获取类型
收费全文 | 5337篇 |
免费 | 879篇 |
国内免费 | 605篇 |
专业分类
化学 | 3970篇 |
晶体学 | 52篇 |
力学 | 304篇 |
综合类 | 47篇 |
数学 | 523篇 |
物理学 | 1925篇 |
出版年
2024年 | 17篇 |
2023年 | 148篇 |
2022年 | 181篇 |
2021年 | 227篇 |
2020年 | 272篇 |
2019年 | 212篇 |
2018年 | 176篇 |
2017年 | 177篇 |
2016年 | 251篇 |
2015年 | 228篇 |
2014年 | 316篇 |
2013年 | 358篇 |
2012年 | 486篇 |
2011年 | 461篇 |
2010年 | 323篇 |
2009年 | 321篇 |
2008年 | 340篇 |
2007年 | 327篇 |
2006年 | 312篇 |
2005年 | 219篇 |
2004年 | 159篇 |
2003年 | 133篇 |
2002年 | 137篇 |
2001年 | 99篇 |
2000年 | 99篇 |
1999年 | 104篇 |
1998年 | 94篇 |
1997年 | 91篇 |
1996年 | 69篇 |
1995年 | 93篇 |
1994年 | 80篇 |
1993年 | 51篇 |
1992年 | 63篇 |
1991年 | 48篇 |
1990年 | 41篇 |
1989年 | 29篇 |
1988年 | 17篇 |
1987年 | 15篇 |
1986年 | 10篇 |
1985年 | 11篇 |
1984年 | 7篇 |
1983年 | 4篇 |
1982年 | 7篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1978年 | 2篇 |
1928年 | 2篇 |
排序方式: 共有6821条查询结果,搜索用时 31 毫秒
1.
Karakuş Erman Erdemir Eda Suna Garen Liv Lokman Gunduz Simay Can Şevval Arzu 《Journal of fluorescence》2021,31(6):1617-1625
Journal of Fluorescence - We have constructed a novel fluorescein-based fluorescent chemosensor, FL-In, functionalised with an indole moiety and capable of sensing by both the optical... 相似文献
2.
Nonlinear Dynamics - The classical Kuramoto model serves as a useful tool for studying synchronization transitions in coupled oscillators that is limited to the sinusoidal and pairwise... 相似文献
3.
Dr. Yong-Sheng Wei Dr. Liming Sun Miao Wang Dr. Jinhua Hong Dr. Lianli Zou Hongwen Liu Dr. Yu Wang Dr. Mei Zhang Dr. Zheng Liu Prof. Yinwei Li Prof. Satoshi Horike Prof. Kazu Suenaga Prof. Qiang Xu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(37):16147-16156
Understanding the thermal aggregation behavior of metal atoms is important for the synthesis of supported metal clusters. Here, derived from a metal–organic framework encapsulating a trinuclear FeIII2FeII complex (denoted as Fe3) within the channels, a well-defined nitrogen-doped carbon layer is fabricated as an ideal support for stabilizing the generated iron nanoclusters. Atomic replacement of FeII by other metal(II) ions (e.g., ZnII/CoII) via synthesizing isostructural trinuclear-complex precursors (Fe2Zn/Fe2Co), namely the “heteroatom modulator approach”, is inhibiting the aggregation of Fe atoms toward nanoclusters with formation of a stable iron dimer in an optimal metal–nitrogen moiety, clearly identified by direct transmission electron microscopy and X-ray absorption fine structure analysis. The supported iron dimer, serving as cooperative metal–metal site, acts as efficient oxygen evolution catalyst. Our findings offer an atomic insight to guide the future design of ultrasmall metal clusters bearing outstanding catalytic capabilities. 相似文献
4.
We present the fabrication of core-shell-satellite Au@SiO2-Pt nanostructures and demonstrate that LSPR excitation of the core Au nanoparticle can induce plasmon coupling effect to initiate photocatalytic hydrogen generation from decomposition of formic acid. Further studies suggest that the plasmon coupling effect induces a strong local electric field between the Au core and Pt nanoparticles on the SiO2 shell, which enables creation of hot electrons on the non-plasmonic-active Pt nanoparticles to participate hydrogen evolution reaction on the Pt surface. In addition, small SiO2 shell thickness is required in order to obtain a strong plamon coupling effect and achieve efficient photocatalytic activities for hydrogen generation. 相似文献
5.
6.
Jigneshkumar P. Patel Zou Guo Xiang Shaw Ling Hsu Andrew B. Schoch Sena Ada Carleen Dean Matsumoto 《Journal of Polymer Science.Polymer Physics》2015,53(21):1519-1526
A uniform dispersion of reactants is necessary to achieve a complete reaction involving multicomponents. In this study, we have examined the role of plasticizer in the reaction of two seemingly unlikely reactants: a highly crystalline hexamethylenetetramine (HMTA) and a strongly hydrogen bonded phenol formaldehyde resin. By combining information from NMR, infrared spectroscopy and differential scanning calorimetry, we were able to determine the role of specific intermolecular interactions necessary for the plasticizer to dissolve the highly crystalline HMTA and to plasticize the phenol formaldehyde resin in this crosslinking reaction. The presence of the plasticizer increased the segmental mobility, disrupted the hydrogen bonded matrix, and freed the hydroxyl units, which further increased the solubility of the HMTA. Both the endothermic and exothermic transitions are accounted for in the calorimetric data obtained. For the first time, it is possible to obtain the effective molar ratio of each component needed to complete the crosslinking reaction efficiently. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 1519–1526 相似文献
7.
8.
9.
10.
This paper reports that the m-plane GaN layer is grown on (200)-plane LiAlO2 substrate by metal-organic chemical wpour deposition (MOCVD) method. Tetragonal-shaped crystallites appear at the smooth surface. Raman measurement illuminates the compressive stress in the layer which is released with increasing the layer's thickness. The high transmittance (80%), sharp band edge and excitonic absorption peak show that the GaN layer has good optical quality. The donor acceptor pair emission peak located at -3.41 eV with full-width at half maximum of 120 meV and no yellow peaks in the photoluminescence spectra partially show that no Li incorporated into GaN layer from the LiAlO2 substrate. 相似文献