全文获取类型
收费全文 | 125779篇 |
免费 | 11491篇 |
国内免费 | 15521篇 |
专业分类
化学 | 76613篇 |
晶体学 | 2390篇 |
力学 | 7612篇 |
综合类 | 1787篇 |
数学 | 16721篇 |
物理学 | 47668篇 |
出版年
2023年 | 924篇 |
2022年 | 2121篇 |
2021年 | 2832篇 |
2020年 | 3184篇 |
2019年 | 3307篇 |
2018年 | 3685篇 |
2017年 | 4062篇 |
2016年 | 4372篇 |
2015年 | 3729篇 |
2014年 | 5073篇 |
2013年 | 7089篇 |
2012年 | 7101篇 |
2011年 | 7817篇 |
2010年 | 6653篇 |
2009年 | 6980篇 |
2008年 | 7318篇 |
2007年 | 6778篇 |
2006年 | 6498篇 |
2005年 | 5720篇 |
2004年 | 4883篇 |
2003年 | 4003篇 |
2002年 | 4099篇 |
2001年 | 4008篇 |
2000年 | 3610篇 |
1999年 | 2524篇 |
1998年 | 1985篇 |
1997年 | 1717篇 |
1996年 | 1638篇 |
1995年 | 1371篇 |
1994年 | 1473篇 |
1993年 | 1428篇 |
1992年 | 1331篇 |
1991年 | 1323篇 |
1990年 | 1329篇 |
1989年 | 1261篇 |
1988年 | 1092篇 |
1987年 | 1064篇 |
1986年 | 1013篇 |
1985年 | 995篇 |
1984年 | 1020篇 |
1983年 | 918篇 |
1982年 | 867篇 |
1981年 | 773篇 |
1979年 | 845篇 |
1978年 | 838篇 |
1977年 | 819篇 |
1976年 | 926篇 |
1975年 | 817篇 |
1974年 | 850篇 |
1973年 | 845篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
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
32.
Komarova E. G. Sedelnikova M. B. Kazantseva E. A. Uvarkin P. V. Sharkeev Yu. P. 《Russian Physics Journal》2020,63(7):1249-1256
Russian Physics Journal - A relationship between the structural-morphological and physical-mechanical properties of macro-porous calcium phosphate (CaP) coatings on the surface of titanium implants... 相似文献
33.
Hongling Yu Heyong Wang Galia Pozina Chunyang Yin Xiao-Ke Liu Feng Gao 《Chemical science》2020,11(41):11338
Metal halide perovskites have demonstrated impressive properties for achieving efficient monochromatic light-emitting diodes. However, the development of white perovskite light-emitting diodes (PeLEDs) remains a big challenge. Here, we demonstrate a single-emissive-layer all-perovskite white PeLED using a mixed halide perovskite film as the emissive layer. The perovskite film consists of separated mixed halide perovskite phases with blue and red emissions, which are beneficial for suppressing halide anion exchange and preventing charge transfer. As a result, the white PeLED shows balanced white light emission with Commission Internationale de L''Eclairage coordinates of (0.33, 0.33). In addition, we find that the achievement of white light emission from mixed halide perovskites strongly depends on effective modulation of the halide salt precursors, especially lead bromide and benzamidine hydrochloride in our case. Our work provides very useful guidelines for realizing single-emissive-layer all-perovskite white PeLEDs based on mixed halide perovskites, which will spur the development of high-performance white PeLEDs.We demonstrated a single-emissive-layer all-perovskite white light-emitting diode based on a mixed halide perovskite film. 相似文献
34.
Complex Study of the Spearhead Superficial Crust from Burial Mound no. 1 near Novosvobodnaya Village
Loboda A. Yu. Kolobylina N. N. Veligzhanin A. A. Zubavitchus Y. V. Tereshchenko E. Yu. Shishlina N. I. Yatsishina E. B. Kashkarov P. K. 《Crystallography Reports》2018,63(2):295-301
A complex study of a spearhead dated back to IV mill. BC from burial mound no. 1 near Novosvobodnaya village (collection of the State Historical Museum) and, in particular, the material of spearhead superficial crust has been performed. The elemental and phase composition of the metal of spearhead and the superficial crust on its surface have been determined by scanning electron microscopy, jointly with energydispersive X-ray microanalysis and X-ray phase analysis. A comparative analysis of the results of studying the spearhead superficial crust and similar crusts on other artifacts from the mounds near Novosvobodnaya village suggest natural origin of the crust on copper?arsenic artifacts.
相似文献35.
36.
Knyazev A. A. Karyakin M. E. Krupin A. S. Galyametdinov Yu. G. 《Russian Journal of General Chemistry》2015,85(12):2806-2812
Russian Journal of General Chemistry - Hybrid liquid crystal systems with different ratios of the components have been prepared on the basis of 5,5′-di(heptadecyl)-2,2′-bipyridine... 相似文献
37.
Jing Zhihong Ling Baoping Yu Yang Qi Wei Zhang Shufang 《Journal of Sol-Gel Science and Technology》2015,73(1):112-117
Journal of Sol-Gel Science and Technology - A novel gas sensing material, La–Y co-doped TiO2 nanoparticles, was synthesized by sol–gel method and applied to detect organic pollutants... 相似文献
38.
39.
40.
中空介孔SiO2由于中空多孔的结构而常用作功能材料的基底.将中空介孔SiO2进行官能团修饰,并应用为荧光传感材料是中空介孔SiO2一个重要的研究领域.本论文采用聚丙烯酸(PAA)为中空模板,聚醚F127为造孔剂,正硅酸乙酯(TEOS)为硅源,氨水为催化剂在乙醇体系中制备了中空介孔SiO2纳米球.系统研究了搅拌速度和聚醚F127引入量对中空介孔SiO2纳米球形貌及比表面积的影响.通过透射电镜、N2-等温吸附脱附曲线等表征说明该合成方法具有很好的普适性,通过调节F127的引入可以实现对比表面积的有效控制.通过氨基化、席夫碱反应进行荧光修饰,进一步研究表明荧光修饰后的中空介孔SiO2纳米球在水溶液中能够实现对Al3+的有效检测,检测限为1.19×10 -7M. 相似文献