全文获取类型
收费全文 | 299518篇 |
免费 | 4201篇 |
国内免费 | 1063篇 |
专业分类
化学 | 133881篇 |
晶体学 | 4236篇 |
力学 | 11603篇 |
综合类 | 2篇 |
数学 | 27776篇 |
物理学 | 84496篇 |
无线电 | 42788篇 |
出版年
2021年 | 2433篇 |
2020年 | 2628篇 |
2019年 | 2898篇 |
2018年 | 3501篇 |
2017年 | 3413篇 |
2016年 | 5278篇 |
2015年 | 3338篇 |
2014年 | 5423篇 |
2013年 | 12584篇 |
2012年 | 10134篇 |
2011年 | 12252篇 |
2010年 | 8759篇 |
2009年 | 9129篇 |
2008年 | 11978篇 |
2007年 | 12275篇 |
2006年 | 11611篇 |
2005年 | 10704篇 |
2004年 | 9895篇 |
2003年 | 8702篇 |
2002年 | 8554篇 |
2001年 | 9279篇 |
2000年 | 7474篇 |
1999年 | 6018篇 |
1998年 | 5194篇 |
1997年 | 5075篇 |
1996年 | 4789篇 |
1995年 | 4396篇 |
1994年 | 4275篇 |
1993年 | 4355篇 |
1992年 | 4358篇 |
1991年 | 4468篇 |
1990年 | 4142篇 |
1989年 | 3962篇 |
1988年 | 3899篇 |
1987年 | 3456篇 |
1986年 | 3287篇 |
1985年 | 4332篇 |
1984年 | 4509篇 |
1983年 | 3648篇 |
1982年 | 3787篇 |
1981年 | 3701篇 |
1980年 | 3562篇 |
1979年 | 3591篇 |
1978年 | 3704篇 |
1977年 | 3645篇 |
1976年 | 3723篇 |
1975年 | 3421篇 |
1974年 | 3395篇 |
1973年 | 3475篇 |
1972年 | 2415篇 |
排序方式: 共有10000条查询结果,搜索用时 920 毫秒
81.
Bi Dongxue Sverbil Pavel P. Voinov Yury P. Wu Mengyuan 《Journal of Russian Laser Research》2021,42(6):671-676
Journal of Russian Laser Research - We discuss the use of high-pressure high-temperature (HPHT) diamonds for the determination of trace amounts of various Raman active substances. The amount of the... 相似文献
82.
Kazantsev Yu. N. Kraftmakher G. A. Mal’tsev V. P. 《Journal of Communications Technology and Electronics》2019,64(6):550-554
Journal of Communications Technology and Electronics - Approximate formulas for calculating the coefficient of reflection from an artificial magnetic conductor (AMC) based on a capacitive lattice... 相似文献
83.
Kuzmenkova P. S. Gromushkin D. M. Shulzhenko I. A. Tretyakova T. D. 《Physics of Atomic Nuclei》2021,84(9):1588-1592
Physics of Atomic Nuclei - The paper presents a comparison of three neutrons identifying methods in scintillators based on ZnS with 6Li and 10B: charge integration method, pulse gradient analysis,... 相似文献
84.
Mathematical Notes - 相似文献
85.
Isaeva A. I. Maikov E. Gibizova V. V. Petrova G. P. 《Journal of Applied Spectroscopy》2021,88(4):789-793
Journal of Applied Spectroscopy - Aqueous solutions of human hemoglobin have been studied by the multi-angle static light scattering method. The tendency of sickle-shaped erythrocytes to aggregate... 相似文献
86.
Crystallography Reports - Nd1 – yEuyF3 – y crystals (y is the molar fraction of EuF2; 0 ≤ y ≤ 0.15) with a tysonite (LaF3) structure have... 相似文献
87.
Wang Hay Kan Chenxi Wei Dongchang Chen Tao Bo Bao‐Tian Wang Yan Zhang Yangchao Tian Jun‐Sik Lee Yijin Liu Guoying Chen 《Advanced functional materials》2019,29(17)
Lithium‐rich disordered rock‐salt oxides have attracted great interest owing to their promising performance as Li‐ion battery cathodes. While experimental and theoretical efforts are critical in advancing this class of materials, a fundamental understanding of key property changes upon Li extraction is largely missing. In the present study, single‐crystal synthesis of a new disordered rock‐salt cathode material, Li1.3Ta0.3Mn0.4O2 (LTMO), and its use as a model compound to investigate Li concentration–driven evolution of local cationic ordering, charge compensation, and chemical distribution are reported. Through the combined use of 2D and 3D X‐ray nanotomography, it is shown that Li removal accompanied by oxygen oxidation is correlated with the development of morphological defects such as particle cracking. Chemical heterogeneity, quantified by subparticle level distribution of Mn valence state, is minimal during Mn redox, which drastically increases upon the formation of cracks during oxygen redox. Density functional theory and bond valence sum mismatch calculations reveal the presence of local short‐range ordering in the pristine oxide, which gradually disappears along with the extraction of Li. The study suggests that with cycling the transformation into true cation–disordered state can be expected, which likely impacts the voltage profile and obtainable energy density of the oxide cathodes. 相似文献
88.
Avanesyan V. T. Provotorov P. S. Stozharov V. M. Sychev M. M. Eruzin A. A. 《Optics and Spectroscopy》2021,129(11):1196-1199
Optics and Spectroscopy - The optical absorption spectra of zinc oxide (ZnO) thin films formed by reactive cathode sputtering are studied. The observed absorption of light in the region of photon... 相似文献
89.
E. V. Shadrina O. N. Malinkina T. G. Khonina A. B. Shipovskaya V. I. Fomina E. Yu. Larchenko N. A. Popova I. G. Zyryanova L. P. Larionov 《Russian Chemical Bulletin》2015,64(7):1633-1639
The biomimetic sol—gel synthesis of silicon—chitosan-containing glycerohydrogels was carried out using silicon tetraglycerolate as a precursor. It was found that chitosan accelerates gel formation in weakly acidic media. In more acidic media, the kinetics of the process changes according to the curve with a maximum, which can be attributed to different mechanisms of silanol condensation before and after the isoelectric point. The investigated silicon—chitosan-containing glycerohydrogels exhibit antibacterial, anti-inflammatory, and wound healing activity. The synthesized hybrid glycerohydrogels are promising materials for biomedical applications. 相似文献
90.
Dorovskikh S. I. Stabnikov P. А. Zelenina L. N. Sysoev S. V. Morozova N. B. 《Russian Journal of General Chemistry》2021,91(10):1977-1983
Russian Journal of General Chemistry - Thermogravimetry, differential scanning calorimetry, and flow methods were used to investigate thermal properties of a series of cobalt(II)... 相似文献