全文获取类型
收费全文 | 24796篇 |
免费 | 1320篇 |
国内免费 | 1550篇 |
专业分类
化学 | 15322篇 |
晶体学 | 189篇 |
力学 | 1709篇 |
综合类 | 136篇 |
数学 | 3431篇 |
物理学 | 6879篇 |
出版年
2021年 | 312篇 |
2020年 | 431篇 |
2019年 | 566篇 |
2018年 | 556篇 |
2017年 | 543篇 |
2016年 | 761篇 |
2015年 | 533篇 |
2014年 | 728篇 |
2013年 | 1016篇 |
2012年 | 1041篇 |
2011年 | 1038篇 |
2010年 | 1029篇 |
2009年 | 929篇 |
2008年 | 1029篇 |
2007年 | 987篇 |
2006年 | 844篇 |
2005年 | 766篇 |
2004年 | 719篇 |
2003年 | 770篇 |
2002年 | 935篇 |
2001年 | 883篇 |
2000年 | 587篇 |
1999年 | 423篇 |
1998年 | 330篇 |
1997年 | 277篇 |
1996年 | 262篇 |
1995年 | 243篇 |
1993年 | 247篇 |
1992年 | 259篇 |
1991年 | 277篇 |
1990年 | 281篇 |
1989年 | 267篇 |
1985年 | 277篇 |
1984年 | 286篇 |
1983年 | 261篇 |
1982年 | 274篇 |
1980年 | 254篇 |
1979年 | 299篇 |
1978年 | 329篇 |
1977年 | 320篇 |
1976年 | 403篇 |
1975年 | 358篇 |
1974年 | 388篇 |
1973年 | 395篇 |
1972年 | 368篇 |
1971年 | 331篇 |
1970年 | 314篇 |
1969年 | 298篇 |
1968年 | 253篇 |
1967年 | 250篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Physics of the Solid State - The phase transitions in the two-dimensional diluted Potts model with the number of spin states q = 3 are studied by computer simulation method. The systems... 相似文献
2.
Zhi Sun Mengfan Zhao Lihua Zuo Shengnan Zhou Feng Fan Qingquan Jia Lianping Xue Hanbing Li Jian Kang Xiaojian Zhang 《Journal of separation science》2022,45(2):518-528
Juglandis Mandshuricae Cortex is the bark of Juglans mandshurica Maxim., which has been used as a folk medicine plant in China and India. In this study, an ultra-high performance liquid chromatography–quadrupole/orbitrap high-resolution mass spectrometry method was developed to clarify and quantify the chemical profiling of Juglandis Mandshuricae Cortex rapidly. A total of 113 compounds were characterized. Among them, seven flavonoids were simultaneously quantified in 15 min, including myricetin, myricetrin, taxifolin, kaempferol, quercetin, quercitrin, and naringenin. The method was validated for accuracy, precision, and the limits of detection and quantification. All calibration curves showed a good linear relationship (r > 0.9990) within test ranges. The intra- and inter-day relative standard deviations were less than 2.16%. Accuracy validation showed that the recovery was between 95.6 and 101.3% with relative standard deviation values below 2.85%. The validated method was successfully applied to determine the contents of seven flavones in Juglandis Mandshuricae Cortex from seven sources and the contents of these places were calculated respectively. This method provides a theoretical basis for further developing the medicinal value of Juglandis Mandshuricae Cortex. 相似文献
3.
Eliovich Ya. A. Blagov A. E. Kocharyan V. R. Gogolev A. S. Targonsky A. V. Movsisyan A. E. Korzhov V. A. Mkrtchyan A. R. Kovalchuk M. V. 《JETP Letters》2022,115(3):148-152
JETP Letters - Features of the simultaneous action of longitudinal and transverse ultrasonic vibrations in the quartz crystal on the parameters of reflected X-rays are studied. It is shown that... 相似文献
4.
Zhao Tianqi Luo Tianzi Fang Bo Shi Lijiang Jin Yongxing Zhou Pengwei Yao Dong Li Chenxia Jing Xufeng Hong Zhi 《Journal of Russian Laser Research》2021,42(5):586-597
Journal of Russian Laser Research - The zero-refractive-index metamaterials have excellent electromagnetic properties, which provide new ideas and methods to realize the control of electromagnetic... 相似文献
5.
Shklover V. Ya. Kazanskii P. R. Artemov N. A. Maryasev I. G. 《Crystallography Reports》2021,66(4):663-672
Crystallography Reports - The development of fundamental and applied geology requires an ever-increasing amount of data on the structures and properties of rocks at different scales. Of particular... 相似文献
6.
Journal of Experimental and Theoretical Physics - In this paper, we consider Hamiltonian structures of hydrodynamic type and some of their generalizations. In particular, we discuss the questions... 相似文献
7.
Volk T. R. Bodnarchuk Ya. V. Gainutdinov R. V. Kokhanchik L. S. Shandarov S. M. 《JETP Letters》2021,113(12):769-779
JETP Letters - Studies of ferroelectric nano- and microdomain structures formed in LiNbO3-based optical waveguides are reviewed. Nanodomain structures of a given configuration have been written in... 相似文献
8.
Nonlinear Dynamics - The hybrid neural model provides a computationally effective and biophysics-based neuron behavior model, which maintains its simplicity by incorporating the dynamics... 相似文献
9.
Mathematical Notes - Let $$\mathbb N$$ denote the set of all nonnegative integers, and let $$A\subseteq\mathbb N$$ . Let $$h,n\in\mathbb N$$ , $$h\ge 2$$ and $$r_h(A,n)=\#\{(a_1,\dots,a_h)\in... 相似文献
10.
Cytochrome P450 119 Compounds I Formed by Chemical Oxidation and Photooxidation Are the Same Species
Dr. Zhi Su Dr. John H. Horner Prof. Dr. Martin Newcomb 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(61):14015-14020
Compound I from cytochrome P450 119 prepared by the photooxidation method involving peroxynitrite oxidation of the resting enzyme to Compound II followed by photooxidation to Compound I was compared to Compound I generated by m-chloroperoxybenzoic acid (MCPBA) oxidation of the resting enzyme. The two methods gave the same UV/Visible spectra, the same products from oxidations of lauric acid and palmitic acid and their (ω-2,ω-2,ω-3,ω-3)-tetradeuterated analogues, and the same kinetics for oxidations of lauric acid and caprylic acid. The experimental identities between the transients produced by the two methods leave no doubt that the same Compound I species is formed by the two methods. 相似文献