全文获取类型
收费全文 | 1456篇 |
免费 | 56篇 |
国内免费 | 18篇 |
专业分类
化学 | 1021篇 |
晶体学 | 13篇 |
力学 | 63篇 |
数学 | 162篇 |
物理学 | 271篇 |
出版年
2024年 | 5篇 |
2023年 | 21篇 |
2022年 | 20篇 |
2021年 | 61篇 |
2020年 | 66篇 |
2019年 | 68篇 |
2018年 | 76篇 |
2017年 | 39篇 |
2016年 | 62篇 |
2015年 | 50篇 |
2014年 | 83篇 |
2013年 | 166篇 |
2012年 | 129篇 |
2011年 | 104篇 |
2010年 | 75篇 |
2009年 | 61篇 |
2008年 | 51篇 |
2007年 | 44篇 |
2006年 | 55篇 |
2005年 | 27篇 |
2004年 | 32篇 |
2003年 | 17篇 |
2002年 | 17篇 |
2001年 | 19篇 |
2000年 | 23篇 |
1999年 | 12篇 |
1998年 | 6篇 |
1997年 | 9篇 |
1996年 | 5篇 |
1995年 | 10篇 |
1994年 | 12篇 |
1992年 | 4篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1987年 | 9篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1984年 | 5篇 |
1983年 | 7篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1979年 | 6篇 |
1978年 | 8篇 |
1977年 | 3篇 |
1976年 | 6篇 |
1974年 | 7篇 |
1966年 | 2篇 |
1960年 | 5篇 |
1959年 | 3篇 |
1958年 | 2篇 |
排序方式: 共有1530条查询结果,搜索用时 564 毫秒
101.
Sajid Muhammad Munir Shad Naveed Akthar Javed Yasir Khan Sadaf Bashir Zhang Zhengjun Amin Nasir 《Research on Chemical Intermediates》2020,46(2):1201-1215
Research on Chemical Intermediates - We prepared unique BiVO4/reduce graphene oxide (BiVO4/rGO) nanocomposite with enhanced photocatalytic ability by hydrothermal method applying... 相似文献
102.
Sodium bromide efficiently catalyses the regioselective cleavage of oxiranes with chlorotrimethylsilane to the corresponding O-silylated chlorohydrins in excellent yields. 相似文献
103.
Amin Esfahani 《Applied Mathematics Letters》2011,24(2):204-209
In this work, we study the perturbed nonlinear Klein–Gordon equation. We shall use the sech-ansätze method to derive the solitary wave solutions of this equation. 相似文献
104.
105.
We calculate the strong coupling constants of light pseudoscalar mesons with heavy baryons within the light cone QCD sum rules method. It is shown that sextet–sextet, sextet–antitriplet and antitriplet–antitriplet transitions are described by one universal invariant function for each class. A comparison of our results on the coupling constants with the predictions existing in literature is also presented. 相似文献
106.
The isomorphic substitution of boron into ZSM‐5 zeolite under static hydrothermal condition was investigated. Evaluation of hydrothermal synthesis of BZSM‐5 was performed by treating the synthesis mixture by different aging processes, namely, ultrasonic, static, stirring, and microwave‐assisted aging prior to the conventional hydrothermal treatment. The synthetic processes with different techniques of aging prior to the onset of conventional hydrothermal crystallization were compared with a process without any prior aging. The obtained results showed that the ultrasonic and microwave assisted aging shortened the crystallization time and altered the crystal size and the morphology of the obtained products. The characteristics of the synthesized products were obtained by FT‐IR spectroscopic, XRD and SEM techniques. 相似文献
107.
H. Hora G.H. Miley M. Ghoranneviss B. Malekynia N. Azizi 《Optics Communications》2009,282(20):4124-4126
Anomalous interaction of terawatt-picosecond laser pulses allows side-on ignition of solid state density fusion fuel with the unexpected possibility of igniting uncompressed hydrogen–boron p-11B. Suppression of relativistic self-focusing by using very clean laser pulses with an extremely high contrast ratio is essential to achieve ignition thresholds only ten times more difficult than fusion of deuterium–tritium (DT). This opens the possibility for laser driven fusion energy without neutrons and less radioactivity than from burning coal. The complex nonlinear optical properties involved are elaborated. 相似文献
108.
A liquid chromatographic procedure was developed for quantitative determination of histidine (His), histidinol (HDL), histamine (HTM), urocanic acid (URA), imidazolepyruvic acid (ImPA), imidazoleacetic acid (ImAA), and imidazolelactic acid (ImLA) in rumen fluid. The method is based on direct injection analysis by UV absorbance detection at 220 nm. The separation was performed under 2 different chromatographic conditions on a LiChrospher 100 NH2 column. In the first chromatographic system, the mobile phase used for isocratic elution was 67 mM potassium phosphate buffer (monobasic and dibasic) pH 6.45-90% acetonitrile in water (21 + 79); in the second system, an acetonitrile gradient in 63 mM potassium phosphate buffer (monobasic) pH 3.0, obtained by addition of 60 mM phosphoric acid, was used. Analyses of both systems were completed within 32 and 25 min, respectively. The limits of detection of these compounds were (microM): His, 2.8; HDL, 3.7; HTM, 4.0; URA, 0.75; ImPA, 4.7; ImAA, 1.2; and ImLA, 1.3. Recovery of these compounds added to rumen fluid was 97.4-103.0% within a 1-day study and 95.4-99.0% on different day studies. Detectable levels of His were found in the deproteinized rumen fluid of goats, with average concentrations of 16.10, 10.43, 11.14, and 13.62 microM in the rumen fluid collected before the morning feeding and 2, 4, and 6 h after feeding, respectively. HDL, HTM, URA, ImPA, ImAA, and ImLA were not detected in the rumen fluid before and after feeding. Trp, Phe, and Tyr were also identified in the rumen fluid, with average concentrations of 8.25, 29.04, and 12.6 microM, respectively, before the morning feeding. 相似文献
109.
Sandra Feisel Joachim von zur Gathen M. Amin Shokrollahi. 《Mathematics of Computation》1999,68(225):271-290
Gauss periods have been used successfully as a tool for constructing normal bases in finite fields. Starting from a primitive th root of unity, one obtains under certain conditions a normal basis for over , where is a prime and for some integer . We generalize this construction by allowing arbitrary integers with , and find in many cases smaller values of than is possible with the previously known approach.
110.
M. S. Manhas S. G. Amin S. D. Sharma B. Dayal Ajay K. Bose 《Journal of heterocyclic chemistry》1979,16(2):371-376
A series of heterocyclic analogs of diarylethylene and triarylethylene were synthesized as potential anti-implantation agents. Tested in rats as oral, post-coital antifertilily agents, a few of our compounds showed some activity. 相似文献