全文获取类型
收费全文 | 2695篇 |
免费 | 401篇 |
国内免费 | 314篇 |
专业分类
化学 | 1819篇 |
晶体学 | 102篇 |
力学 | 159篇 |
综合类 | 27篇 |
数学 | 13篇 |
物理学 | 1290篇 |
出版年
2024年 | 2篇 |
2023年 | 15篇 |
2022年 | 47篇 |
2021年 | 60篇 |
2020年 | 85篇 |
2019年 | 90篇 |
2018年 | 86篇 |
2017年 | 74篇 |
2016年 | 113篇 |
2015年 | 118篇 |
2014年 | 113篇 |
2013年 | 369篇 |
2012年 | 178篇 |
2011年 | 181篇 |
2010年 | 137篇 |
2009年 | 147篇 |
2008年 | 168篇 |
2007年 | 164篇 |
2006年 | 196篇 |
2005年 | 117篇 |
2004年 | 112篇 |
2003年 | 118篇 |
2002年 | 131篇 |
2001年 | 87篇 |
2000年 | 75篇 |
1999年 | 65篇 |
1998年 | 46篇 |
1997年 | 35篇 |
1996年 | 34篇 |
1995年 | 37篇 |
1994年 | 29篇 |
1993年 | 21篇 |
1992年 | 34篇 |
1991年 | 20篇 |
1990年 | 9篇 |
1989年 | 8篇 |
1988年 | 10篇 |
1987年 | 12篇 |
1986年 | 13篇 |
1985年 | 11篇 |
1984年 | 9篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1981年 | 8篇 |
1980年 | 5篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1973年 | 3篇 |
1972年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有3410条查询结果,搜索用时 15 毫秒
71.
A new method for the spectrofluorimetric determination of indium by formation of a fluorescent 1:1 complex with 1,2,4-trihydroxyanthraquinone is proposed. The complex is formed in a mixed, 60:40 v/v acetone-water medium at pH 3.8 provided by an acetic acid-sodium acetate buffer. The calibration graph is linear between 10 and 600 ng/ml. The effect of potential interferents on the determination was assessed and the proposed method was applied to the determination of indium in synthetic samples. 相似文献
72.
G. Gebhardt 《Isotopes in environmental and health studies》2013,49(10):347-349
Zur Isolierung von Einshlüssen aus hochlegierten Stählen werden die Hauptkomponenten Fe, Ni, Cr und weitere Metalle durch mehrstufig ausgeführte Flüssig-Flüssig-Extraktionen mit verschiedenen Extraktionsmitteln abgetrennt. Die im Eindampfrückstand der wäβrigen Phase nach der Extraktion verbleibenden Einschlüsse können für die meisten Radionuklide ohne nennenswerte Selbstabsorption mit einem Groβflächenzählrohr oder anderen geeignetenZählvorrichtungen ausgemessen werden. 相似文献
73.
Dagmara I. Strumińska-Parulska 《Isotopes in environmental and health studies》2017,53(2):111-115
The idea behind this study was to investigate the most popular magnesium dietary supplements as a potential additional source of 210Pb in the human diet. The paper presents the results of 210Pb activities determined in different magnesium supplements, as well as an estimation of the annual effective radiation doses from 210Pb decay. The results showed that the highest value of 210Pb activity was found in a magnesium supplement of natural origin (dolomite) with a value of 2.97?±?0.18 mBq g–1. The highest annual radiation dose from 210Pb obtained from the magnesium daily recommended value (0.4 g of pure Mg) was calculated for dolomite tablets as 3.71?±?0.02 µSv·year–1. 相似文献
74.
Dwight W. Chasar 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3-4):149-154
Abstract The reaction of 2,6-di-t-butyl-4-methylphenylphosphorodichloridite with α-diketones in the presence of magnesium metal affords modest yields of 1,3,2-dioxaphospholenes. This may be the first evidence for the existence of the monocoordinate aryloxyphosphinidene intermediate, ROP. 相似文献
75.
Bojan Šoptrajanov Gligor Jovanovski Viktor Stefov Igor Kuzmanovski 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4)
Abstract The infrared (IR) and Raman spectra of MgHPO4. 3H2O and of a series of partially deuterated analogues as well as the IR spectra of MnHPO4. 3H2O have been recorded and interpreted. The analysis of the IR spectra in the HOD bending region rules out the possibility of existence of H3OC+ ions in the structure. 相似文献
76.
The analysis of the oxygen-liquid metal interaction is a topic of particular technological interest. A deep knowledge of the kinetics and transport mechanisms involved in the oxidation phenomena is necessary: the effect of oxidation reactions taking place in the gas phase and the evaporation of oxides must be considered.This paper aims to review our works in order to provide a systematic analysis of the oxidation of pure metals and determine the most likely to keeping oxygen-free the surface in a binary alloy.In addition, the upgrading of this theoretical approach, here briefly described, is addressed to give a contribution to a better understanding of the evolution of oxidation phenomena close to the solid-liquid-gas interfaces. 相似文献
77.
78.
79.
《Angewandte Chemie (International ed. in English)》2017,56(40):12064-12084
Magnesium metal is a superior anode which has double the volumetric capacity of lithium metal and has a negative reduction potential of −2.37 V vs. the standard hydrogen electrode. A major benefit of magnesium is the apparent lack of dendrite formation during charging which is one of the crucial concerns of using a lithium metal anode. In this Review, we highlight the foremost research in the development of electrolytes and cathodes and discuss some of the significant challenges which must be overcome in realizing a practical magnesium battery. 相似文献
80.