全文获取类型
收费全文 | 20186篇 |
免费 | 144篇 |
国内免费 | 17篇 |
专业分类
化学 | 19184篇 |
晶体学 | 22篇 |
力学 | 68篇 |
数学 | 607篇 |
物理学 | 466篇 |
出版年
2021年 | 204篇 |
2019年 | 151篇 |
2016年 | 177篇 |
2015年 | 168篇 |
2013年 | 319篇 |
2012年 | 353篇 |
2011年 | 357篇 |
2010年 | 233篇 |
2009年 | 179篇 |
2008年 | 288篇 |
2007年 | 322篇 |
2006年 | 271篇 |
2005年 | 230篇 |
2004年 | 197篇 |
2003年 | 163篇 |
1987年 | 139篇 |
1985年 | 185篇 |
1984年 | 198篇 |
1980年 | 312篇 |
1979年 | 234篇 |
1978年 | 1039篇 |
1977年 | 797篇 |
1976年 | 224篇 |
1968年 | 208篇 |
1967年 | 174篇 |
1966年 | 221篇 |
1965年 | 255篇 |
1964年 | 228篇 |
1963年 | 175篇 |
1962年 | 347篇 |
1961年 | 169篇 |
1960年 | 220篇 |
1959年 | 208篇 |
1958年 | 206篇 |
1957年 | 152篇 |
1956年 | 236篇 |
1955年 | 226篇 |
1954年 | 164篇 |
1943年 | 162篇 |
1939年 | 163篇 |
1938年 | 174篇 |
1937年 | 231篇 |
1936年 | 214篇 |
1935年 | 231篇 |
1934年 | 184篇 |
1933年 | 250篇 |
1932年 | 136篇 |
1930年 | 216篇 |
1928年 | 154篇 |
1927年 | 153篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
J. Krause und F. Umland 《Fresenius' Journal of Analytical Chemistry》1989,335(7):791-795
Summary This paper presents some applications of cyclic voltammetry at the interface of two immiscible electrolyte solutions by means of an experimental set-up described in a former publication. When using special sample preparation good results are obtained for the determination of iodide and quinine in pharmaceutical products as well as for the determination of quinine in tonic water and dodecylsulfate in a tooth-salt.
Herrn Prof. Dr. Günther Tölg zum 60. Geburtstag gewidmet 相似文献
Herrn Prof. Dr. Günther Tölg zum 60. Geburtstag gewidmet 相似文献
2.
H. Moers H. Klewe-Nebenius G. Pfennig und H. J. Ache 《Fresenius' Journal of Analytical Chemistry》1987,329(2-3):361-366
Summary The adsorption of gaseous molecular iodine on clean silver surfaces proceeds in the first stage by dissociative chemisorption. After the formation of half a monolayer of chemisorbed iodine atoms the formation of silver iodide begins, which forms a very regular overlayer on top of the substrate. Both iodine species can be distinguished due to a difference in chemical shift of the M4N4, 5N4, 5-Auger transitions. After completion of this overlayer further iodine uptake is slowed down significantly. Above an overlayer thickness of about 10 nm a further progress of the reaction cannot be followed anymore due to the limited information depth of XPS. 相似文献
3.
R. Hefelmann P. Mann A. Aignan F. Filsinger und H. Amsel 《Fresenius' Journal of Analytical Chemistry》1902,41(1):66-68
Ohne Zusammenfassung 相似文献
4.
Mariusz Bednarz Peter Reineker Elena Mena-Osteritz Peter Buerle 《Journal of luminescence》2004,110(4):225-231
We theoretically study the size-dependent relation between absorption spectra of thiophene-based oligomers and the corresponding cyclothiophenes. In our approach based on a Frenkel exciton Hamiltonian, we demonstrate that the geometry and selection rules determine the observed relations between the spectra. 相似文献
5.
6.
Elena Larraz Carlos Elvira Julio San Romn 《Journal of polymer science. Part A, Polymer chemistry》2003,41(11):1641-1649
This article explores the synthesis of a novel methacrylic macromonomer with an amphiphilic character derived from poly(ethylene glycol) tert‐octylphenyl ether (MT) and its respective homopolymer. To know their reactivity in radical copolymerization reactions with methyl methacrylate (MMA), a model monomer (MTm) was synthesized to determine the reactivity ratios and compare them with the low molar fractions of copolymers of MT with MMA because they were difficult to isolate. They were rMTm = 0.97 and rMMA = 0.95. The compositional diagrams when representing the weight fraction of MT and MTm in the feed and the copolymer suggested that a clear correlation exists between the experimental points of the model monomer MTm and the macromonomer MT ones, suggesting that the length of the side poly(ethylene oxide) chain does not affect the reactivity of the methacrylic double bond in the prepared monomers for this type of polymerization reaction. The reactivity ratios of the copolymers have a tendency for the formation of random or Bernoullian copolymers. The glass‐transition temperatures (Tg's) of the prepared copolymers were determined by differential scanning calorimetry, deviated from the Fox equation, and discussed on the basis of treatments that consider the influence of the monomeric units along the copolymer chains, determining the Tg of the corresponding alternating dyads. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1641–1649, 2003 相似文献
7.
Marco Andreatta Elena Chierici Gianluca Occhetta 《Central European Journal of Mathematics》2004,2(2):272-293
Let X be a Fano variety of dimension n, pseudoindex i
X
and Picard number ρX. A generalization of a conjecture of Mukai says that ρX(i
X
−1)≤n. We prove that the conjecture holds for a variety X of pseudoindex i
X
≥n+3/3 if X admits an unsplit covering family of rational curves; we also prove that this condition is satisfied if ρX> and either X has a fiber type extremal contraction or has not small extremal contractions. Finally we prove that the conjecture holds
if X has dimension five. 相似文献
8.
J. Bartella K. Kastner K. Röll und K. -H. Schuller 《Fresenius' Journal of Analytical Chemistry》1987,329(2-3):289-291
Summary Besides functional behaviour of coatings their resistivity against corroding attack is a crucial criterion for quality. The application of special corroding and abrading tests yields after short times predictions about stability of the product in practical use. A number of tests have been applied to thin magnetic storage media. Besides tests of function and visual observations with light- and scanning electron microscopes, AES- and XPS-investigations were applied to discuss corrosion resistivity. 相似文献
9.
R. Möller und H. Viefhaus 《Fresenius' Journal of Analytical Chemistry》1987,329(2-3):331
10.
K. Stein und F. Umland 《Fresenius' Journal of Analytical Chemistry》1986,323(2):176-177
Ohne Zusammenfassung
Wir danken dem Fonds der Chemischen Industrie für finanzielle Unterstützung. 相似文献
Trace analysis of lead, cadmium and manganese in honey and sugar
Wir danken dem Fonds der Chemischen Industrie für finanzielle Unterstützung. 相似文献