全文获取类型
收费全文 | 833篇 |
免费 | 22篇 |
国内免费 | 1篇 |
专业分类
化学 | 522篇 |
晶体学 | 9篇 |
力学 | 21篇 |
数学 | 34篇 |
物理学 | 270篇 |
出版年
2021年 | 9篇 |
2020年 | 9篇 |
2019年 | 5篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 17篇 |
2015年 | 10篇 |
2014年 | 14篇 |
2013年 | 33篇 |
2012年 | 28篇 |
2011年 | 37篇 |
2010年 | 23篇 |
2009年 | 15篇 |
2008年 | 32篇 |
2007年 | 41篇 |
2006年 | 26篇 |
2005年 | 40篇 |
2004年 | 46篇 |
2003年 | 18篇 |
2002年 | 23篇 |
2001年 | 19篇 |
2000年 | 52篇 |
1999年 | 9篇 |
1998年 | 8篇 |
1997年 | 7篇 |
1996年 | 6篇 |
1995年 | 15篇 |
1994年 | 19篇 |
1993年 | 15篇 |
1992年 | 16篇 |
1991年 | 22篇 |
1990年 | 5篇 |
1989年 | 9篇 |
1988年 | 8篇 |
1987年 | 11篇 |
1986年 | 10篇 |
1985年 | 16篇 |
1984年 | 11篇 |
1983年 | 13篇 |
1982年 | 12篇 |
1981年 | 5篇 |
1980年 | 9篇 |
1979年 | 9篇 |
1978年 | 16篇 |
1977年 | 7篇 |
1976年 | 17篇 |
1975年 | 15篇 |
1974年 | 12篇 |
1973年 | 5篇 |
1923年 | 4篇 |
排序方式: 共有856条查询结果,搜索用时 62 毫秒
741.
A. Slaoui A. Barhdadi J. C. Muller P. Siffert 《Applied Physics A: Materials Science & Processing》1986,39(3):159-162
It is well established that the pulsed-laser annealing of as-implanted Si introduces electrically active defects. The aim of this paper is to show that these defects can be neutralized by low-energy hydrogen ion implantation. The techniques used for the sample characterization are current-voltage measurements and capacitance transient spectroscopy. 相似文献
742.
V. M. Muller und G. A. Martynov 《Colloid and polymer science》1976,254(8):753
Ohne Zusammenfassung 相似文献
743.
Ash WW Band HR Blume HT Camporesi T Chadwick GB Clearwater SH Coombes RW Delfino MC De Sangro R Fernandez E Ford WT Gettner MW Goderre GP Groom DE Heltsley BK Hurst RB Johnson JR Lau KH Lavine TL Lee HY Leedy RE Marini A Maruyama T Messner RL Moromisato JH Moss LJ Muller F Nelson HN Peruzzi I Piccolo M Prepost R Qi N Read AL Ritson DM Rosenberg LJ Shambroom WD Sleeman JC Smith JG Venuti JP von Goeler E Wald HB Weinstein R Wiser DE Zdarko RW 《Physical review letters》1985,54(23):2477-2480
744.
Ash WW Band HR Bloom ED Bosman M Camporesi T Chadwick GB Delfino MC De Sangro R Ford WT Gettner MW Goderre GP Godfrey GL Groom DE Hurst RB Johnson JR Lau KH Lavine TL Leedy RE Lippi I Maruyama T Messner RL Moromisato JH Moss LJ Muller F Nelson HN Peruzzi I Piccolo M Prepost R Pyrlik J Qi N Read AL Ritson DM Rosenberg LJ Shambroom WD Sleeman JC Smith JG Venuti JP Verdini PG von Goeler E Wald HB Weinstein R Wiser DE Zdarko RW 《Physical review letters》1987,58(7):640-643
745.
Zapalac G Hsueh SY Muller D Tang J Winston R Swallow EC Berge JP Brenner AE Grafström P Jastrzembski E Lach J Marriner J Raja R Smith VJ McCliment E Newsom C Anderson EW Denisov AS Grachev VT Schegelsky VA Seliverstov DM Smirnov NN Terentyev NK Tkatch II Vorobyov AA Cooper PS Razis P Teig LJ 《Physical review letters》1986,57(13):1526-1529
746.
J. P. Guenier P. Simon J. Delcourt M. F. Didierjean C. Lefevre J. Muller 《Chromatographia》1984,18(3):137-144
Summary After a brief review of several methods described in the literature this paper discusses air-sampling on 2,4-dinitrophenylhydrazine-coated silica gel and identification requirements for aldehydes and ketones most commonly found in industrial pollution.Quantitative analysis of formaldehyde and acetaldehyde either by GC or by HPLC techniques is established using a dynamic system producing test atmospheres and compared with the usual colorimetric determinations. 相似文献
747.
We have described an original method allowing us to determine traces of oxygen in organic compounds such as polymers modified through grafting of functions containing oxygen.The method allows us to obtain oxygen contents included between a few hundred ppm and 7 to 8%. It consists in the pyrolysis of the sample, the reduction of oxygen to carbon monoxide and, finally the detection of the latter in an infrared analyzer. 相似文献
748.
Roger L. Snowden Simon M. Linder Bernard L. Muller Karl H. Schulte-Elte 《Helvetica chimica acta》1987,70(7):1858-1878
The transformation of 36 bis(homoallylic) alcohols VII to alkenones IX and X via β-cleavage of their potassium alkoxides VIIa in HMPA has been investigated (cf. Scheme 2). These studies have established an order of β-cleavage for 2-propenyl, 1-methyl-2propenyl, 2-methyl-2-propenyl, 1,1-dimethyl-2propenyl, and benzyl groups in alkoxides 49a – 56a and have allowed a comparison between the β-cleavege reaction and the oxy-Cope rearrangement in alkoxides 74a – 83a . As illustrative syntheti applications, a two-step preparatio of propenyl ketones 15 – 42 from carboxylic esters is described, together with syntheses of ar-turmerone ( 48 ), α-damascone ((E)- 71 ), β-damascone ((E)- 109 ), and β-damascenone ((E)- 111 ). 相似文献
749.
Roger L. Snowden Simon M. Linder Bernard L. Muller Karl H. Schulte-Elte 《Helvetica chimica acta》1987,70(7):1879-1885
Starting from γ- and δ-lactones 1 – 3 , a two-step preparation of 3-hydroxypropyl and 4- hydroxybutyl propenyl ketones 10 – 18 is described, involving as the key step the β-cleavage of the bis(homoallylic) potassium alkoxides 4a – 9a . The novel methodology is illustrated by a short synthesis of (±)-rose oxide( 20 ). 相似文献
750.
The interaction between polyelectrolytes and Acridine Orange (AO) has been investigated in the case of poly(acrylic acid) (PAA), poly(methacrylic acid) (PMA), and a polycondensate between 1,3-benzene disulfonyl chloride and L -lysine (PLL) by visible absorption and fluorescence spectroscopy. The influence of both polymer ionization and polymer/dye ratio (P/D) on the spectral behavior of the bound dye has been studied. The stacking tendency of AO is found lower in the presence of PLL under compact conformation (in an ionization range depending on the nature of the counterion) with correlated enhancement of the green fluorescence of the monomeric species of the bound dye. The disappearance of the green fluorescence and the dimerization of bound AO are directly related to the increased flexibility of polyion chains upon ionization. Some analogy is found between the behavior of bound AO in the presence of very compact PLL chains and that reported for AO in the presence of native DNA, which might be due to specific interactions responsible for a kind of “intercalation” of the monomeric bound dye. 相似文献