全文获取类型
收费全文 | 988篇 |
免费 | 27篇 |
国内免费 | 2篇 |
专业分类
化学 | 732篇 |
晶体学 | 8篇 |
力学 | 2篇 |
数学 | 22篇 |
物理学 | 253篇 |
出版年
2023年 | 11篇 |
2022年 | 9篇 |
2021年 | 14篇 |
2020年 | 11篇 |
2019年 | 22篇 |
2018年 | 8篇 |
2016年 | 17篇 |
2015年 | 13篇 |
2014年 | 20篇 |
2013年 | 39篇 |
2012年 | 40篇 |
2011年 | 45篇 |
2010年 | 34篇 |
2009年 | 30篇 |
2008年 | 51篇 |
2007年 | 41篇 |
2006年 | 48篇 |
2005年 | 41篇 |
2004年 | 39篇 |
2003年 | 45篇 |
2002年 | 25篇 |
2001年 | 41篇 |
2000年 | 22篇 |
1999年 | 15篇 |
1998年 | 7篇 |
1997年 | 17篇 |
1996年 | 9篇 |
1995年 | 13篇 |
1994年 | 13篇 |
1993年 | 12篇 |
1992年 | 13篇 |
1991年 | 13篇 |
1990年 | 18篇 |
1989年 | 15篇 |
1988年 | 10篇 |
1987年 | 15篇 |
1986年 | 8篇 |
1985年 | 18篇 |
1984年 | 14篇 |
1983年 | 8篇 |
1982年 | 13篇 |
1981年 | 14篇 |
1980年 | 8篇 |
1979年 | 6篇 |
1978年 | 11篇 |
1977年 | 10篇 |
1976年 | 7篇 |
1975年 | 6篇 |
1974年 | 10篇 |
1973年 | 6篇 |
排序方式: 共有1017条查询结果,搜索用时 15 毫秒
31.
Cinabro D Henderson S Kinoshita K Liu T Saulnier M Wilson R Yamamoto H Sadoff AJ Ammar R Ball S Baringer P Coppage D Copty N Davis R Hancock N Kelly M Kwak N Lam H Kubota Y Lattery M Nelson JK Patton S Perticone D Poling R Savinov V Schrenk S Wang R Alam MS Kim IJ Nemati B O'Neill JJ Romero V Severini H Sun CR Zoeller MM Crawford G Fulton R Fujino D Gan KK Kagan H Kass R Lee J Malchow R Morrow F Skovpen Y Sung M White C Whitmore J Wilson P Butler F Fu X Kalbfleisch G Lambrecht M Ross WR 《Physical review letters》1993,70(24):3700-3704
32.
33.
Haas P Hempstead M Jensen T Kagan H Kass R Behrends S Gentile T Guida JM Guida JA Morrow F Poling R Rosenfeld C Thorndike EH Tipton P Besson D Green J Namjoshi R Sannes F Skubic P Stone R Bortoletto D Chen A Goldberg M Horwitz N Jawahery A Lubrano P Moneti GC Trahern CG van Hecke H Csorna SE Garren L Mestayer MD Panvini RS Word GB Yi X Alam MS Bean A Ferguson T Avery P Bebek C Berkelman K Blucher E Cassel DG Copie T DeSalvo R DeWire JW Ehrlich R Galik RS Gilchriese MG Gittelman B Gray SW 《Physical review letters》1985,55(12):1248-1251
34.
35.
36.
The biosynthetic origins of amphidinoide B (1) were investigated on the basis of 13C-NMR data of 13C-enriched samples obtained by feeding experiments with [1-(13)C], [2-(13)C], and [1,2-(13)C2] sodium acetates in cultures of a dinoflagellate Amphidinium sp. These incorporation patterns suggested that 1 was generated from three successive polyketide chains, an isolated C1 unit from C-2 of acetates, six branched C1 units from C-2 of acetates, and an "m-m" and an "m-m-m" unit derived only from C-2 of acetates. The labeling patterns of amphidinolide B (1) were different from those of amphidinolide H (2), a 26-membered macrolide closely related to 1. 相似文献
37.
The use of an amperometric biosensor for the salicylate determination in blood serum is described. The biosensor is based on salicylate hydroxylase (EC 1.14.13.1) electropolymerized onto a glassy carbon-working electrode with polypyrrole and glutaraldehyde, to improve the biosensor lifetime. The hexacyanoferrate (II) was also incorporated to work as a redox mediator to minimize possible interferences. The salicylate is enzymatically converted to catechol, which is monitored amperometrically by its electrooxidation at+0.170 V versus SCE (saturated calomel electrode). Salicylate determination was carried out maintaining the ratio between beta-NADH and salicylate at 4:1 (30 degrees C). The amperometric response of the biosensor was linearly proportional to the salicylate concentration between 2.3x10(-6) and 1.4x10(-5) mol l(-1), in 0.1 mol l(-1) phosphate buffer (pH 7.8), containing 0.1 mol l(-1) KCl and 5.0x10(-4) mol l(-1) Na(2)H(2)EDTA, as supporting electrolyte. The recovery studies, in the presence of several interfering compounds, showed recoveries between 96.4 and 104.8%. The useful lifetime of the biosensor in the concentration range evaluated was at least 40 days, in continuous use. Blood serum samples analyzed by this biosensor showed a good correlation compared to the spectrophotometric method (Trinder) used as reference, presenting relative deviations lower than 7.0%. 相似文献
38.
39.
Hitoshi Kubota Yukitaka Murata Yoshitaka Ogiwara 《Journal of polymer science. Part A, Polymer chemistry》1973,11(2):485-492
The effects of swelling of the sample and polymerization solvents were studied for photo-induced graft copolymerization of vinyl monomers on cellulose. The graft copolymerization of methyl methacrylate (MMA) was activated by swelling of the sample or organic solvent-water solutions within a certain range of their concentrations. Though each organic solvent gave a maximum in per cent grafting and the number of grafts at about 25 vol-% concentration, the initiation reaction scarcely took place at 100% concentration; thus, the solvent itself is considered to have a negative effect. The solvents used in the experiments were all hydrophilic, such as methanol, acetone, and dioxane. The average molecular weight of the grafted PMMA differed in each solvent, indicating a different characteristic effect of solvent on the growing grafted polymer radicals. The presence of ferric ion as a sensitizer stimulated further the contributions of the sample swelling and the organic solvents to the copolymerization reaction. A similar effect was observed for styrene as for MMA, but not for acrylic acid and methacrylic acid. 相似文献
40.
Fukuji Higashi Koichi Kubota Misuzu Sekizuka Morio Higashi 《Journal of polymer science. Part A, Polymer chemistry》1981,19(11):2681-2687
Polyaryl esters of moderate molecular weights were prepared by the direct polycondensation reaction of hydroxybenzoic acids and its derivatives with hexachlorocyclotriphosphatriazene (also known as phosphonitrilic chloride trimer, PNC) as a condensing agent in pyridine. Copolymerization of p-hydroxybenzoic acid with several hydroxybenzic acid derivatives was carried out to improve the processability of the polymer of p-hydroxybenzoic acid, which yields fusible and soluble copolymers of high inherent viscosities. Polymer solubility and thermal behavior were examined. 相似文献