全文获取类型
收费全文 | 2763篇 |
免费 | 128篇 |
国内免费 | 10篇 |
专业分类
化学 | 2315篇 |
晶体学 | 12篇 |
力学 | 25篇 |
数学 | 286篇 |
物理学 | 263篇 |
出版年
2023年 | 21篇 |
2022年 | 36篇 |
2021年 | 34篇 |
2020年 | 51篇 |
2019年 | 39篇 |
2018年 | 28篇 |
2017年 | 22篇 |
2016年 | 101篇 |
2015年 | 103篇 |
2014年 | 88篇 |
2013年 | 140篇 |
2012年 | 207篇 |
2011年 | 234篇 |
2010年 | 140篇 |
2009年 | 85篇 |
2008年 | 184篇 |
2007年 | 169篇 |
2006年 | 157篇 |
2005年 | 165篇 |
2004年 | 162篇 |
2003年 | 127篇 |
2002年 | 114篇 |
2001年 | 68篇 |
2000年 | 37篇 |
1999年 | 35篇 |
1998年 | 27篇 |
1997年 | 32篇 |
1996年 | 29篇 |
1995年 | 27篇 |
1994年 | 17篇 |
1993年 | 18篇 |
1992年 | 21篇 |
1991年 | 12篇 |
1990年 | 14篇 |
1989年 | 9篇 |
1988年 | 23篇 |
1987年 | 15篇 |
1986年 | 7篇 |
1985年 | 13篇 |
1984年 | 18篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1981年 | 13篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1978年 | 13篇 |
1977年 | 4篇 |
1976年 | 4篇 |
1975年 | 3篇 |
1969年 | 5篇 |
排序方式: 共有2901条查询结果,搜索用时 15 毫秒
61.
62.
63.
John J. Goodell Christine M. Egnatuk Stephen W. Padgett Corey C. Keith Todd A. Bredeweg Norris K. Harward Bryan B. Bandong Kevin E. Roberts Alice C. Mignerey 《Journal of Radioanalytical and Nuclear Chemistry》2018,316(2):475-483
Theoretical activation calculations for Fe, Ni, and stainless steel foils were compared against irradiated foil measurements from a critical assembly. Calculated/experiment values spanning 0.62–1.31 showed that the restricted approach used here is insufficient for experiment planning, with the collapsed cross-section being the primary source of error. The effect of decay time on gamma-ray spectroscopy measurement reliability was investigated using a Monte Carlo HPGe detector model. Simulations showed no correlation with decay time, absent interferences. Specific interferences for Fe-59 (Ni) and Co-60 (stainless steel) activation product ratios suggested optimal measurement windows having respective decay times of 9–11 days and 4–7 days. 相似文献
64.
Tatiana Cañeque Sebastian Müller Anne Lafon Fabien Sindikubwabo Antoine Versini Lou Saier Manon Barutaut Christine Gaillet Raphaël Rodriguez 《Comptes Rendus Chimie》2018,21(7):704-708
Cancer stem cells (CSCs) have been shown to be refractory to conventional therapeutic agents, can promote metastasis, and have been linked to cancer relapse. Salinomycin can selectively kill CSCs. We have shown that salinomycin derivatives accumulate in lysosomes and sequester iron in this organelle. As a result, accumulation of iron leads to the production of reactive oxygen species and lysosomal membrane permeabilization, which in turn promotes cell death by ferroptosis. These findings have revealed the prevalence of iron homeostasis in CSCs and paved the way toward the development of next-generation therapeutics. 相似文献
65.
C. Michael Hamilton Maurita Hung Gang Chen Zafar Qureshi John R. Thompson Bingyun Sun Christine E. Bear Robert N. Young 《Tetrahedron》2018,74(38):5528-5538
Cystic Fibrosis (CF) is a genetic disorder caused by loss-of-function mutations to the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR) protein. Ivacaftor (1) was the first therapeutic approved for the treatment of CF that is able to restore gating activity to certain CFTR variants although the mechanism of action is poorly understood. Herein we describe the synthesis of a photoaffinity labelling (PAL) probe (2) based on the structure of ivacaftor incorporating a photoreactive diazirine moiety for use in labelling studies designed to identify the binding site for ivacaftor on mutant CFTR. The PAL probe 2 retained potentiation activity, with a potency similar to 1, using a Fluorescent Imaging Plate Reader (FLIPR®) assay measuring ion conductance potentiation of wild type (Wt)-CFTR. Photolabelling experiments with human serum albumin (HSA) as a model protein have shown that probe 2 can label HSA in a manner consistent with observed and predicted binding. 相似文献
66.
Access to the Bis‐benzene Cobalt(I) Sandwich Cation and its Derivatives: Synthons for a “Naked” Cobalt(I) Source? 下载免费PDF全文
Stefan C. Meier Albina Holz Jan Kulenkampff Alexei Schmidt Dr. Daniel Kratzert Dr. Daniel Himmel Dominik Schmitz Dr. Ernst‐Wilhelm Scheidt Prof. Dr. Wolfgang Scherer Dr. Christine Bülow Martin Timm Dr. Rebecka Lindblad Dr. Scott T. Akin Dr. Vicente Zamudio‐Bayer Prof. Dr. Bernd von Issendorff Prof. Dr. Michael A. Duncan Prof. Dr. J. Tobias Lau Prof. Dr. Ingo Krossing 《Angewandte Chemie (International ed. in English)》2018,57(30):9310-9314
The synthesis and structural characterization of the hitherto unknown parent Co(bz)2+ (bz=benzene) complex and several of its derivatives are described. Their synthesis starts either from a CoCO5+ salt, or directly from Co2(CO)8 and a Ag+ salt. Stability and solubility of these complexes was achieved by using the weakly coordinating anions (WCAs) [Al(ORF)4]? and [F{Al(ORF)3}2]? {RF=C(CF3)3} and the solvent ortho‐difluorobenzene (o‐DFB). The magnetic properties of Co(bz)2+ were measured and compared in the condensed and gas phases. The weakly bound Co(o‐dfb)2+ salts are of particular interest for the preparation of further CoI salts, for example, the structurally characterized low‐coordinate 12 valence electron Co(PtBu3)2+ and Co(NHC)2+ salts. 相似文献
67.
Christine Mousty Arielle Lepellec Serge Cosnier Andres Novoa Robert S. Marks 《Electrochemistry communications》2001,3(12):727-732
We describe herein, the creation of an organic phase enzyme electrode (OPEE) via avidin–biotin interactions built over an electrogenerated polymer. Multilayered polyphenol oxidase (PPO) assemblies were transferred into an organic solvent (chloroform) for the catechol detection at −0.2 V. In conjunction with an alginate gel, as a hydrophilic additive, the biosensor performance was widely enhanced. The effects of biotinylated polypyrrole film and alginate gel on the diffusion process through the biosensor coating are studied by rotating disk electrode experiments carried out in chloroform with hydroquinone as electroactive permeant. 相似文献
68.
69.
The adsorption of Mo from dilute aqueous solutions (10(-3) to 3x10(-2) M) is effected on three samples of titania, two are anatase and the third is P25, which is composed of rutile and anatase. The adsorption isotherms at 298, 318, and 338 K are analyzed using a Langmuir linear equation. The isotherms on P25 showed a distinct inflection point that is reproduced by two linear portions, indicating different adsorption regimes. This adsorption behavior is explained as follows: with low amount adsorbed the adsorption is initiated by protonation of the basic hydroxyls on which the negatively charged MoO(4)(2-')s are adsorbed, and this is accompanied by an increase in the pH of the impregnating solution. At higher adsorption the coordinatively unsaturated Ti(4+) sites participate in the process, leading to a decline in the initial increase in pH. In the case of the two anatase samples the low surface area resulted in poor distribution of adsorption sites; consequently, the distinction between the two modes of adsorption was not entirely clear. The higher adsorption site density in the case of anatase is accompanied by a lower surface coverage, θ, than that for P25. The heat of adsorption, Q, on the three titania samples showed a linear increase with θ, which is represented by the regression equation: -Q=95.77θ-4.25 (R(2)=0.993). Copyright 2001 Academic Press. 相似文献
70.
Eichhorn C Scherer OJ Sögding T Wolmershäuser G 《Angewandte Chemie (International ed. in English)》2001,40(15):2859-2861