全文获取类型
收费全文 | 1555篇 |
免费 | 29篇 |
国内免费 | 17篇 |
专业分类
化学 | 1041篇 |
晶体学 | 11篇 |
力学 | 23篇 |
数学 | 312篇 |
物理学 | 214篇 |
出版年
2023年 | 5篇 |
2022年 | 21篇 |
2021年 | 37篇 |
2020年 | 21篇 |
2019年 | 28篇 |
2018年 | 27篇 |
2017年 | 23篇 |
2016年 | 56篇 |
2015年 | 33篇 |
2014年 | 50篇 |
2013年 | 104篇 |
2012年 | 89篇 |
2011年 | 98篇 |
2010年 | 70篇 |
2009年 | 86篇 |
2008年 | 93篇 |
2007年 | 93篇 |
2006年 | 96篇 |
2005年 | 72篇 |
2004年 | 74篇 |
2003年 | 41篇 |
2002年 | 54篇 |
2001年 | 20篇 |
2000年 | 28篇 |
1999年 | 16篇 |
1998年 | 18篇 |
1997年 | 17篇 |
1996年 | 19篇 |
1995年 | 19篇 |
1994年 | 8篇 |
1993年 | 15篇 |
1992年 | 12篇 |
1991年 | 7篇 |
1990年 | 16篇 |
1989年 | 10篇 |
1988年 | 4篇 |
1987年 | 6篇 |
1986年 | 8篇 |
1985年 | 13篇 |
1984年 | 15篇 |
1983年 | 13篇 |
1982年 | 14篇 |
1981年 | 10篇 |
1980年 | 9篇 |
1979年 | 7篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1976年 | 4篇 |
1973年 | 6篇 |
1966年 | 2篇 |
排序方式: 共有1601条查询结果,搜索用时 31 毫秒
61.
Dr. Anaïs Depaix Agnieszka Mlynarska-Cieslak Dr. Marcin Warminski Dr. Pawel J. Sikorski Prof. Dr. Jacek Jemielity Dr. Joanna Kowalska 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(47):12190-12197
Labeled RNAs are invaluable probes for investigation of RNA function and localization. However, mRNA labeling remains challenging. Here, we developed an improved method for 3′-end labeling of in vitro transcribed RNAs. We synthesized novel adenosine 3′,5′-bisphosphate analogues modified at the N6 or C2 position of adenosine with an azide-containing linker, fluorescent label, or biotin and assessed these constructs as substrates for RNA labeling directly by T4 ligase or via postenzymatic strain-promoted alkyne-azide cycloaddition (SPAAC). All analogues were substrates for T4 RNA ligase. Analogues containing bulky fluorescent labels or biotin showed better overall labeling yields than postenzymatic SPAAC. We successfully labeled uncapped RNAs, NAD-capped RNAs, and 5′-fluorescently labeled m7Gp3Am-capped mRNAs. The obtained highly homogenous dually labeled mRNA was translationally active and enabled fluorescence-based monitoring of decapping. This method will facilitate the use of various functionalized mRNA-based probes. 相似文献
62.
63.
64.
Pawel Uznanski Agnieszka Walkiewicz-Pietrzykowska Krzysztof Jankowski Joanna Zakrzewska Aleksander M. Wrobel Jacek Balcerzak Jacek Tyczkowski 《应用有机金属化学》2020,34(8):e5674
Amorphous silicon oxycarbide (a-SiOC:H) films produced by remote plasma RPCVD from diethoxymethylsilane (DEMS) were characterized in terms of their basic properties related to the coatings deposited using conventional plasma enhanced PECVD method. The effect of substrate temperature (TS) on the growth rate, chemical composition, structure, and properties of resulting a-SiOC:H films is reported. Film growth is an adsorption-controlled process, wherein two mechanisms can be distinguished with a transition at about TS=70°C. Depending on the temperature, films of different nature can be obtained, from polymer-like to highly crosslinked material with C-Si-O network. The chemical structure of a-SiOC:H films was characterized by FTIR, 13C and 29Si solid-state NMR, and X-ray photoelectron spectroscopes. The a-SiOC:H films were also characterized in terms of their density, refractive index, surface morphology, conformality of coverage, hardness, adhesion to a substrate, and friction coefficient. The films were found to be morphologically homogeneous materials exhibiting good conformality of coverage and small surface roughness. Their refractive index exhibits anomalous effect revealing a minimum value at TS=125°C. Due to their exceptional physical properties a-SiOC:H films produced by RPCVD from DEMS precursor seems to be useful as potential dielectric materials or coatings for various encapsulation applications. 相似文献
65.
66.
67.
68.
69.
Wladyslaw Reimschüssel Halina Abramczyk Jacek Michalak 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3-4):201-211
Abstract 2-Chloro-5,5-dimethyl-2-oxo-1,3,2-dioxaphosphorinane has been studied in CCl4, CHCl3 and CD3CN solutions by IR and Raman line shape analysis. Equilibrium process of dimerization and ring conversion in CCl4 solutions have been considered. On the contrary to the commonly expected dominance of the conformer with the equatorial oriented P[dbnd]O bond for 2-halo-2-oxo-1,3,2-dioxaphosphorinanes, it was found that for the 2-chloro derivative both conformers are nearly equally distributed. It has been shown that the interactions induced absorption is an important mechanism of relaxation in the studied compound and this mechanism gives significant contribution to the total IR band broadening, while the interaction induced light scattering is negligible. The obtained results show that the molecular dynamics method can be useful in studying cyclic compounds in solutions. 相似文献
70.
Jacek E. Nycz 《Phosphorus, sulfur, and silicon and the related elements》2013,188(10):2605-2612
The present study shows new aspects of the synthesis of polyhalogenoarylphosphanes. The sterically hindered anions Ph(R)P-Y? (1a–c, Y = O, lone pair; R = Ph, But) have been used to show the complexity of the reaction between phosphorus nucleophiles and hexahalogenobenzenes or 9-bromofluorene (E3). The Ph(But)P-O? (1a) anion reacts with hexachlorobenzene (E1), hexafluorobenzene (E2), or E3 to give Ph(R)P(O)X (4a–c, X = F, Cl, Br) with the release of the corresponding carbanion as a nucleofuge, followed by side reactions. In contrast, the lithium phosphides Ph(R)PLi (1b,c) react with hexahalogenobenzenes to give the corresponding diphosphanes 5a,b as the main product and traces of P-arylated products, i.e., Ph(R)P-C6X5 (10a,b, X = Cl, F). Unexpectedly, Ph(But)PLi (1b) reacts with an excess of 9-bromofluorene to give only halogenophosphane Ph(But)P-X. 相似文献