全文获取类型
收费全文 | 528篇 |
免费 | 23篇 |
国内免费 | 2篇 |
专业分类
化学 | 485篇 |
晶体学 | 2篇 |
力学 | 6篇 |
数学 | 22篇 |
物理学 | 38篇 |
出版年
2024年 | 1篇 |
2023年 | 4篇 |
2022年 | 24篇 |
2021年 | 28篇 |
2020年 | 19篇 |
2019年 | 43篇 |
2018年 | 30篇 |
2017年 | 20篇 |
2016年 | 34篇 |
2015年 | 20篇 |
2014年 | 31篇 |
2013年 | 30篇 |
2012年 | 46篇 |
2011年 | 44篇 |
2010年 | 31篇 |
2009年 | 21篇 |
2008年 | 21篇 |
2007年 | 29篇 |
2006年 | 15篇 |
2005年 | 19篇 |
2004年 | 7篇 |
2003年 | 7篇 |
2002年 | 8篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1977年 | 1篇 |
1968年 | 1篇 |
1965年 | 1篇 |
1961年 | 2篇 |
排序方式: 共有553条查询结果,搜索用时 15 毫秒
41.
Mochalova E. N. Galikhanov M. F. Mikryukova Ya. K. 《Russian Journal of Applied Chemistry》2019,92(11):1492-1498
Russian Journal of Applied Chemistry - Electret properties of polymeric materials based on DER-331 epoxy oligomer and amine curing agents, produced in the course of synthesis of the polymer in a... 相似文献
42.
Skotnikova D. S. Mochalova A. E. Smirnova L. A. 《Russian Journal of Applied Chemistry》2019,92(5):634-638
Russian Journal of Applied Chemistry - Chitosan copolymers with vinyl monomers: 4-N-vinylpyridine, acrylamide, and acrylic acid, were synthesized and these sorption properties were investigated.... 相似文献
43.
Dr. Yulia Y. Enakieva Dr. Anna A. Sinelshchikova Prof. Mikhail S. Grigoriev Prof. Vladimir V. Chernyshev Dr. Konstantin A. Kovalenko Prof. Irina A. Stenina Prof. Andrey B. Yaroslavtsev Prof. Yulia G. Gorbunova Prof. Aslan Y. Tsivadze 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(45):10552-10556
The design of new solid-state proton-conducting materials is a great challenge for chemistry and materials science. Herein, a new anionic porphyrinylphosphonate-based MOF ( IPCE-1Ni ), which involves dimethylammonium (DMA) cations for charge compensation, is reported. As a result of its unique structure, IPCE-1Ni exhibits one of the highest value of the proton conductivity among reported proton-conducting MOF materials based on porphyrins (1.55×10−3 S cm−1 at 75 °C and 80 % relative humidity). 相似文献
44.
Structural Chemistry - Milestones of historical evolution of the Chemistry Department of the Lomonosov Moscow State University, which was formally separated from the physical-mathematical faculty... 相似文献
45.
The application of X-ray emission spectroscopy (XES) has grown substantially with the development of X-ray free-electron lasers, third and fourth generation synchrotron sources, and high-power benchtop sources. By providing the high X-ray flux required for XES, these sources broaden the availability and application of this method of probing electronic structure. As the number of sources increase, so does the demand for X-ray emission detection and sample delivery systems that are cost effective and customizable. Here, we present a detailed fabrication protocol for von Hamos X-ray optics and give details for a 3D-printed spectrometer design. Additionally, we outline an automated, externally triggered liquid sample delivery system that can be used to repeatedly deliver nanoliter droplets onto a plastic substrate for measurement. These systems are both low cost, efficient, and easy to recreate or modify depending on the application. A low cost multiple X-ray analyzer system enables measurement of dilute samples, whereas the sample delivery limits sample loss and reproducibly replaces spent sample with fresh sample in the same position. While both systems can be used in a wide range of applications, the design addresses several challenges associated specifically with time-resolved XES (TRXES). As an example application, we show results from TRXES measurements of photosystem II, a dilute, photoactive protein. 相似文献
46.
Yulia E. Karpeshina 《Arkiv f?r Matematik》2000,38(1):111-137
An asymptotic formula for the density of states of the polyharmonic periodic operator (?δ) l +V inR n ,n≥2,l>1/2 is obtained. Special consideration is given to the case of the Schrödinger equationn=3,l=1,V being a periodic potential, where the second term of the asymptotic is found. 相似文献
47.
Antony O. Bulanov Igor N. Shcherbakov Yulia P. Tupolova Leonid D. Popov Vladimir V. Lukov Victor A. Kogan Pavel A. Belikov 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(12):o618-o620
A novel chelatofore functionalized spiropyran of the 2‐oxaindane series, namely 8‐formyl‐7‐hydroxy‐3′,3′‐dimethylspiro[2H‐chromene‐2,1′(3′H)‐2‐benzofuran], C19H16O4, is reported. In the crystalline state, dimers are formed as a result of the π–π stacking of aromatic groups of the 2H‐chromene part of the molecule and C—H...O interactions. The Cspiro—O bond length in the pyran ring is 1.4558 (10) Å, which is longer than or equal to the bond length in thermo‐ and photochromic 2‐oxaindane spiropyrans synthesized previously, except for the 7,8‐benzo/6‐NO2 derivative, in which this bond length is 1.465 (2) Å. 相似文献
48.
Kirill P. Birin Yulia G. Gorbunova Aslan Yu. Tsivadze 《Magnetic resonance in chemistry : MRC》2010,48(7):505-515
A novel approach for the structural analysis of heteroleptic triple‐decker (porphyrinato)(phthalocyaninato) lanthanides(III) in solutions is developed. The developed approach consists in molecular mechanics (MM+) optimization of the geometry of the complex taking into account the lanthanide‐induced shift (LIS) datasets. LISs of the resonance peaks in 1H NMR spectra of a series of symmetric complexes [An4P]Ln[(15C5)4Pc]Ln[An4P], where An4P2? is 5,10,15,20‐tetrakis(4‐methoxyphenyl)porphyrinato‐dianion, [(15C5)4Pc]2? is 2,3,9,10,16,17,24,25‐tetrakis(15‐crown‐5)phthalocyaninato‐dianion and Ln = La, Ce, Pr, Nd, Sm, Eu, are analyzed. Analysis of LISs showed two sets of protons in the molecule with opposite signs of shift. Two‐nuclei analysis of LISs testifies isostructurality of the whole series of investigated complexes in solution despite contraction of the lanthanide ions. Model‐free separation of contact and dipolar contributions of LISs was performed with one‐nucleus technique and did not show changes in contact and dipolar terms within the investigated series. MM+ optimization of the molecular structure allowed the interpretation of features of LIS for each particular group of protons. Parameterization of MM + ‐optimized model of molecule with values of structure‐dependent dipolar contributions of LIS allows the development of the precise structural model of the triple‐decker complex in solution. This approach allows the determination of the geometry and structure of the sandwich macrocyclic tetrapyrrolic complexes together with conformational analysis of flexible peripheral substituents in solutions. The developed method can be applied with minor modifications for the determination of structural parameters of other types of lanthanides(III) complexes with tetrapyrrolic ligands and also supramolecular systems based on them. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
49.
50.