全文获取类型
收费全文 | 27771篇 |
免费 | 948篇 |
国内免费 | 154篇 |
专业分类
化学 | 18599篇 |
晶体学 | 161篇 |
力学 | 666篇 |
综合类 | 3篇 |
数学 | 4825篇 |
物理学 | 4619篇 |
出版年
2023年 | 174篇 |
2022年 | 160篇 |
2021年 | 541篇 |
2020年 | 510篇 |
2019年 | 462篇 |
2018年 | 838篇 |
2017年 | 588篇 |
2016年 | 808篇 |
2015年 | 716篇 |
2014年 | 769篇 |
2013年 | 1521篇 |
2012年 | 1723篇 |
2011年 | 1860篇 |
2010年 | 1165篇 |
2009年 | 986篇 |
2008年 | 1677篇 |
2007年 | 1651篇 |
2006年 | 1566篇 |
2005年 | 1494篇 |
2004年 | 1219篇 |
2003年 | 1090篇 |
2002年 | 905篇 |
2001年 | 469篇 |
2000年 | 500篇 |
1999年 | 321篇 |
1998年 | 297篇 |
1997年 | 285篇 |
1996年 | 372篇 |
1995年 | 223篇 |
1994年 | 235篇 |
1993年 | 224篇 |
1992年 | 204篇 |
1991年 | 156篇 |
1990年 | 163篇 |
1989年 | 139篇 |
1988年 | 151篇 |
1987年 | 118篇 |
1986年 | 128篇 |
1985年 | 193篇 |
1984年 | 204篇 |
1983年 | 130篇 |
1982年 | 168篇 |
1981年 | 150篇 |
1980年 | 124篇 |
1979年 | 106篇 |
1978年 | 140篇 |
1977年 | 117篇 |
1976年 | 126篇 |
1975年 | 102篇 |
1973年 | 80篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Peralta Cecilia Mariana Acosta Gimena Henestrosa Cecilia Gil Raúl Andrés Fernández Liliana Patricia 《Journal of Analytical Chemistry》2022,77(3):308-317
Journal of Analytical Chemistry - The present development involved a flow injection strategy using a mini-column of multiwalled carbon nanotubes and fluorescent detection (λex of 283 nm,... 相似文献
2.
Ana-Maria Udrea Andra Dinache Jean-Marie Pags Ruxandra Angela Pirvulescu 《Molecules (Basel, Switzerland)》2021,26(8)
Multidrug resistance of bacteria is a worrying concern in the therapeutic field and an alternative method to combat it is designing new efflux pump inhibitors (EPIs). This article presents a molecular study of two quinazoline derivatives, labelled BG1189 and BG1190, proposed as EPIs. In silico approach investigates the pharmacodynamic and pharmacokinetic profile of BG1189 and BG1190 quinazolines. Molecular docking and predicted ADMET features suggest that BG1189 and BG1190 may represent attractive candidates as antimicrobial drugs. UV-Vis absorption spectroscopy was employed to study the time stability of quinazoline solutions in water or in dimethyl sulfoxide (DMSO), in constant environmental conditions, and to determine the influence of usual storage temperature, normal room lighting and laser radiation (photostability) on samples stability. The effects of irradiation on BG1189 and BG1190 molecules were also assessed through Fourier-transform infrared (FTIR) spectroscopy. FTIR spectra showed that laser radiation breaks some chemical bonds affecting the substituents and the quinazoline radical of the compounds. 相似文献
3.
4.
Control over Nanostructures and Associated Mesomorphic Properties of Doped Self‐Assembled Triarylamine Liquid Crystals 下载免费PDF全文
Dr. Yuya Domoto Dr. Eric Busseron Prof. Dr. Mounir Maaloum Dr. Emilie Moulin Prof. Dr. Nicolas Giuseppone 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(5):1938-1948
We have synthesized a series of triarylamine‐cored molecules equipped with an adjacent amide moiety and dendritic peripheral tails in a variety of modes. We show by 1H NMR and UV/Vis spectroscopy that their supramolecular self‐assembly can be promoted in solution upon light stimulation and radical initiation. In addition, we have probed their molecular arrangements and mesomorphic properties in the bulk by integrated studies on their film state by using differential scanning calorimetry (DSC), variable‐temperature polarizing optical microscopy (VT‐POM), variable‐temperature X‐ray diffraction (VT‐XRD), and atomic force microscopy (AFM). Differences in the number and the disposition of the peripheral tails significantly affect their mesomorphic properties associated with their lamellar‐ or columnar‐packed nanostructures, which are based on segregated stacks of the triphenylamine cores and the lipophilic/lipophobic periphery. Such structural tuning is of interest for implementation of these soft self‐assemblies as electroactive materials from solution to mesophases. 相似文献
5.
6.
7.
Foundations of Chemistry - 相似文献
8.
This study compares the physicochemical properties of six electrolytes comprising of three salts: LiFTFSI, NaFTFSI and KFTFSI in two solvent mixtures, the binary (3EC/7EMC) and the ternary (EC/PC/3DMC). The transport properties (conductivity, viscosity) as a function of temperature and concentration were modeled using the extended Jones-Dole-Kaminsky equation, the Arrhenius model, and the Eyring theory of transition state for activated complexes. Results are discussed in terms of ionicity, solvation shell, and cross-interactions between electrolyte components. The application of the six formulated electrolytes in symmetrical activated carbon (AC)//AC supercapacitors (SCs) was characterized by cyclic voltammetry (CV), galvanostatic cycling with potential limitation (GCPL), electrochemical impedance spectroscopy (EIS) and accelerated aging. Results revealed that the geometrical flexibility of the FTFSI anion allows it to access and diffuse easily in AC whereas its counter ions (Li+, Na+ or K+) can remain trapped in porosity. However, this drawback was partially resolved by mixing LiFTFSI and KFTFSI salts in the electrolyte. 相似文献
9.
10.