全文获取类型
收费全文 | 10072篇 |
免费 | 1351篇 |
国内免费 | 1384篇 |
专业分类
化学 | 9746篇 |
晶体学 | 80篇 |
力学 | 24篇 |
综合类 | 90篇 |
数学 | 5篇 |
物理学 | 2862篇 |
出版年
2024年 | 8篇 |
2023年 | 98篇 |
2022年 | 226篇 |
2021年 | 358篇 |
2020年 | 404篇 |
2019年 | 455篇 |
2018年 | 340篇 |
2017年 | 382篇 |
2016年 | 539篇 |
2015年 | 509篇 |
2014年 | 539篇 |
2013年 | 960篇 |
2012年 | 808篇 |
2011年 | 615篇 |
2010年 | 599篇 |
2009年 | 669篇 |
2008年 | 633篇 |
2007年 | 689篇 |
2006年 | 632篇 |
2005年 | 546篇 |
2004年 | 464篇 |
2003年 | 389篇 |
2002年 | 279篇 |
2001年 | 189篇 |
2000年 | 198篇 |
1999年 | 151篇 |
1998年 | 154篇 |
1997年 | 151篇 |
1996年 | 116篇 |
1995年 | 148篇 |
1994年 | 114篇 |
1993年 | 103篇 |
1992年 | 79篇 |
1991年 | 67篇 |
1990年 | 43篇 |
1989年 | 31篇 |
1988年 | 29篇 |
1987年 | 36篇 |
1986年 | 10篇 |
1985年 | 11篇 |
1984年 | 8篇 |
1983年 | 3篇 |
1982年 | 7篇 |
1981年 | 2篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1978年 | 4篇 |
1977年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 156 毫秒
101.
Selective Probing of Gaseous Ammonia Using Red‐Emitting Carbon Dots Based on an Interfacial Response Mechanism 下载免费PDF全文
Dr. Bang‐Ping Jiang Bo Zhou Prof. Dr. Xing‐Can Shen Yun‐Xiang Yu Dr. Shi‐Chen Ji Chang‐Chun Wen Prof. Dr. Hong Liang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(52):18993-18999
Solid‐state fluorescence sensing is one of the most appealing detection techniques because of its simplicity and convenience in practical operation. Herein, we report the development of a red‐emitting carbon dots (RCDs)‐based material as a solid‐state fluorescence sensor for the selective probing of gaseous ammonia. The RCDs were prepared by a low‐cost, one‐step carbonization method using sugar cane bagasse as the carbon precursor. The pristine RCDs were then directly coated on polyvinylidene fluoride membrane to produce a new fluorescence sensor capable of selectively distinguishing toxic gaseous ammonia from other analyte vapors through sensitive fluorescence quenching with a low detection limit. More importantly, the interfacial response mechanism occurring on the surface of the RCDs has been studied by X‐ray photoelectron spectroscopy, Fourier‐transform infrared spectroscopy, and Raman measurements. The results indicate that fluorescence quenching in the RCDs might result from ammonia‐induced Michael addition through insertion of N into the C?C group and deprotonation of the carboxyl group. To the best of our knowledge, this is the first report that provides clear insight into the mechanism of surface chemistry on CDs in the solid state. 相似文献
102.
Frontispiece: New Dual Fluorescent Probe for Simultaneous Biothiol and Phosphate Bioimaging 下载免费PDF全文
103.
Inside Cover: A Boron Dipyrromethene (BODIPY)‐Based CuII–Bipyridine Complex for Highly Selective NO Detection (Chem. Eur. J. 44/2015) 下载免费PDF全文
104.
A novel method is developed for the direct determination of naphazoline hydrochloride(NAP) and pyridoxine hydrochloride(VB6) in commercial eye drops. By using excitation–emission matrix(EEM)fluorescence coupled with second-order calibration method based on the alternating trilinear decomposition(ATLD) algorithm, the proposed approach can achieve quantitative analysis successfully even in the presence of unknown and uncalibrated interferences. The method shows good linearity for NAP and VB6 with correlation coefficients greater than 0.99. The results were in good agreement with the labeled contents. To further confirm the feasibility and reliability of the proposed method, the same batch samples were analyzed by multiple reaction monitoring(MRM) based on LC–MS/MS method.T-test demonstrated that there are no significant differences between the prediction results of the two methods. The satisfactory results obtained in this work indicate that the use of the second-order calibration method coupled with the EEM is a promising tool for industrial quality control and pharmaceutical analysis due to its advantages of high sensitivity, low-cost and simple implementation. 相似文献
105.
106.
107.
High‐Contrast Red–Green–Blue Tricolor Fluorescence Switching in Bicomponent Molecular Film 下载免费PDF全文
Hyeong‐Ju Kim Dr. Dong Ryeol Whang Chong Han Lee Prof. Soo Young Park 《Angewandte Chemie (International ed. in English)》2015,54(14):4330-4333
Highly efficient red–green–blue (RGB) tricolor luminescence switching was demonstrated in a bicomponent solid film consisting of (2Z,2′Z)‐2,2′‐(1,4‐phenylene)bis(3‐(4‐butoxyphenyl)acrylonitrile) (DBDCS) and (2Z,2′Z)‐3,3′‐(2,5‐bis(6‐(9H‐carbazol‐9‐yl)hexyloxy)‐1,4‐phenylene)bis(2‐(3,5‐bis(trifluoromethyl)phenyl)acrylonitrile) (m‐BHCDCS). Reversible RGB luminescence switching with a high ratiometric color contrast (λem=594, 527, 458 nm for red, green, and blue, respectively) was realized by different external stimuli such as heat, solvent vapor exposure, and mechanical force. It was shown that Förster resonance energy transfer in the bicomponent mixture could be efficiently switched on and off through supramolecular control. 相似文献
108.
Chun‐Feng Wang Dr. Ren‐Fu Li Prof. Dr. Xue‐Yuan Chen Dr. Rong‐Jia Wei Prof. Dr. Lan‐Sun Zheng Prof. Dr. Jun Tao 《Angewandte Chemie (International ed. in English)》2015,54(5):1574-1577
Hybrid materials integrated with a variety of physical properties, such as spin crossover (SCO) and fluorescence, may show synergetic effects that find applications in many fields. Herein we demonstrate a promising post‐synthetic approach to achieve such materials by grafting fluorophores (1‐pyrenecarboxaldehyde and Rhodamine B) on one‐dimensional SCO FeII structures. The resulting hybrid materials display expected one‐step SCO behavior and fluorescent properties, in particular showing a coupling between the transition temperature of SCO and the temperature where the fluorescent intensity reverses. Consequently, synergetic effect between SCO and fluorescence is incorporated into materials despite different fluorophores. This study provides an effective strategy for the design and development of novel magnetic and optical materials. 相似文献
109.
High‐Resolution Single‐Molecule Fluorescence Imaging of Zeolite Aggregates within Real‐Life Fluid Catalytic Cracking Particles 下载免费PDF全文
Zoran Ristanović Dr. Marleen M. Kerssens Alexey V. Kubarev Frank C. Hendriks Dr. Peter Dedecker Prof. Dr. Johan Hofkens Prof. Dr. Maarten B. J. Roeffaers Prof. Dr. Bert M. Weckhuysen 《Angewandte Chemie (International ed. in English)》2015,54(6):1836-1840
Fluid catalytic cracking (FCC) is a major process in oil refineries to produce gasoline and base chemicals from crude oil fractions. The spatial distribution and acidity of zeolite aggregates embedded within the 50–150 μm‐sized FCC spheres heavily influence their catalytic performance. Single‐molecule fluorescence‐based imaging methods, namely nanometer accuracy by stochastic chemical reactions (NASCA) and super‐resolution optical fluctuation imaging (SOFI) were used to study the catalytic activity of sub‐micrometer zeolite ZSM‐5 domains within real‐life FCC catalyst particles. The formation of fluorescent product molecules taking place at Brønsted acid sites was monitored with single turnover sensitivity and high spatiotemporal resolution, providing detailed insight in dispersion and catalytic activity of zeolite ZSM‐5 aggregates. The results point towards substantial differences in turnover frequencies between the zeolite aggregates, revealing significant intraparticle heterogeneities in Brønsted reactivity. 相似文献
110.
双光子荧光显微成像兼具诸如近红外激发、暗场成像、避免荧光漂白和光致毒、定靶激发、高横向分辨率与纵向分辨率、降低生物组织吸光系数及降低组织自发荧光干扰等特点,显著地优于单光子荧光显微成像,为生命科学研究提供了更为便利的工具.因此双光子荧光探针适合于生物检测与成像.制备了衍生于二苯代乙烯的双光子荧光银离子探针,此探针以拥有异常大的双光子吸收截面(6TPA)的4-甲基-2,5-二氰基-4'-氨基二苯乙烯(DCS)作为双光子荧光母体,以6-芳基-3,9-二硫-6-氮杂癸烷(TAU)为Ag+配体.探针显示了大的δTPA(在MeCN中,950 GM)、对银离子有高的灵敏性与选择性、强的双光子荧光(790 nm激光激发时).探针的络合常数为IgK=5.76±0.05.探针能选择性地检测和成像活细胞中的游离Ag+,可用于细胞中微量Ag+的分析检测与成像.此探针为开发理想的双光子荧光探针提供了可供借鉴的平台. 相似文献