全文获取类型
收费全文 | 3846篇 |
免费 | 302篇 |
国内免费 | 18篇 |
专业分类
化学 | 2872篇 |
晶体学 | 13篇 |
力学 | 86篇 |
数学 | 531篇 |
物理学 | 664篇 |
出版年
2023年 | 55篇 |
2022年 | 85篇 |
2021年 | 127篇 |
2020年 | 181篇 |
2019年 | 197篇 |
2018年 | 91篇 |
2017年 | 83篇 |
2016年 | 224篇 |
2015年 | 172篇 |
2014年 | 190篇 |
2013年 | 237篇 |
2012年 | 343篇 |
2011年 | 352篇 |
2010年 | 196篇 |
2009年 | 150篇 |
2008年 | 261篇 |
2007年 | 215篇 |
2006年 | 188篇 |
2005年 | 138篇 |
2004年 | 103篇 |
2003年 | 70篇 |
2002年 | 59篇 |
2001年 | 37篇 |
2000年 | 32篇 |
1999年 | 25篇 |
1998年 | 27篇 |
1997年 | 15篇 |
1996年 | 25篇 |
1995年 | 26篇 |
1994年 | 19篇 |
1993年 | 15篇 |
1992年 | 17篇 |
1991年 | 14篇 |
1990年 | 16篇 |
1989年 | 17篇 |
1988年 | 5篇 |
1987年 | 12篇 |
1986年 | 10篇 |
1984年 | 11篇 |
1983年 | 8篇 |
1982年 | 7篇 |
1981年 | 11篇 |
1980年 | 5篇 |
1979年 | 10篇 |
1978年 | 12篇 |
1977年 | 8篇 |
1976年 | 8篇 |
1975年 | 11篇 |
1974年 | 9篇 |
1973年 | 8篇 |
排序方式: 共有4166条查询结果,搜索用时 15 毫秒
971.
972.
973.
Ingmar Krabbes Wilhelm Seichter Karsten Gloe 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(5):e178-e178
The title compound, [Ni{N(CH2CH2OH)3}2](CH3COO)2, was prepared and the structure determined. It is isostructural with the copper(II) analogue. 相似文献
974.
Philipp Schulze Martin Link Marcel Schulze Sebastian Thuermann Otto S. Wolfbeis Detlev Belder 《Electrophoresis》2010,31(16):2749-2753
In this study, we present a novel amino‐reactive fluorescence marker (referred to as UR‐431), which is well suited for electrophoretic techniques. A main feature of this marker is its weakly basic behavior when conjugated to analytes. Labeled primary amines exhibit a positive net charge and accordingly a cathodic mobility below a pH of 2.4. The label features a pH‐independent fluorescence emission and is thus very interesting for electrophoretic applications such as IEF. The absorption maximum of this yellow daylight chromophore is at 431 nm, whereas fluorescence emission peaks at 537 nm (quantum yield≈0.1). The label was successfully conjugated to amines, peptides and proteins and separated via CE and MCE. The on‐chip detection limit of labeled lysine using a mercury‐lamp‐based fluorescence microscope was determined as 12 nM. An important feature of the new label is that it effects only a subtle change of the pI of proteins compared with common anionic labels, e.g. FITC. pI values of proteins were investigated by comparing native proteins and labeled proteins in CIEF. UR‐431 was also applied to sensitive detection of amines and peptides in MCE. 相似文献
975.
976.
977.
978.
979.
Sebastian Werner Clarissa Glaser Thomas Kasper Trung Nghia Nguyên Lê Prof. Dr. Silvia Gross Prof. Dr. Bernd M. Smarsly 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(3):e202103437
The precise detection of the toxic gas H2S requires reliable sensitivity and specificity of sensors even at minute concentrations of as low as 10 ppm, the value corresponding to typical exposure limits. CuO can be used for H2S dosimetry, based on the formation of conductive CuS and the concomitant significant increase in conductance. In theory, at elevated temperature the reaction is reversed and CuO is formed, ideally enabling repeated and long-term use of one sensor. Yet, the performance of CuO tends to drop upon cycling. Utilizing defined CuO nanorods we thoroughly elucidated the associated detrimental chemical changes directly on the sensors, by Raman and electron microscopy analysis of each step during sensing (CuO→CuS) and regeneration (CuS→CuO) cycles. We find the decrease in the sensing performance is mainly caused by the irreversible formation of CuSO4 during regeneration. The findings allowed us to develop strategies to reduce CuSO4 formation and thus to substantially maintain the sensing stability even for repeated cycles. We achieved CuO-based dosimeters possessing a response time of a few minutes only, even for 10 ppm H2S, and prolonged life-time. 相似文献
980.
Dr. Alejandro Cadranel Lisa Gravogl Prof. Dr. Dominik Munz Prof. Dr. Karsten Meyer 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(41):e202200269
We report high-valent iron complexes supported by N-heterocyclic carbene (NHC)-anchored, bis-phenolate pincer ligands that undergo ligand-to-metal charge transfer (LMCT) upon photoexcitation. The resulting excited states – with a lifetime in the picosecond range – feature a ligand-based, mixed-valence system and intense intervalence charge transfer bands in the near-infrared region. Upon oxidation of the complex, corresponding intervalence charge transfer absorptions are also observed in the ground state. We suggest that the spectroscopic hallmarks of such LMCT states provide useful tools to decipher excited-state decay mechanisms in high-valent NHC complexes. Our observations further indicate that NHC-anchored, bis-phenolate pincer ligands are not sufficiently strong donors to prevent the population of excited metal-centered states in high-valent iron complexes. 相似文献