全文获取类型
收费全文 | 2527篇 |
免费 | 79篇 |
国内免费 | 7篇 |
专业分类
化学 | 1962篇 |
晶体学 | 7篇 |
力学 | 24篇 |
数学 | 306篇 |
物理学 | 314篇 |
出版年
2023年 | 14篇 |
2022年 | 15篇 |
2021年 | 32篇 |
2020年 | 58篇 |
2019年 | 39篇 |
2018年 | 15篇 |
2017年 | 13篇 |
2016年 | 73篇 |
2015年 | 63篇 |
2014年 | 78篇 |
2013年 | 131篇 |
2012年 | 160篇 |
2011年 | 164篇 |
2010年 | 89篇 |
2009年 | 79篇 |
2008年 | 145篇 |
2007年 | 119篇 |
2006年 | 120篇 |
2005年 | 126篇 |
2004年 | 133篇 |
2003年 | 93篇 |
2002年 | 98篇 |
2001年 | 48篇 |
2000年 | 44篇 |
1999年 | 35篇 |
1998年 | 28篇 |
1997年 | 38篇 |
1996年 | 38篇 |
1995年 | 38篇 |
1994年 | 46篇 |
1993年 | 42篇 |
1992年 | 37篇 |
1991年 | 22篇 |
1990年 | 27篇 |
1989年 | 28篇 |
1988年 | 29篇 |
1987年 | 16篇 |
1985年 | 29篇 |
1984年 | 16篇 |
1983年 | 10篇 |
1982年 | 20篇 |
1981年 | 19篇 |
1980年 | 12篇 |
1979年 | 21篇 |
1978年 | 12篇 |
1977年 | 18篇 |
1976年 | 14篇 |
1975年 | 11篇 |
1973年 | 9篇 |
1970年 | 10篇 |
排序方式: 共有2613条查询结果,搜索用时 0 毫秒
991.
992.
Dr. Daniela Hermann Dr. Heidi A. Schwartz Melanie Werker Prof. Dr. Dominik Schaniel Prof. Dr. Uwe Ruschewitz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(14):3606-3616
Fifteen new photochromic hybrid materials were synthesized by gas phase loading of fluorinated azobenzenes, namely ortho-tetrafluoroazobenzene (tF-AZB), 4H,4H′-octafluoroazobenzene (oF-AZB), and perfluoroazobenzene (pF-AZB), into the pores of the well-known metal-organic frameworks MOF-5, MIL-53(Al), MIL-53(Ga), MIL-68(Ga), and MIL-68(In). Their composition was analysed by elemental (CHNS) and DSC/TGA. For pF-AZB0.34@MIL-53(Al), a structural model based on high-resolution synchrotron powder diffraction data was developed and the host-guest and guest-guest interactions were elucidated from this model. These interactions of O−H⋅⋅⋅F and π⋅⋅⋅π type were confirmed by significant shifts of the O−H frequencies in loaded and unloaded MOFs of the MIL-53 and MIL-68 series. Most remarkably, all of the synthesized F-AZB@MOF systems can be switched with visible light, and some of them show almost quantitative (>95 %) photo-isomerization between its E and Z forms with no significant fatigue after repeated switching cycles. 相似文献
993.
994.
Helge Jochens Dipl.‐Biochem. Konstanze Stiba Dr. Christopher Savile Dr. Ryota Fujii Dr. Juin‐Guo Yu Tatsiana Gerassenkov Romas J. Kazlauskas Prof. Uwe T. Bornscheuer Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(19):3532-3535
Entering the fold : A common structural motif in hydrolytic enzymes is the α,β‐hydrolase fold. The interconversion of one enzyme into another by introduction of mechanistically important residues is not enough; only substitution of a loop allows epoxide hydrolase activity in the esterase scaffold to be formed (see picture; structure comparison of epoxide hydrolases (green) with the esterase (orange)). The result is an enantioselective chimeric enzyme.
995.
996.
Ulf Johansson Tutti Johansson Falk Simon Leemann Uwe Mueller Magnus Sjöström Marjolein Thunnissen 《Synchrotron Radiation News》2016,29(6):16-25
In a ceremony held on June 21, the brightest day of the year in the northern hemisphere, Swedish Prime Minister Stefan Löfven and H.M. King Carl XVI Gustaf, together with Director Christoph Quitmann, inaugurated MAX IV Laboratory in the presence of about 500 staff, funders, stakeholders, and guests from all over the world. 相似文献
997.
998.
999.
Marcus Lederer Dr. Uwe Hahn Jean‐Marc Strub Dr. Sarah Cianférani Dr. Alain Van Dorsselaer Dr. Jean‐François Nierengarten Prof. Dr. Tomas Torres Prof. Dr. Dirk M. Guldi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(6):2051-2059
Self‐assembly driven by crown ether complexation of zinc phthalocyanines equipped with one 18‐crown‐6 moiety and fullerenes bearing an ammonium head group afforded a novel donor–acceptor hybrid. In reference experiments, fullerenes containing a Boc‐protected amine functionality have been probed. The circumvention of zinc phthalocyanine aggregation is important for the self‐assembly, which required the addition of pyridine. From absorption and fluorescence titration assays, which provided sound and unambiguous evidence for mutual interactions between the electron donor and the electron acceptor within the hybrids, association constants in the order of 8.0×105 m ?1 have been derived. The aforementioned is based on 1:1 stoichiometries, which have been independently confirmed by Job's plot measurements. In the excited state, which has been examined by transient absorption experiments, intermolecular charge separation evolves from the photoexcited zinc phthalocyanine to the fullerene subunit and leads to short‐lived charge‐separated states. Interestingly, photoexcitation of zinc phthalocyanine dimers/aggregates can also be followed by an intermolecular charge separation between vicinal phthalocyanines. These multicomponent supramolecular ensembles have also been shown by in‐depth electrospray ionization mass spectrometry (ESI‐MS) studies, giving rise to the formation and detection of a variety of non‐covalently linked species. 相似文献
1000.
Sebastian Hahn Philipp Biegger Markus Bender Dr. Frank Rominger Prof. Uwe H. F. Bunz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(3):869-873
Thermal condensation of 2,3‐diamino‐1,4‐(bistriisopropylsilylethynyl)benzene, ‐naphthalene,‐anthracene, and ‐benzothiadiazole substrates with 1,2‐naphthalenedione forms bent benzophenazine‐type heteroarenes in a one‐step reaction in good to excellent yields. The targets are investigated by UV/Vis spectroscopy, cyclic voltammetry, and single‐crystal X‐ray crystallography. The packing of the targets in the solid state follows either a herringbone or a brick wall motif. In the case of 8,13‐bis(triisopropylsilylethynyl)dibenzo[a,i]phenazine, polymorphs with either packing result. 相似文献