全文获取类型
收费全文 | 2494篇 |
免费 | 65篇 |
国内免费 | 8篇 |
专业分类
化学 | 1694篇 |
晶体学 | 7篇 |
力学 | 32篇 |
数学 | 565篇 |
物理学 | 269篇 |
出版年
2020年 | 45篇 |
2019年 | 29篇 |
2018年 | 17篇 |
2017年 | 25篇 |
2016年 | 42篇 |
2015年 | 68篇 |
2014年 | 52篇 |
2013年 | 92篇 |
2012年 | 93篇 |
2011年 | 99篇 |
2010年 | 75篇 |
2009年 | 58篇 |
2008年 | 119篇 |
2007年 | 110篇 |
2006年 | 95篇 |
2005年 | 102篇 |
2004年 | 79篇 |
2003年 | 63篇 |
2002年 | 50篇 |
2001年 | 22篇 |
2000年 | 32篇 |
1999年 | 25篇 |
1998年 | 30篇 |
1997年 | 20篇 |
1996年 | 16篇 |
1995年 | 24篇 |
1994年 | 23篇 |
1993年 | 33篇 |
1992年 | 26篇 |
1991年 | 17篇 |
1989年 | 25篇 |
1988年 | 27篇 |
1987年 | 29篇 |
1985年 | 33篇 |
1984年 | 46篇 |
1983年 | 23篇 |
1982年 | 19篇 |
1981年 | 31篇 |
1980年 | 36篇 |
1979年 | 22篇 |
1978年 | 21篇 |
1977年 | 22篇 |
1976年 | 22篇 |
1975年 | 23篇 |
1974年 | 25篇 |
1967年 | 16篇 |
1966年 | 16篇 |
1965年 | 16篇 |
1964年 | 16篇 |
1956年 | 24篇 |
排序方式: 共有2567条查询结果,搜索用时 234 毫秒
101.
Petr Kluson Stepan Kment Magdalena Morozova Pavel Dytrych Stanislav Hejda Morwenna Slater Zdenek Hubicka Josef Krysa 《Chemical Papers》2012,66(5):446-460
Chemistry and physics of thin semiconducting layers of various types are subjects of intense research. Especially when nanotechnology
methods such as self-assembly are involved, amazing structural and/or functional properties may appear. Also modern physical
methods using variously organized plasma arrangements are able to produce uniform structures with distinctive functionality.
In this review, based virtually on our own work, discussions on the preparation, structure, morphology, and function of titanium(IV)
oxide nanoscopic thin films are presented. It was shown that structurally and functionally similar titanium(IV) oxide films
can be prepared via completely different preparation techniques. Function tests were arranged as “primary”, covering the assessment
of the light induced charge separation efficiency, and “secondary”, based on photocatalytic surface oxidations. 相似文献
102.
Josef Bemelmans Giovanni P. Galdi Mads Kyed 《Journal of Mathematical Fluid Mechanics》2012,14(4):751-770
We consider the hydrostatic configuration of a body floating freely on a liquid. Under the influence of gravitational and capillary forces there exists an equilibrium solution with contact angle π/2. This solution is the minimizer of a variational problem with an obstacle condition; the corresponding free boundary consists of the curve where the capillary surface meets the floating body. 相似文献
103.
Patrick Achenbach Sebastian Bleser Josef Pochodzalla Alicia Sanchez Lorente Marcel Steinen 《Hyperfine Interactions》2012,208(1-3):99-104
Samples obtained as a result of the valleriite synthesis process under different conditions (temperature and proportion Cu:Fe:Mg in the initial mixture) were investigated by 57Fe M?ssbauer spectroscopy with attraction data of X-ray diffraction. Parameters of hyperfine interactions for valleriite were determined and crystal chemical identification of 57Fe subspectra was carried out. It was found that valleriite was formed in samples synthesized at 150°C and 180°C and not formed in samples synthesized at 250°C. 相似文献
104.
Miroslav Jelínek Petr Písařík Tomáš Kocourek Josef Zemek Jaroslav Lukeš 《Applied Physics A: Materials Science & Processing》2013,110(4):943-947
A hybrid PLD system with ion bombardment of films was developed. Growing DLC films were modified during the laser deposition (10 J?cm?2) by argon ions with energy in the range from 40 eV to 210 eV and cathode current of 0.15 A and 0.5 A. The content of sp2 “graphitic” and sp3 “diamond” bonds was measured using XPS. Sp3 bonds changed from 60 % to 81 %. We found the highest sp3 content for energy of 40 eV. Hardness (and reduced Young’s modulus) were determined by nanoindentation and reached 49 GPa (277 GPa). Film adhesion was studied using the scratch test and was up to 14 N for titanium substrates. Relations among deposition conditions and measured properties are presented. 相似文献
105.
106.
107.
The effect of non‐thermal plasma generated by the direct current (DC) corona discharge in the mode of transition spark is studied on a yeast Saccharomyces cerevisiae. The exposure to plasma increases production of reactive oxygen species (ROS) in cells, possibly causing the induction of apoptosis. To clarify the mechanism of apoptosis, its induction is tested not only on a wild strain of S. cerevisiae, but also on mutant strains: A deletion mutant Δyca1 without yeast metacaspase proves that in S. cerevisiae the apoptosis occurs partly by the caspase‐independent pathway. A petite strains with mutation in the mitochondria do not show pronounced ROS formation, but in spite of this, apoptosis is detected. Hence, mitochondrial ROS probably do not play an important role in induction of apoptosis. 相似文献
108.
Ryan Guterman Valerio Molinari Elinor Josef 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(37):13178-13184
Ionic liquid lignins are prepared from sodium lignosulfonate by a cation exchange reaction and display glass transition temperatures as low as ?13 °C. Diethyleneglycol‐functionalized protic cations inhibit lignin aggregation to produce a free‐flowing “ionic liquid lignin”, despite it being a high‐molecular‐weight polyelectrolyte. Through this approach, the properties of both lignin and ionic liquids are combined to create a dispersant and binder for cellulose+gluten mixtures to produce small microphases. Biocomposite testing pieces are produced by hot‐pressing this mixture, yielding a material with fewer defects and improved toughness in comparison to other lignins. The use of unmodified lignosulfonate, acetylated lignosulfonate, or free ionic liquid for similar materials production yields poorer substances because of their inability to maximize interfacial contact and complexation with cellulose and proteins. 相似文献
109.
110.
Dr. Jana Hudecová Dr. Josef Kapitán Prof. Martin Dračínský Pavel Michal Dr. Václav Profant Prof. Petr Bouř 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(59):e202202045
The histidine residue has an exceptional affinity for metals, but solution structure of its complexes are difficult to study. For zinc and nickel complexes, Raman and Raman optical activity (ROA) spectroscopy methods to investigate the link between spectral shapes and the geometry were used. The spectra were recorded and interpreted on the basis of ionic equilibria, molecular dynamics, ab initio molecular dynamics, and density functional theory. For zwitterionic histidine the dominant tautomer was determined by the decomposition of experimental spectra into calculated subspectra. An octahedral structure was found to prevail for the ZnHis2 complex in solution, in contrast to a tetrahedral arrangement in the crystal phase. The solution geometry of NiHis2 is more similar to the octahedral structure found by X-ray. The Raman and ROA structural determinations of metal complexes are dependent on extensive computations, but reveal unique information about the studied systems. 相似文献