全文获取类型
收费全文 | 855篇 |
免费 | 30篇 |
国内免费 | 1篇 |
专业分类
化学 | 723篇 |
晶体学 | 3篇 |
力学 | 9篇 |
综合类 | 1篇 |
数学 | 54篇 |
物理学 | 96篇 |
出版年
2022年 | 5篇 |
2021年 | 4篇 |
2020年 | 10篇 |
2019年 | 6篇 |
2018年 | 8篇 |
2016年 | 16篇 |
2015年 | 15篇 |
2014年 | 35篇 |
2013年 | 35篇 |
2012年 | 32篇 |
2011年 | 57篇 |
2010年 | 24篇 |
2009年 | 32篇 |
2008年 | 37篇 |
2007年 | 58篇 |
2006年 | 38篇 |
2005年 | 46篇 |
2004年 | 30篇 |
2003年 | 34篇 |
2002年 | 41篇 |
2001年 | 15篇 |
2000年 | 13篇 |
1999年 | 16篇 |
1998年 | 10篇 |
1997年 | 14篇 |
1996年 | 18篇 |
1995年 | 18篇 |
1994年 | 16篇 |
1993年 | 14篇 |
1992年 | 5篇 |
1991年 | 20篇 |
1990年 | 9篇 |
1989年 | 11篇 |
1988年 | 12篇 |
1987年 | 4篇 |
1986年 | 15篇 |
1984年 | 11篇 |
1983年 | 6篇 |
1982年 | 11篇 |
1981年 | 9篇 |
1980年 | 8篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 8篇 |
1976年 | 10篇 |
1975年 | 9篇 |
1974年 | 3篇 |
1971年 | 4篇 |
1967年 | 3篇 |
1863年 | 3篇 |
排序方式: 共有886条查询结果,搜索用时 13 毫秒
41.
David Rombach Hans‐Achim Wagenknecht 《Angewandte Chemie (International ed. in English)》2020,59(1):300-303
SF6 was applied as pentafluorosulfanylation reagent to prepare ethers with a vicinal SF5 substituent through a one‐step method involving photoredox catalysis. This method shows a broad substrate scope with respect to applicable alcohols for the conversion of α‐methyl and α‐phenyl styrenes. The products bear a new structural motif with two functional groups installed in one step. The alkoxy group allows elimination and azidation as further transformations into valuable pentafluorosulfanylated compounds. These results confirm that non‐toxic SF6 is a useful SF5 transfer reagent if properly activated by photoredox catalysis, and toxic reagents are completely avoided. In combination with light as an energy source, a high level of sustainability is achieved. Through this method, the proposed potential of the SF5 substituent in medicinal chemistry, agrochemistry, and materials chemistry may be exploited in the future. 相似文献
42.
Johanne Heitmann Solheim Boris Zimmermann Valeria Tafintseva Simona Dzurendov Volha Shapaval Achim Kohler 《Molecules (Basel, Switzerland)》2022,27(6)
Extended multiplicative signal correction (EMSC) is a widely used preprocessing technique in infrared spectroscopy. EMSC is a model-based method favored for its flexibility and versatility. The model can be extended by adding constituent spectra to explicitly model-known analytes or interferents. This paper addresses the use of constituent spectra and demonstrates common pitfalls. It clarifies the difference between analyte and interferent spectra, and the importance of orthogonality between model spectra. Different normalization approaches are discussed, and the importance of weighting in the EMSC is demonstrated. The paper illustrates how constituent analyte spectra can be estimated, and how they can be used to extract additional information from spectral features. It is shown that the EMSC parameters can be used in both regression tasks and segmentation tasks. 相似文献
43.
44.
45.
46.
47.
48.
49.
Ana Leonor Rivera Miguel Gómez-Lim Francisco Fernández Achim M. Loske 《Physics of life reviews》2012,9(3):308-345
Production of transgenic plants is a routine process for many crop species. Transgenes are introduced into plants to confer novel traits such as improved nutritional qualities, tolerance to pollutants, resistance to pathogens and for studies of plant metabolism. Nowadays, it is possible to insert genes from plants evolutionary distant from the host plant, as well as from fungi, viruses, bacteria and even animals. Genetic transformation requires penetration of the transgene through the plant cell wall, facilitated by biological or physical methods. The objective of this article is to review the state of the art of the physical methods used for genetic plant transformation and to describe the basic physics behind them. 相似文献
50.
Instruments for surgical and dental application based on oscillatory mechanics submit unwanted vibrations to the operator’s hand. Frequently the weight of the instrument’s body is increased to dampen its vibration. Based on recent research regarding the optimization of granular damping we developed a prototype granular damper that attenuates the vibrations of an oscillatory saw twice as efficiently as a comparable solid mass. 相似文献