全文获取类型
收费全文 | 241篇 |
免费 | 18篇 |
专业分类
化学 | 202篇 |
力学 | 1篇 |
数学 | 11篇 |
物理学 | 45篇 |
出版年
2021年 | 6篇 |
2020年 | 8篇 |
2019年 | 6篇 |
2018年 | 1篇 |
2017年 | 4篇 |
2016年 | 21篇 |
2015年 | 12篇 |
2014年 | 12篇 |
2013年 | 15篇 |
2012年 | 21篇 |
2011年 | 18篇 |
2010年 | 8篇 |
2009年 | 14篇 |
2008年 | 18篇 |
2007年 | 21篇 |
2006年 | 17篇 |
2005年 | 14篇 |
2004年 | 6篇 |
2003年 | 7篇 |
2002年 | 16篇 |
2001年 | 2篇 |
2000年 | 4篇 |
1999年 | 1篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1993年 | 1篇 |
1989年 | 1篇 |
1986年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有259条查询结果,搜索用时 15 毫秒
251.
We propose a cavity experiment to search for low mass extra U(1) gauge bosons with gauge-kinetic mixing with the ordinary photon, so-called paraphotons. The setup consists of two microwave cavities shielded from each other. In one cavity, paraphotons are produced via photon–paraphoton oscillations. The second, resonant, cavity is then driven by the paraphotons that permeate the shielding and reconvert into photons. This setup resembles the classic “light shining through a wall” setup. However, the high quality factors achievable for microwave cavities and the good sensitivity of microwave detectors allow for a projected sensitivity for photon–paraphoton mixing of the order of χ∼10−12–10−8, for paraphotons with masses in the μeV to meV range—exceeding the current laboratory and astrophysics-based limits by several orders of magnitude. Therefore, this experiment bears significant discovery potential for hidden sector physics. 相似文献
252.
If there is a light Abelian gauge boson gamma' in the hidden sector its kinetic mixing with the photon can produce a hidden cosmic microwave background (HCMB). For meV masses, resonant oscillations gamma<-->gamma' happen after big bang nucleosynthesis (BBN) but before CMB decoupling, increasing the effective number of neutrinos Nnu(eff) and the baryon to photon ratio, and distorting the CMB blackbody spectrum. The agreement between BBN and CMB data provides new constraints. However, including Lyman-alpha data, Nnu(eff) > 3 is preferred. It is tempting to attribute this effect to the HCMB. The interesting parameter range will be tested in upcoming laboratory experiments. 相似文献
253.
254.
Wolfgang Jeitschko Joerg H. Albering Reinhold Brink Ursula Jakubowski‐Ripke Elke J. Reinbold 《ChemInform》2015,46(1):no-no
The new ternary phosphides ScFe5P3 (I), Sc(Ta0.18Fe0.82)Fe4P3 (II), ZrFe5P3 (III), ScRu6P4 (IV), ErRu6P4 (V), ZrCr6P4 (VI), Nd2Ru12P7 (VII), and U2Mo30P19 (VIII) are prepared from mixtures of the elements in most cases with elemental Sn as a flux (alumina crucibles, 650—950 °C, 7—10 d). 相似文献
255.
256.
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option. 相似文献
257.
Gerald Gerlach Margarita Guenther Gunnar Suchaneck Joerg Sorber Karl-Friedrich Arndt Andreas Richter 《Macromolecular Symposia》2004,210(1):403-410
In the present work, pH-sensitive poly(vinyl alcohol)/poly(acrylic acid) (PVA/PAA) blends as well as hydrogels based on poly(N-isopropylacrylamide) (PNIPAAm), which are sensitive to organic solvent concentration in aqueous solutions, were used in silicon micromachined sensors. A sensitivity of approximately 15 mV/pH was obtained for a pH sensor with a 50 μm thick PVA/PAA hydrogel layer in a pH range above the acid exponent of acrylic acid (pKa=4.7). The output voltage versus pH-value characteristics and the long-term signal stability of hydrogel-based sensors were investigated and the measurement conditions necessary for high signal reproducibility were determined. The influence of the preparation conditions of the hydrogel films on the sensitivity and response time of the chemical and pH sensors is discussed. 相似文献
258.
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option. 相似文献
259.
Frederik Bachhuber Joerg von Appen Richard Dronskowski Peer Schmidt Tom Nilges Arno Pfitzner Richard Weihrich 《ChemInform》2015,46(3):no-no
A complete stability range of known and new crystalline allotropes of phosphorus including recently discovered tubular modifications and not‐yet‐known crystal structures of [P12] nanorods, and not‐yet‐isolated [P14] nanorods is given using quantum chemical DFT calculations. 相似文献