全文获取类型
收费全文 | 563篇 |
免费 | 28篇 |
国内免费 | 6篇 |
专业分类
化学 | 434篇 |
晶体学 | 2篇 |
力学 | 4篇 |
数学 | 71篇 |
物理学 | 86篇 |
出版年
2023年 | 4篇 |
2022年 | 4篇 |
2021年 | 8篇 |
2020年 | 11篇 |
2019年 | 5篇 |
2018年 | 5篇 |
2017年 | 5篇 |
2016年 | 18篇 |
2015年 | 20篇 |
2014年 | 18篇 |
2013年 | 24篇 |
2012年 | 44篇 |
2011年 | 45篇 |
2010年 | 18篇 |
2009年 | 20篇 |
2008年 | 24篇 |
2007年 | 36篇 |
2006年 | 32篇 |
2005年 | 26篇 |
2004年 | 21篇 |
2003年 | 19篇 |
2002年 | 13篇 |
2001年 | 13篇 |
2000年 | 8篇 |
1999年 | 7篇 |
1998年 | 5篇 |
1997年 | 8篇 |
1996年 | 8篇 |
1995年 | 9篇 |
1994年 | 10篇 |
1993年 | 3篇 |
1992年 | 6篇 |
1990年 | 6篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1981年 | 4篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1972年 | 3篇 |
1929年 | 3篇 |
1910年 | 3篇 |
1907年 | 4篇 |
1906年 | 3篇 |
1905年 | 3篇 |
1904年 | 3篇 |
1901年 | 3篇 |
1885年 | 3篇 |
1868年 | 3篇 |
1864年 | 3篇 |
1862年 | 6篇 |
排序方式: 共有597条查询结果,搜索用时 15 毫秒
81.
Silke Lekaus 《Transactions of the American Mathematical Society》2005,357(11):4647-4659
We characterize those unipotent representations of the fundamental group of a compact Kähler manifold , which correspond to a Higgs bundle whose underlying Higgs field is equal to zero.
The characterization is parallel to the one that R. Hain gave of those unipotent representations of that can be realized as the monodromy of a flat connection on the holomorphically trivial vector bundle.
We see that Hain's result and ours follow from a careful study of Simpson's correspondence between Higgs bundles and local systems.
82.
Barreiro A Hampel S Rümmeli MH Kramberger C Grüneis A Biedermann K Leonhardt A Gemming T Büchner B Bachtold A Pichler T 《The journal of physical chemistry. B》2006,110(42):20973-20977
A new method to grow bulk quantities of single-walled carbon nanotubes (SWCNTs) by a catalytic chemical vapor deposition (CVD) process with the possibility of varying the pressure has been developed and is reported in this paper. Thermal decomposition of ferrocene provides both catalytic particles and carbon sources for SWCNT growth using Ar as a carrier gas. Upon an increase in the pressure, the mean diameter of the SWCNTs decreases. In fact, high abundances of SWCNT with diameters as small as 0.7 nm, which is the limit for stable caps with isolated pentagons, can be obtained. An additional advantage of this method is that as no external carbon sources are required, SWCNT synthesis can be achieved at temperatures as low as 650 degrees C. 相似文献
83.
Effective field theories (EFTs) have been widely used as a framework in order to place constraints on the Planck suppressed Lorentz violations predicted by various models of quantum gravity. There are, however, technical problems in the EFT framework when it comes to ensuring that small Lorentz violations remain small--this is the essence of the "naturalness" problem. Herein we present an "emergent" spacetime model, based on the "analogue gravity" program, by investigating a specific condensed-matter system. Specifically, we consider the class of two-component BECs subject to laser-induced transitions between the components, and we show that this model is an example for Lorentz invariance violation due to ultraviolet physics. Furthermore, our model explicitly avoids the naturalness problem, and makes specific suggestions regarding how to construct a physically reasonable quantum gravity phenomenology. 相似文献
84.
85.
The spectral dynamics of individual bacterial light-harvesting-2 pigment-protein complexes have been studied at 1.4 K. The data provided the spectral diffusion kernel of the optical transitions of the embedded B800 bacteriochlorophyll a pigments. This kernel can be described by either a single Gaussian function or a superposition of Gaussian functions. Moreover, we found that the chromophores interact with two classes of TLSs that can be distinguished by their distance from the chromophore and are most likely located outside (class 1) and inside (class 2) the protein matrix. 相似文献
86.
Corrigendum: Labeling and Selective Inactivation of Gram‐Positive Bacteria Employing Bimodal Photoprobes with Dual Readouts 下载免费PDF全文
Dr. Anzhela Galstyan Dr. Desiree Block Dr. Silke Niemann Dr. Malte C. Grüner Prof.Dr. Stefania Abbruzzetti Michele Oneto Dr. Constantin G. Daniliuc Dr. Sven Hermann Prof.Dr. Cristiano Viappiani Prof.Dr. Michael Schäfers Prof.Dr. Bettina Löffler Priv.‐Doz.Dr. Cristian A. Strassert Dr. Andreas Faust 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(27):9051-9051
87.
Absolute Configuration of Pharmaceutical Research Compounds Determined by X‐ray Powder Diffraction 下载免费PDF全文
M. Sc. Carina Schlesinger M. Sc. Lukas Tapmeyer Dr. Silke D. Gumbert Dr. Dragica Prill Dr. Michael Bolte Prof. Dr. Martin U. Schmidt Dr. Christoph Saal 《Angewandte Chemie (International ed. in English)》2018,57(29):9150-9153
The absolute configuration of active pharmaceutical ingredients (APIs) was determined by generating salts of the active pharmaceutical ingredient (API) with counterions of known chirality, and determining the crystal structures by X‐ray powder diffraction. This approach avoids the (often tedious) growth of single crystals, and is successful with very limited quantities of material (less than 1 mg). The feasibility of the method is demonstrated on five examples, and its limitations are discussed as well. 相似文献
88.
89.
90.
Victor Hugo Infante Patricia Maria Maia Campos Maxim Darvin Silke Lohan Johannes Schleusener Sabine Schanzer Juergen Lademann Martina Meinke 《Photochemistry and photobiology》2023,99(1):176-183
This aim of this study was to evaluate the penetration depth, antioxidant capacity and the clinical efficacy of Melaleuca alternifolia pure essential oil and in a nanoemulsion to prevent skin photoaging. For this, 2% of pure essential oil or 2% of this essential oil in a nanoemulsion were vehiculated in a formulation. The skin penetration was evaluated using confocal Raman microspectroscopy. The radical protection factor was evaluated using electron paramagnetic resonance spectroscopy. For a clinical study, 40 male participants, aged 18–28 years, were enrolled, being divided into three groups: vehicle formulation, M. alternifolia pure essential oil and M. alternifolia Nanoemulsion. All the participants also received a sunscreen SPF 50 to use during the day. Before and after 90 days of study, skin hydrolipidics and morphological characteristics were performed by skin imaging and biophysical techniques. The nanoemulsion presented a lower antioxidant capacity and a higher penetration through the stratum corneum, reaching the viable epidermis, improving the stratum granulosum morphology. The groups presented an increase in the papillary depth, improving in the dermis echogenicity and the collagen fibers. Melaleuca alternifolia essential provides the potential to improve photoaged skin, being the application of nanoemulsion able to reach deeper skin layers. 相似文献