全文获取类型
收费全文 | 182篇 |
免费 | 3篇 |
专业分类
化学 | 87篇 |
力学 | 3篇 |
数学 | 43篇 |
物理学 | 52篇 |
出版年
2024年 | 1篇 |
2023年 | 2篇 |
2022年 | 13篇 |
2021年 | 12篇 |
2020年 | 10篇 |
2019年 | 4篇 |
2018年 | 5篇 |
2017年 | 2篇 |
2016年 | 13篇 |
2015年 | 6篇 |
2014年 | 8篇 |
2013年 | 20篇 |
2012年 | 18篇 |
2011年 | 16篇 |
2010年 | 5篇 |
2009年 | 6篇 |
2008年 | 3篇 |
2007年 | 9篇 |
2006年 | 5篇 |
2005年 | 6篇 |
2004年 | 3篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有185条查询结果,搜索用时 15 毫秒
121.
Stefano De Benedetti Valeria Girlando Matias Pasquali Alessio Scarafoni 《Molecules (Basel, Switzerland)》2021,26(16)
Okara is a soybean transformation agri-food by-product, the massive production of which currently poses severe disposal issues. However, its composition is rich in seed storage proteins, which, once extracted, can represent an interesting source of bioactive peptides. Antimicrobial and antifungal proteins and peptides have been described in plant seeds; thus, okara is a valuable source of compounds, exploitable for integrated pest management. The aim of this work is to describe a rapid and economic procedure to isolate proteins from okara, and to produce an enzymatic proteolyzed product, active against fungal plant pathogens. The procedure allowed the isolation and recovery of about 30% of okara total proteins. Several proteolytic enzymes were screened to identify the proper procedure to produce antifungal compounds. Antifungal activity of the protein digested for 24 h with pancreatin against Fusarium and R. solani mycelial growth and Pseudomonas spp was assessed. A dose-response inhibitory activity was established against fungi belonging to the Fusarium genus. The exploitation of okara to produce antifungal bioactive peptides has the potential to turn this by-product into a paradigmatic example of circular economy, since a field-derived food waste is transformed into a source of valuable compounds to be used in field crops protection. 相似文献
122.
M. Woerner C. v. Korff Schmising M. Bargheer N. Zhavoronkov I. Vrejoiu D. Hesse M. Alexe T. Elsaesser 《Applied Physics A: Materials Science & Processing》2009,96(1):83-90
Femtosecond x-ray diffraction provides direct insight into the ultrafast reversible lattice dynamics of materials with a perovskite
structure. Superlattice (SL) structures consisting of a sequence of nanometer-thick layer pairs allow for optically inducing
a tailored stress profile that drives the lattice motions and for limiting the influence of strain propagation on the observed
dynamics. We demonstrate this concept in a series of diffraction experiments with femtosecond time resolution, giving detailed
information on the ultrafast lattice dynamics of ferroelectric and ferromagnetic superlattices. Anharmonically coupled lattice
motions in a SrRuO3/PbZr0.2Ti0.8O3 (SRO/PZT) SL lead to a switch-off of the electric polarizations on a time scale of the order of 1 ps. Ultrafast magnetostriction
of photoexcited SRO layers is demonstrated in a SRO/SrTiO3 (STO) SL. 相似文献
123.
Matias CN Silva AM Santos DA Gobbo LA Schoeller DA Sardinha LB 《Biomedical chromatography : BMC》2012,26(11):1348-1352
Extracellular water (ECW) assessment is based on dilution techniques, commonly using blood sampling. However, plasma collection is an invasive procedure. We aimed to validate the use of saliva for ECW estimation by the bromide dilution technique using plasma as the reference method, in a sample of elite athletes. A total of 89 elite athletes with a mean age of 20.4 ± 4.4 years were evaluated. Baseline samples were collected before sodium bromide oral dose administration, and enriched samples were collected 3 h post‐dose administration. The bromide concentration was assessed by high‐performance liquid chromatography. Comparison of means, concordance coefficient correlation (CCC), multiple regression and Bland–Altman analysis were performed. The ECW from saliva explained 91% of the variance in ECW by plasma with a standard error of estimation of 0.91 kg. The CCC between alternative and reference methods was 0.952. No significant trend was observed between the mean and difference of the methods, with limits of agreement ranging between ?1.5 and 2.1 kg. These findings reveal that bromide dilution volume calculated from saliva samples is a valid noninvasive method for ECW assessment in elite athletes. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
124.
Journal of High Energy Physics - We reformulate classical electromagnetism as the statistical mechanics of lines of electric flux with dynamics described by the string action in four dimensions.... 相似文献
125.
We present a new analysis of Bd,s-->KK modes within the standard model (SM), relating them in a controlled way through SU(3)-flavor symmetry and QCD-improved factorization. We propose a set of sum rules for Bd,s-->K0K0 observables. We determine Bs-->KK branching ratios and CP asymmetries as functions of Adir(Bd-->K0K0), pointing out a conflict between BR(Bs-->K+K-) in the SM and data. Finally, we predict the amount of U-spin breaking between Bd-->pi+pi- and Bs-->K+K-. 相似文献
126.
127.
Over the past few years numerous dual inlet isotope ratio mass spectrometry (IRMS) applications have been adapted to continuous flow systems which allow the automation of sample admission and a higher throughput. The isotopomer analysis of urea nitrogen by IRMS requires the offline conversion of urea into nitrogen gas before analysis. The oxidation of urea with LiOBr results in the monomolecular degradation of urea, which preserves the identity of the parent urea molecule, and has to be conducted under vacuum to prevent contamination with atmospheric nitrogen. We have developed an offline system of urea degradation utilizing disposable Exetainers, in which atmospheric nitrogen is displaced by helium. Recovery of urea nitrogen was linear within the range of the standards tested (0 to 420 microg nitrogen) and standard curves for 15N15N-urea standards showed high coefficients of determination (R2 > 0.9998). A small portion of urea degrades in a non-monomolecular fashion and has been shown to depend on the concentration of urea in the sample. Long-term storage of prepared samples showed a decline in 15N15N enrichment, suggesting air contamination. However, samples were stable for 24 h, which allows for the analysis of large sample batches. Interest in urea metabolism, particularly in ruminant species, has increased recently due to the environmental implications of urea and nitrogen excretion by farm animals. This novel analytical method will allow for accurate measurements and the rapid throughput needed in order to support these field studies. 相似文献
128.
129.
130.
Rafael Conceição Simões Bruno Anderson Matias Rocha Maria Julia Barbosa Bezerra Ito Liberato Barroso‐Neto Francisco Nascimento Pereira‐Junior Raniere da Mata Moura Kyria Santiago do Nascimento Celso Shiniti Nagano Plinio Delatorre Alana de Freitas Pires Ana Maria Sampaio Assreuy Alexandre Holanda Sampaio Benildo Sousa Cavada 《Rapid communications in mass spectrometry : RCM》2012,26(7):811-818