全文获取类型
收费全文 | 1239篇 |
免费 | 1篇 |
国内免费 | 7篇 |
专业分类
化学 | 998篇 |
晶体学 | 7篇 |
力学 | 33篇 |
数学 | 98篇 |
物理学 | 111篇 |
出版年
2023年 | 6篇 |
2022年 | 10篇 |
2021年 | 8篇 |
2019年 | 6篇 |
2018年 | 5篇 |
2016年 | 6篇 |
2014年 | 7篇 |
2013年 | 51篇 |
2012年 | 49篇 |
2011年 | 54篇 |
2010年 | 34篇 |
2009年 | 26篇 |
2008年 | 86篇 |
2007年 | 71篇 |
2006年 | 77篇 |
2005年 | 77篇 |
2004年 | 79篇 |
2003年 | 71篇 |
2002年 | 41篇 |
2001年 | 12篇 |
2000年 | 7篇 |
1999年 | 14篇 |
1998年 | 13篇 |
1997年 | 13篇 |
1996年 | 17篇 |
1995年 | 12篇 |
1994年 | 17篇 |
1993年 | 19篇 |
1992年 | 15篇 |
1991年 | 9篇 |
1990年 | 12篇 |
1989年 | 8篇 |
1988年 | 7篇 |
1987年 | 11篇 |
1986年 | 6篇 |
1985年 | 36篇 |
1984年 | 24篇 |
1983年 | 17篇 |
1982年 | 27篇 |
1981年 | 14篇 |
1980年 | 29篇 |
1979年 | 15篇 |
1978年 | 22篇 |
1977年 | 13篇 |
1976年 | 17篇 |
1975年 | 18篇 |
1974年 | 21篇 |
1973年 | 14篇 |
1971年 | 4篇 |
1969年 | 4篇 |
排序方式: 共有1247条查询结果,搜索用时 15 毫秒
991.
In this paper we show the well-posedness and stability of the Maxwell scattering problem with the transparent boundary condition. The proof depends on the well-posedness of the time-harmonic Maxwell scattering problem with complex wave numbers which is also established. 相似文献
992.
Katia Bacha Catherine Chemotti Jean-Claude Monboisse Anthony Robert Aurlien L. Furlan Willy Smeralda Christian Damblon Julien Estager Sylvie Brassart-Pasco Jean-Pierre Mbakidi Jelena Pri Sandrine Bouquillon Magali Deleu 《Molecules (Basel, Switzerland)》2022,27(22)
Vitamin C is one of the most sensitive cosmetic active ingredients. To avoid its degradation, its encapsulation into biobased carriers such as dendrimers is one alternative of interest. In this work, we wanted to evaluate the potential of two biobased glycerodendrimer families (GlyceroDendrimers-Poly(AmidoAmine) (GD-PAMAMs) or GlyceroDendrimers-Poly(Propylene Imine) (GD-PPIs)) as a vitamin C carrier for topical application. The higher encapsulation capacity of GD-PAMAM-3 compared to commercial PAMAM-3 and different GD-PPIs, and its absence of cytotoxicity towards dermal cells, make it a good candidate. Investigation of its mechanism of action was done by using two kinds of biomimetic models of stratum corneum (SC), lipid monolayers and liposomes. GD-PAMAM-3 and VitC@GD-PAMAM-3 (GD-PAMAM-3 with encapsulated vitamin C) can both interact with the lipid representatives of the SC lipid matrix, whichever pH is considered. However, only pH 5.0 is suggested to be favorable to release vitamin C into the SC matrix. Their binding to SC-biomimetic liposomes revealed only a slight effect on membrane permeability in accordance with the absence of cytotoxicity but an increase in membrane rigidity, suggesting a reinforcement of the SC barrier property. Globally, our results suggest that the dendrimer GD-PAMAM-3 could be an efficient carrier for cosmetic applications. 相似文献
993.
Luo Junhua Liang Xinghua Zhang Yuhao Liang Chenghua Yassine Hassan Leroy Gérard Carru Jean-Claude Mascot Manuel 《Journal of Solid State Electrochemistry》2021,25(8-9):2225-2233
Journal of Solid State Electrochemistry - In lithium battery research, when we need to establish equivalent circuit based on impedance measurement, we can find several suitable circuit models. We... 相似文献
994.
We derive quantitative bounds for eigenvalues of complex perturbations of the indefinite Laplacian on the real line. Our results substantially improve existing results even for real potentials. For -potentials, we obtain optimal spectral enclosures which accommodate also embedded eigenvalues, while our result for -potentials yield sharp spectral bounds on the imaginary parts of eigenvalues of the perturbed operator for all . The sharpness of the results are demonstrated by means of explicit examples. 相似文献
995.
Aurélien Adenot Dr. Niklas von Wolff Dr. Guillaume Lefèvre Dr. Jean-Claude Berthet Dr. Pierre Thuéry Dr. Thibault Cantat 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(34):8118-8126
The guanidine 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) and the substituted derivatives [TBD–SiR2]+ and TBD–BR2 reacted with SO2 to give different FLP–SO2 adducts. Molecular structures, elucidated by X-ray diffraction, showed some structural similarities with the analogous CO2 adducts. Thermodynamic stabilities were both experimentally evidenced and computed through DFT calculations. The underlying parameters governing the relative stabilities of the different SO2 and CO2 adducts were discussed from a theoretical standpoint, with a focus on the influence of the Lewis acidic moiety. 相似文献
996.
Jean-Claude Alvarez Isabelle Etting Islam Amine Larabi 《Biomedical chromatography : BMC》2022,36(8):e5391
An LC-MS/MS method for hair testing of glyphosate and aminomethylphosphonic acid (AMPA), its main biodegradation product, has been developed. After decontamination, 50 mg of hair was ground and sonicated in water for 2 h. The method was fully validated in the 5–500 pg/mg range for glyphosate and 10–500 pg/mg for AMPA, and the limits of detection were 2 and 5 pg/mg, respectively. Matrix effect for glyphosate and AMPA was compensated by an isotope-labeled internal standard. Hair samples from four farmers who regularly used glyphosate and one farmer who used glyphosate but not his wife and 14 hair samples from nonoccupationally exposed subjects were tested. Glyphosate was found in head hair of three farmers, with concentration in the range 14–188 pg/mg. The fourth was found negative but with hair colored in red. Glyphosate was detected in 10 of 14 hair samples from nonoccupationally exposed subjects at concentrations of 11.5 pg/mg or lower and only in one segment (0–3 cm) of the farmer's spouse (6 pg/mg). AMPA was detected in five subjects, above the limit of quantification only in two of three occupationally exposed subjects with positive glyphosate. Further studies should be conducted to validate this potential new biomarker that could be useful for assessing long-term exposure to glyphosate. 相似文献
997.
Aequationes mathematicae - The meaningfulness condition, applied to scientific or geometric laws, requires that the mathematical form of an equation does not change when we change the units of its... 相似文献
998.
999.
1000.