全文获取类型
收费全文 | 1088篇 |
免费 | 38篇 |
国内免费 | 9篇 |
专业分类
化学 | 709篇 |
晶体学 | 30篇 |
力学 | 21篇 |
数学 | 162篇 |
物理学 | 213篇 |
出版年
2023年 | 5篇 |
2022年 | 41篇 |
2021年 | 52篇 |
2020年 | 24篇 |
2019年 | 27篇 |
2018年 | 31篇 |
2017年 | 33篇 |
2016年 | 47篇 |
2015年 | 23篇 |
2014年 | 54篇 |
2013年 | 63篇 |
2012年 | 80篇 |
2011年 | 81篇 |
2010年 | 56篇 |
2009年 | 46篇 |
2008年 | 60篇 |
2007年 | 60篇 |
2006年 | 55篇 |
2005年 | 55篇 |
2004年 | 48篇 |
2003年 | 29篇 |
2002年 | 19篇 |
2001年 | 13篇 |
2000年 | 11篇 |
1999年 | 9篇 |
1998年 | 5篇 |
1997年 | 7篇 |
1996年 | 6篇 |
1995年 | 8篇 |
1994年 | 6篇 |
1993年 | 8篇 |
1992年 | 5篇 |
1991年 | 8篇 |
1990年 | 10篇 |
1989年 | 1篇 |
1988年 | 6篇 |
1987年 | 1篇 |
1986年 | 6篇 |
1985年 | 4篇 |
1984年 | 11篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1973年 | 2篇 |
1970年 | 1篇 |
排序方式: 共有1135条查询结果,搜索用时 31 毫秒
71.
Jakub Trawiski Micha Wroski Maciej Gawlik Robert Skibiski 《Molecules (Basel, Switzerland)》2022,27(3)
In this study, the phase I hepatic metabolism pathway of a cardiovascular drug nebivolol was proposed on the basis of a human liver microsomes assay with the use of LC-HR-MS coupled with the chemometric method. Six biotransformation products were found with the assistance of chemometric analysis. Five of them were identified as the previously reported products of alicyclic hydroxylation and dihydroxylation, aromatic hydroxylation, as well as alicyclic oxidation of the parent compound. Moreover, one metabolite, not reported so far, was found to be a product of N-dealkylation of nebivolol—2-amino-1-(6-fluoro-3,4-dihydro-2H-1-benzopyran-2-yl)ethan-1-ol. The novel metabolite was submitted to an in silico toxicity analysis to assess its biological properties. The applied computational methods indicated a significantly elevated risk of its mutagenic activity, compared to the parent molecule. Several metabolites of the nebivolol described in the literature were not detected in this study, indicating their non-hepatic origin. 相似文献
72.
Ang Han Wei Chan Aik Hui Ghaffar Mahumm Rybczyński Maciej Wilk Grzegorz Włodarczyk Zbigniew 《The European Physical Journal A - Hadrons and Nuclei》2020,56(4):1-8
The European Physical Journal A - The transverse momentum ($$p_{T}$$) distribution of strange hadrons ($$K_{S}^{0}$$ and $$\varLambda $$) and multi-strange hadrons( $$\varXi $$ and $$\varOmega $$)... 相似文献
73.
Guanidinoamidized linear polyethyleneimine for gene delivery 总被引:1,自引:0,他引:1
Guanidine was introduced to low molecular weight linear polyethyleneimine(LPEI) via amide groups, to explore the effect of both guanidine degree and pendant chain length on its transfection behavior. The resulting guanidinoamidized LPEIs(GLPEIs) could dramatically reduce LPEI's toxicity, enhance its DNA-packaging capability, cellular uptake and therefore transfection efficiency. These polyplexes were taken up very efficiently via caveolae-mediated endocytosis and their transfection efficiencies in ovarian cancer cells were significantly improved compared to native LPEI10 k polyplexes. Among these GLPEIs, LPEI-C3-G100 showed higher DNA affinity even than LPEI25 k and the highest transfection efficiency, probably due to the optimization of polymer chain flexibility. Of notice, LPEI-C3-G100 polyplexes could more effectively accumulate into cytoplasm than LPEI25 k, although the transfection efficiency of LPEI-C3-G100 polyplexes was not superior to that of LPEI25 k polyplexes, which would be probably attributed to the more efficient release of LPEI25 k polyplexes than LPEI-C3-G100 polyplexes in the cytoplasm. 相似文献
74.
Ireneusz Sowa Magdalena Wójciak-Kosior Piotr Drączkowski Maciej Strzemski Ryszard Kocjan 《Analytica chimica acta》2013
The new sorbent for non-suppressed ion chromatography based on silica gel coated with a film of polyaniline (PANI) was obtained in a process of in situ polymerization of aniline by oxidation with ammonium peroxydisulfate. Raman analyses performed using a Thermo Scientific DXR confocal Raman Microscope equipped with the Omnic 8 software from Thermo Fisher Scientific have proved a uniform distribution of PANI on the surface of chromatographic beads and in the pores of the particle. 相似文献
75.
Hieronim Maciejewski Agnieszka Sydor Maciej Kubicki 《Journal of organometallic chemistry》2004,689(19):3075-3081
Reactions of the nickel(0) complexes [Ni(cod)2] (in the presence of PP or [Ni(PPh3)2C2H4] with vinyl-siloxanes, -silanes or -silazanes yield, by displacement of alkene ligand, the new nickel π-complexes [Ni(PPh3)2(η-CH2CHSi(OSiMe3)3)] (2), [{Ni(PPh3)}2{μ-(η-{(CH2CH)2SiMe}2O})] (4), [Ni(PPh3){η4-CH2CHSi(Me)(μ-O)}3] (5), [{Ni(η-CH2CHSiMe2)2O}(η-CH2CHSiMe3)] (7) and the known complexes [Ni(PPh3)2(η-CH2CHSiMe3)] (1), [{Ni(PPh3)}2{μ-(η-(CH2CH)4Si})] (3), [{Ni(PPh3)(η-CH2CHSiMe2)2NH}] (6) obtained by a simple one pot synthesis, more efficiently than in hitherto published reports. The X-ray crystal structure of (1) shows a trigonal planar environment around the nickel atom. 相似文献
76.
Constitutive laws are presented for the inelastic analysis of laminated composite plates. The implications of using an elastoplastic theory, applied in a stress-resultant formulation, are discussed and investigated. Two different stress-resultant plasticity theories are proposed, both of which overlook the matrix and fiber inelastic behavior and describe the inelastic response of the laminate as a function of overall laminate properties. Results from numerical experiments with the proposed models are compared with results obtained using a micromechanical elastoplastic composite constitutive model. 相似文献
77.
78.
We consider homomorphisms from a normed space into a topological group. Assuming their boundedness in a neighbourhood (in relative topology) of an extremal point of the unit sphere, we derive their linearity (whenever it makes sense), closedness of the graph or continuity. 相似文献
79.
80.
We prove some inequalities for the difference between a joint distribution and the product of its marginals for arbitrary
absolutely continuous random variables. Some applications of the obtained inequalities are also presented. 相似文献