全文获取类型
收费全文 | 151篇 |
免费 | 1篇 |
专业分类
化学 | 76篇 |
晶体学 | 1篇 |
力学 | 4篇 |
数学 | 23篇 |
物理学 | 48篇 |
出版年
2022年 | 2篇 |
2021年 | 8篇 |
2020年 | 2篇 |
2019年 | 3篇 |
2018年 | 6篇 |
2017年 | 2篇 |
2016年 | 10篇 |
2015年 | 1篇 |
2014年 | 7篇 |
2013年 | 7篇 |
2012年 | 5篇 |
2011年 | 15篇 |
2010年 | 6篇 |
2009年 | 6篇 |
2008年 | 4篇 |
2007年 | 4篇 |
2006年 | 11篇 |
2005年 | 5篇 |
2004年 | 1篇 |
2003年 | 1篇 |
2002年 | 2篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 5篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 1篇 |
排序方式: 共有152条查询结果,搜索用时 156 毫秒
1.
N. K. Bakirov 《Journal of Mathematical Sciences》1986,34(1):1403-1413
Let tn be the Bayesian estimator of the parameter constructed from independent observations in the case of infinite information and probability distribution density with some singularities. It is shown that under certain conditions on the behavior of the densities near their singularities, the normalizing factor (n) ensuring that n=(n) (tn-) has a nontriviallimiting distribution for n is regularly varying in Karamata's sense. The limiting distribution of n is determined.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 74, pp. 66–82, 1977.I would like to acknowledge the guidance of I. A. Ibragimov in the course of this research. 相似文献
2.
Genosar L Lasitza T Gepshtein R Leiderman P Koifman N Huppert D 《The journal of physical chemistry. A》2005,109(21):4852-4861
The pressure dependence of the excited-state proton dissociation rate constant of four photoacids, 2-naphthol-6,8-disulfonate (2N68DS), 10-hydroxycamptothecin (10-CPT), 5-cyano-2-naphthol (5CN2), and 5,8-dicyano-2-naphthol (DCN2), are studied in methanol. The results are compared with the results of the pressure dependence study we recently conducted for several photoacids in water, ethanol, and propanol. The pressure dependence is explained using an approximate stepwise two-coordinate proton transfer model. The increase in rate, as a function of pressure, manifests a strong dependence of proton tunneling on the distance which decreases with an increase of pressure between the two oxygen atoms involved in the process. The decrease in the proton transfer rate with increasing pressure reflects the dependence of the reaction on the solvent relaxation rate. We found that, for the relatively weak photoacids 2N68DS, 10-CPT, and 5CN2, the proton transfer rate constant increases by a factor of about 5-8 at a pressure of about 1.5 GPa. For a strong photoacid like DCN2, the rate increase was only by a factor of 2. 相似文献
3.
Amelichev SA Aysin RR Konstantinova LS Obruchnikova NV Rakitin OA Rees CW 《Organic letters》2005,7(25):5725-5727
[chemical reaction: see text]. Treatment of N-substituted 2,5-dimethylpyrroles 2 with an equilibrated mixture of disulfur dichloride and DABCO in chloroform at 0 degrees C gives pentathiepinopyrroles 3 in moderate yields; further reaction of 3 with the same mixture at room temperature leads, in an extensive reaction cascade, to bis(dithiolo)pyrroles 4 in high yield; 2 can be converted into 4 in a one-pot operation under unusually mild conditions. 相似文献
4.
5.
Jakub Čížek Ivan Procházka Radomír Kužel Rinat K. Islamgaliev 《Monatshefte für Chemie / Chemical Monthly》2002,133(6):873-887
Summary. Ultra-fine grained (UFG) Cu (grain size 80 nm) containing 0.5 wt.% Al2O3 nanoparticles (size 20 nm) was prepared by high pressure torsion (HPT). Positron lifetime spectroscopy was employed to characterize
the microstructure of this material, especially with respect to types and concentration of lattice defects. The evolution
of microstructure with increasing temperature was studied by positron lifetime spectroscopy and X-ray diffraction measurements.
The thermal stability of the Cu + 0.5 wt.% Al2O3 nanocomposite was compared with that of pure UFG Cu prepared by the same technique. The processes taking place during thermal
recovery of the initial nanoscale structure in both studied materials are described.
Received October 5, 2001. Accepted (revised) December 20, 2001 相似文献
6.
Owen Zacarias Prof. Ana G. Petrovic Prof. Dr. Rinat Abzalimov Prof. Padmanava Pradhan Prof. Elise Champeil 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(57):14263-14272
Mitomycin C, (MC), an antitumor drug, is a DNA alkylating agent currently used in the clinics. Inert in its native form, MC is reduced to reactive mitosenes, which undergo nucleophilic attack by guanine or adenine bases in DNA to form monoadducts as well as interstrand crosslinks (ICLs). Although ICLs are considered the most cytotoxic lesions, the role of each individual adduct in the drug's cytotoxicity is still not fully understood. Synthetic routes have been developed to access modified oligonucleotides containing dG MC-monoadducts and dG-MC-dG ICL at a single position of their base sequences to investigate the biological effects of these adducts. However, until now, oligonucleotides containing monoadducts formed by MC at the adenine base had not been available, thus preventing the examination of the role played by these lesions in the toxicity of MC. Here, we present a route to access these substrates. Structural proof of the adducted oligonucleotides were provided by enzymatic digestion to nucleosides and high-resolution mass spectral analysis. Additionally, parent oligonucleotides containing a dG monoadduct and a dG-MC-dG ICL were also produced. The stability and physical properties of all substrates were compared via CD spectroscopy and UV melting temperature studies. Finally, virtual models were created to explore the conformational space and structural features of these MC-DNA complexes. 相似文献
7.
8.
Design of pincer complexes based on (methylsulfanyl)acetic/propionic acid amides with ancillary S‐ and N‐donors as potential catalysts and cytotoxic agents
下载免费PDF全文
![点击此处可从《应用有机金属化学》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Svetlana G. Churusova Diana V. Aleksanyan Andrei A. Vasil'ev Ekaterina Yu. Rybalkina Olga Yu. Susova Zinaida S. Klemenkova Rinat R. Aysin Yulia V. Nelyubina Vladimir A. Kozlov 《应用有机金属化学》2018,32(6)
Pincer complexes featuring readily tunable tridentate ligand frameworks comprise one of the most actively studied classes of organometallic and metal–organic compounds and find extensive use in catalysis, organic synthesis, materials science, and other fields of chemistry and allied disciplines. Currently growing attention is devoted to non‐classical ligand scaffolds, such as functionalized carboxamides, which offer multiple options for directed structural modifications. In this study, the reactions of (methylsulfanyl)acetyl and propanoyl chlorides with 2‐(aminomethyl)pyridine, 2‐(2‐aminoethyl)pyridine, 8‐aminoquinoline and 2‐(diphenylthiophosphoryl)aniline afford a series of new pincer‐type ligands based on functionalized carboxamides. The ligands obtained readily undergo direct cyclopalladation under the action of PdCl2(NCPh)2 in dichloromethane at room temperature, resulting in Pd(II) pincer complexes with N,N,S‐ and S,N,S‐donor sets. Importantly, some of the cyclopalladated derivatives can also be produced efficiently under solvent‐free conditions according to the approach recently developed by our group. The complexes obtained have been tested for cytotoxicity against several human cancer cell lines and catalytic activity in the model Suzuki reaction. The results have been compared to those for the related Pd(II) pincer complexes to define the main structure–activity relationships and to outline the most promising structures for further investigations. 相似文献
9.
It is suggested that the interacting boson model be used in the analysis of electron scattering data. Qualitative features of the expected behavior of the inelastic excitation of some 2+ states in the transitional SmNd region are discussed. 相似文献
10.
N. K. Bakirov M. V. Snachev V. E. Bening 《Moscow University Computational Mathematics and Cybernetics》2009,33(1):32-37
An exact formula for the mean number of claims served by a one-channel queuing system (QS) with rejections on a given time interval is obtained, which makes it possible, in particular, to calculate exactly the QS efficiency indexes on an arbitrary time interval. 相似文献