全文获取类型
收费全文 | 310篇 |
免费 | 14篇 |
国内免费 | 2篇 |
专业分类
化学 | 190篇 |
晶体学 | 1篇 |
力学 | 5篇 |
数学 | 74篇 |
物理学 | 56篇 |
出版年
2023年 | 3篇 |
2022年 | 3篇 |
2019年 | 8篇 |
2018年 | 4篇 |
2017年 | 2篇 |
2016年 | 10篇 |
2015年 | 10篇 |
2014年 | 8篇 |
2013年 | 3篇 |
2012年 | 16篇 |
2011年 | 22篇 |
2010年 | 5篇 |
2009年 | 12篇 |
2008年 | 15篇 |
2007年 | 18篇 |
2006年 | 15篇 |
2005年 | 19篇 |
2004年 | 15篇 |
2003年 | 14篇 |
2002年 | 15篇 |
2001年 | 12篇 |
2000年 | 6篇 |
1999年 | 7篇 |
1998年 | 3篇 |
1997年 | 7篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1993年 | 7篇 |
1992年 | 5篇 |
1991年 | 5篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 5篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1978年 | 7篇 |
1976年 | 1篇 |
1975年 | 4篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1971年 | 2篇 |
1970年 | 1篇 |
1940年 | 1篇 |
1935年 | 1篇 |
排序方式: 共有326条查询结果,搜索用时 13 毫秒
231.
Babu BR Hrdlicka PJ McKenzie CJ Wengel J 《Chemical communications (Cambridge, England)》2005,(13):1705-1707
Incorporation of N,N-bis(2-pyridylmethyl)-beta-alanyl 2'-amino-LNA (bipyridyl-functionalized 2'-amino locked nucleic acid) monomers into DNA strands enables high-affinity targeting of complementary DNA with excellent Watson-Crick selectivity in the presence of divalent metal ions. Positioning of bipyridyl-functionalized 2'-amino-LNA monomers in two complementary DNA strands in a "3'-end zipper" constitution allows modulation of duplex stability, i.e., a strong stabilizing effect with one equivalent of divalent metal ion per bipyridyl pair, or a strong destabilizing effect with an excess of divalent metal ions. 相似文献
232.
W. M. McKenzie D. C. Sherrington 《Journal of polymer science. Part A, Polymer chemistry》1982,20(2):431-441
Two groups of phosphine-containing resins were prepared by bead copolymerization. In one the phosphine residues were introduced as pendant groups with p-styryldiphenylphosphine, whereas in the other the phosphine residues were located specifically at crosslinked points with bis(p-styryl)phenylphosphine. Both groups of resins were used to convert alcohols to alkyl chlorides in the presence of carbon tetrachloride and benzaldyhyde to benzal chloride and β,β-dichlorostyrene. In the first reaction an increase in the crosslink ratio of the support reduced the reactivity of the resins, although both octanol and octadecanol substrates behaved similarly. No clear difference emerged between resins with pendant phosphine groups and those located on crosslinks and the absence of a strong substrate size effect or substrate selectivity with both series of resins was apparent. The production of benzal chloride and β,β-dichlorostyrene requires interaction of two phosphine residues to generate the reactive intermediate, and inhibition of phosphine–phosphine interactions in these highly crosslinked networks does indeed inhibit this reaction. Again both series of resins behaved similarly. Among the possible routes by which PPh3/CCl4 converts alcohols to chlorides one involving phosphine-phosphine interactions must also be inhibited in these supported systems. 相似文献
233.
234.
Allin SM Gaskell SN Towler JM Page PC Saha B McKenzie MJ Martin WP 《The Journal of organic chemistry》2007,72(23):8972-8975
We report a novel, facile, and asymmetric approach for the synthesis of the anti-tumor alkaloid (+)-crispine A via a highly diastereoselective N-acyliminium cyclization reaction as a key synthetic step. 相似文献
235.
Alex Gibney Dr. Raphael E. F. de Paiva Dr. Vandana Singh Robert Fox Prof. Dr. Damien Thompson Dr. Joseph Hennessy Dr. Creina Slator Prof. Dr. Christine J. McKenzie Dr. Pegah Johansson Prof. Dr. Vickie McKee Prof. Dr. Fredrik Westerlund Prof. Dr. Andrew Kellett 《Angewandte Chemie (International ed. in English)》2023,62(38):e202305759
Artificial metallo-nucleases (AMNs) are promising DNA damaging drug candidates. Here, we demonstrate how the 1,2,3-triazole linker produced by the Cu-catalysed azide-alkyne cycloaddition (CuAAC) reaction can be directed to build Cu-binding AMN scaffolds. We selected biologically inert reaction partners tris(azidomethyl)mesitylene and ethynyl-thiophene to develop TC-Thio, a bioactive C3-symmetric ligand in which three thiophene-triazole moieties are positioned around a central mesitylene core. The ligand was characterised by X-ray crystallography and forms multinuclear CuII and CuI complexes identified by mass spectrometry and rationalised by density functional theory (DFT). Upon Cu coordination, CuII-TC-Thio becomes a potent DNA binding and cleaving agent. Mechanistic studies reveal DNA recognition occurs exclusively at the minor groove with subsequent oxidative damage promoted through a superoxide- and peroxide-dependent pathway. Single molecule imaging of DNA isolated from peripheral blood mononuclear cells shows that the complex has comparable activity to the clinical drug temozolomide, causing DNA damage that is recognised by a combination of base excision repair (BER) enzymes. 相似文献
236.
Maltsev families of varieties which are closed under join or Maltsev product are investigated. New Maltsev conditions for congruence semi-distributivity are given. 相似文献
237.
The rate of hybridization of oligonucleotide target sequences to chemically immobilized oligonucleotide probes has been studied both with and without an electrical field. The probe size was 20-24 nucleotides (nt) while the target size ranged from 157 to 864 nt. In agreement with previous studies, complete hybridization under normal conditions required 10-30 hours, depending on target size. The kinetics were characterized by a characteristic lag time followed by an asymptotic rise to the final value. In contrast, with an applied electrical field, all but the largest target hybridized in about 10 min while the longest hybridized within 1 h. Deleterious electrode reactions were avoided by close spacing of the anode and cathode and application of very small voltages. Our results suggest that probes and targets orient flat on the surface. A model is suggested to explain the kinetics observed that involves a series of surface states between initial target arrival and final hybridized state. Our results show that the electric field accelerated hybrid capture of solution-phase targets by surface-bound probes. This approach may have implications for enhancing array-based hybrid capture for mutation detection, copy number determination and/or gene expression profiling. 相似文献
238.
Ramnial T Abernethy CD Spicer MD McKenzie ID Gay ID Clyburne JA 《Inorganic chemistry》2003,42(5):1391-1393
The structure of 1,3-bis(2,4,6-trimethylphenyl)-imidazol-2-ylidene-silver(I) chloride, 1, has been determined to be a monomer with weak head-to-tail H...Cl interactions in the solid state. A multinuclear NMR study using a (13)C(carbene) labeled derivative, 1((13)C), exhibits (13)C-(107,109)Ag coupling in solution. Further, the solid state CP/MAS NMR parameters, including the principal components of the chemical shift tensors for both the (13)C and (109)Ag centers, have been determined. With the aid of DFT calculations, the orientation of the chemical shift tensors have been assigned. 相似文献
239.
Seckmeyer G Klingebiel M Riechelmann S Lohse I McKenzie RL Liley JB Allen MW Siani AM Casale GR 《Photochemistry and photobiology》2012,88(1):215-222
Doses of erythemally weighted irradiances derived from polysulphone (PS) and electronic ultraviolet (EUV) dosimeters have been compared with measurements obtained using a reference spectroradiometer. PS dosimeters showed mean absolute deviations of 26% with a maximum deviation of 44%, the calibrated EUV dosimeters showed mean absolute deviations of 15% (maximum 33%) around noon during several test days in the northern hemisphere autumn. In the case of EUV dosimeters, measurements with various cut-off filters showed that part of the deviation from the CIE erythema action spectrum was due to a small, but significant sensitivity to visible radiation that varies between devices and which may be avoided by careful preselection. Usually the method of calibrating UV sensors by direct comparison to a reference instrument leads to reliable results. However, in some circumstances the quality of measurements made with simple sensors may be over-estimated. In the extreme case, a simple pyranometer can be used as a UV instrument, providing acceptable results for cloudless skies, but very poor results under cloudy conditions. It is concluded that while UV dosimeters are useful for their design purpose, namely to estimate personal UV exposures, they should not be regarded as an inexpensive replacement for meteorological grade instruments. 相似文献
240.
Serum Albumin Binding Inhibits Nuclear Uptake of Luminescent Metal‐Complex‐Based DNA Imaging Probes 下载免费PDF全文
Dr. Ashley Wragg Dr. Martin R. Gill Luke McKenzie Caroline Glover Rachel Mowll Dr. Julia A. Weinstein Dr. Xiaodi Su Prof. Carl Smythe Prof. Jim A. Thomas 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(33):11865-11871
The DNA binding and cellular localization properties of a new luminescent heterobimetallic IrIIIRuII tetrapyridophenazine complex are reported. Surprisingly, in standard cell media, in which its tetracationic, isostructural RuIIRuII analogue is localized in the nucleus, the new tricationic complex is poorly taken up by live cells and demonstrates no nuclear staining. Consequent cell‐free studies reveal that the IrIIIRuII complex binds bovine serum albumin, BSA, in Sudlow’s Site I with a similar increase in emission and binding affinity to that observed with DNA. Contrastingly, in serum‐free conditions the complex is rapidly internalized by live cells, where it localizes in cell nuclei and functions as a DNA imaging agent. The absence of serum proteins also greatly alters the cytotoxicity of the complex, where high levels of oncosis/necrosis are observed due to this enhanced uptake. This suggests that simply increasing the lipophilicity of a DNA imaging probe to enhance cellular uptake can be counterproductive as, due to increased binding to serum albumin protein, this strategy can actually disrupt nuclear targeting. 相似文献