全文获取类型
收费全文 | 860篇 |
免费 | 1篇 |
国内免费 | 4篇 |
专业分类
化学 | 630篇 |
晶体学 | 7篇 |
力学 | 29篇 |
数学 | 91篇 |
物理学 | 108篇 |
出版年
2023年 | 7篇 |
2022年 | 5篇 |
2021年 | 7篇 |
2020年 | 7篇 |
2019年 | 4篇 |
2016年 | 4篇 |
2015年 | 7篇 |
2014年 | 6篇 |
2013年 | 31篇 |
2012年 | 38篇 |
2011年 | 56篇 |
2010年 | 23篇 |
2009年 | 16篇 |
2008年 | 47篇 |
2007年 | 63篇 |
2006年 | 51篇 |
2005年 | 50篇 |
2004年 | 63篇 |
2003年 | 44篇 |
2002年 | 36篇 |
2001年 | 8篇 |
2000年 | 5篇 |
1999年 | 11篇 |
1998年 | 8篇 |
1997年 | 12篇 |
1996年 | 12篇 |
1995年 | 11篇 |
1994年 | 11篇 |
1993年 | 10篇 |
1992年 | 7篇 |
1991年 | 6篇 |
1990年 | 16篇 |
1989年 | 10篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1986年 | 5篇 |
1985年 | 8篇 |
1984年 | 21篇 |
1983年 | 10篇 |
1982年 | 17篇 |
1981年 | 5篇 |
1980年 | 12篇 |
1979年 | 10篇 |
1978年 | 18篇 |
1977年 | 13篇 |
1976年 | 13篇 |
1975年 | 8篇 |
1974年 | 8篇 |
1973年 | 5篇 |
1968年 | 3篇 |
排序方式: 共有865条查询结果,搜索用时 62 毫秒
71.
72.
Sheng Lin Wei Gao Zeru Tian Chao Yang Lihua Lu Jean-Louis Mergny Chung-Hang Leung Dik-Lung Ma 《Chemical science》2015,6(7):4284-4290
A series of luminescent iridium(iii) complexes were synthesised and evaluated for their ability to act as luminescent G-quadruplex-selective probes. The iridium(iii) complex 9 [Ir(pbi)2(5,5-dmbpy)]PF6 (where pbi = 2-phenyl-1H-benzo[d]imidazole; 5,5-dmbpy = 5,5′-dimethyl-2,2′-bipyridine) exhibited high luminescence for G-quadruplex DNA compared to dsDNA and ssDNA, and was employed to construct a G-quadruplex-based assay for protein tyrosine kinase-7 (PTK7) in aqueous solution. PTK7 is an important biomarker for a range of leukemias and solid tumors. In the presence of PTK7, the specific binding of the sgc8 aptamer sequence triggers a structural transition and releases the G-quadruplex-forming sequence. The formation of the nascent G-quadruplex structure is then detected by the G-quadruplex-selective iridium(iii) complex with an enhanced luminescent response. Moreover, the application of the assay for detecting PTK7 in cellular debris and membrane protein extract was demonstrated. To our knowledge, this is the first G-quadruplex-based assay for PTK7. 相似文献
73.
74.
75.
76.
James D. Oliver Adam A. Rosser Christopher M. Fellows Yohann Guillaneuf Jean-Louis Clement Marianne Gaborieau Patrice Castignolles 《Analytica chimica acta》2014
Direct UV detection of carbohydrates in free solution capillary electrophoresis at 270 nm is made possible by a photo-oxidation reaction. Glucose, rhamnose and xylose were shown to have unique UV absorption spectra hypothesizing different UV absorbing intermediates for their respective photo-oxidation. NMR spectroscopy of the photo-oxidation end products proved they consisted of carboxylates and not malondialdehyde as previously theorized and that oxygen thus plays a key role in the photo-oxidation pathway. Adding the photo-initiator Irgacure® 2959 in the background electrolyte increased sensitivity by 40% at an optimum concentration of 1 × 10−4 mM and 1 × 10−8 mM for conventional 50 μm i.d. capillaries and for the corresponding extended light path capillaries, respectively. 相似文献
77.
78.
Water-dispersible sugar-coated iron oxide nanoparticles. An evaluation of their relaxometric and magnetic hyperthermia properties 总被引:1,自引:0,他引:1
Lartigue L Innocenti C Kalaivani T Awwad A Sanchez Duque Mdel M Guari Y Larionova J Guérin C Montero JL Barragan-Montero V Arosio P Lascialfari A Gatteschi D Sangregorio C 《Journal of the American Chemical Society》2011,133(27):10459-10472
Synthesis of functionalized magnetic nanoparticles (NPs) for biomedical applications represents a current challenge. In this paper we present the synthesis and characterization of water-dispersible sugar-coated iron oxide NPs specifically designed as magnetic fluid hyperthermia heat mediators and negative contrast agents for magnetic resonance imaging. In particular, the influence of the inorganic core size was investigated. To this end, iron oxide NPs with average size in the range of 4-35 nm were prepared by thermal decomposition of molecular precursors and then coated with organic ligands bearing a phosphonate group on one side and rhamnose, mannose, or ribose moieties on the other side. In this way a strong anchorage of the organic ligand on the inorganic surface was simply realized by ligand exchange, due to covalent bonding between the Fe(3+) atom and the phosphonate group. These synthesized nanoobjects can be fully dispersed in water forming colloids that are stable over very long periods. Mannose, ribose, and rhamnose were chosen to test the versatility of the method and also because these carbohydrates, in particular rhamnose, which is a substrate of skin lectin, confer targeting properties to the nanosystems. The magnetic, hyperthermal, and relaxometric properties of all the synthesized samples were investigated. Iron oxide NPs of ca. 16-18 nm were found to represent an efficient bifunctional targeting system for theranostic applications, as they have very good transverse relaxivity (three times larger than the best currently available commercial products) and large heat release upon application of radio frequency (RF) electromagnetic radiation with amplitude and frequency close to the human tolerance limit. The results have been rationalized on the basis of the magnetic properties of the investigated samples. 相似文献
79.
Smith NM Labrunie G Corry B Tran PL Norret M Djavaheri-Mergny M Raston CL Mergny JL 《Organic & biomolecular chemistry》2011,9(17):6154-6162
A series of novel 2,4,6-triarylpyridines have been synthesized and their interactions with intramolecular G-quadruplexes have been measured by F?rster Resonance Energy Transfer (FRET) melting and Fluorescent Intercalator Displacement (FID) assays. A few of these compounds exhibit stabilization of G4-DNA that is comparable to other benchmark G4-DNA ligands with fair to excellent G4-DNA vs. duplex selectivity and significant cytotoxicity towards HeLa cells. The nature of the 4-aryl substituents along with side chain length governs the G4-DNA stabilization ability of the compounds. In addition, we demonstrate that there is a strong correlation between the ability of the compounds to stabilize the same G4-DNA sequence in K(+) and Na(+) conditions and a strong correlation between the ability of the compounds to stabilize different G4-DNA sequences in K(+) or Na(+) buffer. 相似文献
80.
Okadaic acid (OA), responsible for gastrointestinal problems, inhibits protein phosphatase 2A (PP2A). Therefore, the inhibition exerted by the toxin on PP2A could be used to detect the presence of OA in aqueous solution and in shellfish sample.In this work, two commercial PP2As (from ZEU Immunotec and Millipore) and one produced by molecular engineering (from GTP Technology) were tested. Enzymes were used in solution and also immobilized within a polymeric gel. In solution, best performances were obtained using PP2A purchased from ZEU Immunotec (Spain). OA was detected in aqueous solution in concentration as low as 0.0124 μg L−1 using the enzyme from ZEU Immunotec whereas the detection limits were 0.47 μg L−1 and 0.123 μg L−1 with PP2As from Millipore and GTP Technology, respectively. Considering that the immobilization step contributes to stabilize the PP2A activity, enzymes were entrapped within a photopolymer and an agarose gel. These different polymeric matrices were optimized, tested and compared. Agarose gel seems to be a good alternative to the photopolymer largely used in our group. For instance, the IC50 value obtained with the test based on PP2A from ZEU Immunotec immobilized within an agarose gel was 1.98 μg L−1. This value was 1.8-fold lower than those obtained with the photopolymer test using the same enzyme. The proposed test is sensitive, fast and does not require expensive equipment. To evaluate the efficiency of the assay, PP inhibition tests based on PP2A from ZEU Immunotec in solution or immobilized within a gel were used for OA detection in contaminated shellfish. 相似文献