全文获取类型
收费全文 | 365篇 |
免费 | 8篇 |
国内免费 | 1篇 |
专业分类
化学 | 258篇 |
晶体学 | 11篇 |
力学 | 4篇 |
数学 | 15篇 |
物理学 | 86篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 3篇 |
2020年 | 4篇 |
2019年 | 12篇 |
2018年 | 3篇 |
2017年 | 5篇 |
2016年 | 4篇 |
2015年 | 8篇 |
2014年 | 9篇 |
2013年 | 12篇 |
2012年 | 33篇 |
2011年 | 20篇 |
2010年 | 12篇 |
2009年 | 12篇 |
2008年 | 23篇 |
2007年 | 17篇 |
2006年 | 12篇 |
2005年 | 17篇 |
2004年 | 17篇 |
2003年 | 10篇 |
2002年 | 11篇 |
2001年 | 7篇 |
2000年 | 11篇 |
1999年 | 9篇 |
1998年 | 3篇 |
1997年 | 8篇 |
1996年 | 7篇 |
1995年 | 6篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 10篇 |
1991年 | 4篇 |
1990年 | 8篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1986年 | 5篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 4篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1978年 | 6篇 |
1977年 | 1篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1970年 | 1篇 |
1929年 | 1篇 |
排序方式: 共有374条查询结果,搜索用时 46 毫秒
31.
A Matsuyama 《Radioisotopes》1990,39(7):316-325
32.
Keigo Kobayashi Prof. Hirokazu Kobayashi Prof. Mitsuhiko Maesato Dr. Mikihiro Hayashi Tomokazu Yamamoto Dr. Satoru Yoshioka Prof. Syo Matsumura Prof. Takeharu Sugiyama Dr. Shogo Kawaguchi Prof. Yoshiki Kubota Prof. Hiroshi Nakanishi Prof. Hiroshi Kitagawa 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(23):6678-6682
We report on hexagonal close-packed (hcp) palladium (Pd)–boron (B) nanocrystals (NCs) by heavy B doping into face-centered cubic (fcc) Pd NCs. Scanning transmission electron microscopy–electron energy loss spectroscopy and synchrotron powder X-ray diffraction measurements demonstrated that the B atoms are homogeneously distributed inside the hcp Pd lattice. The large paramagnetic susceptibility of Pd is significantly suppressed in Pd–B NCs in good agreement with the reduction of density of states at Fermi energy suggested by X-ray absorption near-edge structure and theoretical calculations. 相似文献
33.
Toshinori Taishi Hideaki Ise Yu Murao Takayuki Osawa Masashi Suezawa Yuki Tokumoto Yutaka Ohno Keigo Hoshikawa Ichiro Yonenaga 《Journal of Crystal Growth》2010,312(19):2783-2787
Oxygen-containing germanium (Ge) single crystals with low density of grown-in dislocations were grown by the Czochralski (CZ) technique from a Ge melt, both with and without a covering by boron oxide (B2O3) liquid. Interstitially dissolved oxygen concentrations in the crystals were determined by the absorption peak at 855 cm−1 in the infrared absorption spectra at room temperature. It was found that oxygen concentration in a Ge crystal grown from melt partially or fully covered with B2O3 liquid was about 1016 cm−3 and was almost the same as that in a Ge crystal grown without B2O3. Oxygen concentration in a Ge crystal was enhanced to be greater than 1017 cm−3 by growing a crystal from a melt fully covered with B2O3; with the addition of germanium oxide powder, the maximum oxygen concentration achieved was 5.5×1017 cm−3. The effective segregation coefficients of oxygen in the present Ge crystal growth were roughly estimated to be between 1.0 and 1.4. 相似文献
34.
Chiral Ammonium Betaine‐Catalyzed Highly Stereoselective Aza‐Henry Reaction of α‐Aryl Nitromethanes with Aromatic N‐Boc Imines
下载免费PDF全文
![点击此处可从《化学:亚洲杂志》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Daisuke Uraguchi Keigo Oyaizu Haruhiro Noguchi Prof. Dr. Takashi Ooi 《化学:亚洲杂志》2015,10(2):334-337
A highly stereoselective aza‐Henry reaction of α‐aryl nitromethanes with aromatic N‐Boc imines was established by using C1‐symmetric chiral ammonium betaine as a bifunctional organic base catalyst. Various substituted aryl groups for both imines and nitromethanes were tolerated in the reaction, and a series of precursors for the synthesis of unsymmetrical anti‐1,2‐diaryl ethylenediamines was provided. 相似文献
35.
Otani M Taniguchi T Sakai A Seta J Kadoyama K Nakamura-Hirota T Matsuyama S Sano K Takano M 《Applied biochemistry and biotechnology》2011,164(6):804-818
We validated the novel PhosphoQUANTI SolidBlue Complex (PQSC) dye for the sensitive fluorescent detection of phosphorylated proteins in polyacrylamide- and two-dimensional gel electrophoresis (PAGE and 2DE, respectively). PQSC can detect as little as 15.6 ng of ß-casein, a pentaphosphorylated protein, and 61.3 ng of ovalbumin, a diphosphorylated protein. Fluorescence intensity correlates with the number of phosphorylated residues on the protein. To demonstrate the specificity of PQSC for phosphoproteins, enzymatically dephosphorylated lysates of Swiss 3T3 cells were separated in 2DE gels and stained by PQSC. The fluorescence signals in these gels were markedly reduced following dephosphorylation. When the phosphorylated proteins in Swiss 3T3 cell lysates were concentrated using a phosphoprotein enrichment column, the majority of phosphoproteins showed fluorescence signals in the pI 4–5 range. Finally, we performed phosphoproteome analysis to study differences in the protein phosphorylation profiles of proliferating and quiescent Swiss 3T3 cells. Over 135 discernible protein spots were detected, from which a selection of 15 spots were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF-MS). The PQSC staining procedure for phosphoprotein detection is simple, reversible, and fully compatible with MALDI TOF-MS. 相似文献
36.
This review article summarizes our recent researches for molecular design of polyoxometalates (POMs) and their related compounds
for environmentally-friendly functional group transformations. The divacant POM [γ-SiW10O34(H2O)2]4− exhibits high catalytic performance for mono-oxygenation-type reactions including epoxidation of olefins and allylic alcohols,
sulfoxidation, and hydroxylation of organosilanes with H2O2. We have successfully synthesized several POM-based molecular catalysts (metal-substituted POMs) with controlled active sites
by the introduction of metal species into the divacant POM as a “structural motif”. These molecular catalysts can efficiently
activate H2O2 (vanadium-substituted POM for epoxidation) and alkynes (copper-substituted POM for click reaction and oxidative homocoupling
of alkynes). The aluminum-substituted POM exhibits Lewis acidic catalysis for diastereoselective cyclization of (+)-citronellal
to (−)-isopulegol. In addition, we have developed POM-based “molecular heterogeneous catalysts” by the “solidification” and
“immobilization” of catalytically active POMs. 相似文献
37.
Takaoka Y Kiminami K Mizusawa K Matsuo K Narazaki M Matsuda T Hamachi I 《Journal of the American Chemical Society》2011,133(30):11725-11731
(19)F NMR/MRI probe is expected to be a powerful tool for selective sensing of biologically active agents owing to its high sensitivity and no background signals in live bodies. We have recently reported a unique supramolecular strategy for specific protein detection using a protein ligand-tethered self-assembling (19)F probe. This method is based on a recognition-driven disassembly of the nanoprobes, which induced a clear turn-on signal of (19)F NMR/MRI. In the present study, we conducted a systematic investigation of the relationship between structure and properties of the probe to elucidate the mechanism of this turn-on (19)F NMR sensing in detail. Newly synthesized (19)F probes showed three distinct behaviors in response to the target protein: off/on, always-on, and always-off modes. We clearly demonstrated that these differences in protein response could be explained by differences in the stability of the probe aggregates and that "moderate stability" of the aggregates produced an ideal turn-on response in protein detection. We also successfully controlled the aggregate stability by changing the hydrophobicity/hydrophilicity balance of the probes. The detailed understanding of the detection mechanism allowed us to rationally design a turn-on (19)F NMR probe with improved sensitivity, giving a higher image intensity for the target protein in (19)F MRI. 相似文献
38.
Matsuyama Kiyoshi Mishima Kenji Hayashi Ken-ichiro Matsuyama Hideto 《Journal of nanoparticle research》2003,5(1-2):87-95
A novel preparation method is reported for the microencapsulation of TiO2 nanoparticles by rapid expansion of supercritical solution with a nonsolvent. A suspension of TiO2 nanoparticles in carbon dioxide containing a cosolvent and dissolved polymer is sprayed through a nozzle to atmospheric pressure. After rapid expansion, polymer microspheres were obtained. The microspheres do not tend to agglomerate, since the pure cosolvent is a nonsolvent for the polymer. The structure and morphology of microspheres were investigated by SEM, TEM and XRD. The obtained polymer microspheres are microcapsules of TiO2 nanoparticles. The mean particle diameter and particle size distribution of microcapsules, could be controlled by changing the polymer concentration, pre-expansion pressure, temperature and injection distance. The polymer feed compositions are more effective than other factors on the control of particle size. 相似文献
39.
Makito Yokoe Keigo Aoi Masahiko Okada 《Journal of polymer science. Part A, Polymer chemistry》2003,41(15):2312-2321
Novel copolycarbonates containing 1,4:3,6‐dianhydro‐D ‐glucitol or 1,4:3,6‐dianhydro‐D ‐mannitol units, with various methylene chain lengths, were synthesized by bulk and solution polycondensations, of several combinations of carbonate‐modified sugar derivatives and aliphatic diols. Bulk polycondensations of 1,4:3,6‐dianhydro‐2,5‐bis‐O‐(phenoxycarbonyl)‐D ‐glucitol or 1,4:3,6‐dianhydro‐2,5‐bis‐O‐(phenoxycarbonyl)‐D ‐mannitol with four α,ω‐alkanediols having methylene chain lengths of 4, 6, 8, and 10, respectively, at 180 °C afforded the corresponding copolycarbonates with number‐average molecular weight (Mn) values up to 19.2 × 103. 13C NMR analysis disclosed that these polymers had scrambled structures in which the sugar carbonate and aliphatic carbonate moieties were nearly randomly distributed along a polymer chain. However, solution polycondensations between 1,4:3,6‐dianhydro‐2,5‐bis‐O‐(p‐nitrophenoxycarbonyl)‐D ‐glucitol or 1,4:3,6‐dianhydro‐2,5‐bis‐O‐(p‐nitrophenoxycarbonyl)‐D ‐mannitol, and the α,ω‐alkanediols in sulfolane or dimethyl sulfoxide at 60 °C gave well‐defined copolycarbonates having regular structures consisting of alternating sugar carbonate and aliphatic carbonate moieties with Mn values up to 33.8 × 103. Differential scanning calorimetry demonstrated that all the copolycarbonates were amorphous with glass‐transition temperatures ranging from 1 to 65 °C, which decreased with increasing lengths of the methylene chain of the aliphatic diols. Additionally, all the copolycarbonates were stable up to 310–330 °C as estimated by thermogravimetric analysis. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2312–2321, 2003 相似文献
40.
Toyoki Matsuyama 《Physics letters. [Part B]》1985,158(3):255-263
Toward the construction of the gauge theory on a lattice without species doubling, we formulate the U(1) gauge-coupled Dirac equation on a finite element in (d + 1)-dimensional space-time. For massless (QED)2, we derive the vector current conservation and the axial anomaly. The reproduction of the axial anomaly indicates the resolution of the doubling problem. 相似文献