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排序方式: 共有432条查询结果,搜索用时 31 毫秒
91.
Sharma SC Kunieda H Esquena J Rodríguez Abreu C 《Journal of colloid and interface science》2006,299(1):297-304
The phase behavior and formation of self-assemblies in the ternary water/fluorinated surfactant (C(8)F(17)EO(10))/hydrophobic fluorinated polymer (C(3)F(6)O)(n)COOH system and the application of those assemblies in the preparation of mesostructured silica have been investigated by means of phase study, small angle X-ray scattering, and rheology. Hexagonal (H(1)), bicontinuous cubic (V(1)) with Ia3d symmetry, and polymer rich lamellar (L(alpha)(')) are observed in the ternary diagram. C(8)F(17)EO(10) molecules are dissolved in polymer rich aggregates, whereas (C(3)F(6)O)(n)COOH molecules are practically insoluble in the surfactant lamellar phase due to packing restrictions. Hence, two types of lamellar phases exist: one with surfactant rich (L(alpha)) and the other with polymer rich (L(alpha)(')) in the water/C(8)F(17)EO(10)/(C(3)F(6)O)(n)COOH system. As suggested by rheological measurements, worm-like micelles are present in C(8)F(17)EO(10) aqueous solutions but a rod-sphere transition takes place by solubilization of (C(3)F(6)O)(n)COOH. C(8)F(17)EO(10) acts as a structure directing agent for the preparation of hexagonal mesoporous silica by the precipitation method. The addition of (C(3)F(6)O)(n)COOH induces the formation of larger but disordered pores. 相似文献
92.
Adsorbability and photocatalytic degradability of humic substances in water on Ti-modified silica 总被引:1,自引:0,他引:1
From the viewpoint of development of a removal agent for humic substances, we prepared Ti-modified silica gel, SiO2-Ti, from titanium alkoxide and microsized silica gel. The prepared silica agent was investigated in adsorption and photocatalytic degradation of humic substances in water. In these experiments, four humic substances, commercially available Wako humic acid (Wako-HA), Nordic aquatic humic acid (Nordic-HA), Nordic aquatic fulvic acid (Nordic-FA), and Suwannee river fulvic acid (Suwannee-FA), were used, and Freundlich constants (KF and 1/n) and photodegradation rates were evaluated. Wako-HA, which has the highest aromaticity ratio [Ar-OH]/[COOH] and molecular weight, had the highest adsorbability (KF=17.5 (mg/g)(L/mg)(1/n), 1/n=0.67) but the lowest photodegradability (<80%). On the other hand, Suwannee-FA, which has the lowest aromaticity, [Ar-OH]/[COOH] ratio, and molecular weight, afforded lesser adsorbability (KF=7.1 (mg/g)(L/mg)(1/n), 1/n=0.39) but the highest photodegradability (>99%). Nordic-HA and Nordic-FA afforded adsorbabilities similar to that for Suwannee-FA, and medium photodegradabilities between those for Wako-HA and Suwannee-FA. Adsorption and photodegradation capacities of SiO2-Ti were improved with increased Ti content and phosphorescence emission amount, respectively. From XRD analysis, we found that the structure of anatase-type TiO2 features the Ti modifiers of SiO2-Ti. Therefore, humic substance molecules effectively interact with the Ti modifiers and are decomposed by OH radicals generated in situ. We hope that SiO2-Ti will be used as a photodegradation catalyst in water purification plants. 相似文献
93.
M Albrecht Y Shang K Hasui V Gossen G Raabe K Tahara Y Tobe 《Dalton transactions (Cambridge, England : 2003)》2012,41(31):9316-9322
Triangular triscatechol ligands are prepared in facile reaction sequences. The catechol units are either bound to the triangular backbone through their 3- or 4-position. With titanium(IV) ions, the ligands form metallosupramolecular M(4)L(4) tetrahedra which are characterized by ESI MS and proton NMR. Quantum-chemical calculations reveal that connectivity at the catechol in the 3-position results in highly condensed structures while attachment in the 4-position affords container molecules providing huge internal cavities. 相似文献
94.
95.
Matsuura S Yokoyama T Ishii R Itoh T Tomon E Hamakawa S Tsunoda T Mizukami F Nanbu H Hanaoka TA 《Chemical communications (Cambridge, England)》2012,48(56):7058-7060
A flow-type microreactor containing glutaminase-mesoporous silica composites with 10.6 nm pore diameter (TMPS10.6) was developed for the continuous synthesis of theanine, a unique amino acid. High enzymatic activity was exhibited by the local control of the reaction temperature. 相似文献
96.
Hironobu Kunieda Hamidul Kabir Kenji Aramaki Kazuki Shigeta 《Journal of Molecular Liquids》2001,90(1-3):157-166
Cloud temperatures, phase behavior, and the structures of liquid crystals were investigated in the aqueous systems of homogenous hexaethylene glycol dodecyl ether(C12EO6) and mixed C12EO4-C12EO8, C12EO2-EO8, C12EO2-C12EO8, and C12EO0-C12EO8 In the mixed surfactant systems, the average polyoxyethylene- (EO-) chain lengths are kept constants, the same as C12EO6. The change in cloud temperatures is small in all the systems, whereas the phase behavior is successively changed with increasing the difference in EO-chain length in the mixture. Lamellar liquid crystal is developed in the phase diagrams and it intrudes in the two-phase region above the cloud temperature. Hence, the phase pattern of the present mixed surfactant systems resembles that of C12EO5 system, but both cloud point and W+L region appear at much higher temperature. Hence, the Hydrophile-Lipophile Balance of the surfactant is not largely changed by mixing the surfactants but the SAXS results show that the surfactant molecules are more tightly packed in the hexagonal and lamellar phases by mixing. It is considered that when surfactants of different EO-chain lengths are mixed, the considerable reduction in repulsion between the hydrophilic moieties takes place and the surfactant molecules are more tightly packed. 相似文献
97.
Koutaro Shiraishi Hironobu Koseki Toshiyuki Tsurumoto Koumei Baba Mariko Naito Koji Nakayama Hiroyuki Shindo 《Surface and interface analysis : SIA》2009,41(1):17-22
Photocatalysis with anatase Titanium dioxide (TiO2) under ultraviolet A (UVA) has a well recognized bactericidal effect. There have been a few reports, however, on the effects of photocatalysis on bio‐implant‐related infections. The purpose of present study was to evaluate the photocatalytic bactericidal effects of anatase TiO2 on Staphylococcus aureus (S. aureus) associated with surgical site infections. TiO2 films were synthesized on commercially pure titanium substrates and SUS316 stainless steel using a plasma source ion implantation method followed by annealing. The chemical composition of the surface layers was determined using GXRD and XPS. The disks were seeded with cultured S. aureus and exposed to UVA illumination from black light. The bactericidal effect of the TiO2 films was evaluated by counting the survived colonies statistically. A structural gradient anatase type TiO2 layer formed on all substrates. The viability of the bacteria on the photocatalytic TiO2 film coated on titanium was suppressed to 7.0% at 30 minutes and 5.5% at 45 minutes, whereas that on a similarly coated stainless steel was suppressed to 45.8% at 30 minute and 28.6% at 45 minutes (ANOVA: p < 0.05). Complete bacterial inactivation was achieved after 90 minutes on titanium and after 60 minutes on stainless steel. The photocatalytic bactericidal effect of TiO2 is useful for sterilizing the contaminated surfaces of bioimplants. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
98.
Dr. Masafumi Ueda Akimi Tahara Dr. Masashi Hasegawa Dr. Takashi Shirahata Prof. Dr. Yasuhiro Mazaki Prof. Dr. Yohji Misaki 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(19):4984-4991
[5]Radialene with quintuple 4,5-benzo-1,3-dithiol-2-ylidenes (DTs) easily forms a stable polycationic salt ( 1 )4+(BF4−)4 owing to its aromatic character in the central cyclopentadienide ring. In this work, it was found that the polycationic salt ( 1 )4+ underwent a hydration reaction in moist polar solvent to give several unexpected products, namely, an oxygen adduct dicationic salt ( 2 )2+, a tetrathiafulvalene (TTF) vinylogue ( 3 ) with 1,4-dithiine-2(3H)-one moieties, and an oxygen adduct of π-extended TTF with a cyclopentenone core ( 4 ). Their molecular structures were fully determined by X-ray crystal-structure analysis. In this reaction, irreversible hydration to the polycationic salt might either initiate the ring expansion and lead to the successive hydration at the specific cationic DT ring (for 3 ), or promote the transannular reactions to the next DT ring followed by elimination of the DT ring (for 4 ). Cyclic voltammetry and differential pulse voltammetry measurements for compound 3 indicated the occurrence of multi redox process resulting from electronic delocalization on the vinylogous TTF moiety. The electronic structures of the cationic species of 3 were also investigated by electronic spectra. 相似文献
99.
Dr. Keishiro Tahara Nazuna Terashita Dr. Ken Tokunaga Shiomi Yabumoto Prof. Jun-ichi Kikuchi Dr. Yoshiki Ozawa Prof. Masaaki Abe 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(60):13728-13738
Realization of molecular quantum cellular automata (QCA), a promising architecture for molecular computing through current-free processes, requires improved understanding and application of mixed-valence (MV) molecules. In this report, we present an electrostatic approach to creating MV subspecies through internalizing opposite charges in close proximity to MV ionic moieties. This approach is demonstrated by unsymmetrically attaching a charge-responsive boron substituent to a well-known organometallic MV complex, biferrocenium. Guest anions (CN− and F−) bind to the Lewis acidic boron center, leading to unusual blue-shifts of the intervalence charge-transfer (IVCT) bands. To the best of our knowledge, this is the first reported example of a zwitterionic MV series in which the degree of positive charge delocalization can be varied by changing the bound anions, and serves to clarify the interplay between IVCT parameters. The key underlying factor is the variable zero-level energy difference in the MV states. This work provides new insight into imbuing MV molecules with external charge-responsiveness, a prerequisite of molecular QCA techniques. 相似文献
100.
Prof. Hidemitsu Uno Kota Muramatsu Shogo Hiraoka Hiroyuki Tahara Mako Hirose Eidai Tamura Tatsumi Shiraishi Dr. John Mack Prof. Nagao Kobayashi Dr. Shigeki Mori Dr. Tetsuo Okujima Dr. Masayoshi Takase 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(25):5701-5708
A bicyclo[2.2.2]octadiene(BCOD)-fused bis(dipyrromethane) derivative was reacted with methylal in the presence of trifluoroacetic acid followed by oxidation with chloranil to give a doubly N-confused phlorin derivative, which did not undergo the retro-Diels–Alder reaction extruding an ethylene molecule on heating. In contrast, a 7-tert-butoxybicyclo[2.2.1]heptadiene(7-BuOBCHD)-fused bis(dipyrromethane) yielded benzene-ring-fused doubly N-confused porphyrins by following similar reaction sequences. 相似文献