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751.
Tokitoh N Nakata N Shinohara A Takeda N Sasamori T 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(6):1856-1862
The first stable eta6-germabenzene complexes, that is, [M(CO)3(eta6-C5H5GeTbt)] {M=Cr (2), Mo (3), and W (4); Tbt=2,4,6-tris[bis(trimethylsilyl)methyl]phenyl}, have been synthesized by ligand-exchange reactions between [M(CO)3(CH3CN)3] (M=Cr, Mo, and W) and the kinetically stabilized germabenzene 1 and characterized by 1H and 13C NMR, IR, and UV/Vis spectroscopy. In the 1H and 13C NMR spectra of 2-4, all of the signals for the germabenzene rings were shifted upfield relative to their counterparts in the free germabenzene 1. X-ray crystallographic analysis of 2 and 4 revealed that the germabenzene ligand was nearly planar and was coordinated to the M(CO)3 group (M=Cr, W) in an eta6 fashion. The formation of complexes 2-4 from germabenzene 1 should be noted as the application of germaaromatics as 6pi-electron ligands toward complexation with Group 6 metals. On the other hand, treatment of 1 with [{RuCp*Cl}4] (Cp*=C5Me5) in THF afforded a novel eta5-germacyclohexadienido complex of ruthenium-[RuCp*{eta5-C5H5GeTbt(Cl)}] (9)-instead of the expected eta6-germabenzene-ruthenium cationic complex [RuCp*{eta6-C5H5GeTbt}]Cl (10). Crystallographic structural analysis of 9 showed that the five carbon atoms of the germacyclohexadienido ligand of 9 were coordinated to the Ru center in an eta5 fashion. 相似文献
752.
[structure: see text] New isobisvertinol and known bisvertinol were isolated from the culture broth of Aspergillus sp. FKI-1746. Isobisvertinol with the two alkenyl side chains extending in the same direction inhibited lipid droplet accumulation in macrophages, whereas bisvertinol with those extending in the reverse direction had almost no effect on the accumulation. 相似文献
753.
Uchida H Miyata K Oba M Ishii T Suma T Itaka K Nishiyama N Kataoka K 《Journal of the American Chemical Society》2011,133(39):15524-15532
A series of the N-substituted polyaspartamides possessing repeating aminoethylene units in the side chain was prepared in this study to identify polyplexes with effective endosomal escape and low cytotoxicity. All cationic N-substituted polyaspartamides showed appreciably lower cytotoxicity than that of commercial transfection reagents. Interestingly, a distinctive odd-even effect of the repeating aminoethylene units in the polymer side chain on the efficiencies of endosomal escape and transfection to several cell lines was observed. The polyplexes from the polymers with an even number of repeating aminoethylene units (PA-Es) achieved an order of magnitude higher transfection efficiency, without marked cytotoxicity, than those of the polymers with an odd number of repeating aminoethylene units (PA-Os). This odd-even effect agreed well with the buffering capacity of these polymers as well as their capability to disrupt membrane integrity selectively at endosomal pH, leading to highly effective endosomal escape of the PA-E polyplexes. Furthermore, the formation of a polyvalent charged array with precise spacing between protonated amino groups in the polymer side chain was shown to be essential for effective disruption of the endosomal membrane, thus facilitating transport of the polyplex into the cytoplasm. These data provide useful knowledge for designing polycations to construct safe and efficient nonviral gene carriers. 相似文献
754.
Okuda M Ogawa N Takeguchi M Hashimoto A Tagaya M Chen S Hanagata N Ikoma T 《Microscopy and microanalysis》2011,17(5):788-798
The mineralized structure of aligned collagen fibrils in a tilapia fish scale was investigated using transmission electron microscopy (TEM) techniques after a thin sample was prepared using aqueous techniques. Electron diffraction and electron energy loss spectroscopy data indicated that a mineralized internal layer consisting of aligned collagen fibrils contains hydroxyapatite crystals. Bright-field imaging, dark-field imaging, and energy-filtered TEM showed that the hydroxyapatite was mainly distributed in the hole zones of the aligned collagen fibrils structure, while needle-like materials composed of calcium compounds including hydroxyapatite existed in the mineralized internal layer. Dark-field imaging and three-dimensional observation using electron tomography revealed that hydroxyapatite and needle-like materials were mainly found in the matrix between the collagen fibrils. It was observed that hydroxyapatite and needle-like materials were preferentially distributed on the surface of the hole zones in the aligned collagen fibrils structure and in the matrix between the collagen fibrils in the mineralized internal layer of the scale. 相似文献
755.
Ma YuGang Fang DeQing Sun XiaoYan Zhou Pei Cai XiangZhou Chen JinGen Guo Wei Tian WenDong Wang HongWei Zhang GuoQiang Cao XiGuang Fu Yao Hu ZhengGuo Wang JianSong Wang Meng Togano Y. Aoi N. Baba H. Honda T. Okada K. Hara Y. Ieki K. Ishibashi Y. Itou Y. Iwasa N. Kanno S. Kawabata T. Kimura H. Kondo Y. Kurita K. Kurokawa M. Moriguchi T. Murakami H. Oishi H. Ota S. Ozawa A. Sakurai H. Shimoura S. Shioda R. Takeshita E. Takeuchi S. Yamada K. Yamada Y. Yasuda Y. Yoneda K. Motobayashi T. 《中国科学:物理学 力学 天文学(英文版)》2011,54(1):18-23
Two-proton relative momentum distributions from the break-up channels 23Al→p+p+21Na and 22Mg→p+p+20Ne at an energy of 60–70 A MeV have been measured together with two-proton opening angles at the projectile fragment separator beamline (RIPS) in the RIKEN Ring Cyclotron Facility. The results demonstrate the existence of diproton emission component from single-step 2He for highly excited 23Al and 22Mg. 相似文献
756.
Katsumata K Ohno Y Tomita K Sakai M Nakajima A Kakihana M Fujishima A Matsushita N Okada K 《Photochemistry and photobiology》2011,87(5):988-994
Titanium dioxide thin films were prepared by using four water-soluble titanium complexes of titanium-lactate, tartalate, malate and salicylate complex solutions. The crystalline phases detected in the films were anatase. The surface microstructures of the four film samples were different in their grain sizes. Photocatalytic decomposition activity of the four films was almost the same, but their photoinduced hydrophilicities were different. The film prepared using titanium-salicylate complex exhibited lower hydrophilic conversion rate than the other films. Grain size and stress yielded to the film are considered to be important factors on the photoinduced hydrophilicity. 相似文献
757.
Norihiro Tokitoh Daisuke Shimizu Nobuhiro Takeda Takahiro Sasamori 《Phosphorus, sulfur, and silicon and the related elements》2013,188(5-6):1241-1245
Abstract New types of o-phenylene-bridged polythioethers tethered with extremely bulky aryl groups at their terminal sulfur atoms, such as TbtS(o-Phen)S(o-Phen)S(o-Phen)STbt (1) and TbtS(o-Phen)S(o-Phen)SS(o-Phen)S(o-Phen)STbt (2) (Tbt = 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl, o-Phen = o-phenylene), were synthesized and subjected to the complexation with several kinds of late-transition metals. In the case of polythioether 1, the reaction with RhCl3·3H2O in benzene/EtOH resulted in the formation of a unique bimetallic complex, in which a part of ligand 1 is lost and the resulting sulfur atom is directly bound to the other Rh metal center. Interestingly, similar treatment of 1 with IrCl3·3H2O afforded ethyl-coordinated mononuclear Ir complex. Furthermore, 1 underwent complexation with Na2PdCl4 in EtOH to give the corresponding square planar dichloropalladium complex coordinated with two inner sulfur atoms of 1, while the S6-ligand 2 reacted with excess of Pd(PPh3)4 in benzene to afford a quite interesting trinuclear Pd complex multi-step metal insertion reactions. 相似文献
758.
Yoshinori Maeda Frederico Pittella Takahiro Nomoto Hiroyasu Takemoto Nobuhiro Nishiyama Kanjiro Miyata Kazunori Kataoka 《Macromolecular rapid communications》2014,35(13):1211-1215
For efficient delivery of siRNA into the cytoplasm, a smart block copolymer of poly(ethylene glycol) and charge‐conversion polymer (PEG‐CCP) is developed by introducing 2‐propionic‐3‐methylmaleic (PMM) amide as an anionic protective group into side chains of an endosome‐disrupting cationic polyaspartamide derivative. The PMM amide moiety is highly susceptible to acid hydrolysis, generating the parent cationic polyaspartamide derivative at endosomal acidic pH 5.5 more rapidly than a previously synthesized cis‐aconitic (ACO) amide control. The PMM‐based polymer is successfully integrated into a calcium phosphate (CaP) nanoparticle with siRNA, constructing PEGylated hybrid micelles (PMM micelles) having a sub‐100 nm size at extracellular neutral pH 7.4. Ultimately, PMM micelles achieve the significantly higher gene silencing efficiency in cultured cancer cells, compared to ACO control micelles, probably due to the efficient endosomal escape of the PMM micelles. Thus, it is demonstrated that fine‐tuning of acid‐labile structures in CCP improves the delivery performance of siRNA‐loaded nanocarriers.
759.
Partial Charge Transfer in the Shortest Possible Metallofullerene Peapod,La@C82⊂[11]Cycloparaphenylene 下载免费PDF全文
Takahiro Iwamoto Dr. Zdenek Slanina Dr. Naomi Mizorogi Dr. Jingdong Guo Prof. Dr. Takeshi Akasaka Shigeru Nagase Dr. Hikaru Takaya Dr. Nobuhiro Yasuda Prof. Dr. Tatsuhisa Kato Prof. Dr. Shigeru Yamago 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(44):14403-14409
[11]Cycloparaphenylene ([11]CPP) selectively encapsulates La@C82 to form the shortest possible metallofullerene–carbon nanotube (CNT) peapod, La@C82?[11]CPP, in solution and in the solid state. Complexation in solution was affected by the polarity of the solvent and was 16 times stronger in the polar solvent nitrobenzene than in the nonpolar solvent 1,2‐dichlorobenzene. Electrochemical analysis revealed that the redox potentials of La@C82 were negatively shifted upon complexation from free La@C82. Furthermore, the shifts in the redox potentials increased with polarity of the solvent. These results are consistent with formation of a polar complex, (La@C82)δ??[11]CPPδ+, by partial electron transfer from [11]CPP to La@C82. This is the first observation of such an electronic interaction between a fullerene pea and CPP pod. Theoretical calculations also supported partial charge transfer (0.07) from [11]CPP to La@C82. The structure of the complex was unambiguously determined by X‐ray crystallographic analysis, which showed the La atom inside the C82 near the periphery of the [11]CPP. The dipole moment of La@C82 was projected toward the CPP pea, nearly perpendicular to the CPP axis. The position of the La atom and the direction of the dipole moment in La@C82?[11]CPP were significantly different from those observed in La@C82?CNT, thus indicating a difference in orientation of the fullerene peas between fullerene–CPP and fullerene–CNT peapods. These results highlight the importance of pea–pea interactions in determining the orientation of the metallofullerene in metallofullerene–CNT peapods. 相似文献
760.
Prof. Dr. Masayuki Endo Seigi Yamamoto Tomoko Emura Kumi Hidaka Dr. Nobuhiro Morone Prof. Dr. John E. Heuser Prof. Dr. Hiroshi Sugiyama 《Angewandte Chemie (International ed. in English)》2014,53(29):7484-7490
We developed a novel method to design various helical tubular structures using the DNA origami method. The size‐controlled tubular structures which have 192, 256, and 320 base pairs for one turn of the tube were designed and prepared. We observed the formation of the expected short tubes and unexpected long ones. Detailed analyses of the surface patterns of the tubes showed that the short tubes had mainly a left‐handed helical structure. The long tubes mainly formed a right‐handed helical structure and extended to the directions of the double helical axes as structural isomers of the short tubes. The folding pathways of the tubes were estimated by analyzing the proportions of short and long tubes obtained at different annealing conditions. Depending on the number of base pairs involved in one turn of the tube, the population of left‐/right‐handed and short/long tubes changed. The bending stress caused by the stiffness of the bundled double helices and the non‐natural helical pitch determine the structural variety of the tubes. 相似文献