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391.
Yasufumi Takahashi Yu Kobayashi Ziqian Wang Yoshikazu Ito Masato Ota Hiroki Ida Akichika Kumatani Keisuke Miyazawa Takeshi Fujita Hitoshi Shiku Yuri E. Korchev Yasumitsu Miyata Takeshi Fukuma Mingwei Chen Tomokazu Matsue 《Angewandte Chemie (International ed. in English)》2020,59(9):3601-3608
High‐resolution scanning electrochemical cell microscopy (SECCM) is used to image and quantitatively analyze the hydrogen evolution reaction (HER) catalytically active sites of 1H‐MoS2 nanosheets, MoS2, and WS2 heteronanosheets. Using a 20 nm radius nanopipette and hopping mode scanning, the resolution of SECCM was beyond the optical microscopy limit and visualized a small triangular MoS2 nanosheet with a side length of ca. 130 nm. The electrochemical cell provides local cyclic voltammograms with a nanoscale spatial resolution for visualizing HER active sites as electrochemical images. The HER activity difference of edge, terrace, and heterojunction of MoS2 and WS2 were revealed. The SECCM imaging directly visualized the relationship of HER activity and number of MoS2 nanosheet layers and unveiled the heterogeneous aging state of MoS2 nanosheets. SECCM can be used for improving local HER activities by producing sulfur vacancies using electrochemical reaction at the selected region. 相似文献
392.
It has been computationally proposed that there are more than 200 possible isomeric structures for the C6H6 molecule, among which benzene (CH)6 represents the most thermodynamically stable molecule and its chemistry has been extensively developed. Three benzene valence isomers (CR)6, namely, prismane, Dewar benzene, and benzvalene, have also been synthesized to date. Incorporation of heteroatoms in the skeletal frameworks allows access to inorganic analogues of benzene and its valence isomers, which have attracted considerable attention due to their peculiar structural and electronic features. Experimentally, more than 30 examples of inorganic benzene and its valence isomers have been developed and characterized so far. In this contribution, their synthesis and characterization, as well as their stability and chemical properties, are discussed. 相似文献
393.
Sawamura K Yoshida K Suzuki A Motozaki T Kozawa I Hayamizu T Munakata R Takao K Tadano K 《The Journal of organic chemistry》2007,72(16):6143-6148
Total syntheses of the antimicrobial tricyclic 16-membered macrolides, (+)-tubelactomicin B, (+)-tubelactomicin D, and (+)-tubelactomicin E, have been accomplished for the first time with common synthetic approaches. These total syntheses established the relative and absolute configurations of the three tubelactomicins, for which planar structures had solely been reported. The total synthesis of (+)-tubelactomicin D included a newly developed stereoselective intramolecular Diels-Alder reaction for constructing the highly functionalized octahydronaphthalene substructures. 相似文献
394.
Nishimura S Li Z Watanabe H Yoshinaga K Sumikama T Tachibana T Yamaguchi K Kurata-Nishimura M Lorusso G Miyashita Y Odahara A Baba H Berryman JS Blasi N Bracco A Camera F Chiba J Doornenbal P Go S Hashimoto T Hayakawa S Hinke C Ideguchi E Isobe T Ito Y Jenkins DG Kawada Y Kobayashi N Kondo Y Krücken R Kubono S Nakano T Ong HJ Ota S Podolyák Z Sakurai H Scheit H Steiger K Steppenbeck D Sugimoto K Takano S Takashima A Tajiri K Teranishi T Wakabayashi Y Walker PM Wieland O Yamaguchi H 《Physical review letters》2011,106(5):052502
The β-decay half-lives of 38 neutron-rich isotopes from (36)Kr to (43)Tc have been measured; the half-lives of (100)Kr, (103-105)Sr, (106-108)Y, (108-110)Zr, (111,112)Nb, (112-115)Mo, and (116,117)Tc are reported here. The results when compared with previous standard models indicate an overestimation in the predicted half-lives by a factor of 2 or more in the A≈110 region. A revised model based on the second generation gross theory of β decay better predicts the measured half-lives and suggests a more rapid flow of the rapid neutron-capture process (r-matter flow) through this region than previously predicted. 相似文献
395.
Prof. Dr. Koji Kano Toshiro Ochi Sayuri Okunaka Yusuke Ota Keiichi Karasugi Takunori Ueda Dr. Hiroaki Kitagishi 《化学:亚洲杂志》2011,6(11):2946-2955
Poly(acrylic acid) (PAA) is modified by 5‐(4‐β‐alanylaminophenyl)‐10,15,20‐tris(4‐sulfonatophenyl) porphinatoiron(III) to yield iron porphyrin‐bearing PAAs (FeP(n)s) through a condensation reaction. FeP(n)s were further functionalized by Py3CD, which is a per‐O‐methylated β‐cyclodextrin (CD) dimer with a pyridine linker and includes the porphyrin pendants to form ferric hemoCD‐P(n)s. Ferrous hemoCD‐P(3), having three porphyrin chromophores in a polymer chain, is shown to bind molecular oxygen (P1/2=7.9±1.4 Torr) in aqueous solution at pH 7.0 and 25 °C, affording oxy‐hemoCD‐P(3). Oxy‐hemoCD‐P(3) is biphasically autoxidized to ferric hemoCD‐P(3), with 27 % of the dioxygen adducts being rapidly oxidized. The rate of autoxidation of oxy‐hemoCD‐P(15), having 15 porphyrin chromophores in a polymer chain, was much faster than that of oxy‐hemoCD‐P(3), thus suggesting self‐catalyzed autoxidation of oxy‐hemoCD‐P(n)s. Oxy‐hemoCD‐P(n)s are markedly stabilized by catalase, thereby indicating that hydrogen peroxide generated from oxy‐hemoCD‐P(n) accelerates the autoxidation. Most of the hemoCD‐P(3) molecules injected into the femoral vein of a rat remained in the body, though about 16 % of the hemoCD‐P(3) molecules were excreted in the urine as a carbon monoxide adduct. 相似文献
396.
Hayasaka T Goto-Inoue N Ushijima M Yao I Yuba-Kubo A Wakui M Kajihara S Matsuura M Setou M 《Analytical and bioanalytical chemistry》2011,401(1):183-193
Imaging mass spectrometry (IMS) is a powerful tool for detecting and visualizing biomolecules in tissue sections. The technology
has been applied to several fields, and many researchers have started to apply it to pathological samples. However, it is
very difficult for inexperienced users to extract meaningful signals from enormous IMS datasets, and the procedure is time-consuming.
We have developed software, called IMS Convolution with regions of interest (ROI), to automatically extract meaningful signals
from IMS datasets. The processing is based on the detection of common peaks within the ordered area in the IMS dataset. In
this study, the IMS dataset from a mouse eyeball section was acquired by a mass microscope that we recently developed, and
the peaks extracted by manual and automatic procedures were compared. The manual procedure extracted 16 peaks with higher
intensity in mass spectra averaged in whole measurement points. On the other hand, the automatic procedure using IMS Convolution
easily and equally extracted peaks without any effort. Moreover, the use of ROIs with IMS Convolution enabled us to extract
the peak on each ROI area, and all of the 16 ion images on mouse eyeball tissue were from phosphatidylcholine species. Therefore,
we believe that IMS Convolution with ROIs could automatically extract the meaningful peaks from large-volume IMS datasets
for inexperienced users as well as for researchers who have performed the analysis. 相似文献
397.
Hanada Y Sugioka K Shihira-Ishikawa I Kawano H Miyawaki A Midorikawa K 《Lab on a chip》2011,11(12):2109-2115
Phormidium, a genus of filamentous cyanobacteria, forms endosymbiotic associations with seedling roots that accelerate the growth of the vegetable seedlings. Understanding the gliding mechanism of Phormidium will facilitate improved formation of this association and increased vegetable production. To observe the gliding movements, we fabricated various microfluidic chips termed nanoaquariums using a femtosecond (fs) laser. Direct fs laser writing, followed by annealing and successive wet etching in dilute hydrofluoric acid solution, can easily produce three-dimensional (3D) microfluidics with different structures embedded in a photostructurable glass. Using the fs laser, optical waveguides and filters were integrated with the microfluidic structures in the microchips, allowing the gliding mechanism to be more easily clarified. Using this apparatus, we found that CO(2) secreted from the seedling root attracts Phormidium in the presence of light, and determined the light intensity and specific wavelength necessary for gliding. 相似文献
398.
399.
In order to obtain cell microarrays formed with human promyelocytic leukemia cells (HL-60), biotinylation of methacryloyl-functionalized HL-60 cells was performed via a thiol-ene reaction with thiol-terminated 4-arm poly(ethylene glycol) (PEG(4)10K-SH). Biotinylated HL-60 cells were selectively adhered onto an avidin-patterned surface with high viability. 相似文献
400.