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121.
Jian‐Fei Bai Kento Yasumoto Taichi Kano Keiji Maruoka 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(26):8990-8993
A highly enantioselective synthesis of 1,4‐enynes is described that proceeds through an organocatalytic reaction between propargyl alcohols and trialkenylboroxines. Our strategy relies on acid‐mediated generation of the carbocationic intermediate from propargyl alcohols followed by enantioselective alkenylation with trialkenylboroxines. A range of chiral 1,4‐enynes were obtained in moderate to good yields with high levels of enantioselectivity. Use of a highly acidic chiral N‐triflyl phosphoramide catalyst, which has two distant Lewis basic oxygen atoms, was found to be crucial for both high reactivity and selectivity in the present reaction. 相似文献
122.
Shota OKUNO Toshihiro YAMASHITA Kengo SHIRADO Kenta KAWAMITSU Kaede YAMABE Yutaro ONISHI Taichi OGAMI Hiroto KAYASHIMA 《Physical Therapy Research》2021,24(3):225
Objective: The study aimed to demonstrate the significance of early postoperative physical therapy interventions on clinical outcomes by determining the influence of the distance walked under the supervision of a physical therapist in the early postoperative period after liver cancer. Methods: All consecutive patients who underwent surgery for liver cancer between April 2018 and March 2020 were eligible for enrollment in the study. The total walking distance during physical therapy till the third postoperative day was examined. The clinical outcomes comprised duration of postoperative hospital stay, time to independent walking, and occurrence of postoperative complications. For data analysis, the patients were divided into two groups: those who walked more than the median total distance (the long-distance group) and those who walked less than the median distance (the short-distance group). We used propensity score matching to match the background characteristics between the groups. Results: Of the 65 patients who were eligible, 14 patients were included in the two groups each, after matching. The long-distance walking group had a significantly shorter hospital stay (9.0 days vs. 11.0 days, p=0.008) and a shorter time to independent walking (3.5 days vs. 7.5 days, p=0.019) than the short-distance walking group. There were no significant differences in postoperative complications between the two groups (7.1% vs. 42.8%, p=0.08). Conclusion: In the early postoperative period after liver cancer surgery, increasing the walking distance under the supervision of a physical therapist is important for improving clinical outcomes. Further prospective studies are needed to confirm the findings of this study. 相似文献
123.
Preparation of arsenic‐containing white rice grains as calibration standards for X‐ray fluorescence analysis of total arsenic in cereals 下载免费PDF全文
Masaki Tatsumi Tetsuo Inui Kenta Hagiwara Atsushi Ohbuchi Yuya Koike Toshihiro Nakamura 《X射线光谱测定》2016,45(5):274-280
A preparation method of arsenic‐containing white rice grains as calibration standards was developed for the X‐ray fluorescence (XRF) analysis of arsenic in rice grains. Calibration standards were prepared by adding 10 g of white rice grains (from Japan) to 100 ml methanol‐containing dimethylarsinic acid corresponding to 2–100 µg arsenic. The mixture was heated, dried at 150 °C, cooled to room temperature, and then stored in a silica gel desiccator. A total of 5.0 g of each calibration standard was packed into a polyethylene cup (32 mm internal diameter and 23 mm height) covered with a 6‐µm‐thick polypropylene film and then analyzed by wavelength‐dispersive XRF spectrometry. The calibration curve for arsenic obtained from the white rice grains containing arsenic showed good linearity over a concentration range of 0.21–5.00 mg kg?1 arsenic. The limit of detection of arsenic was 0.080 mg kg?1. To check the reliability of the XRF method, the concentrations of arsenic in six samples of grain cereals and two samples of flour were compared with those obtained by atomic absorption spectrometry after acid decomposition. The values obtained by both analytical methods showed good agreement. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
124.
K. Matsuda K. Tamura M. Inui Y. Kajihara T. Nagao M. Yao M. Itou Y. Sakurai 《The European physical journal. Special topics》2011,196(1):95-107
We have carried out x-ray diffraction and small-angle x-ray scattering measurements of expanded fluid alkali metal rubidium
(Rb) and observed that the nearest neighbor distance decreases despite the fact that the average interatomic distance increases
with volume expansion, indicating that the attractive force among ions is enhanced. Such structural change emerges in the
density range where the fluid is still metallic. The density range also corresponds with the region where the instability
of the electron gas has been theoretically predicted, suggesting the modulation in the charge fluctuations of the electron
gas plays an essential role for such enhanced attraction among ions. Motivated by these unusual structural features, we have
moved on investigating the electronic state in expanded fluid Rb through synchrotron-based high-resolution Compton scattering
experiments. We have succeeded in measuring the Compton profile of fluid Rb using newly developed a high-pressure vessel for
the Compton scattering experiments. 相似文献
125.
T. Inui S. Terada H. Tamura N. Ichinose 《Fresenius' Journal of Analytical Chemistry》1982,311(5):492-495
Summary Selenium was determined in biological samples (tea and bovine liver, NBS, SRM 1577) by a combination of hydride generation with reducing tube, graphite furnace atomization and atomic absorption detection. The selenium was reduced by a pellet of sodium borohydride which was placed in a horizontal glass tube. 1.6–2.0 l/min of argon flow rate and 2400° C of atomization temperature were the best experimental conditions. Copper produces a severe effect on absorbance, even if present in only 2 times the amounts of selenium. Ion-exchange resin (Dowex 50 W-X8) was used for the separation of Cu, Ni and Co. A detection limit of 1 ng was obtained with a precision of 5–6%.
Paper read at the meeting of 9th ICAS/XXII CSI, Tokyo, September 1981 相似文献
Selenbestimmung durch Hydriderzeugung im Reduktionsrohr mit nachfolgender Graphitofen-AAS
Zusammenfassung Durch Kombination von Hydriderzeugung und Graphitofen-AAS wurde Selen in biologischen Proben (Tee, Rinderleber, NBS, SRM 1577) bestimmt. Die Reduktion erfolgte durch Natriumborhydrid in einem horizontalen Glasrohr. 1,6–2,0 l/min Argon und 2400° C Atomisierungstemperatur erwiesen sich als optimal. Kupfer übt selbst bei nur doppelter Menge einen störenden Einfluß aus. Zur Abtrennung von Cu, Ni und Co wurde ein Ionenaustauscher (Dowex 50W-X8) verwendet. Die Nachweisgrenze beträgt 1 ng bei einer Reproduzierbarkeit von 5–6%.
Paper read at the meeting of 9th ICAS/XXII CSI, Tokyo, September 1981 相似文献
126.
Summary The problem is to estimate the mean of ap-dimensional normal distribution in the situation where there is vague information that the mean vector might be equal to
zero vector. Minimax property of the preliminary test estimator obtained by the use of AIC (Akaike's Information Criterion)
procedure is discussed under a loss function which is based on Kullback-Leibler information measure and evaluates both an
error of model selection and that of estimation. Whenp is even, the minimaxity is shown to hold for small values ofp but not for large values. 相似文献
127.
Summary The utility of various organic solvents, such as acetates and ketones, for the CuDBC chelate extraction and subsequent atomic absorption spectrophotometric determination is studied. Methyl propionate was found to be the most sensitive solvent. Data for the different substances are presented.
Einfluß der Lösungsmittelextraktion auf die AAS-Bestimmung von Kupferspuren mit Zinkdibenzyldithiocarbamat
Zusammenfassung Die Verwendbarkeit verschiedener Lösungsmittel (Acetate und Ketone) für die Extraktion des CuDBC-Komplexes und anschließende atomabsorptions-spektralphotometrische Bestimmung wurde systematisch untersucht. Werte für die verschiedenen Substanzen werden angegeben. Die größte Empfindlichkeit kann mit Methylpropionat erzielt werden.
We wish to thank President Dr. Yawara Yoshitoshi and Prof. Dr. Nobuo Sakurai of Hamamatsu University School of Medicine, for their hospitality and encouragement. 相似文献
128.
129.
[structure: see text] Sphingomyelin nitrogen analogue 1 was designed and synthesized as a sphingomyelinase inhibitor. The synthesis was established by continuous Hofmann rearrangement and Crutius rearrangement as key steps in constructing the 3-hydroxy-1,2-diamine structure in the backbone of 1. This analogue showed moderate inhibitory activity toward SMase isolated from B. cereus. 相似文献
130.
Development of a molecular recognition ion gating membrane and estimation of its pore size control 总被引:5,自引:0,他引:5
Ito T Hioki T Yamaguchi T Shinbo T Nakao S Kimura S 《Journal of the American Chemical Society》2002,124(26):7840-7846
We have fabricated a molecular recognition ion gating membrane. This synthetic membrane spontaneously opens and closes its pores in response to specific solvated ions. In addition to this switching function, we found that this membrane could control its pore size in response to a known concentration of a specific ion. The membrane was prepared by plasma graft copolymerization, which filled the pores of porous polyethylene film with a copolymer of NIPAM (N-isopropylacrylamide) and BCAm (benzo[18]crown-6-acrylamide). NIPAM is well-known to have an LCST (lower critical solution temperature), at which its volume changes dramatically in water. The crown receptor of the BCAm traps a specific ion, and causes a shift in the LCST. Therefore, selectively responding to either K(+) or Ba(2+), the grafted copolymer swelled and shrank in the pores at a constant temperature between two LCSTs. The solution flux in the absence of Ba(2+) decreased by about 2 orders of magnitude over a solution flux containing Ba(2+). The pore size was estimated by the filtration of aqueous dextran solutions with various solute sizes. This revealed that the membrane changed its pore size between 5 and 27 nm in response to the Ba(2+) concentration changes. No such change was observed for Ca(2+) solutions. Furthermore, this pore size change occurred uniformly in all pores, as a clear cut-off value for a solute size that could pass through pores was always present. This membrane may be useful not only as a molecular recognition ion gate, but also as a device for spontaneously controlling the permeation flux and solute size. 相似文献