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11.
12.
A simple and efficient method for the -deprotection of tetrahydropyranyl and 4,4′-dimethoxytrityl ethers using iodine in methanol is described. 相似文献
13.
Sakamoto M Takeba K Sasamoto T Kusano T Hayashi H Kanai S Kanda M Nagayama T 《Journal of AOAC International》2010,93(4):1340-1346
LC/MS/MS was developed to determine the residues of bithionol (BTN), bromofen (BMF), nitroxynil (NTX), oxyclozanide (OCZ), and tribromsalan (TBS) in milk. Samples were extracted with ethyl acetate and cleaned up by liquid-liquid separation with acetonitrile and n-hexane. The compounds were determined by RP-LC using a C18 column with 0.1% formic acid-methanol. Mass spectral acquisition was performed in the negative mode by applying selected-reaction monitoring. The method was validated in milk spiked with these compounds at 5-600 microg/kg; average recoveries were in the range 83.8-97.1%, with RSD values of 1.4-8.0%. The interassay RSDs were less than 11%. The LODs of these compounds in milk were 0.1 microg/kg. The method was applied to 24 raw milk samples. The concentration of these compounds in all samples was lower than the Japanese maximum residue limits. The method is rapid, sensitive, and specific for monitoring residues of BTN, BMF, NTX, OCZ, and TBS in milk. 相似文献
14.
Aratono M Onimaru N Yoshikai Y Shigehisa M Koga I Wongwailikhit K Ohta A Takiue T Lhoussaine B Strey R Takata Y Villeneuve M Matsubara H 《The journal of physical chemistry. B》2007,111(1):107-115
The concentration vs composition diagram of aggregate formation of the dodecyltrimethylammonium bromide (DTAB) and didodecyldimethylammonium bromide (DDAB) mixture in aqueous solution at rather dilute region was constructed by analyzing the surface tension, turbidity, and electrical conductivity data and inspected by cryo-TEM images and dynamic light scattering data. Although the aqueous solution of DTAB forms only micelles, the transition from monomer to small aggregates and then to vesicle was found at 0.1 < X2 相似文献
15.
We have shown the Lennard-Jones (LJ) phase diagram for a slit-shaped nanopore by molecular simulations and thermodynamically
predicted the results with no adjustable parameter. With this success, LJ phase diagrams are predictable. In this study, the
freezing of an LJ CH4 capillary condensate under a tensile condition in a nonstructural carbon nanopore with a cylindrical geometry was examined
using molecular dynamics (MD) simulation. We employ a unit cell in contact with a bulk vapor phase, which is useful for the
determination of the bulk vapor pressure in equilibrium with the molecules in a pore. The MD simulation results show liquid-solid
(amorphous) phase transitions with a variation in the bulk vapor pressure. The frozen particles are arranged in concentric
circular regions along the wall similar to those reported by Maddox and Gubbins. The freezing points are determined from the
variations in density, enthalpy, arrangement, and structural functions. The obtained liquid-solid coexistence points are found
to exhibit a significant dependence of the freezing point on the equilibrium bulk vapor pressure, forming an extraordinarily
skewed curve on the p-T diagram, in contrast to the bulk phase coexistence that is represented by an almost vertical line.
The origin of the significant dependence is considered to be the Laplace effect on the capillary condensate similar to the
case with a slit-shaped pore. A simple model, which the authors earlier presented for slit-shaped nanopores, successfully
predicted the p-T relation of the freezing point for cylindrical nanopores as well. 相似文献
16.
Ochiai N Sasamoto K Kanda H Yamagami T David F Tienpont B Sandra P 《Journal of separation science》2005,28(9-10):1083-1092
A multi-residue method to determine 85 pesticides, including organochlorine pesticides, carbamates, organophosphorus pesticides, and pyrethroids, in vegetables, fruit, and green tea, has been developed. The method is based on stir bar sorptive extraction (SBSE) coupled to thermal desorption (TD) and retention time locked (RTL) GC-MS operating in the scan mode. Samples are extracted with methanol and diluted with water prior to SBSE. Dilution of the methanol extract before SBSE was optimized to obtain high sensitivity and to minimize adsorption onto the glass wall of the extraction vessel as well as to minimize sample matrix effects (particularly for the pesticides with high log K(o,w) values). The optimized method consists of a dual SBSE extraction performed simultaneously on respectively a twofold and a fivefold diluted methanol extract. After extraction, the two stir bars are placed in a single glass thermal desorption liner and are simultaneously desorbed. The method showed good linearity (r2 > 0.9900) and high sensitivity (limit of detection: < 5 microg kg(-1)) for most of the target pesticides. The method was applied to the determination of pesticides at low microg kg(-1) in tomato, cucumber, green soybeans, spinach, grapes, and green tea. 相似文献
17.
Yui Hayashi Noriharu Takada Wahyudiono Hideki Kanda Motonobu Goto 《Plasma Chemistry and Plasma Processing》2017,37(1):125-135
Pulsed discharge plasma is typical oxidation technology for disposing organic compounds in aqueous solutions. When this electrical discharge plasma was applied in water, it may produce hydrogen peroxide (H2O2) without any catalyst or chemical agent. In order to increase H2O2 production by electrical discharge plasma in water, fine bubbles were introduced into the electrical discharge plasma in this experiment. Bipolar pulsed voltages were applied to cylindrical electrodes in the water while Ar or O2 bubbles were introduced, generating a pulsed discharge plasma. The introduction of the bubbles seemed to enhance the dissociation of water molecules and increased H2O2 formation, especially with O2 bubbling. Dissolved oxygen in the water contributed to H2O2 formation by pulsed discharge plasma with the bubbles, while dissociation of water molecules was the cause of H2O2 formation by pulsed discharge plasma without bubbles. More H2O2 was formed by pulsed discharge plasma with O2 bubbles, because the amount of dissolved oxygen in the water increased upon bubbling with O2. 相似文献
18.
Chilling resistances of isolates of Pythium ultimum var. ultimum from the Arctic and Temperate Zones
Hoshino T Tojo M Kanda H Herrero ML Tronsmo AM Kiriaki M Yokota Y Yumoto I 《Cryo letters》2002,23(3):151-156
Chilling resistances in moss pathogenic fungi, Pythium ultimum var. ultimum, from Longyearbyen, Svalbard (78 degree N, 15 degree E), located in the Arctic Zone and in the same isolates from Temperate Zone, were determined. Both strains had similar optimum growth temperatures. However, the strains from Svalbard could grow and survive at 0 - 5 degrees C. In addition, chilling treatment induced irregular mycelial morphology in the Arctic isolates. On the other hand, the isolates from Japan did not grow at temperatures below 5C and were destroyed after chilling stress (0 degree C for 3 days or at 4 degrees C for 1 week). The results suggested that isolates from Svalbard highly adapted to the severe spring condition in Polar environments. 相似文献
19.
T. Kanda 《Annals of the Institute of Statistical Mathematics》1992,44(3):519-528
We consider the growth curve model with covariance structures: positive-definite, uniform covariance structure and serial covariance structure. Two types of prediction problems are studied in this paper. One is called the conditional prediction problem and the other is called the extended prediction problem. For both types of prediction problems, the mean squared error for a serial covariance structure is obtained for the estimates based on the conditional expectation: the mean squared error for an unrestricted covariance structure is compared with the mean squared error for a uniform covariance structure or a serial covariance structure. These results are exemplified by two sets of real data.This research was supported in part by Grant-in-Aid for general Scientific Research, The Ministry of Education, Science and Culture under Contract Number 03640239. 相似文献
20.
Within the framework of the LCAO -MO theory, a novel sign-alternation rule has been found empirically for the lowest excited ππ* triplet state in the alternant aromatic system. This rule can be applied to identify the phosphorescent state. 相似文献