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981.
Ohyama K Shirasawa Y Wada M Kishikawa N Ohba Y Nakashima K Kuroda N 《Journal of chromatography. A》2004,1042(1-2):189-195
A novel packing material, 3-(4-sulfo-1,8-naphthalimido)propyl-modified silyl silica gel (SNAIP), was prepared for the use as a stationary phase of capillary electrochromatography (CEC). The sulfonic acid groups on SNAIP stationary phase contributed to the generation of electroosmotic flow (EOF) at low pH and served as a strong cation-exchanger. In CEC with SNAIP, a mixed-mode separation was predicted, comprising hydrophobic and electrostatic interactions as well as electrophoretic migration process. In order to understand the retention mechanism on SNAIP, effects of buffer pH, concentration, and mobile phase composition on EOF mobility and the retention factors of barbiturates and benzodiazepines were systematically investigated. Moreover, the retention behavior of barbiturates on SNAIP was investigated and compared with those on octadecyl silica (ODS), phenyl-bonded silica, and 3-(1,8-naphthalimido)propyl-modified silyl silica gel to confirm the presence of pi-pi interaction on its retention mechanism. It was observed that a column efficiency was more than 85,000 N/m for retained compounds and the relative standard deviations for the retention times of EOF marker, thiourea, and five barbiturates were below 2.5% (n = 4). Under an applied voltage of 20 kV and a mobile phase consisted of 5 mM phosphate (pH 3.8) and 40% methanol, the baseline separation of five barbiturates was achieved within 3 min. 相似文献
982.
Tohru Nakashima 《Transactions of the American Mathematical Society》1997,349(12):4775-4786
Let be an algebraically closed field of characteristic . Let be a nonsingular projective variety defined over and an ample line bundle on . We shall prove that there exists an explicit number such that if is a -stable vector bundle of rank at most three, then the restriction is -stable for all and all smooth irreducible divisors . This result has implications to the geometry of the moduli space of -stable bundles on a surface or a projective space.
983.
Reaction rate distributions in a plastic phantom were measured with solid state nuclear track detectors and a fission counter for 40- and 65-MeV quasi-monoenergetic neutrons generated by the 7Li(p,n) reactions with 43- and 68-MeV protons at AVF cyclotron of Japan Atomic Energy Research Institute. Measured distributions were compared with calculated ones. 相似文献
984.
This review includes our researches and other methodologies related to flow-based techniques, such as flow injection analysis (FIA) and sequential injection analysis (SIA). The methods will demonstrate semi-and full automated FIA and SIA, including liquid-liquid and liquid-solid extraction. FIA using alternative chemical reactions in the aqueous solution was applied to the trace analysis of metals in biological and environmental samples. For durable liquid-liquid extraction, several phase separators were designed. Moreover, multi-channel FIA with newly designed flow cells and SIA with lab-on-valve devices have been used for the simultaneous and successive determination of metals and organic compounds. On-line solid phase extraction (SPE) has also been proposed for highly sensitive analysis of organic and inorganic compounds. 相似文献
985.
Eiji Nakashima Kazuo Neriishi Atsushi Minamoto 《Annals of the Institute of Statistical Mathematics》2008,60(3):465-482
In analyses of bivariate ordered polytomous cataract data from atomic-bomb survivors, we compared two methods, the univariate
worse-eye method, and the bivariate generalized estimating equations (GEE’s) method using global odds ratio by Williamson
et al. (Journal of the American Statistical Association, 90, 1432–1437, 1995). When the association was large and only subject level covariates were used, model selection in the univariate
and bivariate methods resulted in the same mean model and similar risk estimates. We showed that the mean parameter and the
standard error (SE) in the univariate model are emphasized relative to those in the bivariate model, the biases of which are
negligible when the association between both eyes is large. Large sample simulation studies indicated that the univariate
Wald statistics are slightly conservative. The simulations also showed that, in bivariate cases, irrespective of the degree
of association, the independence estimating equations method with robust SE, and the GEE method with model-based and robust
SE are almost fully efficient in parameter estimation when only subject level covariates are included in the mean. 相似文献
986.
Le Thi Kim Dung Tomoki Imai Osamu Tomioka Mikio Nakashima Kuniaki Takahashi Yoshihiro Meguro 《Analytical sciences》2006,22(11):1425-1430
The supercritical fluid extraction (SFE) method using CO(2) as a medium with an extractant of HNO(3)-tri-n-butyl phosphate (TBP) complex was applied to extract uranium from several uranyl phosphate compounds and simulated uranium ores. An extraction method consisting of a static extraction process and a dynamic one was established, and the effects of the experimental conditions, such as pressure, temperature, and extraction time, on the extraction of uranium were ascertained. It was found that uranium could be efficiently extracted from both the uranyl phosphates and simulated ores by the SFE method using CO(2). It was thus demonstrated that the SFE method using CO(2) is useful as a pretreatment method for the analysis of uranium in ores. 相似文献
987.
Norihito Kijima Yuko Sakata Yasuhiko Takahashi Junji Akimoto Toshiya Kumagai Kaoru Igarashi Tadao Shimizu 《Solid State Ionics》2009,180(6-8):616-620
Single-phase specimens of α-MnO2 (hollandite-type) and β-MnO2 (rutile-type) were synthesized by the acid digestion of Mn2O3 under reflux conditions. The type of polymorph of MnO2 products was strongly dependent on the reaction temperature, type of acid used, and its concentration. The pH titration curve of α-MnO2 displayed a monobasic acid behavior toward Li+, but β-MnO2 showed a poor ion-exchange property. In contrast, both α-MnO2 and β-MnO2 acted as a rechargeable active material in a liquid organic electrolyte lithium cell. The initial discharge capacities of both electrodes exceeded 200 mAh/g (cut-off voltage: 2 V). After discharge–charge repetition, the α-MnO2 structure was still retained without structure collapse, although the β-MnO2 structure was destroyed. These findings show that Li+ ions can be inserted only into the hollandite-type tunnels in α-MnO2 and cannot diffuse the rutile-type linkages in α-MnO2 as well as those in β-MnO2 without structure collapse. 相似文献
988.
Seisuke Nakashima Koji Fujita Atsuo Nakao Katsuhisa Tanaka Yasuhiko Shimotsuma Kiyotaka Miura Kazuyuki Hirao 《Applied Physics A: Materials Science & Processing》2009,94(1):83-88
We report on spatially selective change of magnetism from paramagnetic to ferrimagnetic-like behaviors in normal spinel ZnFe2O4 thin film under irradiation with 780 nm femtosecond laser pulses. The distribution of Zn2+ and Fe3+ ions in the irradiated region on the film surface becomes disordered because of local heating to high temperatures, and the
metastable phase of ZnFe2O4 is frozen in by the rapid quenching after irradiation, resulting in the formation of the ferrimagnetic phase. The ferrimagnetic
phase reverts to the paramagnetic state by annealing at 800°C. The present technique is useful for two-dimensional patterning
of magnetic thin films. 相似文献
989.
The characteristics of our color vision are affected by various visual environments. In this experiment, we examined how colored lights look in dense fog. We used 12 kinds of colored light as a test stimulus. At first, in the absence of fog, subjects matched brightness of all the test stimuli with a reference white light adjusted to 0.1 cd/m2 or 0.5 cd/m2 in luminance, respectively. They then evaluated the apparent brightness of the test stimuli in dense fog with magnitude estimation of 10 grades. In the presence of fog, test stimuli containing a yellow component were given the highest point value of brightness, while test stimuli containing a blue component were given the lowest point value of brightness in fog. We are confident that in a visual environment involving fog, these results will be extremely helpful and practical. 相似文献
990.
A simple and convenient high performance liquid chromatographic method with UV detection is described for the determination of mazindol [5-(p-chlorophenyl)-2,5-dihydro-3H-imidazo[2,1-a]isoindol-5-ol] and its major metabolite, 2-(2-aminoethyl)-3-(p-chlorophenyl)-3-hydroxyphthalimidine (Met), in human plasma. The analytes were extracted with ethyl acetate from plasma samples and separated on a C18 column using acetonitrile-0.067 mol dm(-3) phosphate buffer (pH 3.5) (24 + 76 v/v) as a mobile phase. The eluates were monitored at 220 nm. Following complete validation and stability studies, the proposed method proved to be sensitive and precise. The limits of detection were 0.07 and 0.08 ng ml(-1) of plasma for mazindol and Met, respectively. The accuracy and recovery were in the ranges 94-102% and 91-102%, respectively, for both compounds. The intra- and inter-assay precisions were less than 7.6 and 9.2%, respectively, for both compounds. The stability of mazindol under different storage conditions, i.e., at room temperature (rt) and 4 degrees C and with freeze-thaw cycles, was also examined. Mazindol was unstable in plasma samples left at rt and 4 degrees C. The method was applied to the determination of mazindol and Met in the plasma of a patient treated for obesity with mazindol. 相似文献