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941.
A new, highly sensitive chemiluminescence method for measurement of pipecolic acid in various substances such as human serum, cow's milk, beer, and apple juice has been developed. The method is based on reverse-phase ion-pair high performance liquid chromatographic separation and subsequent tris(2,2'-bipyridine)ruthenium(III) chemiluminescence detection. It was confirmed that imino acids show strong chemiluminescence upon mixing with tris(2,2'-bipyridine)ruthenium(III). A calibration graph, based on a standard pipecolic acid solution, was linear over the range 5.0x10(-9)M to 2.0x10(-5)M and the detection limit was 24fmol (signal-to-noise ratio=3). This highly sensitive and selective determination method can be applied to selected samples without purification or pre-concentration procedures. Compared to the previous HPLC methods, the proposed method is easier, more sensitive, and time-saving. 相似文献
942.
An octaethylporphyrin derivative, 1, possessing an exo-five-membered ring fused at the 13- and 15-positions was oxidized by osmium tetroxide to give two isomeric chlorins, 3 and 5, possessing beta,beta'-dihydroxy groups at the A- and C-rings, respectively. Single dehydration of 2,3-dihydroxychlorin 3 gave a mixture of 2- and 3-(1-hydroxyethyl)porphyrins 7, while that of 12,13-dihydroxychlorin 5 resulted in the sole formation of 131-hydroxyporphyrin 9. The latter was modified smoothly to the phytoporphyrin analogue 2, whose molecular skeleton was similar to that of naturally occurring chlorophylls possessing a 131-oxo group fixed on an exo-five-membered ring. 相似文献
943.
Hitoshi Fujimoto Yu Shiotani Albert Y. Tong Takayuki Hama Hirohiko Takuda 《International Journal of Multiphase Flow》2007
The collision dynamics of water droplets impacting onto a solid is studied by means of three-dimensional computer simulations. The Navier–Stokes equations for unsteady, incompressible, viscous fluids in the three-dimensional Cartesian coordinate system are approximated and solved by a finite difference method. The volume-of-fluid (VOF) technique is used to track the free liquid surface. Normal and oblique collisions of droplets with the substrate are simulated at low droplet impact inertia. The effect of impact angle on the deformation behavior of droplets is investigated. The experimental observations and the numerical results are in reasonable agreement. Theoretical aspects of the physics of the collision phenomena are addressed. 相似文献
944.
Yusuke Yasuda Toshiaki Morita Hitoshi Kawaji 《Journal of Thermal Analysis and Calorimetry》2014,115(2):1583-1591
The mechanism of reducing silver(I) oxide particles to silver metals was studied using myristyl alcohol as a reducing agent. The reduction temperature of silver oxide with myristyl alcohol decreased to 150 °C from the temperature of silver oxide in air, 400 °C. The reduction temperature was decreased by myristyl alcohol reacting with silver oxide, which was confirmed by our reaction equation model obtained by gas chromatography determination, pyrolysis gas chromatography–mass spectrometry, and Karl Fischer titration. An endothermic of 153.7 kJ mol?1 in the reduction of silver oxide with myristyl alcohol calculated from the reaction model using Hess’s law was coincident with that obtained experimentally by differential scanning calorimetry measurements. 相似文献
945.
Akihiro Fujii Toshihiro Koura Takashi Yoshimoto Toshiyuki Kawabata Yoshinori Nakamura Keita Hamamichi Hitoshi Kakimoto Yoshimune Yamada Mitsuo Yoshioka Masayoshi Yamamoto Kazuichi Hayakawa 《Journal of Radioanalytical and Nuclear Chemistry》2014,300(2):707-717
A variety of wild mushrooms were collected in a forest on the Noto Peninsula, Japan, to determine the concentration of 137Cs and 40K. The wild mushroom species belong to the orders Agaricales and Aphyllophorales. The concentration of 137Cs varied widely (1.4–4,100 Bq/kg dry weight) in mushrooms growing in soil. On the contrary, 137Cs concentration levels were relatively low (1.9–20 Bq/kg-dry weight) in mushrooms growing on wood. The concentration of 40K varied widely (12–2,400 Bq/kg-dry weight) in contrast with several previous reports that suggest relatively constant 40K levels in mushrooms. Unusually low concentrations of 40K were observed in a few mushroom species that had very hard fruiting bodies with peculiar shapes. The mean and median of 137Cs concentration in the present study were similar to those previously reported for Japanese mushrooms. Among the Agaricales mushrooms, Entolomataceae and Tricholomataceae families growing in soil had the highest concentration of 137Cs. Among the Aphyllophorales mushrooms, Gomphaceae and Ramariaceae families growing in soil also had the highest 137Cs concentrations. The concentrations of 137Cs and stable Cs in mushroom samples were positively correlated. The concentration ratio of 137Cs/Cs differed between Agaricales and Aphyllophorales mushrooms. The average 137Cs/Cs ratio in mushrooms growing in soil was similar to that calculated for the top soil (<5 cm deep) alone because the mycelia of the mushrooms were mainly distributed near the surface of the soil. 相似文献
946.
Koji Hagihara Michiaki Yamasaki Masahito Honnami Hitoshi Izuno Masakazu Tane Takayoshi Nakano 《哲学杂志》2015,95(2):132-157
Formation of curious deformation bands has been reported as one of the deformation mechanisms occurring in an Mg-based long-period stacking ordered (LPSO) phase. The origin of the deformation band is still unknown, and the possibility of the deformation kink band and/or the deformation twin has been discussed. To clarify this, the crystallographic nature of deformation bands formed in the LPSO phase was examined by scanning electron microscope–electron backscatter diffraction (SEM-EBSD) pattern analysis. The results were compared to those of the deformation kink bands formed in hcp-Zn and deformation twins formed in hcp-Mg polycrystals. The deformation bands in the LPSO phase was confirmed not to exhibit a fixed crystal orientation relationship with respect to the matrix, different from the case shown in the deformation twin. Instead, the deformation band in the LPSO phase showed three arbitrariness on its crystallographic nature: an ambiguous crystal rotation axis that varied on the [0 0 0 1] zone axis from band to band; an arbitral crystal rotation angle that was not fixed and showed relatively wide distributions; and a variation in crystal rotation angle depending on the position even within a deformation band boundary itself. These features were coincident with those observed in the deformation bands formed in Zn polycrystals, suggesting that the formed deformation bands in LPSO phase crystals are predominantly deformation kink bands. 相似文献
947.
948.
Maiko Kusano Kei Zaitsu Hiroshi Nakayama Junichi Nakajima Kazuaki Hisatsune Takako Moriyasu Shuntaro Matsuta Munehiro Katagi Hitoshi Tsuchihashi Akira Ishii 《Journal of mass spectrometry : JMS》2015,50(3):586-591
Like many new designer drugs of abuse, synthetic cannabinoids (SC) have structural or positional isomers which may or may not all be regulated under law. Differences in acute toxicity may exist between isomers which impose further burden in the fields of forensic toxicology, medicine and legislation. Isomer differentiation therefore becomes crucial from these standpoints as new designer drugs continuously emerge with just minor positional modifications to their preexisting analogs. The aim of this study was to differentiate the positional isomers of JWH‐081. Purchased standard compounds of JWH‐081 and its positional isomers were analyzed by gas chromatography‐electron ionization‐mass spectrometry (GC‐EI‐MS) first in scan mode to investigate those isomers who could be differentiated by EI scan spectra. Isomers with identical or near‐identical EI spectra were further subjected to GC‐tandem mass spectrometry (MS/MS) analysis with appropriate precursor ions. EI scan was able to distinguish 3 of the 7 isomers: 2‐methoxy, 7‐methoxy and 8‐methoxy. The remaining isomers exhibited near‐identical spectra; hence, MS/MS was performed by selecting m/z 185 and 157 as precursor ions. 3‐Methoxy and 5‐methoxy isomers produced characteristic product ions that enabled the differentiation between them. Product ion spectrum of 6‐methoxy isomer resembled that of JWH‐081; however, the relative ion intensities were clearly different from one another. The combination of EI scan and MS/MS allowed for the regioisomeric differentiation of the targeted compounds in this study. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
949.
Huong Vu Thi Yoshikawa Hiroyuki Hoa Le Quynh Toake Hitoshi Shibata Toshiyuki Tamiya Eiichi 《Journal of Solid State Electrochemistry》2016,20(5):1481-1488
Journal of Solid State Electrochemistry - In this research, we conducted a comprehensive interrogation of a direct fucose fuel cell to maximise the electric power and demonstrated the potential for... 相似文献
950.
Yuki Hirai Hitoshi Tamiaki Shigenori Kashimura Yoshitaka Saga 《Photochemistry and photobiology》2009,85(5):1140-1146
Demetalation kinetics of bacteriochlorophylls (BChls) c, d and e from green sulfur photosynthetic bacteria were studied under weakly acidic conditions. Demetalation rate constants of BChl e possessing a formyl group at the 7-position were significantly smaller than those of BChls c and d , which had a methyl group at this position. The activation energy of demetalation of 31 R -8,12-diethyl([E,E])-BChl e was 1.5-times larger than that of 31 R -[E,E]-BChl c . 15 N-labeled 31 R -[E,E]-BChls c and e were purified from cells of green sulfur bacteria grown in a medium containing 15 NH4 Cl, and their 15 N NMR spectra were measured. The chemical shifts of N21 , N22 and N23 atoms of 31 R -[E,E]-BChl e were lower-field shifted than those of 31 R -[E,E]-BChl c , respectively, and especially the difference in chemical shifts of N22 was significantly large. These results suggest that the electron-withdrawing formyl group at the 7-position of BChl e affected an electronic state of the chlorin macrocycle and caused BChl e to be more tolerant for removal of the central magnesium compared with BChls c and d . 相似文献