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141.
并二苯环纳米分子桥的电子传导特性 总被引:1,自引:0,他引:1
利用基于GreenFunction的Tight binding方法,对由平面苯分子环耦合成的二端子纳米分子桥进行了理论计算和数值模拟,得出了入射电子通过纳米分子桥传输到不对称端点的电子传输概率,揭示出传导电子与分子轨道共振时传输峰值的出现和电子传输振荡的物理机制.利用Fisher Lee关系式和电子流密度理论,在传输概率出现峰值的四个能量点E=±0.68和E=±1.38处计算了分子桥内的电子流分布,给出了这些能量点处环电流生成的物理解释和键电流的最大值,并且给出了分子内电流分布的图形模拟结果. 相似文献
142.
We investigated spatial frequency tuning of the mechanisms for stereoscopic depth perception, using a masking technique, and compared these tunings with those for luminance pattern detection. Observers discriminated depth direction in random-dot stereograms with various contrasts of a masking pattern, which was dichoptic stimulus of uncorrelated random dots. The strength of masking effect as a function of spatial frequency (i.e., masking function) was measured: masking function approximates the spatial frequency tuning of the mechanism that detects the depth in the test pattern. The masking functions for stereoscopic depth were found to be similar to either of the three of the six spatial frequency channels proposed by Wilson and Gelb (1984) for the detection of luminance patterns. 相似文献
143.
Toshihide Tsuda Akira Babazono Takanori Ogawa Hirohisa Hamada Yoshio Mino Hideyasu Aoyama Norio Kurumatani Tsuyoshi Nagira Nobuyuki Hotta Masazumi Harada Shigemi Inomata 《应用有机金属化学》1992,6(4):309-322
Human being have been using inorganic arsenic for a long time. Many reports on arsenic poisoning have been published: eg case reports, examination reports, post mortem reports, and epidemiological studies. Several aspects and features of arsenic poisoning are discussed in this report. Methods of inferring arsenic-related disease, disease classification according to acute or chronic criteria, exposure route, interaction, confounding factors, and the oxidation state of arsenic are all discussed. The effects of arsenic are classified into skin, respiratory system, gastrointestinal tract, liver, cardiovascular system, nervous system, and bone marrow effects. Carcinogenicity is an important chronic effect of arsenic poisoning, so special attention is paid to it in this review. In Japan, there have been many incidents of arsenic poisoning. In this review, we often use data from these cases, such as the Morinaga powdered-milk poisoning case, the Ube soy-sauce poisoning case, the Toroku mine incident, and the Nakajo well-water poisoning case. We emphasize here the necessity of planning follow-up studies and total health care for patients exposed to arsenic. 相似文献
144.
In order to determine trace levels of rhenium in plant samples by ICP-MS, a pretreatment method was developed. Ten radish samples (Raphanus sativus L.) grown in solution culture containing 184ReO4
- were used. The samples were separated into three parts (leaves, fleshy root and fine roots), then each sample was oven-dried at 60 °C. The Re loss ratios in the samples after incineration at 450 °C for 3 hours and acid leaching at 90 °C for 3 hours were compared. There was no difference of recoveries among the sample parts, and throughout the procedure, almost 100% Re was recovered from the samples. 相似文献
145.
Mori K Ishibashi Y Matsuda H Ito S Nagasawa Y Nakagawa H Uchida K Yokojima S Nakamura S Irie M Miyasaka H 《Journal of the American Chemical Society》2011,133(8):2621-2625
One-color control of colorization/decolorization reactions of diarylethene molecules was attained by using nonresonant high-order multiphoton absorption processes with a near-infrared (NIR) femtosecond laser pulse at 1.28 μm with 35 fs full width at half-maximum (fwhm). The intensity of a rather weak laser pulse (<1 nJ/pulse) can induce the simultaneous three-photon absorption leading to the colorization, while much weaker intensity induces two-photon absorption resulting in the decolorization. The spatial patterning concomitant with higher-order multiphoton absorption processes was also demonstrated. 相似文献
146.
This article describes an analytical method for the separation, preconcentration and determination of 232Th in seawater samples at sub-ng/L levels using a NOBIAS CHELATE PA1 resin and a sector field (SF) inductively coupled plasma mass spectrometer (ICP-MS). The resin showed excellent adsorption of 232Th at a low pH of 2.4 ± 0.4 in a relatively small volume (200 mL) of seawater. 232Th adsorbed on the resin was easily eluted using 5 mL of 0.8 M HNO3. An enrichment factor of 40 was achieved for 232Th analysis. Ethylenediamine-tetraacetic acid disodium salt dehydrate (EDTA) was used to investigate the effect of 232Th-binding organic ligand on the retention of 232Th on the chelating resin. Results obtained using acidified samples (pH of 2.4 ± 0.4) showed EDTA had no significant effect on 232Th recovery, indicating that at this low pH, 232Th was dissociated from the 232Th-binding organic ligand and quantitatively retained on the NOBIAS CHELATE PA1 resin. The developed analytical method was characterized by a separation and preconcentration taking approximately 4 h and a low detection limit of 0.0038 ng/L for 232Th, and was successfully applied to the determination of 232Th in seawater samples collected from coastal areas, Japan. 相似文献
147.
Adsorption and photodegradation properties of anionic dyes by layered double hydroxides 总被引:1,自引:0,他引:1
Kazuya Morimoto Nobuo Iyi Jinhua Ye Hirohisa Yamada 《Journal of Physics and Chemistry of Solids》2011,72(9):1037-1045
The adsorption and photodegradation behavior of methyl orange (MO) and fast green (FG) over ZnAl- and MgAl-based layered double hydroxide (LDH) adsorbents have been examined. ZnAl-LDHs were prepared with Zn/Al ratios of 2 to 4 by co-precipitation at pH 8. The ZnAl-LDHs and a commercial MgAl-LDH with a Mg/Al ratio of 3 were evaluated for their ability to adsorb MO and FG and for the photodegradation behavior of these dyes under UV irradiation. Structure analysis of the LDH-dyes-adsorbed complexes revealed that the adsorption produced two types of structures, an intercalation complex for MO and a surface-adsorbed complex for FG. The maximum adsorption of MO on the LDHs was significantly higher (more than tenfold) than FG. Results indicated the adsorption isotherms for the retention of both dyes by ZnAl- and MgAl-LDHs could be fitted to a Freundlich equation, showing a higher affinity for dyes on MgAl-LDH compared to those on ZnAl-LDH. The catalytic degradation ability of dye-LDH complex solid films on a quartz plate was superior to pure dye films under UV irradiation. The FG non-intercalated LDH complexes showed much faster photodegradation under UV irradiation than the MO-intercalated LDH complexes, which pointed to the important role of the LDH materials containing sensitized dyes in enhancing the generation of labile hydroxyl ions from the hydrophilic LDH surface. 相似文献
148.
149.
150.
Hajime Seito Tatsuya Ichikawa Hiroaki Hanaya Yoshishige Sato Hirohisa Kaneko Yasuyuki Haruyama Hiroshi Watanabe Takuji Kojima 《Radiation Physics and Chemistry》2009,78(11):961-965
Characteristics of clear PMMA dosimeter (Radix W) were studied for electron irradiation and compared with the response for gamma irradiation. The dose–response curves were nearly linear up to 30 kGy and become sublinear at higher doses. The radiation-induced absorbance was reduced with 6% within 4 h after irradiation. Dose comparisons were performed for 2, 3, 4 and 5 MeV electron irradiation using cellulose triacetate dosimeter (CTA) (FTR-125) and Radix W dosimeters which were independently calibrated for 2 MeV electrons and 60Co gamma-rays using calorimeter and ionizing chamber, respectively. The doses estimated by CTA and Radix W were different by about 20%. The magnitude of this difference was, however, independent of electron energy. 相似文献