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991.
Yang Shin Park Chang Hee Lee Ji Hoon Kim In Seong Kim Berthold Kiefer Tae Seok Seo Kyeong Ah Kim Cheol Min Park 《Magnetic resonance imaging》2014
Purpose
To assess the usefulness of intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI) for predicting lipiodol uptake in patients with hepatocellular carcinoma (HCC) after transcatheter arterial chemoembolization (TACE).Materials and methods
The institutional review board approved this study. 44 HCC patients underwent IVIM-DWI and Gd-EOB-DTPA-enhanced MRI prior to TACE. Using post-TACE CT as a reference standard, each HCC was classified into either lipiodol good uptake (LGU) or poor uptake (LPU) group. Apparent diffusion coefficient (ADC), true diffusion coefficient (D), perfusion coefficient (D*), and perfusion fraction (f) in HCC were calculated. Arterial enhancement ratio (AER) and IVIM parameters were compared between those two groups using the Mann-Whitney U test.Results
Of the 51 HCCs, 37 (72.5%) were LGU group and 14 (27.5%) were LPU group. AER of HCC was significantly higher in LGU than LPU (0.99 ± 0.54 and 0.67 ± 0.45; P = .034). ADC, D, and f values were not significantly different (P = .073, .059, and .196, respectively) between these two groups. D* was significantly elevated in LGU than LPU (48.10 ± 15.33 and 26.75 ± 9.55; P = .001).Conclusion
Both AER derived from contrast enhanced MRI and D* values derived from IVIM-DWI for HCC were significantly higher in LGU than in LPU. These parameters would be helpful for predicting the lipiodol uptake. 相似文献992.
Jihye Lee Seon Hee Kim Kang-Bong Lee Byoung Koun Min Yeonhee Lee 《Applied Physics A: Materials Science & Processing》2014,115(4):1355-1364
The chalcopyrite semiconductor, Cu(InGa)Se2 (CIGS), is popular as an absorber material for incorporation in high-efficiency photovoltaic devices because it has an appropriate band gap and a high absorption coefficient. To improve the efficiency of solar cells, many research groups have studied the quantitative characterization of the CIGS absorber layers. In this study, a compositional analysis of a CIGS thin film was performed by depth profiling in secondary ion mass spectrometry (SIMS) with MCs+ (where M denotes an element from the CIGS sample) cluster ion detection, and the relative sensitivity factor of the cluster ion was calculated. The emission of MCs+ ions from CIGS absorber elements, such as Cu, In, Ga, and Se, under Cs+ ion bombardment was investigated using time-of-flight SIMS (TOF-SIMS) and magnetic sector SIMS. The detection of MCs+ ions suppressed the matrix effects of varying concentrations of constituent elements of the CIGS thin films. The atomic concentrations of the CIGS absorber layers from the MCs+-SIMS exhibited more accurate quantification compared to those of elemental SIMS and agreed with those of inductively coupled plasma atomic emission spectrometry. Both TOF-SIMS and magnetic sector SIMS depth profiles showed a similar MCs+ distribution for the CIGS thin films. 相似文献
993.
Seong Cheon Kim Mun Sup Lim Young Nam Chun 《Plasma Chemistry and Plasma Processing》2014,34(1):125-143
To decompose carbon dioxide, which is a representative greenhouse gas, a 3-phase gliding arc plasmatron device was designed and manufactured to examine the decomposition of CO2, either alone or in the presence of methane with and without water vapour. The changes in the amount of carbon dioxide feed rate, the methane to carbon dioxide ratio, the steam to carbon dioxide ratio, and the methane to steam ratio were used as the parameters. The carbon dioxide conversion rate, energy decomposition efficiency (EDE), carbon monoxide and hydrogen selectivity, and produced gas concentration were also investigated. The maximum values of the carbon dioxide conversion rate, which is a key indicator of carbon dioxide decomposition, in different cases were compared. The maximum carbon dioxide conversion rate was 12.3 % when pure carbon dioxide was supplied; 34.5 % when methane was injected as a reforming additive; 7.8 % when steam was injected as a reforming additive; and 43 % when methane and steam were injected together. Therefore, this could be explained that the methane-and-steam injection showed the highest carbon dioxide decomposition, showing low EDE as 0.01 L/min W. Furthermore, the plasma produced carbon-black was compared with commercial carbon-black chemicals through Raman spectroscopy, surface area measurement and scanning electron microscopy. It was found that the carbon-black that was produced in this study has the high conductivity and large specific surface area. Our product makes it suitable for special electric materials and secondary battery materials applications. 相似文献
994.
Unique Properties of 2 D Layered Titanate Nanosheets as a Building Block for the Optimization of the Photocatalytic Activity and Photostability of TiO2‐Based Nanohybrids
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Yun Kyung Jo In Young Kim Jayavant L. Gunjakar Jang Mee Lee Nam‐Suk Lee Sang‐Hyup Lee Prof. Seong‐Ju Hwang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(32):10011-10019
In comparison with the hybridization with 0D TiO2 nanoparticle, 2D layered TiO2 nanosheets are much more effective in the improvement of the photocatalytic activity and photostability of semiconducting compounds. The 2D TiO2–Ag3PO4 nanohybrid described in this paper shows a greater decrease in the electron‐hole recombination upon hybridization and a stronger chemical interaction between the components than the 0D homologue. This result confirms the benefits of 2D layered TiO2 nanosheets as a building block for efficient hybrid‐type photocatalyst materials. 相似文献
995.
Kabindra Kafle Rui Shi Christopher M. Lee Ashutosh Mittal Yong Bum Park Ying-Hsuan Sun Sunkyu Park Vincent Chiang Seong H. Kim 《Cellulose (London, England)》2014,21(4):2219-2231
The cellulose microfibril assemblies in secondary cell walls of tension wood and compression wood were studied with vibrational sum frequency generation (SFG) spectroscopy. The tension wood contains the gelatinous layer with highly-crystalline and highly-aligned cellulose microfibrils. The SFG spectral features of tension wood changed depending on the azimuth angle between the polarization of the incident IR beam and the preferential alignment axis of the cellulose microfibrils. The SFG spectra of the compression wood did not show any dependence on the azimuth angle, implying that the overall orientation of cellulose microfibrils in compression wood is not highly aligned. Instead, the decrease of cellulose content in compression wood brought about larger separation between cellulose microfibrils, which was manifested as changes in CH2/OH intensity ratio in SFG spectra. These results implied that SFG spectral features are sensitive to cellulose microfibril alignments and inter-fibrillar separations. 相似文献
996.
Ui-Jin Bae Jae Do Yang Sun-O Ka Jeung-Hyun Koo Seong Ji Woo Young-Rae Lee Hee Chul Yu Baik Hwan Cho Hui-Yuan Zhao Jae-Ha Ryu Sang-Myeong Lee Raok Jeon Byung-Hyun Park 《Experimental & molecular medicine》2014,46(8):e109
Hepatic ischemia/reperfusion (I/R) injury leads to oxidative stress and acute inflammatory responses that cause liver damage and have a considerable impact on the postoperative outcome. Much research has been performed to develop possible protective techniques. We aimed to investigate the efficacy of SPA0355, a synthetic thiourea analog, in an animal model of hepatic I/R injury. Male C57BL/6 mice underwent normothermic partial liver ischemia for 45 min followed by varying periods of reperfusion. The animals were divided into three groups: sham operated, I/R and SPA0355 pretreated. Pretreatment with SPA0355 protected against hepatic I/R injury, as indicated by the decreased levels of serum aminotransferase and reduced parenchymal necrosis and apoptosis. Liver synthetic function was also restored by SPA0355 as reflected by the prolonged prothrombin time. To gain insight into the mechanism involved in this protection, we measured the activity of nuclear factor-κB (NF-κB), which revealed that SPA0355 suppressed the nuclear translocation and DNA binding of NF-κB subunits. Concomitantly, the expression of NF-κB target genes such as IL-1β, IL-6, TNF-α and iNOS was significantly downregulated. Lastly, the liver antioxidant enzymes superoxide dismutase, catalase and glutathione were upregulated by SPA0355 treatment, which correlated with the reduction in serum malondialdehyde. Our results suggest that SPA0355 pretreatment prior to I/R injury could be an effective method to reduce liver damage. 相似文献
997.
Yoon SM Kim SJ Shin HJ Benayad A Choi SJ Kim KK Kim SM Park YJ Kim G Choi JY Lee YH 《Journal of the American Chemical Society》2008,130(8):2610-2616
Chlorine oxoanions with the chlorine atom at different oxidation states were introduced in an attempt to systematically tailor the electronic structures of single-walled carbon nanotubes (SWCNTs). The degree of selective oxidation was controlled systematically by the different oxidation state of the chlorine oxoanion. Selective suppression of the metallic SWCNTs with a minimal effect on the semiconducting SWCNTs was observed at a high oxidation state. The adsorption behavior and charge transfer at a low oxidation state were in contrast to that observed at a high oxidation state. Density functional calculations demonstrated the chemisorption of chloro oxoanions at the low oxidation state and their physisorption at high oxidation states. These results concurred with the experimental observations from X-ray photoelectron spectroscopy. The sheet resistance of the SWCNT film decreased significantly at high oxidation states, which was explained in terms of a p-doping phenomenon that is controlled by the oxidation state. 相似文献
998.
A simple, accurate and robust methodology was established for the direct quantification of ultraviolet (UV)-induced single-strand break (SSB) using oligonucleotide chip. Oligonucleotide chips were fabricated by covalently anchoring the fluorescent-labeled ssDNAs onto silicon dioxide chip surfaces. Assuming that the possibility of more than one UV-induced SSB to be generated in a small oligonucleotide is extremely low, SSB formation was investigated quantifying the endpoint probe density by fluorescence measurement upon UV irradiation. The SSB yields obtained based on the highly sensitive laser-induced fluorometric determination of fluorophore-labeled oligonucleotides were found to coincide well with that predicted from a theoretical extrapolation of the results obtained for plasmid DNAs using conventional agarose gel electrophoresis. The developed method has the potential to serve as a high throughput, sample-thrifty, and time saving tool to realize more realistic, and direct quantification of radiation and chemical-induced strand breaks. It will be especially useful for determining the frequency of SSBs or lesions convertible to SSBs by specific cleaving reagents or enzymes. 相似文献
999.
We investigated the conformational structures of L-phenylglycine in the gas phase by photoionization and double resonance spectroscopy techniques as well as high-level ab initio calculations. The UV-UV and IR-UV double resonance spectroscopy suggested that there exists only one conformer that has a free OH band for the carboxyl group. Rotational contour analysis combined with ab initio calculation indicated that the conformer we detected by resonant two-photon ionization was not one of those found by Sanz et al. in their microwave spectroscopic study [Chem. Eur. J. 12, 2564 (2006)]. Different methods of vaporization along with different expansion and cooling conditions and different detection methods are believed to be the culprit for such intriguing discrepancy. The identical hydrogen bonding structure of our phenylglycine conformer with the most abundant conformer of glycine found in helium droplets and their nearly identical OH frequencies suggest that the skeletal structure of glycine is not significantly altered by phenyl substitution. 相似文献
1000.
This paper describes the applicability of microchip gel electrophoresis using a programmed field strength gradients (MGE-PFSG) method coupled with a polymerase chain reaction (PCR) for the ultra-fast diagnosis of canine T-cell lymphoma. The variable region in the T-cell receptor gamma (TCRgamma) gene from a T-cell lymphoma was used in PCR amplification. The contributions of the various parameters, including the effects of the molecular weight, concentration of the sieving matrix and field strength in MGE, were examined. 0.5% poly (ethyleneoxide) (PEO, M(r) 8000000) was used as the sieving matrix for the ultra-rapid separation of the amplified-PCR products (90 and 130-bp DNA fragments) from the PFSG at an effective length of 20mm in a glass microchip. The PCR products (90 and 130-bp DNA) of the T-cell lymphoma were analyzed within 41.7+/-0.1s, 15.5+/-0.2s and only 7.0+/-0.1s using a low-constant field strength, high-constant field strength and the PFSG, respectively. When 11 clinical samples were analyzed using the MGE-PFSG method, there was a 100% correlation with those obtained using conventional slab gel electrophoresis. The ultra-fast detection and rapid separation capabilities of MGE-PFSG make it an efficient tool for diagnosing T-cell lymphoma in clinical samples with high sensitivity. 相似文献