全文获取类型
收费全文 | 507篇 |
免费 | 12篇 |
国内免费 | 1篇 |
专业分类
化学 | 329篇 |
晶体学 | 4篇 |
力学 | 15篇 |
数学 | 74篇 |
物理学 | 98篇 |
出版年
2023年 | 8篇 |
2022年 | 14篇 |
2021年 | 11篇 |
2020年 | 11篇 |
2019年 | 17篇 |
2018年 | 8篇 |
2017年 | 6篇 |
2016年 | 20篇 |
2015年 | 20篇 |
2014年 | 28篇 |
2013年 | 41篇 |
2012年 | 30篇 |
2011年 | 42篇 |
2010年 | 25篇 |
2009年 | 23篇 |
2008年 | 19篇 |
2007年 | 24篇 |
2006年 | 23篇 |
2005年 | 29篇 |
2004年 | 24篇 |
2003年 | 19篇 |
2002年 | 12篇 |
2001年 | 15篇 |
2000年 | 9篇 |
1999年 | 5篇 |
1998年 | 6篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 5篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1973年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有520条查询结果,搜索用时 15 毫秒
41.
42.
43.
Young-Kwon Park Hyung Won Lee Jong-Ki Jeon Seung-Soo Kim Changkook Ryu Ji Man Kim Ho-Jeong Chae Kwang-Eun Jeong 《Research on Chemical Intermediates》2011,37(9):1283-1291
The catalytic cracking of oil fractions separated from summer food waste leachate was investigated over BEA zeolite and Al-SBA-15 catalysts. In this study, a mixture of food waste oil fractions and catalyst was directly introduced to pyrolysis gas chromatography/mass spectrometry (Py-GC/MS), with the resulting vapor phase products being simultaneously analyzed. Various acid compounds, including oleic acid, produced by the non-catalytic pyrolysis of food waste leachate were reformed into valuable compounds, such as oxygenates, hydrocarbons, and aromatics. The BEA zeolite catalyst showed higher selectivity for hydrocarbon compounds, especially aromatics, within the gasoline range due to its superior cracking ability originating from its highly acidic sites. Conversely, the cracking performance of the Al-SBA-15 catalyst, possessing mild acidic sites, was lower than that of the BEA zeolite. Increasing the amount of Al-SBA-15 catalyst enhanced the cracking activity and resulted in higher selectivity for hydrocarbons. 相似文献
44.
A fast and matrix assisted laser desorption/ionization-mass spectrometry (MALDI-MS) compatible protein staining method in one- and two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (1- and 2-D SDS-PAGE) is described. It is based on the counterion dye staining method that employs oppositely charged two dyes, zincon (ZC) and ethyl violet (EV) to form an ion-pair complex. The protocol, including fixing, staining and quick washing steps, can be completed in 1-1.5 h depending upon gel thickness. It has a sensitivity of 4-8 ng, comparable to that of colloidal Coomassie Brilliant Blue G (CBBG) staining with phosphoric acid in the staining solution. The counterion dye stain does not induce protein modifications that complicate interpretation of peptide mapping data from MS. Considering the speed, sensitivity and compatibility with MS, the counterion dye stain may be more practical than any other dye-based protein stains for routine proteomic researches. 相似文献
45.
46.
Eun-Heui Jin Seung-Cheol Shim Hwan-Gyu Kim Soo-Cheon Chae Hun-Taeg Chung 《Experimental & molecular medicine》2009,41(5):354-361
To select candidate genes, we attempted to comparative analysis of protein levels between rheumatoid arthritis (RA) patients and healthy controls by two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption ionization mass spectrometry (MALDI-TOF-MS). We identified 17 proteins that showed up- or down-regulated spots in RA patients. We found that coactosin-like1 (COTL1) were highly expressed in RA patients compared with healthy controls. We performed a case-control study to determine whether the COTL1 gene polymorphisms were associated with RA and systemic lupus erythematosus (SLE). The genotype frequency of c.-1124G>T and the allelic frequency of c.484G>A in RA patients, and the genotype frequency of c.484G>A in SLE patients were significantly different from healthy controls (P = 0.009, 0.027, and 0.025, respectively). We also investigated the correlation with the levels of rheumatoid factor (RF) and anti-cyclic citrullinated peptide (CCP) antibody in RA patients, and anti-nuclear antibodies (ANA) in SLE patients. The c.484G>A polymorphism in RA patients has significant association with the levels of anti-CCP antibody (P = 0.03). Our findings demonstrated that c.-1124G>T and c.484G>A polymorphisms of the COTL1 gene might be associated with the genetic susceptibility of autoimmune disorders. 相似文献
47.
Jae Hyeung Park Hyun Woo Lee Dong Keun Chae Weontae Oh Jae Deuk Yun Yulin Deng Jeong Hyun Yeum 《Colloid and polymer science》2009,287(8):943-950
Submicron fibers of the composite of poly(vinyl alcohol) (PVA), chitosan oligosaccharide [COS, (1→4)2-amino-2-deoxy-β-d-glucose], and montmorillonite clay (MMT) were prepared using electrospinning method with aqueous solutions. Scanning electron
microscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), thermal gravimetric analyzer, and tensile strength
testing machine (Zwick) were utilized to characterize the PVA/COS/MMT nanofiber mats morphology and properties. The PVA/COS
ratio and MMT concentration play important roles in nanofiber mat properties. XRD and TEM data demonstrated that exfoliated
MMT layers were well-distributed within nanofiber. It was also found that the mechanical property and thermal stability were
increased with COS and MMT contents. 相似文献
48.
Yeon-Su Chae Seung-Hee Lee Ye-Hwang Cheang Nuribalhae Lee Young-Soo Rim Deok-Jin Jang Bong-Kiun Kaang 《Experimental & molecular medicine》2010,42(1):30-37
The cytoplasmic polyadenylation element (CPE)-binding protein (CPEB) binds to CPE containing mRNAs on their 3'' untranslated regions (3''UTRs). This RNA binding protein comes out many important tasks, especially in learning and memory, by modifying the translational efficiency of target mRNAs via poly (A) tailing. Overexpressed CPEB has been reported to induce the formation of stress granules (SGs), a sort of RNA granule in mammalian cell lines. RNA granule is considered to be a potentially important factor in learning and memory. However, there is no study about RNA granule in Aplysia. To examine whether an Aplysia CPEB, ApCPEB1, forms RNA granules, we overexpressed ApCPEB1-EGFP in Aplysia sensory neurons. Consistent with the localization of mammalian CPEB, overexpressed ApCPEB1 formed granular structures, and was colocalized with RNAs and another RNA binding protein, ApCPEB, showing that ApCPEB1 positive granules are RNA-protein complexes. In addition, ApCPEB1 has a high turnover rate in RNA granules which were mobile structures. Thus, our results indicate that overexpressed ApCPEB1 is incorporated into RNA granule which is a dynamic structure in Aplysia sensory neuron. We propose that ApCPEB1 granule might modulate translation, as other RNA granules do, and furthermore, influence memory. 相似文献
49.
Jin Young Park Hong Chae Jung G. Seeta Rama Raju Byung Kee Moon Jung Hyun Jeong Jung Hwan Kim 《Solid State Sciences》2010,12(5):719-724
A series of Eu3+ ions co-doped (Gd0.9Y0.1)3Al5O12:Bi3+, Tb3+ (GYAG) phosphors have been synthesized by means of solvothermal reaction method. The XRD pattern of GYAG phosphor sintered at 1500 °C confirms their garnet phase. The luminescence properties of these phosphors have been explored by analyzing their excitation and emission spectra along with their decay curves. The excitation spectra of the GYAG:Bi3+, Tb3+, Eu3+ phosphors consists of broad bands in the shorter wavelength region due to 4f8 → 4f75d1 transition of Tb3+ ions overlapped with 6s2 → 6s16p1 (1S0 → 3P1) transition of Bi3+ ions and the charge transfer band of Eu3+–O2?. The present phosphors exhibit green and red colors due to 5D4 → 7F5 transition of Tb3+ ions and 5D0 → 7F1 transition of Eu3+ ions, respectively. The emission was shifted from green to red color by co-doping with Eu3+ ions, which indicate that the energy transfer probability from Tb3+ to Eu3+ ions are dependent strongly on the concentration of Eu3+ ions. 相似文献
50.
Effects of Water Vapor and Ammonia on SO2 Removal from Flue Gases Using Pulsed Corona Discharge 总被引:3,自引:0,他引:3
Yimin Zhu Chae J. O. Kim K. Y. Kim K. O. Park Y. K. 《Plasma Chemistry and Plasma Processing》2002,22(1):187-195
Plasma Chemistry and Plasma Processing - In the study of SO2 removal using pulsed corona discharge, there exists a serious confusion, that is, which kind of reactions, the thermal chemical... 相似文献