全文获取类型
收费全文 | 296篇 |
免费 | 5篇 |
专业分类
化学 | 191篇 |
晶体学 | 2篇 |
力学 | 14篇 |
数学 | 42篇 |
物理学 | 52篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2021年 | 8篇 |
2020年 | 6篇 |
2019年 | 4篇 |
2018年 | 2篇 |
2017年 | 4篇 |
2016年 | 10篇 |
2015年 | 8篇 |
2014年 | 15篇 |
2013年 | 25篇 |
2012年 | 32篇 |
2011年 | 30篇 |
2010年 | 17篇 |
2009年 | 13篇 |
2008年 | 22篇 |
2007年 | 15篇 |
2006年 | 11篇 |
2005年 | 18篇 |
2004年 | 9篇 |
2003年 | 5篇 |
2002年 | 13篇 |
2001年 | 4篇 |
2000年 | 7篇 |
1999年 | 4篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1993年 | 1篇 |
1992年 | 5篇 |
1989年 | 1篇 |
1985年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有301条查询结果,搜索用时 15 毫秒
101.
Treatment of unsaturated 1,5-diols 2 with TES-Cl (1.1 equiv), imidazole, and catalytic DMAP in 1:1 CH2Cl2-DMF at -78 degrees C effects selective silylation of the allylic alcohol with >95:5 chemoselectivity when the allylic and homoallylic alcohols are in similar steric environments. 相似文献
102.
103.
104.
Hwang KY Kwon SH Jung SO Lim HK Jung WJ Park CS Kim JH Suh KY Huh N 《Lab on a chip》2011,11(21):3649-3655
We have developed a miniaturized bead-beating device to automate nucleic acids extraction from Gram-positive bacteria for molecular diagnostics. The microfluidic device was fabricated by sandwiching a monolithic flexible polydimethylsiloxane (PDMS) membrane between two glass wafers (i.e., glass-PDMS-glass), which acted as an actuator for bead collision via its pneumatic vibration without additional lysis equipment. The Gram-positive bacteria, S. aureus and methicillin-resistant S. aureus, were captured on surface-modified glass beads from 1 mL of initial sample solution and in situ lyzed by bead-beating operation. Then, 10 μL or 20 μL of bacterial DNA solution was eluted and amplified successfully by real-time PCR. It was found that liquid volume fraction played a crucial role in determining the cell lysis efficiency in a confined chamber by facilitating membrane deflection and bead motion. The miniaturized bead-beating operation disrupted most of S. aureus within 3 min, which turned out to be as efficient as the conventional benchtop vortexing machine or the enzyme-based lysis technique. The effective cell concentration was significantly enhanced with the reduction of initial sample volume by 50 or 100 times. Combination of such analyte enrichment and in situ bead-beating lysis provided an excellent PCR detection sensitivity amounting to ca. 46 CFU even for the Gram-positive bacteria. The proposed bead-beating microdevice is potentially useful as a nucleic acid extraction method toward a PCR-based sample-to-answer system. 相似文献
105.
One-dimensional Cu(OH)(2) or CuO nanostructures were fabricated using inorganic-organic chain assemblies, Cu(C(n)H(2n+1)X)(2)·nH(2)O (X = CO(2), SO(4)) as a lamellar nanoreactor, along with NaOH treatment. The shapes and aspect ratios of the Cu(OH)(2) or CuO nanostructures could be varied by adjusting the hydrophobicity of the lamellar nanoreactors. 相似文献
106.
Yoon KY Kotsmar C Ingram DR Huh C Bryant SL Milner TE Johnston KP 《Langmuir : the ACS journal of surfaces and colloids》2011,27(17):10962-10969
Iron oxide nanoparticles, in the form of sub-100-nm clusters, were synthesized in the presence of poly(acrylic acid) (PAA) or poly(styrene sulfonate-alt-maleic acid) (PSS-alt-MA) to provide electrosteric stabilization. The superparamagnetic nanoclusters were characterized using a superconducting quantum interference device (SQUID), transmission electron microscopy (TEM), dynamic light scattering (DLS), thermogravimetric analysis (TGA), and zeta potential measurements. To anchor the polymer shell on the nanoparticle surface, the polymer was cross-linked for a range of cross-linking densities. For nanoclusters with only 12% (w/w) PSS-alt-MA, electrosteric stabilization was sufficient even in 8 wt % NaCl. For PAA, the cross-linked polymer shell was essentially permanent and did not desorb even upon dilution of the nanoparticles for iron oxide concentrations down to 0.014 wt %. Without cross-linking, over half of the polymer desorbed from the particle surfaces. This general approach of the adsorption of polymer stabilizers onto nanoparticles followed by cross-linking may be utilized for a wide variety of cross-linkable polymers without the need to form covalent bonds between the nanoparticles and polymer stabilizer. Thus, this cross-linking approach is an efficient and inexpensive method of stabilizing nanoparticles for large-scale applications, including the electromagnetic imaging of subsurface reservoirs, even at high salinity. 相似文献
107.
Giyoung Song Suk Man Cho Hee Joon Jung Richard Hahnkee Kim Insung Bae Hyungju Ahn Dr. Du Yeol Ryu Dr. June Huh Dr. Cheolmin Park 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(49):15662-15668
Supramolecular assembly through complementary interaction between molecular subgroups belonging to phase‐separating polymer species offers a great opportunity, not only for constructing nanoscale soft templates reminiscent of conventional block copolymer morphologies, but also for tailoring surface properties by facile removal of one of the structure components by cleaving complementary interactions. Herein we report the fabrication of a novel, organic, nanoporous film through supramolecular assembly of two complementarily, end‐interacting, mono‐end‐functionalized polymers under solvent annealing. The film of end‐functionalized polymer blends under solvent annealing yielded phase‐separated nanodomains that resemble nanoscopically ordered structures of block copolymers, but that are more advantageous due to easily cleavable and exchangeable links between the phase‐separated domains. The removal of one of the components of the precursor structure formed from the end‐functionalized polymers through cleavage of complementary interactions allowed us to fabricate mono‐ or multilayered nanoporous structures in which the chemically useful end‐functionalities of the remnant polymers are rich on the surface of the pores. The resultant, organic, nanoporous films with tailored surface functionality offer a useful platform for various chemical and biological applications. 相似文献
108.
Jung Min KimYun Suk Huh Young-Kyu HanMin Su Cho Hae Jin Kim 《Electrochemistry communications》2012,14(1):32-35
Hierarchical mesoporous γ-MnO2 nanospheres with high crystallinity were prepared by a template-free self-assembly under applied ultrasonic waves, resulting in a solid spherical nanostructure with stacking of nanosized worm-like particles. This approach based on ultrasound exposure reduces the particle size and enhances the crystallinity of γ-MnO2, leading to a large effective area for the active domains and a stable structural arrangement of the active materials. The applicability of γ-MnO2 to high-power lithium batteries is demonstrated, based on improved capacity, excellent rate capability, and stable cyclability, which stem from the outstanding physical properties of the hierarchical mesoporous nanostructure. 相似文献
109.
Jang J Yoo JE Lee JA Lee DR Kim JY Huh YJ Kim DS Park CY Hwang DY Kim HS Kang HC Kim DW 《Experimental & molecular medicine》2012,44(3):202-213
The generation of disease-specific induced pluripotent stem cell (iPSC) lines from patients with incurable diseases is a promising approach for studying disease mechanisms and drug screening. Such innovation enables to obtain autologous cell sources in regenerative medicine. Herein, we report the generation and characterization of iPSCs from fibroblasts of patients with sporadic or familial diseases, including Parkinson's disease (PD), Alzheimer's disease (AD), juvenile-onset, type I diabetes mellitus (JDM), and Duchenne type muscular dystrophy (DMD), as well as from normal human fibroblasts (WT). As an example to modeling disease using disease-specific iPSCs, we also discuss the previously established childhood cerebral adrenoleukodystrophy (CCALD)- and adrenomyeloneuropathy (AMN)-iPSCs by our group. Through DNA fingerprinting analysis, the origins of generated disease-specific iPSC lines were identified. Each iPSC line exhibited an intense alkaline phosphatase activity, expression of pluripotent markers, and the potential to differentiate into all three embryonic germ layers: the ectoderm, endoderm, and mesoderm. Expression of endogenous pluripotent markers and downregulation of retrovirus-delivered transgenes [OCT4 (POU5F1), SOX2, KLF4, and c-MYC] were observed in the generated iPSCs. Collectively, our results demonstrated that disease-specific iPSC lines characteristically resembled hESC lines. Furthermore, we were able to differentiate PD-iPSCs, one of the disease-specific-iPSC lines we generated, into dopaminergic (DA) neurons, the cell type mostly affected by PD. These PD-specific DA neurons along with other examples of cell models derived from disease-specific iPSCs would provide a powerful platform for examining the pathophysiology of relevant diseases at the cellular and molecular levels and for developing new drugs and therapeutic regimens. 相似文献
110.