全文获取类型
收费全文 | 1898篇 |
免费 | 84篇 |
国内免费 | 3篇 |
专业分类
化学 | 1414篇 |
晶体学 | 23篇 |
力学 | 41篇 |
综合类 | 1篇 |
数学 | 87篇 |
物理学 | 419篇 |
出版年
2023年 | 15篇 |
2022年 | 7篇 |
2021年 | 26篇 |
2020年 | 49篇 |
2019年 | 55篇 |
2018年 | 27篇 |
2017年 | 26篇 |
2016年 | 60篇 |
2015年 | 54篇 |
2014年 | 90篇 |
2013年 | 134篇 |
2012年 | 164篇 |
2011年 | 183篇 |
2010年 | 111篇 |
2009年 | 97篇 |
2008年 | 152篇 |
2007年 | 148篇 |
2006年 | 124篇 |
2005年 | 90篇 |
2004年 | 83篇 |
2003年 | 50篇 |
2002年 | 51篇 |
2001年 | 24篇 |
2000年 | 17篇 |
1999年 | 7篇 |
1998年 | 18篇 |
1997年 | 8篇 |
1996年 | 17篇 |
1995年 | 10篇 |
1994年 | 15篇 |
1993年 | 11篇 |
1992年 | 13篇 |
1991年 | 13篇 |
1990年 | 4篇 |
1989年 | 6篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1971年 | 2篇 |
1968年 | 1篇 |
排序方式: 共有1985条查询结果,搜索用时 78 毫秒
1.
2.
Lee Chang Hwa Kim Tack-Jin Yoon Dalsung Jang Junhyuk Kim Gha-Young Lee Sung-Jai 《Journal of Radioanalytical and Nuclear Chemistry》2019,322(2):331-336
Journal of Radioanalytical and Nuclear Chemistry - U chlorination is demonstrated using electrochemical and chemical reactions with ZnCl2 in LiCl–KCl molten salts. Voltammetric studies... 相似文献
3.
4.
Dileep K. Singh Suzi Kim Jeong Hwa Lee Na Keum Lee Jinwoo Kim Jeeyeon Lee Ikyon Kim 《Journal of heterocyclic chemistry》2020,57(8):3018-3028
A highly fluorescent indolizino[1,2-c]quinoline with a substituent at the C6 position was designed and synthesized as a new indolizine-quinoline hybrid structure via a tetracyclic lactam. Various (hetero)aryl groups were introduced at the C6 site of this basic skeleton to display intriguing photophysical properties. 相似文献
5.
Nam Joo Lee Dongseok Kim Kwangho Yoo Yeji Yu Byeong-Su Kim Jeung Gon Kim 《Journal of polymer science. Part A, Polymer chemistry》2020,58(22):3237-3244
A simple and divergent synthetic strategy of bottlebrush polymers (BBPs) is presented, consisting of postpolymerization modification of a macromonomer and grafting-through polymerization. Beginning with a single macromonomer, its direct modification could build a library of macromonomers with an identical chain length, thus guaranteeing the precision in the synthesis of BBPs. In this study, a newly designed norbornenyl-terminated poly(methyl acrylate) (NB-PMA) is proposed as a chemically robust template. Ti-mediated transesterification of NB-PMA successfully produces structurally diverse polyacrylates while maintaining the terminal norbornenyl group intact. All macromonomers obtained from transesterification possess a good grafting-through ring-opening metathesis polymerization reactivity, furnishing homo, random, and block BBPs in a controllable manner. Moreover, atomic force microscopy analysis supports the controlled side-chain length distribution in the resulting BBPs. 相似文献
6.
Young Eun Jeun Joon Ho Park Joo Yeon Kim Prof. Hyun S. Ahn 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(18):4039-4043
Mixed-metal oxyhydroxides—especially those of Ni and Fe—are one of the most active classes of materials known for catalyzing the oxygen evolution reaction (OER). Here, nanoparticulate mixed metal oxyhydroxides (of Ni, Fe, and Co) were prepared on an electrode surface by electrochemical reaction of a precursor solution encapsulated in aqueous nanodroplets (AnDs), with each of the droplets containing 10 s of attoliters of fluid. Electrode reactions and synthesis can be monitored in situ by electrochemistry as single AnD stochastically lands and interacts with the working electrode. Resultant metal oxyhydroxide nanoparticles can be size and composition controlled precisely by modulating the precursor solution stored in the AnD. Nanoparticulate metal oxyhydroxides were implemented as catalysts for the OER and exhibited superior catalysis compared to their thin-film counterparts, demonstrating a hundred-thousand-fold enhancement in atom efficiency at comparable turnover rates. 相似文献
7.
8.
Sungmi Park Jeong-Kook Kim Chang Joo Oh Seung Hee Choi Jae-Han Jeon In-Kyu Lee 《Experimental & molecular medicine》2015,47(3):e145
Scoparone, which is a major constituent of Artemisia capillaries, has been identified as an anticoagulant, hypolipidemic, vasorelaxant, anti-oxidant and anti-inflammatory drug, and it is used for the traditional treatment of neonatal jaundice. Therefore, we hypothesized that scoparone could suppress the proliferation of VSMCs by interfering with STAT3 signaling. We found that the proliferation of these cells was significantly attenuated by scoparone in a dose-dependent manner. Scoparone markedly reduced the serum-stimulated accumulation of cells in the S phase and concomitantly increased the proportion of cells in the G0/G1 phase, which was consistent with the reduced expression of cyclin D1, phosphorylated Rb and survivin in the VSMCs. Cell adhesion markers, such as MCP-1 and ICAM-1, were significantly reduced by scoparone. Interestingly, this compound attenuated the increase in cyclin D promoter activity by inhibiting the activities of both the WT and active forms of STAT3. Similarly, the expression of a cell proliferation marker induced by PDGF was decreased by scoparone with no change in the phosphorylation of JAK2 or Src. On the basis of the immunofluorescence staining results, STAT3 proteins phosphorylated by PDGF were predominantly localized to the nucleus and were markedly reduced in the scoparone-treated cells. In summary, scoparone blocks the accumulation of STAT3 transported from the cytosol to the nucleus, leading to the suppression of VSMC proliferation through G1 phase arrest and the inhibition of Rb phosphorylation. This activity occurs independent of the form of STAT3 and upstream of kinases, such as Jak and Src, which are correlated with abnormal vascular remodeling due to the presence of an excess of growth factors following vascular injury. These data provide convincing evidence that scoparone may be a new preventative agent for the treatment of cardiovascular diseases. 相似文献
9.
Nishat Arshi Junqing Lu Yun Kon Joo Jae Hong Yoon Bon Heun Koo 《Surface and interface analysis : SIA》2015,47(1):154-160
Nanocrystalline tantalum nitride (TaN) thin films have been deposited by reactive direct current magnetron sputtering technique on Si/SiO2 (100) substrate with nitrogen flow rate ranging from 0, 3, 5, 7, 9 to 11 standard cubic centimeter per minute (sccm). Structural properties, surface morphology, chemical composition and and resistivity of the TaN films were investigated by X‐ray diffraction (XRD), field emission scanning electron microscopy, X‐ray photoemission spectroscopy (XPS) and four‐point probe measurements, respectively. In the XRD spectra, a classical formation sequence of tantalum nitride phases in the order of Ta‐Ta2N‐TaN‐Ta4N5 and decreasing amount of metallic Ta were observed with increasing nitrogen flow. The electrical resistivity of the TaN film was found to increase with increasing N/Ta ratio as a result of the increased electron scattering from interstitial N atoms. In the XPS analysis, two groups of Ta4f doublets relating to different TaN phases were observed in the core level spectra of TaN films. No strong coupling was observed between the Ta4f doublets and the Ta4p and the N1s groups. The appropriate nitrogen flow was believed to be helpful in the bonding and formation of stoichiometric TaN. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
10.
Anchoring Mechanism of ZnO Nanoparticles on Graphitic Carbon Nanofiber Surfaces through a Modified Co‐Precipitation Method to Improve Interfacial Contact and Photocatalytic Performance 下载免费PDF全文
Dr. Gowra Raghupathy Dillip Dr. Arghya Narayan Banerjee Dr. Veettikunnu Chandran Anitha Dr. Sang Woo Joo Dr. Bong Ki Min Dr. Sandesh Y. Sawant Dr. Moo Hwan Cho 《Chemphyschem》2015,16(15):3214-3232
A facile three‐step co‐precipitation method is developed to synthesize graphitic carbon nanofibers (CNFs) decorated with ZnO nanoparticles (NPs). By interchanging intermediate steps of the reaction processes, two kinds of nanohybrids are fabricated with stark morphological and physicochemical differences. The morphologies differ because of the different chemical environments of the NP/nanocluster formation. The hybrid with larger and non‐uniform ZnO nanocluster size is formed in liquid phase and resulted in considerable interfacial defects that deteriorate the charge‐transfer properties. The hybrid with smaller and uniform ZnO NPs was formed in a dry solid phase and produced near‐defect‐free interfaces, leading to efficient charge transfer for superior photocatalytic performance. The results broaden the understanding of the anchoring/bonding mechanism in ZnO/CNF hybrid formation and may facilitate further development of more effective exfoliation strategies for the preparation of high‐performance composites/hybrids. 相似文献