全文获取类型
收费全文 | 719篇 |
免费 | 37篇 |
国内免费 | 6篇 |
专业分类
化学 | 557篇 |
晶体学 | 3篇 |
力学 | 11篇 |
数学 | 84篇 |
物理学 | 107篇 |
出版年
2023年 | 2篇 |
2022年 | 8篇 |
2021年 | 11篇 |
2020年 | 7篇 |
2019年 | 12篇 |
2018年 | 12篇 |
2017年 | 10篇 |
2016年 | 21篇 |
2015年 | 17篇 |
2014年 | 21篇 |
2013年 | 36篇 |
2012年 | 52篇 |
2011年 | 78篇 |
2010年 | 43篇 |
2009年 | 37篇 |
2008年 | 67篇 |
2007年 | 37篇 |
2006年 | 41篇 |
2005年 | 49篇 |
2004年 | 40篇 |
2003年 | 34篇 |
2002年 | 30篇 |
2001年 | 15篇 |
2000年 | 9篇 |
1999年 | 2篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1996年 | 5篇 |
1995年 | 5篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1986年 | 1篇 |
1985年 | 8篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 4篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1972年 | 1篇 |
1967年 | 1篇 |
1879年 | 1篇 |
排序方式: 共有762条查询结果,搜索用时 15 毫秒
31.
32.
Younseok Choo 《Journal of Optimization Theory and Applications》2014,161(2):553-556
An approach based on the Rouché theorem was introduced in the literature to compute the optimum radius for robust stability of Schur polynomials. Later an attempt was made to improve the result, but it was shown to be incorrect. The purpose of this note is to show that an improved optimum radius still can be obtained by modifying the proposed method. The result of this note can be easily extended to the multidimensional cases. 相似文献
33.
34.
Yae Eun Chong Manting Chiang Kiran Deshpande Simon Haroutounian Leonid Kagan Jong Bong Lee 《Biomedical chromatography : BMC》2019,33(11)
Ondansetron, a widely used antiemetic agent, is a P‐glycoprotein (P‐gp) substrate and therefore expression of P‐gp at the blood–brain barrier limits its distribution to the central nervous system (CNS), which was observed to be reversed by coadministration with P‐gp inhibitors. Tariquidar is a potent and selective third‐generation P‐gp inhibitor, and coadministration with ondansetron has shown improved ondansetron distribution to the CNS. There is currently no reported bioanalytical method for simultaneously quantifying ondansetron with a third‐generation P‐gp inhibitor. Therefore, we aimed to develop and validate a method for ondansetron and tariquidar in rat and human plasma samples. A full validation was performed for both ondansetron and tariquidar, and sample stability was tested under various storage conditions. To demonstrate its utility, the method was applied to a preclinical pharmacokinetic study following coadministration of ondansetron and tariquidar in rats. The presented method will be valuable in pharmacokinetic studies of ondansetron and tariquidar in which simultaneous determination may be required. In addition, this is the first report of a bioanalytical method validated for quantification of tariquidar in plasma samples. 相似文献
35.
Eun‐Ju Ha Bong‐Soo Kim Eun‐Kyoung Park Ki‐Won Song Sun‐Gu Lee Seong Soo A. An Hyun‐jong Paik 《先进技术聚合物》2013,24(1):75-80
Ni2+‐complexed poly(2‐acetamidoacrylic acid) (PAAA) hydrogel beads were developed for the site‐specific reversible immobilization and purification of the histidine‐tagged green fluorescent protein (His‐tagged GFP). PAAA hydrogel beads were prepared by photopolymerization, and significantly improved mechanical properties of PAAA hydrogel beads were observed in comparison with PAAA hydrogel from our previous study. Confocal laser scanning microscopy was used to determine the binding of His‐tagged GFP to the hydrogel beads in three‐dimensional space. Photoluminescence spectroscopy revealed 89% of binding efficiency of His‐tagged GFP to the Ni2+‐PAAA hydrogel beads, 51% of yielding recovery. The maximum binding capacity of His‐tagged GFP was estimated to be 0.45 µg/mg of Ni2+‐PAAA hydrogel beads. The recombinant His‐tagged GFP from the soluble fraction of E. coli BL21(DE3) cell lysates was purified with Ni2+‐PAAA hydrogel beads. The major advantage of the Ni2+‐PAAA hydrogel beads system was simple preparation procedures of producing the matrix, because PAAA hydrogel beads had relatively enhanced mechanical strength than soft hydrogels. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
36.
Jong Min Lee Ji‐eun Kim Jayant Borana Bong Hyun Chung Bong Geun Chung 《Electrophoresis》2013,34(13):1931-1938
We developed the dual‐micropillar‐based microfluidic platform to direct embryonic stem (ES) cell fate. 4 × 4 dual‐micropillar‐based microfluidic platform consisted of 16 circular‐shaped outer micropillars and 8 saddle‐shaped inner micropillars in which single ES cells were cultured. We hypothesized that dual‐micropillar arrays would play an important role in controlling the shear stress and cell docking. Circular‐shaped outer micropillars minimized the shear stress, whereas saddle‐shaped inner micropillars allowed for docking of individual ES cells. We observed the effect of saddle‐shaped inner micropillars on cell docking in response to hydrodynamic resistance. We also demonstrated that ES cells cultured for 6 days within the dual‐micropillar‐based microfluidic platform differentiated into neural‐like cells. Therefore, this dual‐micropillar‐based microfluidic platform could be a potentially powerful method for screening of lineage commitments of single ES cells. 相似文献
37.
Christopher J. G. Plummer Caleb K. C. Choo Carole I. R. Boissard Pierre-Etienne Bourban Jan-Anders E. Månson 《Colloid and polymer science》2013,291(9):2203-2211
Optical microscopy and transmission electron microscopy have been used to investigate the morphology of polylactide (PLA)/microfibrillated cellulose (MFC) composites prepared by: compression molding of wet-comingled MFC and PLA latex or powder, twin-screw extrusion of the wet-comingled compounds, and solvent mixing of PLA with MFC or acetylated MFC. Compression molding of wet-comingled MFC and PLA latex or powder compounds resulted in a cellular MFC network, whereas solvent-cast films showed a more uniform dispersion of MFC fibers. Somewhat lower aggregate diameters observed in the acetylated MFC were assumed to be due to decreased MFC hydrophilicity and improved chemical affinity with the PLA matrix. The MFC networks in the commingled compounds were severely disrupted after twin-screw extrusion. This confirmed the limited deformability of the networks inferred from the extensive syneresis during the initial compression molding step, and accounted for substantial losses in stiffness reinforcement by the MFC after extrusion. 相似文献
38.
Harinash Rao Sulin Choo Sri Raja Rajeswari Mahalingam Diajeng Sekar Adisuri Priya Madhavan Abdah Md. Akim Pei Pei Chong 《Molecules (Basel, Switzerland)》2021,26(7)
Biofilms play an essential role in chronic and healthcare-associated infections and are more resistant to antimicrobials compared to their planktonic counterparts due to their (1) physiological state, (2) cell density, (3) quorum sensing abilities, (4) presence of extracellular matrix, (5) upregulation of drug efflux pumps, (6) point mutation and overexpression of resistance genes, and (7) presence of persister cells. The genes involved and their implications in antimicrobial resistance are well defined for bacterial biofilms but are understudied in fungal biofilms. Potential therapeutics for biofilm mitigation that have been reported include (1) antimicrobial photodynamic therapy, (2) antimicrobial lock therapy, (3) antimicrobial peptides, (4) electrical methods, and (5) antimicrobial coatings. These approaches exhibit promising characteristics for addressing the impending crisis of antimicrobial resistance (AMR). Recently, advances in the micro- and nanotechnology field have propelled the development of novel biomaterials and approaches to combat biofilms either independently, in combination or as antimicrobial delivery systems. In this review, we will summarize the general principles of clinically important microbial biofilm formation with a focus on fungal biofilms. We will delve into the details of some novel micro- and nanotechnology approaches that have been developed to combat biofilms and the possibility of utilizing them in a clinical setting. 相似文献
39.
Sul Lee Sunho Jeong Dongjo Kim Bong Kyun Park Jooho Moon 《Superlattices and Microstructures》2007,42(1-6):361
We have fabricated a solution-processed ZnO thin-film transistor without vacuum deposition. ZnO nanoparticles were prepared by the polyol method from zinc acetate, polyvinyl pyrrolidone, and diethyleneglycol. The solution-processable semiconductor ink was prepared by dispersing the synthesized ZnO in a solvent. Inverted stagger type thin-film transistors were fabricated by spin casting the ZnO ink on the heavily doped Si wafer with 200 nm thick SiO2, followed by evaporation of Cr/Au source and drain electrodes. After the drying and heat treatment at 600 C, a relatively dense ZnO film was obtained. The film characteristics were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). In order to obtain the electrical properties of the solution-derived transistor, the on–off ratio, threshold voltage, and mobility were measured. 相似文献
40.
An Aluminophosphate Molecular Sieve with 36 Crystallographically Distinct Tetrahedral Sites
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Jun Kyu Lee Alessandro Turrina Liangkui Zhu Seungwan Seo Dr. Daliang Zhang Dr. Paul A. Cox Prof. Paul A. Wright Prof. Shilun Qiu Prof. Suk Bong Hong 《Angewandte Chemie (International ed. in English)》2014,53(29):7480-7483
The structure of the new medium‐pore aluminophosphate molecular sieve PST‐6 is determined by the combined use of rotation electron diffraction tomography, synchrotron X‐ray powder diffraction, and computer modeling. PST‐6 was prepared by calcination of another new aluminophosphate material with an unknown structure synthesized using diethylamine as a structure‐directing agent, which is thought to contain bridging hydroxy groups. PST‐6 has 36 crystallographically distinct tetrahedral sites in the asymmetric unit and is thus crystallographically the most complex zeolitic structure ever solved. 相似文献