全文获取类型
收费全文 | 402篇 |
免费 | 7篇 |
国内免费 | 3篇 |
专业分类
化学 | 301篇 |
晶体学 | 6篇 |
力学 | 27篇 |
数学 | 20篇 |
物理学 | 58篇 |
出版年
2023年 | 9篇 |
2022年 | 47篇 |
2021年 | 28篇 |
2020年 | 14篇 |
2019年 | 17篇 |
2018年 | 12篇 |
2017年 | 9篇 |
2016年 | 12篇 |
2015年 | 13篇 |
2014年 | 15篇 |
2013年 | 28篇 |
2012年 | 25篇 |
2011年 | 22篇 |
2010年 | 5篇 |
2009年 | 9篇 |
2008年 | 11篇 |
2007年 | 16篇 |
2006年 | 10篇 |
2005年 | 10篇 |
2004年 | 12篇 |
2003年 | 7篇 |
2002年 | 5篇 |
2001年 | 3篇 |
2000年 | 9篇 |
1999年 | 4篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1971年 | 1篇 |
1969年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有412条查询结果,搜索用时 15 毫秒
181.
Taha Chabbah Houyem Abderrazak Patrice Saint Martin Herv Casabianca Hans R. Kricheldorf Saber Chatti 《先进技术聚合物》2020,31(10):2339-2350
In this study, biomass‐derived Glux was used as a monomer in the polymerization of a novel semi‐aromatic polyethersulfone and polyester. The characterization of the synthesized polymers was carried out by means of MALDI‐TOF and NMR spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. These two polymers were tested as sorbent phases of two families of pollutants (benzene derivatives and pesticides) in water. The analysis of the target hydrophilic pollutants was successfully achieved using high performance liquid chromatography meanwhile gas chromatography was applied for the detection of the hydrophobic pollutants. The adsorption data demonstrate that the novel polyethersulfone based on Glux can effectively remove the studied organic pollutants (polar and non polar, 90% to 100%) at environmental concentration (tested concentration: 1 mg L?1) simultaneously when present in mixtures. 相似文献
182.
Hichem Mallek Corinne Jegat Nathalie Mignard Mohamed Taha Majdi Abid Souhir Abid 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(7):728-737
Thermally reversible cross-linked polycaprolactone-urethane (PCL-U) was prepared in one-step procedure. The PCL-U networks were synthesized from a di-isocyanate (4,4′-methylene bis(cyclohexylisocyanate) (HMDI) and hydroxyl bearing macromers and monomers: hydroxy-terminated PCL, glycerol and a di-alcohol Diels-Alder (DA) adduct. This adduct was used to introduce both diene and dienophile functions in the structure and also to protect the maleimide functions from polymerization. The thermoresponsive behavior of the material was characterized by commonly used methods such as solubility tests at different temperatures and differential scanning calorimetry analyses to highlight rDA reactions and also by rheological analysis. The effects of the cooling rate, the molar mass of polycaprolactone as well as the molar ratio [di-Isocyanate]/[PCL-diol] on the cross-linking/de-cross-linking temperatures were also analyzed. The reversible networks obtained have a self-healing behavior. 相似文献
183.
184.
Recent findings in neuroscience have led to the development of several new models describing the processes in the neocortex. These models excel at cognitive applications such as image analysis and movement control. This paper presents a hardware architecture to speed up image content recognition through a recently proposed model of the visual cortex. The system is based on a set of parallel computation nodes implemented in an FPGA. The design was optimized for hardware by reducing the data storage requirements, and removing the need for multiplies and divides. The reconfigurable logic hardware implementation running at 121 MHz provided a speedup of 148 times over a 2 GHz AMD Opteron processor. The results indicate the feasibility of specialized hardware to accelerate larger biological scale implementations of the model. 相似文献
185.
Aurora-A kinase plays a central role in mitosis, where aberrant activation contributes to cancer by promoting cell cycle progression, genomic instability, epithelial-mesenchymal transition, and cancer stemness. Aurora-A kinase inhibitors have shown encouraging results in clinical trials but have not gained Food and Drug Administration (FDA) approval. An innovative computational workflow named Docking-based Comparative Intermolecular Contacts Analysis (dbCICA) was applied—aiming to identify novel Aurora-A kinase inhibitors—using seventy-nine reported Aurora-A kinase inhibitors to specify the best possible docking settings needed to fit into the active-site binding pocket of Aurora-A kinase crystal structure, in a process that only potent ligands contact critical binding-site spots, distinct from those occupied by less-active ligands. Optimal dbCICA models were transformed into two corresponding pharmacophores. The optimal one, in capturing active hits and discarding inactive ones, validated by receiver operating characteristic analysis, was used as a virtual in-silico search query for screening new molecules from the National Cancer Institute database. A fluorescence resonance energy transfer (FRET)-based assay was used to assess the activity of captured molecules and five promising Aurora-A kinase inhibitors were identified. The activity was next validated using a cell culture anti-proliferative assay (MTT) and revealed a most potent lead 85(NCI 14040) molecule after 72 h of incubation, scoring IC50 values of 3.5–11.0 μM against PANC1 (pancreas), PC-3 (prostate), T-47D and MDA-MB-231 (breast)cancer cells, and showing favorable safety profiles (27.5 μM IC50 on fibroblasts). Our results provide new clues for further development of Aurora-A kinase inhibitors as anticancer molecules. 相似文献
186.
Nonlinear Dynamics - Based on the post-inhibitory rebound (PIR) spike induced by inhibitory current pulse, in the present paper, a novel counterintuitive phenomenon that the inhibitory autapse with... 相似文献
187.
Hassan Taha 《Applicable analysis》2013,92(10):961-970
We consider the approximation family {f? } introduced by Guillaume and Seeger in the case of affine functions. We generalise the framework to the case of convex functions and give some further properties. 相似文献
188.
Yuan‐Bin Cheng Kuang‐Liang Lo Ching‐Yeu Chen Ashraf Taha Khalil Ya‐Ching Shen 《Helvetica chimica acta》2008,91(12):2308-2315
Investigation of the MeOH/CH2Cl2 extract of the soft coral Cespitularia hypotentaculata collected in Taiwan has resulted in the isolation of four new verticillane‐type diterpenoids, cespihypotins M–P ( 1 – 4 ). Compounds 2 and 3 are C(20)‐epimers. Compound 4 with a C?O group at C(10) and a methoxycarbonyl group at C(12) may be an important precursor of cespitularins and cespihypotins. The structures of these compounds were determined on the basis of spectroscopic analyses. 相似文献
189.
Ismail Taha Ibrahim 《Journal of Radioanalytical and Nuclear Chemistry》2009,281(3):669-674
Metronidazole (MTNZ) is an antiprotozoa drug, could be labeled with the 99mTc. MTZL could be used as an ideal vehicle to deliver radioactive decay energy of 99mTc to the sites of tumor, thus facilitate tumor imaging. The process of labeling was done using tin chloride as reducing agent.
The optimum conditions required to label 25 μg MTZL were 100 μg stannous chloride, 30 min reaction time, room temperature
at pH 7–9 using 0.5 M phosphate buffer. The radiochemical purity of the labeled compound, at the above conditions, was determined
using paper chromatography. The yield was about 93%. About 2.5 × l06 of Ehrlich Ascites Carcinoma (EAC) was injected intrapritoneally (i.p) to produce ascites and intramuscularly (i.m) in the
right thigh to produce solid tumor in female mice. Biodistribution studies were carried out by injecting solution of 99mTc-MTZL in normal and tumor bearing mice. The uptake in ascites was over 5% of the injected dose per gram tissue body weight,
at 4 h post injection and above 4% in solid tumor. These data revealed localization of the tracer in the tumor tissues with
high percentage sufficient to use 99 mTc MTZL as promising tool for diagnosis of tumor. 相似文献
190.
Peapod‐Type Nanocomposites through the In Situ Growth of Gold Nanoparticles within Preformed Hexaniobate Nanoscrolls
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)
Dr. Shiva Adireddy Cecilia E. Carbo Taha Rostamzadeh Dr. Jose M. Vargas Prof. Leonard Spinu Prof. John B. Wiley 《Angewandte Chemie (International ed. in English)》2014,53(18):4614-4617
A facile in situ method to grow Au nanoparticles (NPs) in hexaniobate nanoscrolls is applied to the formation of plasmonic Au@hexaniobate and bifunctional plasmonic‐magnetic Au‐Fe3O4@hexaniobate nanopeapods (NPPs). Utilizing a solvothermal treatment, rigid multiwalled hexaniobate nanoscrolls and partially filled Fe3O4@hexaniobate NPPs were first fabricated. These nanostructures were then used as templates for the controlled in situ growth of Au NPs. The resulting peapod structures exhibited high filling fractions and long‐range uniformity. Optical measurements showed a progressive red shift in plasmonic behavior between Au NPs, Au NPPs, and Au‐Fe3O4 NPPs; magnetic studies found that the addition of gold in the Fe3O4@hexaniobate NPPs reduced interparticle coupling effects. The development of this approach allows for the routine bulk preparation of noble‐metal‐containing bifunctional nanopeapod materials. 相似文献