全文获取类型
收费全文 | 2783篇 |
免费 | 174篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 38篇 |
综合类 | 2篇 |
化学工业 | 757篇 |
金属工艺 | 46篇 |
机械仪表 | 70篇 |
建筑科学 | 111篇 |
矿业工程 | 1篇 |
能源动力 | 100篇 |
轻工业 | 276篇 |
水利工程 | 24篇 |
石油天然气 | 3篇 |
无线电 | 244篇 |
一般工业技术 | 437篇 |
冶金工业 | 154篇 |
原子能技术 | 19篇 |
自动化技术 | 679篇 |
出版年
2024年 | 6篇 |
2023年 | 52篇 |
2022年 | 149篇 |
2021年 | 182篇 |
2020年 | 85篇 |
2019年 | 80篇 |
2018年 | 119篇 |
2017年 | 73篇 |
2016年 | 141篇 |
2015年 | 93篇 |
2014年 | 135篇 |
2013年 | 210篇 |
2012年 | 182篇 |
2011年 | 237篇 |
2010年 | 149篇 |
2009年 | 151篇 |
2008年 | 155篇 |
2007年 | 128篇 |
2006年 | 109篇 |
2005年 | 84篇 |
2004年 | 63篇 |
2003年 | 55篇 |
2002年 | 42篇 |
2001年 | 23篇 |
2000年 | 26篇 |
1999年 | 29篇 |
1998年 | 41篇 |
1997年 | 35篇 |
1996年 | 32篇 |
1995年 | 15篇 |
1994年 | 19篇 |
1993年 | 9篇 |
1992年 | 9篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 6篇 |
1988年 | 3篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1982年 | 5篇 |
1981年 | 3篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1977年 | 1篇 |
1976年 | 3篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1969年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有2961条查询结果,搜索用时 15 毫秒
151.
Giulia Giuntoli Luca Rosi Marco Frediani Barbara Sacchi Piero Frediani 《应用聚合物科学杂志》2012,125(4):3125-3133
A series of sixteen fluoro-functionalized poly(lactic acid)s were synthesised using two commercial fluorinated alcohols [3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-1-octanol and 4-(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)benzyl alcohol] as co-initiators in the ring-opening polymerization of L-lactide and rac-lactide (the racemic mixture of L- and D-lactide) catalyzed by Tin(II) 2-ethylhexanoate. The polymers were characterized by NMR, IR, GPC, DSC and tested as potential protective coating for stone. The performances were comparatively evaluated in terms of water protection efficacy and colour changes of the treated stone. Furthermore, the photo-stability of nine selected polymers under Solar Box condition was also investigated. It has been shown that the presence of fluorine makes the stone more water-repellent. The polymers showed also interesting photo-stability and some of them provided a behavior close to PLA-FLK-PLA block copolymers recently reported in the literature, in spite of their lower fluorine content © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
152.
Palle Breistein Jonas Johansson Ismail Ibrahem Shuangzheng Lin Luca Deiana Junliang Sun Armando Cordova 《Advanced Synthesis \u0026amp; Catalysis》2012,354(6):1156-1162
The highly enantioselective cascade reaction between N‐protected α‐cyanoglycine esters and α,β‐unsaturated aldehydes is disclosed. The reaction represents a one‐step entry to polysubstituted 5‐hydroxyproline derivatives having a quaternary α‐stereocenter generally in high yields with up to >95:5 dr and 99:1 er. It is also a direct catalytic two‐step entry to functionalized α‐quaternary proline derivatives. 相似文献
153.
PEGylated chitosan derivatives: Synthesis, characterizations and pharmaceutical applications 总被引:1,自引:0,他引:1
Luca CasettariDriton Vllasaliu Enzo CastagninoSnjezana Stolnik Steven Howdle Lisbeth Illum 《Progress in Polymer Science》2012,37(5):659-685
This review sets out to describe and discuss the synthetic approaches and the fields of application of PEGylated chitosan copolymers especially for medical use. The PEGylation of chitosan and chitosan derivatives is able to add new physicochemical properties to the cationic polysaccharide polymers, thereby overcoming some limitations, especially regarding their solubility and their use in drug and gene delivery (DNA and siRNA). All methods of derivatization have been considered and described together with the different methods of characterization of the copolymers. The capacities of PEGylated chitosan to reduce chitosan toxicity, to enhance membrane permeation and to form thermosensitive hydrogels have also been discussed. 相似文献
154.
155.
Andrea Luca Tasca Eleonora Stefanelli Anna Maria Raspolli Galletti Riccardo Gori Gemma Mannarino Sandra Vitolo Monica Puccini 《化学工程与技术》2020,43(12):2382-2392
Hydrothermal carbonization of sewage sludge was carried out with the aim to evaluate the influence of process severity and initial solid content. Response surface methodology was applied to model yield and C yield responses. Enhanced dewaterability performance was recorded under mild processing conditions. The treatment promoted concentration and immobilization of Pb, Cd, Ni, Zn, and Cu. Variation of the solid content showed a stronger influence than severity on average yield and C yield. Higher heating values (HHVs) and energy retention efficiencies (EREs) of hydrochars obtained at the lowest solid content displayed the lowest values. Hence, the energy requirements of a first dewatering step should be compared with the related improvement in terms of HHV and ERE when sludge is used as feedstock. 相似文献
156.
Dr. Mariafrancesca Hyeraci Dr. Marialuigia Colalillo Prof. Luca Labella Prof. Fabio Marchetti Prof. Simona Samaritani Dr. Valeria Scalcon Prof. Maria Pia Rigobello Prof. Lisa Dalla Via 《ChemMedChem》2020,15(15):1464-1472
Platinum(II) complexes of the type [Pt(Cl)(PPh3){(κ2-N,O)-(1{C(R)=N(OH)-2(O)C6H4})}] with R=Me, H, ( 1 and 2 ) were synthesized and characterized. Single-crystal X-ray diffraction confirmed the proposed (SP4-3) configuration for 1 . Study of the antiproliferative activity, performed on a panel of human tumor cell lines and on mesothelial cells, highlighted complex 2 as the more effective. In particular, it showed a remarkable cytotoxicity in ovarian carcinoma cells (A2780) and interestingly, a significant antiproliferative effect on cisplatin resistant cells (A2780cis). Investigation into the intracellular mechanism of action demonstrated that 2 had a lower ability to platinate DNA than did cisplatin, which was taken as reference, and a notably higher uptake in resistant cells. A significant accumulation in mitochondria, along with the ability to induce concentration-dependent mitochondrial membrane depolarization and intracellular reactive oxygen species production, allowed us to propose a mitochondrion-mediated pathway as responsible for the interesting cytotoxic profile of complex 2 . 相似文献
157.
Insa Thale Sarah Maskri Lucie Grey Luca Matteo Todesca Prof. Dr. Thomas Budde Dr. Ivan Maisuls Prof. Dr. Cristian A. Strassert Prof. Dr. Oliver Koch Prof. Dr. Albrecht Schwab Prof. Dr. Bernhard Wünsch 《ChemMedChem》2023,18(2):e202200551
The Ca2+ activated K+ channel KCa3.1 is overexpressed in several human tumor cell lines, e. g. clear cell renal carcinoma, prostate cancer, non-small cell lung cancer. Highly aggressive cancer cells use this ion channel for key processes of the metastatic cascade such as migration, extravasation and invasion. Therefore, small molecules, which are able to image this KCa3.1 channel in vitro and in vivo represent valuable diagnostic and prognostic tool compounds. The [18F]fluoroethyltriazolyl substituted senicapoc was used as positron emission tomography (PET) tracer and showed promising properties for imaging of KCa3.1 channels in lung adenocarcinoma cells in mice. The novel senicapoc BODIPY conjugates with two F-atoms ( 9 a ) and with a F-atom and a methoxy moiety ( 9 b ) at the B-atom led to the characteristic punctate staining pattern resulting from labeling of single KCa3.1 channels in A549-3R cells. This punctate pattern was completely removed by preincubation with an excess of senicapoc confirming the high specificity of KCa3.1 labeling. Due to the methoxy moiety at the B-atom and the additional oxyethylene unit in the spacer, 9 b exhibits higher polarity, which improves solubility and handling without reduction of fluorescence quantum yield. Docking studies using a cryo-electron microscopy (EM) structure of the KCa3.1 channel confirmed the interaction of 9 a and 9 b with a binding pocket in the channel pore. 相似文献
158.
Dr. Morteza Abdoli Dr. Viviana De Luca Prof. Clemente Capasso Prof. Claudiu T. Supuran Prof. Raivis Žalubovskis 《ChemMedChem》2023,18(6):e202200658
Two novel sulfaguanidine series, six N-(N,N′-dialkyl/dibenzyl-carbamimidoyl) benzenesulfonamide derivatives and nine N-(N-alkyl/benzyl-carbamimidoyl) benzenesulfonamide derivatives, were obtained by desulfidative amination of easily accessible dimethyl arylsulfonylcarbonimidodithioates under catalyst- and base-free conditions. The newly synthesized compounds were tested for the inhibition of four different isozymes of human carbonic anhydrase (hCA I, II, IX and XII, EC 4.2.1.1). Both series reported here were inactive against the off-target isozymes hCA I and II (Ki>100 μM). Interestingly, all investigated compounds inhibited both target isozymes hCA IX and XII in the submicromolar to micromolar ranges in which Ki values spanned from 0.168 to 0.921 μM against hCA IX and from 0.335 to 1.451 μM against hCA XII. The results indicated that N-(N-alkyl/benzyl-carbamimidoyl) benzenesulfonamides were slightly more potent inhibitors than N-(N,N′-dialkyl/dibenzyl-carbamimidoyl) benzenesulfonamides. Among the evaluated compounds, N-n-octyl-substituted N-carbamimidoylbenzenesulfonamide showed the most significant activity with a Ki value of 0.168 μM against hCA IX, which was four-fold more selective toward this isozyme versus hCA XII. Again, another derivative from N-(N-alkyl/benzyl-carbamimidoyl) benzenesulfonamide series, N-p-methylbenzyl-substituted N-carbamimidoylbenzenesulfonamide, demonstrated superior inhibitory activity against hCA XII with a Ki value of 0.335 μM. 相似文献
159.
The aim of this work was to determine a cost-optimal design of the distillation unit of the Andrussow process. For this purpose, a feed with a mass flow rate of 121 t h−1 and a concentration of ca. 2 wt % hydrogen cyanide (HCN) was considered. An approach for a cost-optimal process intensification was developed with the goal to achieve the desired product qualities, while minimizing the organonitrile accumulation in the column. For this purpose, the simple distillation column of the established cost-optimal design of the base case was extended to a configuration with a side stripper with taking into consideration heat integration in the process. It was found that this new configuration allows a much smaller accumulation of organonitriles in the main column; reducing thereby the operation issues of the process while decreasing considerably the total annual cost of the distillation unit by 61 % as compared to that of the base case design. 相似文献
160.
Arturo Di Fraia Edoardo Miliotti Andrea Maria Rizzo Giulia Zoppi Giuseppe Pipitone Raffaele Pirone Luca Rosi David Chiaramonti Samir Bensaid 《American Institute of Chemical Engineers》2023,69(1):e17652
Lignin-rich stream from lignocellulosic ethanol production was converted into biocrude by continuous hydrothermal liquefaction (HTL) while hydrogen was produced by aqueous phase reforming (APR) of the HTL aqueous by-product. The effects of Na2CO3 and NaOH were investigated both in terms of processability of the feedstock as well as yield and composition of the obtained products. A maximum biocrude yield of 27 wt% was reached in the NaOH-catalyzed runs. A relevant amount of dissolved phenolics were detected in the co-produced aqueous phase (AP), and removed by liquid–liquid extraction using butyl acetate or diethyl ether, preserving the APR catalyst stability and reaching an hydrogen yield up to 146 mmol H2 L−1 AP. Preliminary mass balances integrating HTL and APR showed that the hydrogen provided by APR may account for up to 46% of the hydrogen amount theoretically required for upgrading the HTL biocrude, thus significantly improving the process performance and sustainability. 相似文献