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2.
《Macromolecular bioscience》2018,18(7)
Herein, a new series of non‐ionic dendritic and carbohydrate based amphiphiles is synthesized employing biocompatible starting materials and studied for supramolecular aggregate formation in aqueous solution. The dendritic amphiphiles 12 and 13 possessing poly(glycerol) [G2.0] as hydrophilic unit and C‐10 and C‐18 hydrophobic alkyl chains, respectively, exhibit low critical aggregation concentration (CAC) in the order of 10−5m and hydrodynamic diameters in the 8–10 nm range and supplemented by cryogenic transmission electron microscopy. Ultraviolet‐visible (UV‐Vis) and fluorescence spectroscopy suggests the effective solubilization of hydrophobic guests by the self‐assembled architectures, with the nanotransporters 12 and 13 possessing the highest encapsulation efficiency of 80.74 and 98.03% for curcumin. Efficient uptake of encapsulated curcumin in adenocarcinomic human alveolar basal epithelial (A549) cells is observed by confocal laser scanning microscopy. Amphiphiles 12 and 13 are non‐cytotoxic at the concentrations studied, however, curcumin encapsulated samples efficiently reduce the viability of A549 cells in vitro. Experimental studies indicate the ability of amphiphile 13 to encapsulate 1‐anilinonaphthalene‐8‐sulfonic acid (ANS) and curcumin with binding constant of 1.16 × 1055m −1 and 1.43 × 106m −1, respectively. Overall, our findings demonstrate the potential of these dendritic amphiphiles for the development of prospective nanocarriers for the solubilization of hydrophobic drugs. 相似文献
3.
Among different interaction modalities, force feedback is one of the key technologies to increase the interactivity and immersion of a virtual assembly process. This paper presents a 6-DOF force device with its forward kinematic analysis, workspace simulation, and gravity compensation. To evaluate the device, a prototype system is developed and a case study is conducted to assemble a mechanical product. The users have given positive feedback on the gravity compensation implemented and the general performance of the device. 相似文献
4.
Several phenoxy-imine ligands bearing o-trityl group in phenoxy moiety RN=CHArOH (Ar = C6H2(CPh3)tBu, R = 2,6-Me2C6H3 ( L 1 H ); 2,6-iPr2C6H3 ( L 2 H ); 3,5-(CF3)2C6H3 ( L 3 H ); 3,5-(OMe)2C6H3 ( L 4 H ); CHPh2 ( L 5 H ); CPh3 ( L 6 H )) were synthesized and characterized by1H NMR and 13C NMR spectroscopy. The vanadium complexes based on these ligands LVCl2(THF)2 ( 1–6 ) were synthesized via conventional transmetalation reaction in moderate to high yields. Complexes 1–6 were fully characterized by FT-IR, elemental analyses and the molecular structures of 1 , 2 ·H2O, (2 ·H2O ) 2 (μ-Cl) 2 , 4 , and 5 were confirmed by X-ray crystallographic analysis in which the six-coordinated vanadium centers are in a typical octahedral geometry. Upon activation with Et2AlCl in toluene, complexes 1–6 showed high activities in ethylene polymerization affording polymers with moderate molecular weight (5.9–11.8 × 104 Da). Moreover, in hexane or CH2Cl2, 1–6 /Et2AlCl exhibited enhanced activities. When activated with MAO or MMAO in toluene, these complexes showed relatively low activities but afforded polymers with ultra-high molecular weight (up to 3.30 × 106 Da). 1–6 /Et2AlCl also showed high activities in ethylene/1-hexene copolymerization at room temperature giving moderate molecular-weight polymers (6.5–11.4 × 104 Da) with co-monomer incorporation being of 6.0 ~ 7.8%. 相似文献
5.
Eriko Sato Noboru Tamari Hideo Horibe 《Journal of polymer science. Part A, Polymer chemistry》2019,57(24):2474-2480
Graft copolymers show microphase separated structure as seen in block copolymers and have lower intrinsic viscosity than block copolymers because of a branching structure. Therefore, considering molding processability, especially for polymers containing rigid segments, graft copolymers are useful architectures. In this work, graft copolymers containing rigid poly(diisopropyl fumarate) (PDiPF) branches were synthesized by full free‐radical polymerization process. First, synthesis of PDiPF macromonomers by addition‐fragmentation chain transfer (AFCT) was investigated. 2,2‐Dimethyl‐4‐methylene‐pentanedioic acid dimethyl ester was found to be an efficient AFCT agent for diisopropyl fumarate (DiPF) polymerization because of the suppression of undesired primary radical termination, which significantly took place when common AFCT agent, methyl 2‐(bromomethyl)acrylate, was used. Copolymerization of PDiPF macromonomer with ethyl acrylate accomplished the generation of the graft copolymer having flexible poly(ethyl acrylate) backbone and rigid PDiPF branches. The graft copolymer showed a microphase separated structure, high transparency, and characteristic thermal properties to PDiPF and poly(ethyl acrylate). © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 2474–2480 相似文献
6.
Luis Rodriguez‐Guadarrama 《大分子反应工程》2019,13(5)
One of the most important reasons for modeling polymerization processes is to provide a tool for estimating the risks of runaway reactions in polymer industry. This is especially important for batch processes, such as anionic polymerization of isoprene or butadiene. This work presents a theoretical and experimental research of the anionic polymerization of isoprene using cyclohexane as solvent and n‐butyllithium as initiator. In the first part, a phenomenological kinetic expression is obtained that describes the anionic polymerization of isoprene initiated by n‐butyllithium in cyclohexane. In the second, the mass and energy balance equations are solved to model the anionic polymerization of isoprene in a quasi‐adiabatic batch reactor. Adjustment of reactor parameters is made using the data obtained from a laboratory reactor. The proposed model predicts adequately the obtained temperature, pressure, and conversion profiles from this set of experiments. Finally, a mathematical model is developed to predict the behavior for the anionic polymerization of isoprene in an industrial reactor. 相似文献
7.
Ikhlas Gadwal Prakash P. Wadgaonkar Amol B. Ichake Shivshankar R. Mane 《Journal of polymer science. Part A, Polymer chemistry》2019,57(2):146-156
A new approach was developed for synthesis of certain A3B3‐type of double hydrophilic or amphiphilic miktoarm star polymers using a combination of “grafting onto” and “grafting from” methods. To achieve the synthesis of desired miktoarm star polymers, acetyl protected poly(ethylene glycol) (PEG) thiols (Mn = 550 and 2000 g mol?1) were utilized to generate A3‐type of homoarm star polymers through an in situ protective group removal and a subsequent thiol–epoxy “click” reaction with a tris‐epoxide core viz. 1,1,1‐tris(4‐hydroxyphenyl)ethane triglycidyl ether. The secondary hydroxyl groups generated adjacent to the core upon the thiol–epoxy reaction were esterified with α‐bromoisobutyryl bromide to install atom transfer radical polymerization (ATRP) initiating sites. ATRP of N‐isopropylacrylamide (NIPAM) using the three‐arm star PEG polymer fitted with ATRP initiating sites adjacent to the core afforded A3B3‐type of double hydrophilic (PEG)3[poly(N‐isopropylacrylamide)] (PNIPAM)3 miktoarm star polymers. Furthermore, the generated hydroxyl groups were directly used as initiator for ring‐opening polymerization of ε‐caprolactone to prepare A3B3‐type of amphiphilic (PEG)3[poly(ε‐caprolactone)]3 miktoarm star polymers. The double hydrophilic (PEG)3(PNIPAM)3 miktoarm star polymers showed lower critical solution temperature around 34 °C. The preliminary transmission electron microscopy analysis indicated formation of self‐assembly of (PEG)3(PNIPAM)3 miktoarm star polymer in aqueous solution. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 146–156 相似文献
8.
Fei Zhong Pingquan Wang Yi He Chunlin Chen Hongjie Li Hao Yu Jingyu Chen 《先进技术聚合物》2019,30(7):1644-1655
Graphene oxide (GO) has triggered significant attention as a new type of self‐assembly membrane material. However, the low filtration flux and unstable performance of GO membrane limit its practical application. Hence, in this work, layered double hydroxides (LDHs), as a 2D material with double‐layer channel structure and positive electricity, were self‐assembled with GO at weight ratio of 7:3 by electrostatic interaction. Then, the GO/LDH hybrids combined with polydopamine (PDA) to obtain stable and high‐flux GO‐based membranes through vacuum filtration and the structure and morphology of as‐prepared samples were characterized by FT‐IR, XRD, XPS, and SEM. Furthermore, the separation performance and surface electronegativity of membranes were tested via pure water flux, rejection efficiency, recycle experiments, and zeta potential. Results revealed that the stability and flux of composite membrane were enhanced significantly compared with neat GO‐based membrane. Further, the dye rejection rate of methylene blue (MB) is higher than Congo red (CR) and rhodamine B (Rh B) and reached to 99.8%. 相似文献
9.
Yanguang Bao 《高分子科学杂志,A辑:纯化学与应用化学》2019,56(6):605-608
In this paper, we present a compound, 2,3-diphenyl butyronitrile (DPBN), which can be used as a new and efficient radical initiator for the polymerization of methyl methacrylate (MMA) and styrene (St). Very different from other compounds as a carbon-carbon initiator, DPBN is an unsymmetrically substituted ethane and works with high initiation reactivity at lower temperatures. This new compound as an initiator exhibits various advantages, such as easy preparation, high initiation reactivity, safe use and storage, and convenient handling. 相似文献
10.
Pranesh Chowdhury Abhijit Hazra Maloy Kr. Mondal Bishnupada Roy Debiprasad Roy Shyama Prasad Bayen 《高分子科学杂志,A辑:纯化学与应用化学》2019,56(8):773-780
Poly(acrylic acid) (PAA) and its salt poly(acrylate) (PA) have been synthesized through modified free radical polymerization in environmentally begin aqueous medium under ultrasound to make the process robust. The synthesized polymer is well-characterized through conventional techniques. Its salt is employed to produce highly stable and stimuli sensitive colloidal silver (Ag-PA sol) without using any additional reducing chemical reagents like sodium borohydride, ascorbic acid, hydrazine, etc or UV/Gamma radiation. A detailed mechanistic path of the polymerization and reduction of Ag+ on polyacrylate chains has been evaluated. Finally Ag-PA sol is used for pH sensing through naked eye to eliminate the need for sophisticated instrument for data collection. The present work focuses mainly the development of a low cost pH sensing system based on colorimetric ‘smart polymer’ having high practical utility. The unique structural and photo-physical features of nano-scaled materials open new opportunities for the applications of colorimetric pH sensor. In the present work, Ag nano-clusters capped by PA? are employed as an effective colorimetric pH sensor for the first time, requiring no further functionalization. 相似文献