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41.
Dandan Shi Xiaobo Yu Liangliang Chen Daoliang Chen Zitong Liu Xisha Zhang Guanxin Zhang Deqing Zhang 《中国化学》2020,38(10):1075-1080
The development of selenophene‐flanked DPP (SeDPP) based copolymers, especially for the ambipolar ones, lags behind other aromatic group flanked DPP‐based polymers. Herein, we report two new ambipolar SeDPP‐based conjugated polymers. One is the alternating polymer PSeDPPFT with normal SeDPP and 3,4‐difluorothiophene units. The other is PSeFDFT , in which the electron acceptor unit is replaced by a new SeDPP derivative, referred as to half‐fused SeDPP. The more planar structure of half‐fused SeDPP endows the backbone of PSeFDFT with good rigidity and planarity. Both polymers exhibit ambipolar transporting properties in air. The PSeFDFT based field‐effect transistors (FETs) display higher and more balanced ambipolar properties with μhave of 0.27 cm2·V–1·s–1, μeave of 0.18 cm2·V–1·s–1, and μhave/μeave of 1.5 than those of PSeDPPFT (μhave = 0.11 cm2·V–1·s–1, μeave = 0.042 cm2·V–1·s–1, and μh/μe = 2.6). This is attributed to the more planar structure, lower LUMO level, higher HOMO level, and better interchain packing orientations of PSeFDFT by comparing with PSeDPPFT . Therefore, a new molecular design strategy to modulate the hole and electron transporting properties is proposed for conjugated D‐A polymers. 相似文献
42.
There are several developments taking place in the field of sensors driven by the world today requirements. One of the most important novelties of the last two decades in the field is represented by the hydrogel-based sensors which constitute a wide family of innovative smart sensing devices relevant for many different applications. Hydrogels in fact are hydrophilic, biocompatible and highly water swellable polymer networks able to convert chemical energy into mechanical energy, with the great peculiarity to be able to respond to external stimuli. These characteristics have ensured them considerable recognition as valuable tool for smart sensing and diagnostics. The aim of this review is to focus on the advances obtained in the field in the last ten years. 相似文献
43.
Luis Palomo Rafael Rodríguez Samara Medina Emilio Quio Juan Casado Flix Freire Francisco J. Ramírez 《Angewandte Chemie (International ed. in English)》2020,59(23):9080-9087
Poly(phenylacetylene)s are a family of helical polymers constituted by conjugated double bonds. Raman spectra of these polymers show a structural fingerprint of the polyene backbone which, in combination with its helical orientation, makes them good candidates to be studied by Raman optical activity (ROA). Four different well‐known poly(phenylacetylene)s adopting different scaffolds and ten different helical senses have been prepared. Raman and ROA spectra were recorded and allowed to establish ROA‐spectrum/helical‐sense relationships: a left/right‐handed orientation of the polyene backbone (Mhelix/Phelix) produces a triplet of positive/negative ROA bands. Raman and ROA spectra of each polymer exhibited the same profile, and the sign of the ROA spectrum was opposite to the lowest‐energy electronic circular dichroism (ECD) band, indicating a resonance effect. Resonance ROA appears then as an indicator of the helical sense of poly(phenylacetylene)s, especially for those with an extra Cotton band in the ECD spectrum, where a wrong helical sense is assigned based on ECD, while ROA alerts of this misassignment. 相似文献
44.
《Analytical letters》2012,45(13):2417-2429
Abstract Antibodies to a p-cresol bovine serum albumin conjugate have been produced and incorporated into a conducting polymer to form an electro-immunological sensing system. Using flow injection analysis and pulsed electrochemical detection sensitive, reproducible and rapid responses to p-cresol and other phenolics can be obtained. The sensor is reusable. 相似文献
45.
Three one‐dimensional coordination polymers, [MnCl2(4‐pyterpy)]∙2CHCl3 ( 1 ), [Mn(NO3)2(4‐pyterpy)]∙CHCl3 ( 2 ) and [Ag(NO3)(3‐pyterpy)]∙H2O ( 3 ) (4‐pyterpy = 4′‐(4‐pyridyl)‐2,2′:6′,2″‐terpyridine and 3‐pyterpy = 4′‐(3‐pyridyl)‐2,2′:6′,2″‐terpyridine) were synthesized and characterized by X‐ray diffraction. All three compounds exhibit a rare “head‐to‐tail” coordination of the multidentate ligand, but differ significantly in their polymer chain conformations. Additionally, the fluorescent properties of all three compounds were investigated and show a weak, ligand‐centered fluorescence at 416–418 nm. 相似文献
46.
47.
Impedance characterization at different temperatures has been used to investigate the conductive behavior of Poly(3-hexylthiophene) (P3HT), prepared in different solvents, as the semiconductor layer in organic multilayer capacitor. It has been found that the P3HT films using chloroform and toluene solvents exhibit an enhancement in conductivity by heating following an Arrhenius law with an activation energy transition from 0.004 to 0.026 eV and from 0.002 to 0.015 eV at ~313 K, respectively, which originates from band tail hopping that occurs around the Fermi edge. The boiling point of the used solvents can affect P3HT crystallization process, which causes the difference in conduction and activation energy. 相似文献
48.
Bin Yu 《Journal of Physics and Chemistry of Solids》2010,71(4):468-116
Casein, a natural biopolymer contained in milk, has been successfully intercalated into a Ca-Al-LDH host structure. Synthesis was performed by rehydration of tricalcium aluminate in the presence of casein. The resulting nanohybrids were characterized by powder X-ray diffraction (XRD), elemental analysis, infrared spectroscopy (IR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Further experiments revealed that the single protein strains intercalate instead of the entire casein sub micelles, which are present in milk. Additionally, the pure phospho protein fractions α- and β-casein, which make up ∼80 wt% of total casein were isolated and intercalated into the Ca-Al-LDH host structure, yielding a biopolymer-inorganic hybrid material. 相似文献
49.
P. M. Diesinger D. W. Heermann 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,62(2):209-214
We study the influence of excluded volume interactions
on the behaviour of the mean average crossing number (mACN) for
random off-lattice walks. We investigated Gaussian and equilateral
off-lattice random walks with and without ellipsoidal excluded
volume up to chain lengths of N = 1500 and equilateral random
walks on a cubic lattice up to N = 20000. We find that the
excluded volume interactions have a strong influence on the
behaviour of the local crossing number 〈 a(l1,l2)
〉 at very short distances but only a weak one at large
distances. This behaviour is the basis of the proof
in [ Y. Diao et al., Math. Gen. 36, 11561 (2003); Y. Diao and C. Ernst, Physical and Numerical Models in Knot
Theory Including Applications to the Life Sciences] for the dependence of the mean
average crossing number on the chain length N. We show that the
data is compatible with an Nln(N)-bahaviour for the mACN, even
in the case with excluded volume. 相似文献
50.
K. Broderix M. Weigt A. Zippelius 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(3):441-455
We consider the gelation of particles which are permanently connected by random crosslinks, drawn from an ensemble of finite-dimensional
continuum percolation. To average over the randomness, we apply the replica trick, and interpret the replicated and crosslink-averaged
model as an effective molecular fluid. A Mayer-cluster expansion for moments of the local static density fluctuations is set
up. The simplest non-trivial contribution to this series leads back to mean-field theory. The central quantity of mean-field
theory is the distribution of localization lengths, which we compute for all connectivities. The highly crosslinked gel is
characterized by a one-to-one correspondence of connectivity and localization length. Taking into account higher contributions
in the Mayer-cluster expansion, systematic corrections to mean-field can be included. The sol-gel transition shifts to a higher
number of crosslinks per particle, as more compact structures are favored. The critical behavior of the model remains unchanged
as long as finite truncations of the cluster expansion are considered. To complete the picture, we also discuss various geometrical
properties of the crosslink network, e.g. connectivity correlations, and relate the studied crosslink ensemble to a wider class of ensembles, including the Deam-Edwards
distribution.
Received on 24 April 2002 Published online 14 October 2002
RID="a"
ID="a"deceased
RID="b"
ID="b"e-mail: weigt@theorie.physik.uni-goettingen.de 相似文献