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991.
Chih-Hung?LoEmail author Tsing-Tshih?Tsung Liang-Chia?Chen Chun-His?Su Hong-Ming?Lin 《Journal of nanoparticle research》2005,7(2-3):313-320
The optimal parameters are found for preparing nanofluid in our submerged arc nanoparticle synthesis system (SANSS) using a copper electrode. A suspended copper oxide nanofluid is thus produced at the current of 8.5–10 A, voltage of 220 V, pulse duration of 12 μs, and dielectric liquid temperature of 2°C. The CuO nanoparticle are characterized by transmission electron microscopy (TEM), field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), electron diffraction pattern (SAD) and electron spectroscopy for chemical analysis (ESCA). The equality volume spherical diameter of the obtained copper oxide particle is 49.1 nm, regular shape and narrow size distribution.This revised version was published online in August 2005 with a corrected issue number. 相似文献
992.
993.
In this paper we study the nature of the singularity of the Kontsevichs solution of the WDVV equations of associativity. We prove that it corresponds to a singularity in the change of two coordinates systems of the Frobenius manifold given by the quantum cohomology of CP2.
Mathematics Subject Classifications (2000) 53C99, 32D99, 14N35, 88A99. 相似文献
994.
Summary Polymer-supported and polymeric chiral guanidines carrying an imidazolidine skeleton are designed as polymer-based base catalysts.
Thus, (R)-2-[(S)-1-hydroxymethyl-2-phenylethylimino]-4-phenylimidazolidine was newly prepared from (R)-phenylglycine as the key functional unit of these guanidines. Application of the polymer-based chiral guanidines to the
asymmetric Michael reaction of t-butyl diphenyliminoacetate with MVK led to expected asymmetric induction in the Michael adduct with moderate enantioselectivity
in the use of the latter polymeric chiral guanidines. 相似文献
995.
Advances in organic synthesis using polymer-supported reagents and scavengers under microwave irradiation 总被引:1,自引:0,他引:1
Bhattacharyya S 《Molecular diversity》2005,9(4):253-257
Summary Microwave-assisted and polymer-supported organic syntheses have emerged independently as versatile tools for rapid generation
of organic molecules. Chemists are increasingly looking for a combination of both techniques for efficient organic synthesis.
This review covers the recent literature on organic synthesis using microwave heating in conjunction with polymer-supported
reagents and scavengers. 相似文献
996.
Toshinobu?YogoEmail author Reimon?Fukuzawa Wataru?Sakamoto Shin-ichi?Hirano 《Journal of nanoparticle research》2005,7(6):633-640
Nanocrystalline BaTiO3 particles modified with polarizable ligands were synthesized through hydrolysis of modified metal–organics below 100°C. BaTiO3 precursor was synthesized from barium metal, titanium isopropoxide and polarizable ligands in a mixture of ethanol and 2-ethoxyethanol.
The modified Ba–Ti complex alkoxide was hydrolyzed yielding BaTiO3 particles modified with organics. The crystallinty of nanometer-sized particles was dependent upon the hydrolysis conditions,
and increased with increasing water amount and time. The nanocrystalline particles were identified to be BaTiO3 by X-ray diffraction (XRD) and electron diffraction. A fluid consisting of modified BaTiO3 particles and silicone oil revealed a typical electrorheological (ER) behavior on applying DC field. The ER behavior was
found to depend upon the kind of ligand. 4-Fluorobenzyloxy modifier revealed the highest yield stress in the ER measurement
among 4-substitued benzyloxy ligands examined. 相似文献
997.
B.?Mosconi P.?RicciEmail author E.?Truhl?k 《The European Physical Journal A - Hadrons and Nuclei》2005,25(2):283-291
The structure of the weak axial pion exchange current is discussed in various models. It is shown how the interplay of the chiral invariance and the double-counting problem restricts uniquely the form of the pion potential term, to the case when the nuclear dynamics is described by the Schrödinger equation with static nucleon-nucleon potential. 相似文献
998.
I.?Giller A.?Ocherashvili T.?Ebertsh?user M.?A.?Moinester S.?SchererEmail author 《The European Physical Journal A - Hadrons and Nuclei》2005,25(2):229-240
We discuss the reaction π-e- → π-e-π0 with the purpose of obtaining information on the γπ → ππ anomalous amplitude
3π. We compare a full calculation at
(p6) in chiral perturbation theory and various phenomenological predictions with the existing data of Amendolia et al. By integrating our theory results using Monte Carlo techniques, we obtain σ = 2.05 nb at
(p6) and σ = 2.17 nb after including the dominant electromagnetic correction. Both results are in good agreement with the experimental cross-section of σ = (2.11±0.47) nb. On the basis of the ChPT results one would extract from the experimental cross-section as amplitudes
3π(0)extr = (9.9±1.1) GeV-3 and
3π(0)extr = (9.6±1.1) GeV-3, respectively, which have to be compared with the low-energy theorem
3π = e/(4π2Fπ3) = 9.72GeV-3. We emphasize the need for new data to allow for a comparison of experimental and theoretical distributions and to obtain
3π with smaller uncertainty. 相似文献
999.
G. F.J.?A?a?osEmail author F.?Baldovin C.?Tsallis 《The European Physical Journal B - Condensed Matter and Complex Systems》2005,46(3):409-417
We perform a throughout numerical study of the average
sensitivity to initial conditions and entropy production for
two symplectically coupled standard maps focusing on the
control-parameter region close to regularity.
Although the system is ultimately strongly chaotic (positive
Lyapunov exponents), it first stays lengthily in
weak-chaotic regions (zero Lyapunov exponents).
We argue that the nonextensive
generalization of the classical formalism is an adequate
tool in order to get nontrivial information about the first stage of this crossover
phenomenon.
Within this context we analyze the relation
between the power-law sensitivity to initial conditions and the
entropy production. 相似文献
1000.
Wangyu?HuEmail author Shifang?Xiao Jianyu?Yang Zhi?Zhang 《The European Physical Journal B - Condensed Matter and Complex Systems》2005,45(4):547-554
Molecular dynamics calculations have been performed to study the melting
evolution, atomic diffusion and vibrational behavior of bcc metal vanadium
nanoparticles with the number of atoms ranging from 537 to 28475 (diameters
around 2–9 nm). The interactions between atoms are described using an
analytic embedded-atom method. The obtained results reveal that the melting
temperatures of nanoparticles are inversely proportional to the reciprocal
of the nanoparticle size, and are in good agreement with the predictions of
the thermodynamic liquid-drop model. The melting process can be described as
occurring in two stages, firstly the stepwise premelting of the surface
layer with a thickness of 2–3 times the perfect lattice constant, and then
the abrupt overall melting of the whole cluster. The heats of fusion of
nanoparticles are also inversely proportional to the reciprocal of the
nanoparticle size. The diffusion is mainly localized to the surface layer at
low temperatures and increases with the reduction of nanoparticle size, with
the temperature being held constant. The radial mean square vibration
amplitude (RMSVA) is developed to study the anharmonic effect on surface
shells. 相似文献