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101.
The Kauffman model describes a system of randomly connected nodes with dynamics based on Boolean update functions. Though it is a simple model, it exhibits very complex behavior for "critical" parameter values at the boundary between a frozen and a disordered phase, and is therefore used for studies of real network problems. We prove here that the mean number and mean length of attractors in critical random Boolean networks with connectivity one both increase faster than any power law with network size. We derive these results by generating the networks through a growth process and by calculating lower bounds. 相似文献
102.
Erythrocyte membrane permeability coefficients have been determined for a series of amides by a method based on the physical and mathematical modelling of hypotonic haemolysis process. The results show that penetration of the substances occurs by two alternative ways through aqueous pores formed by proteins and by the direct dissolving of the molecules in membrane lipids. This conclusion can be confirmed by the correlation analysis between permeability coefficients of native erythrocytes and those pre-incubated with the monosodium salt of p-chloromercuribenzenesulfonic acid (pCMBS), and the partition coefficients of the substances in hydrophilic-hydrophobic phases. Penetration of substances through hydrophilic channels is limited by the sterical factor and diameter in particular. Permeability coefficients for erythrocytes pre-incubated with pCMBS increase in an accordance with the rise of the partition coefficients with correlation coefficient of 0.94, thereby indicating a lipid route of permeation of molecules through erythrocyte membranes. 相似文献
103.
F.?P.?He?bergerEmail author S.?Hofmann I.?Kojouharov D.?Ackermann 《The European Physical Journal A - Hadrons and Nuclei》2004,22(2):253-260
Isomeric states in 210-215Ra have been populated by the decay of the compound nuclei 216,220Ra produced in irradiations of 204,208Pb with 12C at
MeV. Published values for
-ray energies and half-lives were confirmed for
Ra. Our data for
Ra agree with the
-energies and the half-life measured at the RITU separator, University of Jyväskylä (Finland). Its decay pattern is complex. Two series of
-rays of
keV and
keV were observed. A half-life of
s was measured. The isomeric state is attributed to an 8 + state at E
* = 2053.8keV. A previously unknown isomeric state was assigned to
Ra. It has a half-life of (
)
and it decays by emission of
-rays with energies of 396.1keV and 802.0keV. It is attributed to a 13/2 + state at E
* = 1198.1 keV.PACS:
23.60. + e
decay - 27.90. + b
相似文献
104.
105.
A method is proposed for designing a two-dimensional randomly rough Dirichlet surface that, when illuminated at normal incidence, scatters a scalar plane wave with a specified angular distribution of its intensity. The method is validated by computer simulation calculations. 相似文献
106.
A. N. Andreyev D. Ackermann F. P. Heßberger S. Hofmann M. Huyse I. Kojouharov B. Kindler B. Lommel G. Münzenberg R. D. Page K. Van de Vel P. Van Duppen K. Heyde 《The European Physical Journal A - Hadrons and Nuclei》2003,18(1):55-64
Alpha-decay of the new nuclide 184Bi has been studied in the complete-fusion reaction 93Nb(94Mo, 3n)184Bi at the velocity filter SHIP. The evaporation residues were separated in-flight and subsequently identified on the basis of recoil-
, recoil-
-
analysis and excitation functions measurements. Two
-decaying isomeric states in 184Bi with half-life values of 13(2) ms and 6.6(1.5) ms were identified. The
-branching ratio of 180Tl was deduced for the first time as
. Improved data on the fine-structure
-decay of 186Bi were obtained in the 93Nb(95Mo, 2n)186Bi reaction. A similarity of the decay energies and half-life values of 184,186Bi is pointed out and a possible explanation for this effect is suggested.Received: 14 March 2003, Revised: 29 April 2003, Published online: 2 September 2003PACS:
23.60.+e
decay - 27.70.+q
- 27.80.+w
K. Heyde: Present address: EP-ISOLDE, CERN, CH-1211, Geneva 23, Switzerland. 相似文献
107.
108.
J. Khuyagbaatar S. Hofmann F. P. Heßberger D. Ackermann S. Antalic H. G. Burkhard S. Heinz B. Kindler A. F. Lisetskiy B. Lommel R. Mann K. Nishio H. J. Schött B. Sulignano 《The European Physical Journal A - Hadrons and Nuclei》2007,34(4):355-361
Isomeric states in 214Th and 213Th were identified by means of γ -rays measured in delayed coincidence with the implanted evaporation residues. These were
produced in irradiations of 164Dy with 54Cr projectiles and separated in-flight by the velocity filter SHIP. An isomeric state of I
π = 8+ with a half-life of (1.24±0.12) μs was identified in 214Th . The configuration π[1h
9/2 ⊗ 2f
7/2] was assigned to this state. An isomeric state with a half-life of (1.4±0.4) μs was observed in 213Th . Tentatively it was assigned to an I
π = 13/2+ state. 相似文献
109.
Druzhinin SI Dubbaka SR Knochel P Kovalenko SA Mayer P Senyushkina T Zachariasse KA 《The journal of physical chemistry. A》2008,112(13):2749-2761
The newly synthesized aminobenzonitriles with two bulky amino substituents 4-(di-tert-butylamino)benzonitrile (DTABN) and 3-(di-tert-butylamino)benzonitrile (mDTABN) have strongly twisted amino groups in the ground state. From X-ray crystal analysis it is found that the amino twist angle theta of mDTABN equals 86.5 degrees , whereas a twist angle of around 75 degrees is deduced for DTABN from the extinction coefficient of its lowest-energy absorption band in n-hexane. Because of the electronic decoupling between the amino and benzonitrile groups caused by these large twist angles, the absorption of DTABN and mDTABN is relatively weak below 40000 cm-1, with extinction coefficients around 25 times smaller than those of the planar 4-(dimethylamino)benzonitrile (DMABN). DTABN as well as mDTABN undergo efficient intramolecular charge transfer (ICT) in the singlet excited state, in nonpolar (n-hexane) as well as in polar (acetonitrile) solvents. Their fluorescence spectra consist of an ICT emission band, without evidence for locally excited (LE) fluorescence. The occurrence of efficient ICT with mDTABN is different from the findings with all other N,N-dialkylaminobenzonitriles in the literature, for which ICT only appears with the para-derivative. From solvatochromic measurements, an ICT dipole moment of 17 D is determined for DTABN as well as for mDTABN, similar to that of DMABN. The picosecond fluorescence decays of DTABN (time resolution 3 ps) are effectively single exponential. Their decay time is equal to the ICT lifetime tau'0(ICT), which increases with solvent polarity from 0.86 ns in n-hexane to 3.48 ns in MeCN at 25 degrees C. The femtosecond excited-state absorption (ESA) spectra of DTABN in n-hexane and MeCN at 22 degrees C show a decay of the LE and a corresponding rise of the ICT absorption. The ICT reaction time is 70 fs in n-hexane and 60 fs in MeCN. DTABN and mDTABN may have a strongly twisted ICT state, similar to that of 6-cyanobenzoquinuclidine but different from that of DMABN. 相似文献
110.
Phosphoraneiminato Acetate Cluster of Copper and Zinc. Crystal Structures of [Cu4(NPEt3)2(O2CCH3)6] and [Zn4(NPEt3)2(O2CCH3)6] The anhydrous acetates of copper(II) and zinc react with the silylated phosphaneimine Me3SiNPEt3 in dichloromethane at 20 °C forming the mixed phosphoraneiminato acetate clusters [Cu4(NPEt3)2(O2CCH3)6] ( 1 ), which forms emerald crystals, and colourless [Zn4(NPEt3)2 · (O2CCH3)6] ( 2 ). In spite of analogous composition the structures of 1 and 2 are completely different. In the asymmetric unit of 1 three copper atoms of an almost isosceles triangle are linked via two nitrogen atoms of the NPEt3– groups to form a trigonal bipyramidal aggregate. One of these three copper atoms is chelated by an acetate group, another one is connected with the fourth copper atom via three μ2‐O2C–CH3 groups. The asymmetric units are associated via a μ2‐O2C–CH3 group and a μ3‐OC(O)CH3 group at a time so that infinite chains result. In 2 two zinc atoms are linked via the nitrogen atoms of the two NPEt3– groups to form an almost centrosymmetric four‐membered ring. Both nitrogen atoms of the four‐membered ring are connected with another zinc atom each. These zinc atoms again are linked with the zinc atoms of the Zn2N2 four‐membered ring via two μ2‐O2C–CH3 groups each and additionally coordinated with a terminal acetate ligand each. 相似文献