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81.
Hatsuhiko Harashina Toshio Nakane Takahito Itoh 《Journal of polymer science. Part A, Polymer chemistry》2007,45(11):2184-2193
Semiaromatic poly(ester amide)s (PEAs) were synthesized by the melt polycondensation of ethanolamine (EA) derivatives with dimethyl terephthalate and ethylene glycol in the presence of tetrabutyl titanate as a catalyst, and their crystallization and thermal properties were investigated. The introduction of an amide group into a semiaromatic polyester such as poly(ethylene terephthalate) (PET) produced PEAs (EA-modified PET polymers) with an increase in the melting point. However, these PEAs were found to decompose at a lower temperature than PET on the basis of TGA. Moreover, direct pyrolysis/mass spectrometry measurements suggested that an initial step of the thermal decomposition was a β-CH hydrogen-transfer reaction via asix-member ring transition state at the ester–ethylene–amide unit, at which carbon–oxygen bond scission took place to yield carboxyl and N-vinylamide end groups. Furthermore, molecular orbital calculations using trimer models bis[2-[[4-(methoxycarbonyl)benzoyl]oxy]ethyl]terephthalate, N-[2-[[4-(methoxycarbonyl)benzoyl]oxy]ethyl]-4-[2-[[4-(methoxycarbonyl)benzoyl]oxy]ethyloxycarbonyl]benzamide, and N,N′-bis[2-[[4-(methoxycarbonyl)benzoyl]oxy]ethyl]terephthalamide strongly supported the idea that the β-CH hydrogen-transfer reaction in the thermal decomposition of PEAs might occur more easily at the methylene group next to the amide group in an ester–ethylene–amide unit rather than at the methylene group next to the ester group in an ester–ethylene–ester unit. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2184–2193, 2007 相似文献
82.
Tsutom Hasuikea Toshihiko Hattori Toshio Hayashi Seiichi Wakaizumi 《Zeitschrift fur Physik C Particles and Fields》1997,76(1):127-132
Due to the large mass of top quark, CP violation in the top-quark decay is sensitive to the interactions mediated by Higgs bosons. We consider CP violation in t → W + b decay by calculating consistently in unitary gauge the CP-violating up-down asymmetry of the leptons from W boson decays in t → W + b, defined by Grz?dkowski and Gunion, in the two-Higgs doublet model with CP-violating neutral sector. The asymmetry is shown to be at most of the order of (1–4) × 10-4 for tan β = 1.0, where tan β is the ratio of vacuum expectation values for the two neutral Higgs bosons. 相似文献
83.
84.
Tetsuya Hattori 《Journal of statistical physics》2007,127(3):609-627
Let W(x,y) = ax
3+ bx
4+ f
5
x
5+ f
6
x
6+ (3 ax
2)2
y+ g
5
x
5
y + h
3
x
3
y
2 + h
4
x
4
y
2 + n
3
x
3
y
3+a
24
x
2
y
4+a
05
y
5+a
15
xy
5+a
06
y
6, and X = , , where the coefficients are non-negative constants, with a > 0, such that X
2(x,x
2)−Y(x,x
2) is a polynomial of x with non-negative coefficients.
Examples of the 2 dimensional map Φ: (x,y)↦ (X(x,y),Y(x,y)) satisfying the conditions are the renormalization group (RG) maps (modulo change of variables) for the restricted self-avoiding
paths on the 3 and 4 dimensional pre-gaskets.
We prove that there exists a unique fixed point (x
f
,y
f
) of Φ in the invariant set .
2000 Mathematics Subject Classification Numbers: 82B28; 60G99; 81T17; 82C41. 相似文献
85.
In this study, we propose a new Low-Reynolds-Number (LRN)one-equation model, which is derived from an LRN two-equation(k-ε) model. The derivation of the transport equation, in principle, is based on the assumption that the turbulent structure
parameter remains constant. However, the relation for the turbulent structure parameter a
1(=|−
|/k) is modified to account for near-wall turbulence. As a result, the present one-equation model contains a term which takes
the near-wall limiting behavior explicitly into account. Thus, the present model provides the correct wall-limiting behavior
of turbulence in the vicinity of the wall and can be applied to the analysis of heat transfer. The validity of the present
model is tested in channel flows, boundary layer flows with and without pressure gradient, plane wall jet, and flow with separation
and reattachment. The calculated results showed good agreement with the direct numerical simulation (DNS) and experimental
data.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
86.
Hideki Shimura Ryota Tanaka Yoshiaki Shimada Kazuo Yamashiro Nobutaka Hattori Takao Urabe 《BMC biochemistry》2017,18(1):14
Background
Peptides with cytoprotective functions, including antioxidants and anti-infectives, could be useful therapeutics. Carnosine, β-alanine-histidine, is a dipeptide with anti-oxidant properties. Tripeptides of Ala-His-Lys, Pro-His-His, or Tyr-His-Tyr are also of interest in this respect.Results
We synthesized several histidine-containing peptides including glycine or alanine, and tested their cytoprotective effects on hydrogen peroxide toxicity for PC12 cells. Of all these peptides (Gly-His-His, Ala-His-His, Ala-His-Ala, Ala-Ala-His, Ala-Gly-His, Gly-Ala-His (GAH), Ala-His-Gly, His-Ala-Gly, His-His-His, Gly-His-Ala, and Gly-Gly-His), GAH was found to have the strongest cytoprotective activity. GAH decreased lactate dehydrogenase (LDH) leakage, apoptosis, morphological changes, and nuclear membrane permeability changes against hydrogen peroxide toxicity in PC12 cells. The cytoprotective activity of GAH was superior to that of carnosine against hydrogen peroxide toxicity in PC12 cells. GAH also protected PC12 cells against damage caused by actinomycin D and staurosporine. Additionally, it was found that GAH also protected SH-SY5Y and Jurkat cells from damage caused by hydrogen peroxide, as assessed by LDH leakage.Conclusion
Thus, a novel tripeptide, GAH, has been identified as having broad cytoprotective effects against hydrogen peroxide-induced cell damage.87.
Urita K Shiga Y Fujimori T Iiyama T Hattori Y Kanoh H Ohba T Tanaka H Yudasaka M Iijima S Moriguchi I Okino F Endo M Kaneko K 《Journal of the American Chemical Society》2011,133(27):10344-10347
An outstanding compression function for materials preparation exhibited by nanospaces of single-walled carbon nanohorns (SWCNHs) was studied using the B1-to-B2 solid phase transition of KI crystals at 1.9 GPa. High-resolution transmission electron microscopy and synchrotron X-ray diffraction examinations provided evidence that KI nanocrystals doped in the nanotube spaces of SWCNHs at pressures below 0.1 MPa had the super-high-pressure B2 phase structure, which is induced at pressures above 1.9 GPa in bulk KI crystals. This finding of the supercompression function of the carbon nanotubular spaces can lead to the development of a new compression-free route to precious materials whose syntheses require the application of high pressure. 相似文献
88.
Morohashi N Noji S Nakayama H Kudo Y Tanaka S Kabuto C Hattori T 《Organic letters》2011,13(13):3292-3295
Powdery crystals of p-tert-butylthiacalix[4]arene (2) selectively include EtOH from 1:1 mixtures of MeOH-EtOH and EtOH-PrOH, and EtCO(2)H from HCO(2)H-EtCO(2)H. On the other hand, no acid is included from HCO(2)H-MeCO(2)H, even though MeCO(2)H is included from the neat acid. The origins of these phenomena are discussed based on X-ray analysis of inclusion crystals prepared separately by crystallization. 相似文献
89.
The enantioselective propargylic alkylation of propargylic esters with aldehydes in the presence of a copper complex and an optically active secondary amine as cocatalysts has been found to give the corresponding propargylic alkylated products in good yields as a mixture of two diastereoisomers with a high enantioselectivity. 相似文献
90.
The enantioselective propargylic amination of propargylic pentafluorobenzoates bearing an alkyl group at the propargylic position with amines in the presence of catalytic amounts of a copper complex and an optically active diphosphine such as BINAP has been found to give the corresponding propargylic amines in good yields with high enantioselectivity. 相似文献