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排序方式: 共有206条查询结果,搜索用时 46 毫秒
1.
Nobuaki Obata 《Acta Appl Math》1997,47(1):49-77
A general theory of operators on Boson Fock space is discussed in terms of the white noise distribution theory on Gaussian space (white noise calculus). An integral kernel operator is generalized from two aspects: (i) The use of an operator-valued distribution as an integral kernel leads us to the Fubini type theorem which allows an iterated integration in an integral kernel operator. As an application a white noise approach to quantum stochastic integrals is discussed and a quantum Hitsuda–Skorokhod integral is introduced. (ii) The use of pointwise derivatives of annihilation and creation operators assures the partial integration in an integral kernel operator. In particular, the particle flux density becomes a distribution with values in continuous operators on white noise functions and yields a representation of a Lie algebra of vector fields by means of such operators. 相似文献
2.
3.
T Nakao M Obata M Kawakami K Morita H Tanaka Y Morimoto S Takehara T Yakushiji T Tahara 《Chemical & pharmaceutical bulletin》1991,39(10):2556-2563
A series of 2-aryl-5,6-dihydro-(1)benzothiepino[5,4-c]pyridazin-3(2H)- ones and related compounds were synthesized and evaluated for their ability to displace 3H-diazepam from rat brain membranes in vitro, and to prevent bicuculline induced convulsions in mice in vivo. Compounds with a 4'-methoxyphenyl (36) or 4'-chlorophenyl group (37, 39--42) as 2-aryl substituents showed prominent activities in both the in vitro and in vivo tests. Among them, 2-(4'-chlorophenyl)-5,6-dihydro- (37) and 2-(4'-chlorophenyl)-5,6-dihydro-10-fluoro-(1)benzothiepino[5,4-c]+ ++pyridazin- 3(2H)-one 7-oxides (41) showed activity twice as potent as diazepam in an anticonflict test (Vogel type, rats) while exhibiting less muscle relaxation (rotarod test, mice) and augmentation of gamma-aminobutyric acid-induced chloride current (Icl) in isolated frog sensory neurones than diazepam. Compound 37 (Y-23684) was selected from this series as a candidate for further development. The structure-activity relationships are discussed. 相似文献
4.
We have optimized a method for the determination of intracellular glutathione by high-performance liquid chromatography, using fluorimetric detection. To minimize artifacts and provide an accurate determination of intracellular glutathione, cell extracts were prepared using extraction conditions specifically designed to inhibit autoxidation and enzymatic degradation of glutathione. The sensitivity of the method was enhanced by adjusting the dansyl chloride derivatization reaction with regard to parameters such as pH, reaction time and dansyl chloride concentration. Both oxidized and reduced forms of glutathione were quantified using the refined method in extracts of oxidatively stressed J774A.1 mouse macrophage cells and reflected an expected shift in cellular redox status. 相似文献
5.
Tanaka T Teramura K Arakaki K Funabiki T 《Chemical communications (Cambridge, England)》2002,(22):2742-2743
Photoassisted selective catalytic reduction of NO with ammonia (photo-SCR) at low temperature over irradiated TiO2 in a flow reactor was confirmed to proceed efficiently and the adsorbed ammonia reacted with NO under irradiation of TiO2. 相似文献
6.
S Odake T Okayama M Obata T Morikawa S Hattori H Hori Y Nagai 《Chemical & pharmaceutical bulletin》1991,39(6):1489-1494
To develop a potent and specific collagenase inhibitor, a series of tetrapeptidyl hydroxamic acids were synthesized, based on the previous findings with tripeptidyl derivatives (Chem. Pharm. Bull., 38, 1007-1011, 1990). Among the series of tetrapeptidyl derivatives synthesized, R-Gly-Pro-Leu-Ala-NHOH and R-Gly-Pro-D-Leu-D-Ala-NHOH were found to be highly specific and potent inhibitors against vertebrate collagenase with an IC50 of 10(-6) M order, where R stands for Boc or acyl group. Analysis of their structure-activity relationships showed a characteristic feature of the substrate-binding site of collagenase as follows: 1) the S1 subsite forms a shallow hydrophobic pocket, although glycine residue corresponds to the subsite of the natural collagen substrate: 2) the S2 subsite constitutes a bulky pocket with less requirement for hydrophobicity: 3) the S3 subsite preferentially accommodates Pro residue: and 4) the accommodation of the P4-P1 subsites of peptidyl collagenase inhibitor to the S4-S1 subsites is required to form a tight binding of its hydroxamic acid moiety to the zinc ion at the catalytic site of the enzyme. The introduction of an enantiometric dipeptide unit, D-Leu-D-Ala, to the P2-P1 subsites demonstrated an increased binding capacity to the extended S4-S1 subsites of collagenase, thus providing proteinase-resistant inhibitor. 相似文献
7.
Determination of chemical form of antimony in contaminated soil around a smelter using X-ray absorption fine structure. 总被引:1,自引:0,他引:1
Masaki Takaoka Satoshi Fukutani Takashi Yamamoto Masato Horiuchi Naoya Satta Nobuo Takeda Kazuyuki Oshita Minoru Yoneda Shinsuke Morisawa Tsunehiro Tanaka 《Analytical sciences》2005,21(7):769-773
Only limited information is available about the behavior of antimony (Sb) in contaminated soils. However, understanding the behavior of Sb in contaminated soils is important, because the toxicity or solubility of this element depends on its chemical state. In this study, we investigated the levels of Sb and the chemical forms of Sb in the soil around a smelter using X-ray absorption fine structure (XAFS) spectra. The highest Sb concentration in the contaminated soil was 2900 mg/kg dry soil. According to Sb-K edge X-ray absorption near edge (XANE) spectra, the Sb in the soil was in the form of Sb(V) compounds. The similarity of extended XAFS (EXAFS) spectra suggests that Sb speciation was independent of the sampling site, which indicates that Sb or Sb2O3 emitted from the smelter was converted into Sb(V) compounds in the soil. 相似文献
8.
Storr T Obata M Fisher CL Bayly SR Green DE Brudziñska I Mikata Y Patrick BO Adam MJ Yano S Orvig C 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,11(1):195-203
Seven discrete sugar-pendant diamines were complexed to the {M(CO)(3)}(+) ((99m)Tc/Re) core: 1,3-diamino-2-propyl beta-D-glucopyranoside (L(1)), 1,3-diamino-2-propyl beta-D-xylopyranoside (L(2)), 1,3-diamino-2-propyl alpha-D-mannopyranoside (L(3)), 1,3-diamino-2-propyl alpha-D-galactopyranoside (L(4)), 1,3-diamino-2-propyl beta-D-galactopyranoside (L(5)), 1,3-diamino-2-propyl beta-(alpha-D-glucopyranosyl-(1,4)-D-glucopyranoside) (L(6)), and bis(aminomethyl)bis[(beta-D-glucopyranosyloxy)methyl]methane (L(7)). The Re complexes [Re(L(1)-L(7))(Br)(CO)(3)] were characterized by (1)H and (13)C 1D/2D NMR spectroscopy which confirmed the pendant nature of the carbohydrate moieties in solution. Additional characterization was provided by IR spectroscopy, elemental analysis, and mass spectrometry. Two analogues, [Re(L(2))(CO)(3)Br] and [Re(L(3))(CO)(3)Br], were characterized in the solid state by X-ray crystallography and represent the first reported structures of Re organometallic carbohydrate compounds. Conductivity measurements in H(2)O established that the complexes exist as [Re(L(1)-L(7))(H(2)O)(CO)(3)]Br in aqueous conditions. Radiolabelling of L(1)-L(7) with [(99m)Tc(H(2)O)(3)(CO)(3)](+) afforded in high yield compounds of identical character to the Re analogues. The radiolabelled compounds were determined to exhibit high in vitro stability towards ligand exchange in the presence of an excess of either cysteine or histidine over a 24 h period. 相似文献
9.
Yutaka Hitomi Masakazu Higuchi Tsunehiro Tanaka Takuzo Funabiki 《Journal of molecular catalysis. A, Chemical》2005,240(1-2):207-213
We examined the oxygenative degradation of 4-chlorocatechol and 4-tert-butylcatechol catalyzed by iron(III)-tris(pyridin-2-yl)amine complex from the standpoint of repressing the formation of 4-chlorocatechol esters of the oxygenated products that causes the incomplete degradation of 4-chlorocatechol. Analysis of the products revealed that 4-chlorocatechol esters are formed by the reaction of muconic anhydride, which is the monooxygenated product, with catechols. It was found that the use of MeOH as the solvent instead of MeCN completely suppressed the catechol ester formation through the methanolysis of muconic anhydride, which greatly improves the degradation efficiency of 4-chlorocatechol. 相似文献
10.
A new shipboard analytical method for determining picomolar levels of manganese in seawater has been developed. The method is based on a combination of chelating resin column extraction and improved chemiluminescence (CL) detection in a closed flow system. In this method, manganese in sample solution is selectively collected on newly-developed iminodiacetate-immobilized chelating resin, and then eluted with acidic solution containing hydrogen peroxide. The resulting eluent is mixed with luminol solution and aqueous ammonia after removal of iron ions by a chelating resin column, and then the mixture is introduced into the CL cell. The manganese concentration is obtained from the CL intensity. The detection limit (3SD) of manganese is 5 pmol L–1 from 9 mL of seawater sample. The method was applied to seawater samples collected at the Okinawa Trough. 相似文献