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1.
A rapid microtiter plate assay for the detection of inhibitors of the Na+, K+-ATPase has been developed. The assay is based on the measurement of inorganic phosphate released from the substrate, ATP,
and has been designed to be carried out in the individual wells of a microtiter plate. Since the production of inorganic phosphate
is determined colorimetrically, multiple samples can be tested simultaneously using a microtiter plate reader. This microtiter
plate assay is particularly useful for screening large numbers of samples, such as microbial culture supernatants. 相似文献
2.
S. G. Yunusova S. D. Gusakova A. I. Glushenkova U. K. Nadzhimov Sh. Turabekov SA. Musaev 《Chemistry of Natural Compounds》1991,27(2):147-150
A comparative analysis has been made of the amounts of lipids and their fatty-acid compositions in the seeds of the lines of agenetic collection of cotton plants of the speciesGossypium hirsutum and their hybrids and the variety Tashkent-1. The results obtained on the fatty-acid compositions of some hybrids make it possible to recommend the use of individual lines of cotton plants as donors for improving the food-value indices of cottonseed oil.Institute of Chemsitry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. V. I. Lenin Tashkent State University. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 173–176, March–April, 1991. 相似文献
3.
Dr. Sara Sabater Dr. David Schmidt Dr. Heidi Schmidt Dr. Maximilian W. Kuntze-Fechner Dr. Thomas Zell Connie J. Isaac Dr. Nasir A. Rajabi Harry Grieve Dr. William J. M. Blackaby Dr. John P. Lowe Prof. Stuart A. Macgregor Dr. Mary F. Mahon Prof. Dr. Udo Radius Prof. Michael K. Whittlesey 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(52):13221-13234
The addition of PPh2H, PPhMeH, PPhH2, P(para-Tol)H2, PMesH2 and PH3 to the two-coordinate Ni0 N-heterocyclic carbene species [Ni(NHC)2] (NHC=IiPr2, IMe4, IEt2Me2) affords a series of mononuclear, terminal phosphido nickel complexes. Structural characterisation of nine of these compounds shows that they have unusual trans [H−Ni−PR2] or novel trans [R2P−Ni−PR2] geometries. The bis-phosphido complexes are more accessible when smaller NHCs (IMe4>IEt2Me2>IiPr2) and phosphines are employed. P−P activation of the diphosphines R2P−PR2 (R2=Ph2, PhMe) provides an alternative route to some of the [Ni(NHC)2(PR2)2] complexes. DFT calculations capture these trends with P−H bond activation proceeding from unconventional phosphine adducts in which the H substituent bridges the Ni−P bond. P−P bond activation from [Ni(NHC)2(Ph2P−PPh2)] adducts proceeds with computed barriers below 10 kcal mol−1. The ability of the [Ni(NHC)2] moiety to afford isolable terminal phosphido products reflects the stability of the Ni−NHC bond that prevents ligand dissociation and onward reaction. 相似文献
4.
用强子–弦级联模型JPCIAE及相应的Monte Carlo事例产生器研究相对论性核–核碰撞中带电粒子多重数的赝快度密度对能量和中心度的依赖关系.无需另调任何模型参数的条件下,此模型可以同时较好地描述相对论性pp实验数据及PHOBOS和PHENIX实验组的Au+Au实验数据.本文指出:因〈Npart〉并非严格定义的物理量,致使实验上和理论上确定〈Npart〉有一定任意性,从而使得每参加者核子对的带电粒子赝快度密度随着〈Npart〉的增加可能逐渐增大,也可能逐渐减小,因此用它来区分粒子产生机制是欠妥的. 相似文献
5.
6.
Davies DL Macgregor SA Poblador-Bahamonde AI 《Dalton transactions (Cambridge, England : 2003)》2010,39(43):10520-10527
Density functional theory calculations have been employed to model ethene hydroarylation using an [Ir(κ(2)-OAc)(PMe(3))Cp](+) catalyst, 1. The reaction proceeds via: (i) an acetate-assisted C-H activation of benzene via an AMLA-6 transition state; (ii) rate-limiting insertion of ethene into the Ir-Ph bond; and (iii) protonolysis of the β-phenylethyl species by HOAc. A range of competing processes are assessed, the most important of which are the C-H activation of ethene at 1 and trapping of the β-phenylethyl intermediate with ethene. The former process gives rise to Ir-vinyl species which can then access further ethene insertion to give stable allyl by-products. A comparison with other ethene hydroarylation catalysts reported in the literature is presented. 相似文献
7.
Suzanne Burling Dr. L. Jonas L. Häller Dr. Elena Mas‐Marzá Dr. Aitor Moreno Stuart A. Macgregor Prof. Mary F. Mahon Dr. Paul S. Pregosin Prof. Dr. Michael K. Whittlesey Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(41):10912-10923
The five‐coordinate ruthenium N‐heterocyclic carbene (NHC) hydrido complexes [Ru(IiPr2Me2)4H][BArF4] ( 1 ; IiPr2Me2=1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene; ArF=3,5‐(CF3)2C6H3), [Ru(IEt2Me2)4H][BArF4] ( 2 ; IEt2Me2=1,3‐diethyl‐4,5‐dimethylimidazol‐2‐ylidene) and [Ru(IMe4)4H][BArF4] ( 3 ; IMe4=1,3,4,5‐tetramethylimidazol‐2‐ylidene) have been synthesised following reaction of [Ru(PPh3)3HCl] with 4–8 equivalents of the free carbenes at ambient temperature. Complexes 1 – 3 have been structurally characterised and show square pyramidal geometries with apical hydride ligands. In both dichloromethane or pyridine solution, 1 and 2 display very low frequency hydride signals at about δ ?41. The tetramethyl carbene complex 3 exhibits a similar chemical shift in toluene, but shows a higher frequency signal in acetonitrile arising from the solvent adduct [Ru(IMe4)4(MeCN)H][BArF4], 4 . The reactivity of 1 – 3 towards H2 and N2 depends on the size of the N‐substituent of the NHC ligand. Thus, 1 is unreactive towards both gases, 2 reacts with both H2 and N2 only at low temperature and incompletely, while 3 affords [Ru(IMe4)4(η2‐H2)H][BArF4] ( 7 ) and [Ru(IMe4)4(N2)H][BArF4] ( 8 ) in quantitative yield at room temperature. CO shows no selectivity, reacting with 1 – 3 to give [Ru(NHC)4(CO)H][BArF4] ( 9 – 11 ). Addition of O2 to solutions of 2 and 3 leads to rapid oxidation, from which the RuIII species [Ru(NHC)4(OH)2][BArF4] and the RuIV oxo chlorido complex [Ru(IEt2Me2)4(O)Cl][BArF4] were isolated. DFT calculations reproduce the greater ability of 3 to bind small molecules and show relative binding strengths that follow the trend CO ? O2 > N2 > H2. 相似文献
8.
The helix-coil transition of poly[d(I-C)] and poly[d(A-T)] was studied as a function of hydrostatic pressure, temperature, and sodium ion concentration. These studies were undertaken in light of a recently published phase diagram for double stranded nucleic acids [Dubins et al. J. Am. Chem. Soc. 2001, 123, 9254-9259]. The sign and magnitude of the volume change for the heat-induced helix-coil transition, DeltaV(T), of poly[d(I-C)] and poly[d(A-T)] were dependent on the helix-coil transition temperature, T(M), at atmospheric pressure. The sign of DeltaV(T) changed from negative to positive as T(M) was increased by increasing the sodium ion concentration. For poly[d(I-C)], DeltaV(T) = 0 cm(3) mol(-1), when the sodium ion concentration is such that the spectroscopically monitored T(M) = 55 degrees C at atmospheric pressure. For poly[d(A-T)], the value of DeltaV(T) = 0 under conditions such that T(M) = 47 degrees C at atmospheric pressure. Negative values of DeltaV(T) imply that the helical form is destabilized at high pressure. Under experimental conditions where the DeltaV(T) for the transition is negative, the transition could be caused by increasing the pressure under isothermal conditions. At temperatures below T(M) measured at atmospheric pressure the midpoint of the pressure-induced helix-coil transition, P(M), decreases with increasing temperature. The volume change of the pressure-induced transitions helix-coil transition, DeltaV(P), was calculated assuming a two-state model. The magnitude of DeltaV(P) (per cooperative length) was much larger than the volume change (per base pair) measured for the heat-induced transition, DeltaV(T), calculated using the Clapeyron equation. The ratio of these two volume changes was used to calculate the cooperative length for the pressure-induced transition. This parameter depends strongly on temperature, becoming greater closer to T(M) measured at atmospheric pressure. At temperatures approaching T(M) the magnitude of the cooperative length of the pressure-induced transition is approximately twice that observed for the heat-induced transition (N(T)). On the basis of the temperature dependence of the DeltaV(T) for the two polymers the coefficient of thermal expansion of the two polymers was found to be 0.17 and 0.16 cm(3) K(-1) mol(-1) for poly[d(I-C)] and poly[d(A-T)], respectively. 相似文献
9.
The distributions of dynamic variables in the deep inelastic scattering (DIS) of heavy-ions are studied by a direct simulation technique based on the single-nucleon-transfer-mechanism. The relative motion of the two collision partners is described by a Lagrange equation, and the transition probability of a single nucleon during the interaction time is calculated by the statisti-cal spectroscopy method.The occurrence of the transition event and the corresponding change of the dynamic variables are both treated randomly according to the transition probability. The calculated results for the reaction of 40Ar+58Ni(EL=280MeV) are compared with experimental data. 相似文献
10.
Exploration for Degradation of Λ Polarization Produced in Relativistic Nucleus Nucleus Collisions 下载免费PDF全文
YE YunXiu CHEN Zhi RUAN TuNan SHEN Ji LV HaiJiang DONG WeiJiang SA BenHao TAI An 《中国物理C(英文版)》2000,24(2):125-130
The degradation of Λ transverse polarization produced in S+Pb central collisions at energy 200 GeV per nucleon has been studied in detail. The S+Pb central collision events have been generated using Monte-Carlo generator——LUCIAE at 200 GeV per nucleon. The various factors degrading Λ transverse polarization have been analysed quantitatively. The ratios of Λ′s produced from rescattering, secondary production and decays of Σ, Ξ hyperons to the total measurable Λ′s in experiment have been investigeted and the degradation effect of these Λ on the total polarization has been determined. The simulation and calculation show that above three factors decrease the Λ transverse polarization strongly, however, can not eliminate the polarization completely when the Λ′s are assumed to be produced from hadronic gas in the final state. To explan the experimental data of vanished Λ polarization, it probably needs to consider new mechanisms of Λ production, including a weak effect of QGP formation. 相似文献