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101.
Condensation of uracil derivatives (1,3,4) with acetone in the presence of triethylamine gave pyranopyrimidines (2,5,6). 相似文献
102.
We report an exceptionally mild, general and efficient copper catalyzed cross coupling reaction of aryl bromides and thiols using 0.5 mol % CuI and 1 mol % benzotriazole. Experimental simplicity, generality, functional group tolerance and low cost of the catalyst are advantages of the protocol. 相似文献
103.
N. Aggarwal B. Singh A. K. Bhati Renu Bala S. C. Bedi H. S. Hans 《Hyperfine Interactions》1983,13(1-3):271-274
Integral perturbed angular correlation technique has been used to measure the internal hyperfine magnetic fields at Hf nuclei in Fe, Co and Ni matrices. These represent a consistent set of measurements with diffused sources. The 9+/2 (208 keV) 9?/2 (113 keV) 7?/2 cascade in the decay of177Lu→177Hf was used for measurements. The results obtained are: $$\begin{gathered} H_{Fe}^{Hf} = - 266 \pm 47 kG, \hfill \\ H_{Co}^{Hf} = - 116 \pm 18 kG, \hfill \\ H_{Ni}^{Hf} = - 118 \pm 26 kG. \hfill \\ \end{gathered} $$ These measurements are compared with previous results and discussed in terms of methods of source preparation. 相似文献
104.
Rajendran T Manimaran B Liao RT Lin RJ Thanasekaran P Lee GH Peng SM Liu YH Chang IJ Rajagopal S Lu KL 《Inorganic chemistry》2003,42(20):6388-6394
A series of neutral luminescent molecular rectangles [[Re(CO)(3)(mu-bpy)Br][Re(CO)(3)(mu-L)Br]](2) (1-4) having fac-Re(CO)(3)Br as corners and 4,4'-bipyridine (bpy) as the bridging ligand on one side and other bipyridyl ligands of varying length (L) on the other side have been synthesized and characterized. The crystal structure of 1 shows a rectangular cavity with the dimensions of 11.44 x 7.21 A. When the cavity size is tuned from 1 to 4, a dimension of 11.4 x 20.8 A could be achieved, as revealed by the molecular modeling. These rectangles exhibit luminescence in solution at room temperature. In particular, compound 4 containing 1,4-bis(4'-pyridylethynyl)benzene (bpeb) as bridging ligand shows the excited-state lifetime of 495 ns. Fine-tuning of the cavity size of the rectangles improves their excited-state properties. These properties facilitate the study of excited-state electron-transfer reactions with electron acceptors and donors and host-guest binding. Crystallographic information: 1.6CH(3)COCH(3) is monoclinic, P2(1)/c, with a = 12.0890(2), b = 24.2982(2), and c = 12.8721(2) A, beta = 107.923(1) degrees, and Z = 2. 相似文献
105.
106.
Samata E. Shetgaonkar Ritu Mamgain Kotaro Kikushima Toshifumi Dohi Fateh V. Singh 《Molecules (Basel, Switzerland)》2022,27(12)
The chemistry of polyvalent iodine compounds has piqued the interest of researchers due to their role as important and flexible reagents in synthetic organic chemistry, resulting in a broad variety of useful organic molecules. These chemicals have potential uses in various functionalization procedures due to their non-toxic and environmentally friendly properties. As they are also strong electrophiles and potent oxidizing agents, the use of hypervalent iodine reagents in palladium-catalyzed transformations has received a lot of attention in recent years. Extensive research has been conducted on the subject of C—H bond functionalization by Pd catalysis with hypervalent iodine reagents as oxidants. Furthermore, the iodine(III) reagent is now often used as an arylating agent in Pd-catalyzed C—H arylation or Heck-type cross-coupling processes. In this article, the recent advances in palladium-catalyzed oxidative cross-coupling reactions employing hypervalent iodine reagents are reviewed in detail. 相似文献
107.
Vikas Mishra Vijaya Lakshmi Nag Ritu Tandon Shally Awasthi 《Applied biochemistry and biotechnology》2010,160(8):2322-2331
Management of rotavirus diarrhoea cases and prevention of nosocomial infection require rapid diagnostic method at the patient
care level. Diagnostic tests currently available are not routinely used due to economic or sensitivity/specificity constraints.
Agarose-based sieving media and running conditions were modulated by using central composite design and response surface methodology
for screening and electropherotyping of rotaviruses. The electrophoretic resolution of rotavirus genome was calculated from
input parameters characterising the gel matrix structure and running conditions. Resolution of rotavirus genome was calculated
by densitometric analysis of the gel. The parameters at critical values were able to resolve 11 segmented rotavirus genome.
Better resolution and electropherotypic variation in 11 segmented double-stranded RNA genome of rotavirus was detected at
1.96% (w/v) agarose concentration, 0.073 mol l−1 ionic strength of Tris base–boric acid–ethylenediamine tetraacetic acid buffer (1.4×) and 4.31 h of electrophoresis at 4.6 V cm−1 electric field strength. Modified agarose gel electrophoresis can replace other methods as a simplified alternative for routine
detection of rotavirus where it is not in practice. 相似文献
108.
Tarlok Singh Lobana Mani Kaushal Robin Bhatia Ritu Bala Ray J. Butcher Jerry P. Jasinksi 《Acta Crystallographica. Section C, Structural Chemistry》2022,78(1):30-35
In this investigation, the crystal structures of the thio-ligands 3-formylpyridine 4-phenylthiosemicarbazone (C13H12N4S, 1 ) and 4-benzoylpyridine 4-ethylthiosemicarbazone (C15H16N4S, 2 ), and of two new coordination compounds, chlorido(3-formylpyridine 4-phenylthiosemicarbazone-κS)bis(triphenylphosphane-κP)copper(I) acetonitrile monosolvate, [CuCl(C13H12N4S)(C18H15P)2]·CH3CN, 3 , and bis(3-formylpyridine 4-ethylthiosemicarbazonato-κ2N1,S)nickel(II), [Ni(C9H11N4S)2], 4 , are reported. In complex 3 , the thio-ligand coordinates in a neutral form to the Cu atom through its S-donor atom, and in complex 4 , the anionic thio-ligand chelates to the Ni atom through N- and S-donor atoms. The geometry of complex 3 is distorted tetrahedral [bond angles 99.70 (5)–123.23 (5)°], with the P—Cu—P bond angle being the largest, while that of complex 4 is square planar, with trans-S—Ni—S and N—Ni—N bond angles of 180°. 相似文献
109.
Bala Subramaniam 《Coordination chemistry reviews》2010,254(15-16):1843-1853
Employing a multiscale systems-based research approach, chemists and chemical engineers at the Center for Environmentally Beneficial Catalysis (CEBC) are collaboratively addressing major grand challenges facing the sustainable manufacture of fuels and chemicals from both traditional and renewable feedstocks. By judiciously combining the principles of green chemistry and green reactor engineering, augmented by valuable insights from industrial partners, CEBC researchers are developing alternative technology concepts that minimize the environmental footprint of chemical manufacturing processes including the reduction of carbon emissions. Such collaborations have resulted in several remarkable discoveries as follows: CO2-expanded liquids (CXLs) as reaction media for selective and inherently safe O2 oxidations including that for terephthalic acid production from p-xylene with potentially reduced solvent burning (i.e., reduced carbon footprint); propylene oxide production with environmentally benign solvents and oxidant, exploiting the compressibility of propylene at ambient temperatures for process intensification; a novel pressure-intensified ethylene oxide process virtually eliminating CO2 formation as a byproduct; highly selective hydroformylation of higher olefins employing CXLs and soluble polymer-supported homogeneous Rh-based catalysts that are easily retained in solution while the product is isolated by membrane filtration; and creation of nanoparticles of transition metal complexes with unique functional properties such as reversible oxygen binding and room-temperature nitric oxide disproportionation. Quantitative economic and environmental impact analyses have been employed to benchmark CEBC's novel technology concepts against conventional processes and to guide research and development. Examples of such advances in green processing are discussed in this review. 相似文献
110.
M. Roy S. K. Barbar P. Dave S. Jangid Indu Bala 《Applied Physics A: Materials Science & Processing》2010,100(4):1191-1196
Polycrystalline ceramic samples of fresnoite (Ba2TiSi2O8 or BTS) have been prepared by a standard solid-state reaction method using high-purity oxides and carbonates. For one set
of compounds, in stoichiometric ratio BaCO3, TiO2 and SiO2 were melted at 1300°C and then sintered into pellet form, whereas the other set of compounds have been prepared without melting
and sintered into pellet form at 1250°C. The formation of the single-phase compound and its structural parameters were investigated
by X-ray diffraction followed by Rietveld refinement and scanning electron microscopic (SEM) techniques. A better agreement
between the observed and calculated X-ray diffraction patterns was obtained by performing the Rietveld refinement with a structural
model using the non-centrosymmetric space group P4bm. A better agreement between observed and calculated d-values shows that
the lattice parameters calculated using the Rietveld refinement analysis are better than that of the earlier report so far.
The activation energies of both compounds were calculated by measuring its dc electrical conductivities. The results are discussed
in detail. 相似文献