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991.
Velayudhanachari Sivanandan Achari Raichel Mary Lopez Sanjeevapai Jayasree Aliyath Somasekaran Rajalakshmi 《国际化学动力学杂志》2019,51(3):215-231
The current study discusses application of the lanthanum ions (La3+) as an activating agent incorporated /immobilized into coconut shell–based granular activated carbon (GAC) for porosity development; subsequently, the carbon material is used for the adsorption of phenol from aqueous solutions. The new carbons were characterized using FTIR, XRD, CHNO, burn off, and carbon yield. The surface functional groups were determined by Boehm titration. The Brunauer–Emmett–Teller (BET) surface area of the carbons is 953 m2 g−1 (GACLa1073), 997 m2 g−1 (GAC383), and 973 m2 g−1 (GACO383). Langmuir, Freundlich, Dubinin–Radushkevich, and John–Sivanandan Achari (J-SA) isotherm models on the equilibrium isotherm data were examined for the new carbon-phenol system. It is found that the Langmuir isotherm fits better with a monolayer adsorption capacity, highest for GACLa1073 (387.59 mg g−1) followed by GAC383 (303.03 mg g−1) and GACO383 (197.62 mg g−1). Kinetic studies reveal that the adsorption system follows the pseudo–second-order kinetic model. Isotherm analysis by the phase change method of John-Sivanandan Achari (J-SA) isotherm gives a better insight into adsorption phenomena, which is accompanied by regeneration studies of carbon with >75% for GACLa1073 after three cycles. 相似文献
992.
Lee R. Collins Gabriele Hierlmeier Dr. Mary F. Mahon Dr. Ian M. Riddlestone Prof. Michael K. Whittlesey 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(8):3215-3218
The electrophilic character of free diamidocarbenes (DACs) allows them to activate inert bonds in small molecules, such as NH3 and P4. Herein, we report that metal coordinated DACs also exhibit electrophilic reactivity, undergoing attack by Zn and Cd dialkyl precursors to afford the migratory insertion products [(6‐MesDAC‐R)MR] (M=Zn, Cd; R=Et, Me; Mes=mesityl). These species were formed via the spectroscopically characterised intermediates [(6‐MesDAC)MR2], exhibiting barriers to migratory insertion which increase in the order MR2 = ZnEt2 < ZnMe2 < CdMe2. Compound [(6‐MesDAC‐Me)CdMe] showed limited stability, undergoing deposition of Cd metal, by an apparent β‐H elimination pathway. These results raise doubts about the suitability of diamidocarbenes as ligands in catalytic reactions involving metal species bearing nucleophilic ligands (M‐R, M‐H). 相似文献
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Flood AB Nicolalde RJ Demidenko E Williams BB Shapiro A Wiley AL Swartz HM 《Radiation measurements》2011,46(9):916-922
BACKGROUND: To prepare for a possible major radiation disaster involving large numbers of potentially exposed people, it is important to be able to rapidly and accurately triage people for treatment or not, factoring in the likely conditions and available resources. To date, planners have had to create guidelines for triage based on methods for estimating dose that are clinically available and which use evidence extrapolated from unrelated conditions. Current guidelines consequently focus on measuring clinical symptoms (e.g., time-to-vomiting), which may not be subject to the same verification of standard methods and validation processes required for governmental approval processes of new and modified procedures. Biodosimeters under development have not yet been formally approved for this use. Neither set of methods has been tested in settings involving large-scale populations at risk for exposure. OBJECTIVE: To propose a framework for comparative evaluation of methods for such triage and to evaluate biodosimetric methods that are currently recommended and new methods as they are developed. METHODS: We adapt the NIH model of scientific evaluations and sciences needed for effective translational research to apply to biodosimetry for triaging very large populations following a radiation event. We detail criteria for translating basic science about dosimetry into effective multi-stage triage of large populations and illustrate it by analyzing 3 current guidelines and 3 advanced methods for biodosimetry. CONCLUSIONS: This framework for evaluating dosimetry in large populations is a useful technique to compare the strengths and weaknesses of different dosimetry methods. It can help policy-makers and planners not only to compare the methods' strengths and weaknesses for their intended use but also to develop an integrated approach to maximize their effectiveness. It also reveals weaknesses in methods that would benefit from further research and evaluation. 相似文献
996.
We clarify the explicit structure of the Hurwitz quaternion order, which is of fundamental importance in Riemann surface theory and systolic geometry. 相似文献
997.
S. W. Annie Bligh Nick Choi Donovan St.C. Green Harry R. Hudson Catherine M. McGrath Mary McPartlin 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4)
Abstract α-Hydroxyiminophosphonic acid derivatives are widely known not only as intermediates in the synthesis of the important aminophosphonic acids,1,2 but also as phosphorylating agents,3 potential metalloenzyme inhibitors,4 and as compounds having fungicidal activity.5 In this work the scope of these compounds has been extended considerably by the synthesis of a number of novel dialkyl derivatives. Novel lanthanide (LaIII, PrIII, NdIII, GdIII and DyIII) and transition metal (CoII and NiIII) complexes of dialkyl α-hydroxyiminophosphonates (RO)2P(O)C(R')N(OH) where R = Et. Pri and R′ = Me, Et have been prepared and the NMR shift properties of the PrIII complex (R = Et; R′ = Et) indicate the potential of these compounds as NMR shift reagents for the analysis of geometric isomers.6,7 X-ray crystal structure analysis of [Ni(L1)2C12] (L1: R = Et; R′ = Et) shows a distorted cis octahedral coordination at the nickel atom giving two symmetry related diethyl-(E)-α-hydroxyiminopropanephosphonate ligands and two chlorine donors, and those of [Pr(L2)3Cl3] and [Nd(L2)2(NO3)3(H2O)] (L2: R = Pri; R′ = Et) show nine-coordination geometries with asymmetric bidentate and monodentate L2 bonding respectively. Thus the metal complexes show unusual coordination ambivalence, changing from symmetrically bidentate to asymmetrically bidentate and then to monodentate bonding modes, to accommodate the different steric requirements of the coordinating anions in facilitating neutral complex formation. 相似文献
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I. Wayan Mudianta Mary J. Garson Paul V. Bernhardt 《Acta Crystallographica. Section C, Structural Chemistry》2010,66(4):o176-o178
The polycyclic title compound {systematic name: (1S,16S,17S,31S)‐3,20‐diazatetracyclo[15.15.01,17.13,31.116,20]tetratriaconta‐6,8,23,25‐tetraene}, C32H52N2, has recently been isolated and characterized structurally, in solution by NMR spectroscopy and in the solid state by X‐ray crystallography. At 130 K the structure is monoclinic (P21, Z = 4) and comprises two molecules in the asymmetric unit with distinctly different conformations in the twelve‐C‐atom bridging chains. We report that, at 250 K, a phase change from monoclinic to orthorhombic (P22121, Z = 4) occurs. The higher‐temperature phase is structurally characterized herein at 293 K. The two different conformers resolved in the monoclinic low‐temperature form merge to give a single disordered molecule in the asymmetric unit of the high‐temperature phase. 相似文献