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991.
Zhen‐Guo Zhao Xiao‐Yuan Wu Quan‐Guo Zhai Li‐Juan Chen Quan‐Zheng Zhang Wei Li Yi‐Ming Xie Can‐Zhong Lu 《无机化学与普通化学杂志》2008,634(2):288-294
Three new nickel(II) complexes constructed with N‐(2‐hydroxybenzyl)‐β‐alanine (H2L), namely [NiL(phen)H2O]·H2O ( 1 ) (phen = 1.10‐phenanthroline), [Ni4L4(H2O)4]·5H2O ( 2 ) and K[Ni4L4(NCS)(H2O)5]·5.42H2O ( 3 ) have been synthesized and characterized by single‐crystal X‐ray diffraction analysis. Complex 1 exhibits a discrete structure, and the structures are bound together through hydrogen bonding to a one‐dimensional chain in ladder‐like fashion. Complexes 2 and 3 contain similar [Ni4(μ2‐O)6] cores with “zig‐zig” arrangement. In complex 3 , the tetranuclear nickel units [Ni4L4(H2O)4] and [Ni4L4(NCS)(H2O)] are alternately bridged by potassium atoms to a one‐dimensional chain. The neighboring chains are further linked up by {K2O2} units to a two‐dimensional layer structure. Moreover, the IR, XRD, TGA and the temperature‐dependent magnetic susceptibility for 2 and 3 have also been studied. 相似文献
992.
Prof. Dr. Biplab Maji Prof. Dr. Xin-Hua Duan Patrick M. Jüstel Dr. Peter A. Byrne Dr. Armin R. Ofial Prof. Dr. Herbert Mayr 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(44):11367-11376
Rate constants for the reactions of dialkyl chalcogenides with laser flash photolytically generated benzhydrylium ions have been measured photometrically to integrate them into the comprehensive benzhydrylium-based nucleophilicity scale. Combining these rate constants with the previously reported equilibrium constants for the same reactions provided the corresponding Marcus intrinsic barriers and made it possible to quantify the leaving group abilities (nucleofugalities) of dialkyl sulfides and dimethyl selenide. Due to the low intrinsic barriers, dialkyl chalcogenides are fairly strong nucleophiles (comparable to pyridine and N-methylimidazole) as well as good nucleofuges; this makes them useful group-transfer reagents. 相似文献
993.
1 INTRODUCTION The complexes of amino acid Schiff base have attracted considerable attention because of their bio- activities[1, 2]. Taurine is a special amino acid in be- ings, and recently the complexes of taurine conden- sation salicylaldehyde Schiff … 相似文献
994.
1 INTRODUCTION Schiff base complexes containing sulfur and com- plexes of amino acid Schiff bases[1~5] have recently aroused increasing interest because of their antiviral, anticancer and antibacterial activities. Taurine, an amino acid containing sulfur, is indispensable to human beings and has important physiological func- tions. Recently, we have found that the Shiff base derived from taurine has manifold coordination modes[4~10]. Aromatic-ring stacking interaction is an important … 相似文献
995.
Ureidopeptide‐Based Brønsted Bases: Design,Synthesis and Application to the Catalytic Enantioselective Synthesis of β‐Amino Nitriles from (Arylsulfonyl)acetonitriles 下载免费PDF全文
Dr. Saioa Diosdado Dr. Rosa López Prof. Dr. Claudio Palomo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(21):6526-6531
The addition of cyanoalkyl moieties to imines is a very attractive method for the preparation of β‐amino nitriles. We present a highly efficient organocatalytic methodology for the stereoselective synthesis of β‐amino nitriles, in which the key to success is the use of ureidopeptide‐based Brønsted base catalysts in combination with (arylsulfonyl)acetonitriles as synthetic equivalents of the acetonitrile anion. The method gives access to a variety of β‐amino nitriles with good yields and excellent enantioselectivities, and broadens the stereoselective Mannich‐type methodologies available for their synthesis. 相似文献
996.
《Journal of Coordination Chemistry》2012,65(15):2506-2514
The mononuclear cobalt(III) complex [Co(L)2]Cl ·?H2O (1) (where L is H2N(CH2)2N=CC6H3(OMe)(O?)) has been prepared and characterized by IR, UV-Vis spectroscopy, conductivity measurements, elemental analysis, TGA, cyclic voltammetry and an X-ray structure determination. The cobalt(III) coordination sphere in [Co(L)2] is cis-CoN4O2 with the NNO ligands. Electrochemical studies of 1 using cyclic voltammetry indicate an irreversible cathodic peak (E pc, ca ?0.60 V) corresponding to reduction of cobalt(III) to cobalt(II). 相似文献
997.
998.
999.
Dr. Abuzar Khan Dr. Asma M. Elsharif Dr. Aasif Helal Prof. Zain H. Yamani Dr. Abbas Saeed Hakeem Dr. Mohd Yusuf Khan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(43):11132-11140
Mixed-matrix membranes (MMMs) with combination of two distinct dimensional nanofillers (such as 1D-3D, 2D-3D, or 3D-3D, etc.) have drawn special attention for gas separation applications due to their concerted effects on gas permeation and mechanical properties. An amine-functionalized 1D multiwalled carbon nanotube (NH2-MWCNT) with exceptional mechanical strength and rapid gas transport was crosslinked with an amine-functionalized 3D metal-organic framework (UiO-66-NH2) with high CO2 affinity in a Schiff base reaction. The resultant crosslinked mixed-dimensional nanostructure was used as a nanofiller in a polysulfone (PSf) polymer matrix to explore the underlying synergy between 1D and 3D nanostructures on the gas separation performance of MMMs. Cross-sectional scanning electron microscopy and mapping revealed the homogenous dispersion of UiO-66@MWCNT in the polymer matrix. The MMM containing 5.0 wt. % UiO-66@MWCNT demonstrated a superior permeability 8.3 Barrer as compared to the 4.2 Barrer of pure PSf membrane for CO2. Moreover, the selectivity (CO2/CH4) of this MMM was enhanced to 39.5 from the 28.0 observed for pure PSf under similar conditions of pressure and temperature. 相似文献
1000.
Erica C. Mitchell Mark E. Wolf Dr. Justin M. Turney Prof. Henry F. Schaefer III 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(58):14461-14471
Pnictinidenes are an increasingly relevant species in main group chemistry and generally exhibit proclivity for the triplet electronic ground state. However, the elusive singlet electronic states are often desired for chemical applications. We predict the singlet-triplet energy differences (ΔEST=ESinglet−ETriplet) of simple group 15 and 16 substituted pnictinidenes (Pn−R; Pn=P, As, Sb, or Bi) with highly reliable focal-point analyses targeting the CCSDTQ/CBS level of theory. The only cases we predict to have favorable singlet states are P−PH2 (−3.2 kcal mol−1) and P−NH2 (−0.2 kcal mol−1). ΔEST trends are discussed in light of the geometric predictions as well as qualitative natural bond order analysis to elucidate some of the important electronic structure features. Our work provides a rigorous benchmark for the ΔEST of fundamental Pn−R moieties and provides a firm foundation for the continued study of heavier pnictinidenes. 相似文献