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991.
Soichiro Kyushin Masanobu Ikarugi Kazutoshi Takatsuna Midori Goto Hideyuki Matsumoto 《Journal of organometallic chemistry》1996,510(1-2):121-133
Dibenzo[b,e]-7,7,8,8-tetraalkyl-7,8-disilabicyclo[2.2.2]octa-2,5-dienes (1: R = tBuCH2; 2: R = iPr) were prepared by the reaction of ClR2SiSiR2Cl with lithium anthracenide in 1,2-dimethoxyethane (DME) at room temperature. The structure of 1 was determined by X-ray crystallography. Crystal data for 1: monoclinic, rC2/c, A = 12.941(2), B = 14.601(1), C = 35.109(6) Å, β = 94.957(7)°, V = 6609(2) Å3, Z= 8, R = 0.048, Rw = 0.053 for 4037 reflections. Compounds 1 and 2 show the bathochromic shift of 1La and 1Lb bands in UV spectra and exhibit considerably low oxidation potentials due to effective σ-π conjugation. Compounds 1 and 2 form charge-transfer complexes with tetracyanoethylene (TCNE). In the case of 1, the charge-transfer complex (1: TCNE = 2: 1) could be isolated as crystals and the structure was determined by X-ray crystallography. Crystal data for the 1-TCNE complex: monoclinic, C2/c, A= 10.267(2), b = 36.077(4), C = 20.022(4) Å, β = 100.680(8)°, V = 7288(2) Å3, Z = 4, R = 0.045, Rw = 0.077 for 4120 reflections. The action of transition metal chlorides on 2 resulted in [4+2] cycloreversion to form CliPr2SiSiiPr2Cl and anthracene. 相似文献
992.
Summary. Group 2B transition metal complexes of bis[N-(2,6-diisopropylphenyl)imino]acenaphthene (o,o-iPr2C6H3-BIAN), namely, [Hg(o,o-iPr2C6H3-BIAN)Cl2] (1), [Zn(o,o-iPr2C6H3-BIAN)2](ClO4)2 (2), and [Cd(o,o-iPr2C6H3-BIAN)2](ClO4)2 (3) have been synthesized and characterized. In complexes 2 and 3, IR, NMR, and conductivity measurements confirm the coordination of two (o,o-iPr2C6H3-BIAN) ligands to the metal center with two discrete perchlorate anions. X-Ray crystal structure of 1 indicates a distorted tetrahedral geometry with two nitrogen atoms from (o,o-iPr2C6H3-BIAN) ligand and two chloride atoms coordinating to the Hg(II) center. 相似文献
993.
Shinsaku Fujita 《Theoretical chemistry accounts》1995,91(5-6):291-314
Summary The concept of markaracter is proposed to discuss marks and characters for a group of finite order on a common basis. Thus, we consider a non-redundant set of dominant subgroups and a non-redundant set of dominant representations (SDR), where coset representations concerning cyclic subgroups are named dominant representations (DRs). The numbers of fixed points corresponding to each DR are collected to form a row vecter called a dominant markaracter (mark-character). Such dominant markaracters for the SDR are collected as a markaracter table. The markaracter table is related to a subdominant markaracter table of its subgroup so that the corresponding row of the former table is constructed from the latter. The data of the markaracter table are in turn used to construct a character table of the group, after each character is regarded as a markaracter and transformed into a multiplicity vector. The concept of orbit index is proposed to classify multiplicity vectors; thus, the orbit index of each DR is proved to be equal to one, while that corresonding to an irreducible representation is equal to zero. 相似文献
994.
Baker RJ Farley RD Jones C Mills DP Kloth M Murphy DM 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(10):2972-2982
Paramagnetic diazabutadienegallium(II or III) complexes, [(Ar-DAB)2Ga] and [{(Ar-DAB*)GaX}2] (X = Br or I; Ar-DAB = {N(Ar)C(H)}2, Ar = 2,6-diisopropylphenyl), have been prepared by reactions of an anionic gallium N-heterocyclic carbene analogue, [K(tmeda)][:Ga(Ar-DAB)], with either "GaI" or [MoBr2(CO)2(PPh3)2]. A related InIII complex, [(Ar-DAB*)InCl2(thf)], has also been prepared. These compounds were characterised by X-ray crystallography and EPR/ENDOR spectroscopy. The EPR spectra of all metal(III) complexes incorporating the Ar-DAB ligand, [(Ar-DAB(.))MX(2)(thf)(n)] (M = Al, Ga or In; X = Cl or I; n = 0 or 1) and [(Ar-DAB)2Ga], confirmed that the unpaired spin density is primarily ligand centred, with weak hyperfine couplings to Al (a = 2.85 G), Ga (a = 17-25 G) or In (a = 26.1 G) nuclei. Changing the N substituents of the diazabutadiene ligand to tert-butyl groups in the gallium complex, [(tBu-DAB*)GaI2] (tBu-DAB={N(tBu)C(H)}2), changes the unpaired electron spin distribution producing 1H and 14N couplings of 1.4 G and 8.62 G, while the aryl-substituted complex, [(Ar-DAB*)GaI2], produces couplings of about 5.0 G. These variations were also manifested in the gallium couplings, namely aGa approximately 1.4 G for [(tBu-DAB*)GaI2] and aGa approximately 25 G for [(Ar-DAB*)GaI2]. The EPR spectra of the gallium(II) and indium(II) diradical complexes, [{(Ar-DAB*)GaBr}2], [{(Ar-DAB*)GaI}2], [{(tBu-DAB*)GaI}2] and [{(Ar-DAB*)InCl}2], revealed doublet ground states, indicating that the Ga-Ga and In-In bonds prevent dipole-dipole coupling of the two unpaired electrons. The EPR spectrum of the previously reported complex, [(Ar-BIAN*)GaI2] (Ar-BIAN = bis(2,6-diisopropylphenylimino)acenaphthene) is also described. The hyperfine tensors for the imine protons, and the aryl and tert-butyl protons were obtained by ENDOR spectroscopy. In [(Ar-DAB*)GaI2], gallium hyperfine and quadrupolar couplings were detected for the first time. 相似文献
995.
996.
Takanori Soya Prof. Dr. Atsuhiro Osuka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(30):10639-10644
The metalation of meso‐tetrakis(pentafluorophenyl)‐substituted [26]rubyrin has been explored with Group 9 metal salts (RhI, CoII, IrIII), affording a Hückel aromatic [26]rubyrin–bis‐RhI complex with a highly curved gable‐like structure, a Hückel antiaromatic [24]rubyrin–bis‐CoII complex that displays intramolecular antiferromagnetic coupling between the two CoII ions (J=?4.5 cm?1), and two Cp*‐capped IrIII complexes; in one, the iridium metal sits on the [26]rubyrin frame with two Ir?N bonds, whereas the other has an additional Ir?C bond, although both IrIII complexes display moderate aromatic character. This work demonstrates characteristic metalation abilities of this [26]rubyrin toward Group 9 metals. 相似文献
997.
Charles E. Carraher Jr. Michael R. Roner Marian Ayoub Ryan Crichton Alisa Moric-Johnson Lindsey Miller 《高分子科学杂志,A辑:纯化学与应用化学》2016,53(6):328-334
Poly(ether esters) are rapidly synthesized in moderate yield employing the interfacial polycondensation reaction system from the reaction of alpha-cyano-4-hydroxycinnamic acid and Group IVB metallocenes. The products are high polymers. Infrared spectroscopy shows the formation of new bands derived from the M-O and M-O(CO) linkages. It also shows that the products exist as alternating M-O and M-O(CO) linkages. The products show outstanding inhibition of a variety of cancer cell lines including two pancreatic cancer cell lines. EC50 values for the polymers are in the nanogram/mL range. The ability to inhibit the cancer cell lines is generally Hf>Zr>Ti. Thus, future synthesis and testing might consider using compounds containing hafnocene and zirconocene in addition to the titanocene moiety. 相似文献
998.
Dr. Paul Niklas Ruth Julijan Sarcevic Dr. Regine Herbst-Irmer Prof. Dr. Christian P. Sindlinger Prof. Dr. Dietmar Stalke 《Angewandte Chemie (International ed. in English)》2023,62(21):e202301609
The solid-state structure of decamethylsilicocene Cp*2Si with a bent and a linear molecule in the same unit cell was so far considered an exception in relation to the structures of its all-bent heavier analogues Cp*2E with E=Ge, Sn, Pb. Here, we present the solution to this conundrum by reporting a low-temperature phase, where all three symmetrically independent molecules are present in a bent formation. This reversible enantiotropic phase transition occurs in the temperature range between 80 K and 130 K and provides a rationale for the unexpected linear molecule based in entropy beyond hand-waving explanations such as electronic reasons or packing effects. 相似文献
999.
Dr. Rui Wei Xin-Feng Wang Dr. David A. Ruiz Prof. Dr. Liu Leo Liu 《Angewandte Chemie (International ed. in English)》2023,62(15):e202219211
Under an atmosphere of carbon monoxide (CO), a (phosphino)diazomethyl anion salt [[P]-CN2][K(18-C-6)(THF)] ( 1 ) ([P]=[(CH2)(NDipp)]2P; 18-C-6=18-crown-6; Dipp=2,6-diisopropylphenyl) undergoes a facile N2/CO exchange reaction giving the (phosphino)ketenyl anion salt [[P]-CCO][K(18-C-6)] ( 2 ). Oxidation of 2 with elemental Se affords the (selenophosphoryl)ketenyl anion salt [P](Se)-CCO][K(18-C-6)] ( 3 ). These ketenyl anions feature a strongly bent geometry at the P-bound carbon and this carbon atom is highly nucleophilic. The electronic structure of the ketenyl anion [[P]-CCO]− of 2 is examined by theoretical studies. Reactivity investigations demonstrate 2 as a versatile synthon for derivatives of ketene, enolate, acrylate and acrylimidate moieties. 相似文献
1000.
Puneeth Kumar Someswara Ashwathappa Takuya Higashi Vincent Desrosiers Alvaro A. Omaña Frédéric-Georges Fontaine 《Angewandte Chemie (International ed. in English)》2023,62(39):e202309295
The borylation of Csp3−H bonds is a challenging transformation that is typically restricted to transition metal catalysis. Herein, we report the site-selective metal-free Csp3−H borylation of saturated cyclic amines. It is possible to selectively borylate piperidine derivatives at the α or β positions according to the reaction conditions. The mechanism was supported by NMR spectroscopy, calorimetry experiments and density functional theory (DFT) computations. It suggests that the piperidine is dehydrogenated by complexation with BBr3 to produce an enamine intermediate, which is in turn borylated at either the α or β position according to the reaction conditions. 相似文献