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Dr. Konrad Viehrig Dr. Frank Surup Dr. Carsten Volz Dr. Jennifer Herrmann Dr. Antoine Abou Fayad Sebastian Adam Dr. Jesko Köhnke Prof. Dr. Dirk Trauner Prof. Dr. Rolf Müller 《Angewandte Chemie (International ed. in English)》2017,56(26):7407-7410
Secondary metabolome mining efforts in the myxobacterial multiproducer of natural products, Chondromyces crocatus Cm c5, resulted in the isolation and structure elucidation of crocagins, which are novel polycyclic peptides containing a tetrahydropyrrolo[2,3-b]indole core. The gene cluster was identified through an approach combining genome analysis, targeted gene inactivation in the producer, and in vitro experiments. Based on our findings, we developed a biosynthetic scheme for crocagin biosynthesis. These natural products are formed from the three C-terminal amino acids of a precursor peptide and thus belong to a novel class of ribosomally synthesized and post-translationally modified peptides (RiPPs). We demonstrate that crocagin A binds to the carbon storage regulator protein CsrA, thereby inhibiting the ability of CsrA to bind to its cognate RNA target. 相似文献
85.
The last two decades have seen a dramatic development in the study of metal-metal multiple bonds, particular successes being recorded in the field of organometallic chemistry. Syntheses designed to produce novel transition metal complexes with single, double, triple and quadruple metal-metal bonds occupy a most important place in such research, as also do reactivity studies. A striving to establish general principles has provided much of the motivation for such work, but one less obvious goal—the commercial application of the catalytic properties of metal-metal multiple bonding systems, in the medium and long term—should not be overlooked. All aspects of the investigations of metal-metal multiple bonds also apply to a particular class of compound that has, however, enjoyed little lime-light and thus deserves the present review: complexes with multiple bonds between transition metals and substituent-free (“bare”) main group elements. Although based mostly on accidental discoveries, the few noteworthy examples are now beginning to unfold general concepts of synthesis that are capable of being extended and thus are deserving of exploitation in preparative chemistry. The availability of further structural patterns exhibiting multiple bonds between transition metals and ligand-free main group elements might enable preparative organometallic chemistry to expand in a completely new direction (for instance by the stabilizing or activation of small molecules at the metal complex). This essay discusses the chemistry of complexes of bare carbon, nitrogen, and oxygen ligands (carbido-, nitrido-, and oxo-complexes) and their relationships to higher homologues from both a synthetic and a structural point of view. 相似文献
86.
H. Herrmann H.-W Jacobi G. Raabe A. Reese R. Zellner 《Fresenius' Journal of Analytical Chemistry》1996,355(3-4):343-344
Nitrate radical (NO3) reactions with benzene (R-1), toluene (R-2), p-xylene (R-3), p-cresol (R-4) and mesitylene (R-5) have been studied by laser photolysis/long path laser absorption (LP-LPLA) in aqueous solution. Rate constants of k1=(4.0±0.6) 108, k2=(1.2±0.3)109, k3=(1.6±0.1)109, k4= (8.4±2.3)108 and k5=(1.3±0.3)109 lmol-1s-1 were obtained at T=298 K. In addition, reaction rate coefficients for SO-5+Fe2+prod. (R-6) and SO-5+Mn2+prod. (R-7) of k6=(4.3±2.4) 107 lmol-1s-1 and k7=(4.6±1.0)106 lmol-1s-1 (T=298 K, I0) have been obtained by the application of laser photolysis/UV-VIS broadband diode array spectroscopy. A new laser photolysis/UV-long path laser absorption experiment has been applied to study the reaction of the Cl-2 radical anion with dissolved sulfur(IV). For the reactions Cl-2+HSO-32Cl-+H++SO-3 (R-8) and Cl-2+SO2-32Cl-+SO-3 (R-9) rate coefficients of k8=(1.7±0.2)108 lmol-1s-1 (T=298 K, I0) and of k9=(6.2±0.3)107 lmol-1s-1 (T=279 K, I0) were obtained. 相似文献
87.
Wolfgang A. Herrmann Gerhard M. Lobmaier Martina Elison 《Journal of organometallic chemistry》1996,520(1-2):231-234
Oxometal complexes of molybdenum and tungsten in high oxidation states from stable adducts with 1,3-dimethylimidazoline-2-ylidene (L) 1. The first ‘carbene’ complexes of molybdenum(VI) [MoO2Cl(L)3]Cl (3a) and tungsten(VI) WO2Cl2(L)2 (4b) are reported. 相似文献
88.
Herrmann H Jacobi HW Raabe G Reese A Zellner R 《Analytical and bioanalytical chemistry》1996,355(3-4):343-344
Nitrate radical (NO(3)) reactions with benzene (R-1), toluene (R-2), p-xylene (R-3), p-cresol (R-4) and mesitylene (R-5) have been studied by laser photolysis/long path laser absorption (LP-LPLA) in aqueous solution. Rate constants of k(1)=(4.0+/-0.6). 10(8), k(2)=(1.2+/-0.3). 10(9), k(3)=(1.6+/-0.1). 10(9), k(4)= (8.4+/-2.3). 10(8) and k(5)=(1.3+/-0.3). 10(9) lmol(-1)s(-1) were obtained at T=298 K. In addition, reaction rate coefficients for SO(-)(5)+Fe(2+)-->prod. (R-6) and SO(-)(5)+Mn(2+)-->prod. (R-7) of k(6)=(4.3+/-2.4). 10(7) lmol(-1)s(-1) and k(7)=(4.6+/-1.0). 10(6) lmol(-1)s(-1) (T=298 K, I-->0) have been obtained by the application of laser photolysis/UV-VIS broadband diode array spectroscopy. A new laser photolysis/UV-long path laser absorption experiment has been applied to study the reaction of the Cl(-)(2) radical anion with dissolved sulfur(IV). For the reactions Cl(-)(2)+HSO(-)(3)-->2Cl(-)+H(+)+SO(-)(3) (R-8) and Cl(-)(2)+SO(2-)(3)-->2Cl(-)+SO(-)(3) (R-9) rate coefficients of k(8)=(1.7+/-0.2). 10(8) lmol(-1)s(-1) (T=298 K, I-->0) and of k(9)=(6.2+/-0.3). 10(7) lmol(-1)s(-1) (T=279 K, I-->0) were obtained. 相似文献
89.
Jeanne Crassous Jos Rivera Nicolette S. Fender Lianhe Shu Luis Echegoyen Carlo Thilgen Andreas Herrmann Franois Diederich 《Angewandte Chemie (International ed. in English)》1999,38(11):1613-1617
The pure enantiomers of D 2 -C 84 as well as a third constitutional isomer of this higher fullerene were produced by a retro-Bingel reaction on the first organic derivatives of C84 (see scheme). These derivatives were synthesized by Bingel cyclopropenation of C84, separated, and unambiguously structurally characterized. 相似文献
90.
Horst Schneider Gerd T. Puchta Franz A. R. Kaul Gabriele Raudaschl-Sieber Frdric Lefebvre Guillaume Saggio Dimitrios Mihalios Wolfgang A. Herrmann Jean Marie Basset 《Journal of molecular catalysis. A, Chemical》2001,170(1-2):127-141
The modification of a mesoporous silica surface with Si(Ind)(CH3)2Cl and the immobilization of CpZr(NMe2)3 on this surface was studied via IR-spectroscopy. To reduce side reactions, the indenyl-modified silica was reacted with hexamethyldisilazane (HMDS) under IR-control before the CpZr(NMe2)3-immobilization. The role of the hydroxyl group protection with HMDS is discussed. The surface modifications have been repeated via Schlenk technique at the same conditions and the surface modifications were studied with 13C CP MAS–NMR, 1H MAS–NMR, elemental-, SEM- and BET-analysis. The surface species of the resulting catalysts are discussed. The precatalysts have been treated with methylaluminoxane (MAO) (Al:Zr (mol:mol)=500:1) and the resulting Zr contents (leaching-effect) are discussed. All catalysts have been tested in ethylene and propylene polymerization. 相似文献