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991.
The malonato-bridged copper(II) complex [Cu(mal)(H2O)(azpy)1/2] · H2O (1) (mal = malonate, azpy = 4,4′-azobispyridine) has been synthesized and characterized by X-ray diffraction. The structure of 1 consists of malonato-bridged uniform copper(II) chains which are covalent connected through azpy to form two-dimensional wavelike network. The magnetic pathway of complex 1 is through a single syn-anti carboxylate bridge connecting equatorial and equatorial positions of adjacent copper(II) atoms, and have the value of the intrachain ferromagnetic coupling (J = 8.73(3) cm−1) and interchain antiferromagnetic coupling (zJ′ = − 1.31(1) cm−1) through a numerical expression for a ferromagnetic uniform chain. 相似文献
992.
The complexes [Cu(PCHO)2(NCMe)][BF4] (1) and [Cu(PCHO)3][BF4] (2) have been prepared by treating [Cu(NCMe)4][BF4] with two and three equivalents of Ph2P(o-C6H4)C(O)H (abbreviated as PCHO) at room temperature, respectively. The reaction of 1 and (Ph2PC5H4)2Fe (abbreviated as DPPF) affords [Cu(PCHO)(DPPF)][BF4] (3). The molecular structures of 1-3 have been determined by an X-ray diffraction study. The aldehyde groups in 1 are pendant, while one of the formyl groups in 2 is weakly coordinated to the copper ion through the oxygen atom. On the other hand, the copper atom in 3 is strongly chelated by both DPPF and PCHO ligands. 相似文献
993.
Kim MS Yi MJ Lee KH Wagner J Munger C Kim YG Whiteway M Cygler M Oh BH Sacher M 《Traffic (Copenhagen, Denmark)》2005,6(12):1183-1195
Transport protein particle (TRAPP) comprises a family of two highly related multiprotein complexes, with seven common subunits, that serve to target different classes of transport vesicles to their appropriate compartments. Defining the architecture of the complexes will advance our understanding of the functional differences between these highly related molecular machines. Genetic analyses in yeast suggested a specific interaction between the TRAPP subunits Bet3p and Trs33p. A mammalian bet3-trs33 complex was crystallized, and the structure was solved to 2.2 angstroms resolution. Intriguingly, the overall fold of the bet3 and trs33 monomers was similar, although the proteins had little overall sequence identity. In vitro experiments using yeast TRAPP subunits indicated that Bet3p binding to Trs33p facilitates the interaction between Bet3p and another TRAPP subunit, Bet5p. Mutational analysis suggests that yeast Trs33p facilitates other Bet3p protein-protein interactions. Furthermore, we show that Trs33p can increase the Golgi-localized pool of a mutated Bet3 protein normally found in the cytosol. We propose that one of the roles of Trs33p is to facilitate the incorporation of the Bet3p subunit into assembling TRAPP complexes. 相似文献
994.
JIL-1 kinase, a member of the male-specific lethal (MSL) complex, is necessary for proper dosage compensation of eye pigmentation in Drosophila 总被引:2,自引:0,他引:2
Lerach S Zhang W Deng H Bao X Girton J Johansen J Johansen KM 《Genesis (New York, N.Y. : 2000)》2005,43(4):213-215
The upregulation of the JIL-1 kinase on the male X chromosome and its association with the male-specific lethal (MSL) complex suggest that JIL-1 may play a role in regulating dosage compensation. To directly test this hypothesis we measured eye pigment levels of mutants in the X-linked white gene in an allelic series of JIL-1 hypomorphic mutants. We show that dosage compensation of w(a) alleles that normally do exhibit dosage compensation was severely impaired in the JIL-1 mutant backgrounds. As a control we also examined a hypomorphic white allele w(e) that fails to dosage compensate in males due to a pogo element insertion. In this case the relative pigment level measured in males as compared to females remained approximately the same even in the most severe JIL-1 hypomorphic background. These results indicate that proper dosage compensation of eye pigment levels in males controlled by X-linked white alleles requires normal JIL-1 function. 相似文献
995.
Heiss K Junkes C Guerreiro N Swamy M Camacho-Carvajal MM Schamel WW Haidl ID Wild D Weltzien HU Thierse HJ 《Proteomics》2005,5(14):3614-3622
Metal-protein interactions are vitally important in all living organisms. Metalloproteins, including structural proteins and metabolic enzymes, participate in energy transfer and redox reactions or act as metallochaperones in metal trafficking. Among metal-associated diseases, T cell mediated allergy to nickel (Ni) represents the most common form of human contact hypersensitivity. With the aim to elucidate disease-underlying mechanisms such as Ni-specific T cell activation, we initiated a proteomic approach to identify Ni-interacting proteins in human B cells. As antigen presenting cells, B cells are capable of presenting MHC-associated Ni-epitopes to T cells, a prerequisite for hapten-specific T cell activation. Using metal-affinity enrichment, 2-DE and MS, 22 Ni-interacting proteins were identified. In addition to known Ni-binding molecules such as tubulin, actin or cullin-2, we unexpectedly discovered that at least nine of these 22 proteins belong to stress-inducible heat shock proteins or chaperonins. Enrichment was particularly effective for the hetero-oligomeric TRiC/CCT complex, which is involved in MHC class I processing. Blue Native/SDS electrophoresis analysis revealed that Ni-NTA-beads specifically retained the complete protein machinery, including the associated chaperonin substrate tubulin. The apparent Ni-affinity of heat shock proteins suggests a new function of these molecules in human Ni allergy, by linking innate and adaptive immune responses. 相似文献
996.
997.
998.
CR1R2OH, Ri = CH3 or H, react with the complex [CoIII(NH3)5CN]2+ to form an observable intermediate probably via bonding to the nitrogen of the cyanide. This intermediate isomerizes to form a second intermediate. The second intermediate decomposes into Co2+(aq), 5NH4+, CN− and R1R2CO. The plausible structures of the intermediates are discussed. The radicals CH3, CH2CHO, , and are considerably less reactive towards this complex, the formation of intermediates in their presence is not observed. 相似文献
999.
Four new zinc(II) cyclams of the composition {Zn(L)(tp2−) · H2O}n (1), {Zn(L)(H2bta2−) · 2H2O}n (2), [Zn2(L)2(ox2−)] 2ClO4 · 2DMF (3), and Zn(L)(H2btc−)2 · 2DMF (4), where L = cyclam, tp2− = 1,4-benzenedicarboxylate ion, H2bta2− = 1,2,4,5-benzenetetracarboxylate ion, ox2− = oxalate ion, DMF = N,N-dimethylformamide, and H2btc− = 1,3,5-benzenetricarboxylate ion, have been synthesized and structurally characterized by a combination of analytical, spectroscopic and crystallographic methods. The carboxylato ligands in the complexes 1-4 show strong coordination tendencies toward zinc(II) cyclams with hydrogen bonding interactions between the pre-organized N-H groups of the macrocycle and oxygen atoms of the carboxylato ligands. The macrocycles in 1, 2, and 4 adopt trans-III configurations with the appropriate R,R,S,S arrangement of the four chiral nitrogen centers, respectively. However, the complex 3 shows an unusual cis V conformation with the R,R,R,R nitrogen configuration. The finding of strong interactions between the carboxylato ligands and the zinc(II) ions may provide additional knowledge for the improved design of receptor-targeted zinc(II) cyclams in anti-HIV agents. 相似文献
1000.
Miguel A. Novak Marcus V. de Rangel e Silva Maria G.F. Vaz Solange M.S.V. Wardell 《Inorganica chimica acta》2005,358(4):941-946
The pale blue title compound, 4, was obtained from the reaction between 1,7,11,17-tetraaza-2,6,12,16-tetraoxacycloeicosane, Ni(acac)2 and NaBPh4 in aqueous acetone. X-ray structure determination at 120 K revealed that the dication of the ionic complex, 4, contains two independent octahedral NiII centres with trans-Ni2N2O4 chromophores. The macrocyclic ligand and an aqua ligand act as bridges to the two nickel centres: the Ni-O(aquo)-N bond angle is 137.65(17)°. Each Ni centre is bonded to two nitrogens of the macrocycle, to a chelating acac unit, to an ethanol molecule as well as the bridging oxygen of the aqua group. The two nickel atoms sit outside the macrocycle cavity, such that the macrocyclic ligand acts as a canopy for the remainder of the dication. While none of the macrocycle oxygens are involved in the coordination to Ni, they are involved in internal hydrogen bonding with the aqua and ethanol ligands. Magnetic measurements show a paramagnetic behaviour down to 2 K, with an effective moment of 2.8 Bohr magnetons at room temperature. 相似文献