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921.
Burckbuchler V Wintgens V Lecomte S Percot A Leborgne C Danos O Kichler A Amiel C 《Biopolymers》2006,81(5):360-370
The ability of DNA to bind polycation yielding polyplexes is widely used in nonviral gene delivery. The aim of the present study was to evaluate the DNA compaction with a new DNA vector using Raman spectroscopy. The polyplexes result from an association of a beta-cyclodextrin polymer (polybeta-CD), an amphiphilic cationic connector (DC-Chol or adamantane derivative Ada2), and DNA. The charge of the polymeric vector is effectively controlled by simple addition of cationic connector in the medium. We used surface enhanced Raman spectroscopy (SERS) to characterize this ternary complex, monitoring the accessibility of adenyl residues to silver colloids. The first experiments were performed using model systems based on polyA (polyadenosine monophosphate) well characterized by SERS. This model was then extended to plasmid DNA to study polybeta-CD/Ada2/DNA and polybeta-CD/DC-Chol/DNA polyplexes. The SERS spectra show a decrease of signal intensity when the vector/DNA charge ratio (Z+/-) increases. At the highest ratio (Z+/- = 10) the signal is 6-fold and 3-fold less intense than the DNA reference signal for Ada2 and DC-Chol polyplexes, respectively. Thus adenyl residues have a reduced accessibility as DNA is bound to the vector. Moreover, the SERS intensity variations are in agreement with gel electrophoresis and zeta potential experiments on the same systems. The overall study clearly demonstrates that the cationic charges neutralizing the negative charges of DNA result in the formation of stable polyplexes. In vitro transfection efficiency of those DNA vectors are also presented and compared to the classical DC-Chol lipoplexes (DC-Chol/DNA). The results show an increase of the transfection efficiency 2-fold higher with our vector based on polybeta-CD. 相似文献
922.
Nikos Lekkas Achilleas Garoufis Joseph Kobe Edward R.T. Tiekink 《Inorganica chimica acta》2006,359(13):4297-4303
The Pd(II) and Pt(II) complexes with triazolopyrimidine C-nucleosides L1 (5,7-dimethyl-3-(2′,3′,5′-tri-O-benzoyl-β-d-ribofuranosyl-s-triazolo)[4,3-a]pyrimidine), L2 (5,7-dimethyl-3-β-d-ribofuranosyl-s-triazolo[4,3-a]pyrimidine) and L3 (5,7-dimethyl[1,5-a]-s-triazolopyrimidine), [Pd(en)(L1)](NO3)2, [Pd(bpy)(L1)](NO3)2, cis-Pd(L3)2Cl2, [Pd2(L3)2Cl4] · H2O, cis-Pd(L2)2Cl2 and [Pt3(L1)2Cl6] were synthesized and characterized by elemental analysis and NMR spectroscopy. The structure of the [Pd2(L3)2Cl4] · H2O complex was established by X-ray crystallography. The two L3 ligands are found in a head to tail orientation, with a Pd?Pd distance of 3.1254(17) Å. L1 coordinates to Pd(II) through N8 and N1 forming polymeric structures. L2 coordinates to Pd(II) through N8 in acidic solutions (0.1 M HCl) forming complexes of cis-geometry. The Pd(II) coordination to L2 does not affect the sugar conformation probably due to the high stability of the C-C glycoside bond. 相似文献
923.
The dinuclear arene ruthenium complexes [RuCl2{C6H5(CH2)3OCO-p-C6H4-OC8H17}]2 (1) and [RuCl2{p-C6H4(CH2COOCH2CH3)2}]2 (2) have been obtained by dehydrogenation of the corresponding cyclohexadiene derivative with ruthenium chloride hydrate. The single-crystal X-ray structure analysis of 2 shows the arene ligands to be involved in slipped-parallel π-π stacking interactions with neighbouring molecules, thus forming infinite chains along the b-axis. The dinuclear complexes 1 and 2 react with two equivalents of triphenylphosphine (PPh3) to give in excellent yield the corresponding mononuclear phosphine complexes [RuCl2{C6H5(CH2)3OCO-p-C6H4-OC8H17}(PPh3)] (3) and [RuCl2{p-C6H4(CH2COOCH2CH3)2}(PPh3)] (4), respectively. The single-crystal X-ray structure analysis of 4 reveals the formation of a dimer through two C-H?Cl interactions in the solid state. 相似文献
924.
Rodolphe F.R. Jazzar Andrew D. Burrows Stuart A. Macgregor Mary F. Mahon 《Inorganica chimica acta》2006,359(3):815-820
Two isomers of the N,O-coordinated acetylpyrrolyl complex [Ru(PPh3)2(CO)(NC4H3C(O)CH3)H] {cis-N,H (1) and trans-N,H (2)} have been prepared as models for catalytic intermediates in the Murai reaction. Complex 2 isomerises to 1 upon heating via a dissociative pathway (ΔH‡ = 195 ± 41 kJ mol−1; ΔS‡ = 232 ± 62 J mol−1 K−1); the mechanism of this process has been modeled using density functional calculations. Complex 2 displays moderate catalytic activity for the Murai coupling of 2′-methylacetophenone with trimethylvinylsilane, but 1 proved to be catalytically inactive under the same conditions. 相似文献
925.
Renata Galvão de Lima Daniella Bonaventura Lusiane Maria Bendhack 《Inorganica chimica acta》2006,359(8):2543-2549
The photochemical and pharmacological studies of the novel [Ru(L)(tpy)NO]3+ L = bpy (2,2′-bipyridine), NH · NHq (quinonediimine) and NH2.NH2cat (o-phenylenediamine) were investigated in aqueous medium. The synthesized nitrosyl ruthenium complexes showed nitric oxide (NO) release under light irradiation at 355 nm for [Ru(L)(tpy)NO]3+ complex with quantum yield of 0.14 ± 0.02, 0.47 ± 0.03 and 0.46 ± 0.02 mol Einstein−1 for L = bpy, NH · NHq and NH2 · NH2cat, respectively, and 0.0065 ± 0.001 mol Einstein−1 for light irradiation at 532 nm for [Ru(NH · NHq)(tpy)NO]3+ complex. The photochemical pathway at 355 nm light irradiation was described as a multi-step mechanism, although at 532 nm it was better attributed to a photo-induced electron transfer. The vasorelaxation induced by NO release produced by light irradiation in visible region from physiological solution of [Ru(NH · NHq)(tpy)NO]3+ complex was evaluated and compared with sodium nitroprusside (SNP). The results showed very similar vasodilator power between both species. 相似文献
926.
Mousa Z. Al-Noaimi Salim F. Haddad Robert J. Crutchley 《Inorganica chimica acta》2006,359(8):2395-2399
The novel azoimine ligand α-acetyl-α-phenylazo-4-chlorophenylazomethine (L) was prepared and characterized. Its coordination chemistry to Ru(II) was investigated by the preparation and characterization of the complex trans-[Ru(bpy)LCl2] where bpy is 2,2′-bipyridine. A crystal structure of this complex showed that L is a bidentate ligand and coordinates to Ru(II) by azo-and imine-nitrogen donor atoms. Cyclic voltammetry and spectroelectrochemistry were performed on this complex and the visible region absorption bands assigned. L is shown to be a strong π-acid ligand. 相似文献
927.
Naokazu Yoshikawa Shinichi Yamabe Yasushi Kai Keiichi Tsukahara 《Inorganica chimica acta》2006,359(14):4585-4593
A series of mononuclear acetonitrile complexes of the type [Ru(CH3CN)(L)(terpy)]2+ {L = phen (1), dpbpy (3), and bpm (5)}, and their reference complexes [RuCl(L)(terpy)]+ {L = phen (2), dpbpy (4), and dpphen (6)} were prepared and characterized by electrospray ionization mass spectrometry, UV-vis spectroscopy, and cyclic voltammograms (CV). Abbreviations of the ligands (Ls) are phen = 1,10-phenanthroline, dpbpy = 4,4′-diphenyl-2,2′-bipyridine, bpm = 2,2′-bipyrimidine, dpphen = 4,7-diphenyl-1,10-phenanthroline, bpy = 2,2′-bipyridine, and terpy = 2,2′:6′,2″-terpyridine. The X-ray structures of the two complexes 2 and 3 were newly obtained. The metal-to-ligand charge transfer (MLCT) bands in the visible region for 1, 3, and 5 in acetonitrile were blue shifted relative to those of the reference complexes [RuCl(L)(terpy)]+. CV for all the [Ru(CH3CN)(L)(terpy)]2+ complexes showed the first oxidation wave at around 0.95 V, being more positive than those of [RuCl(L)(terpy)]+. The time-dependent-density-functional-theory approach (TDDFT) was used to interpret the absorption spectra of 1 and 2. Good agreement between computed and experimental absorption spectra was obtained. The DFT approach also revealed the orbital interactions between Ru(phen)(terpy) and CH3CN or Cl−. It is demonstrated that the HOMO-LUMO energy gap of the acetonitrile ligand is larger than that of the Cl− one. 相似文献
928.
Three ternary zinc complexes of the open chain polycarboxylic acid, tricarballylic (1,2,3-propane-tricarboxylic) acid (PTCH3) have been isolated and characterized with crystallographic and physicochemical techniques. [Zn(PTCH)(phen)(H2O)]2 · 4H2O (1) (where phen = 1,10-phenanthroline) has a unique dinuclear structure, while [Zn(PTCH)(bpy)]n · 3nH2O (2) and [Zn(PTCH)(epy)]n · 4nH2O (3) (where bpy = 4,4′-bipyridine and epy = 1,2-bis(4-pyridine)ethane) have 2D polymeric structures. The bis-deprotonated ligand, in all three complexes, uses for coordination only two oxygen atoms, which belong to the same carboxylate in 1, and to two different carboxylates in 2 and 3. 相似文献
929.
Ulrich Jürgen Scheele 《Inorganica chimica acta》2006,359(15):4891-4900
A series of six 3,6-bis(imidazolium-3-yl)pyridazine derivatives with different imidazole-N substituents have been synthesized and isolated as the salts [H2L]Cl2 (1a)-(6a) and [H2L](PF6)2 (1b)-(6b). Solid state structures have been determined crystallographically for eleven out of the twelve compounds, revealing diverse hydrogen bonding patterns that involve the imidazolium-C2H units and the anions. N-heterocyclic carbene (NHC) mercury(II) complexes [Hg2L2](PF6)4 (7)-(9) are readily formed in good yields from ligand precursors [H2L](PF6)2 and Hg(OAc)2, as long as imidazole-N substituents are not too bulky. X-ray crystallography reveals double helical bimetallic arrangements for the stable [Hg2L2]4+ cations. Ligand scrambling in [Hg2L2]4+ occurs only in the presence of free carbene precursor, presumably via an associative mechanism. 相似文献
930.
The reaction of [Ti(cp∗)2(BTMSA)] (1) (cp∗ = η5-C5Me5, BTMSA = bis(trimethylsilyl)acetylene) with malonic acids ((HOOC)2CR2, R = H, Me) and N,N-dimethylglycine resulted in the formation of titanium(IV) dicarboxylato complexes [Ti(cp∗)2{(OOC)2CR2}] (R = H, 2; R = Me, 3) and an α-amino acid titanium(III) complex [Ti(cp∗)2(OOCCH2NMe2)] (4). The identities of complexes 2-4 were confirmed by microanalysis, 1H and 13C NMR spectroscopy (2, 3), ESI-MS and CID experiments (2, 3) as well as by ESR and magnetic measurements (μeff = 1.81, 298 K) for 4. Single X-ray diffraction analyses of 2 and 4 exhibited monomolecular complexes in which the titanium atom is distorted tetrahedrally coordinated by two η5-C5Me5 rings and by the chelating bound malonato-κ2O,O′ (2) and N,N-dimethylglycinato-κ2O,O′ ligand (4). 相似文献