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981.
A liquid chromatographic tandem mass spectrometric method for the determination of trandolapril in human plasma has been developed and fully validated. The article describes, in detail, the bioanalytical procedure and summarizes the validation results obtained. The samples were extracted using HLB Oasis solid-phase extraction cartridges. The chromatographic separation was performed on X-Terra C8 MS column (150 mm × 4.6 mm i.d., 5 μm particle size) using a mobile phase consisting of acetic acid 20 mM and triethylamine 4.3 mM/acetonitrile (40:60 (v/v)), pumped isocratically at 0.35 ml/min.
The analytes were detected using a micromass quattro micro triple quadrupole mass spectrometer with positive electrospray ionization in multiple reaction-monitoring (MRM) mode. Tandem mass spectrometric detection enabled the quantitation of trandolapril down to 2.0 ng/ml. Calibration graphs were linear (r better than 0.996, n = 9) in the concentration ranges 2.0–750 ng/ml and the intra- and inter-day R.S.D. values were less than 3.83 and 3.86% for trandolapril. 相似文献
982.
Zusammenfassung Es wurden Hexamminmetallkomplexe von Nickel(II), Chrom(III) und Kobalt(III) mit verschiedenen Oxo- und Thio-aniogen der Übergangsmetalle dargestellt und röntgenographisch sowie IR-spektroskopisch untersucht. Von einigen Verbindungen wurden kristallographische Daten ermittelt. An Hand der IR-Spektren wurde der Einfluß der Kationen auf die inneren Schwingungen der Anionen untersucht sowie auch die Abhängigkeit der Schwingungen der Kationen von der Natur der Anionen. Besonders wurden die NH3-rocking-Schwingungen in dieser Hinsicht untersucht, da sie bei gleichem Zentralatom des Amminkomplexes stark von der Art des Anions abhängig und somit für eine bestimmte Verbindung sehr charakteristisch sind.
Mit 1 Abbildung 相似文献
Hexammin metal chalcogenometallates
The preparation, the vibrational spectra, and X-ray data of oxo and thiometallates of transition metal hexammines are reported. The vibrational spectra and especially the influence of the anions on the NH3-rocking vibration are discussed.
Mit 1 Abbildung 相似文献
983.
Amiodarone (AD) therapy for cardiac arrhythmia frequently leads to cutaneous phototoxicity. Amiodarone and its metabolite, desethylamiodarone (DEA), photosensitized hemolysis of red blood cells (RBC) and were phototoxic to lymphocytes. Hemolysis photosensitized by 3.3 μ M AD was partially oxygen dependent and was partially quenched 5 m M sodium azide, 50 m M mannitol, superoxide dismutase (251 U/me e ) and catalase (1500 U/m e ), but was unaffected when H2 O was replaced by D2 O. These results suggest that membrane damage may be important in the in vivo phototoxicity to AD, that both oxygen dependent and oxygen independent mechanisms may operate, and that active oxygen species such as O2 and hydrogen peroxide may be involved. Photohemolysis was more rapid in the presence of DEA than of AD. However, this may be due to the greater fragility of the cell membrane in the presence of DEA. The greater phototoxicity of DEA than AD towards lymphocytes was not due to greater membrane fragility. 相似文献
984.
Jorge Barbosa Maria Luz Ferreira Fernando Ramos Maria Irene Noronha da Silveira 《Accreditation and quality assurance》2007,12(10):543-551
The use of nitrofuran veterinary drugs as antibacterial compounds in food-producing animals has been banned in the EU since
1995. As nitrofurans are extensive and rapidly metabolized, control of their illegal use in animal production must be done
in edible tissues by LC-MS/MS analysis in order to determine persistent tissue-bound metabolites. The introduction during
2002 of the multi-residue detection of nitrofuran tissue-bound metabolites by LC-MS/MS for nitrofuran control in Portuguese
Residues Monitoring Plan, revealed the presence of 5-morpholinomethyl-3-amino-2-oxozolidinone (AMOZ), the bound residue of
furaltadone, in a large number of samples, namely in meat poultry samples. From the 226 analysed samples in the last 4 months
of 2002, 78 were non-compliant due to the presence of AMOZ (61 broilers, 11 turkeys, 5 quails and 1 pig). In this context,
the aim of this paper is to describe the analytical data obtained on meat samples collected from various animal species under
official Portuguese control for nitrofuran drug residues during the so-called “Portuguese nitrofuran crisis”.
Presented at the AOAC Europe Workshop, November 2006, Limassol, Cyprus. 相似文献
985.
By reaction of [NBu(4)](2)[Pt(2)(&mgr;-C(6)F(5))(2)(C(6)F(5))(4)] with 1,8-naphthyridine (napy), [NBu(4)][Pt(C(6)F(5))(3)(napy)] (1) is obtained. This compound reacts with cis-[Pt(C(6)F(5))(2)(THF)(2)] to give the dinuclear derivative [NBu(4)][Pt(2)(&mgr;-napy)(&mgr;-C(6)F(5))(C(6)F(5))(4)] (2). The reaction of several HX species with 2 results in the substitution of the bridging C(6)F(5) by other ligands (X) such as OH (3), Cl (4), Br (5), I (6), and SPh (7), maintaining in all cases the naphthyridine bridging ligand. The structure of 3 was determined by single-crystal X-ray diffraction. The compound crystallizes in the monoclinic system, space group P2(1)/n, with a = 12.022(2) ?, b = 16.677(3) ?, c = 27.154(5) ?, beta = 98.58(3) degrees, V = 5383.2(16) ?(3), and Z = 4. The structure was refined to residuals of R = 0.0488 and R(w) = 0.0547. The complex consists of two square-planar platinum(II) fragments sharing a naphthyridine and OH bridging ligands, which are in cis positions. The short Pt-Pt distance [3.008(1) ?] seems to be a consequence of the bridging ligands. 相似文献
986.
Chen IA Salehi-Ashtiani K Szostak JW 《Journal of the American Chemical Society》2005,127(38):13213-13219
We are engaged in a long-term effort to synthesize chemical systems capable of Darwinian evolution, based on the encapsulation of self-replicating nucleic acids in self-replicating membrane vesicles. Here, we address the issue of the compatibility of these two replicating systems. Fatty acids form vesicles that are able to grow and divide, but vesicles composed solely of fatty acids are incompatible with the folding and activity of most ribozymes, because low concentrations of divalent cations (e.g., Mg(2+)) cause fatty acids to precipitate. Furthermore, vesicles that grow and divide must be permeable to the cations and substrates required for internal metabolism. We used a mixture of myristoleic acid and its glycerol monoester to construct vesicles that were Mg(2+)-tolerant and found that Mg(2+) cations can permeate the membrane and equilibrate within a few minutes. In vesicles encapsulating a hammerhead ribozyme, the addition of external Mg(2+) led to the activation and self-cleavage of the ribozyme molecules. Vesicles composed of these amphiphiles grew spontaneously through osmotically driven competition between vesicles, and further modification of the membrane composition allowed growth following mixed micelle addition. Our results show that membranes made from simple amphiphiles can form vesicles that are stable enough to retain encapsulated RNAs in the presence of divalent cations, yet dynamic enough to grow spontaneously and allow the passage of Mg(2+) and mononucleotides without specific macromolecular transporters. This combination of stability and dynamics is critical for building model protocells in the laboratory and may have been important for early cellular evolution. 相似文献
987.
Giuliana Biagi Fabio Ciambrone Irene Giorgi Oreste Livi Valerio Scartoni Pier Luigi Barili 《Journal of heterocyclic chemistry》2002,39(5):889-893
New tricyclic 1,2,3‐triazolo‐1,2,4‐triazolo‐pyridazine derivatives, bearing a methyl substituent on the 1,2,3‐triazole ring, were prepared as potential biological agents. N‐Methylation of dimethyl 1,2,3‐triazole‐4,5‐dicarboxylate allowed synthesis of the isomeric 1‐methyl‐4,7‐dihydroxy and 2‐methyl‐4,7‐dihydroxy triazolo‐pyridazines 4a and 4b which, by a chlorination reaction, gave the corresponding 1‐methyl‐4‐chloro‐( 6a ), 1‐methyl‐7‐chloro‐ ( 6b ) and 2‐methyl‐4‐chloro‐ ( 9 ) substituted 1,2,3‐triazolo‐pyridazines. The nucle‐ophilic substitution with hydrazine hydrate and the suitable cyclization to form the 1,2,4‐triazole ring, provided the expected tricyclic isomeric derivatives 8a, 8b and 11 respectively. The p‐methoxybenzyl substituent, introduced as a leaving group to obtain either v‐triazolo‐pyridazine or v‐triazolo‐s‐triazolo‐pyri‐dazine derivatives unsubstituted on the 1,2,3‐triazole ring, appeared inadequate. Some compounds underwent binding assays toward the adenosine A1and A2A receptors. 相似文献
988.
The orientational dynamics of a homeotropically aligned nematic liquid crystal, 4'-pentyl-4-biphenylcarbonitrile (5-CB), is studied over more than six decades of time (500 fs to 2 mus) using optical heterodyne detected optical Kerr effect experiments. In contrast to the dynamics of nematogens in the isotropic phase, the data do not decay as a highly temperature-dependent exponential on the longest time scale, but rather, a temperature-independent power law spanning more than two decades of time, the final power law, is observed. On short time scales (approximately 3 ps to approximately 1 ns) another power law, the intermediate power law, is observed that is temperature dependent. The power law exponent of the correlation function associated with the intermediate power law displays a linear dependence on the change in the nematic order parameter with temperature. Between the intermediate power law and the final power law, there is a crossover region that displays an inflection point. The temperature-dependent orientational dynamics in the nematic phase are shown to be very different than those observed in the isotropic phase. 相似文献
989.
Photoproducts in double-stranded DNA induced by 193 nm radiation have been investigated. Double-stranded, supercoiled pBR322 DNA in buffered aqueous solution was exposed to varying fluences of 193 nm radiation from an ArF excimer laser. The quantum yields for formation of cyclobutylpyrimidine dimers, frank strand breaks and alkali labile sites were calculated from the conversion of supercoiled (Form I) DNA to relaxed (Form II) DNA after treatment with Micrococcus luteus dimer-specific endonuclease, no treatment, or treatment with alkali and heat, respectively. The quantum yields were 1.65 (+/- 0.03) X 10(-3) for pyrimidine dimers, 9.4 (+/- 3.2) X 10(-5) for frank strand breaks and 9.6 (+/- 3.6) X 10(-5) for alkali labile sites. The quantum yields for pyrimidine dimers and strand breaks and alkali labile sites were not affected by 10 nM mannitol. The relative quantum yields for these DNA photoproducts induced by 193 nm radiation differed markedly from those produced by 254 nm radiation. 相似文献
990.
Giuliana Biagi Irene Giorgi Oreste Livi Federica Pacchini Valerio Scartoni Oreste Leroy Salerni 《Journal of heterocyclic chemistry》2005,42(5):743-749
Title compounds were obtained starting from the key imidazole intermediate, 5‐amino‐1‐phenyl‐methyl‐2‐mercapto‐1H‐imidazole‐4‐carboxylic acid amide 5 , readily derived from the base catalyzed rearrangement of a thiazole, 5‐amino‐2‐phenylmethylaminothiazole‐4‐carboxylic acid amide 4 . Alkylation of the thiol function on 5 with phenylmethyl and allylic chlorides gave compounds 6 and 7 respectively. Cyclization of 6 with a variety of esters afforded 8‐phenylmethylthiohypoxanthines, 8–11 . Similarly, 7 was cyclized to 8‐allylthiohypoxanthines, 20–21 . Compound 5 was also cyclized, but formed 8‐mercaptohypox‐anthines, 22–24 . Alkylation of 8‐mercaptohypoxanthines afforded 8‐alkylthiohypoxanthines, 8, 9,25 and 26 (see Scheme 2). Chlorination of 9–11 afforded 16–18 ; adenine 19 was derived from 16 . Oxidation of hypox‐anthines 8–11 with m‐chloroperbenzoic acid gave the corresponding 8‐phenylmethylsulfonyl derivatives 12 ‐ 15 . These derivatives proved resistant to nucleophilic displacement reactions with primary amines. 相似文献