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981.
Jackowski M Szeliga J Kłodzińska E Buszewski B 《Analytical and bioanalytical chemistry》2008,391(6):2153-2160
Microorganisms like bacteria, viruses, fungi, etc. have a major impact on human, animal, and plant life. Several decades ago
it was observed that intact cells suspended in an isotonic salt solution moved toward the anode and the mobility was proportional
to the density of the charge located on the cell surfaces. Since then, efforts have been made to make electrophoresis a useful
tool in cell studies. Microorganisms are no exception. In the present work we applied the capillary zone electrophoresis (CZE)
with dynamical modification of the capillary surface for separation of E. coli and P. vulgaris. The same method was used for identification of E. coli in infected urine (direct injection - UTIs) and also for identification of Helicobacter pylori which is a gram-negative bacillus responsible for one of the most common infections found in humans worldwide. Using spectrophotometric
measurements at λ = 214 nm we proved that it is possible to measure the concentration of bacterial cells up to 5 × 108 cells/mL. Recent studies have demonstrated very practical uses for electrophoretic techniques, especially in the field of
medical diagnosis.
Figure The developed CZE method allows the rapid analysis and identification of pathogenic bacteria: example shown illustrates the
identifcation of E. coli in a urine sample determined much more rapidly than with conventional culturing on Petri dishes
Presented at the 11th International Conference on Chemistry and the Environment, 9–12 September 2007, Torun, Poland. 相似文献
982.
Sébastien G. Guillet Dr. Ishfaq Ibni Hashim Marek Beliš Prof. Dr. Kristof Van Hecke Prof. Dr. Catherine S. J. Cazin Prof. Dr. Steven. P. Nolan 《欧洲无机化学杂志》2023,26(24):e202300327
A simple synthetic method to access a wide range of [Rh(acac)(CO)(NHC)] complexes is described. In situ infra-red monitoring provides insights into the mechanism of the reaction, including the identification of a key intermediate. An understanding of the reaction mechanism leads to the discovery of novel pathways to commonly used congeners. 相似文献
983.
Monika Paszkiewicz Aleksandra Orlita Alicja Dziabas Marek Gołębiowski Ewa Łojkowska Janusz Szafranek Edmund Maliński Piotr Stepnowski 《Chromatographia》2008,67(7-8):653-657
Sequential simplex methods are common and efficient optimization techniques applied in analytical chemistry. This study reports
on the optimization of LC separation of coumarins using a variable-size simplex algorithm. The solvent systems consisted of
methanol, water and tetrahydrofuran. Using an optimized method, seven standard simple coumarins and furanocoumarins derived
from plants were successfully separated in one chromatographic run. The mobile phase at the point corresponding to the optimum
consisted of 34% MeOH, 59% H2O and 7% THF. Applying a solvent mixture in this proportion permitted separation of all critical pairs, such as esculetin/scopoletin,
scopoletin/umbelliferone, umbelliferone/coumarin and xanthotoxin/psoralen. The retention ratio factors k for coumarins at the optimum of the simplex algorithm lay in the range 1 < k < 4. The optimal conditions assigned to the coumarin standards were then applied to the plant matter: herb of the rue (Ruta graveolens L., Rutae herba), anthodium of the camomile (Chamomilla recutita L., Chamomillae anthodium), herb of the southernwood (Artemisia abrotanum L., Abrotani herba), and radix of the lovage (Levisticum officinale K., Levistici radix). The validity of the method was confirmed with respect to these samples. 相似文献
984.
Baird B Pawlikowski AV Su J Wiench JW Pruski M Sadow AD 《Inorganic chemistry》2008,47(22):10208-10210
Optically active C 3-symmetric monoanionic ligands are uncommon in organometallic chemistry. Here we describe the synthesis of readily prepared tris(4 S-isopropyl-2-oxazolinyl)phenylborate [To (P)] and fluxional, zwitterionic four- and five-coordinate iridium(I) compounds [Ir(To (P))(eta (4)-C 8H 12)] ( 4) and [Ir(To (P))(CO) 2] ( 5). The highly fluxional nature of 4 and 5 makes structural assignment difficult, and the interaction between the iridium(I) center and the [To (P)] ligand is established by solid-state and solution (15)N NMR methods that permit the direct comparison between solution and solid-state structures. Although iridium cyclooctadiene 4 is a mixture of four- and five-coordinate species, the dicarbonyl 5 is only the five-coordinate isomer. The addition of electrophiles MeOTf and MeI provides the oxazoline N-methylated product rather than the iridium methyl oxidative addition product. N-Methylation was unequivocally proven by through-bond coupling observed in (1)H- (15)N HMBC experiments. 相似文献
985.
A bitopic ligand 2-hydroxy-1-(tetrazol-1-yl)-3-(tetrazol-2-yl)propane (12pbtzOH) was synthesized and reacted with Fe(ClO4)(2).6H2O, giving a 1D coordination polymer {[Fe(12pbtzOH)2(CH3CN)2](ClO4)(2).2CH3CN} infinity that exhibits a high-spin to low-spin transition (T1/2(downward arrow)=T1/2(upward arrow) congruent with 104 K). This is an unprecedented example of an iron(II) complex containing Fe(tetrazolyl) 4(MeCN)2 cores. 相似文献
986.
This paper reports new application of new transmission X-ray microscopy powered by a synchrotron source for the study of aqueous based clay suspensions. This paper delineates the advantages and limitations of this method. The tested transmission X-ray microscopy (TXM) technique has shown good agreement with the cryo-stage SEM technique. The spacial resolution of this TXM technique is 60 nm and clay particles with diameter below 500 nm are clearly visible and their pseudohexagonal symmetry is recognizable in detail. It is clearly demonstrated the methodology of implementing TXM to study aqueous based clay suspensions that are close to approximately 60 nm tomographic resolution. The technique enables us to study discrete structure of clay suspensions in water and within aggregates. This has never been previously possible. Larger crystals, more compact aggregates and less colloidal fraction present in kaolinite from Georgia has impact on faster settling and gelling in denser suspension than for Birdwood kaolinite in which colloidal particles create gel-like networking in less dense aqueous suspension. 相似文献
987.
A selective method for the synthesis of 1,6-substituted glycolurils has been developed. The glycolurils have been used for the synthesis of methylene-bridged glycoluril dimers bearing hydrogen atoms on their convex face. Depending on the side walls of the dimers, different modes of self-assembly in the solid state have been described using X-ray crystallography. 相似文献
988.
A facile approach to carbapenams via Kinugasa reaction between terminal copper acetylides and nonracemic cyclic nitrones derived from malic and tartaric acid is reported. The stereochemical preferences observed in these reactions are explained. The reaction provides an entry to the carbapenams basic skeleton. 相似文献
989.
Radka Křikavová Ján Vančo Tomáš Šilha Jaromír Marek 《Journal of Coordination Chemistry》2016,69(16):2422-2436
Platinum(II) complexes, [Pt(Lx)X2] (1–6), where X = Br or I and Lx = 2,2′-bipyridine or 1,10-phenanthroline derivatives (5,5′-dimethyl-2,2′-bipyridine (5-Mebpy), 4,4′-dimethyl-2,2′-bipyridine (4-Mebpy), and 5-amino-1,10-phenanthroline (5-NH2phen)) were prepared. The complexes were characterized by the elemental analysis, mass spectrometry, infrared, and multinuclear (1H, 13C and 195Pt) 1-D and 2-D NMR spectroscopies, and by single-crystal X-ray analysis of [Pt(4-Mebpy)I2] (4). All the platinum(II) complexes (1–6) were evaluated for in vitro cytotoxicity against human cancer cell lines A2780 and A2780R, and against non-malignant MRC5 cell line. All the complexes were nontoxic up to the 50 μM concentration, although they were found to readily bind to calf-thymus DNA (CT-DNA), as determined by spectrophotometric titration (Kb ≈ 107 M?1) and ethidium bromide displacement assay. 相似文献
990.
Marek Gołębiowski Aleksandra Ostachowska Monika Paszkiewicz Mieczysława I. Boguś Emilia Włóka Marta Ligęza-Żuber Piotr Stepnowski 《Chemical Papers》2016,70(10):1360-1369
Entomopathogenic fungi are referred to as potential candidates as insect pest control agents. The objective of the study was to identify fatty acids and amino acids from Conidiobolus coronatus cultured on two different media. Each medium was extracted with ethyl acetate and its mixtures with isopropanol, acetonitrile and methanol. Analyses of fatty acids and amino acids of entomopathogenic fungus C. coronatus were performed by means of gas chromatography coupled with mass spectrometry. The analysis showed that the fungus C. coronatus produces the following groups of compounds: fatty acids and amino acids; α- and β-glucopyranose were also identified. The identified fatty acids included 12–20, 22 and 24 carbon atoms per chain. The highest content of fatty acids was detected in a mycelium sample cultured in a liquid minimal medium extracted with ethyl acetate. The lowest content of these organic compounds was identified in mycelium cultured in a liquid nutrient-rich medium extracted with ethyl acetate–methanol mixture. Fatty acids were found to account for 62.0 mass % to 94.4 mass % of all organic compounds in the analyzed mycelia. C18:1 acids were detected in the highest amounts when ethyl acetate was used as the extracting agent. The identified amino acids accounted for 4 mass % to 21 mass % of all organic compounds. Upon extraction of C. coronatus mycelium samples with the ethyl acetate—methanol mixture, two anomeric forms of glucose were also identified. An analysis of the studied material confirmed, that the entomopathogenic fungus C. coronatus is a very rich source of organic compounds, which might encourage its further research so as to identify an even larger number of compounds being produced by this species. 相似文献