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Abachi S Abbott B Abolins M Acharya BS Adam I Adams DL Adams M Ahn S Aihara H Alitti J Álvarez G Alves GA Amidi E Amos N Anderson EW Aronson SH Astur R Avery RE Baarmand MM Baden A Balamurali V Balderston J Baldin B Banerjee S Bantly J Bartlett JF Bazizi K Bendich J Beri SB Bertram I Bezzubov VA Bhat PC Bhatnagar V Bhattacharjee M Bischoff A Biswas N Blazey G Blessing S Bloom P Boehnlein A Bojko NI Borcherding F Borders J Boswell C Brandt A Brock R Bross A Buchholz D Burtovoi VS Butler JM 《Physical review letters》1996,77(4):595-600
3.
Abachi S Abbott B Abolins M Acharya BS Adam I Adams DL Adams M Ahn S Aihara H Alitti J Álvarez G Alves GA Amidi E Amos N Anderson EW Aronson SH Astur R Avery RE Baarmand MM Baden A Balamurali V Balderston J Baldin B Banerjee S Bantly J Bartlett JF Bazizi K Bendich J Beri SB Bertram I Bezzubov VA Bhat PC Bhatnagar V Bhattacharjee M Bischoff A Biswas N Blazey G Blessing S Bloom P Boehnlein A Bojko NI Borcherding F Borders J Boswell C Brandt A Brock R Bross A Buchholz D Burtovoi VS Butler JM 《Physical review letters》1996,77(25):5011-5015
4.
Abachi S Abbott B Abolins M Acharya BS Adam I Adams DL Adams M Ahn S Aihara H Alitti J Álvarez G Alves GA Amidi E Amos N Anderson EW Aronson SH Astur R Avery RE Baden A Balamurali V Balderston J Baldin B Bantly J Bartlett JF Bazizi K Bendich J Beri SB Bertram I Bezzubov VA Bhat PC Bhatnagar V Bhattacharjee M Bischoff A Biswas N Blazey G Blessing S Bloom P Boehnlein A Bojko NI Borcherding F Borders J Boswell C Brandt A Brock R Bross A Buchholz D Burtovoi VS Butler JM Carvalho W Casey D 《Physical review letters》1996,76(18):3271-3276
5.
For a great number of processes of technical importance (separation precipitating, adsorption and chemical conversion) an indication of progress of reaction without any temporal delay and gap is required with regard to process optimation. Beside and in addition to thermal analyses and optical methods electrical methods can be used, which depend on measuring of those electric properties, which are connected with each change of phases of the material under test. By use of potentials of medium or high frequency the cell of reaction is free of test probes. This is especially favourable for investigations of such mixtures of phases, in which the surfaces of electrodes would be changed irreversible by sedimentation or separation of phase. In this way the following reactions were studied: precipitation processes in supersaturated aqueous solutions, solution of crystals of potassium chloride, adsorption of alkali solution by ground quartz, sedimentation of mineral substances, separation processes of the system phenol-water and transformation of high polymers. 相似文献
6.
Summary This paper describes a method for theg synthesis of flavone acetates in a sealed capillary tube. The reaction products are separated and purified on a thin-layer plate. The esters are then hydrolyzed on the plate and the parent flavones regenerated. A simple heating device is used which allows for observation of the reaction.
For part IV of this series see Mikrochim. Acta [Wien]1969, 352. 相似文献
Zusammenfassung Beschreibung der Mikrogrammsynthese von Flavonacetaten in einem verschmolzenen Kapillarröhrchen. Die Reaktionsprodukte werden auf einer Dünnschichtplatte getrennt und gereinigt. Dann verseift man die Ester auf der Platte und stellt die freien Flavone dar. Ein einfaches Heizgerät ermöglicht die Beobachtung der Reaktion.
For part IV of this series see Mikrochim. Acta [Wien]1969, 352. 相似文献
7.
End-labeled free-solution electrophoresis of DNA 总被引:1,自引:0,他引:1
Meagher RJ Won JI McCormick LC Nedelcu S Bertrand MM Bertram JL Drouin G Barron AE Slater GW 《Electrophoresis》2005,26(2):331-350
DNA is a free-draining polymer. This subtle but "unfortunate" property of highly charged polyelectrolytes makes it impossible to separate nucleic acids by free-flow electrophoresis. This is why one must typically use a sieving matrix, such as a gel or an entangled polymer solution, in order to obtain some electrophoretic size separation. An alternative approach consists of breaking the charge to friction balance of free-draining DNA molecules. This can be achieved by labeling the DNA with a large, uncharged molecule (essentially a hydrodynamic parachute, which we also call a drag-tag) prior to electrophoresis; the resulting methodology is called end-labeled free-solution electrophoresis (ELFSE). In this article, we review the development of ELFSE over the last decade. In particular, we examine the theoretical concepts used to predict the ultimate performance of ELFSE for single-stranded (ssDNA) sequencing, the experimental results showing that ELFSE can indeed overcome the free-draining issue raised above, and the technological advances that are needed to speed the development of competitive ELFSE-based sequencing and separation technologies. Finally, we also review the reverse process, called free-solution conjugate electrophoresis (FSCE), wherein uncharged polymers of different sizes can be analyzed using a short DNA molecule as an electrophoretic engine. 相似文献
8.
Summary This paper describes techniques for separation and purification of steroids on the thin-layer plate. Two or more operations can be performed on the same plate in order to avoid loss of material and product.When a steroid diketone (progesterone) is treated with 2,4-dinitrophenylhydrazine on silica gel, three products are obtainable. These compounds can be readily purified on the same thin-layer plate and converted to the parent steroid by means of stannous chloride in dilute hydrochloric acid.
Zusammenfassung Trennung und Reinigung von Steroiden auf der Dünnschichtplatte werden beschrieben. Zwei oder mehr Operationen lassen sich, um Substanzverluste zu vermeiden, auf derselben Platte ausführen.Wird ein Diketosteroid (Progesteron) mit 2,4-Dinitrophenylhydrazin auf Kieselgel behandelt, so erhält man drei Reaktionsprodukte, die auf derselben Platte leicht gereinigt und mit Zinn(II)-chlorid in verd. Salzsäure in das entsprechende Ausgangssteroid zurückverwandelt werden können.相似文献
9.
R. Bertram 《Fresenius' Journal of Analytical Chemistry》1966,222(2):189-200
Zusammenfassung Es wird über Aufbau und Leistungsfähigkeit eines neuen oscillometrischen Meßverfahrens zur Verfolgung von Reaktionsabläufen berichtet. Dabei befindet sich die mit dem Reaktionsgut gefüllte Meßzelle in einer speziellen Schaltstrecke, die so mit dem übrigen Schaltkreis gekoppelt ist, daß die sich einstellende Frequenz ein eindeutiges Maß für die in der Zelle ablaufenden Änderungen darstellt. Diese im Bereich zwischen 50 Hz und 1 MHz auftretenden Frequenzen werden mit Hilfe eines angepaßten Überlagerungsverfahrens mit hoher Empfindlichkeit zur Anzeige gebracht. Ein nachgeschalteter Schnellschreiber sorgt für eine momentane, lückenlose Registrierung. Das Verfahren ist im gesamten ionalen Leitfähigkeitsbereich sowohl für Zellen mit als auch ohne direkten Elektrodenkontakt verwendbar. Die Leistungsfähigkeit wird durch registrierte Meßkurven belegt. Unter anderem wurden schnellablaufende Verseifungsreaktionen von Trifluoressigsäurephenylester sowie langdauernde Adsorptionsvorgänge von Natronlauge an Quarzpulver untersucht. Schließlich wurde das Verfahren zur Aufzeichnung bislang unbekannter Auflösungsreaktionen von geschmolzenem Blei in einer Cadmiumchloridschmelze benutzt. Trotz der verzögerungsfreien Anzeige wird eine bisher von keiner Leitfähigkeitsmeßmethode erreichte Relativgenauigkeit von 10–3% gewährleistet.
Besonderer Dank gebührt der Deutschen Forschungsgemeinschaft und dem Fonds der Chemischen Industrie, die diese Arbeit durch Forschungsbeihilfen unterstützt haben. 相似文献
Summary In the field of oscillometry chemical reactions are recorded by means of measuring the electrical properties of the reaction medium. Thus, mainly changes in conductivity and dielectric constant are determined. In case of the method discussed the measuring cell filled with the reaction medium is placed in a special circuit, which is coupled with the main circuit in that way that the resulting frequency represents an unambiguous measure for the changes occurring in the cell. These frequencies in the range between 50 and 106 c/s are recorded with high sensitivity by means of an adapted heterodyne frequency method. The method is applicable in the whole ionic conductivity range for cells with and without direct electrode contact. The efficiency of the method is proved by measuring curves. For example, fast saponification reactions as well as long lasting adsorption reactions of NaOH on quartz powder were recorded. Also the method was applied to investigate the dissolution reactions of molten lead in molten cadmium chloride, that are not yet known. Although the reactions are recorded without delay, a relative accuracy of 10–3% is granted. This accuracy is not reached by any other conductivity method for the time being.
Besonderer Dank gebührt der Deutschen Forschungsgemeinschaft und dem Fonds der Chemischen Industrie, die diese Arbeit durch Forschungsbeihilfen unterstützt haben. 相似文献
10.
Bead cellulose derivatives as supports for immobilization and chromatographic purification of proteins 总被引:3,自引:0,他引:3
H F Boeden K Pommerening M Becker C Rupprich M Holtzhauer F Loth R Müller D Bertram 《Journal of chromatography. A》1991,552(1-2):389-414
Characteristic data are presented for Divicell, a macroporous bead cellulose with excellent flow parameters. The preparation of Divicell derivatives and their properties are described with respect to their application as chromatographic supports. The ion exchangers Divicell DEAE and Divicell CM were manufactured in two types with different exclusion limits and an available capacity for proteins of up to 100 mg/ml gel. Divicell Blue is a bead cellulose with covalently bound Cibacron Blue F3G-A and was found to be a very suitable adsorbent for the selective separation and purification of human serum albumin. Activation of Divicell with sodium periodate, epichlorohydrin and 5-norbornene-2,3-dicarboximido carbonochloridate provided activated supports used for immobilization of ligands in organic solvents and in aqueous solutions. Coupling of amines, diamines, amino acids, carbohydrates and proteins is described. The immobilized ligands retained their biological activity as determined by their specific adsorption of proteins. Divicell alkyl derivatives were tested in hydrophobic interaction chromatography with bovine serum albumin as a model. Examples are presented of the application of Divicell derivatives to the purification of biomacromolecules such as immunoglobulins and lectins by affinity chromatography. The results were comparable to those obtained using the corresponding Sepharose-derived absorbents. 相似文献