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951.
952.
Bidusenko I. A. Cherimichkina N. A. Schmidt E. Yu. Trofimov B. A. 《Russian Journal of Organic Chemistry》2017,53(3):470-471
Russian Journal of Organic Chemistry - Chalcone reacted with acetylene in a suspension of KOH in DMSO at 90°C (30 min) to give 36% of 2-methyl-3,5-diphenylfuran. 相似文献
953.
Investigating Asymptotic Suction Boundary Layers using a One-Dimensional Stochastic Turbulence Model
The one-dimensional turbulence model (ODT) is applied to study turbulent asymptotic suction boundary layers for a Reynolds number of Re = u∞/v0 = 333, where u∞ and v0 are the free stream and suction velocity, respectively. In here we will demonstrate that a large eddy suppression mechanism may reduce the influence of ODT model parameters, such as the viscous cut-off parameter Z. (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
954.
We investigate the Frobenius number, genus, type, and minimal presentation of a class of numerical semigroups of embedding dimension 4 of the form \(S = \langle a_1, a_2, a_3, a_4 \rangle \) such that \(a_1 + a_4 = a_2 + a_3\). The investigation focuses on determining the Apery set of S with respect to the multiplicity. 相似文献
955.
Lars Erik Schmidt Daniel Schmäh Yves Leterrier Jan-Anders E. Månson 《Rheologica Acta》2007,46(5):693-701
The photocuring of three different highly functional acrylates—Di-pentaerythritol penta/hexaacrylate (DPHA) and two hyperbranched
molecules (HBP), one with a stiff polyester and one with a more flexible polyether structure—was investigated by means of
photorheology, photo differential scanning calorimetry, and beam bending. Special attention was paid to the influence of the
composition of DPHA/HBP reactive blends and UV intensity on gelation and vitrification and the resulting dynamics of the internal
stress. It was found that adding HBPs to DPHA did not influence gelation significantly, but shifted the onset of vitrification
to higher conversions and thus caused lower internal stresses in the material. Increasing UV intensity increased both the
conversion at vitrification, thus retarding the build-up of internal stresses, and the ultimate conversion, thus increasing
the final stress level. The obtained conversion, gelation, and vitrification data were assembled into time-intensity transformation
diagrams, thus providing a useful tool for optimizing photocuring.
This paper was presented at Annual European Rheology Conference (AERC) held in Hersonisos, Crete, Greece, April 27–29, 2006. 相似文献
956.
Dr.-Ing. J. Schütt Mogro Professor Dr.-Ing. Th. E. Schmidt 《Heat and Mass Transfer》1976,9(2):129-138
Zusammenfassung Der Wärme- und Stoffübergang bei der Kondensation von Dampf aus einem Gas-Dampf-Gemisch bei sehr hohen Reynolds-Zahlen wurde theoretisch und experimentell untersucht. In einem senkrechten Messingrohr wurde ein Gemisch aus Monofluortrichlormethan (R11) und Stickstoff mit Gaskonzentrationen XG+~0,01...0,42 bei Re +~70000... 450000 gekühlt; die Reynoldszahl der Kondensatfilmstromungerreichte Werte von über 1000. Eine mathematische Methode wurde entwickelt, um verschiedene Größen als Funktion der Hauptparameter Gaskonzentration, Reynoldszahl des Gemisches und Kühllange darzustellen.
Bezeichnungen a, b Koeffizienten - b dimensionslose Schichtdicke - cp spezifische Warmekapazität - d Durchmesser - D Diffusionskoeffizient - F Oberfläche - g Fallbeschleunigung - h spezifische Enthalpie - m Massenstrom - p Druck - q Wärmestromdichte - Q Wärmestrom - r Verdampfungsenthalpie - s Filmdicke - t Temperatur - U allgemeiner Funktionswert - U Umfang - v spezifisches Volumen - w Geschwindigkeit - x Molanteil - y Massenanteil - z Längskoordinate der Rohrströmung - X,Y,Z allgemeine unabhangige Variablen - Wärmeübergangskoeffizient - Stoffübergangskoeffizient - dynamische Viskosität - Wärmeleitkoeffizient - kinematische Viskosität - Dichte - Tautemperatur - Partialdruckanteil - Molmasse Indices a außen - B Bezugszustand - D Dampf - f Phasengrenzfläche - G Gas - gem Gemisch - i innen - k Strömungskern - K Kondensat - Kv konvektiv - L Kolbenstellung - m mittel - W Wand - z örtlich, an der Stelle z - Funktionswert integraler Mittelwert - 0 bei z=0 (Eintritt) 相似文献
The separation of gas-steam-mixtures by condensation in a vertical tube at high reynold-numbers
Heat and mass transfer for condensation from a gas-vapor-mixture with very high Reynolds-numbers was analyzed on a theoretical and experimental basis. A mixture of monofluorotrichloromethane (R 11) and nitrogen was cooled in a vertical brass tube. The gas concentrations and the Reynolds-numbers comprised the ranges XG t+~0.01...0.42 and Re t+~70,000...450, 000; the Reynolds-number of the condensate film flow reached values of above 1000. A mathematical method was developed to show the various values as function of the main parameters, such as gas concentration, Reynolds-number of the mixture and cooling length.
Bezeichnungen a, b Koeffizienten - b dimensionslose Schichtdicke - cp spezifische Warmekapazität - d Durchmesser - D Diffusionskoeffizient - F Oberfläche - g Fallbeschleunigung - h spezifische Enthalpie - m Massenstrom - p Druck - q Wärmestromdichte - Q Wärmestrom - r Verdampfungsenthalpie - s Filmdicke - t Temperatur - U allgemeiner Funktionswert - U Umfang - v spezifisches Volumen - w Geschwindigkeit - x Molanteil - y Massenanteil - z Längskoordinate der Rohrströmung - X,Y,Z allgemeine unabhangige Variablen - Wärmeübergangskoeffizient - Stoffübergangskoeffizient - dynamische Viskosität - Wärmeleitkoeffizient - kinematische Viskosität - Dichte - Tautemperatur - Partialdruckanteil - Molmasse Indices a außen - B Bezugszustand - D Dampf - f Phasengrenzfläche - G Gas - gem Gemisch - i innen - k Strömungskern - K Kondensat - Kv konvektiv - L Kolbenstellung - m mittel - W Wand - z örtlich, an der Stelle z - Funktionswert integraler Mittelwert - 0 bei z=0 (Eintritt) 相似文献
957.
Dr. rer. nat. D. W. Schmidt Ing. W. Schmidt Dipl.-Phys. W. J. Wagner 《Heat and Mass Transfer》1973,6(4):221-227
Measurements of the temperature fluctuations in flows are restricted to low fluctuation frequencies, if the temperature probes which have been available and which have a relative high thermal inertia are used. A newly constructed metalfilm probe, which works in principle as a resistance thermometer, overcomes this restriction to a large degree so that temperature fluctuations in the order of 0.01 °C can be measured up to fluctuation frequencies of about 5 kHz. The construction, the procedure of manufacture, and a method of calibration are presented for the newly developed probe, and its applicability for the measurement of temperature fluctuations in flows is demonstrated by some examples (measurements of the natural temperature fluctuations in the wake of a circular rod in air flow at a Reynolds number of about 5 · 104). Some further applications of the probe are mentioned, in which its high sensitivity and its low thermal inertia is especially advantageous (measurement of flow velocities and measurement of fast temperature variations by infra-red detectors). 相似文献
958.
Although ischemic heart disease tends to cluster in families, previous studies have reported a modest (2-fold increased risk) to strong (10-fold increased risk) contribution of family history to the explanation of disease occurrence. The authors assessed the familial aggregation of early-onset myocardial infarction in 11,307 adults aged <65 years who participated in the Third National Health and Nutrition Examination Survey. Logistic regression was used to obtain odds ratios (ORs) and 95% confidence intervals (CIs). A parental history was more common in those with (n = 237) than in those without (n = 11,070) a myocardial infarction (19.8 vs. 7.9%, p < or = 0.01). Adults with a parental history were also more likely to have multiple risk factors for cardiovascular disease (OR for four or five risk factors compared with none: 2.9, 95% CI: 1.4, 6.3). After multivariate adjustment, the likelihood of myocardial infarction was more than three times greater among adults with a parental history than among those without (95% CI: 1.7, 6.7). A maternal history of myocardial infarction was strongly associated (OR = 6.1, 95% CI: 2.1, 17.4) with an increased likelihood of myocardial infarction, and a paternal history was associated with a 3-fold (95% CI: 1.5, 6.3) increased likelihood of myocardial infarction after adjustment for cardiovascular disease risk factors. These results suggest a familial aggregation of early-onset myocardial infarction and show that family history is strongly associated with cardiovascular disease risk factors. 相似文献
959.
In this paper, we present a smoothing technique which can be understood as a Quasi-Newton method. The idea of this preconditioner is that it approximates the symbol of the inverse Hessian, which has smoothing behavior. This symbol is derived analytically for the Stokes equations and investigated numerically for a flow with a Reynolds number of 80. The resulting symbol is then approximated by differential operators, which will lead to a method similar to Sobolev Smoothing. (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
960.
The synthesis, structural, and thermal characterization of lithium cyanate are reported in this work. LiOCN forms crystals in the trigonal crystal system. The structure was solved in the space group R$\bar{3}$ m. It is isomorphous to the structure of sodium cyanate. In the temperature range from –90 °C up to the melting point no phase transition was observed. Furthermore the vibrational Raman spectrum was measured. The system KOCN‐LiOCN shows a dystecticum and the new phase was confirmed by powder X‐ray diffraction. 相似文献