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71.
Dr. Y. L. Tsay 《Heat and Mass Transfer》1995,30(6):473-480
A numerical analysis has been carried out to study the heat removal process from hot channel plate through liquid film evaporation into a countercurrent air flow. The influences of the wall heat flux, the inlet Reynolds number of liquid film and the inlet Reynolds number of moist air on the transfer characteristics are investigated detailedly. The Results show that the interface latent heat transfer associated with the film vaporization causes a temperature drop of the heated plate in the entry region of air flow, which is more significant for a system with higherq
w
, lowerRe
l,in
or largerRe
c, in
. The overall temperature rise of the heated wall is rather small, as compared with the case without interface latent heat transfer. In addition, the difference in results obtained by the one-dimensional and two-dimensional methods is substantial.Die numerische Untersuchung bezieht sich auf den Wärmetransportprozeß von heißen, plattenförmigen Kanalwänden durch Flüssigfilmverdampfung in gegenströmende Luft. Die Einflüsse des Wärmeflusses, der Reynolds-Zahlen, des Flüssigkeitfilms und der Feuchtluft (jeweils am Eintritt) auf das Wärmeübertragungsverhalten werden eingehend untersucht. Die Ergebnisse zeigen, daß die bei der Filmverdampfung eingespeicherte latente Wärme eine Temperaturabnahme der Heizplatte am Eintritt der Luft bewirkt, die mit den Wärmefluß und steigender Reynolds-Zahl für Feuchtluft zunimmt. Die gesamte Temperaturerhöhung der beheizten Wand ist sehr gering im Vergleich mit dem Fall ohne Latentwärmeaustausch. Darüber hinaus resultieren erhebliche Unterschiede in den Ergebnissen, je nachdem, ob eindimensionale oder zweidimensionale Methoden angewandt werden.The financial support of this study by the engineering division of the National Science Council, Taiwan, R.O.C., through the contract NSC 82-0401-E-150-049 is greatly appreciated. 相似文献
72.
73.
Leazer JL Cvetovich R Tsay FR Dolling U Vickery T Bachert D 《The Journal of organic chemistry》2003,68(9):3695-3698
An improved and efficient bromination of 3,5-bis(trifluoromethyl)benzene was developed. A safe and reliable preparation of the potentially explosive 3,5-bis(trifluoromethyl)phenyl Grignard and 3-trifluoromethylphenyl Grignard reagents, from the precursor bromides, is described. Reaction System Screening Tool (RSST) and Differential Thermal Analysis (DTA) studies suggest these trifluoromethylphenyl Grignard reagents can detonate on loss of solvent contact or upon moderate heating. When prepared and handled according to the methods described herein, these Grignard reagents can be safely prepared and carried on to advanced intermediates. 相似文献
74.
The orientation behavior of two series of segmented polyether polyurethanes containing different hard segment length distributions has been studied as a function of the average hard segment length which was varied from one to five methylene bis (p-phenyl isocyanate) (MDI) units. The orientation behavior of the soft segments, isolated hard segments, and of hard segments aggregated in hard domains was determined from the dichroic behavior of representative infrared bands. As the hard segment length increases, a transition in orientation behavior is observed which corresponds to a change in sample morphology.The effects of annealing and hard segment length distribution were also studied and were shown to affect the orientation response through their influence on sample morphology. Orientation hysteresis studies were performed to probe the mechanism of the transverse orientation and orientation inversion which occurred in polyurethanes with the longer, more crystallizable hard segment lengths. 相似文献
75.
R. Schwesinger K. Piontek W. Littke O. Schweikert H. Prinzbach C. Krüger Y.-H. Tsay 《Tetrahedron letters》1982,23(24):2427-2430
According to X-ray crystal structure analyses “cis-benzenetrisimine” () and “cis-benzenetrioxide” () act as tridentate ligands in their 2:1- and 4:1-complexes (Co(C6H9N3)2(NO3)3) and (Ba(C6H6O3)4(ClO4)2), resp. The latter is the rare example of an organic complex with the (approximate) T-symmetry. 相似文献
76.
Jia-Huey Gong Chyuan-Wu Tsay Wen-Cheng Tu Yun Chi Shie-Ming Peng Gene-Hsiang Lee 《Journal of Cluster Science》1995,6(2):289-309
Condensation of be triosmium acetonitrile complex Os3(CO)10(NCMe)2 with the sulfido complex CpW(CO)3(CH2SMe) in refluxing THF solution produced three sulfur-containing compounds Os3(C0)10)(µ-H)(µ-SMe) (1), Os3(CO)11 [S(Me)CH2W(CO)3Cp] (2) and CpWOs3(CO)12(µ-CH2)(µ-SMe) (3). Clusters 2 and 3 were products involving a 1:1 combination of starting materials and were characterized by X-ray diffraction studies. Crystals of 2 belongs to monoclinic space group P 21
/c witha=8.418(2),b = 11.912(2),c = 28.288 Å,=97.64(2)°,Z=4;R
F=0.044,R
W,=0.044. Crystal dara far 3: space group P 21/e,a 18.156(4).b=9.255(6),c = 15.347(4) Å. = 103.49(2)°,Z = 4;R
F
-=0.047,R
W
= 0.045. Upon thermolysis in toluene, the methylene cluster 3 released CO and induced C-H bond activation to afford two tetrametallic carbido clusters with formula CPWOS3(CO)9(µ4-C)(µ-H)2(µ-SMe) (4) and CPWOs3(CO)11(µ4-C)(µ-SMe) (5) as the principle products. The first complex possesses a butterfly framework encapsulating a µ4-C ligmd and a µ-SMe ligand linking a W-Os edge, whereas the second product adopts a puckered, cyclic arrangement of WOs3 metal atoms with µ-SMe ligand located on a nonbonding Os-Os vector. Complex4 crystallizes in monoclinic space group P 21
/c witha=15.633(4) Å,b = 8.699 (3) Å,c=15.422(4) Å,=93.12(2)=°, Z=4,R=0.036,R
W
=0.034 for 2780 observed reflections. Crystal data for5: space groupP nma,a=14.542(3),b=13.710(6),c=11.758(3) Å.Z=4,R
F
=0.038,R
W
= 0.037 for 1826 observed reflections. A variable temperature1H NMR study was also presented to demonstrate the solution fluxionality of5. 相似文献
77.
New light on quantum dot cytotoxicity 总被引:6,自引:0,他引:6
As quantum dots are beginning to be used for in vivo imaging, the question of their long-term effect on cell viability is becoming critical. In this issue of Chemistry & Biology, Lovri? and colleagues examine the likely role of reactive oxygen species in quantum dot cytotoxicity . 相似文献
78.
Two series of oxime esters containing the 2,6-diazaanthracene-9,10-dione bis-(O-benzoyloxime) and 4,5-diazafluoren-9-one O-9-benzoyloxime moieties have been synthesized and tested as photo-induced DNA cleaving agents. All these compounds were found to cleave DNA upon irradiation with 312 nm UV light. The structure-activity relationship of these molecules for DNA cleavage was established. A plausible reaction mechanism is also proposed. 相似文献
79.
80.
A facile synthesis of 3-substituted methyl 4,6-dihydrothieno[3,4-b]thiophene-carboxylate 5,5-dioxides 1 from 3-(phenylthio)-4-acyl-3-sulfolenes 2 and their use as stable precursors of o-dimethylene thiophene 3 in [4 + 2] cycloaddition are described. 相似文献