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981.
Synthesis and functional properties of strongly luminescent diphenylamino end-capped oligophenylenes
Two novel homologous series of oligophenylenes (OPPs) symmetrically end-capped with diphenylamino groups and asymmetrically end-capped with anthryldiphenylamino groups were successfully synthesized by a convergent approach with use of palladium-catalyzed homo- and cross-coupling of arylboronic acids. The absorption maxima of both diphenylamino end-capped OPP series do not vary with the chain length although the molar absorptivities increase sequentially. On the other hand, the emission maxima slightly shift to longer wavelengths when the phenylene unit increases in the series. All the diphenylamino end-capped oligomers exhibit very large fluorescence quantum yields (81-89%). They also exhibit low first ionization potentials, corresponding to the oxidation of the triarylamino moiety, which are essentially unaffected by the oligomeric length extension. The good thermal stabilities of these oligomers allowed the fabrication of multilayer light-emitting devices and their investigations. 相似文献
982.
Wen Ye LI Ying Li WEI Wen Ting AN Shao Min SHUANG* Man Shing WONG* School of Chemistry Chemical Engineering Shanxi University Taiyuan Department of Chemistry Hong Kong Baptist University Hong Kong 《中国化学快报》2006,17(12)
A variety of analytical techniques have been employed to investigate the interaction of calixarene with amino acids including 1HNMR1, MALDI-MS2 and calorimetric titration3. Furthermore, spectrofluorometry is another excellent method for its convenience an… 相似文献
983.
984.
Synthesis and structural characterization of metal complexes based on pyrazole/imidazolium chlorides
Hon Man Lee Pei Ling Chiu Ching-Han Hu Chun-Liang Lai Yi-Chun Chou 《Journal of organometallic chemistry》2005,690(2):403-414
A series of imidzoalium salt, L · HCl, for the potentially bidentate pyrazole/N-heterocyclic carbene was synthesized. Reactions of a 2:1 mixture between L · HCl bearing bulky N-substitution and Ag2O produced Ag(L)Cl, whereas a novel compound with unique stoichiometry AgL2(AgCl)0.5Cl was produced from L · HCl bearing N-methyl group under identical condition. Reactions of L · HCl with PdCl2 produced zwitterionic PdIICl3L · H. Selected structural determinations on L · HCl, Ag(L)Cl, AgL2(AgCl)0.5Cl, and PdIICl3L · H revealed intriguing crystal chemistry in which the less-stable gauche rotamers were obtained exclusively. A preliminary application of the zwitterionic complexes, PdIICl3L · H, in Heck coupling reaction of aryl bromide with n-butyl acrylate shows effective activity. 相似文献
985.
Pingxuan Jiao Shouxin Wang Shuobin Liang Man Li Qianqian Gao Dezhong Ji Yingying Chen Haiwei Li Fuxiang Ran Yongmin Zhang Lihe Zhang Demin Zhou Sulong Xiao 《中国化学快报》2019,30(3):690-693
Four water-soluble β-CD-pentacyclic triterpene conjugates were synthesized via ester and amide linkages. All the conjugates showed lower hydrophobicity (AlogP) than their parent. 相似文献
986.
Chang Sook Kim Gwang Hyun Han Jin Man Kim Jin Jung 《Photochemistry and photobiology》1993,57(S1):1069-1074
Abstract— A comparative study was carried out on the in situ susceptibilities to photoinactivation of the photosystem I (PS I) and II (PS II) complexes of spinach thylakoids treated with efficient type II sensitizers. While the presence of the exogenous sensitizers caused a substantial increase in the extent of photoinactivation of whole chain electron transport, it did not affect PS I activity of thylakoids in light but exerted an enhanced photoinactivating effect only on PS II. The measurements of the action spectrum for the inhibition of PS II activity of the sensitizer-incorporated thylakoids and that for the generation of singlet oxygen (1 O2 ) from them revealed that photosensitized inactivation of PS II is directly related to the photoproduction of 1 O2 in thylakoid membranes. The results obtained in the present work clearly demonstrate an exceptional sensitivity of PS II to 1 O2 , providing circumstantial evidence that high light-induced damage to PS II may result from photosensitization reactions mediated by 1 O2 , which is not necessarily produced within the PS II complex. 相似文献
987.
Zusammenfassung Durch Oxydation von Kobalt(II)salz-Lösungen in Anwesenheit von Dimethylglyoxim und aromatischen Diaminen wurden unter doppelter Umsetzung 41 Salze der [Co(HD)2(o-Phenylendiamin)2]+, [Co(HD)2(m-Phenylendiamin2])+, [Co(HD)2-(2-Methyl-p-phenylendiamin)2]+ und [Co(HD)2(N-Dimethyl-p-phenylendiamin)2]+-Kationen erhalten. Die Koordination von zwei Diaminliganden im Kobalt(III)-bis-dimethylglyoximin-Kern bestätigt dietrans-Konfiguration der [Co(HD)2(Diamin)2]+-Komplexe. Diese Annahme wurde auch durch UR-spektroskopische Untersuchung bestätigt.
Mit 2 Abbildungen 相似文献
On-dioxime complexes of transition metals, XXXVII. Cobalt(III)-dimethylglyoxime complexes with aromatic diamines
The oxidation of cobalt(II) salts in presence of dimethyl-glyoxime and aromatic diamines, has been studied. A series of 41 novel complex salts of the cations [Co(HD)2(o-phenylendiamine)2]+, [Co(HD)2(m-phenylendiamine)2]+, [Co(HD)2(2-methyl-p-phenylendiamine)2]+ and [Co(HD)2(N-dimethyl-p-phenylendiamine)2]+ has been prepared and characterized by means of double decomposition reactions.The coordination of 2 diamine molecules to the Co(III)-dimethylglyoximine-skelet confirms thetrans-configuration of the [Co(HD)2(diamine)2 + complexes.
Mit 2 Abbildungen 相似文献
988.
Summary of main observation and conclusion Electrophilic trifluoromethylthiolation has emerged as an important and efficient methodology for installing the SCF3 moiety onto an array of organic molecules.Due to the low reactivities of trifluoromethylthiolating reagents,these transformations often require activation through an exogenous Lewis/Br0nsted acid.We report herein the quantification of the activation capabilities of Lewis/Br0nsted acids for trifluoromethylthiolating reagents through computing the differenee in trifluoromethylthio cation donor ability(Tt+DA)between the"activated"and"unactivated"reagent.A moderate correlation is found to exist between the activation capability and Lewis acidity. 相似文献
989.
C. K. Man Y. H. Zheng P. K. Mak 《Journal of Radioanalytical and Nuclear Chemistry》1996,212(2):151-160
The trace element profiles of the scalp hair of NPC patients, aged between 30 and 69, were measured using neutron activation analysis and compared with those of normal healthy people within the same age bracket. The washing method of using detergent and washing powder was found to be comparable to that of using ether. Difference in the mean concentration of each element in the two groups was tested by Student's t-test. A significantly lower value of strontium (Sr) and significantly higher values of arsenic (As), iron (Fe) and vanadium (V) were found in the hair of NPC patients. The relative values of As and Fe found were consistent with the results of other findings on NPC patients, using different measuring methods. The V content in the hair of NPC patients was three times that of healthy people. 相似文献
990.
Lee JA Moon HR Kim HO Kim KR Lee KM Kim BT Hwang KJ Chun MW Jacobson KA Jeong LS 《The Journal of organic chemistry》2005,70(13):5006-5013
On the basis of the biological activity of neplanocin A and apio-dideoxyadenosine (apio-ddA), novel apio-neplanocin A analogues 5a-d, combining the properties of two nucleosides, were stereoselectively synthesized. The apio moiety of the target nucleosides 5a-d was stereoselectively introduced by treating lactol 10 with 37% formaldehyde in the presence of potassium carbonate. The carbasugar moiety of neplanocin A was successively built by exposing diene 12 on a Grubbs catalyst in methylene chloride. The final nucleosides 5a-d were synthesized from the condensation of the glycosyl donor 14 with nucleic bases under the standard Mitsunobu conditions. Similarly, apio-aristeromycin 6 and (N)-apio-methanocarbaadenosine 7 were derived from the common intermediate 13 using catalytic hydrogenation and Simmons-Smith cyclopropanation as key steps. All of the final nucleosides 5a-d, 6, and 7 did not show significant inhibitory activity against S-adenosylhomocysteine hydrolase (SAH) up to 100 muM, maybe due to the absence of the secondary hydroxyl group at the C3'-position, which should be oxidized by cofactor-bound NAD(+). However, apio-neplanocin A (5a) showed potent and highly selective binding affinity (K(i) = 628 +/- 69 nM) at the A(3) adenosine receptor without any binding affinity at the A(1) and A(2A) adenosine receptors. In conclusion, we have first developed novel carbocyclic nucleosides with unnatural apio-carbasugars using stereoselective hydroxymethylation and RCM reaction and also discovered a new template of human A(3) adenosine receptor agonist, which play a great role in developing new A(3) adenosine receptor agonist as well as in identifying the binding site of the receptor. 相似文献