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21.
Moon HR Park AY Kim KR Chun MW Jeong LS 《Nucleosides, nucleotides & nucleic acids》2007,26(10-12):1653-1657
Novel L-bicyclocarba-d4T (1), an enantiomer of D-N-MCd4T has been enantiopurely synthesized as a potent anti-HIV agent starting from (R)-epichlorohydrin using tandem alkylation, chemoselective reduction of ester in the presence of lactone functional group, Grignard reaction, RCM reaction, and Mitsunobu reaction as key steps. L-N-MCd4T (1) was found to be very potent anti-HIV-1 (EC(50) = 6.76 microg/mL) agent with no cytotoxicity. 相似文献
22.
Jeong LS Gunaga P Kim HO Tosh DK Lee HW Choe SA Moon HR Gao ZG Jacobson KA Chun MW 《Nucleosides, nucleotides & nucleic acids》2007,26(8-9):1011-1014
Stereoselective functionalization of the 1'-position of 4'-thionucleosides was achieved using a stereoselective S(N)2 reaction controlled by 5-membered ring coordination. 相似文献
23.
Jeong LS Lee JA Kim HO Tosh DK Moon HR Lee SJ Lee KM Sheen YY Chun MW 《Nucleosides, nucleotides & nucleic acids》2007,26(8-9):1021-1024
Novel 2'-C-methyl-cyclopropyl-fused carbocyclic nucleosides as potential anti-HCV agents were stereoselectively synthesized, utilizing regioselective cleavage of the isopropylidene group and cyclic sulfate chemistry as key steps. 相似文献
24.
Chun MW Lee HW Kim JH Kim HO Lee KM Pal S Moon HR Jeong LS 《Nucleosides, nucleotides & nucleic acids》2007,26(6-7):729-732
Homo-apioneplanocin A (1) as a potential inhibitor of S-adenosylhomocysteine hydrolase was synthesized from D-ribose, employing stereoselective hydroxymethylation, regioselective oxidation, and regio- and chemoselective hydroboration as key steps. 相似文献
25.
26.
Han E Paulus MP Wittmann M Chung H Song JM 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2011,879(7-8):541-547
The questions of whether the dose of drug that is consumed corresponds to drug concentration levels in hair and how results of hair analyses can be interpreted are still debated. The aim of this study was to investigate (1) whether there is a correlation between doses of Methamphetamine (MA) use and MA concentration levels in hair and (2) whether results of hair analyses can be used to estimate dose, frequency, and patterns of MA use. In this study, segmental hair analysis was performed through consecutive 1cm as well as 1-4 cm (=3 cm) segmental hair lengths. MA dependent individuals (n=9) provided information on doses (0.25-4 g/day) of MA use as well as the frequency of MA use. The concentrations of MA and its metabolite amphetamine (AP) in hair were determined using gas chromatography/mass spectrometry (GC/MS). One-way analysis of variance (ANOVA) test was performed to evaluate whether MA and AP concentrations in consecutive 1cm length segmental hair were consistent with the history of MA use. The cumulative doses of MA use calculated from the daily dose and the frequency during 1-4 months were well correlated to the concentrations of MA and AP in 1-4 cm segmental hair length (correlation coefficient, r=0.87 for MA and r=0.77 for AP). The results from this study show the patterns and histories of MA use from MA dependent individuals and could assist in the interpretation of hair results in forensic toxicology as well as in rehabilitation and treatment programs. 相似文献
27.
Xiaodong Li Myong Jong Yi Yowhan Son Pil Sun Park Kyeong Hak Lee Yeong Mo Son Rae Hyun Kim Mi Jeong Jeong 《Journal of Plant Biology》2011,54(1):33-42
This study examined the biomass and carbon pools of the main ecosystem components in an age sequence of five Korean pine plantation
forest stands in central Korea. The C contents in the tree and ground vegetation biomass, coarse woody debris, forest floor,
and mineral soil were estimated by analyzing the C concentration of each component. The aboveground and total tree biomass
increased with increasing stand age. The highest C concentration across this chronosequence was found in the tree branch while
the lowest C concentration was found in the ground vegetation. The observed C contents for tree components, ground vegetation,
and coarse woody debris were generally lower than the predicted C contents estimated from a biomass C factor of 0.5. Forest
floor C content was age-independent. Total mineral soil C content appeared to decline initially after establishing Korean
pine plantations and recover by the stand age of 35 years. Although aboveground tree biomass C content showed considerable
accumulation with increasing age, the relative contribution of below ground C to total ecosystem C content varied substantially.
These results suggest that successional development as temporal factor has a key role in estimating the C storage in Korean
pine plantation forests. 相似文献
28.
Moon HR Lee KM Lee JH Lee SK Park SB Chun MW Jeong LS 《Nucleosides, nucleotides & nucleic acids》2005,24(5-7):707-708
Four 5'-substituted fluoro-neplanocin A analogues la-d were designed and synthesized, and the inhibitory activity against SAH was in the following order: NH2 > SH > F, N3, indicating a hydrogen bonding donor is essential for inhibitory activity. 相似文献
29.
Genome sequence of Leuconostoc argentinum KCTC 3773 总被引:1,自引:0,他引:1
Leuconostoc argentinum is one of the most prevalent lactic acid bacteria present during the manufacturing process of kimchi, the best-known traditional Korean dish. Here, we present the draft genome sequence of type strain KCTC 3773 of Leuconostoc argentinum (1,720,683 bp, with a G+C content of 42.9%), which consists of 98 large contigs (>100 bp in size). 相似文献
30.
Background and Aims For rare endemics or endangered plantspecies that reproduce both sexually and vegetatively it iscritical to understand the extent of clonality because assessmentof clonal extent and distribution has important ecological andevolutionary consequences with conservation implications. Asurvey was undertaken to understand clonal effects on fine-scalegenetic structure (FSGS) in two populations (one from a disturbedand the other from an undisturbed locality) of Echinosophorakoreensis, an endangered small shrub belonging to a monotypicgenus in central Korea that reproduces both sexually and vegetativelyvia rhizomes. Methods Using inter-simple sequence repeats (ISSRs) asgenetic markers, the spatial distribution of individuals wasevaluated using Ripley's L(d)-statistics and quantified thespatial scale of clonal spread and spatial distribution of ISSRgenotypes using spatial autocorrelation analysis techniques(join-count statistics and kinship coefficient, Fij) for totalsamples and samples excluding clones. Key Results A high degree of differentiation betweenpopulations was observed (ST(g) = 0·184, P < 0·001).Ripley's L(d)-statistics revealed a near random distributionof individuals in a disturbed population, whereas significantaggregation of individuals was found in an undisturbed site.The join-count statistics revealed that most clones significantlyaggregate at 6-m interplant distance. The Sp statistic reflectingpatterns of correlograms revealed a strong pattern of FSGS forall four data sets (Sp = 0·0720·154), butthese patterns were not significantly different from each other.At small interplant distances (2 m), however, jackknifed 95% CIs revealed that the total samples exhibited significantlyhigher Fij values than the same samples excluding clones. Conclusion The strong FSGS from genets is consistentwith two biological and ecological traits of E. koreensis: bee-pollinationand limited seed dispersal. Furthermore, potential clone matesover repeated generations would contribute to the observed highFij values among genets at short distance. To ensure long-termex situ genetic variability of the endangered E. koreensis,individuals located at distances of 1012 m should becollected across entire populations of E. koreensis. 相似文献