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831.
Abid Hussain Ming-Yi Tian Yu-Rong He Yan-Yuan Lei 《Journal of invertebrate pathology》2010,104(3):166-171
Insect-passaged cultures of entomopathogenic fungi grown on potato dextrose agar media have been shown to have altered virulence and profiles of volatile compounds. The present study demonstrated the pathogenic status of FS0 (in vitro) and FS1 and FS2 (insect-passaged cultures grown on PDA) cultures of Metarhizium anisopliae (strains 406 and 02049) and Beauveria bassiana by a non-choice assay, in which filter paper was inoculated with fungal spores at a concentration of 1 × 107 spores/ml. The FS1 and FS2 cultures of M. anisopliae strain 02049 and B. bassiana produced conidia with high virulence, and the volatile profiles of these conidia comprised relatively lower percentages of branched-alkanes than conidia from the FS0 cultures. In contrast, the conidia from an FS0 culture of M. anisopliae strain 406 had somewhat elevated virulence levels, but their volatile profile had <2% branched-alkanes. The FS1 and FS2 cultures of M. anisopliae strain 406 did not gain virulence, and these cultures showed a decline in virulence along with major alteration of their volatile profiles. Their volatile profiles mainly comprised branched-alkanes. The volatile profiles of the FS1 and FS2 cultures lacked n-tetradecane, which was an important component of all the virulent cultures. Four compounds, 2-phenylpropenal, 2,5,5-trimethyl-1-hexene, n-tetradecane and 2,6-dimethylheptadecane, were detected only from the virulent cultures, suggesting that low LT50 values were probably due to the production of these compounds. This is the first report to characterize volatiles from FS0, FS1 and FS2 cultures of entomopathogenic fungi; its utility in different aspects opens an interesting area for further investigations. 相似文献
832.
833.
Heidi E.M. Dobson Juan Arroyo Gunnar Bergström Inga Groth 《Biochemical Systematics and Ecology》1997,25(8):685-706
To improve our understanding of the floral biology, pollination, and systematics of the genus Narcissus, a comparative study was made of flower volatiles from nine species native to southern Spain using headspace collection and GC-MS analysis. The species fell into three fragrance types based on the identity of their major volatiles. In all but one species the fragrances consisted mainly of monoterpene isoprenoids mixed with benzenoids: in six species trans-ß-ocimene occurred in high proportions, in two others it was lacking; the last species had a fragrance dominated by fatty acid derivatives, mixed with terpenoids. Two of the species showed marked intraspecific variation in many of their volatiles. When the volatile data matrix of all species was subjected to cluster analyses and the resulting phenetic trees compared with currently recognized taxonomic groups, there was no congruence at the subgeneric level. However, there was considerable agreement at the sectional level, although in most sections we studied only a single species. This apparent agreement was stronger when the volatiles were analyzed according to shared biosynthetic pathways rather than treated individually, pointing to the higher value of using biosynthetic pathways for uncovering and confirming phenetic, and probable evolutionary, relationships among species. In terms of possible selective pressures from pollinators in shaping fragrance chemistry, available information on the pollination of our species suggested an association between fragrance and types of pollinators. Two pollinator-fragrance groups were apparent: (1) species pollinated by insects that include butterflies and moths displayed fragrances containing volatiles typical of moth-pollinated flowers, most particularly indole combined with high amounts of esters, and (2) species visited exclusively by insects other than butterflies and moths, especially by bees and flies, had fragrances lacking this combination of volatiles. Narcissus assoanus was unusual among our species in having both fragrance chemotypes. Future pollination studies of Narcissus in the field are needed to test the reliability and predictability of the proposed fragrance-pollinator associations. 相似文献
834.
GU Jian-Long Guy SS NJATENG LI Zhi-Jian ZHANG Hong-Xia DAI Qin DU Zhi-Zhi 《Plant Diversity》2014,36(1):116-122
Essential oils obtained by hydrodistillation from leaves of Laggera pterodonta collected from four different locations (Kunming, Lijiang, Puer and Xinping) in Yunnan, China, were analyzed using GC MS and GC FID. The number of compounds identified in each sample was 39, 37, 33 and 44, respectively, representing 9332% (Kunming), 8057% (Lijiang), 9224% (Puer) and 9385% (Xinping) of total essential oils. Chemical compositions of essential oils differed between sample locations: thus, those from Kunming were rich in benzenoid compounds (3806%) while those from Lijiang and Puer were largely dominated by sesquiterpenes (1989% and 4465% respectively) and sesquiterpenes oxide (4085% and 3511%, respectively), and those from Xinping contained a high proportion of monoterpene hydrocarbons and sesquiterpene hydrocarbons (4223% and 3325% respectively) (7548%). The results of tests on the antimicrobial activities of essential oils indicated that chemical composition was affected by environmental variation causing differences in sensitivity to microbes among samples. 相似文献