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71.
Jaffee BA 《Phytopathology》2000,90(5):498-504
In previous studies, growth of Hirsutella rhossiliensis from pelletized assimilative hyphae was reduced by other soil organisms. In the current study, sensitivity to this biotic inhibition was compared when the fungus was added to soil as pelletized hyphae or as fungus-parasitized nematodes. The hypothesis was that the natural inoculum, the parasitized nematode, would be less sensitive than the artificial inoculum, pelletized hyphae. The soil was heated to 60 degrees C for 2 h to remove putative antagonists or was not heated. The soil was packed into vials (17 cm(3)) and kept at 20 degrees C in the laboratory or packed into cages (PVC pipe sealed at the ends with 480-mum pore mesh, 80 cm(3)) and buried 22 cm deep in a vineyard. After 2 or 4 weeks, assay nematodes were added to the vials or cages (recovered from the vineyard), respectively. The assay nematodes were extracted from soil after 2.0 or 2.5 days and examined for adhesive conidia of H. rhossiliensis. Consistent with the hypothesis, H. rhossiliensis was quite sensitive to biotic inhibition when formulated as pelletized hyphae but was insensitive to biotic inhibition when formulated as parasitized nematodes. These data suggest that the activity of the H. rhossiliensis pellet could be increased if the pellet better mimicked the natural inoculum. Similar experiments with the nematode-trapping fungus Arthrobotrys haptotyla, however, exhibited an opposite trend: A. haptotyla was more sensitive to biotic inhibition when added to soil as fungus-parasitized nematodes than as pelletized hyphae. Results from laboratory and field experiments were similar. 相似文献
72.
ABSTRACT Nematode-trapping fungi, nematodes, and microbial biomass were quantified in conventionally and organically managed field plots in the Sustainable Agriculture Farming Systems Project at the University of California at Davis. There were four replicate plots (0.135 ha per plot) for each management system, and plots were sampled three times each year for 2 years. The hypothesis that nematode-trapping fungi would be more abundant in organically managed plots was partially supported: the number of species of nematode-trapping fungi was slightly but significantly greater in organic than in conventional plots, two species (Arthrobotrys dactyloides and Nematoctonus leiosporus) were detected more frequently in organic plots, and the population densities of A. dactyloides and N. leiosporus were greater in organic than in conventional plots. Two other species (A. haptotyla and A. thaumasia), however, tended to be more numerous in conventional than in organic plots, and the total density of nematode-trapping fungi was similar in organic and conventional plots. Bacterivorous nematodes were more abundant and microbial biomass (substrate-induced respiration) was greater in organic than in conventional plots. Suppression of the root-knot nematode Meloidogyne javanica, as measured in a bioassay, was not related to management system or population density of nematode-trapping fungi but was positively related to microbial biomass. 相似文献
73.
Hinsdale BA 《Science (New York, N.Y.)》1887,10(239):112-113
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76.
Briviba K Stracke BA Rüfer CE Watzl B Weibel FP Bub A 《Journal of agricultural and food chemistry》2007,55(19):7716-7721
The present study was performed to compare the effects on antioxidant activity and on DNA damage of organic and conventionally produced apples grown under controlled conditions in human peripheral blood lymphocytes. Six healthy volunteers consumed either organically or conventionally grown apples (Golden Delicious, 1000 g) from two neighboring commercial farms in a double-blinded, randomized, cross-over study. The average content of total identified and quantified polyphenols in the organically and conventionally produced apples was 308 and 321 microg/g fresh weight, respectively. No statistically significant differences in the sum of phenolic compounds or in either of the polyphenol classes were found between the agricultural methods. Consumption of neither organically nor conventionally grown apples caused any changes in antioxidant capacity of low-density lipoproteins (lag time test), endogenous DNA strand breaks, Fpg protein-sensitive sites, or capacity to protect DNA against damage caused by hydrogen peroxide. However, a statistically significant decrease in the levels of endonuclease III sensitive sites and an increased capacity to protect DNA against damage induced by iron chloride were determined 24 h after consumption in both groups of either organic or conventionally grown apples, indicating the similar antigenotoxic potential of both organically and conventionally grown apples. 相似文献
77.
OBJECTIVE: To examine the pattern of intake of key foods and beverages of children aged 4-12 years and the association with weight status. DESIGN AND SETTING: A computer-assisted telephone interview was used to determine the intake of fruit, vegetables, packaged snacks, fast foods and sweetened drinks 'yesterday' and 'usually' as reported by parents/guardians of a representative sample of 2184 children from the Barwon South-Western region of Victoria, Australia. RESULTS: Children who consumed >2-3, >3-4 and >4 servings of fruit juice/drinks 'yesterday' were, respectively, 1.7 (95% confidence interval (CI) 1.2-2.2), 1.7 (95% CI 1.2-2.5) and 2.1 (95% CI 1.5-2.9) times more likely to be overweight/obese compared with those who had no servings of fruit juice/drink 'yesterday', adjusted for age, gender and socio-economic status (SES). Further, children who had > or = 3 servings of soft drink 'yesterday' were 2.2 (95% CI 1.3-3.9) times more likely to be overweight/obese compared with those who had no servings of soft drink 'yesterday', adjusted for age, gender and SES. In addition, children who 'usually' drank fruit juice/drinks twice or more per day were 1.7 (95% CI 1.2-2.4) times more likely to be overweight/obese compared with those who drank these beverages once or less per week, adjusted for age, gender and SES. Although fast foods and packaged snacks were regularly eaten, there were no associations between weight status and consumption of these foods. CONCLUSIONS: Intake of sweetened beverages was associated with overweight and obesity in this population of Australian schoolchildren and should be a target for intervention programmes aimed at preventing unhealthy weight gain in children. 相似文献
78.
de Brito ES de Araújo MC Alves RE Carkeet C Clevidence BA Novotny JA 《Journal of agricultural and food chemistry》2007,55(23):9389-9394
Many tropical fruits are rich in anthocyanins, though limited information is available about the characterization and quantification of these anthocyanins. The identification and quantification of anthocyanin pigments in four tropical fruits were determined by HPLC-MS/MS. Fruits studied included acerola (Malphigia emarginata), jussara (Euterpe edulis), jambol?o (Syzygium cumini), and guajiru (Chrysobalanus icaco). All four fruits were found to contain anthocyanin pigments. Anthocyanidin backbones included cyanidin, delphinidin, peonidin, pelargonidin, petunidin, and malvidin. Guajiru contained several acylated forms, while acerola, jussara, and jambol?o contained only nonacylated glycosides. These results demonstrate that these tropical fruits are rich in anthocyanins and that the anthocyanins are widely ranging in anthocyanidin backbone, glycosylation, and acylation. 相似文献
79.
The concentrations of monoamines in the hypothalamus were determined in yellow perch Perca flavescens before and after injection with lipopolysaccharide (LPS; 3 mg kg−1 fish weight) or saline to test for the presence of neurochemical changes potentially associated with changes in plasma cortisol
characteristic of intraperitoneal (ip) challenge with LPS. In the first experiment, yellow perch were injected with saline
or LPS and the hypothalamus removed and plasma sampled before and at 0.5, 1.5, 3.0, and 6 h after injection. Plasma cortisol
was elevated in both saline- and LPS-injected fish through 1.5 h after injection and returned to levels resembling pre-injection
by 3 h after injection. Significantly higher amounts of cortisol in plasma from LPS-injected relative to saline-injected fish
were observed 6 h following injection. A significant decrease relative to levels observed 0.5–3 h after handling was observed
in serotonin concentrations at 6 h following LPS and saline injection with a concomitant increase in the ratio of 5-hydroxyindoleacetic
acid:serotonin. In the second experiment, hypothalamic monoamines were sampled before and at 3, 6, 9, 12, and 24 h after injection
with LPS or saline. Significant increases from pre-injection levels were observed in the ratio 5-hydroxyindoleacetic acid:serotonin
at 9, 12, and 24 h after injection, but no differences were detected between LPS- and saline-injected fish. These results
support a model linking serotonergic system activation following handling stress, but no correlations with the sustained elevations
of plasma cortisol associated with inflammatory challenge were observed. 相似文献
80.