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31.
The isolation of cinchonicine-derived alkaloids epicinchonicinol (1), cinchonidicinol (2) and a mixture of dihydrocinchonicinol and dihydrocinchonidicinol (3) from the dried bark of Ladenbergia oblongifolia, is reported along with (1)H and (13)C-NMR data. 相似文献
32.
Capillary gas chromatographic-mass spectrometric determination of fluoroacetate residues in animal tissues 总被引:2,自引:0,他引:2
H H Casper T L McMahon G D Paulson 《Journal of the Association of Official Analytical Chemists》1985,68(4):722-725
A method for the quantitative determination of fluoroacetate (FAC) residues in animal tissues is described. The procedure involves tungstic acid extraction, partitioning into ethyl acetate, evaporation of ethyl acetate, derivatization with pentafluorobenzyl bromide (PFB), and analysis of the resulting derivative (PFB-FAC) by capillary gas chromatography-mass spectrometry (CGC-MS) with specific ion monitoring (SIM). The tungstic acid system extracted 96.8 +/- 4.2% of the endogenous 14C-1080 residues in rat tissues. Recovery of FAC during the extraction, purification, and derivatization procedures is established by use of a 14C-FAC spike. 1,2-Dibromobenzene is used as an internal standard for the CGC-MS analysis. PFB-FAC is identified on the basis of comparative retention times and the relative intensities of m/z 257.9 and 181.0. PFB-FAC is quantitated by comparing the response at m/z 257.9 to a PFB-FAC standard curve. Routine sensitivity of the method allows determination of 10 ppb fluoroacetate in tissue. 相似文献
33.
H H Casper M E Mount R E Marsh R H Schmidt 《Journal of the Association of Official Analytical Chemists》1986,69(3):441-442
Fluoroacetate residues in various tissues of 1080-poisoned ground squirrels and coyotes are listed. The tissues (excluding the stomach) of squirrels poisoned with an average of 0.8 mg 1080/kg (low dose) contained from 182 to 1309 ppb fluoroacetate. In squirrels poisoned with an average of 4.8 mg 1080/kg (high dose), the tissue residues ranged from 535 to 9754 ppb fluoroacetate. Tissues from coyotes which died after consuming 1080-poisoned ground squirrels were also analyzed for fluoroacetate residues. Residues in these coyote kidneys and livers ranged from less than 10 ppb to 95 ppb fluoroacetate. The residue findings in this research indicate that a diagnostic assay for 1080 in tissues must be reliable at 10 ppb (or less) fluoroacetate. 相似文献
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H H Casper A D Alstad D B Tacke L J Johnson W E Lloyd 《Journal of veterinary diagnostic investigation》1989,1(2):116-119
Sweet clover poisoning in cattle is caused by an anticoagulant (dicumarol) that is formed in moldy sweet clover hay. Previous experiments with vitamin K3 and vitamin K1 in therapy trials indicated that vitamin K1 was effective in reducing prothrombin times but vitamin K3 was not. As a possible alternative in the use of toxic sweet clover hays, vitamin K3 was evaluated to see if it would prevent hemorrhagic crises when fed to cattle consuming toxic sweet clover hay. Vitamin K3 levels of 0, 0.45, 4.5, 11, and 45 mg/kg body weight/day were fed to 173-235-kg steers consuming toxic (40-50 ppm dicumarol) sweet clover. The 45-mg K3/kg/day supplement was not palatable and had to be discontinued. The 0.45, 4.5, and 11-mg K3/kg/day supplements did not significantly reduce the prothrombin times as compared to the 0-mg K3/kg/day group. 相似文献
36.
Osama G. Mohamed Sadaf Dorandish Rebecca Lindow Megan Steltz Ifrah Shoukat Maira Shoukat Hussein Chehade Sara Baghdadi Madelaine McAlister-Raeburn Asad Kamal Dawit Abebe Khaled Ali Chelsey Ivy Maria Antonova Pamela Schultz Michael Angell Daniel Clemans Timothy Friebe David Sherman Anne M. Casper Paul A. Price Ashootosh Tripathi 《Marine drugs》2021,19(8)
37.
The purpose of this study is to estimate the intra EU trade value of wood products and examine the factors affecting the trade flow. A gravity model is used to estimate the factors affecting the trade flow. The study uses a panel data set, with fixed effects, on trade in two forest products between 28 EU member countries over the period 2005–2014. The forest products are woodchips and particles (HS4401) and industrial roundwood (HS4403). For HS4401, the result suggests that the GDP of both the exporting and importing countries affect the trade flow positively (0.64 and 0.36, respectively). For HS4403, the GDP of the exporting countries affect have a negative effect (?0.69), while the GDP of the importing countries have a positive effect (0.80). In a second step, the estimated parameters are used to forecast the trade up until year 2030. The forecast suggests an increase in the trade by 47 per cent. This suggests an improved efficiency in reaching the EU climate and energy targets. That is, the trade in biofuels is expected to increase due to economic growth, which in turn works towards achieving the renewable and CO2 emission targets in Europe. 相似文献
38.
Thermal plasticity potentially mediates the interaction between host Chilo partellus Swinhoe (Lepidoptera: Crambidae) and endoparasitoid Cotesia flavipes Cameron (Hymenoptera: Braconidae) in rapidly changing environments 下载免费PDF全文
Reyard Mutamiswa Frank Chidawanyika Casper Nyamukondiwa 《Pest management science》2018,74(6):1335-1345
39.
Interactions between populations of the calanoid copepod Acartia tonsa Dana and the harpacticoid copepod Tisbe holothuriae Humes in mixed cultures of live feed for fish larvae 下载免费PDF全文
Benni W Hansen Emil Boesen Ole B Brodnicke Natasja L Corfixen Per M Jepsen Stephanie M Larsen Casper D Læssøe Pernille S Munch Peder K F Nielsen Jørgen Olesen Bent Vismann Birgitte Nilsson 《Aquaculture Research》2018,49(3):1274-1283
Copepods are considered high quality live feed for fish larvae due to their large within species size span, swimming pattern triggering hunting behaviour, and complete biochemical profile. In a continuous cultivation system aiming at the planktonic calanoid Acartia tonsa an intruding harpacticoid frequently appears. We experimentally evaluate how the interaction from the semi‐benthic Tisbe holothuriae is affecting our cultures and ask whether the two copepod‐species are expected to pose competitive exclusion or co‐exist long‐term. This is pursued by establishing ~40 days mono‐ and mixed copepod cultures reared in a stationary setup (S) theoretically advantageous for T. holothuriae and a rotating setup (R) with organisms kept in suspension by use of a plankton wheel, theoretically advantageous for A. tonsa. The carrying capacities of A. tonsa in either mono‐ or mixed cultures are not affected whether the copepods are subject to S or R treatment. Only exception is the S‐setup containing mixed culture were A. tonsa obtains a significantly lower carrying capacity compared with A. tonsa alone in R‐setup. The mono‐ and mixed cultures of T. holothuriae are, however, highly negatively affected by the R setup compared with S setup. A long‐term solution to limit the presence of T. holothuriae is to apply turbulence level in a classical stagnant tank setup to an extend that suppress T. holothuriae and simultaneously allow algae in suspension as food for A. tonsa, make their eggs sediment as well as minimize risk of benthic‐predation on eggs. 相似文献
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