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81.
82.
The responses of onion (Allium cepa). Veronica persica, Matricaria matricarioides and Stellaria media to post-emergence applications of methazole were measured in field and glasshouse experiments. Stellaria media was the most susceptible species and V. persica the least. Plants of all species became more tolerant the larger they were at the time of treatment, and this was most pronounced in onion. Onion generally retained less spray per unit of dry weight than the other three species and retention was less on old compared with young plants, whereas with the weed species, this did not change appreciably with age. There was a progressive increase in the amount of structured crystalline wax on successive onion leaves which resulted in larger contact angles between droplets and the leaf surfaces and lower spray retention per unit of dry weight. There was less wax development on the leaf surfaces, increased spray retention, and increased susceptibility to methazole in onion treated pre-emergence with ethofumesate thus confirming that these factors are interrelated. While the increased tolerance of onion to methazole with age could be explained in part by decreased retention of herbicide, this was not so for the weed species, and other factors must determine their change in tolerance with age.  相似文献   
83.
Soil incorporated. pre-sowing application of trifiuralin in cotton or of benfluralin in gruundnut, each at 1–68 kg a.i., ha, cut labour requirement for handweeding to levels where the tenant could he largely independent of hired labour, Economic returns from a combination of these herbicides plus supportive hand- weeding for herbicide-resistant species compared favourably with those from hand- weeding only as presently recommended. Application and incorporation of trifluralin and benfluralin fited well into existing practices for seedbed preparation and any likely modifications of these. There was no evidence of crop phytoxicity and crop maturity was not affected. Residue analysis indicated no soil residue problems for crops in rotations and no residues were detected in crop seed. Trifluralin applied many months in advance of cotton planting in the dry season, did not start to disappear until the soils were wetted just before couon planting.  相似文献   
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W. W. DONALD 《Weed Research》1992,32(4):259-266
Three herbicide treatments were applied each year over a period of 4 years to Cirsium arvense (L.) Scop, infestations in no-till spring wheat (Triticum aestivum L.) in North Dakota, USA. Both chlorsulfuron at 30 g ai ha?1+a non-ionic surfactant and a mixture of clopyralid+2,4-D at 70+280 g ai ha?1 gradually reduced Cirsium arvense shoot density, root biomass, and adventitious root buds over the 4-year treatment period in two trials. These two treatments did not merely induce adventitious root buds to become dormant. They virtually eliminated roots to a depth of 50 cm by year 4. Tribenuron methyl at 10 g ai ha?1+ a non-ionic surfactant was less effective in reducing shoot density and root biomass. Lutte herbicide contre les racines et les tiges de Cirsium arvense (L.) Scop, dans du bli de printemps non laboure (Triticum aestivum L.) Trois traitements herbicides ont été appliqués chaque année pendant 4 ans, contre des infestations de Cirsium arvense (L.) Scop, dans du blé de printemps (Triticum aestivum L.) non labouré dans le Dakota Nord, USA. Tant le chlorsulfuron à 30 g m.a. ha?+un surfactant nonionique qu'un mélange de clopyralide+2,4-D à 70+280 g m.a. h? ont reduit progres-sivement la densité des pieds de Cirsium arvense, la biomasse racinaire, et les bourgeons racinaires adventices pendant les 4 années de traitements dans les 2 essais. Ces traitements ont à peu près éliminé les racines sur une profondeur de 50 cm en 4 ans. Ces deux traitements n'ont pas induit de dormance des bourgeons racinaires adventices. Le tribenuron methyl à 10 g m.a. ha?+un surfactant non ionique a été moins efficace dans la réduction de la densité de plante et de la biomasse racinaire. Chemische Bekämpfung von Cirsium arvense (L.) Scop, in direktgesätem Sommerweizen (Triticum aestivum L.) In direktgesäter Sommerweizen (Triticum aestivum L.) wurdel in North Dakota. USA, Bestände von Cirsium arvense (L.) Scop, über 4 Jahre jährlich 3 Herbizidbehandlungen unterzogen. Sowohl Chlorsulfuron mit 30 g AS ha?1 nichtionischem Netzmittel als auch eine Mischung von Clopyralid+2,4D mit 70+280 g AS ha?1 verringerten die Sproßdichte der Acker-Kratzdistel, die Wurzelbiomasse und die Adventivknospen an den Wurzeln in 2 Ver-suchen graduell. Durch diese beiden Behand-lungen wurden nicht nur die Adventivknospen dormant, sondem auch die Wurzeln bis zu einer Tiefe von 50 cm bis zum 4. Jahr fast ganz elimi-niert. Tribenuron-methyl mit 10 g AS ha?1 nichtionischem Netzmittel war hinsichtlich der Reduktion von Sproßdichte und Wurzelbiomasse weniger wirksam.  相似文献   
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以Zn含量较高的猪粪为原料进行了90d好氧堆肥,以采自陕西省永寿县养马庄的典型缺锌土壤为供试土样,通过大豆盆栽试验研究了该有机肥对大豆生长的影响,并以污染指数评价法和地积累指数评价了施用该有机肥对土壤中重金属的累积环境风险。结果表明:经过90d的高温好氧堆制,获得了氮磷钾丰富的堆肥产品,且堆肥中未检测出Ni、Cd、Cr、Pb、Hg和As等有害重金属,仅含Cu256.3mg.kg-1、Zn474.4mg.kg-1。与对照相比,随着有机肥施用量的增加,大豆生物量和产量逐渐增加,并在肥土比10%时达到最高,大豆产量比对照提高了206.7%,大豆根系重量提高了94.2%,大豆茎叶(含荚壳)提高了94.0%;大豆籽粒中Zn含量则随着有机肥施用量的增加而逐渐增加,并在40%时籽粒Zn含量高达49.33mg.kg-1;施用堆肥后,土壤EC、Zn和Cu全量、Zn和Cu有效量均随着堆肥使用量的增加而增加,而土壤pH则随着堆肥比例的增加,从8.46逐渐降低到7.44。污染指数评价法和地积累指数评价法表明,当茬堆肥施用量不超过5%时,不会对该缺锌土壤造成重金属污染。研究显示,适量施用该堆肥能显著促进大豆的茎叶和根系生长,同时提高籽粒产量和籽粒中的Zn含量。对于供试缺锌土壤,施用该富锌有机肥可以明显补充土壤锌。  相似文献   
88.
The primary goal of this pilot study was to assess, the efficacy of a new nutraceutical, 4CYTE™ Epiitalis® Forte, containing, as a standalone, a proprietary plant oil extract, Epiitalis, in dogs presenting with signs of osteoarthritis (OA). Fifty dogs aged 9.2 (±3.2) years with signs of naturally occurring OA were included in this report. They were free of other comorbidities and were not on any medications except for those utilised for managing their OA. In these dogs, the current treatments were continued to avoid any sudden changes in their disease management. The effects of the 4CYTE Epiitalis Forte were assessed both at the beginning and at the end of a 1 month-long treatment period. The evaluation consisted of an objective lameness assessment (TPI%[total pressure index]) using a gait analysis (GAITRite® Portable Walkway System) and a subjective quality-of-life questionnaire, the Helsinki Chronic Pain Index (HCPI). Additional exploratory objective measurements included the Symmetry Index (SI) and the fore/hind limb ratio (T/P TPI%). Of dogs, 74% (34/46) registered a numerical improvement in TPI% in their worse limb. In addition, of the 93.5% of the dogs that demonstrated improvement in their HCPI scores by at least 5% on the quality-of-life questionnaire, 79% demonstrated improvements in gait based on TPI%. Finally, there were improvements measured in both exploratory objective endpoints SI and T/P TPI%. These encouraging results will be used to develop a protocol for a follow-up placebo-controlled randomised study to confirm the efficacy of this new nutraceutical for dogs suffering from OA.  相似文献   
89.
Widespread spontaneous evacuation, the tendency for people to evacuate even when not advised to do so, has been highlighted as one of the likely behavioral responses to a nuclear power plant emergency. Utility company representatives contend that protective action advisories can be structured so as to stifle the magnitude and geographic extent of spontaneous evacuation. Data from a utility-company-sponsored telephone survey of households on Long Island, New York, where the Shoreham Nuclear Power Station is located, are used in this paper to test this proposition. Analyses of responses given to three sets of increasingly serious reactor accident scenarios, with and without information instructing people what protective actions to take, raise serious questions about the ability of emergency notification messages to affect human behavior in a radiological emergency. The results suggest firstly, that even if people me specifically advised not to evacuate, most would be inclined to do so; and secondly, that attempts to stifle the propensity to evacuate among those who are not at risk are likely to increase the propensity to stay behind among those who are at risk and should evacuate.  相似文献   
90.
ABSTRACT This article reviews methodological issues confronting authors and users of economic impact studies of public colleges and universities. Questions addressed include the following: How should economic impact of regional public colleges and universities be defined? What considerations should govern the definition or the geographical study area? How should tax support of publicly supported institutions be addressed? The article includes perspectives from recent literature considering these questions from both short-term and long-term perspectives. Resolution of these issues depends upon careful delineation and communication of the alternative states of world between which the hypothetical impact is measured.  相似文献   
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