全文获取类型
收费全文 | 113篇 |
免费 | 9篇 |
专业分类
林业 | 6篇 |
农学 | 2篇 |
21篇 | |
综合类 | 8篇 |
农作物 | 7篇 |
水产渔业 | 5篇 |
畜牧兽医 | 54篇 |
园艺 | 4篇 |
植物保护 | 15篇 |
出版年
2023年 | 3篇 |
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 5篇 |
2019年 | 5篇 |
2018年 | 6篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 5篇 |
2014年 | 4篇 |
2013年 | 8篇 |
2012年 | 4篇 |
2011年 | 8篇 |
2010年 | 6篇 |
2009年 | 7篇 |
2008年 | 2篇 |
2007年 | 1篇 |
2006年 | 4篇 |
2005年 | 2篇 |
2004年 | 6篇 |
2003年 | 4篇 |
2002年 | 4篇 |
2001年 | 1篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1985年 | 1篇 |
1980年 | 1篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1964年 | 1篇 |
1961年 | 2篇 |
排序方式: 共有122条查询结果,搜索用时 0 毫秒
21.
H R Fischman J K Grigor J T Horman E Israel 《Journal of the American Veterinary Medical Association》1992,201(12):1883-1886
The epizootic of rabies in raccoons entered Maryland in 1981 and systematically moved through the state affecting raccoons in all counties except those of the lower Eastern Shore. A precoded surveillance form was provided to all county and city health departments and data were requested for each animal head submitted for testing for the year 1985. The disease persisted and, in 1987, all counties previously reporting rabies in raccoons also had documented cases in other species. The incidence of rabies in raccoons increased in late winter and peaked in March. Most human exposures occurred during daylight hours and in private yards. Agricultural areas were similarly affected by rabid animals. Analysis of vaccination status of animals exposed to rabid animals gave estimations of statewide vaccination rates for dogs (70%) and cats (28%). The danger of rabies in cats was emphasized by the large number of animals exposed by each rabid cat. The spillover of rabies in raccoons to other species persisted in all jurisdiction through 1992, with periodic upsurges of disease at 3- to 4-year intervals as the raccoon population is replenished. Rabies was not diagnosed in any human beings. 相似文献
22.
WR DuBois TM Prado JCH Ko RE Mandsager GL Morgan 《Veterinary anaesthesia and analgesia》2003,30(2):114-115
The anesthetic and cardiorespiratory effects of a low dose (LD, 0.4 mg kg?1 xylazine and 4 mg kg?1 ketamine) and a high dose (HD, 0.8 mg kg?1 xylazine and 8 mg kg?1 ketamine) of IM xylazine–ketamine combination were compared in a randomized cross‐over study using six castrated male llamas. Three llamas in each dosage group (LDT, HDT) were assigned to receive IM tolazoline (2 mg kg?1) after 30 minutes of recumbency. All IM injections were given in the semitendinosus or semimembranosus muscles. Pulse, respiratory rate, and indirect arterial blood pressure were recorded every 10 minutes, and hemoglobin oxygen saturation was recorded every 5 minutes during lateral recumbency. Samples for arterial blood gas analysis were collected 5 minutes following recumbency and every 30 minutes thereafter. Base‐to‐apex ECG was monitored continuously. Analgesia was evaluated every 5 minutes by both a 30 minutes skin pinch and a needle prick of the toe. Most llamas breathed room air throughout anesthesia. Two llamas that developed severe hypoxemia (SpO2 < 75%) received 5 minutes of nasal oxygen insufflation, but were maintained on room air for the rest of the anesthetic period. anova for repeated measures and Tukey's test were used to analyze cardiorespiratory data. Fischer's exact test was used to compare the ability of each to provide >30 minutes of lateral recumbency and analgesia. A p‐value < 0.05 was considered significant. Both dosages provided reasonably rapid induction following injection (LD: 10.8 ± 6.3 minutes; HD: 5.0 ± 1.1 minutes; p = 0.07). Duration of lateral recumbency and analgesia were 34.7 ± 6.7 and 27.3 ± 4.6 minutes, respectively, in the LDT llamas. None of the three remaining LD llamas remained in lateral recumbency for longer than 12 minutes. Duration of lateral recumbency and analgesia were 87.3 ± 18.5 and 67.7 ± 16.0 minutes, respectively, for the HD llamas that did not receive tolazoline. The HDT llamas were recumbent for a significantly shorter time (43.3 ± 0.6 minutes; p = 0.05). The ability to provide >30 minutes of recumbency and analgesia was better in the HD group (6/6) than in the LD group (2/6) (p = 0.03). No differences between dosages were seen in pulse rate, respiratory rate, or arterial pressures. No ECG abnormalities were seen. Transient hypoxemia was seen in the first 10 minutes of lateral recumbency in the HD group by both hemoglobin oxygen saturation (84 ± 9.5%) and by blood gas PaO2 (44.5 ± 5.8 mm Hg). It was concluded that the HD provided more consistent results than the LD, but induced transient hypoxemia. Tolazoline shortened the recovery time in llamas receiving the HD. 相似文献
23.
Rafael Arturo Torres-Fajardo Jorge Augusto Navarro-Alberto Javier Ventura-Cordero Pedro Geraldo González-Pech Carlos Alfredo Sandoval-Castro José Israel Chan-Pérez Juan Felipe de Jesús Torres-Acosta 《Strength and Conditioning Journal》2019,72(6):946-953
Feeding behavior is a multifactorial process with pivotal relevance for the maintenance and survival of ruminants. This study evaluated the effect of gastrointestinal nematodes (GIN), condensed tannin (CT) content of plants, and their possible interaction on the intake and selection of feed resources by Criollo goats in a heterogeneous vegetation. An 8-wk field experiment was conducted in the tropical deciduous forest (TDF) during the rainy season with adult Criollo goats (35.1 ± 6.7 kg body weight [BW]). Goats were assigned to four groups (n = 6): 1) MOX: suppressive treatment with moxidectin (Cydectin 0.4 mg/kg BW subcutaneous every 4 wk), 2) INF: with natural GIN infection, 3) MOX + PEG: treated with moxidectin and dosed with a CT-neutralizing agent (50 g of polyethylene glycol [PEG] diluted in 50 mL of water, per os), and 4) INF + PEG: with natural GIN infection and PEG dosage. Intake was measured using a direct observation method in a 2.2-ha TDF plot. Plant availability was obtained from 30 exclusion quadrants (2 × 2 m). Selection was estimated with the Cheeson index using the ratio of consumed plants and their availability by grouping plant species as shrubs and herbs (with high CT [> 10%], medium CT [> 3% to < 10%], or low CT [< 3%]), vines, and grasses. Neither GIN infection nor CT neutralization influenced intake or selection of feed resources. All groups showed high selection toward grass species (P < 0.001), which may represent a strategy to reduce intake of crude protein and CT from shrubs and herbs. In conclusion, GIN infection and CT neutralization do not influence intake or selection of goats with browsing experience in the TDF. Selection toward grass suggested a trade-off between nutrient harvest optimization and the health risk of GIN infective larvae consumption. Thus, it is necessary to revalorize the TDF as a sustainable feed resource for goats. 相似文献
24.
25.
Throughfall and stemflow measurements in a 60-year-old white oak stand (Quercus serrata Thunb.) were carried out during two periods totalling eleven months, from August to November 1993 and from May to November
1994, in order to clarify the rainfall partitioning of this forest. Troughs and spiral-type stemflow gauges connected to tipping
bucket-gauges were used for throughfall and stemflow measurements. Seventy-five storms were analyzed individually. Coefficients
of variation for throughfall and stemflow ranged between 5–25% and 20–70% respectively. Partitioning of net rainfall in throughfall
and stemflow represent 72% and 10% of the gross rainfall respectively. Multiple regression analyses were carried out to determine
the stemflow variability. In was determined that maximum rain intensity was highly correlated with stemflow and this variable
explained a further 5.5% of the stemflow variation. Estimates of averaged lag time and drainage after rain cease for stemflow
were 290 and 164 min, while estimates for throughfall were 60 and 104 min. respectively. The canopy saturation was estimated
from continuous storms and showed a value of 0.6 mm. The trunk storage capacity was estimated at a value of 0.2 mm. The interception
loss from the forest canopy was estimated in 18%. Interception loss was heighly correlated with rainfall characteristics such
as duration and intensity. 相似文献
26.
对杨树无性系:I-214(Populuseuramericanacv.I-214〕,健杨(P.euramericanaGuinircv.Robusta),中东杨(P.berolinensis)和群众杨(P.Popularis35-44)一年生盆栽插条苗进行干旱处理,研究了水分胁迫对四种苗木光合作用和叶绿素a荧光的影响.结果发现,苗木受旱后可变荧光提高20-50%,而恒定荧光未受水分胁迫的影响。鉴于光抑制是以可变荧光的降低为特征,因此得出光系统II光反应中心未受伤害的结论。对土壤干旱敏感的I-214和健杨受旱后净光合作用(Pn)剧烈下降,主要是由于非气孔因素的影响:即RUBP羧化酶(Rubisco)的活性降低.耐旱性强的群众杨和中东杨,Pn下降的幅度较小,气孔因素和非气孔因素都是影响光合作用的因子。通过干旱或ABA处理的叶片叶温升高,抑制了Rubisco的活性,也使叶绿素a荧光诱导曲线上的M峰消失,从而证实了M峰与光合作用暗反应的相关性。 相似文献
27.
28.
29.
30.