首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   23篇
  免费   3篇
林业   2篇
  1篇
综合类   3篇
农作物   3篇
水产渔业   1篇
畜牧兽医   11篇
园艺   2篇
植物保护   3篇
  2018年   2篇
  2016年   1篇
  2012年   3篇
  2011年   2篇
  2009年   1篇
  2006年   2篇
  2005年   1篇
  2004年   2篇
  2003年   3篇
  2000年   1篇
  1996年   1篇
  1995年   1篇
  1993年   1篇
  1991年   1篇
  1975年   1篇
  1967年   2篇
  1963年   1篇
排序方式: 共有26条查询结果,搜索用时 15 毫秒
1.
Foetal sex determination using polymerase chain reaction (PCR) in mammals is based on the amplification of gender‐specific foetal DNA sequences circulating in maternal blood. The bovine synepitheliochorial placenta does not allow a direct contact between the trophoblast and the maternal blood, resulting in difficult passage of foetal DNA and, consequently, its very small amounts in maternal bloodstream. Circulating cell‐free foetal DNA (ccffDNA) encompasses short nucleotide fragments (300–600 bp) in maternal circulation. The aim of this study was to assess this non‐invasive method in accurate prenatal sexing in early and late gestational periods in comparison with ultrasound diagnostics. As various DNA isolation and amplification methods were tested, their success in obtaining reliable results was evaluated. Two groups were tested, each consisting of 20 pregnant cows. Blood of a bull and a non‐pregnant heifer was the controls. Extraction of foetal DNA was accomplished by three different methods: using tubes with silicone membranes, a single‐tube extraction without silicone membranes and phenol–chloroform extraction. Following each extraction method, foetal DNA was amplified using PCR and real‐time PCR with both bAML and TSPY primers in a separate reaction. Positive results were obtained only after amplification of foetal DNA extracted with a single‐tube extraction kit. In comparison with ultrasound examination results and foetal gender recorded at birth, the sensitivity of the PCR test was 90% in Group I, but the technique failed to detect male foetuses in Group II. The real‐time PCR test sensitivity in Group I was 90% and in Group II 91.6%.  相似文献   
2.
For the first time soil solarization was investigated in Croatia both in the field and in the greenhouse in 1991, 1992, 1993 and 1994. For two months (July and August), the soil was mulched with transparent polyethylene (PE) sheets of 0.015 or 0.050mm thickness. Soil temperatures at depths of 5, 10 and 20cm were recorded daily. In order to assess nematode population densities, soil samples were analysed before mulching and at the end of the mulching treatment. The results of these experiments showed that soil solarization drastically reduced the population of plant-parasitic nematodes (Meloidogyne, Pratylenchus, Paratylenchus, Tylenchus, Tylenchorhynchus spp.) by about 97–100% at a depth of 10cm and 92–97% at a depth of 20cm in the field, while in the greenhouse, the population of plant-parasitic nematodes was reduced by about 89–100% at a depth of 10cm and 98–100% at a depth of 20cm.In the same experiments, the population of saprophytic nematodes in the field was reduced by about 86–90% at a depth of 10cm and 72–89% at a depth of 20cm. In the greenhouse, the population of saprophytic nematodes was reduced by about 87–97% at a depth of 10cm and 87–93% at a depth of 20cm. This data shows that soil solarization was less effective in the control of saprophytic nematodes, which is considered to be an advantage.  相似文献   
3.
Durch die Testimetrie-Methode und histologische Untersuchungen wurden saisonabhängige Veränderungen in der Hodengröβe und im Samenkanälchendurchmesser festgestellt. Im Winter waren die Hoden am kleinsten, ihre durchschnittliche Länge betrug 7,5.5 cm and das Volumen 144,38 cm3. In dieser Zeitperiode waren auch die Samenkanälchendurchmesser am kleinsten (187,4 ± 0,65 μ). Durch klinische Untersuchung konnte man eine weichelastische Konsistenz der Hoden feststellen. Im Frühling nehmen die Hodengröe und der Samenkanälchendurchmesser wieder zu und die Konssistenz wird festelastisch. Im Sommer haben die Hoden die gröβten Ausmaβe. Zu dieser Zeit sind sie im Durchschnitt 9,96 cm lang und das Volumen beträgt 369,36 cm3. Die Samenkanälchen haben in dieser Zeit den gröβten Durchmesser (M = 231,35 ± 1,225 ü) und ihre Variabilität ist gröβer als in den anderen Jahreszeiten. Die geringste Variabilitäl im Samenkanälchendurchmesser wurde im Herbst festgestellt, d. h. während der Paarungssaison. Die meisten Schafböcke, bei denim der Samenkanälchendurchmesser kleiner war (175,87 μ), gaben Sperma mit einer herabgesetzten Konzentration der Samenzellen (1 Milliarde in 1 ml Sperma). Bei Schafböcken mit norinaler Konzentration von Spermien (3–4 Milliarden Spermien in 1 ml) betrug der Durchmesser der Tubuli seminiferi 219,07 μ. Durch klinische Untersuchung wurden pathologische Veränderungen an den Hoden bei Schafböcken zumeist im Winter festgestellt. Geschlechtliche Beanspruchung in der vorausgegangenen Zeit and schlechtere Bedingungen bezüglich der Haltung and Fütterung der Tiere im Winter spielten allerdings in der Aetiologie der Hodenerkrankung eine wesentliche Rolle. Wir nehmen an, daβ auch die Saisoneinflüsse (Verkleinerung des Hodens and des Samenkanälchendurchmessers) zum Auftreten funktionaler Störungen der Hoden beitragen können.  相似文献   
4.
In the Balkan countries, where trichinellosis is a re-emerging zoonosis, it is of great importance to determine Trichinella infection prevalence among the major hosts, including horses. One method for monitoring prevalence is serological surveillance; however, the validity of serological methods in horses is not well understood. The dynamics of anti-Trichinella IgG production and circulating excretory/secretory (ES) antigens were investigated in three horses experimentally-infected with Trichinella spiralis. Horses were slaughtered at 32 week post infection (p.i.). Low worm burdens were found in all three animals. Anti-Trichinella IgG was detected up to 32 weeks p.i. by an indirect immunofluorescence assay (IFA) and by Western blot (Wb), but not by ELISA. The ELISA test detected antibodies for only a short period of time (up to 18 weeks p.i. using ES antigen or up to 20 weeks p.i. using tyvelose-BSA antigen). The presence of circulating muscle larvae ES antigen in sera of infected horses was observed by dot blot from the 4th week p.i. up to the 32nd week p.i.  相似文献   
5.
The heart is an organ especially sensitive to the sympathetic overstimulation and therefore to the influence of stressors and hypertension. The aim of the present study was to investigate the effect of two distinct types of stressors, acute immobilization (2 h) and chronic isolation stress (21 days), as well as their combined effect on the activity of monoamine oxidase (MAO), superoxide dismutase, catalase (CAT) and the ascorbic acid (AA) content in the heart of normotensive and spontaneously hypertensive rats (SHR). The results obtained show that in basal conditions heart MAO and CAT activity (p < 0.05), as well as AA concentration (p < 0.01) were higher in SHR than in normotensive ones. The acute immobilization significantly decreased heart MAO activity in both examined strains (p < 0.01). On the other hand, chronic isolation, separately or in combination with immobilization, did not affect this enzyme, in the heart of either hypertensive or normotensive rats, which was associated with the reduced antioxidative protection (p < 0.01, p < 0.05).  相似文献   
6.
Hydromorphone is an agonist opioid with potency approximately five times that of morphine and half that of oxymorphone. The purpose of this study was to compare hydromorphone with oxymorphone, with or without acepromazine, for sedation in dogs, and to measure plasma histamine before and after drug administration. Ten dogs received IM hydromorphone (H; 0.2 mg kg?1), oxymorphone (O; 0.1 mg kg?1), hydromorphone with acepromazine (H; 0.2 mg kg?1, A; 0.05 mg kg?1) or oxymorphone with acepromazine (O; 0.1 mg kg?1, A; 0.05 mg kg?1) in a randomized Latin‐square design. Sedation score, heart rate, respiratory rate, blood pressure, and SpO2 were recorded at baseline and every 5 minutes after drug administration up to 25 minutes. Plasma histamine was measured at baseline and at 25 minutes post‐drug administration. Data were analyzed with repeated measures anova . Mean ± SD body weight was 21.62 ± 1.54 kg. Mean ± SD age was 1.07 ± 0.19 years. Sedation score was significantly greater for OA after 5 minutes than O alone (4.1 ± 3.5 versus 1.9 ± 1.5) and for HA after 15 minutes than H alone (8.6 ± 2.9 versus 5.9 ± 2.5). There was no significant difference in sedation between H and O at any time point. There was no significant difference between groups at any time with respect to heart rate, respiratory rate, blood pressure or SpO2. Mean ± SD plasma histamine (nM ml?1) for all groups was 1.72 ± 2.69 at baseline and 1.13 ± 1.18 at 25 minutes. There was no significant change in plasma histamine concentration in any group. Hydromorphone is effective for sedation in dogs and does not cause measurable increase in histamine. Sedation with hydromorphone is enhanced by acepromazine.  相似文献   
7.
古浪引黄灌区土壤肥力平衡研究   总被引:1,自引:0,他引:1  
根据古浪县引黄灌区土壤调查结果、肥力现状以及作物种植结构和畜牧业发展等,对不同开发时期土壤肥力平衡进行了估算,提出了实现肥力平衡和提高土壤肥力的途径。  相似文献   
8.
Zusammenfassung Versuche über die Einwirkung des AetheroleumLavandulae auf das Auskeimen des weißen SenfesSinapis alba L.), sowie auf Längenwachstum und Entwicklung der Keimlinge, die aus den beeinflußten Samen hervorsprießen, werden am Lichte (500 Lux) und im Dunkeln durchgeführt.Das ätherische Öl wird im dampfförmigen Zustand (Atmosphäre) angewendet.Es wird festgestellt, daß die Atmosphären aller Konzentrationen ätherischer Öle stets hemmend auf das Keimlängewachstum wirken. Die stärkere Konzentration hemmt auch die Keimentwicklung, während das Auskeimen der Samen nur durch stärkere Konzentration am Lichte gehemmt wird.Das Auskeimen der unbeeinflußten und jener durch Atmosphären schwächerer Konzentrationen beeinflußten Samen wickelt sich im Dunkeln bei längerer Einwirkungsdauer ähnlich ab.Die hemmende Wirkung auf Auskeimen, Längenwachstum und Entwicklung der Keimlinge ist im Dunkeln wie im Lichte proportional der Konzentration der Atmosphäre.Die Atmosphäre stärkerer Konzentration hemmt gleichartig das Wurzel- und Hypokotyllängenwachstum.Das Keimlängenwachstum ist immer stärker gehemmt als der Keimungsprozess.
Summary In darkness, as in light examinations have been carried out on the effect of AetheroleumLavandulae on germination of White MustardSinapis alba L.) seeds, on the longitudinal growth and on the development of the germs sprouted from these seeds.The volatile oil was applied in evaporated form (atmosphere).It has been stated that the atmosphere of all volatile oil concentrations always acts inhibitory on growth of germs, that the higher concentration has inhibitory effects on their growth whilst the germination is inhibited only by a higher concentration and when germs in light are in question. In darkness as in atmosphere of lower concentrations of volatile oils there is a tendency of germination to equalise with the control.The inhibitory effect on germination as well as on longitudinal growth of germs in light, respectively in darkness is in proportion to the concentration of the atmosphere.Atmospheres of higher concentrations of volatile oils are of an equal inhibitory effect on the longitudinal growth of the radicle and of the hypocotyl.The longitudinal growth of germs is even more inhibited than the very process of germination.


mit 3 Fig.  相似文献   
9.
Zusammenfassung Im Rahmen der Untersuchungen phytodynamischer Eigenschaften ätherischer Öle sind Versuche über Wirkung von AetheroleumLavandulae, Menthae, Rosmarini, Salviae undThymi auf das Auskeimen eingeweichter und trockener Achänen des Salats(Lactuca sativa L.), sowie auf das Wachstum der Keimlinge dieser Achänen, durchgeführt worden. Ätherische Öle wurden in gelöstem oder dampfförmigem Zustand (Atmosphäre) angewendet.Festgestellt wurde, daß Atmosphäre oder Lösung schwächerer Konzentration der angewendeten ätherischen Öle fast nie inhibitorisch auf das Auskeimen der eingeweichten Achänen wirkt, aber, daß eine solche Wirkung auf trockene Achänen sehr ausgeprägt ist. Lösungen ätherischer Öle wirken schwächer als ihre Atmosphären. Atmosphären und Lösungen aller angewendeten ätherischen Öle zeigen weder eine Regelmäßigkeit in ihrer Wirkung auf das Auskeimen der Achänen, noch können Gruppen ätherischer Öle hervorgehoben werden, welche ständig ähnlich wirken.Das Wachstum der Keimlinge ist gehemmt durch die Wirkung der Lösung ätherischer Öle, bedeutender in Fällen, in denen das Auskeimen der Achänen schwächer ist. Das Längenwachstum der Keimlinge ist immer im größeren Maße als das Auskeimen gehemmt.Die inhibitorische Wirkung auf beide beobachteten Prozesse ist proportional der Konzentration der Atmosphäre oder Lösung.
Summary In the course of examinations on phytodynamic properties of volatile oils, assays with respect to the effect of Aetherol.Lavandulae, Menthae, Rosmarini, Salviae andThymi on germination of moistened and of dry lettuce achenes(Lactuca sativa L.), as well as on growth of the germ sprouted from these achenes have been carried out. The volatile oils were applied either in form of solution or as vapour (atmosphere).It has been stated that atmospheres as well as solutions of lower concentrations of the applied volatile oils hardly ever act inhibitory on germination of moistened achenes, whilst on dry achenes it proved to be rather considerable. The effect of solutions, on germination of achenes, is less raised than that of atmospheres of volatile oils.Neither do atmospheres as well as solutions of all the applied volatile oils constantly show a certain regularity in effect on germination of achenes nor could any volatile oil group of a similarly constant effect be stated.The longitudinal growth of germs is inhibited by the effect of volatile oil solutions, however, it is stronger when a slower germination of achenes is in question. The longitudinal growth is more inhibited than the process of germination.The inhibitory effect on both processes is proportional to the concentration of the atmosphere or of the solution.

Zakljuak U okviru ispitivanja fitodinamskog svojstva eterskih ulja vreni su pokusi djelovanja Aetheroleum Lavandulae, Menthae, Rosmarini, Salviae i Thymi na klijanje kvaenih i suhih roki salate(Lactuca sativa L.), te na rast klica razvitih iz tih roki. Eterska ulja su primijenjena u obliku otopine ili hlapljevine (atmosfere).Utvrdjeno je da atmosfere ili otopine slabijih koncentracija eterskih ulja gotovo nikad ne djeluju inhibitorno na isklijavanje kvaenih roki, dok je takvodjelovanje na suhe roke vrlo znatno. Na isklijavanje slabije djeluju otopine od atmosfera eterskih ulja. Atmosfere i otopine svih primijenjenih eterskih ulja niti stalno pokazuju neku pravilnost u djelovanju na isklijavanje roki niti se mogu uturditigrupe eterskih ulja koje bi se stalno odlikovale slinim djelovanjem.Duinski rast klica je koen djelovanjem otopina eterskih ulja, a znatniji je u sluojevima u kojima je isklijavanje roki brojnije. Duinski rast sam je u veoj mjeri koen od isklijavanja.Inhibitorno je djelovanje u oba promatrana procesa proporcionalno s koncentracijom atmosfere ili otopine.
  相似文献   
10.
Stem cuttings with homogenous diameter of Populus x euramericana (clone I-214) and Salix fragilis L. were grown in growth chamber in water culture method. After 45?days, the plants were treated with 10?7 and 10?5?M cadmium (Cd). As these species have different phytoextraction potentials, there is a need to analyze the level of Cd uptake, its translocation into aboveground organs, and changes in leaf structure. We analyzed micromorphological leaf characteristics: a fresh mass of the root, stem, and leaf, as well as a Cd concentration within them. Besides, we compared 23 micromorphological leaf blade quantitative traits of poplar and willow and monitored the structural changes induced by the intoxication of stem cuttings. Percent of Cd accumulation and translocation in plant organs varied between species. It depended on the level of Cd applied. When compared to the poplar clone, S. fragilis had a smaller leaf area and epidermal cells, thicker palisade tissue, smaller lumen of main vein vessels, and a higher percentage of main vein xylem. S. fragilis had more distinctive xeromorphic characteristics in the lamina structure. Increased concentrations of Cd led to significant structural changes, mainly in the main vein. When searching for valid parameters in assessing plant to be utilized in phytoremediation, it is necessary to take into consideration the interrelation of a large number of micromorphological parameters together with physiological and biochemical characteristics.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号