全文获取类型
收费全文 | 165篇 |
免费 | 7篇 |
专业分类
林业 | 1篇 |
农学 | 36篇 |
基础科学 | 2篇 |
6篇 | |
综合类 | 23篇 |
农作物 | 4篇 |
水产渔业 | 2篇 |
畜牧兽医 | 83篇 |
植物保护 | 15篇 |
出版年
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 3篇 |
2017年 | 2篇 |
2015年 | 2篇 |
2014年 | 5篇 |
2013年 | 8篇 |
2011年 | 5篇 |
2010年 | 4篇 |
2009年 | 4篇 |
2008年 | 3篇 |
2006年 | 2篇 |
2005年 | 5篇 |
2004年 | 2篇 |
2003年 | 3篇 |
2002年 | 3篇 |
2001年 | 2篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 6篇 |
1997年 | 10篇 |
1996年 | 10篇 |
1995年 | 3篇 |
1994年 | 6篇 |
1993年 | 5篇 |
1992年 | 4篇 |
1991年 | 8篇 |
1990年 | 2篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1985年 | 2篇 |
1983年 | 1篇 |
1975年 | 1篇 |
1970年 | 1篇 |
1965年 | 1篇 |
1963年 | 1篇 |
1962年 | 3篇 |
1961年 | 2篇 |
1960年 | 2篇 |
1959年 | 5篇 |
1958年 | 3篇 |
1957年 | 2篇 |
1956年 | 3篇 |
1955年 | 3篇 |
1954年 | 3篇 |
1953年 | 3篇 |
1948年 | 1篇 |
1947年 | 1篇 |
1926年 | 1篇 |
排序方式: 共有172条查询结果,搜索用时 15 毫秒
71.
Effects of respacing on young Sitka spruce crops 总被引:1,自引:0,他引:1
72.
Neodymium (Nd) isotopic data show consistent patterns in the sources of sedimentary rocks in North America at a continental scale. Between 600 and 450 million years ago (Ma), ancient continental shield sources dominated. Around 450 Ma, detritus from the Caledonian-Appalachian mountains overwhelmed sediment from all older sources, and is documented over large areas of the southern, western, and northern margins of North America. This material continued to dominate the sediment supply until about 150 Ma, probably due to cannibalistic recycling of sedimentary rocks formed earlier. Around 150 Ma, the rising western Cordillera delivered new and different detritus to the sedimentary system. 相似文献
73.
Constance E. De Haan DVM Susan L. Kraft DVM PhD Patrick R. Gavin DVM PhD Lyle R. Wendling MD Merle L. Griebenow 《Veterinary radiology & ultrasound》1994,35(2):83-86
Detecting canine brain lesions on computed tomography (CT) or magnetic resonance (MR) scans can be difficult if the lesions do not enhance well following administration of intravenous contrast material. Changes in the shape and position of the ventricular system can be important in the diagnosis of such lesions. Normal variation within the canine ventricular system has not been documented. MR scans from 62 normal Labrador retriever type dogs were evaluated. Five dogs had symmetric enlargement of the ventricles, while nineteen dogs had mild to severe ventricular asymmetry. The incidence of asymmetry in normal dogs must be considered when using ventricular configuration as an indication of central nervous system abnormality. 相似文献
74.
Frequencies of sister chromatid exchanges (SCEs) in cultured blood lymphocytes are rather lower than higher in calves with hereditary zinc deficiency (lethal trait A 46) than in healthy, normal cows. 相似文献
75.
76.
J J de Haan C B Andreasen 《Journal of the American Veterinary Medical Association》1992,200(7):943-946
Calcium pyrophosphate dihydrate (Ca2P2O7.2H2O) crystal-associated arthropathy (pseudogout) was diagnosed in a dog. Clinical signs included non-weightbearing lameness, signs of pain on joint manipulation, and high rectal temperature. Arthrocentesis of carpal joints revealed extra- and intracellular crystals containing calcium. The suspected cause was polyarthritis secondary to chronic Ehrlichia infection. Results of joint tap performed after resolution of the clinical signs were negative for calcium pyrophosphate dihydrate crystals. 相似文献
77.
Animal welfare is expected to increase in importance as a political and marketing issue. There is a vigorous debate about what, besides the absence of physical pain, is necessary for acceptable animal welfare. This paper focuses on the present state of animal welfare policy at the national level. 相似文献
78.
Nahas SM Hondt HA Othman OS Bosma AA Haan NA 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》1993,110(1-6):182-185
SUMMARY: To identify the river buffalo chromosome carrying the genes coding for GAPD, TPI1, and LDHB, karyotypic examination was carried out on 14 buffalo-hamster hybrid clones previously tested for presence of this syntenic group. In cattle, this group (U3) has been assigned to chromosome 5, which is assumed to be homologous to the long arm of buffalo chromosome 4. Chromosome 4 was present in all five clones expressing the three enzymes, and absent in all seven negative clones, indicating that in the buffalo GAPD, TPI1, and LDHB are located on chromosome 4. One clone, expressing GAPD and TPI1, but not LDHB, was found to carry a translocation between hamster marker chromosome M(2) and buffalo 4q1 → 4qter. In another clone, expressing LDHB, but not GAPD and TPI1, chromosome 4 was absent, while a very small, unidentifiable acrocentric was present. These observations suggest that LDHB is located in the proximal part of 4q1, and that GAPD and TPI1 are located more distally, in 4q1 → 4q2. ZUSAMMENFASSUNG: Lokalisierung von Genen auf Chromosom 4 des Flu?büffels durch Büffel-Hamster-Hybridzellen Zur Identifikation von Flu?büffelchromosomen mit Genen für GAPD, TPI1 und LDHB wurden Karyotypenbestimmungen an 14 Büffel-Hamster-Hybridklonen durchgeführt, die vorher auf Anwesenheit der betreffenden synthenischen Gruppen geprüft worden waren. Bei Rindern wird diese Gruppe (U3) dem Chromosom 5 zugeordnet, welches als homolog mit dem langen Arm des Büffelchromosoms 4 betrachtet wird. Chromosom 4 war in allen fünf Klonen, die die drei Enzyme exprimiert haben, vorhanden und fehlte in allen sieben negativen klonen, so da? angenommen werden kann, da? sich bei Büffeln GAPD, TPI1 und LDHB auf Chromosom 4 befinden. Bei einem Klon, der GAPD und TPI1, aber nicht LDHB zeigte, wurde eine Translokation zwischen dem Hamstermarkerchromosom M2 und Büffel 4q1 → 4qter gefunden. Im einem anderen Klon, der LDHB, nicht aber GAPD und TPI1 zeigte, war Chromosom 4 nicht vorhanden, wohl aber ein sehr kleines, nicht identifizierbares akrozen-trisches Chromosom. Diese Beobachtungen weisen darauf hin, da? sich LDHB im proximalen Teil von 4q1 befindet und GAPD und TPI1 vertu distal in 4q1 → 4q2 lokalisiert sind. 相似文献
79.
80.
RA McKenzie AM Carmichael ML Schibrowski SA Duigan JA Gibson JD Taylor 《Australian veterinary journal》2009,87(1-2):27-32
Polioencephalomalacia was diagnosed histologically in cattle from two herds on the Darling Downs, Queensland, during July–August 2007. In the first incident, 8 of 20 18-month-old Aberdeen Angus steers died while grazing pastures comprising 60% Sisymbrium irio (London rocket) and 40% Capsella bursapastoris (shepherd's purse). In the second incident, 2 of 150 mixed-breed adult cattle died, and another was successfully treated with thiamine, while grazing a pasture comprising almost 100% Raphanus raphanistrum (wild radish). Affected cattle were either found dead or comatose or were seen apparently blind and head-pressing in some cases. For both incidents, plant and water assays were used to calculate the total dietary sulfur content in dry matter as 0.62% and 1.01% respectively, both exceeding the recommended 0.5% for cattle eating more than 40% forage. Blood and tissue assays for lead were negative in both cases. No access to thiaminase, concentrated sodium ion or extrinsic hydrogen sulfide sources were identified in either incident. Below-median late summer and autumn rainfall followed by above-median unseasonal winter rainfall promoted weed growth at the expense of wholesome pasture species before these incidents. 相似文献