全文获取类型
收费全文 | 1270篇 |
免费 | 10篇 |
国内免费 | 6篇 |
专业分类
林业 | 24篇 |
农学 | 20篇 |
基础科学 | 1篇 |
138篇 | |
综合类 | 499篇 |
农作物 | 33篇 |
水产渔业 | 12篇 |
畜牧兽医 | 527篇 |
园艺 | 1篇 |
植物保护 | 31篇 |
出版年
2019年 | 4篇 |
2012年 | 70篇 |
2011年 | 111篇 |
2010年 | 20篇 |
2009年 | 13篇 |
2008年 | 80篇 |
2007年 | 95篇 |
2006年 | 75篇 |
2005年 | 75篇 |
2004年 | 75篇 |
2003年 | 90篇 |
2002年 | 64篇 |
2001年 | 57篇 |
2000年 | 69篇 |
1999年 | 32篇 |
1997年 | 4篇 |
1995年 | 7篇 |
1994年 | 16篇 |
1993年 | 10篇 |
1992年 | 15篇 |
1991年 | 15篇 |
1990年 | 18篇 |
1989年 | 7篇 |
1986年 | 5篇 |
1981年 | 7篇 |
1979年 | 4篇 |
1971年 | 4篇 |
1969年 | 4篇 |
1967年 | 5篇 |
1966年 | 6篇 |
1963年 | 4篇 |
1960年 | 4篇 |
1958年 | 6篇 |
1957年 | 5篇 |
1956年 | 11篇 |
1954年 | 6篇 |
1953年 | 4篇 |
1948年 | 5篇 |
1947年 | 4篇 |
1946年 | 4篇 |
1945年 | 5篇 |
1944年 | 5篇 |
1942年 | 4篇 |
1934年 | 4篇 |
1928年 | 4篇 |
1920年 | 5篇 |
1900年 | 4篇 |
1898年 | 3篇 |
1893年 | 8篇 |
1892年 | 7篇 |
排序方式: 共有1286条查询结果,搜索用时 226 毫秒
1.
van Miert AS 《The Veterinary quarterly》1985,7(3):200-216
Summary Acute febrile diseases are characterized by specific and non-specific symptoms. The non-specific responses are presented under the headings: fever, inflammation and pain, experimental models for investigating febrile reactions, haematologic changes, blood biochemical changes, cardiovascular effects, changes in gastric function, and the effects of fever upon pharmacokinetics of drugs. It was the purpose of this review to describe present concepts of thermoregulation and fever, the associated reactions produced by bacterial pyrogens and the mechanisms of these reactions. The available data illustrate, that many questions have not yet been clearly answered. However, the entire field of research involving endogenous substances, such as interleukin-1, is now moving ahead with great speed. Furthermore, there is some evidence which suggests that fever and the associated lower plasma zinc and iron levels act together as a co-ordinated non-specific host defence mechanism. Since experimental fever has a distinct effect upon the pharmacokinetics of drugs, more attention should be given to this aspect. 相似文献
2.
3.
4.
5.
Baranov AS Graml R Pirchner F Schmid DO 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》1993,110(1-6):385-392
SUMMARY: Muzzle dermatoglyphics - n. ridges, granula and vibrissae - were analysed in various breeds. Differences among these in most traits were significant. Herd effects accounted for about 1/10 of the variance and heritability, estimated by combining sib, halfsib and dam-daughter correlations corrected for herd differences was above 50% for ridges and vibrissae and about 30% for granula. Genetic correlations between ridge counts and n. vibrissae in different nose fields, respectively, were high as they were between the former and n. granula but they were negative or very low between vibrissae and the other two traits. Asymmetry among the counts in the two muzzle sides was significant for nearly all traits, Heritabilities were low, around 10 to 20%, and the crossbreds had less asymmetry than their parental breeds. The correlations among asymmetry measures were low. ZUSAMMENFASSUNG: Rassenunterschiede und genetische Variabilit?t von Flotzmaulmustern Flotzmaulmerkmale - Zahl von Leisten, Warzen und Haaren - wurden in verschiedenen Rassen untersucht. Unterschiede zwischen diesen waren für alle Merkmale signifikant. Herdeneinflüsse verursachten etwa 1/10 der Varianz und Heritabilit?tswerte, gesch?tzt aus Korrelationen zwischen Zwillingen, Halbgeschwistern und T?chter-Müttern, korrigien für Herdeneinflüsse, variierten zwischen 36 und mehr als 50%. Genetische Korrelationen zwischen Leistenzahl und Zahl von Haaren in verschiedenen Flotzmaulfeldern waren hoch, ebenso wie die zwischen ersteren und Zahl von Warzen, aber sie waren negativ oder sehr gering zwischen Haaren und den andern beiden Merkmalen. Asymmetrie zwischen Zahlen in beiden Flotzmaulh?lften war signifikant für fast alle Merkmale. Heritabilit?tswerte waren niedrig, etwa 10-20% und Kreuzungstiere zeigten weniger Asymmetrie als ihre Herkunftsrassen. Die Korrelationen zwischen Asymmetriema?en waren niedrig. 相似文献
6.
For years, crop science has been balkanized, with specialists in rice, corn, and soybeans, for example, working on their own commodities and attending their own meetings. But at the First International Crop Science Congress, held in July in Ames, Iowa-an 8-day event 3 years in the making-the discipline displayed a newfound hybrid vigor. More than 1000 researchers of various persuasions, including plant molecular biology, classical plant breeding, agronomy, and soil science, representing 85 countries, shared their expertise in basic and applied studies. Here are a couple of proposals for expanding world food production and another that shows the diverse roles crops can play. 相似文献
7.
8.
9.
Antúnez K Piccini C Castro-Sowinski S Rosado AS Seldin L Zunino P 《Veterinary microbiology》2007,124(1-2):178-183
Paenibacillus larvae is the causative agent of American Foulbrood (AFB), a severe disease of honeybees (Apis melifera). The aim of this work was to develop a strategy for the subtyping and the epidemiological analysis of P. larvae. Phenotypic characterisation, susceptibility to several antibiotics, electrophoresis of whole bacterial proteins, rep-PCR, ribotyping and DGGE were assessed using a collection of P. larvae isolates from different Uruguayan and Argentinean locations. Results indicated that there are two P. larvae genotypes circulating in Uruguay ERIC I-BOX A (worldwide distributed) and ERIC I-BOX C (exclusively detected in Argentina until this study). These results suggest that P. larvae isolates had moved between Argentina and Uruguay, probably through the Uruguay River. Patterns of whole bacterial proteins, DGGE and ribotyping did not improve the P. larvae intraspecific discrimination. Antibiotic susceptibility assays showed that 100% isolates were OTC-sensitive and 22% (belonging to ERIC I-BOX A group) were sulfisoxazole-resistant. This work may contribute to the elucidation of basic aspects related to the epidemiology of AFB in Uruguay and in the region. 相似文献
10.
Mohammad FK Alias AS Faris GA Al-Baggou BKh 《Journal of veterinary medicine. A, Physiology, pathology, clinical medicine》2007,54(3):140-143
A modified electrometric cholinesterase method has been described for use in ruminants exposed to organophosphate insecticides. The method was used to measure cholinesterase activities in the plasma and erythrocytes of sheep, goats and cattle treated with organophosphate insecticides under field conditions. The animals were treated topically to control ectoparasites with malathion (0.05%) or diazinon (0.06%). The treated animals did not suffer from adverse effects related to cholinesterase inhibition. However, 2 h after treatments, plasma and erythrocyte cholinesterase activities significantly decreased in sheep by 20% and 39% and in goats by 18% and 30%, respectively, when compared with respective untreated control values. Diazinon did not significantly affect plasma and erythrocyte cholinesterase activities in the cattle. The results suggest that the described electrometric method could be efficiently used for detecting cholinesterase inhibition in ruminants exposed to organophosphate insecticides. 相似文献