全文获取类型
收费全文 | 629篇 |
免费 | 58篇 |
专业分类
林业 | 12篇 |
农学 | 4篇 |
基础科学 | 1篇 |
79篇 | |
综合类 | 173篇 |
农作物 | 14篇 |
水产渔业 | 14篇 |
畜牧兽医 | 354篇 |
园艺 | 2篇 |
植物保护 | 34篇 |
出版年
2020年 | 9篇 |
2019年 | 8篇 |
2018年 | 16篇 |
2017年 | 20篇 |
2016年 | 8篇 |
2015年 | 14篇 |
2014年 | 19篇 |
2013年 | 24篇 |
2012年 | 18篇 |
2011年 | 30篇 |
2010年 | 22篇 |
2009年 | 14篇 |
2008年 | 17篇 |
2007年 | 18篇 |
2006年 | 24篇 |
2005年 | 15篇 |
2004年 | 17篇 |
2003年 | 18篇 |
2002年 | 16篇 |
2001年 | 6篇 |
2000年 | 12篇 |
1999年 | 12篇 |
1998年 | 7篇 |
1997年 | 11篇 |
1996年 | 6篇 |
1993年 | 7篇 |
1992年 | 8篇 |
1991年 | 8篇 |
1990年 | 12篇 |
1988年 | 11篇 |
1987年 | 11篇 |
1986年 | 10篇 |
1985年 | 10篇 |
1984年 | 7篇 |
1983年 | 7篇 |
1982年 | 8篇 |
1981年 | 7篇 |
1978年 | 8篇 |
1976年 | 5篇 |
1973年 | 6篇 |
1972年 | 9篇 |
1970年 | 6篇 |
1969年 | 7篇 |
1968年 | 6篇 |
1920年 | 5篇 |
1918年 | 5篇 |
1915年 | 8篇 |
1911年 | 4篇 |
1909年 | 5篇 |
1908年 | 5篇 |
排序方式: 共有687条查询结果,搜索用时 312 毫秒
11.
AE Jackson 《Australian veterinary journal》2011,89(6):197-198
Computer model predictions and field observations of anthelmintic resistance in sheep · Dangers of off‐label use of barium selenate · Elbow luxation in dogs and cats · Prognosis of joint infections in adult horses · Omentalisation for mediastinal abscess in a dog · Adenoviruses in lizards 相似文献
12.
Robert C Cole Federica Morandi James Avenell Gregory B Daniel 《Veterinary radiology & ultrasound》2005,46(2):146-152
The purpose of this study was to (1) establish a technique for ultrasound-guided trans-splenic portal scintigraphy (TSPS) using 99mTcO4(-), (2) evaluate portal vein morphology, (3) compare the radiation exposures for TSPS vs. per-rectal portal scintigraphy (PRPS), and (4) compare the quality of numerical data from the TSPS vs. PRPS. Eight juvenile dogs underwent PRPS and TSPS (minimum of 48h between studies) after initial screening tests. PRPS was done according to established protocol using 425 +/- 36MBq (mean +/- SD) of 99mTcO4(-). TSPS was done with the dogs in right lateral recumbency over the gamma camera. 99mTcO4(-) (57 +/- 13.9 MBq) was injected into the spleen 1-2s following initiation of the dynamic acquisition. The frame rate was 4 frames/s for 5 min. There was significantly lower radioactivity of 99mTcO4(-) given and significantly higher total counts recorded in the liver and heart during the TSPS compared with PRPS. The total counts for the TSPS and PRPS were 7120 +/- 4386 and 830 +/- 523, respectively. Percent absorption from the spleen was 52.5 +/- 19.1% compared with 9.2 +/- 5.7% for the colon. Calculated transit time for the TSPS studies was 7 +/- 2.3s. In TSPS studies, the splenic and portal veins were clearly identified. Radiation exposure levels of the dogs were significantly lower following TSPS than after PRPS. TSPS appears superior to PRPS as a method to image the portal venous system representing a valid alternative diagnostic test for animals with suspected portosystemic shunts. 相似文献
13.
Expression of metabolism-inhibition antibodies against Mycoplasma arthritidis in rats 总被引:1,自引:0,他引:1
Shared antigens between Mycoplasma arthritidis and rat tissues may be responsible for the lack of metabolism-inhibition (MI) and other neutralizing antibodies in rats with M arthritidis-induced arthritis. We were not able to confirm such antigens or to detect cross-reacting antigens between M arthritidis and rat lymphocytes, thymocytes, and muscle tissue. Antisera of rabbit origin to rat lymphocytes, thymocytes, and skeletal muscle reacted by ELISA with M arthritidis only when the mycoplasmal antigens were prepared from organisms grown in medium containing horse serum. Such activity could be completely absorbed by horse serum. These antisera to rat tissues also failed to react by radioimmunoprecipitation with M arthritidis surface antigens. In addition, antibody activity against homologous antigens could not be absorbed by M arthritidis. Similarly, antisera of rabbit origin against M arthritidis failed to react by ELISA specifically with rat lymphocytes, thymocytes, and skeletal muscle or to react by radioimmunoprecipitation with 125I-labeled rat lymphocyte antigens. These rat tissues could not specifically absorb antibodies against M arthritidis from antisera of rabbit origin. These findings suggest that the lack of MI antibodies in rats probably can not be explained by rat tissue antigens that cross-react with M arthritidis MI antigens. Finally, antisera of rat origin against M arthritidis and other rat tissue components failed to block rabbit MI activity against M arthritidis, thus arguing against steric hindrance as a means of preventing recognition of MI antigens. 相似文献
14.
15.
16.
Relationship of vulvar swelling to estrus in mink 总被引:1,自引:0,他引:1
17.
Cole LK Kwochka KW Kowalski JJ Hillier A Hoshaw-Woodard SL 《Veterinary therapeutics : research in applied veterinary medicine》2003,4(1):12-23
Thirty-one ears (16 dogs) with otitis externa originating from bacterial or yeast infections were enrolled in a study to evaluate the in vivo efficacy of an ear cleanser containing 2.5% lactic acid and 0.1% salicylic acid for the treatment of infectious otitis externa. The affected ears were treated with the ear cleanser twice daily for 2 weeks and evaluated after 1 and 2 weeks of treatment. The ear cleanser was effective in resolution of infection in 67.7% of the ears, and clinical signs of infectious otitis externa were significantly reduced within 2 weeks. 相似文献
18.
ABSTRACT Inflorescences of field-grown grapevines (Vitis vinifera L. cv. Gamay) were inoculated with a Botrytis cinerea conidia suspension or dried conidia at different stages during bloom in moist weather. Approximately 10% of the conidia germinated within 72 h, resulting in two to three times more latent infections than uninoculated controls in pea-size (7 mm in diameter) berries. In surface-sterilized pea-size berries, latent B. cinerea was present predominantly in the receptacle area. After veraison, latent B. cinerea also was found in the style and, in mature berries, latent colonies were distributed throughout the pulp. Inoculation at full bloom led to the highest disease severity (66%) at harvest, compared with 38% in controls. Stilbene stress metabolites in the flowers were measured by high-performance liquid chromatography. Resveratrol accumulated mainly after pre-bloom and full-bloom inoculation, but did not prevent infection. Piceid levels did not change following inoculation, while epsilon-viniferin was found in necrotic tissues only, and pterostilbene and alphaviniferin were not detected at all. B. cinerea conidia suspensions also were applied to various locations on flowers of pot-grown cvs. Pinot Noir and Chardonnay. Inoculation of the receptacle area, but not that of the stigma and ovary, resulted in latent infections. Stilbene synthesis was similar to the field results, with resveratrol accumulating mainly in the calyptra and receptacle area. Constitutive soluble phenolic compounds (mainly derivatives of quercetin and hydroxy-cinnamic acid) were present at high concentrations in the calyptra but at low levels in the receptacle area. These experiments confirmed bloom as a critical time for B. cinerea infection in grapes and suggest that the most likely site of infection is the receptacle area or cap scar exposed at anthesis. Stilbenes may have a limited role in inhibition of flower infection and latency in susceptible grape cultivars, and epsilon-viniferin may be a by-product rather than a deterrent of infection. 相似文献
19.
Starai VJ Celic I Cole RN Boeke JD Escalante-Semerena JC 《Science (New York, N.Y.)》2002,298(5602):2390-2392
Acetyl-coenzyme A (CoA) synthetase (Acs) is an enzyme central to metabolism in prokaryotes and eukaryotes. Acs synthesizes acetyl CoA from acetate, adenosine triphosphate, and CoA through an acetyl-adenosine monophosphate (AMP) intermediate. Immunoblotting and mass spectrometry analysis showed that Salmonella enterica Acs enzyme activity is posttranslationally regulated by acetylation of lysine-609. Acetylation blocks synthesis of the adenylate intermediate but does not affect the thioester-forming activity of the enzyme. Activation of the acetylated enzyme requires the nicotinamide adenine dinucleotide-dependent protein deacetylase activity of the CobB Sir2 protein from S. enterica. We propose that acetylation modulates the activity of all the AMP-forming family of enzymes, including nonribosomal peptide synthetases, luciferase, and aryl- and acyl-CoA synthetases. These findings extend our knowledge of the roles of Sir2 proteins in gene silencing, chromosome stability, and cell aging and imply that lysine acetylation is a common regulatory mechanism in eukaryotes and prokaryotes. 相似文献
20.