全文获取类型
收费全文 | 343篇 |
免费 | 30篇 |
国内免费 | 1篇 |
专业分类
林业 | 9篇 |
农学 | 16篇 |
30篇 | |
综合类 | 15篇 |
农作物 | 13篇 |
水产渔业 | 6篇 |
畜牧兽医 | 266篇 |
园艺 | 2篇 |
植物保护 | 17篇 |
出版年
2022年 | 2篇 |
2020年 | 8篇 |
2019年 | 4篇 |
2018年 | 7篇 |
2017年 | 4篇 |
2016年 | 9篇 |
2015年 | 8篇 |
2014年 | 5篇 |
2013年 | 22篇 |
2012年 | 12篇 |
2011年 | 11篇 |
2010年 | 9篇 |
2009年 | 18篇 |
2008年 | 16篇 |
2007年 | 19篇 |
2006年 | 13篇 |
2005年 | 16篇 |
2004年 | 12篇 |
2003年 | 20篇 |
2002年 | 12篇 |
2001年 | 10篇 |
2000年 | 8篇 |
1999年 | 7篇 |
1998年 | 9篇 |
1997年 | 7篇 |
1995年 | 6篇 |
1994年 | 2篇 |
1992年 | 5篇 |
1991年 | 7篇 |
1990年 | 11篇 |
1989年 | 14篇 |
1988年 | 4篇 |
1987年 | 6篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1978年 | 3篇 |
1977年 | 5篇 |
1975年 | 4篇 |
1974年 | 3篇 |
1973年 | 6篇 |
1972年 | 3篇 |
1967年 | 1篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1944年 | 1篇 |
1937年 | 1篇 |
排序方式: 共有374条查询结果,搜索用时 375 毫秒
1.
A series of 10 farm trials was conducted in which the lambing performance of ewes immunised against polyandroalbumin was compared with that of untreated ewes in the same flock. The trials show that polyandroalbumin treatment is a reliable method of increasing lambing and tailing percentages in New Zealand flocks. An average of 39 extra lambs born per 100 ewes tupped was achieved on farms where ewes were given two treatments about four weeks apart and rams were introduced 18-26 days after the second dose. On farms where rams were introduced less than 12 days after this booster injection an average of 19 extra lambs born per 100 ewes tupped resulted. On farms where rams were introduced at 18-26 days post booster injection an average of 35 extra lambs were tailed for every 100 ewes tupped. The response for immunization increased in direct relation to the liveweight of the ewes at tupping. 相似文献
2.
3.
Experimental Neospora Caninum Infection in Pregnant Dairy Heifers Raises Concentrations of Pregnancy‐Associated Glycoproteins 1 and 2 in Foetal Fluids
下载免费PDF全文
![点击此处可从《Reproduction in domestic animals》网站下载免费的PDF全文](/ch/ext_images/free.gif)
R Mur‐Novales F López‐Gatius B Serrano‐Pérez I García‐Ispierto L Darwich O Cabezón NM de Sousa JF Beckers S Almería 《Reproduction in domestic animals》2016,51(2):282-286
Plasma concentrations of PAG‐1 are used for pregnancy diagnosis and as a marker of placental/foetal well‐being, while those of PAG‐2 may be an indicator of abortion risk in Neospora caninum‐infected cows. Studies have shown that N. caninum infection modifies PAG‐1 and PAG‐2 patterns in maternal blood plasma. However, no prior work has examined the effects of N. caninum infection on concentrations of PAGs in foetal fluids. In this study, PAG‐1, PAG‐2 and pH levels were determined in the amniotic and allantoic fluids of foetuses collected at 152 days of gestation from control uninfected dams and from dams experimentally infected with N. caninum on Day 110 of gestation. Foetal fluids from infected foetuses had significantly higher PAG‐2 concentrations (p = 0.026) and pH values (p = 0.02) than fluids from non‐infected foetuses. In infected foetuses, significantly higher concentrations of PAG‐1 (p < 0.001) and PAG‐2 (p < 0.001) were detected in fluid samples showing antibodies against N. caninum than those without antibodies. Moreover, pH values were significantly higher (p = 0.011) in foetal fluid samples with antibodies than in samples from non‐infected foetuses. In conclusion, this is the first report on the effect of N. caninum infection on PAG levels in foetal fluids. Our results indicate that following the experimental infection of dams with N. caninum on Day 110 of gestation, foetal fluids collected from the infected foetuses of these dams featured higher PAG‐1 and PAG‐2 levels and pH values than fluids from non‐infected controls, provided that the samples tested showed the presence of antibodies. The clinical implications of these findings are that following infection with N. caninum, most cows will experience some level of placental damage and that this injury correlates with foetal fluid PAG levels and pH. 相似文献
4.
Young adult sheep were dosed with extracts of Narthecium ossifragum plants by the oral or parenteral routes and the resulting nephrotoxicity was assessed from the increases in the concentrations of creatinine and urea in the serum. Following single intraruminal or intraperitoneal doses of extracts derived from 30 g N. ossifragum (wet weight) per kg live weight (kg lw), serum creatinine concentrations increased from about 100 mol/L to between 260 and 510 mol/L. The serum urea concentrations increased from about 5–8 mmol/L to between 11 and 66 mmol/L in individual sheep. Daily intraruminal administration of 5–30 g/kg lw to three sheep over a 10- or 15-day period increased creatinine concentrations from 100 mol/L to 300–760 mol/L, and urea concentrations from 5–8 mmol/L to 35 mmol/L. A single intraperitoneal challenge dose of 30 g/kg lw, delivered 7 or 12 days after the final intraruminal dose, did not lead to increased serum creatinine or urea concentrations, indicating that oral treatment had apparently resulted in an increased tolerance to the nephrotoxic principle(s) in N. ossifragum. 相似文献
5.
A Répási JF Beckers J Sulon A Karen J Reiczigel O Szenci 《Reproduction in domestic animals》2005,40(5):436-442
Lactating dairy cows (n = 72) with a mature corpus luteum (CL) (diameter of > or = 17 mm) determined by ultrasonography and having a follicle with a diameter of > or = 10 mm were randomly assigned to four groups. Cows were treated with cloprostenol i.m. once or twice, or with dinoprost i.m. once or twice with an 8-h interval. The ovaries of each cow were scanned daily by transrectal ultrasonography to measure the changes in the areas of CL and the largest follicle and to determine the occurrence of ovulation. Oestrus was verified twice daily. In addition, blood sample was withdrawn from each cow daily for measuring progesterone (P4) concentrations. Significant decreases in the percentage changes relative to areas of CL and P4 concentrations or increases in the percentage changes in the area of the largest follicle on day 0 were detected in each group during the experiment. However, the type of the drug and the number of the treatments had no significant effect on those parameters. Cows ovulated with or without showing oestrus (group A) and cows exhibiting no oestrus and ovulation (group B) were also evaluated. In contrast to the mean area of the CL and the mean concentration of P4 on day 0, the mean area of the largest follicles between the two groups on day 0 differed significantly. Significant decreases in the percentage changes relative to the area of the CL and P4 concentration or increases in the percentage changes relative to the area of the largest follicle during the experiment were detected in both groups; however, there were no group differences. Treatment of dairy cows with two injections of prostaglandins (cloprostenol or dinoprost) at an 8-h interval resulted in more cows being observed in oestrus within 5 days after treatment and having significantly higher pregnancy rate than those treated with a single prostaglandin injection. 相似文献
6.
7.
LOW RELEASE OF SELENIUM FROM RECOVERED RUMINAL PELLETS 总被引:1,自引:0,他引:1
The effectiveness of selenium pellets in grazing Merino sheep was examined by comparing the selenium status of treated and untreated animals over a 13 month period. The selenium status of treated sheep, as measured by blood glutathione peroxidase levels, had reached a maximum 3 months after treatment and there was a marked decline between 5 and 13 months. All pellets were recovered from treated sheep at slaughter this confirmed that the observed decline was not due to a loss of pellets.
In a separate study sheep were slaughtered 14 months after treatment and some of the recovered pellets were readministered to sheep maintained on a low selenium diet. The selenium status of the sheep receiving recovered pellets remained low. This bioassay technique indicated that there was little available selenium released from these pellets. The selenium status of sheep given previously unused pellets was declining after 18 weeks. 相似文献
In a separate study sheep were slaughtered 14 months after treatment and some of the recovered pellets were readministered to sheep maintained on a low selenium diet. The selenium status of the sheep receiving recovered pellets remained low. This bioassay technique indicated that there was little available selenium released from these pellets. The selenium status of sheep given previously unused pellets was declining after 18 weeks. 相似文献
8.
Wilkins RW 《Science (New York, N.Y.)》1977,198(4313):185-187
Minerals of the Broken Hill lode in New South Wales, Australia, have a rich assemblage of fluid inclusions. Most typically they contain a high-salinity aqueous liquid and a high-density carbon dioxide and methane gas. Northerly trending shear zones in the area are characterized by a distinct assemblage of inclusions. The inclusions provide a record of the sequence of metamorphic fluids since the period of high-grade metamorphism. Inclusions from the period of ore formation have been eliminated by repeated deformation and recrystallization. 相似文献
9.
10.
1. This study compared the effects of electrical stunning delivered using high and low frequency waveforms on carcase and meat quality of turkeys processed under commercial conditions. 2. The use of a high frequency waveform (1400 Hz) resulted in a faster bleedout and an improvement in carcase quality associated with a substantial reduction in haemorrhagic downgrading conditions. 3. Frequency of the applied waveform influenced breast muscle pH and colour although the magnitude of the differences was considered to be of minimal significance in influencing consumer perception. 相似文献