全文获取类型
收费全文 | 853篇 |
免费 | 33篇 |
国内免费 | 3篇 |
专业分类
林业 | 27篇 |
农学 | 7篇 |
基础科学 | 13篇 |
36篇 | |
综合类 | 296篇 |
农作物 | 8篇 |
水产渔业 | 9篇 |
畜牧兽医 | 454篇 |
园艺 | 11篇 |
植物保护 | 28篇 |
出版年
2023年 | 5篇 |
2022年 | 5篇 |
2020年 | 5篇 |
2019年 | 7篇 |
2018年 | 8篇 |
2014年 | 8篇 |
2012年 | 45篇 |
2011年 | 42篇 |
2010年 | 10篇 |
2009年 | 17篇 |
2008年 | 44篇 |
2007年 | 41篇 |
2006年 | 49篇 |
2005年 | 56篇 |
2004年 | 45篇 |
2003年 | 52篇 |
2002年 | 42篇 |
2001年 | 28篇 |
2000年 | 50篇 |
1999年 | 17篇 |
1997年 | 6篇 |
1995年 | 7篇 |
1993年 | 15篇 |
1992年 | 10篇 |
1991年 | 7篇 |
1990年 | 9篇 |
1989年 | 13篇 |
1988年 | 8篇 |
1987年 | 7篇 |
1984年 | 6篇 |
1981年 | 4篇 |
1978年 | 6篇 |
1977年 | 5篇 |
1973年 | 6篇 |
1972年 | 4篇 |
1971年 | 5篇 |
1967年 | 5篇 |
1966年 | 4篇 |
1963年 | 5篇 |
1959年 | 4篇 |
1958年 | 14篇 |
1957年 | 13篇 |
1956年 | 7篇 |
1955年 | 8篇 |
1954年 | 11篇 |
1953年 | 10篇 |
1948年 | 6篇 |
1943年 | 5篇 |
1932年 | 4篇 |
1892年 | 4篇 |
排序方式: 共有889条查询结果,搜索用时 15 毫秒
2.
3.
4.
Klopfer LE 《Science (New York, N.Y.)》1986,232(4753):1010-1011
5.
Viruses and virus-like particles detected during examination of feces from calves and piglets with diarrhea 总被引:1,自引:1,他引:0
下载免费PDF全文
![点击此处可从《The Canadian veterinary journal. La revue veterinaire canadienne》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Durham PJ Hassard LE Norman GR Yemen RL 《The Canadian veterinary journal. La revue veterinaire canadienne》1989,30(11):876-881
A total of 763 fecal or intestinal samples from diarrheic calves and piglets were examined for viral content by immunofluorescence, electron microscopy or cell culture. Routine fluorescent antibody and cultural tests detected rotavirus (n=126), coronavirus (n=80) and bovine viral diarrhea virus (n=13). Electron microscopy detected rotaviruses (n=24) and coronaviruses (n=17) not identified by standard fluorescent antibody tests. Other viruses detected by electron microscopy included Breda virus-like particles (n=49), astroviruses (n=1), caliciviruses (n=1), rhabdoviruses (n=1), parvoviruses (n=2), enteroviruses (n=3), togavirus-like particles (n=2), and “chained” particles (n=5). Mixtures of several of the viruses were detected in a number of fecal samples.
The survey emphasized the value of electron microscopy as a broad-spectrum diagnostic tool.
相似文献6.
A model is proposed for the East Coast Magnetic Anomaly that, for the first time, incorporates an observed basement feature-a normal fault that consistently lies below the landward flank of the anomaly. The East Coast Magnetic Anomaly is similar to slope anomalies found over passive continental margins in many parts of the world. Thus the proposed model can be used to interpret slope anomalies in general. 相似文献
7.
Methylation of tin by estuarine microorganisms 总被引:1,自引:0,他引:1
Mixed inoculums of microorganisms from Chesapeake Bay sediments transformed inorganic tin (SnCl(4) . 5H(2)O) to organotin compounds. Dimethyltin and trimethyltin species were identified as products by gas chromatography-mass spectrometry. Methylated tin species were not observed in sterile controls or in poisoned controls. Thus, estuarine microorganisms have the potential for transforming tin to toxic organotins and for mobilizing tin in the ecosystem. 相似文献
8.
9.
Archeological deposits have been discovered in three pimple mounds on the upper Texas coast. Such incorporation indicates that (i) these particular mounds are aggradational rather than erosional in origin; (ii) mound formation continued until at least A.D. 1100 to 1200; (iii) each mound took 300 to 500 years to form; (iv) mounds within the same mound field did not form simultaneously; (v) certain Gulf Coast pimple mounds have archeological research potential; and (vi) archeological data also offer a means for investigating mound formation. 相似文献
10.
Crenshaw JD Boyd RD Campbell JM Russell LE Moser RL Wilson ME 《Journal of animal science》2007,85(12):3442-3453
Four experiments involving 265, 410, 894, and 554 sows (Exp. 1 to 4, respectively) were conducted to determine the effect of spray-dried plasma (SDP) at 0 or 0.25% (Exp. 1 and 2) and 0 or 0.50% (Exp. 3 and 4) in lactation diets on average daily feed disappearance (FD), sum of sow BW, fetal and placental loss from d 110 gestation to weaning (SWL), litter size at weaning, litter weight at weaning, and average days from weaning to first estrus (WEI). Experiments 1, 3, and 4 were conducted during summer months, and Exp. 2 was conducted during fall to winter months. Experiment 1 used only parity 1 and parity 2 sows and Exp. 4 used only mature (>2 parities) sows, whereas Exp. 2 and 3 used all parity groups. Sows fed SDP in Exp. 1 had increased (P < 0.01) FD and a tendency for reduced (P = 0.06) SWL and WEI (P = 0.06). Sows fed SDP in Exp. 2 had a tendency for increased (P = 0.09) sow BW at weaning and reduced (P = 0.09) SWL, whereas other variables were not different between diets. Parity 1 and 2 sows fed SDP in Exp. 3 had increased (P < 0.01) FD, but mature sows fed SDP had reduced (P = 0.02) FD. Pig survival and litter size at weaning for all parity groups was not different between diets. The WEI for parity 1 sows fed SDP was reduced (P = 0.02) and tended to be reduced (P = 0.10) for mature sows fed SDP, but was not different between diets for parity 2 sows. More parity 1 sows fed SDP were detected (P = 0.01) in estrus 4 to 6 d after weaning, and fewer were detected (P < 0.01) in estrus 6 d after weaning compared with control parity 1 sows. In Exp. 4, FD was reduced (P < 0.01) for mature sows fed SDP; however, litter weight and average pig BW at weaning was increased (P < 0.01) with more (P < 0.01) marketable pigs (pig BW > 3.6 kg) weaned per litter. Relatively low dietary levels of SDP (0.25 to 0.50%) fed to parity 1 sows farrowed during summer months increased lactation FD and reduced WEI. Mature sows fed SDP during summer months consumed less lactation feed without compromising WEI, but had an increased litter weight, average pig BW, and number of marketable pigs at weaning. 相似文献