全文获取类型
收费全文 | 238篇 |
免费 | 18篇 |
专业分类
林业 | 1篇 |
农学 | 2篇 |
基础科学 | 1篇 |
8篇 | |
综合类 | 53篇 |
农作物 | 3篇 |
水产渔业 | 6篇 |
畜牧兽医 | 166篇 |
园艺 | 1篇 |
植物保护 | 15篇 |
出版年
2020年 | 2篇 |
2019年 | 5篇 |
2018年 | 10篇 |
2017年 | 6篇 |
2016年 | 6篇 |
2015年 | 3篇 |
2014年 | 7篇 |
2013年 | 12篇 |
2012年 | 5篇 |
2011年 | 5篇 |
2010年 | 15篇 |
2009年 | 19篇 |
2008年 | 8篇 |
2007年 | 6篇 |
2006年 | 3篇 |
2005年 | 4篇 |
2004年 | 8篇 |
2003年 | 7篇 |
2002年 | 3篇 |
2001年 | 12篇 |
2000年 | 2篇 |
1999年 | 6篇 |
1998年 | 14篇 |
1997年 | 8篇 |
1996年 | 13篇 |
1995年 | 5篇 |
1994年 | 6篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1991年 | 8篇 |
1990年 | 6篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1982年 | 2篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1973年 | 2篇 |
1970年 | 1篇 |
1966年 | 1篇 |
1960年 | 1篇 |
1947年 | 1篇 |
1895年 | 2篇 |
1886年 | 2篇 |
1885年 | 1篇 |
1884年 | 2篇 |
1883年 | 6篇 |
排序方式: 共有256条查询结果,搜索用时 0 毫秒
51.
Pets and the elderly. A social work perspective 总被引:1,自引:0,他引:1
E L Ryder 《Veterinary Clinics of North America: Small Animal Practice》1985,15(2):333-343
Pets can provide companionship, affection, and psychosocial stimulus for elderly people in a program that is planned and supervised by professionals who are knowledgeable about both the humans and the animals and who are clear about the goals to be achieved. Ineffective programs, or programs with negative effects, have developed when the proponents assumed that any pet would be good for elderly persons either living alone or in a residential center. A much-needed aspect of any people-pet program is the collection, analysis, and reporting of social data to provide a better information base for planning the use of pets in a therapeutic setting. 相似文献
52.
Progressive ethmoidal haematoma was diagnosed in 12 Thoroughbreds, 1 part- Arab and 1 stock horse. Ages ranged from 3 to 18 years and both males and females were affected. Diagnosis was based on history, clinical signs, endoscopic and radiographic findings, and was confirmed histologically in 10 cases. Eleven (78%) of the lesions were unilateral and 3 (22%) were bilateral. Two horses were euthanased on diagnosis, 4 were treated conservatively. Of the latter, 3 were euthanased 6 to 24 months after diagnosis, due to progression of the lesions, while 1 case resolved completely within 13 months. Eight horses were treated by surgical excision of the lesion. Three died in the post-operative period, 3 were euthanased within 48 months after recurrence of the condition, and 2 had no recurrence within 60 and 72 months, respectively. 相似文献
53.
54.
55.
56.
Detection of disease-specific PrP in the distal ileum of cattle exposed orally to the agent of bovine spongiform encephalopathy 总被引:6,自引:0,他引:6
Terry LA Marsh S Ryder SJ Hawkins SA Wells GA Spencer YI 《The Veterinary record》2003,152(13):387-392
The immunohistochemical localisation of the disease-specific protein, PrP(Sc), was examined in the distal ileum of cattle up to 40 months after they had been exposed orally to the agent of bovine spongiform encephalopathy (BSE), in the intestines and mesenteric lymph nodes of an additional group of cattle, killed six months after a similar exposure, and in the distal ileum of naturally occurring clinical cases of BSE. PrP(Sc) was detected, mainly in macrophages, in a small proportion of the follicles of Peyer's patches in the distal ileum of the experimentally exposed cattle throughout much of the course of the disease. The observations are in agreement with the infectivity data derived from mouse bioassays of the distal ileum. At the later stages of the disease, the proportion of immunostained follicles increased as the total number of follicles decreased with age. In the additional experimental group of cattle, PrP(Sc) was confined to the Peyer's patches in the distal ileum. No immunostaining was detected in the lymphoid tissue of the distal ileum of naturally occurring clinical cases of BSE. In some of the clinically affected experimentally induced and naturally occurring cases of BSE there was sparse immunostaining of the neurons of the distal ileal myenteric plexus. 相似文献
57.
Chaplin MJ Barlow N Ryder S Simmons MM Spencer Y Hughes R Stack MJ 《Research in veterinary science》2002,72(1):37-43
Seventeen clinically suspect scrapie sheep, and twelve suspected BSE-affected cattle were confirmed using routine histopathological examination by the detection of characteristic spongiform change in the medulla brain region taken at the level of the obex. Three sheep and four cows acquired as controls showed no spongiform change. Five aliquots of brain tissue from each of four brain regions were taken (cerebellum, medulla, frontal cerebral cortex and occipital cerebral cortex) from each of the 36 animals. One aliquot was frozen at -70 degrees C, the others were subjected to one of four autolysis regimes at 3 or 7 days at 25 degrees C or 37 degrees C. All samples were tested by Western immunoblotting for detection of PrP(Sc) using the Prionics - Check test (Prionics AG, Zurich, Switzerland). Further samples of medulla from 15 suspect scrapie cases, 10 healthy sheep, 13 suspect BSE cows and 5 healthy cows, were taken adjacent to the obex, and subjected to autolysis at 37 degrees C for 6, 12, 24 and 48 hours before being fixed in 10 per cent formal saline and subsequently examined by a routine immunohistochemical technique for detection of PrP(Sc) protein. The abnormal protein could not be detected in any of the control animals by either technique. PrP(Sc) could be detected by Western immunoblotting in at least one brain area from all the positive animals after autolysis for 7 days at 37 degrees C. The protein could be detected by immunohistochemistry in all cases which were positive by histopathological examination using all autolysis conditions. From the results of this study it is concluded that autolysis does not significantly compromise the diagnosis of scrapie or BSE by either of these diagnostic methods. 相似文献
58.
59.
DO Gough AG Kosovichev J Toomre E Anderson HM Antia S Basu B Chaboyer SM Chitre J Christensen-Dalsgaard WA Dziembowski A Eff-Darwich JR Elliott PM Giles PR Goode JA Guzik JW Harvey F Hill JW Leibacher MJPFG Monteiro O Richard T Sekii H Shibahashi M Takata MJ Thompson S Vauclair SV Vorontsov 《Science (New York, N.Y.)》1996,272(5266):1296-1300
Global Oscillation Network Group data reveal that the internal structure of the sun can be well represented by a calibrated standard model. However, immediately beneath the convection zone and at the edge of the energy-generating core, the sound-speed variation is somewhat smoother in the sun than it is in the model. This could be a consequence of chemical inhomogeneity that is too severe in the model, perhaps owing to inaccurate modeling of gravitational settling or to neglected macroscopic motion that may be present in the sun. Accurate knowledge of the sun's structure enables inferences to be made about the physics that controls the sun; for example, through the opacity, the equation of state, or wave motion. Those inferences can then be used elsewhere in astrophysics. 相似文献
60.