全文获取类型
收费全文 | 267篇 |
免费 | 19篇 |
专业分类
林业 | 14篇 |
农学 | 2篇 |
5篇 | |
综合类 | 33篇 |
农作物 | 4篇 |
水产渔业 | 44篇 |
畜牧兽医 | 175篇 |
园艺 | 1篇 |
植物保护 | 8篇 |
出版年
2023年 | 4篇 |
2020年 | 4篇 |
2019年 | 9篇 |
2018年 | 12篇 |
2017年 | 4篇 |
2016年 | 4篇 |
2015年 | 4篇 |
2013年 | 13篇 |
2012年 | 13篇 |
2011年 | 7篇 |
2010年 | 19篇 |
2009年 | 12篇 |
2008年 | 8篇 |
2007年 | 7篇 |
2006年 | 4篇 |
2005年 | 10篇 |
2004年 | 4篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 7篇 |
1998年 | 15篇 |
1997年 | 12篇 |
1996年 | 14篇 |
1995年 | 13篇 |
1994年 | 6篇 |
1993年 | 4篇 |
1992年 | 6篇 |
1991年 | 7篇 |
1990年 | 7篇 |
1989年 | 7篇 |
1988年 | 2篇 |
1987年 | 5篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 6篇 |
1979年 | 2篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1971年 | 1篇 |
1964年 | 1篇 |
1961年 | 1篇 |
1909年 | 1篇 |
1905年 | 1篇 |
1904年 | 1篇 |
1903年 | 2篇 |
1899年 | 1篇 |
排序方式: 共有286条查询结果,搜索用时 46 毫秒
21.
Objective To study the efficacy of multiple striate keratotomy for the treatment of persistent corneal erosions suspected to be caused by primary corneal epithelial basement membrane disease.
Design A retrospective study.
Animals 16 dogs, three cats and one Australian dingo.
Procedure A technique called multiple striate keratotomy was used to treat twenty animals suffering from persistent corneal erosions.
Results All persistent corneal erosions healed with only one treatment. Most cases healed within 2 weeks. One case developed a second erosion in the same eye but in a different position to the original erosion.
Conclusions Multiple striate keratotomy is a safe, effective and well tolerated technique for the treatment of persistent corneal erosions thought to be caused by corneal epithelial basement membrane disease. 相似文献
Design A retrospective study.
Animals 16 dogs, three cats and one Australian dingo.
Procedure A technique called multiple striate keratotomy was used to treat twenty animals suffering from persistent corneal erosions.
Results All persistent corneal erosions healed with only one treatment. Most cases healed within 2 weeks. One case developed a second erosion in the same eye but in a different position to the original erosion.
Conclusions Multiple striate keratotomy is a safe, effective and well tolerated technique for the treatment of persistent corneal erosions thought to be caused by corneal epithelial basement membrane disease. 相似文献
22.
A 17-year-old Quarter Horse, Arabian crossbred mare presented with a history of having had abdominal pain for 2 d. At surgery there was 2.6 m of descending colon strangulated within the pedicle of a mesenteric lipoma. The lipoma was resected and the descending colon appeared viable so was replaced, and the mare recovered from anaesthesia. Post-operatively, the mare failed to stabilise so was taken back to surgery. There was 2 m of infarcted descending colon which was resected and anastomosed. A drain and stainless steel stay sutures were incorporated into the ventral suture line. Post-operatively the ventral wound became infected but was resolved with therapy. The diagnosis, surgical and post-operative management and outcome are discussed. 相似文献
23.
A full ophthalmic examination was performed on 40 Siberian husky dogs using direct and indirect ophthalmoscopy, gonloscopy and nasolacrimal cannulation. Eight (20%) of the dogs were found to have distichia, 10 (25%) had excessive medial caruncular hairs, 8 (20%) had absence, displacement, or narrowing of the nasolacrimal puncta, 2 (5%) had bilateral corneal crystalline opacities, and 2 (5%) had unilateral areas of lateral corneal lipidosis. Fifty percent of the dogs had some abnormality of the iridocorneal (drainage) angle. However, in only one of these was the deformity severe enough to require glaucoma prophylaxis. An association between blue iris colour and malformation of the iridocorneal angle was noted. 相似文献
24.
A diagnosis of dicoumarol toxicity in a herd of Friesian cattle was made following investigation of the deaths of three mature cows and eleven yearling heifers. Affected stock had been fed wrapped, bailed silage containing approximately 90% sweet vernal grass ( Anthoxanthum odoratum ). Sweet vernal grass contains coumarin, which can be converted to dicoumarol, a vitamin K antagonist, through the action of moulds. Most deaths were preceded by lethargy, severe anaemia and subcutaneous and internal haemorrhage. Dicoumarol toxicosis was suspected based on clinical signs, necropsy findings and prolonged prothrombin and activated partial thromboplastin times. Dicoumarol analysis of blood from affected animals and silage confirmed the diagnosis. 相似文献
25.
Potential role of soil calcium in recovery of paper birch following ice storm injury in Vermont, USA
Joshua M. Halman Paul G. SchabergGary J. Hawley Christopher F. Hansen 《Forest Ecology and Management》2011,261(9):1539-1545
In recent years, an increased number of mature paper birch (Betula papyrifera Marsh.) and heart-leafed paper birch (B. papyrifera var. cordifolia (Regel) Fern.) in northeastern United States forests have exhibited decline symptoms including foliar loss, reduced fine branching, and tree mortality. We assessed crown health, radial growth, and available soil cations in 2006 as a preliminary assessment of factors that may be influencing paper birch decline. Tree rings began to decrease in width in 1998—the year of a severe region-wide ice storm. All trees (regardless of their current decline status) experienced reduced growth starting in 1998 and tree growth continued to decrease for two years following the ice storm. After this generalized growth decrease, trees that now have vigorous crowns showed a marked increase in growth, whereas trees that now have low crown vigor did not rebound in growth, but instead exhibited a significantly higher incidence of locally absent annual rings. Extractable soil-aluminum (Al), a phytotoxic element mobilized by acid deposition, was significantly higher in soils associated with declining trees compared to those adjacent to vigorous trees. Higher soil calcium (Ca) availability was associated with both vigorous crowns and increased radial growth following the 1998 ice storm. Furthermore, increased soil Ca availability was negatively correlated to the percentage of declining trees, and positively related to increased radial growth, whereas elevation was not significantly associated with either parameter. Although previously overlooked as a factor influencing paper birch recovery from injury, we found that available soil Ca was linked to crown vigor and rebounds in growth following an inciting event. 相似文献
26.
Spatial Variability of Turbulent Mixing in the Abyssal Ocean 总被引:3,自引:0,他引:3
Ocean microstructure data show that turbulent mixing in the deep Brazil Basin of the South Atlantic Ocean is weak at all depths above smooth abyssal plains and the South American Continental Rise. The diapycnal diffusivity there was estimated to be less than or approximately equal to 0.1 x 10(-4) meters squared per second. In contrast, mixing rates are large throughout the water column above the rough Mid-Atlantic Ridge, and the diffusivity deduced for the bottom-most 150 meters exceeds 5 x 10(-4) meters squared per second. Such patterns in vertical mixing imply that abyssal circulations have complex spatial structures that are linked to the underlying bathymetry. 相似文献
27.
The separation of homologous chromosomes during meiosis in eukaryotes is the physical basis of Mendelian inheritance. The core of the meiotic process is a specialized nuclear division (meiosis I) in which homologs pair with each other, recombine, and then segregate from each other. The processes of chromosome alignment and pairing allow for homolog recognition. Reciprocal meiotic recombination ensures meiotic chromosome segregation by converting sister chromatid cohesion into mechanisms that hold homologous chromosomes together. Finally, the ability of sister kinetochores to orient to a single pole at metaphase I allows the separation of homologs to two different daughter cells. Failures to properly accomplish this elegant chromosome dance result in aneuploidy, a major cause of miscarriage and birth defects in human beings. 相似文献
28.
FREDRIK E. HOPPE DVM PHD DAVE A. HAGER DVM PAUL W. POULOS JR. DVM PHD STINA EKMAN DVM P. G. LINDGREN MD PHD 《Veterinary radiology & ultrasound》1986,27(4):99-101
A manual, ultrasound-guided biopsy technique was compared to a new automatic method using a new biopsy device. The liver and the left kidney of 10 dogs were biopsied using the two methods. The specimens from the biopsies were compared for size and quality. Results demonstrate that larger and higher quality samples were obtained with the new automatic method. 相似文献
29.
30.