全文获取类型
收费全文 | 128篇 |
免费 | 2篇 |
专业分类
林业 | 1篇 |
农学 | 3篇 |
19篇 | |
综合类 | 40篇 |
水产渔业 | 2篇 |
畜牧兽医 | 61篇 |
植物保护 | 4篇 |
出版年
2015年 | 2篇 |
2014年 | 2篇 |
2013年 | 2篇 |
2012年 | 2篇 |
2011年 | 4篇 |
2009年 | 2篇 |
2008年 | 2篇 |
2007年 | 2篇 |
2006年 | 3篇 |
2005年 | 5篇 |
2004年 | 4篇 |
2003年 | 3篇 |
2002年 | 3篇 |
2001年 | 6篇 |
2000年 | 13篇 |
1999年 | 10篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1991年 | 2篇 |
1987年 | 2篇 |
1984年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1972年 | 2篇 |
1971年 | 3篇 |
1969年 | 2篇 |
1968年 | 2篇 |
1967年 | 4篇 |
1963年 | 1篇 |
1960年 | 1篇 |
1959年 | 1篇 |
1952年 | 1篇 |
1944年 | 1篇 |
1934年 | 1篇 |
1928年 | 1篇 |
1925年 | 1篇 |
1924年 | 1篇 |
1923年 | 1篇 |
1915年 | 1篇 |
1911年 | 1篇 |
1902年 | 1篇 |
1899年 | 1篇 |
1895年 | 1篇 |
1893年 | 1篇 |
排序方式: 共有130条查询结果,搜索用时 15 毫秒
81.
82.
Susan M. Newell DVM MS John P. Graham MVB MSc Gregory D. Roberts DVM MS Pamela E. Ginn DVM Jay M. Harrison MS 《Veterinary radiology & ultrasound》1999,40(1):40-43
The normal sonographic appearance of the stomach in various degrees of distension, the duodenum, the small intestine, and the large intestine was determined in awake and sedated cats. The mean stomach rugal fold thickness was 4.38 mm, and the interrugal thickness was 2.03 mm. No significant difference in stomach wall thickness was seen when the stomach was empty, half full, or full. The duodenal wall thickness was significantly greater than other parts of the small intestine, and this difference was accentuated by sedation (awake mean 2.4 mm; sedated mean 2.71 mm). The mean small intestinal wall thickness was 2.1 mm, and the mean colonic wall thickness was 1.67 mm. The five characteristic sonographic layers similar to that seen in the gastrointestinal tract of other species were routinely identified at all regions of the feline gastrointestinal tract. 相似文献
83.
84.
Five Zirconi samples from Pennsylvania, Virginia, and North Carolina yield discordant uranium-lead ages which suggest an original age of 820 million years and an episodic lead loss at 240 million years. The indicated age of lead loss is interpreted as the age of movement of the Blue Ridge thrust sheet. 相似文献
85.
86.
87.
88.
89.
90.
Shepard FP Curray JR Newman WA Bloom AL Newell ND Tracey JI Veeh HH 《Science (New York, N.Y.)》1967,157(3788):542-544
Investigation of 33 islands, scattered widely across the Caroline and Marshall Island groups in the Central Pacific revealed no emerged reefs in which corals had unquestionably formed in situ, or other direct evidence of postglacial high stands of sea level. Low unconsolidated rock terraces and ridges of reefflat islands, mostly lying between tide levels, were composed of rubble conglomerates; carbon-14 dating of 11 samples from the conglomerates so far may suggest a former slightly higher sea level (nine samples range between 1890 and 3450 and one approaches 4500 years ago). However, recent hurricanes have produced ridges of comparable height and material, and in the same areas relics from World War II have been found cemented in place. Thus these datings do not in themselves necessarily indicate formerly higher sea levels. Rubble tracts are produced by storms under present conditions without any change in datum, and there seems to be no compelling evidence that they were not so developed during various periods in the past. 相似文献