全文获取类型
收费全文 | 436篇 |
免费 | 65篇 |
国内免费 | 15篇 |
专业分类
林业 | 41篇 |
农学 | 64篇 |
基础科学 | 18篇 |
23篇 | |
综合类 | 105篇 |
农作物 | 7篇 |
水产渔业 | 2篇 |
畜牧兽医 | 253篇 |
园艺 | 1篇 |
植物保护 | 2篇 |
出版年
2023年 | 11篇 |
2022年 | 9篇 |
2021年 | 25篇 |
2020年 | 25篇 |
2019年 | 23篇 |
2018年 | 13篇 |
2017年 | 23篇 |
2016年 | 15篇 |
2015年 | 24篇 |
2014年 | 28篇 |
2013年 | 23篇 |
2012年 | 26篇 |
2011年 | 30篇 |
2010年 | 20篇 |
2009年 | 30篇 |
2008年 | 17篇 |
2007年 | 13篇 |
2006年 | 15篇 |
2005年 | 23篇 |
2004年 | 13篇 |
2003年 | 11篇 |
2002年 | 8篇 |
2001年 | 9篇 |
2000年 | 7篇 |
1999年 | 10篇 |
1998年 | 8篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1995年 | 5篇 |
1994年 | 6篇 |
1993年 | 6篇 |
1992年 | 6篇 |
1991年 | 7篇 |
1990年 | 6篇 |
1989年 | 3篇 |
1988年 | 7篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1983年 | 1篇 |
排序方式: 共有516条查询结果,搜索用时 15 毫秒
21.
22.
通过浮顶油罐浮顶焊缝断裂漏油的实例,从油罐设计、施工、检修和油罐运行管理四个方面对浮顶焊缝断裂的原因,作了较详细的分析,同时提出了防止焊缝断裂的整治措施,主要从油罐设计、大修时的补救及油罐的日常运行管理等三个方面进行了探讨。 相似文献
23.
An 8-year-old show-jumper gelding was referred for examination as a result of a purchase dispute for reported back pain. Clinical examination identified back pain and atrophy of the left semimembranosus and semitendinosus muscles, but no lameness. Standing pelvic radiography demonstrated a chronic nonunion fracture of the left ischium, the clinical significance of which was uncertain. The apparent back pain was thought to be probably unrelated to the pelvic lesion. We conclude that chronic ischial fracture in the horse can lead to specific atrophy of the semimembranosus and semitendinosus muscles, which originate from this bone. 相似文献
24.
应用断裂力学的J积分理论,推导了含裂纹管道的弹性评定方程和失效评定曲线表达式,对存在表面裂纹的管道承压能力进行评定,并用此方法对输库输油管道的承压能力进行评定,所得结果与现场试验数据相吻合,与美国AMOCO公司对该管道分析的结论相一致,说明该评定方法是正确的,具有推广应用价值。 相似文献
25.
26.
J?rgen Lauritzen?JensenEmail author Per-Johan?Gustafsson 《Journal of Wood Science》2004,50(2):123-129
Splitting failure in beam splice joints with glued-in rods parallel to grain in endwood subjected to pure shear is considered. A simple theoretical expression based on beam-on-elastic-foundation theory and quasi-non-linear fracture mechanics is presented for calculation of the joint strength. Tests were conducted on jointed beams in a four-point bending test setup in which the joints were located at the point of pure shear force. Hardwood dowels with a diameter of 12mm and a glued-in length of 120mm were used as rods, and various beam cross sections and dowel configurations were tested. The theory presented is found to agree well with test results in all cases in which the edge distance of the glued-in rods is relatively small. Some test results indicate that the theory may be conservative in case of large edge distances. 相似文献
27.
28.
29.
30.
S. Bumbacher M. F. Bryner A. E. Fürst F. Del Chicca S. K. Ringer M. A. Jackson 《Equine Veterinary Education》2014,26(1):27-31
A closed complete mid‐diaphyseal spiral fracture of the left femur in a one‐year‐old donkey was treated with a 4.5 mm titanium locking compression plate distal femur (LCP‐DF)1. This plate was originally manufactured for human orthopaedics, primarily for femoral osteosynthesis. The LCP‐DF1 has a distal head plate that was advantageous in this case because the distal fragment was smaller. Post operative radiographs showed optimal femoral reconstruction and a callus was present 3 weeks after surgery. The donkey was sound at the walk and trot 2 months after surgery. Radiographs taken 5 months after surgery showed stable implants and complete healing without complications. 相似文献