首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   102877篇
  免费   5731篇
  国内免费   65篇
林业   3598篇
农学   2890篇
基础科学   680篇
  12062篇
综合类   17529篇
农作物   3774篇
水产渔业   4955篇
畜牧兽医   55820篇
园艺   1100篇
植物保护   6265篇
  2018年   1344篇
  2017年   1563篇
  2016年   1441篇
  2015年   1199篇
  2014年   1526篇
  2013年   3797篇
  2012年   2720篇
  2011年   3423篇
  2010年   2204篇
  2009年   2272篇
  2008年   3329篇
  2007年   3114篇
  2006年   3045篇
  2005年   2694篇
  2004年   2608篇
  2003年   2649篇
  2002年   2435篇
  2001年   3326篇
  2000年   3399篇
  1999年   2593篇
  1998年   1028篇
  1997年   1050篇
  1995年   1218篇
  1994年   1057篇
  1993年   1008篇
  1992年   2268篇
  1991年   2504篇
  1990年   2256篇
  1989年   2256篇
  1988年   2132篇
  1987年   2235篇
  1986年   2253篇
  1985年   2157篇
  1984年   1742篇
  1983年   1518篇
  1982年   1064篇
  1979年   1680篇
  1978年   1358篇
  1977年   1199篇
  1976年   1177篇
  1975年   1243篇
  1974年   1527篇
  1973年   1559篇
  1972年   1454篇
  1971年   1340篇
  1970年   1260篇
  1969年   1206篇
  1968年   1066篇
  1967年   1147篇
  1966年   1003篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
The medical records of 38 horses with puncture wounds of the navicular bursa were reviewed. Only 12 horses had a satisfactory outcome (breeding or riding). Of the remaining 26 horses, 19 were euthanized, five were sold due to persistent severe lameness, one died, and one was lost to long-term follow-up. Different combinations of conservative management prior to surgical debridement and drainage of the navicular bursa were unsuccessful in resolving the condition. Horses that were treated surgically within 1 week of the injury and had a hind leg affected had the best chance of a satisfactory outcome. Additional wound debridement was necessary in 15 horses after initial surgical treatment. The most common complications encountered were navicular bone osteomyelitis and sepsis of the deep digital flexor tendon. Thirteen of 14 horses that had rupture of the deep digital flexor tendon and subluxation of the distal interphalangeal joint had an unsatisfactory outcome. One mare subsequently developed ankylosis of the distal interphalangeal joint and was a useful brood mare. Two horses that had biaxial palmar digital neurectomy because of persistent lameness were later euthanized because of navicular bone fracture and rupture of the deep digital flexor tendon. Results from limited numbers of bacterial cultures and antibiotic sensitivities suggest that penicillin and an aminoglycoside antibiotic should be used as initial antibiotic therapy. Immediate surgical debridement and appropriate antibiotic treatment are recommended as the minimum therapy for penetrating wounds of the navicular bursa in horses.  相似文献   
62.
Thirteen mixed-breed beef bulls, 1 to 4 years old, were used to determine the effect of live and dead filarial nematodes, Setaria labiatopapillosa, placed in the vaginal cavity of the testes. When dead worms were used, granulomatous lesions developed on the tunica vaginalis parietalis in 7 of 8 testes. The lesions were similar to those seen in some clinical cases of periorchitis. Similar lesions developed in 5 of 6 testes after live worms were implanted in the vaginal cavity of the testes and tetramisole (8 mg/kg) was injected subcutaneously 6 days after implantation. When live worms were implanted and tetramisole was not given, lesions developed in 3 of 6 testes. It was concluded that the granulomatous reaction was a local response to dead or killed S labiatopapillosa.  相似文献   
63.
Softening process and total antioxidant activity were evaluated in kiwifruit differently exposed to light intensity and harvested at two different times (October 10 and November 14). Fruit was stored for 2 months at 0 °C (S1) and then maintained for a week at ambient temperature (S2). The results showed that fruit harvested later presented a faster softening rate during storage than fruit harvested earlier, even if antioxidant activity did not change. Light-exposed fruit showed higher flesh firmness than that of shaded ones. Polygalacturonase activity was higher in kiwifruit maintained for a week at ambient temperature after cool storage and, in particular the highest value was recorded in fruit harvested later. The behaviour of β-galactosidase was different: it did not show changes in fruit harvested later and significantly decreased in light- and shade-exposed fruit harvested earlier.  相似文献   
64.
65.
In addition to the well-defined phenolic estrogens in human pregnancy urine there appears to be another estrogenic substance which is a neutral non-ketonic compound.  相似文献   
66.
67.
68.
69.
70.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号