全文获取类型
收费全文 | 2782篇 |
免费 | 99篇 |
国内免费 | 124篇 |
专业分类
林业 | 381篇 |
农学 | 227篇 |
基础科学 | 173篇 |
208篇 | |
综合类 | 1346篇 |
农作物 | 80篇 |
水产渔业 | 73篇 |
畜牧兽医 | 382篇 |
园艺 | 41篇 |
植物保护 | 94篇 |
出版年
2024年 | 7篇 |
2023年 | 22篇 |
2022年 | 41篇 |
2021年 | 62篇 |
2020年 | 58篇 |
2019年 | 82篇 |
2018年 | 47篇 |
2017年 | 59篇 |
2016年 | 66篇 |
2015年 | 70篇 |
2014年 | 123篇 |
2013年 | 127篇 |
2012年 | 175篇 |
2011年 | 220篇 |
2010年 | 155篇 |
2009年 | 170篇 |
2008年 | 187篇 |
2007年 | 220篇 |
2006年 | 187篇 |
2005年 | 167篇 |
2004年 | 138篇 |
2003年 | 124篇 |
2002年 | 91篇 |
2001年 | 86篇 |
2000年 | 39篇 |
1999年 | 48篇 |
1998年 | 46篇 |
1997年 | 37篇 |
1996年 | 30篇 |
1995年 | 30篇 |
1994年 | 23篇 |
1993年 | 21篇 |
1992年 | 8篇 |
1991年 | 6篇 |
1990年 | 6篇 |
1989年 | 7篇 |
1988年 | 8篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1984年 | 4篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有3005条查询结果,搜索用时 15 毫秒
951.
LONG-TERM FOLLOW-UP OF HYPERTHYROID CATS TREATED WITH IODINE-131 总被引:2,自引:0,他引:2
Margaret R. Slater DVM PhD Andrea Komkov MS DVM Laura E. Robinson DVM MS Dan Hightower DVM 《Veterinary radiology & ultrasound》1994,35(3):204-209
A long-term follow-up study of hyperthyroid cats treated with iodine-131 was conducted at the Texas A&M University Veterinary Teaching Hospital. Between January 1985 and December 1990, 255 cats were treated. Basic demographic data, information on treatment, and diseases at the time of diagnosis were recorded. Two hundred and thirty seven cats had long-term follow-up data collected by telephone interviews with the referring veterinarian and/or the owner on outcome of therapy, diseases that developed during the follow-up period and survival. Risk for developing hyperthyroidism was highest for cats greater than 10 years of age. There was no breed predisposition. Neutered cats were slightly over-represented among the cases compared to intact animals. Eighty-five percent of treated cats became clinically normal and remained euthyroid for a median time of 17.5 months. Four percent remained hyperthyroid and 9% became hypothyroid, requiring thyroid hormone supplementation. 相似文献
952.
我国材种出材率表编制技术规程的研究 总被引:7,自引:0,他引:7
介绍了研究我国材种出材率表编制技术规程的目的意义、研究原则和规程的主要内容,简要评价了这一国家标准预期的经济效益,通过与国际同类标准的对比,阐述了其主要优点,提出了贯彻该标准的措施和建议。 相似文献
953.
954.
955.
狗牙根春季死斑病的研究进展 总被引:2,自引:0,他引:2
在管理水平较高的狗牙根草坪上 ,春季死斑病是一种危害比较严重的病害 ,所以有必要对春季死斑病进行研究 ,本文从春季死斑病的症状、病原菌、及防治措施中真菌剂运用、栽培管理措施及抗病品种的选择等方面进行综述 ,目的是提高狗牙根草坪的管理水平 相似文献
956.
针对魏荆输油管道输量逐年下降的实际情况,为保证管道在低输量条件下安全运行,提出了添加降凝剂综合处理的输送工艺,对添加的GY一3降凝剂进行了室内筛选和评价,通过现场试验,成功地将该管道的最低输量由5000t/d降至2500t/d,实现了魏荆输油管道在低输量条件下的安全输送,经济效益显著。 相似文献
957.
A. T. Fischer Jr. DVM L. Y. Kerr DVM† T. R. O'Brien DVM PhD† 《Veterinary radiology & ultrasound》1987,28(2):42-48
Abdominal discomfort in the foal presents a diagnostic challenge, because the small size of the foal precludes rectal palpation. Standing lateral horizontal beam abdominal radiographs using conventional techniques were evaluated as a diagnostic aid to identify the presence and location of gastrointestinal disorders in foals presented with colic. Forty foals were radiographed prior to surgery (20 foals), necropsy (7 foals), or clinical diagnosis (13 foals). Clinical, surgical, or necropsy findings were then correlated to radiographic findings. Gastrointestinal disease was accurately identified on radiographs as the source of colic in 25 of 26 foals that had surgical or postmortem confirmation. The site of disease, whether gastric, small intestinal, large intestinal, or a combination, was accurately determined from radiographs. Standing lateral abdominal radiographs were determined to be a valuable diagnostic aid in the foal presented with colic. 相似文献
958.
959.
E.T. Lyons S.C. Tolliver S.S. Collins J.H. Drudge D.E. Granstrom 《Veterinary parasitology》1997,70(4):9-240
Data are presented on the last 3 years of a 7-year study (1989–1995) on transmission of natural infections of internal parasites in horse foals (n = 27) born in 1993, 1994, and 1995 on the same pasture on a farm in central Kentucky. The foals were in a closed breeding herd of horses. Research on the first 4 years (1989–1992) of the study was published earlier (Lyons et al., 1991, 1994). Thirty-five species of endoparasites were identified, including 24 species of small strongyles. Monthly, seasonal, and host-age transmission patterns were elucidated for the parasites. Comparison of data between the first 4 years and last 3 years of the study indicates similarities, but also differences, including an increase in prevalence and numbers of Thelazia lacrymalis and Anoplocephala perfoliata. 相似文献
960.
以竹胶合板用酚醛树脂合成工艺为基础,按不同的尿素与苯酚摩尔比.合成一系列苯酚-尿素-甲醛共聚型树脂胶粘剂(PUF),并用该系列胶粘剂难制竹帘胶合板.通过对竹帘胶合板进行性能检测和检测结果分析.表明随尿素与苯酚摩尔比的增加,竹帘胶合板的力学性能总体呈下降趋势,但对静曲强度、弹性模量和冲击强度的影响不显著,对保存强度有很大的影响,将尿素与苯酚的摩尔比控制在0.5以下时.产品可以达到国家相关标准的要求. 相似文献