全文获取类型
收费全文 | 13121篇 |
免费 | 715篇 |
国内免费 | 397篇 |
专业分类
林业 | 880篇 |
农学 | 542篇 |
基础科学 | 327篇 |
2195篇 | |
综合类 | 2807篇 |
农作物 | 575篇 |
水产渔业 | 1029篇 |
畜牧兽医 | 4393篇 |
园艺 | 475篇 |
植物保护 | 1010篇 |
出版年
2024年 | 40篇 |
2023年 | 129篇 |
2022年 | 257篇 |
2021年 | 380篇 |
2020年 | 425篇 |
2019年 | 377篇 |
2018年 | 373篇 |
2017年 | 447篇 |
2016年 | 362篇 |
2015年 | 390篇 |
2014年 | 484篇 |
2013年 | 743篇 |
2012年 | 867篇 |
2011年 | 1028篇 |
2010年 | 644篇 |
2009年 | 589篇 |
2008年 | 859篇 |
2007年 | 819篇 |
2006年 | 738篇 |
2005年 | 712篇 |
2004年 | 704篇 |
2003年 | 653篇 |
2002年 | 555篇 |
2001年 | 141篇 |
2000年 | 131篇 |
1999年 | 127篇 |
1998年 | 97篇 |
1997年 | 89篇 |
1996年 | 83篇 |
1995年 | 71篇 |
1994年 | 64篇 |
1993年 | 55篇 |
1992年 | 69篇 |
1991年 | 61篇 |
1990年 | 69篇 |
1989年 | 58篇 |
1988年 | 49篇 |
1987年 | 52篇 |
1986年 | 36篇 |
1985年 | 33篇 |
1984年 | 35篇 |
1983年 | 42篇 |
1982年 | 30篇 |
1981年 | 28篇 |
1980年 | 28篇 |
1979年 | 24篇 |
1978年 | 25篇 |
1976年 | 21篇 |
1975年 | 22篇 |
1974年 | 18篇 |
排序方式: 共有10000条查询结果,搜索用时 265 毫秒
31.
Geoffrey W Smith David S Rotstein Cecil F Brownie 《Journal of veterinary diagnostic investigation》2004,16(4):356-359
Abdominal fat necrosis was diagnosed in an 11-year-old female pygmy goat with a 10-day history of lethargy, anorexia, and progressive abdominal distension. Gross necropsy findings revealed multiple firm, dark yellow, nodular masses of fat throughout the abdominal cavity, which compressed several abdominal organs including the rumen, small intestine, spiral colon, and gall bladder. Histologically, multiple to coalescing adipocyte necrosis, saponification, and infiltration with variable numbers of macrophages, lymphocytes, and plasma cells was observed. Fat necrosis in this case was attributed to tall fescue toxicity based on the presence of high levels of endophyte (Neotyphodium coenophialum)-infected fescue identified in the goat's pasture. This is the first known report of abdominal fat necrosis in a goat and demonstrates the fat necrosis syndrome of fescue toxicosis in ruminants. 相似文献
32.
Paolo Zucca Giovanni Di Guardo Roberto Pozzi-Mucelli Dino Scaravelli Marco Francese 《Journal of zoo and wildlife medicine》2004,35(3):391-394
A mature male Risso's dolphin (Grampus griseus) stranded along the coasts of Friuli Venezia Giulia, northeast Italy, in May 2001. Parasitic infection with Crassicauda grampicola is often found in the tympanic bullae and pterygoid sinuses in many of the Risso's dolphins examined from the same area. For this reason, it was decided to perform computed tomography of the head to assess this imaging technique for the diagnosis of crassicaudosis in dolphins. A full postmortem examination confirmed the pathologic findings of the computed tomography scan. This technique can be considered a useful adjunct in the diagnosis of cranial crassicaudosis in live dolphins. 相似文献
33.
Evaluation of the cationic trypsinogen gene for potential mutations in miniature schnauzers with pancreatitis
下载免费PDF全文
![点击此处可从《Canadian journal of veterinary research》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Micah A. Bishop J?rg M. Steiner Lisa E. Moore David A. Williams 《Canadian journal of veterinary research》2004,68(4):315-318
The purpose of this study was to evaluate the cationic trypsinogen gene in miniature schnauzers for possible mutations. Genetic mutations have been linked with hereditary pancreatitis in humans. Four miniature schnauzers were selected on the basis of a clinical history of pancreatitis. One healthy miniature schnauzer and 1 healthy mixed breed canine were enrolled as controls. DNA was extracted from these canines using a commercial kit. Primers were designed to amplify the entire canine cationic trypsinogen cDNA sequence. A polymerase chain reaction (PCR) was performed and products were purified and sequenced. All sequences were then compared. The healthy control canine, a healthy miniature schnauzer, and the 4 miniature schnauzers with pancreatitis showed identical sequences of the cationic trypsinogen gene to the published sequence. We conclude that, in contrast to humans with hereditary pancreatitis, mutations of the cationic trypsinogen gene do not play a major role in the genesis of pancreatitis in the miniature schnauzer. 相似文献
34.
Adrian Mutlow Ramiro Isaza James W Carpenter David E Koch Robert P Hunter 《Journal of zoo and wildlife medicine》2004,35(4):489-496
Using a crossover study design, the pharmacokinetics of carfentanil and naltrexone after i.v., i.m., and s.c. administration were determined in eight domestic goats (Capra hircus). Serial blood samples were taken up to 120 hr after carfentanil administration, and the plasma drug concentrations were determined using liquid chromatography and mass spectroscopy. All goats were immobilized with 40 microg/kg carfentanil i.m., although the resulting neurologic effects varied considerably. Plasma profiles showed rapid carfentanil absorption and a simple biphasic decline for 12-48 hr. Naltrexone given at 100 mg naltrexone/mg carfentanil 30 min after carfentanil administration produced rapid reversal of immobilization after all routes of administration. Variable fluctuations in the naltrexone plasma concentrations during the first 2.5-3.5 hr were observed, followed by a more consistent biphasic decline. The time to standing was significantly shorter after i.v. compared with s.c. naltrexone, although the time difference (1 min) had little clinical relevance. No statistically significant differences between the naltrexone pharmacokinetic parameters measured for the three routes of naltrexone administration were identified, although the recoveries after i.m. administration were, subjectively, the smoothest. The carfentanil half-life did not differ significantly in the goats given naltrexone by different routes. Although it is currently recommended that the naltrexone dose be divided into s.c. and i.v. portions, this practice does not appear to offer any benefit. 相似文献
35.
Tropical Animal Health and Production - 相似文献
36.
37.
Radiographic,computed tomographic,and arthroscopic diagnosis of radioulnar incongruence in dogs with medial coronoid disease
下载免费PDF全文
![点击此处可从《Veterinary surgery : VS》网站下载免费的PDF全文](/ch/ext_images/free.gif)
38.
39.
为了解内蒙古地区羊屠宰场各屠宰环节致泻性大肠杆菌和沙门氏菌的携带情况,评估是否存在污染风险,选取不同规模屠宰场,用棉拭子法分别采集不同屠宰环节样品349份,36 h内进行试验;应用PCR方法分离鉴定病原菌,对鉴定为致泻性大肠杆菌的分离株进行16S r DNA测序并构建系统发育树。结果显示:从刚宰杀的羊胴体表面和环境中共分离到致泻性大肠杆菌12株,其中11株携带毒力基因elt,1株携带毒力基因eae和elt;大中型屠宰场(1.21%)的致泻性大肠杆菌阳性率低于小型屠宰场(5.43%),不同规模屠宰场的预冷间均未检出致泻性大肠杆菌和沙门氏菌;从屠宰环境中分离出1株携带inv A基因的沙门氏菌,阳性率为0.29%;经高压冲洗和排酸预冷等屠宰工艺后,在羊胴体表面均未发现致泻性大肠杆菌和沙门氏菌。 相似文献
40.
PP2C是一大类重要的蛋白磷酸酶,广泛参与不同的逆境胁迫响应。为了解PP2C基因在干旱响应中的功能,以亚洲棉石系亚1号为材料,利用RT-PCR方法从中克隆了GaPP2C24基因,并对该基因进行了生物信息学分析,荧光定量PCR研究了其在亚洲棉不同组织和干旱胁迫下的表达情况。结果表明,GaPP2C24基因CDS序列全长为1 251 bp,编码416个氨基酸。序列同源比对发现,GaPP2C24与其他植物的PP2C氨基酸序列有较高的相似性,其中与可可树(EOY33930.1)、黄麻(OMO91132.1)的相似性分别为85%,84%。进化分析表明,GaPP2C24与同属锦葵目的黄麻聚在一支,亲缘关系最近,与可可树的亲缘关系次之。实时荧光定量PCR结果表明,GaPP2C24基因在子叶、下胚轴、胚根、叶、茎和根均有表达,且在茎中的表达量最高,根中次之。GaPP2C24受干旱胁迫的诱导表达,其在根和叶片中的相对表达量在处理1 h后最高,分别达到对照的53.9,6.9倍,推测该基因在棉花干旱响应中有重要作用。 相似文献