全文获取类型
收费全文 | 465篇 |
免费 | 68篇 |
国内免费 | 65篇 |
专业分类
林业 | 3篇 |
农学 | 3篇 |
2篇 | |
综合类 | 80篇 |
农作物 | 5篇 |
水产渔业 | 205篇 |
畜牧兽医 | 258篇 |
园艺 | 1篇 |
植物保护 | 41篇 |
出版年
2023年 | 9篇 |
2022年 | 11篇 |
2021年 | 25篇 |
2020年 | 32篇 |
2019年 | 28篇 |
2018年 | 22篇 |
2017年 | 34篇 |
2016年 | 35篇 |
2015年 | 21篇 |
2014年 | 26篇 |
2013年 | 13篇 |
2012年 | 36篇 |
2011年 | 38篇 |
2010年 | 21篇 |
2009年 | 29篇 |
2008年 | 22篇 |
2007年 | 15篇 |
2006年 | 18篇 |
2005年 | 17篇 |
2004年 | 24篇 |
2003年 | 24篇 |
2002年 | 13篇 |
2001年 | 11篇 |
2000年 | 11篇 |
1999年 | 8篇 |
1998年 | 5篇 |
1997年 | 9篇 |
1996年 | 1篇 |
1995年 | 6篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1956年 | 1篇 |
排序方式: 共有598条查询结果,搜索用时 15 毫秒
51.
52.
采用3种不同青贮方法对黄花棘豆进行青贮,并每天按10 g/kg体重剂量给试验羊投服,观察黄花棘豆不同方法青贮后对试验羊的病理组织学影响。结果表明,3种方法青贮黄花棘豆后取得较好效果;试验羊连续投服60 d没有出现中毒症状,仅在试验期间提耳应激时表现为轻度转圈运动;病理组织学观察结果表明,试验羊的肝脏、肾脏、肺脏、小脑、脾脏和心肌等实质性组织均有不同程度的损伤,特别是大脑损伤最为明显,其中黄花棘豆添加酶制剂和"棘防E号"青贮组对试验羊肝脏、肺脏和肾脏的损伤比直接青贮组严重。 相似文献
53.
Daniel A. Heinrich Anne C. Avery Michael S. Henson Jed A. Overmann Aaron K. Rendahl Jillian Z. Walz Davis M. Seelig 《Veterinary and comparative oncology》2019,17(3):365-375
Minimally invasive techniques used to evaluate canine peripheral lymphadenopathy (PLN), including fine needle aspiration biopsy with cytological evaluation (FNAB‐C) and flow cytometry (FC), have benefits and limitations. The cell block (CB) method is an alternate processing technique in which fine needle aspirate biopsy samples are concentrated, fixed, and embedded in paraffin for routine histological processing/staining. Utilizing three observers, we determined the diagnostic value of the CB in evaluating canine PLN across six categories (non‐diagnostic, reactive, inflammatory/infectious, probable lymphoma and lymphoma, metastatic neoplasia) and correlated findings to immunophenotypic and clonal antigen receptor rearrangement results in canine nodal lymphoma. Eighty‐five paired FNAB‐C and CB samples were evaluated from canine patients presenting to the University of Minnesota Veterinary Oncology or Internal Medicine services. Diagnostic quality samples were obtained in 55/85 (65%) CB and 81/85 (95%) FNAB‐C samples, respectively, and nodal pathology impacted CB diagnostic yield. Overall percent agreement between diagnostic‐quality FNAB‐C and CB samples was 86%, but increased to 95% if the categories of lymphoma and probable lymphoma were combined. There was 100% agreement for both the diagnoses of metastatic neoplasia and reactive lymph nodes and 92% agreement for the diagnosis of lymphoma/probable lymphoma. Using immunohistochemistry (IHC), CB samples correctly immunophenotyped 22/23 (96%) cases of B‐cell lymphoma, but only 1/6 (17%) cases of T‐cell lymphoma. IHC was not completed on nine cases of lymphoproliferative disease because of insufficient cellularity. When the CB method (CBM) yielded diagnostic quality samples there was good to excellent agreement with FNAB‐C samples and CB samples were suitable for some IHC tests. 相似文献
54.
八字地老虎核型多角体病毒的寄主范围和室内增殖以及寄主组织病理的研究 总被引:1,自引:0,他引:1
八字地老虎核型多角体病毒(Xc-nNPV)对6种夜蛾科害虫有侵染性,根据害虫感受性的高低顺序为:甘蓝夜蛾、警纹夜蛾>黑三条夜蛾>朽木夜蛾>粘虫>三角夜蛾。Xc-nNPV能够感染八字地老虎幼虫的体壁、脂肪体、气管基质、血细胞和睾丸被膜,而在马氏管、丝腺、消化管、腹神经索和肌肉组织中未发现有多角体的增殖;虫龄影响病毒产量,虫龄越高平均每头幼虫的病毒产量越高,以3龄幼虫的病毒总产量最高。 相似文献
55.
56.
对黄鳝(Monopterus albus)人工感染温和气单胞菌(Aeromonas sobria)的临床症状和病理变化进行了观察。结果显示,感染后12~36h为死亡高峰期,其感染症状与自然发病的黄鳝相似。染病黄鳝的肝脏、肠道和肾脏的病理变化明显,肝细胞变性,肠绒毛脱落,肾小球结构消失并充满大量红细胞;感染后9~27h,肝细胞索排列紊乱,肝细胞肿大并空泡化;感染后3~30h,小肠绒毛脱落,固有层淋巴小结增生,粘膜下层、肌层、浆膜层红细胞增多;感染后3~21h,肾小管上皮细胞肿胀,严重颗粒变性,肾小球上皮细胞坏死;感染后21~30h,肌纤维细胞坏死,大量炎性细胞浸润。 相似文献
57.
Impact of sublethal di‐n‐butyl phthalate on the aquaculture fish species Nile tilapia (Oreochromis niloticus): histopathology and oxidative stress assessment
下载免费PDF全文
![点击此处可从《Aquaculture Research》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Belda Erkmen A Çağlan Karasu Benli Hızlan H Ağuş Zuhal Yıldırım Ramazan Mert Figen Erkoç 《Aquaculture Research》2017,48(2):675-685
Phthalates such as di‐n‐butyl phthalate (DBP) and their esters are widely used plasticizers, their ubiquitous presence in daily life, inevitably leads to their restricted use due to important environmental pollution and health impacts and endocrine disruption potential. The aim of this study was to examine the effects of a sublethal concentration of 10 mg L?1 DBP on haematocrit (HCT) values, gills and liver histology, malondialdehyde (MDA, 2‐thiobarbituric acid‐TBA reactivity) and reduced glutathione (GSH) levels in gills and liver tissue as oxidative stress biomarkers in the aquaculture fish species Nile tilapia (Oreochromis niloticus) after 24 (DBP‐24) and 96 (DBP‐96) h exposure. No differences were found between per cent HCT values in the 24 h exposure groups (P > 0.05). Response of antioxidant defence systems in liver and gill tissues of the fish were dependent on exposure duration and changed to a higher extent during 96 h. MDA levels in liver tissue increased in DBP treated fish in comparison to the control fish. However, the differences between the exposure and control groups were not significant (P > 0.05). A statistically significant decrease (P > 0.05) was recorded in gill MDA levels in the DBP‐96 group when compared to the control and DBP‐24 groups. The liver GSH levels were unchanged in the DBP treated fish. However, GSH levels were significantly lower in the gill tissue of the DBP‐96 group. Exposure to DBP caused several degenerative changes in the histology of gill and liver tissue. Gills displayed hyperaemia, epithelial lifting, oedema, talengiectasia, epithelial hyperplasia and fusion of secondary lamellae, whereas in liver several circulatory anomalies (hyperaemia, blood congestion and sinosoid dilatation) and vacuolization of hepatocytes were observed. Histopathological results demonstrated that the gills were more affected than the liver perhaps due to their direct contact with DBP. 相似文献
58.
应用组织病理学方法,对患"裂头病"黄颡鱼的肝脏、脾脏、肾脏、胃、肠道、脑进行观察。结果表明,各主要器官均有明显的组织病理学变化:肝中央静脉扩张,并有充血现象,肝细胞界限模糊不清,形状消失、变性,并发生肝实质组织溶解、消失。脾脏内有大量的含铁血黄素沉积。肾脏的实质细胞大量坏死,肾小球出现崩解、碎裂、溶解消失现象,近曲小管、远曲小管界限模糊,肾小管的上皮细胞肿胀,排列紊乱,管腔变窄、闭塞。胃上皮细胞排列紊乱,变性、坏死,胃黏膜大量脱落于胃腔中,胃腺细胞界限模糊、排列紊乱,胃腺管腔缩小,甚至消失。肠道上皮中有大量杯状细胞。脑组织出现弥散性出血,脑血管充血、出现大量的单核细胞。 相似文献
59.
Mycobacteriosis caused by Mycobacterium marinum in reared mullets: first evidence from Sardinia (Italy)
下载免费PDF全文
![点击此处可从《Journal of fish diseases》网站下载免费的PDF全文](/ch/ext_images/free.gif)
E Antuofermo A Pais M Polinas T Cubeddu M Righetti M A Sanna M Prearo 《Journal of fish diseases》2017,40(3):327-337
Mycobacterium marinum is a slow‐growing non‐tuberculous mycobacterium, and it is considered the most common aetiologic agent of mycobacteriosis in wild and cultured fish. The diagnosis is principally made by histology when positive Ziehl–Neelsen stain granulomas are detected. The aim of this study was to investigate the occurrence of mycobacteriosis in extensively cultured Mugilidae of two lagoons (Cabras and San Teodoro) from Sardinia by the use of histology, microbiology, PCR and DNA sequencing. Nine of 106 mullets examined were affected by mycobacteriosis, and the spleen was the most affected organ. The histology detected higher rate (100%) of infection in spleen than the culture and PCR (75% and 62.5%, respectively). The sequencing of hsp65 gene identified M. marinum as the primary cause of mycobacteriosis in the mullets examined. Mullets affected by mycobacteriosis were mainly fished in the San Teodoro lagoon characterized by critical environmental conditions. Histology remains the most common method in detecting fish affected by mycobacteriosis, and PCR‐based methods are essential for species identification. Our finding are worthy of attention because mycobacteriosis caused by M. marinum in reared mullets was evidenced for the first time in Sardinia, suggesting that this disease may be underestimated also in other cultured fish species. 相似文献
60.
First identification and characterization of Tenacibaculum dicentrarchi isolated from Chilean red conger eel (Genypterus chilensis,Guichenot 1848)
下载免费PDF全文
![点击此处可从《Journal of fish diseases》网站下载免费的PDF全文](/ch/ext_images/free.gif)