全文获取类型
收费全文 | 6618篇 |
免费 | 363篇 |
国内免费 | 7篇 |
专业分类
林业 | 374篇 |
农学 | 154篇 |
基础科学 | 31篇 |
1098篇 | |
综合类 | 918篇 |
农作物 | 250篇 |
水产渔业 | 473篇 |
畜牧兽医 | 3108篇 |
园艺 | 169篇 |
植物保护 | 413篇 |
出版年
2023年 | 38篇 |
2022年 | 34篇 |
2021年 | 112篇 |
2020年 | 142篇 |
2019年 | 127篇 |
2018年 | 115篇 |
2017年 | 125篇 |
2016年 | 143篇 |
2015年 | 106篇 |
2014年 | 165篇 |
2013年 | 307篇 |
2012年 | 319篇 |
2011年 | 459篇 |
2010年 | 239篇 |
2009年 | 211篇 |
2008年 | 363篇 |
2007年 | 399篇 |
2006年 | 402篇 |
2005年 | 380篇 |
2004年 | 390篇 |
2003年 | 372篇 |
2002年 | 332篇 |
2001年 | 95篇 |
2000年 | 95篇 |
1999年 | 78篇 |
1998年 | 76篇 |
1997年 | 71篇 |
1996年 | 63篇 |
1995年 | 56篇 |
1994年 | 51篇 |
1993年 | 52篇 |
1992年 | 71篇 |
1991年 | 60篇 |
1990年 | 74篇 |
1989年 | 63篇 |
1988年 | 54篇 |
1987年 | 44篇 |
1986年 | 28篇 |
1985年 | 43篇 |
1984年 | 34篇 |
1983年 | 43篇 |
1982年 | 35篇 |
1981年 | 33篇 |
1980年 | 30篇 |
1979年 | 33篇 |
1978年 | 33篇 |
1977年 | 29篇 |
1975年 | 30篇 |
1974年 | 36篇 |
1967年 | 25篇 |
排序方式: 共有6988条查询结果,搜索用时 62 毫秒
41.
42.
43.
44.
İsmail Hakkı Nur William Pérez Horst Erich König 《Anatomia, histologia, embryologia》2021,50(3):658-667
This study aims to reveal the morphological properties of facial nerve and the middle ear in Van cats. Study material was composed of 6 female Van cats. Dissections were performed under a Zoom Stereo Microscope. There was no plexus buccalis in Van cats. The chorda tympani was observed to pass through an opening in the tympanic cavity, emerge through a small opening just behind the retroarticular process, and join the lingual nerve. A rounded anatomical formation with a size of 2.75 ± 0.3 mm was found to be located within the mastoid process of the temporal bone between the facial nerve and the auricular branch of the vagus nerve. The stapes nerve was not present. The geniculate ganglion was very prominent and about 1.00 mm high. The deep petrosal nerve was observed to emerge from the plexus tympanicus. The bulla tympanica was 18.96 ± 0.10 mm long, 13.03 ± 0.20 mm wide and 13.16 ± 0.20 mm high. After leaving the mandibular nerve, the n.tensoris tympani coursed caudally around the a.maxillaris, formed an ansa, entered the tympanic cavity through the canalis musculotubarius and reached an end in the m. tensor tympani. Due to the scarcity of studies on the middle ears of Van cats, it is thought that this study will fill a gap in the field of veterinary anatomy. 相似文献
45.
46.
47.
48.
49.
Dae Young Kim Michael M. Zinn Solomon O. Odemuyiwa William J. Mitchell Jr. Gayle C. Johnson 《Journal of veterinary diagnostic investigation》2021,33(1):167
Canine distemper virus (CDV) has long been recognized as a cause of myocarditis; however, cases of myocarditis caused by naturally acquired CDV infection have been reported only rarely in dogs. We describe here our retrospective study of naturally acquired systemic CDV infection in 4 dogs, 4–7 wk old, that had myocarditis, with myocardial necrosis and fibrosis. One of the 4 dogs had intracytoplasmic eosinophilic inclusion bodies in cardiomyocytes. Other lesions included bronchointerstitial pneumonia (4 of 4), necrotizing hepatitis (2 of 4), splenic lymphoid necrosis (2 of 4), encephalitis (1 of 3; brain was not submitted in 1 case), and necrotizing gastroenteritis (1 of 4). The presence of CDV in the heart was confirmed by immunohistochemistry in all 4 dogs. 相似文献
50.
INVITED REVIEW—IMAGE REGISTRATION IN VETERINARY RADIATION ONCOLOGY: INDICATIONS,IMPLICATIONS, AND FUTURE ADVANCES 下载免费PDF全文
Yang Feng Jessica Lawrence Kun Cheng Dean Montgomery Lisa Forrest Duncan B. Mclaren Stephen McLaughlin David J. Argyle William H. Nailon 《Veterinary radiology & ultrasound》2016,57(2):113-123
The field of veterinary radiation therapy (RT) has gained substantial momentum in recent decades with significant advances in conformal treatment planning, image‐guided radiation therapy (IGRT), and intensity‐modulated (IMRT) techniques. At the root of these advancements lie improvements in tumor imaging, image alignment (registration), target volume delineation, and identification of critical structures. Image registration has been widely used to combine information from multimodality images such as computerized tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET) to improve the accuracy of radiation delivery and reliably identify tumor‐bearing areas. Many different techniques have been applied in image registration. This review provides an overview of medical image registration in RT and its applications in veterinary oncology. A summary of the most commonly used approaches in human and veterinary medicine is presented along with their current use in IGRT and adaptive radiation therapy (ART). It is important to realize that registration does not guarantee that target volumes, such as the gross tumor volume (GTV), are correctly identified on the image being registered, as limitations unique to registration algorithms exist. Research involving novel registration frameworks for automatic segmentation of tumor volumes is ongoing and comparative oncology programs offer a unique opportunity to test the efficacy of proposed algorithms. 相似文献