全文获取类型
收费全文 | 439篇 |
免费 | 13篇 |
专业分类
林业 | 1篇 |
农学 | 10篇 |
基础科学 | 8篇 |
17篇 | |
综合类 | 208篇 |
农作物 | 9篇 |
水产渔业 | 11篇 |
畜牧兽医 | 167篇 |
园艺 | 6篇 |
植物保护 | 15篇 |
出版年
2021年 | 4篇 |
2019年 | 6篇 |
2018年 | 3篇 |
2017年 | 7篇 |
2015年 | 5篇 |
2014年 | 4篇 |
2013年 | 8篇 |
2012年 | 10篇 |
2011年 | 15篇 |
2010年 | 5篇 |
2009年 | 3篇 |
2008年 | 15篇 |
2007年 | 15篇 |
2006年 | 13篇 |
2005年 | 11篇 |
2004年 | 6篇 |
2003年 | 8篇 |
2002年 | 5篇 |
2001年 | 11篇 |
2000年 | 6篇 |
1999年 | 8篇 |
1998年 | 7篇 |
1997年 | 6篇 |
1996年 | 7篇 |
1995年 | 4篇 |
1994年 | 6篇 |
1992年 | 10篇 |
1991年 | 6篇 |
1990年 | 5篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 4篇 |
1984年 | 5篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 8篇 |
1977年 | 23篇 |
1976年 | 25篇 |
1975年 | 17篇 |
1974年 | 26篇 |
1973年 | 22篇 |
1972年 | 30篇 |
1971年 | 27篇 |
1970年 | 7篇 |
1963年 | 2篇 |
1955年 | 2篇 |
排序方式: 共有452条查询结果,搜索用时 218 毫秒
101.
102.
103.
Gawain Hammond Toby Gemmill Dominic Mellor Martin Sullivan 《Veterinary radiology & ultrasound》2008,49(1):20-25
Teleradiology involves the creation of a radiographic image that is then transmitted electronically. It has been shown that low-cost teleradiology has a high level of agreement when comparing the original radiograph to the digital image. However, there has been little investigation of the effect of digitization on the score allocated by a grading scheme. Radiographs of 60 canine elbows were selected, each in three projections (mediolateral flexed, mediolateral neutral, craniocaudal). Each radiograph was photographed at 3 megapixel (3 M) and 6 megapixel (6 M) resolution using a digital camera. The images were placed in groups (radiographs, 3 M and 6 M) and randomized. Each elbow was independently graded by a radiologist and an orthopedic surgeon using the BVA elbow scoring scheme, with the different image sets interpreted separately. Intra and interobserver agreement was compared using a kappa analysis. The radiologist had substantial intraobserver agreement for repeated grading of radiographs, and moderate agreement for the other intraobserver tests (3 M vs. radiographs, 6 M vs. radiographs, 3 vs. 6 M). The surgeon had moderate to substantial agreement for the intraobserver tests. There was reduced interobserver agreement for all image groups. These results suggest that low-cost teleradiology may only allow moderate accuracy when used for grading schemes, and this may affect its use for breed scoring schemes. However, there appears to be an inherent subjectivity present in the elbow-grading scheme, seen in both intra and interobserver analysis. Therefore, further study of teleradiology using a different scoring model (e.g., hip dysplasia) may be indicated. 相似文献
104.
Annalisa M. Hernandez Graham E. A. Bilbrough Dennis B. DeNicola Celine Myrick Suzanne Edwards Jeremy M. Hammond Alex N. Myers Johanna C. Heseltine Karen Russell Marco Giraldi Mary B. Nabity 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2019,33(1):167-177
105.
梨韧皮部特异表达启动子AtSUC2驱动下的GUS基因的转化和表达 总被引:2,自引:0,他引:2
以 ‘Old Home’ 梨无菌苗叶片为外植体, 利用根癌农杆菌介导将专一在韧皮部表达启动子AtSUC2 驱动下的GUS 基因转入 ‘Old Home’中。筛选出了‘Old Home’ 梨叶片高效遗传转化的最佳条件:农杆菌和外植体在液体培养基上共培比在固体培养基上共培转化率提高5倍。 PCR分析和Southern 杂交鉴定表明GUS 基因已整合到转基因植株的基因组中,组织化学检测和Western 杂交鉴定证明了GUS 基因在转基因植株韧皮部中的表达。 相似文献
106.
IMAGING DIAGNOSIS—MAGNETIC RESONANCE IMAGING OF DIFFUSE LEPTOMENINGEAL OLIGODENDROGLIOMATOSIS IN A DOG WITH “DURAL TAIL SIGN”
下载免费PDF全文
![点击此处可从《Veterinary radiology & ultrasound》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Monika Anna Lobacz Fabienne Serra Gawain Hammond Anna Oevermann Allison C. Haley 《Veterinary radiology & ultrasound》2018,59(1):E1-E6
A case of diffuse leptomeningeal oligodendrogliomatosis affecting the brain and spinal cord of a dog is presented. A 7.5‐year old, male neutered Staffordshire bull terrier presented for evaluation of a chronic history of tetraparesis and seizures, with a multifocal neuroanatomical localization was determined. Extra‐axial intradural lesions with an atypical presentation of a dural tail sign were seen on MRI. Histologically, the lesions were consistent with leptomeningeal oligodendrogliomatosis. To the authors’ knowledge, a dural tail sign has not previously been reported as an MRI characteristic of diffuse leptomeningeal oligodendrogliomatosis in dogs. 相似文献
107.
Mycoplasma synoviae (Ms) is an important pathogen of poultry, causing economic losses to this industry. Early and reliable diagnosis is a key to controlling the spread of this organism. In this study, a polymerase chain reaction with one primer based on the intergenic spacer region (ISR) was validated for detection of Ms. The ISR primer was paired with a general primer from within the 23S rRNA gene. The PCR primers were tested with the 22 other recognised avian Mycoplasma species to check the specificity and with 21 field isolates of Ms from various hosts and countries, and with several swab samples. The PCR appeared to be specific and sensitive. Four different sample preparation methods were compared for use in this PCR, and the amplification protocol was compared with three others, confirming the comparative sensitivity of the new PCR. 相似文献
108.
109.
Braunschweig H Dewhurst RD Hammond K Mies J Radacki K Vargas A 《Science (New York, N.Y.)》2012,336(6087):1420-1422
Homoatomic triple bonds between main-group elements have been restricted to alkynes, dinitrogen, and a handful of reactive compounds featuring trans-bent heavier elements of groups 13 and 14. Previous attempts to prepare a compound with a boron-boron triple bond that is stable at ambient temperature have been unsuccessful, despite numerous computational studies predicting their viability. We found that reduction of a bis(N-heterocyclic carbene)-stabilized tetrabromodiborane with either two or four equivalents of sodium naphthalenide, a one-electron reducing agent, yields isolable diborene and diboryne compounds. Crystallographic and spectroscopic characterization confirm that the latter is a halide-free linear system containing a boron-boron triple bond. 相似文献
110.
King AM Posthumus J Hammond G Sullivan M 《Veterinary journal (London, England : 1997)》2012,193(2):493-497
Evaluation of the tympanic bulla (TB) in cases of otitis media in the rabbit can be a diagnostic challenge, although a feature often associated with the condition is the accumulation of fluid or material within the TB. Randomly selected TB from 40 rabbit cadavers were filled with a water-based, water-soluble jelly lubricant. A dorsoventral radiograph and single computed tomography (CT) slice were taken followed by an ultrasound (US) examination. Image interpretation was performed by blinded operators. The content of each TB was determined (fluid or gas) using each technique and the cadavers were frozen and sectioned for confirmation. CT was the most accurate diagnostic method, but US produced better results than radiography. Given the advantages of US over the other imaging techniques, the results suggest that further work is warranted to determine US applications in the evaluation of the rabbit TB and clinical cases of otitis media in this species. 相似文献