全文获取类型
收费全文 | 385篇 |
免费 | 28篇 |
专业分类
林业 | 10篇 |
农学 | 28篇 |
基础科学 | 14篇 |
84篇 | |
综合类 | 22篇 |
农作物 | 52篇 |
水产渔业 | 43篇 |
畜牧兽医 | 128篇 |
园艺 | 7篇 |
植物保护 | 25篇 |
出版年
2023年 | 4篇 |
2022年 | 7篇 |
2021年 | 15篇 |
2020年 | 20篇 |
2019年 | 27篇 |
2018年 | 19篇 |
2017年 | 25篇 |
2016年 | 33篇 |
2015年 | 7篇 |
2014年 | 18篇 |
2013年 | 36篇 |
2012年 | 38篇 |
2011年 | 25篇 |
2010年 | 22篇 |
2009年 | 7篇 |
2008年 | 17篇 |
2007年 | 18篇 |
2006年 | 13篇 |
2005年 | 8篇 |
2004年 | 9篇 |
2003年 | 6篇 |
2002年 | 13篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 4篇 |
1992年 | 3篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有413条查询结果,搜索用时 15 毫秒
101.
102.
103.
Amir N Hamir Wilber W Clark Diane L Sutton Janice M Miller Mick J Stack Melanie J Chaplin Allen L Jenny 《Journal of veterinary diagnostic investigation》2002,14(5):444-445
Feline spongiform encephalopathy (FSE) is thought to have resulted from consumption of food contaminated with bovine spongiform encephalopathy and the latter is believed to result from the consumption of food contaminated with scrapie. However, no direct experimental documentation exists to indicate that the scrapie agent is capable of amplifying in cats, and, therefore, crossing the species barrier. During 1979, 6 cats ranging in age from 3.5 to 18 months were intracerebrally inoculated with sheep scrapie (inoculum G-639-PP) and were observed for an extended period. Inoculated cats did not develop neurologic disease, and microscopic lesions of spongiform encephalopathy were not evident. Immunohistochemistry and Western blot techniques failed to detect the abnormal form of prion protein (PrP(res)). These results indicate that the sheep scrapie agent (G-639-PP) used in this study was not capable of amplifying in cats and therefore was unable to cross the species barrier to produce FSE. 相似文献
104.
Mujtaba Yegany Gary Butcher Amir Nilipour Richard D.Miles Rohani Karegar 唐文渊 《国外畜牧学(猪与禽)》2002,(6):53-55
每年,仅仅肉鸡就合消耗一亿吨以上的成品饲料。饲料产品中一小部分受到污染就会使养鸡者和消费者付出高昂的代价。污染的饲料是不卫生的,不适合用于饲喂畜禽,因为这样的饲料合危害育禽的生产性能参数,比如健康、体重、饲料转化率、死亡率以及蛋鸡和种鸡的产蛋率。 相似文献
105.
The live, attenuated, temperature-sensitive Mycoplasma synoviae (MS) vaccine strain MS-H is used to control virulent MS infection in commercial chicken flocks. However, the safety of this vaccine and its potential to prevent disease in turkeys have not been investigated. In this study, MS-H was shown to colonize the upper respiratory system and to induce an antibody response in turkeys but, even at the maximum release dose, was not found to cause air sac, joint, or tracheal lesions typical of wild-type MS infection. Histopathologic examinations of the vaccinated turkeys after exposure to a virulent MS challenge revealed that administration of the vaccine by aerosol, but not eye drop, at the dose recommended for chickens protected the birds against microscopic lesions and colonization of the virulent MS in trachea. It is concluded that MS-H vaccine is safe for use in turkeys and, when used as aerosol at the dose recommended for commercial chickens, can protect turkeys against tracheal lesions caused by a wild-type MS strain. 相似文献
106.
Hamir AN Miller JM Yaeger MJ 《The Canadian veterinary journal. La revue veterinaire canadienne》2007,48(4):389-391
The brain of a ferret showing abnormal neurologic signs was evaluated by histopathologic, histochemical, immunohistochemical, and ultrastructural examinations. Extensive neuronal vacuolation was observed. Since the brain was negative for protease-resistant protein prion (PrP'"), it was concluded that this was not a case of transmissible spongiform encephalopathy. 相似文献
107.
Baradari AG Zeydi AE Espahbodi F Shahmohammadi S 《Pakistan journal of biological sciences: PJBS》2011,14(10):595-599
Chronic inflammation, as reflected by increased level of acute phase protein such as C-reactive Protein (CRP) is highly prevalent in hemodialysis patients. CRP is a strong predictor of overall and cardiovascular mortality and morbidity in hemodialysis patients. This research was conducted to determine the C-reactive Protein (CRP) levels and its correlation to demographic and clinical characteristics and Laboratory values in hemodialysis patients in Sari, Iran. In a cross sectional study, 147 hemodialysis patients were studied. Patients' demographic and clinical data were recorded and also serum CRP, Cholesterol, Albumin, Phosphorous, Calcium, Hemoglobin and Hematocrit levels were measured. Overall, the mean CRP concentration was 15.8 mg L(-1). With considering to the different cutoff point (5, 6.2, 10 mg L(-1)) for CRP level, 107 patients (72.8%) had CRP level >5 mg L(-1), 99 patients (67.3%) had CRP level > 6.2 mg L(-1) and 77 patients (52.4%) had CRP level >10 nmg L(-1). The CRP levels greater than 6.2, had a direct statistically significant correlation with duration of hemodialysis and phosphorus level (p = 0.01). Also, CRP levels above 10 mg L(-1) had a direct statistically significant correlation with age and phosphorus levels (p = 0.02). According to the prevalence of high CRP level and it's correlation with age, duration ofhemodialysis and phosphorus level in hemodialysis patients, CRP level should be screened in this group of patients routinely because of its prognostic importance. 相似文献
108.
In order to determine proper selection criteria for tuber yield in potato clones obtained from true potato seed (TPS) and
to evaluate relationships between tuber yield and its components, an investigation was conducted using the five check cultivars
Agria, Marfona, Draga, Agata, and Arinda, and 120 potato clones obtained from TPS. The study was conducted in an augmented
randomized complete block design with three replications. Yield and its components were recorded. Correlation coefficient
analysis showed that tuber yield had significant positive associations with number of tubers per plant, average weight per
tuber (tuber size), plant height, diameter of main stem, and number of main and secondary stems per plant, whereas its correlation
with tuber dry-matter concentration was significantly negative. Number of tubers per plant, tuber size, and plant height had
significant standardized partial regression coefficients with very small tolerance and large variance inflation factor (VIF)
values. These were considered as the first-order variables in sequential path analysis. 相似文献
109.
Plasmid transfer among isolates of Rhizobium leguminosarum bv. viciae in heavy metal contaminated soils from a long-term experiment in Braunschweig, Germany, was investigated under laboratory conditions. Three replicate samples each of four sterilized soils with total Zn contents of 54, 104, 208 and 340 mg kg−1 were inoculated with an equal number (1×105 cells g−1 soil) of seven different, well-characterized isolates of R. leguminosarum bv. viciae. Four of the isolates were from an uncontaminated control plot (total Zn 54 mg kg−1) and three were from a metal-contaminated plot (total Zn 340 mg kg−1).After 1 year the population size was between 106 and 107 g−1 soil, and remained at this level in all but the most contaminated soil. In the soil from the most contaminated plot no initial increase in rhizobial numbers was seen, and the population declined after 1 year to <30 cells g−1 soil after 4 years. One isolate originally from uncontaminated soil that had five large plasmids (no. 2-8-27) was the most abundant type re-isolated from all of the soils. Isolates originally from the metal-contaminated soils were only recovered in the most contaminated soil. After 1 year, four isolates with plasmid profiles distinct from those inoculated into the soils were recovered. One isolate in the control soil appeared to have lost a plasmid. Three isolates from heavy metal contaminated soils (one isolate from the soil with total Zn 208 mg kg−1 and two isolates from the soil with total Zn 340 mg kg−1) had all acquired one plasmid. Plasmid transfer was confirmed using the distinct ITS-RFLP types of the isolates and DNA hybridization using probes specific to the transferred plasmid. The transconjugant of 2-8-27 which had gained a plasmid was found in one replicate after 2 years of the most contaminated soil but comprised more than 50% of the isolates. A similar type appeared in a separate replicate of the most contaminated soil after 3 years and persisted in both of these soils until the final sampling after 4 years. After 2 years isolates were recovered from four of the soil replicates with the chromosomal type of 2-8-27 which appeared to have lost one plasmid, but these were not recovered subsequently.Isolate 2-8-27 was among the isolates most sensitive to Zn in laboratory assays, whereas isolate 7-13-1 showed greater zinc tolerance. Acquisition of the plasmid conferred enhanced Zn tolerance to the recipients, but transconjugant isolates were not as metal tolerant as 7-13-1, the putative donor. Laboratory matings between 2-8-27 and 7-13-1 in the presence of Zn resulted in the conjugal transfer of the same small plasmid from 7-13-1 to isolate 2-8-27 and the transconjugant had enhanced metal tolerance. Our results show that transfer of naturally-occurring plasmids among rhizobial strains is stimulated by increased metal concentrations in soil. We further demonstrate that the transfer of naturally-occurring plasmids is important in conferring enhanced tolerance to elevated zinc concentrations in rhizobia. 相似文献
110.
Farhadi-Tooli Sakineh Ghanbari Alireza Kermani Maryam Jafarkhani Zeinalabedini Mehrshad Bettoni Jean Carlos Naji Amir Mohammad Kazemi Nooshin 《European journal of plant pathology / European Foundation for Plant Pathology》2022,162(1):31-43
European Journal of Plant Pathology - Viral diseases affect quince plant productivity and fruit quality. This study evaluated the effectiveness of droplet-vitrification cryotherapy and... 相似文献