全文获取类型
收费全文 | 99篇 |
免费 | 6篇 |
专业分类
林业 | 12篇 |
农学 | 1篇 |
23篇 | |
综合类 | 13篇 |
农作物 | 5篇 |
水产渔业 | 6篇 |
畜牧兽医 | 42篇 |
园艺 | 2篇 |
植物保护 | 1篇 |
出版年
2022年 | 1篇 |
2021年 | 2篇 |
2019年 | 7篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 4篇 |
2015年 | 1篇 |
2014年 | 6篇 |
2013年 | 4篇 |
2012年 | 4篇 |
2011年 | 11篇 |
2010年 | 4篇 |
2009年 | 4篇 |
2008年 | 14篇 |
2007年 | 6篇 |
2006年 | 4篇 |
2005年 | 5篇 |
2004年 | 5篇 |
2003年 | 3篇 |
2002年 | 1篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1972年 | 1篇 |
1967年 | 1篇 |
1963年 | 1篇 |
1945年 | 1篇 |
排序方式: 共有105条查询结果,搜索用时 15 毫秒
21.
The antiviral activity of two phenolic compounds, hispolon and hispidin, isolated from the fruit bodies of the basidiomycete Inonotus hispidus as well as of some extracts prepared from fruit bodies and mycelial cultures of this fungus was investigated in allantois on the shell-test system. Ethanolic extracts, hispidin and hispolon showed considerable antiviral activity against influenza viruses type A and B. 相似文献
22.
Kristine Maraldo Leon van der Linden Teis N. Mikkelsen Martin Holmstrup 《Soil biology & biochemistry》2010,42(11):1958-1966
The potential impacts of interactions of multiple climate change factors in soil ecosystems have received little attention. Most studies have addressed effects of single factors such as increased temperature or atmospheric CO2 but little is known about how such environmental factors will interact. In the present study we investigate the effects of in situ exposure to elevated atmospheric CO2 concentration, increased temperatures and prolonged drought episodes on field communities of Enchytraeidae (Oligochaeta) in a dry heathland (Brandbjerg, Denmark). Increased CO2 had a positive effect on enchytraeid biomass, whereas drought significantly reduced it. Elevated temperature did not result in any detectable effects. No interactions between the three factors were observed. Interestingly, the positive effect of increased CO2 and the negative effect of drought were cancelled out when applied in combination. Thus, in the combined drought and CO2 treatment, and when additionally combined with increased temperature, the total biomass of enchytraeids was similar to those in the ambient plots. The positive effect of increased CO2 seemed to be influenced by season, as the response was most pronounced during summer, and less so in autumn. The impact of the drought was more consistent, with enchytraeids reduced at all sampling occasions. Moreover, the negative effect of drought seemed to depend on the inter-annual variability of precipitation. The year with a dry summer and autumn (2006) showed a stronger impact of drought on the enchytraeids, compared to the year with a wet summer and autumn (2007). Our study emphasises the importance of multi-factorial experimental design as a means to investigate effects of climatic changes. 相似文献
23.
Native starch granules of 11 selected cultivars (potato, waxy potato, sweet potato, normal maize, high‐amylose maize, waxy maize, wheat, normal barley, high‐amylose barley, waxy barley, and rice) were treated with a calcium chloride solution (4M) for surface gelatinization. The surface‐gelatinized starch granules were investigated using light microscopy and scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). In general, those starches with larger granule sizes required longer treatment time to complete the gelatinization. The salt solution treatment of starch was monitored by light microscopy and stopped when the outer layer of the granule was gelatinized. The surface gelatinized starch granules were studied using scanning electron microscopy. On the basis of the gelatinization pattern from calcium chloride treatments, the starches could be divided into three groups: 1) starches with evenly gelatinized granule surface, such as normal potato, waxy potato, sweet potato, maize, and high‐amylose maize; 2) starches with salt gelatinization concentrated on specific sites of the granule (i.e., equatorial groove), such as wheat, barley, and high‐amylose barley; and 3) starches that, after surface gelatinization, can no longer be separated to individual granules for SEM studies, such as waxy barley, waxy maize, and normal rice. The morphology of the surface gelatinized starch resembled that of enzyme‐hydrolyzed starch granules. 相似文献
24.
se Helen Garseth Torfinn Moldal Siri Kristine Gsnes Monika Jankowska Hjortaas Vegard Pedersen Sollien Anne‐Gerd Gjevre 《Journal of fish diseases》2019,42(3):391-396
In 2017, a PCR‐based survey for Piscine orthoreovirus‐3 (PRV‐3) was conducted in wild anadromous and non‐anadromous salmonids in Norway. In seatrout (anadromous Salmo trutta L.), the virus was present in 16.6% of the fish and in 15 of 21 investigated rivers. Four of 221 (1.8%) Atlantic salmon (Salmo salar L.) from three of 15 rivers were also PCR‐positive, with Ct‐values indicating low amounts of viral RNA. All anadromous Arctic char (Salvelinus alpinus L.) were PCR‐negative. Neither non‐anadromous trout (brown trout) nor landlocked salmon were PRV‐3 positive. Altogether, these findings suggest that in Norway PRV‐3 is more prevalent in the marine environment. In contrast, PRV‐3 is present in areas with intensive inland farming in continental Europe. PRV‐3 genome sequences from Norwegian seatrout grouped together with sequences from rainbow trout (Oncorhynchus mykiss Walbaum) in Norway and Coho salmon (Oncorhynchus kisutch Walbaum) in Chile. At present, the origin of the virus remains unknown. Nevertheless, the study highlights the value of safeguarding native fish by upholding natural and artificial barriers that hinder introduction and spread, on a local or national scale, of alien fish species and their pathogens. Accordingly, further investigations of freshwater reservoirs and interactions with farmed salmonids are warranted. 相似文献
25.
Kristine M Smith Paul Calle Bonnie L Raphael Stephanie James Robert Moore Denise McAloose Eric Baitchman 《Journal of zoo and wildlife medicine》2006,37(1):44-48
Medical records of three male and three female callitrichids of four species (Leontopithecus chrysopygus, Leontopithecus rosalia, Callithrix argentata argentata, Callithrix kuhlii) diagnosed with cholelithiasis were reviewed. Ages of affected animals at the time of diagnosis ranged from 2-14 yr. Definitive antemortem diagnosis of cholelithiasis was made in four of the six cases. Chronic weight loss, lethargy, and weakness were seen in all cases. Chronic intermittent diarrhea was seen in three cases. Icterus and abnormal gait were each present in two of the animals. Hematologic and serum biochemical abnormalities included leukocytosis in five cases, elevated bilirubin (direct and indirect) in four cases, and anemia in four cases. Radiographic evidence of choleliths was observed in three cases. Surgical removal of choleliths was successfully performed on two animals. Full necropsies were performed on all cases, and choleliths were believed to contribute to morbidity in all cases. However, inflammatory bowel disease was determined to be the primary cause of weight loss and mortality in at least three animals. All choleliths analyzed were pigment stones, two being primarily composed of cystine. 相似文献
26.
Poirier VJ Burgess KE Adams WM Vail DM 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2004,18(4):536-539
The purpose of this study was to evaluate short-term adverse effects and determine a safe dosage for vinorelbine (Navelbine)--a new semisynthetic vinca alkaloid--in dogs with malignant tumors. Nineteen dogs were treated with vinorelbine as a 5-minute IV infusion every 7 days at starting dosages ranging from 10 to 20 mg/m2. The median number of treatments per dog was 7 (range, 1-11). The maximum tolerated dosage varied between 15 and 18 mg/m2, and a starting dosage of 15 mg/m2 is recommended. Neutropenia was the dose-limiting toxicity. Although efficacy was a secondary endpoint of this dosage-finding study, 2 dogs with metastatic bronchoalveolar carcinoma experienced a partial response for an overall response rate of 12.5% in 16 dogs with gross measurable disease. Three dogs with microscopic disease were treated (incompletely excised bronchoalveolar carcinoma or lymph node metastatic disease). Two died of pulmonary metastatic disease 113 and 196 days posttreatment, and 1 is still alive after at least 730 days. The well-tolerated toxicity profile and clinical activity observed in dogs with bronchoalveolar carcinoma warrants further investigation. 相似文献
27.
Stacey Halse Stefano Pizzirani Nicola M. A. Parry Kristine E. Burgess 《Veterinary ophthalmology》2014,17(3):221-227
A 3‐year‐old Marwari mare was presented for evaluation of an irregular, reddish mass protruding from behind the right third eyelid. The mass appeared to arise at the ventral limbal area, involved the perilimbal bulbar conjunctiva and widely extended into corneal tissue. No other ocular or systemic abnormalities were detected at the time of presentation. The mass was surgically removed by lamellar keratectomy, with defocused CO2 laser used as adjunctive therapy to treat the surgical exposed area and its surroundings. Histopathologic evaluation showed sheets of densely packed, well‐differentiated neoplastic mast cells separated by fibrovascular connective tissue. Nuclear staining for Ki‐67 was performed, and an average of 370 cells were positive per 1000 counted cells. Two months postoperatively, the surgical site was filled with flat fibrovascular and pigmented tissue, while the surrounding cornea was transparent with no superficial vascularization around the fibrotic scar. Thirty‐two months after treatment, no recurrence of the neoplasia was reported. 相似文献
28.
29.
Bizzarro M Ulfbeck D Trinquier A Thrane K Connelly JN Meyer BS 《Science (New York, N.Y.)》2007,316(5828):1178-1181
High-precision 60Fe-60Ni isotope data show that most meteorites originating from differentiated planetesimals that accreted within 1 million years of the solar system's formation have 60Ni/58Ni ratios that are approximately 25 parts per million lower than samples from Earth, Mars, and chondrite parent bodies. This difference indicates that the oldest solar system planetesimals formed in the absence of 60Fe. Evidence for live 60Fe in younger objects suggests that 60Fe was injected into the protoplanetary disk approximately 1 million years after solar system formation, when 26Al was already homogeneously distributed. Decoupling the first appearance of 26Al and 60Fe constrains the environment where the Sun's formation could have taken place, indicating that it occurred in a dense stellar cluster in association with numerous massive stars. 相似文献
30.
Chang JT Palanivel VR Kinjyo I Schambach F Intlekofer AM Banerjee A Longworth SA Vinup KE Mrass P Oliaro J Killeen N Orange JS Russell SM Weninger W Reiner SL 《Science (New York, N.Y.)》2007,315(5819):1687-1691
A hallmark of mammalian immunity is the heterogeneity of cell fate that exists among pathogen-experienced lymphocytes. We show that a dividing T lymphocyte initially responding to a microbe exhibits unequal partitioning of proteins that mediate signaling, cell fate specification, and asymmetric cell division. Asymmetric segregation of determinants appears to be coordinated by prolonged interaction between the T cell and its antigen-presenting cell before division. Additionally, the first two daughter T cells displayed phenotypic and functional indicators of being differentially fated toward effector and memory lineages. These results suggest a mechanism by which a single lymphocyte can apportion diverse cell fates necessary for adaptive immunity. 相似文献