全文获取类型
收费全文 | 223篇 |
免费 | 11篇 |
专业分类
林业 | 9篇 |
农学 | 8篇 |
基础科学 | 1篇 |
48篇 | |
综合类 | 38篇 |
农作物 | 19篇 |
水产渔业 | 19篇 |
畜牧兽医 | 67篇 |
园艺 | 3篇 |
植物保护 | 22篇 |
出版年
2023年 | 1篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 3篇 |
2015年 | 5篇 |
2014年 | 9篇 |
2013年 | 13篇 |
2012年 | 17篇 |
2011年 | 17篇 |
2010年 | 14篇 |
2009年 | 13篇 |
2008年 | 20篇 |
2007年 | 6篇 |
2006年 | 10篇 |
2005年 | 12篇 |
2004年 | 16篇 |
2003年 | 11篇 |
2002年 | 11篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1995年 | 6篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1984年 | 1篇 |
1980年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1955年 | 1篇 |
1951年 | 1篇 |
排序方式: 共有234条查询结果,搜索用时 15 毫秒
51.
Effect of body condition score and reuse of progesterone‐releasing intravaginal devices on conception rate following timed artificial insemination in Nelore cows 下载免费PDF全文
LL Pereira AP Ferreira WG Vale LR Serique KAL Neves AC Morini BM Monteiro AHH Minervino 《Reproduction in domestic animals》2018,53(3):624-628
This study had the aim of investigating the efficiency of timed artificial insemination (TAI) through the progesterone‐releasing intravaginal device (PRID), used in new condition and for the second and third times in Nelore cows. The effects of device reuse and body condition score (BCS) on the conception rate (CR) were evaluated in 1,122 multiparous Nelore cows (mean BCS of 2.7 ± 0.4), which were randomly distributed into three groups that received new (n = 330), once (n = 439) and twice used (n = 353) PRID. Among the 1,122 females that underwent TAI, 573 became pregnant, thus representing an overall CR of 51.06%. Cows with BCS between 2.75 and 4.0 had greater (p < .0001) CR (69.75%) than cows with BSC of 2.0–2.5 (32.98%). It was observed that the CR through using PRID was 60.00%, 51.71% and 41.93% for new, once and twice used PRID, respectively, with difference between all groups (p < .0001). Under tropical conditions, animals with BCS greater than 2.5 had a higher CR, and the CR decreased proportionally with the number of times that the PRID had been used. 相似文献
52.
Sensory stimuli reach the brain via the thalamocortical projection, a group of axons thought to be among the most powerful in the neocortex. Surprisingly, these axons account for only approximately 15% of synapses onto cortical neurons. The thalamocortical pathway might thus achieve its effectiveness via high-efficacy thalamocortical synapses or via amplification within cortical layer 4. In rat somatosensory cortex, we measured in vivo the excitatory postsynaptic potential evoked by a single synaptic connection and found that thalamocortical synapses have low efficacy. Convergent inputs, however, are both numerous and synchronous, and intracortical amplification is not required. Our results suggest a mechanism of cortical activation by which thalamic input alone can drive cortex. 相似文献
53.
Bert Devriendt M��lanie Gallois Frank Verdonck Yann Wache Diane Bimczok Isabelle P. Oswald Bruno M. Goddeeris Eric Cox 《Veterinary research》2009,40(4)
Consumption of food or feed contaminated with fumonisin B1 (FB1), a mycotoxin produced by Fusarium verticillioides, can lead to disease in humans and animals. The present study was conducted to examine the effect of FB1 intake on the intestinal immune system. Piglets were used as a target and as a model species for humans since their gastro-intestinal tract is very similar. The animals were orally exposed to a low dose of FB1 (1 mg/kg body weight FB1) for 10 days which did not result in clinical signs. However, when compared to non-exposed animals, FB1-exposed animals showed a longer shedding of F4+ enterotoxigenic Escherichia coli (ETEC) following infection and a lower induction of the antigen-specific immune response following oral immunization. Further analyses to elucidate the mechanisms behind these observations revealed a reduced intestinal expression of IL-12p40, an impaired function of intestinal antigen presenting cells (APC), with decreased upregulation of Major Histocompatibility Complex Class II molecule (MHC-II) and reduced T cell stimulatory capacity upon stimulation. Taken together, these results indicate an FB1-mediated reduction of in vivo APC maturation. 相似文献
54.
FRM Soto WG Viana GCB Mucciolo FYM Hosomi CI Vannucchi CP Mazzei AR Eyherabide C De Fátima Lúcio RA Dias SS De Azevedo 《Reproduction in domestic animals》2009,44(6):927-931
The aim of this research was to evaluate the efficacy of zinc gluconate associated with dimethyl sulphoxide (DMSO) for chemical neutering in canine males. Fifteen sexually mature male dogs were divided in two groups, named control and treated. An injection was administered to both testicles, at a concentration of 26.2 mg zinc gluconate per ml and 0.5% DMSO in the treated group (11 dogs). The control group was given injections of saline solution (four dogs). Clinical examination and blood collection for a haemogram were done both before and after drug injection. There were 12 spermograms performed to analyse sperm motility, sperm vigour, ejaculate volume, testicle size, pathology and sperm concentrations. Libido was also measured. An ultrasound examination and histopathology were performed at the end of the experiment. Dogs’ libido after chemical injection was reduced by over 50%. The spermogram analysis showed final mean results of 14.54% for sperm motility, 0.72 of sperm vigour and 37 150 per million spermatozoa per millilitre, values considered below the necessary levels at which fertilization can occur. Ultrasound and histopathology analyses of testicles for the treated group revealed more intense injuries when compared with the control group, with compromised testicular parenchyma and a decrease of germ cell number leading to total atrophy, indicating that the treatment reduced the fertilizing potential of male dogs, promoting a possible subfertile status. 相似文献
55.
Noseda B Dewulf J Goethals J Ragaert P Van Bree I Pauwels D Van Langenhove H Devlieghere F 《Journal of agricultural and food chemistry》2010,58(22):11864-11869
The total volatile basic nitrogen fraction (TVB-N) is often used as a quality parameter in the fish industry to assess spoilage. This parameter often leads to discussions between producers and retailers when it comes to defining clear limits of acceptability for modified atmosphere (MA) packed fish and fishery products. Suggested product limits (mg N/100 g fish) do not always correlate with the presence of off-odors. Gray shrimp are an economic valuable, very perishable niche product, where the TVB-N fraction plays an important role considering its shelf life. This research focuses on the effect of a shrimp matrix and its pH on the volatilization of these formed bases, revealing the relationship between concentrations in the fishery product and the concentrations of these bases present in the headspace of the packed product. Especially, the pH of the product, which is lowered when fishery products are packed under a carbon dioxide enriched atmosphere, appeared to have an immense effect on the volatilization of these bases. The effect of the fish matrix itself is established by means of calculated equilibration constants (dimensionless) being 2.13×10(-4)±0.38×10(-4) for trimethylamine, 6.34×10(-5)±1.71×10(-5) for dimethylamine, and 2.58×10(-5)±0.49×10(-5) for ammonia. Comparison of these constants with the equilibration constants of an aqueous solution indicated the retention of these bases in the product. This article provides not only the important insights for the interpretation of TVB-N values in modified atmosphere packaged gray shrimp but also the methodology to extend these findings to other fish and fishery products. 相似文献
56.
Brusselman E Beck B Pollet S Temmerman F Spanoghe P Moens M Nuyttens D 《Pest management science》2012,68(3):444-453
BACKGROUND: The present study compared entomopathogenic nematode delivery at the base of savoy cabbage and cauliflower, at the lower side of savoy cabbage and cauliflower leaves and in leek stems and the ground deposition using a five‐nozzle spray boom equipped with an ISO 08 flat fan, an air induction flat fan and Twinjet spray nozzles. Additionally, an air support system and a row application system were evaluated. RESULTS: Approximately 40% of the applied nematodes did not reach the foot of the cabbage plants. The use of an air support system or a row application system improved nematode deposition at the savoy cabbage base. Relative nematode deposition on the lower side of savoy cabbage leaves was 27.20%, while only 2.64% of the applied nematodes reached the lower side of cauliflower leaves. After spraying leek with a standard boom, a low relative nematode deposition (26.64%) was measured in the leek stem. Nozzle type affected the distribution of nematodes in droplet spots. CONCLUSION: Nozzle type has a minor effect on the number of entomopathogenic nematodes delivered on difficult‐to‐reach targets. The use of modified spray application techniques directing the spray to the target site are necessary to increase the chances of contact of entomopathogenic nematodes with their target. Copyright © 2011 Society of Chemical Industry 相似文献
57.
Benjamín Berdiales Juan J. Bernal Elisa Sáez Bert Woudt Francisco Beitia Emilio Rodríguez-Cerezo 《European journal of plant pathology / European Foundation for Plant Pathology》1999,105(2):211-215
The relative occurrence in Spain of two whitefly transmitted closteroviruses causing similar yellowing diseases in melon and cucumber greenhouse crops was studied. Based on a RT-PCR assay, a 1994–1997 survey of Spanish greenhouses showed that the recently described Bemisia tabaci-transmitted cucurbit yellow stunting disorder virus (CYSDV) has displaced the Trialeurodes vaporariorum-transmitted beet pseudo-yellows virus (BPYV), a virus that was present in the area since the late 1970s. The CYSDV transmission rates by each of the two biotypes of B. tabaci present in Spain were compared. The results showed that the ubiquitous B biotype and the resident Q biotype (found in Spain and Portugal) were able to transmit CYSDV with similar efficiency. 相似文献
58.
Urlings B 《Tijdschrift voor diergeneeskunde》2005,130(9):281-283
59.
Bert A Shelley 《Veterinary Clinics of North America: Small Animal Practice》2002,32(3):621-37, vii
The skin of the perianal region is very thin and sensitive. The carbon dioxide laser is a very effective tool for removing tumors and treating conditions of this area. It offers a "no touch" method of treatment for conditions of the perianal region. There is less bleeding, less pain, less swelling with the use of the carbon dioxide laser. The carbon dioxide laser is an effective tool for excising perianal tumors, rectal tumors, performing anal sacculectomies and treating perianal fistulas. 相似文献
60.