首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   235篇
  免费   8篇
林业   6篇
农学   11篇
  37篇
综合类   4篇
农作物   8篇
水产渔业   65篇
畜牧兽医   88篇
园艺   1篇
植物保护   23篇
  2022年   1篇
  2021年   6篇
  2020年   2篇
  2019年   5篇
  2018年   5篇
  2017年   2篇
  2016年   7篇
  2015年   3篇
  2014年   6篇
  2013年   33篇
  2012年   14篇
  2011年   13篇
  2010年   9篇
  2009年   9篇
  2008年   11篇
  2007年   15篇
  2006年   11篇
  2005年   14篇
  2004年   10篇
  2003年   12篇
  2002年   7篇
  2001年   14篇
  2000年   5篇
  1999年   6篇
  1997年   2篇
  1996年   1篇
  1994年   1篇
  1993年   2篇
  1992年   3篇
  1991年   2篇
  1990年   1篇
  1987年   1篇
  1986年   1篇
  1985年   2篇
  1983年   2篇
  1982年   1篇
  1980年   1篇
  1979年   1篇
  1974年   1篇
  1973年   1篇
排序方式: 共有243条查询结果,搜索用时 328 毫秒
31.
Medical records of dogs with colorectal polyps were retrospectively reviewed, and clinical presentation of inflammatory colorectal polyps in miniature dachshunds was evaluated. Of 33 dogs found to have colorectal polyps, miniature dachshunds were markedly over-represented with 16 dogs (48%), of which 12 (75%) were found to have inflammatory polyps. Multiple polyps localized between the rectum and the descending colon was the most common finding in miniature dachshunds with inflammatory polyps. Twenty dogs (80%) out of 25 miniature dachshunds with inflammatory colorectal polyps responded to immunosuppressive therapy using prednisolone and cyclosporine. The results of this study indicate that miniature dachshunds are predisposed to develop inflammatory colorectal multiple polyps, for which immunosuppressive therapy may be a treatment option.  相似文献   
32.
Endoscopic polypectomy and argon plasma coagulation (APC) were performed in a refractory case of inflammatory colorectal polyps in a 7-year-old male Miniature Dachshund. Colonoscopic examination revealed a large sessile polyp and multiple diffuse small polyps, localized to the descending colon and rectum. The case showed a poor therapeutic response to prednisolone and cyclosporine. Under anesthesia, piecemeal resections were performed by polypectomy. APC was carried out to cauterize the polyp remnants. After treatment, reduction of the lesions and the improvement in clinical signs were observed, without recurrence of lesions for at least 10 months. Endoscopic treatment by polypectomy and APC is suggested to be a therapeutic option for refractory cases of inflammatory colorectal polyps in dogs.  相似文献   
33.
Paddy fields converted into winter wheat fields in Hokkaido, Japan, receive extremely high snowfall, creating a risk of flood damage to crops in spring due to waterlogging of snowmelt runoff and poor drainage. Meanwhile, in June there is relatively little rainfall, and a lack of moisture inhibits winter wheat growth. Therefore, we developed a method involving a series of 30-cm-deep ditches in agricultural fields to be used for drainage during the flood-prone period and for furrow irrigation during the dry period using water drawn from the canals that feed the paddy fields. The ditches are called ‘hybrid ditches’ as they are able to perform both drainage and irrigation functions. In this study, we investigated the optimal construction timing and spacing for hybrid ditches. We also evaluated their ability to improve the drainage and irrigation of winter wheat. We found that the optimal timing for digging hybrid ditches is immediately after sowing, and the inter-ditch spacing for irrigation should be 15 m or less. The hybrid ditches promoted increased soil temperature and healthy development of wheat plants by improving drainage during the flood-prone period. In addition, water was successfully supplied via the hybrid ditches to irrigate the fields in June. Under experimental conditions in which rainfall was excluded, grain yield was 10% higher and percent protein content was more than 1% point greater in the irrigated plot compared with the non-irrigated plot. Grain yield was also observed to increase by 3–29% in demonstration tests conducted at local farms. From these results, we conclude that hybrid ditches are capable of improving the growth and yield of winter wheat by improving drainage and providing irrigation in converted paddy fields in Hokkaido.  相似文献   
34.
Human epigenetic studies suggest that consumption of seaweed prevents mammary cancer, which possibly is explained by iodine daily intake. In this study, we evaluated the efficacy of dietary intake of iodine‐enriched eggs on mammary tumor incidence caused by the expression of activated type ErbB2. Female transgenic mice were divided into three groups, and fed a basic diet, a diet supplemented with ordinary eggs, or with iodine‐enriched eggs. The number of mammary tumors greater than 5 mm in diameter was recorded in mice at 6 months of age. We report that the average number of mammary tumors per mouse was significantly lower in the iodine‐enriched egg‐added diet group than in either the basic diet or ordinary egg diet groups. These results indicate that iodine intake through livestock‐derived products can reduce the incidence of mammary cancers caused by the expression of activated type ErbB2.  相似文献   
35.
One of the difficulties to rear Anguilla japonica larvae is the frequent occurrence of notochord deformities. We tested the effect of salinity on the occurrence of the deformities, because we have been using 50 % diluted seawater (50 % SW) for glass eel production, on the basis of the fact that intermediate salinity saves energy due to lower cost for osmoregulation and contributes higher survival and growth rates. We reared 6-day-old larvae in 50 and 100 % SW for 85 days and observed their morphology. The occurrence rate of deformed larvae, including kyphosis and scoliosis, was significantly higher in 50 % SW (35.8 %) than in 100 % SW (25.4 %), while survival rate was significantly higher in 50 % SW (69.8 %) than in 100 % SW (32.3 %) and growth in 50 % SW (mean body depth: 7.9 ± 5.3 mm) was better than in 100 % SW (6.8 ± 4.6 mm). We speculate that the most of severely deformed larvae could not survive in the tougher condition of 100 % SW, showing the lower occurrence of deformed larvae. Eventually, the yield of normal larvae after 85 days rearing was 1.9-fold higher in 50 % SW than in 100 % SW, implying that the advantage of 50 % SW for rearing eel larvae outweighs the risk of deformities.  相似文献   
36.
Severe fruit rot of sweet pepper was found in Shimane, Hyogo, Chiba, Toyama, and Nagano prefectures, Japan from 2005 to 2011. Dark, sunken spots with concentric rings of orange conidial masses appeared on fruits. Pathogenic isolates from diseased fruits in the prefectures were identified as Colletotrichum scovillei. This species was added to the pathogens of sweet pepper anthracnose in Japan. The representative isolate was pathogenic to sweet pepper, tomato and chili pepper fruits, kidney bean pod, azuki bean, pea and strawberry leaves, but a caused no symptoms on cucumber or carrot in inoculation tests.  相似文献   
37.
A consumer questionnaire conducted with the purpose of ascertaining the acceptability of goat milk and related products in Japan was carried out on 345 guarantees of Nippon Veterinary and Life Science University in December 2006. 275 effective responses (79%) representing middle class urban households were returned. The results revealed that (1) 30% of respondents have experienced drinking goat milk and only 10% are aware of the current retail situation of goat milk and related products; (2) over 70% of goat milk drinkers raised goats by hand at some point in their past and their first experience drinking goat milk was in infancy; (3) those with experience in drinking goat milk expressed a vague evaluation and minimal understanding of drinking goat milk; (4) respondents who were inexperienced goat milk drinkers expressed a strong desire to taste and a weak desire to purchase goat milk; (5) respondents expressed low recognition regarding retailed goat milk products, but those who had already purchased goat milk products expressed a high evaluation and strong desire to purchase these products again; and (6) recognition of goat milk characteristics is low, but those with high recognition also rate goat milk highly. Goats are perceived as being 'mild and familiar.' It is necessary for those who manage goat husbandry to present goat milk and related product tasting opportunities to consumers. The key point is to make the functional differences between cow and goat milk clear and present the advantages of goat milk at the fore of this promotion. Goat milk should not be promoted merely as a drink that is similar to cow milk, but must be positioned as a functional drink or health food in order to expand the Japanese goat milk market.  相似文献   
38.

The spawning area of the Japanese eel is located at the southern part of the West Mariana Ridge in the western North Pacific, but their spawning events have not been observed. To further understand Japanese eel spawning ecology, an interdisciplinary research survey by the R/V NATSUSHIMA (NT14-09, 14 May–4 June 2014) was conducted to detect spawning sites based on the seamount, salinity front, new moon and third quadrant (spawning south of front, west of ridge) hypotheses. Attempts were made to film spawning events with underwater camera systems and to consider if eels might be detected in hydroacoustic observations. Although no Japanese eels or spawning events were video-recorded and no eel aggregations could be clearly identified acoustically, three eggs were collected at two stations in the third quadrant region at or just south of 13° N on 26 and 27 May. Three or four days later, newly hatched preleptocephali were collected at two stations far to the south, including 224 at a station > 160 km southwest of the egg catches, and a few preleptocephali were caught at two stations closer to the egg stations. The eggs and southern preleptocephali were from discrete spawning events, which indicated that at least two spawning sites occurred in May 2014.

  相似文献   
39.
Some anguillid spawning areas are known based on collections of small larvae, but recently for the Japanese eel Anguilla japonica, adult spawners have been caught in trawls and their eggs and preleptocephali collected. The spawning area of A. japonica is located along the western side of the West Mariana Ridge, but the natural spawning behavior of this species or that of any other anguillid species has never been observed. This study reports on the first effort to observe spawning aggregations of anguillid eels that was conducted by the R/V Yokosuka using the Shinkai 6500 submersible and a Deep-Tow camera system in the A. japonica spawning area in July 2012. The submersible was deployed mostly at 200–800 m during daytime and the Deep-Tow was deployed mostly at 130–250 m during nighttime, both in multiple oblique depth tracks along linear transects. Various fishes and invertebrates were seen in the pelagic environment during day and night, but no spawning aggregations were observed. One eel was briefly recorded by a Deep-Tow camera at 20:13 on 17 July (2 days before new moon) at a depth of 179 m. The eel was recorded for <1 s as it passed in front of the camera. Its anterior body and head shape were consistent with a male A. japonica, or possibly a Derichthys serpentinus eel, but not with other mesopelagic eels. Because the tail region of the eel was not visible, species identification was not possible.  相似文献   
40.
Anguilla luzonensis and A. huangi were each described in 2009 using eels obtained from northern Luzon Island. We examined the taxonomic status of these two groups of eels using morphological and molecular genetic characters. There were no significant differences in two vertebrae counts between eels of A. luzonensis and A. huangi. Mitochondrial 16S ribosomal RNA and cytochrome b genes sequences were obtained and compared among 28 specimens of A. luzonensis, the holotypes of A. luzonensis and A. huangi, and one specimen of the other 15 anguillid species. The specimens of A. luzonensis exhibited almost identical sequences, including the holotype, with only a few site differences, and the genetic difference between the holotypes of A. luzonensis and A. huangi was within the range of differences of specimens of A. luzonensis. The other anguillid species were genetically very different from A. luzonensis and A. huangi, although A. interioris is a closely related species. It is clear that A. luzonensis and A. huangi are the same species, and according to the principle of priority in zoological nomenclature, A. luzonensis Watanabe, Aoyama, and Tsukamoto, 2009 is the valid species name, and A. huangi Teng, Lin, and Tzeng, 2009 is a junior synonym of A. luzonensis.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号