全文获取类型
收费全文 | 207篇 |
免费 | 13篇 |
专业分类
林业 | 5篇 |
农学 | 3篇 |
38篇 | |
综合类 | 77篇 |
农作物 | 11篇 |
水产渔业 | 1篇 |
畜牧兽医 | 73篇 |
园艺 | 2篇 |
植物保护 | 10篇 |
出版年
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 3篇 |
2017年 | 3篇 |
2016年 | 6篇 |
2015年 | 3篇 |
2014年 | 7篇 |
2013年 | 10篇 |
2012年 | 3篇 |
2010年 | 4篇 |
2009年 | 2篇 |
2008年 | 3篇 |
2007年 | 3篇 |
2005年 | 3篇 |
2004年 | 8篇 |
2003年 | 4篇 |
2002年 | 9篇 |
2001年 | 5篇 |
2000年 | 3篇 |
1999年 | 10篇 |
1998年 | 7篇 |
1996年 | 2篇 |
1995年 | 4篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 11篇 |
1988年 | 4篇 |
1987年 | 8篇 |
1986年 | 4篇 |
1985年 | 10篇 |
1984年 | 5篇 |
1983年 | 2篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1978年 | 2篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 4篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1971年 | 5篇 |
1970年 | 3篇 |
1969年 | 4篇 |
1967年 | 4篇 |
1966年 | 2篇 |
1955年 | 2篇 |
1929年 | 2篇 |
1916年 | 1篇 |
排序方式: 共有220条查询结果,搜索用时 15 毫秒
61.
Heavy infestation of calves, lambs and kids with the cat flea Ctenocephalides felis felis (Bouché, 1835), accompanied by severe anaemia and mortality, is described. Lambs and kids were affected more severely than calves. Flea infestation was more widespread in summer and autumn than in winter and spring. The clinical findings are discussed in the light of the pertinent literature. 相似文献
62.
I Takashima N Hashimoto T Watanabe L Rosen 《Nippon juigaku zasshi. The Japanese journal of veterinary science》1989,51(5):947-953
A study was conducted during 1985 and 1986 to evaluate the roles of mosquito species as possible vectors of Japanese encephalitis (JE) virus in Hokkaido. The number of Culex tritaeniorhynchus was very low among the four pig farms where outbreaks of abortion caused by JE virus were observed in swine populations. At one farm near Sapporo, only one Cx. tritaeniorhynchus was found among a total of 510 mosquitoes collected during the survey period from July to October 1985, even when JE virus activity among sentinel pigs was revealed by seroconversion. At another farm in the south, no individuals of this mosquito species were found among 987 mosquitoes collected at the time of the outbreaks of abortion. Cx. pipiens pallens, Anopheles species, Aedes vexans nipponii, and Ae. japonicus were predominant over Cx. tritaeniorhynchus. Cx. tritaeniorhynchus, almost a solve vector species of JE virus in the southern part of Japan, is probably not a vector of the virus in Hokkaido. The collected mosquitoes (2,332 from 1985 and 1,403 from 1986) were processed for virus isolation but no JE virus was isolated. More extensive field studies are necessary to provide further information on the role of mosquito species other than Cx. tritaeniorhynchus in the transmission of JE virus in the northern limits of its range including Hokkaido. 相似文献
63.
Myiasis caused by Wohlfahrtia magnifica (Schiner, 1862) in the Arabian camel (Camelus dromedarius) in the Peninsula of Sinai 总被引:1,自引:0,他引:1
A Hadani B Ben Yaakov S Rosen 《Revue d'élevage et de médecine vétérinaire des pays tropicaux》1989,42(1):33-38
Massive myiasis caused by Wohlfahrtia magnifica (Schiner, 1862) in camels in the Southern Mountainous zone of the Peninsula of Sinai is described. Wohlfahrtiosis seemed intimately related to the climatic and ecological conditions of the area, particularly altitude, precipitation, pasture, rodents and ticks. The clinical features resembled those described in sheep in Israel and in camels elsewhere. Treatment with diazinon and synergized pyrethrum in pine oil proved effective. 相似文献
64.
LF Crocomo F Ariu L Bogliolo D Bebbere S Ledda SD Bicudo 《Reproduction in domestic animals》2016,51(2):276-281
The efficiency of in vitro sheep embryo production is still low compared to that observed in vivo and in other species. In this context, meiotic inhibition strategies emerged as a promising alternative to improve this biotechnology. So, this study aimed to evaluate, for the first time, the effects of roscovitine on in vitro maturation of sheep oocytes and their subsequent embryo development. For this, cumulus–oocyte complexes (COCs) were cultured for 6 h in the presence (Rosco) or absence (Control) of 75 μm roscovitine and, subsequently, in vitro matured (IVM) for 18 h with gonadotropins. At 0 (Immature), 6 and 24 h of culture, the nuclear status of oocytes was evaluated by Hoechst staining. Embryo cleavage and blastocyst formation were recorded 30 h after in vitro fertilization and on day 7 of culture, respectively. Blastocyst quality was evaluated by differential staining. At 6 h, the GV rate in the Rosco treatment (93.8%) was similar to that observed in the Immature oocytes (94.9%) and significantly higher compared to Control (41.3%). After IVM for 18 h, a high and similar proportion of oocytes from Rosco (93.6%) and Control (88.4%) reached the MII stage. In both treatments, approximately 70% of oocytes cleaved and 50% of them developed up to blastocyst. The mean percentage of blastocyst cells, embryoblast, trophoblast and pyknosis did also not differ between Control and Rosco. In conclusion, roscovitine, at the studied experimental conditions, was efficient to reversibly inhibit the meiosis of adult sheep oocytes without detrimental effect on development and quality of the in vitro produced embryos. 相似文献
65.
66.
Recent measurements of small aerosol particles in the stratosphere over Laramie, Wyoming, indicate low-concentration background conditions. A comparison of measurements made some 20 years ago with the present background concentration reveals the possibility of an increase of 9 percent per year. Since the aerosol particles are predominantly sulfuric acid droplets which form in the stratosphere from tropospheric sulfur-containing gases, such an increase may be related to man-made sulfur emissions. 相似文献
67.
The motility outcomes of boar semen frozen with newly developed freezing techniques using a new unique freezing technology (UFT) compared with traditional liquid nitrogen methodology were investigated with the intent of improving current fertility outcomes using semen. The UFT is an electronically controlled cooling chamber that houses an organic fluid bath that can be maintained at temperatures below 0 degrees C without solidifying to freeze samples. Four ejaculates from four different boars were collected for this trial. Samples were handled consistently during the pre- and post-freeze processing. From each ejaculate, samples were separated into eight cryopreservation treatment groups, six UFT variations and two control liquid nitrogen groups, immediately before freezing, in replicates of two. After the initial cryopreservation was complete, all samples were stored in liquid nitrogen for at least 48 h. Post-thaw motilities and original motility return percentages were assessed on a random, individual-sample basis. After the initial evaluations, samples from two boars were recollected and frozen using the UFT for breeding purposes. Four sows were bred with the UFT frozen semen to confirm fertility capability. When assessing the individual UFT techniques, all of six UFT techniques had improved post-thaw motilities. However, treatments F (micro = 29%, return micro = 37%) and J (micro = 27%, return micro = 34%) showed the highest statistical improvement for post-thaw (p < 0.05) and original motility percent returns (p < 0.05) when compared with either the control cryo-tube (micro = 15%, return micro = 19%) or straw groups (micro = 12%, return micro = 16%). The UFT semen had a 50% conception rate, with an average of seven piglets from the sows that farrowed. Our preliminary data suggest a higher motility return with a slower pre-freeze phase below the freezing point before the acceleration to liquid nitrogen temperatures. The preliminary data suggest that the UFT could be utilized as a potential cryopreservation option for boar semen. 相似文献
68.
69.
A method was developed for mass rearing the Florida wax scale (FWS),Ceroplasta floridensis Comstock — an important pest of citrus and other fruit trees in the Mediterranean basin — for production of natural enemies. The effect of host plant species, intensity of illumination and scale insect density on survival and size of the FWS was studied.Myrtus communis was found to be the most efficient host plant, and the required intensity of illumination was 200 µmol m-2s-1(with a photoperiod of 12L: 12D). Under these conditions, a density of 500 scale insects per plant could be achieved without reducing the size of the FWS below that required for the development of natural enemies. 相似文献
70.
Climate change,human impacts,and the resilience of coral reefs 总被引:11,自引:0,他引:11
Hughes TP Baird AH Bellwood DR Card M Connolly SR Folke C Grosberg R Hoegh-Guldberg O Jackson JB Kleypas J Lough JM Marshall P Nyström M Palumbi SR Pandolfi JM Rosen B Roughgarden J 《Science (New York, N.Y.)》2003,301(5635):929-933
The diversity, frequency, and scale of human impacts on coral reefs are increasing to the extent that reefs are threatened globally. Projected increases in carbon dioxide and temperature over the next 50 years exceed the conditions under which coral reefs have flourished over the past half-million years. However, reefs will change rather than disappear entirely, with some species already showing far greater tolerance to climate change and coral bleaching than others. International integration of management strategies that support reef resilience need to be vigorously implemented, and complemented by strong policy decisions to reduce the rate of global warming. 相似文献