全文获取类型
收费全文 | 817篇 |
免费 | 51篇 |
专业分类
林业 | 116篇 |
农学 | 35篇 |
基础科学 | 4篇 |
122篇 | |
综合类 | 28篇 |
农作物 | 68篇 |
水产渔业 | 85篇 |
畜牧兽医 | 331篇 |
园艺 | 11篇 |
植物保护 | 68篇 |
出版年
2023年 | 6篇 |
2022年 | 15篇 |
2021年 | 33篇 |
2020年 | 45篇 |
2019年 | 38篇 |
2018年 | 41篇 |
2017年 | 34篇 |
2016年 | 43篇 |
2015年 | 23篇 |
2014年 | 34篇 |
2013年 | 57篇 |
2012年 | 62篇 |
2011年 | 45篇 |
2010年 | 29篇 |
2009年 | 21篇 |
2008年 | 46篇 |
2007年 | 39篇 |
2006年 | 36篇 |
2005年 | 24篇 |
2004年 | 19篇 |
2003年 | 11篇 |
2002年 | 18篇 |
2001年 | 17篇 |
2000年 | 13篇 |
1999年 | 7篇 |
1998年 | 4篇 |
1997年 | 11篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 4篇 |
1992年 | 12篇 |
1991年 | 8篇 |
1990年 | 5篇 |
1989年 | 7篇 |
1988年 | 5篇 |
1987年 | 3篇 |
1986年 | 5篇 |
1985年 | 5篇 |
1983年 | 4篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1970年 | 2篇 |
1969年 | 2篇 |
1968年 | 4篇 |
排序方式: 共有868条查询结果,搜索用时 15 毫秒
91.
A survey of helminth parasites in stray dogs was carried out in the Zaria area. Out of 180 dogs examined 65.6 per cent (118/180) were found positive for Ancylostoma caninum, while Toxocara canis and Trichuris vulpis were detected in 41.1 per cent (74/180) and 13.9 per cent (25/180) respectively. Other helminth parasites found Taenia ovis 35 per cent (63/180) Taenia hydatigena 67.8 per cent (122/180), Echinococcus granulosus 0.006 per cent (1/180) and Dipylidium caninum 97.8 per cent (176/180). 相似文献
92.
Infection of dogs with Echinococcus gramulosus is recorded for the first time in Kaduna State. Observations on 330 dogs from different suburbs revealed an incidence of 1.2 per cent. Of slaughtered stock examined, hydatid cyst infections were found in sheep (7.1 per cent), goats (18.4 per cent), cattle (1.5 per cent), camels (70.9 per cent) and pigs (5 per cent). 相似文献
93.
94.
The contact toxicity of indoxacarb, abamectin, endosulfan, insecticide soap, S-kinoprene and dimethoate to Orius insidiosus (Say) and Aphidius colemani Viereck were studied in the laboratory. These beneficials are often used in the greenhouses to manage various insect pests. Indoxacarb is slow acting and therefore, to estimate lethal dosages, observations should be continued for several days until data stabilize. Seven days after treatment, the LC50 was 0.119 g AI litre(-1) for O insidiosus adults and 0.019 g AI litre(-1) for A colemani. At that time, the recommended field concentration was 0.479 times the LC50 for O insidiosus adults and three times the LC50 for A colemani. In contrast, indoxacarb had no adverse effect on the reproductive capacity of wasps surviving a treatment or the developing wasps in the aphid mummy. Among the other insecticides S-kinoprene was the most innocuous while dimethoate was the most toxic to the two beneficials. The other insecticides had overlapping toxicities. 相似文献
95.
Seno T Izumisawa Y Nishimura I Maehara S Kushiro T Umar MA Wakaiki S Yamashita K Kotani T 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2004,66(3):315-318
Screw and laser (SL) column by making screw threads and forming small holes using laser irradiation on the base metal and conventional beads coating (BC) columns were embedded into the shaft of canine femurs, and compared the implant fixation to the host bone. The interfacial strength in SL columns was almost equivalent as BC columns, and bone-column contact rate was higher than BC columns significantly at twelve weeks after implantation. The newly devised SL surface had almost equivalent bone fixation strength comparable to the conventional BC surface. Also, this surface should provide a useful porous surface for use in artificial joints since there is no risk of surface structure detachment. 相似文献
96.
Abou-Elezz Fouad Mohammed K Sarmiento-Franco L Santos-Ricalde R Solorio-Sanchez JF 《Tropical animal health and production》2012,44(5):1035-1040
This study aimed to evaluate the potential of Moringa oleifera fresh leaves (MOL) as feed supplement on the performance and egg quality of Rhode Island Red (RIR) hens under the tropical
conditions of Yucatan, Mexico. Forty-eight RIR hens were allocated in 12 floor pen replicates each with four birds. Thereafter,
the replicates were divided into three groups which were corresponded to ad libitum feed (control), ad libitum feed supplemented
with MOL T1 (AL + MOL) and restricted feed amount (20% lower than control) with MOL T2 (RCD + MOL), respectively. T1 (AL +
MOL) had higher egg laying rate (71.4% versus 66.6%), higher daily egg mass production (45.4 versus 41.9 g/day), lower feed
intake (121.3 versus 127.5 g/day) and better feed conversion ratio (2.8 versus 3.2 g feed:g egg) versus control. T2 / (RCD
+ MOL) had lower values of body weight, egg laying rate, egg weight and egg mass, and recorded better feed conversion ratio
than the control group. The control group recorded a higher percentage of pecked eggs versus T1 and T2 (6.5% versus 1.2% and
2.0 %). Similar intake of MOL (3.1 and 3.4 g DM/day) was recorded in T1 (AL + MOL) and T2 (RCD + MOL). Yolk color was improved
significantly in T1 (AL + MOL) than both control and T2 (RCD + MOL), while T2 (RCD + MOL) had eggs with lower yolk and higher
albumen percentages than the other two ad libitum groups. The results suggest that MOL could be used successfully as sustainable
tropical feed resource for RIR hens. 相似文献
97.
Okab AB Ayoub MA Samara EM Abdoun KA Al-Haidary AA Koriem AA Hassan AA 《Tropical animal health and production》2012,44(7):1623-1629
Twenty-five intact Barki lambs with mean body weight of 24.81 ± 0.16?kg were used to investigate the effect of including in the diet sugar beet pulp (SBP) treated biologically with Trichoderma reesei or chemically with urea 4 % on nutrients digestibility, growth performance, nitrogen (N) utilization, and hematological and biochemical parameters. Two experiments were conducted. In the growth experiment, five lambs were randomly assigned to one of five dietary treatments. Lambs were offered isonitrogenous and isoenergetic concentrate feed mixture containing on dry matter basis 0 % SBP (D0), 50 % SBP (D1), 50 % SBP treated with 4 % urea (D2), 50 % SBP treated with T. reesei (D3), and 25 % SPB treated with 4 % urea plus 25 % SPB treated with T. reesei (D4). In the metabolism experiment, five rams were used in a 5?×?5 Latin square design and housed in metabolism crates for 21?days. The present study showed that inclusion of SBP at the level of 50 % (D1) negatively affected diet digestibility coefficients of crude protein, crude fiber, and ether extract, in addition to average daily gain, feed conversion, and N utilization. However, treatment of SBP with urea (D2), T. reesei (D3), or the combination (D4) of both had improved (P?0.05) these parameters with superiority of D3. Despite the significant differences in the tested hematological and biochemical parameters of lambs fed on biologically or chemically treated SBP diets, their levels remained within the physiological ranges which could indicate that treated SBP did not have any adverse effect on lambs' health. 相似文献
98.
Sukhumavasi W Bellosa ML Lucio-Forster A Liotta JL Lee AC Pornmingmas P Chungpivat S Mohammed HO Lorentzen L Dubey JP Bowman DD 《Veterinary parasitology》2012,188(1-2):25-30
The seroprevalence of Toxoplasma gondii, Dirofilaria immitis (heartworm), feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) infections was examined using serum or plasma samples from 746 pet cats collected between May and July 2009 from clinics and hospitals located in and around Bangkok, Thailand. The samples were tested for heartworm, FIV, and FeLV using a commercial ELISA. Of the 746 samples, 4.6% (34/746) were positive for heartworm antigen, 24.5% (183/746) had circulating FeLV antigen, and 20.1% (150/746) had antibodies against FIV. In addition, the first 348 submitted samples were tested for T. gondii antibodies using a modified agglutination test (MAT, cut off 1:25); 10.1% (35/348) were seropositive. Of the 348 cats sampled for all four pathogens, 11, 10, and 1 were positive for T. gondii antibodies and FIV antibodies, FeLV antigen, or D. immitis antigen, respectively. Of the 35 T. gondii-seropositive cats, 42.9% (15/35) were co-infected with at least one of the other three pathogens. The presence of antibodies to FIV was significantly associated with both age and gender, while FeLV antigen presence was only associated with age. In the case of FIV, males were twice as likely to be infected as females, and cats over 10 years of age were 13.5 times more likely to be infected than cats less than 1 year of age. FeLV antigen was more common in younger cats, with cats over 10 years of age being 10 times less likely to be FeLV positive than cats under 1 year of age. This is the first survey for these four pathogens affecting feline health in Thailand. 相似文献
99.
A longitudinal herd-level study was carried out to determine the cumulative incidence of Giardia duodenalis infections in dairy cattle in the New York City Watershed. We also sought to assess the changes in infection pattern of animals diagnosed as shedding Giardia over time, determine risk factors that may be associated with G. duodenalis infections, and identify potentially zoonotic infections. A total of 2109 fecal samples were randomly collected from dairy cattle at 34 farms in the New York City Watershed on a seasonal basis. A total of 504 Giardia-positive samples were identified by zinc sulfate flotation. The overall cumulative incidence of G. duodenalis based on flotation results was 23.9% with 73.8% of all infections occurring in animals under 180 days of age (372/504). The intensity of infection ranged from 2 to 563,200 cysts/gram of feces. Cattle shedding Cryptosporidium spp. oocysts were twice as likely to shed G. duodenalis cysts in comparison to the animals that did not shed oocysts (1.81 95% CI 1.26-2.60 p=0.0012). In the multivariate analysis, only the age of the animal and the presence of dogs on the farm were significantly associated with the likelihood of shedding G. duodenalis. DNA was extracted from positive samples and analyzed by polymerase chain reaction (PCR) of the beta-giardin and triosephosphate isomerase genes of Giardia spp. 304 samples were analyzed by PCR of which 131 were sequenced. 22.1% of sequenced samples were identified as assemblage A and 77.9% were identified as assemblage E. Interestingly, 100% of specimens identified as assemblage A were from calves under 84 days of age indicating that younger cattle are important reservoirs for potentially zoonotic assemblages of G. duodenalis. 相似文献
100.
Dkhil MA Abdel-Maksoud MA Al-Quraishy S Abdel-Baki AA Wunderlich F 《Veterinary parasitology》2012,186(3-4):222-228
Eimeria coecicola causes intestinal coccidiosis in rabbits and, thereby, enormous economic losses in rabbit farms. Here, we investigate the final target site of E. coecicola, the appendix of rabbits, at the level of gene expression. Rabbits, orally infected with E. coecicola, begin to shed parasitic oocysts with their feces on day 5 p.i., and approximately 1.1 million oocysts are maximally shedded on day 7 p.i. At maximal shedding, the appendix has increased in size by about 2-3-folds and reveals increased hemorrhage which is associated with increases in nitrite/nitrate, malondialdehyde and catalase activity and a decrease in glutathione. Agilent 2-color oligo whole rabbit genome microarray, in combination with quantitative real-time PCR, detects 45 and 36 genes whose expression is more than 2-fold up- and down-regulated, respectively, by E. coecicola infection on day 7 p.i. The most dramatic increase by approximately 50-fold reveals the mRNA of the pro- and anti-inflammatory pleiotropic cytokine interleukin 6 (IL-6), whereas the largest decrease by approximately 13-fold is detected for mRNAs encoding for DBP, SULT3A1, CRP and glutathione-S transferase. Also, there are up- and down-regulations in the expression of genes encoding diverse regions of antibodies. Our data suggest that IL-6 plays a central role in the infection of the appendix of rabbits by E. coecicola, presumably involved in both pathological injuries, host defences and healing processes. 相似文献