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   343篇
  免费   31篇
林业   18篇
农学   4篇
  54篇
综合类   10篇
农作物   25篇
水产渔业   51篇
畜牧兽医   185篇
园艺   7篇
植物保护   20篇
  2024年   1篇
  2023年   2篇
  2022年   6篇
  2021年   13篇
  2020年   15篇
  2019年   32篇
  2018年   18篇
  2017年   25篇
  2016年   20篇
  2015年   14篇
  2014年   12篇
  2013年   26篇
  2012年   28篇
  2011年   33篇
  2010年   11篇
  2009年   18篇
  2008年   6篇
  2007年   21篇
  2006年   14篇
  2005年   8篇
  2004年   9篇
  2003年   5篇
  2002年   6篇
  2001年   8篇
  2000年   5篇
  1999年   3篇
  1997年   2篇
  1996年   2篇
  1995年   1篇
  1992年   4篇
  1991年   2篇
  1990年   2篇
  1984年   1篇
  1983年   1篇
排序方式: 共有374条查询结果,搜索用时 15 毫秒
91.
92.
Rabies is an endemic disease in Brazil, where it is considered a serious public health problem. Although the number of human and dog‐transmitted cases has declined in recent decades, rabies in wildlife has emerged considerably. Among the sylvatic animals, wild canids have been considered important hosts of the rabies virus. We performed a retrospective study of reported cases of rabies in wild canids and human victims in Ceará state (Northeast Brazil) during 2003 to 2013. Information was provided by governmental laboratories involved in rabies detection and by the Ministry of Health. From January 2003 to December 2013, a total of 11 931 animal samples were examined for rabies. Positivity were detected in 438 samples (3.67%), of which 229 (52.28%) were domestic animals, 105 (23.97%) wild canids and 104 (23.74%) other wild animals (bats, marmosets and raccoons). Approximately 33% of wild canids surveyed (n = 317) were positive for rabies. During the studied period, a total of 1923 attacks on humans by wild canids were registered. Males (n = 1405) were more affected than females (n = 520; 72.98% versus 27.01%), and the median age of all cases was 36.5 years. Injuries to individuals up to 19 years old corresponded to approximately 30% (n = 565) of all cases. Most of the victims lived in rural areas (72.46%; n = 1395), and the majority showed bites (81.13%; n = 1677) or scratches (12.23%; n = 253). Injuries were considered profound (52.1%; n = 1003), superficial (40.91; n = 788) or multiple with severe laceration (6.98%; n = 134). Only 1300 (67.53%) victims were enrolled for the complete rabies post‐exposure prophylaxis scheme. Data from the present study confirm that wild canids are important hosts of rabies virus in northeastern Brazil and jeopardize rabies control in this area. Local authorities should focus their efforts in education of health professionals. In addition, strategies should be formulated to preserve wildlife.  相似文献   
93.
94.
The aim of the study was to verify the influence of selenomethionine (SM) supplementation on performance, carcass yield, characteristics of meat quality and Se tissue deposition of finishing pigs. A total of 128 hybrid pigs with an average weight of 76 kg were distributed in randomized blocks according to body weight in eight treatments and eight replicates. The experimental treatments were two Se levels from sodium selenite‐SS (0.3 and 0.6 ppm), four Se levels from SM (0.3, 0.4, 0.5 and 0.6 ppm) and two combinations of SS with SM (SS 0.15 + SM 0.15 ppm and SS 0.3 + SM 0.3 ppm) providing 0.3 and 0.6 ppm Se in the diet respectively. The feeds were based on corn and soya bean meal. After 30 days on test, were analysed the performance indices and the pigs were slaughtered at commercial slaughterhouse. The cold carcass yield, the physicochemical characteristics of the loin meat and the Se content in muscle and liver were evaluated. There was no significant difference in performance indices (p > .05); however, there was a linear effect on the increase in pig carcass yield by increasing SM (p < .05). The use of SM solely or combined with SS provided higher Se deposition in muscle compared to SS (p < .05). The highest Se deposition in muscle occurred for SM at 0.4 ppm (p < .05). The SS provided higher Se deposition in liver (p < .05). The SM presented best results for meat quality compared to other sources (p < .05). The level of 0.4 ppm Se promoted the best results for the indices of yellow, luminosity, cooking loss and pH (p < .05). The use of SM at any level promotes higher oxidation stability of pig meat (p < .05). The supplementation of SM at a level of 0.4 ppm promotes better physicochemical characteristics and higher Se deposition on swine meat.  相似文献   
95.
The aim of this study was to evaluate the effect of increasing concentrate supplementation levels on the intake, nutrient digestibility, and performance of crossbred steers during the dry period of the year. The experiment was developed on Princesa do Mateiro farm, in the municipality of Ribeirão do Largo, located in the southwest region of Bahia State, Brazil. Forty uncastrated male crossbred (½ Holstein-Zebu) steers with an average body weight (BW) of 232.55?±?24.97 kg were distributed into four treatments in a completely randomized design with ten replicates. The animals were managed in an experimental area formed by Brachiaria brizantha cv. Marandu, in an intermittent grazing system. Treatments consisted of the following supplementation levels: 0.2% BW, with 60% crude protein (CP); 0.3% BW, with 40% CP; 0.4% BW, with 30% CP; and 0.5% BW, with 24% CP. The intakes of forage dry matter in kg/day and %BW and neutral detergent fiber corrected for ash and protein (NDFap) in %BW decreased linearly, whereas the intake of non-fibrous carbohydrates corrected for ash and protein in kg/day and average daily gain increased linearly. Therefore, the use of supplementation at 0.5% BW (24% crude protein) to provide gains of up to 0.500 kg/day is recommended for grazing steers during the post-weaning period in the dry season of the year.  相似文献   
96.
Changes in physiological parameters that are induced by acute exercise on a treadmill in healthy military dogs have not been thoroughly investigated, especially with regard to age. This study investigated the effects of acute exercise on a treadmill on cardiovascular function, biochemical parameters and gastric antral motility in military dogs. Thermography was used to assess variations in superficial hindlimb muscle temperature. Nine healthy dogs were distributed into three groups according to their age (Group I: 25 ± 7 months; Group II: 51 ± 12 months; Group III: 95 ± 10 months) and sequentially subjected to running exercise on a treadmill for 12 min (3.2 km/h at 0° incline for 4 min, 6.4 km/h at 0° incline for 4 min and 6.4 km/h at 10° incline for 4 min). Heart rate, systolic and diastolic arterial pressure (DAP), gastric motility, haematocrit and biochemical analyses were performed at rest and after each session of treadmill exercise. Infrared thermographic images of muscles in the pelvic member were taken. Exercise decreased DAP in Group I, increased systolic arterial pressure in Groups II and III and increased mean arterial pressure in Group III (all p < 0.05). After the exercise protocol, plasma creatine kinase and aspartate aminotransferase levels increased only in Group I (p < 0.05). Exercise increased heart rate and decreased the gastric motility of a solid meal at 180 min in all groups (all p < 0.05). Exercise also elevated temperature in the femoral biceps muscles in Group I compared with the older dogs. The results indicate that acute exercise decreased gastric motility in dogs, regardless of age, and caused more pronounced cardiovascular changes in older dogs than in younger dogs. Acute exercise also altered biochemical parameters and superficial hindlimb muscle temperature in younger military dogs.  相似文献   
97.
Drought can drastically reduce cowpea [Vigna unguiculata (L.) Walp.] biomass and grain yield. The application of plant growth‐promoting rhizobacteria and arbuscular mycorrhizal fungi can confer resistance to plants and reduce the effects of environmental stresses, including drought. Seed coating is a technique which allows the application of minor amounts of microbial inocula. Main effects of the factors inoculation and water regime showed that: severe or moderate water deficit had a general negative impact on cowpea plants; total biomass production, seed weight and seed yield were enhanced in plants inoculated with P. putida; inoculation of R. irregularis significantly increased nitrogen (N) and phosphorus (P) shoot concentrations; and R. irregularis enhanced both chlorophyll b and carotenoids contents, particularly under severe water deficit. Plants inoculated with P. putida + R. irregularis had an increase in shoot P concentration of 85% and 57%, under moderate and severe water deficit, respectively. Singly inoculated P. putida improved potassium shoot concentration by 25% under moderate water deficit. Overall, in terms of agricultural productivity the inoculation of P. putida under water deficit might be promising. Seed coating has the potential to be used as a large‐scale delivery system of beneficial microbial inoculants.  相似文献   
98.
The adverse effects from using currently available drugs for the treatment of leishmaniasis have motivated the search for new therapeutical agents. The aim of this work was to evaluate the effect of imidocarb and levamisole on the treatment of BALB/c mice experimentally infected by Leishmania (Leishmania) amazonensis. BALB/c mice were infected with 10(6) promastigotes of L. (L.) amazonensis (IFLA/BR/67/PH8) and, starting on day 51, mice were treated subcutaneously with imidocarb (IMD, 34 mg/kg), imidocarb plus levamisole (IMD+LVS, 34 and 12 mg/kg, respectively), only levamisole (LVS, 12 mg/kg) or without treatment (control). Lesion size and swelling were weekly monitored for 10 weeks after the beginning of the treatment. On day 121 post-infection, serum levels of specific IgG from infected mice were evaluated, as well as histopathological and morphometric alterations in the footpad, lymph nodes and spleen of these animals. The data obtained in this study demonstrated that, when compared to controls, mice treated with IMD had lower levels of IgG anti-L. (L.) amazonensis (34.45%), smaller vacuolar area in macrophages (3.75%), lower number of megakaryocytes in spleen (63.19%) and lower parasite burden in the footpad (30.2%). Thus, the evaluated parameters suggest the use of imidocarb as a potential drug in the treatment of tegumentary leishmaniasis.  相似文献   
99.
Sporotrichosis is a mycosis caused by Sporothrix schenckii. The most affected animal is the cat; it has played an important role in the zoonotic transmission of this disease, especially in Rio de Janeiro, Brazil, since 1998. In order to evaluate the treatment of feline sporotrichosis with potassium iodide, an observational cohort was conducted in 48 cats with sporotrichosis at Instituto de Pesquisa Clínica Evandro Chagas, Fiocruz. All cats received potassium iodide capsules, 2.5 mg/kg to 20 mg/kg q24h. The cure rate was 47.9%, treatment failure was 37.5%, treatment abandonment was 10.4% and death was 4.2%. Clinical adverse effects were observed in 52.1% of the cases. Thirteen cats had a mild increase in hepatic transaminase levels during the treatment, six of them presented clinical signs suggestive of hepatotoxicity. Compared to previous studies with itraconazole and iodide in saturated solution, potassium iodide capsules are an alternative for feline sporotrichosis treatment.  相似文献   
100.
The effects of a low dose of equine purified FSH (eFSH) on incidence of multiple ovulations and embryo recovery rate in mares were studied. During the physiological breeding season in Brazil (19°45′45′S), 14 Mangalarga Marchador donor mares were used in a crossover study and another 25 mares of the same breed, between 3 years and 12 years of age were used as recipients for the embryo transfers. Donors were monitored during two consecutive oestrus cycles, an untreated control cycle followed by a treated cycle, when eFSH was administered. In both cycles, after an embryo collection attempt on day 8 post‐ovulation all mares received 7.5 mg dinoprost and had their two largest follicles tracked daily by ultrasonography until the period of ovulation. Mares were inseminated every 48 h with extended fresh semen from a single stallion after the identification of a 35‐mm follicle until the period of ovulation. Ovulations were induced by intravenous administration of 2.500 IU of human chorionic gonadotropin, upon detection of a 35‐ to 40‐mm follicle. In the treated cycle, 5 mg eFSH was given intramuscularly once a day, from day 8 post previous ovulation until at least one follicle reached 35 mm in diameter. Embryo flushes were performed on day 8 of dioestrus (day 0 = ovulation). Treatment with eFSH resulted in higher (p < 0.05) ovulation rate and incidence of multiple ovulations compared to the control (1.6 vs 1.0 and 50% vs 0%, respectively – one mare had triple ovulation). However, embryo recovery rates in the control and treated cycles were similar (0.8 and 1.0, respectively; p > 0.05). Pregnancy rates in the recipient mares following embryo transfer were similar for the control and eFSH cycles (11/11 and 10/14, respectively). Additional studies are necessary in order to develop a low‐dose protocol for the use of eFSH that brings a more consistent contribution to the efficiency of commercial equine embryo transfer programs.  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