全文获取类型
收费全文 | 5305篇 |
免费 | 308篇 |
国内免费 | 4篇 |
专业分类
林业 | 269篇 |
农学 | 244篇 |
基础科学 | 9篇 |
1002篇 | |
综合类 | 609篇 |
农作物 | 587篇 |
水产渔业 | 424篇 |
畜牧兽医 | 2068篇 |
园艺 | 74篇 |
植物保护 | 331篇 |
出版年
2023年 | 28篇 |
2022年 | 89篇 |
2021年 | 116篇 |
2020年 | 97篇 |
2019年 | 107篇 |
2018年 | 137篇 |
2017年 | 160篇 |
2016年 | 184篇 |
2015年 | 164篇 |
2014年 | 199篇 |
2013年 | 284篇 |
2012年 | 350篇 |
2011年 | 418篇 |
2010年 | 223篇 |
2009年 | 220篇 |
2008年 | 314篇 |
2007年 | 301篇 |
2006年 | 270篇 |
2005年 | 248篇 |
2004年 | 232篇 |
2003年 | 189篇 |
2002年 | 203篇 |
2001年 | 144篇 |
2000年 | 119篇 |
1999年 | 77篇 |
1998年 | 32篇 |
1997年 | 18篇 |
1996年 | 20篇 |
1995年 | 21篇 |
1993年 | 21篇 |
1992年 | 28篇 |
1991年 | 27篇 |
1990年 | 33篇 |
1989年 | 37篇 |
1988年 | 31篇 |
1987年 | 40篇 |
1986年 | 18篇 |
1985年 | 32篇 |
1984年 | 23篇 |
1983年 | 27篇 |
1981年 | 19篇 |
1980年 | 15篇 |
1978年 | 21篇 |
1977年 | 19篇 |
1976年 | 28篇 |
1975年 | 14篇 |
1974年 | 20篇 |
1973年 | 22篇 |
1972年 | 22篇 |
1971年 | 15篇 |
排序方式: 共有5617条查询结果,搜索用时 0 毫秒
21.
Productive performance of weanling piglets was improved by administration of a mixture of bacteriophages,targeted to control Coliforms and Clostridium spp. shedding in a challenging environment 下载免费PDF全文
A. R. Hosseindoust S. H. Lee J. S. Kim Y. H. Choi I. K. Kwon B. J. Chae 《Journal of animal physiology and animal nutrition》2017,101(5):e98-e107
This study was conducted to investigate the effects of bacteriophages in different environments on growth performance, digestibility, ileal and caecal microbiota, gut morphology and immunity of weanling pigs. Two hundred piglets were randomly assigned to four treatment groups with five replicate pens with 10 pigs per pen. A 2 × 2 factorial arrangement of treatments was used to investigate the response of weanling pigs to supplemental bacteriophages (0 and 1.0 g/kg of diet) in contaminated or hygienic environments. Bacteriophages supplementation did not affect average daily gain (ADG), average daily feed intake (ADFI) and gain:feed in phases I and III; however, there was a significant improvement in ADG and gain:feed in phase II. The supplementation of bacteriophages increased the overall gain:feed of pigs. The overall result showed a greater ADG and ADFI in hygienic room. There were reductions in population of both ileal (p < 0.05) and caecal (p < 0.01) Clostridium spp. and ileal coliforms (p < 0.01) with the inclusion of bacteriophages in the diet. Bacteriophages increased ileal Lactobacillus and caecal Bifidobacterium and tended to increase ileal Bifidobacterium (p = 0.08). Contaminated environment decreased ileal Lactobacillus and caecal Bifidobacterium and tended to increase ileal Clostridium (p = 0.08) and coliforms (p = 0.08). Total anaerobic bacteria was tended to decrease (p = 0.06) in contaminated environment. Jejunal villus height increased in pigs received bacteriophages, but they did not affect other morphological items. The interaction between bacteriophages and environment tended to be significant (p = 0.06) for ileal villus height and ileal villus height to crypt depth ratio. The overall faecal score was significantly greater in hygienic environment and bacteriophages groups. The present findings indicate that there is an interactive effect on feed efficiency between bacteriophages and contaminated environment. In addition, bacteriophages improve jejunum morphology, and intestinal microbiota of pigs. 相似文献
22.
We evaluated a recently developed live vaccine candidate for fowl typhoid (FT)-JOL916, a lon/cpxR mutant of Salmonella Gallinarum (SG)-by comparing its safety and efficacy with that of the well-known rough mutant strain SG9R vaccine in 6-wk-old Hy-Line hens. Forty-five chickens were divided into three groups of 15 chickens each. The chickens were then intramuscularly inoculated with 2 x 10(7) colony-forming units (CFUs) of JOL916 (JOL916 group), 2 x 10(7) CFUs of SG9R (SG9R group), or phosphate-buffered saline (control group). After vaccination, no clinical symptoms were observed in any of the groups. No differences in body weight increase were detected among the three groups postvaccination. A cellular immune response was observed at 2 wk postvaccination (wpv) in the JOL916 group with the peripheral lymphocyte proliferation assay, whereas no response was detected in the SG9R group. Elevation of SG antigen-specific plasma immunoglobulin was observed 2 and 3 wpv in the JOL916 and SG9R vaccine groups, respectively. After virulent challenge on day 25 postvaccination, 0, 1, and 15 chickens in the JOL916 group, SG9R group, and control group, respectively, died by 12 days postchallenge; the death rate of the SG9R vaccine group was statistically similar to that of the JOL916 group. Postmortem examination revealed that the JOL916 vaccine offered more efficient protection than the SG9R vaccine, with significantly decreased hepatic necrotic foci scores, splenic enlargement scores, necrotic foci scores, and recovery of the challenge strain from the spleen. Vaccination with JOL916 appears to be safe and offers better protection than SG9R against FT in chickens. 相似文献
23.
Pharmacokinetics of veterinary drugs in laying hens and residues in eggs: a review of the literature
Poultry treated with pharmaceutical products can produce eggs contaminated with drug residues. Such residues could pose a risk to consumer health. The following is a review of the information available in the literature regarding drug pharmacokinetics in laying hens, and the deposition of drugs into eggs of poultry species, primarily chickens. The available data suggest that, when administered to laying hens, a wide variety of drugs leave detectable residues in eggs laid days to weeks after the cessation of treatment. 相似文献
24.
Large scale surveillance of FMD non-structural protein (NSP) antibody in pigs was conducted to monitor for FMD virus circulation in Taiwan using Ceditest and UBI NSP ELISA kits after recurrence of FMD in 2009. A total of 53,759 serum samples were collected from pigs in the auction markets in 2009. There were 43 farms with positive FMD NSP reactors to both NSP ELISA tests in the nationwide surveillance. After tracing back, clinical examination and the NSP ELISA testing using both Ceditest and UBI on 14 follow-up serum samples from all the herds with confirmed NSP reactors in 2009, there were 4 farms classified as positive on follow-up testing criteria. In this surveillance, we have demonstrated that the NSP ELISA tests of outbreak farms followed by clinical and serological investigation could be used to detect FMD circulation in the pig population in Taiwan even while the national compulsory vaccination program is ongoing. 相似文献
25.
Objective To develop a lameness model to assess the efficacy of analgesics for alleviating pain, swelling and systemic signs of inflammation in sheep. Procedures The response to subcutaneous injection of 0.1 or 0.2 mL turpentine in a forelimb pastern (n = 4 ewes per dose) was examined at 0, 3, 6, 24, 48 and 72 h. In a second experiment, responses were measured at 0, 2, 4, 6, 8, 10, 12 and 24 h in ewes receiving 0.1 mL turpentine ± meloxicam 1 mg/kg IV at 0 h (n = 6 per group). Responses measured included forceplate pressure, skin temperature, limb circumference, nociception, leucocyte count, neutrophil : lymphocyte ratio, haptoglobin and daily feed intake. Results Turpentine injection caused a decrease in weight borne on the treated limb, increased skin temperature, increased sensitivity at the injection site and leucocytosis by 2 h and increased limb circumference by 4 h. Weight borne and sensitivity of the injected limb returned to control levels after around 24 h, whereas tissue swelling, elevated skin temperature and elevated haptoglobin levels persisted for at least 72 h. Treatment with meloxicam improved weight borne by and tolerance to pressure exerted on the turpentine‐injected limb. Conclusions The local and systemic signs of inflammation and pain, temporary reduction in function of the affected limb and partial amelioration of some of these changes by the dose of meloxicam used here suggest that injection of turpentine in the lower forelimb provides a suitable model for examining the efficacy of analgesics for alleviation of pain and inflammation in sheep. 相似文献
26.
Bacillus subtilis-based direct-fed microbials augment macrophage function in broiler chickens 总被引:1,自引:0,他引:1
Lee KW Li G Lillehoj HS Lee SH Jang SI Babu US Lillehoj EP Neumann AP Siragusa GR 《Research in veterinary science》2011,91(3):e87-e91
The present study was conducted to evaluate the function of Bacillus subtilis-based direct-fed microbials (DFMs) on macrophage functions, i.e., nitric oxide (NO) production and phagocytosis in broiler chickens. DFMs used in this study were eight single strains designated as Bs2084, LSSAO1, 3AP4, Bs18, 15AP4, 22CP1, Bs27, and Bs278, and one multiple strain DFM product (Avicorr™) containing equal amount of Bs2084, LSSAO1 and 15AP4. NO concentrations were monitored in plasma and in the supernatants from the peripheral blood-derived monocytic cells (PBMC)-derived macrophages stimulated by either chicken recombinant interferon gamma (IFNγ) or lipopolysaccharide (LPS) from Escherichia coli or Salmonella typhi. In addition, phagocytosis of fluorescent beads and green fluorescent protein (GFP)-labeled Salmonella by PBMC-derived macrophage was assayed. Plasma NO levels were significantly higher in groups given 3AP4 or Bs27 diets compared with the control group at days 7 and 14. NO production by PBMC-derived macrophages stimulated with IFNγ or LPS was apparent, although the effect was strain-dependent. Phagocytosis of fluorescent beads or GFP-labeled Salmonella by macrophages was augmented in groups on DFM-supplemented diets compared with those fed the control diet. This study describes the immunomodulatory effects of Bacillus-based DFMs on innate immunity in broiler chickens. 相似文献
27.
The detection of the meq gene in chicken infected with Marek's disease virus serotype 1 总被引:4,自引:0,他引:4
Chang KS Lee SI Ohashi K Ibrahim A Onuma M 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2002,64(5):413-417
In the genome of strains of very virulent Marek's disease virus serotype 1(vvMDV1), such as Md5 and RB1B, the meq open reading frame (ORF) encoding a 339-amino-acid bZIP protein, is present, while a slightly longer meq ORF, termed as L-meq, in which a 180-bp sequence is inserted into the meq ORF is found in other strains of MDV1, such as CV1988/R6 and attenuated JM. When chickens were infected with vvMDV1 strains and the meq gene was amplified by nested polymerase chain reaction (PCR), the meq gene was detected throughout the experimental period for 7 weeks post inoculation (pi). However, the L-meq gene was also detected at 3 to 5 weeks and 3 to 4 weeks pi. in Md5-infected and RB1B-infected chickens, respectively. In the case of chickens infected with an attenuated MDV1, the JM strain, the L-meq gene was detected at 2 to 7 weeks pi., and the meq gene was also detected at 2 to 6 weeks pi. Both L-meq and meq genes were detected in chickens infected with an attenuated nononcogenic vaccine strain of MDV1 (CVI988/R6), throughout the experimental period. Though quantitative PCR was not performed, a larger amount of the PCR products corresponding to the L-meq than the meq gene was amplified from chickens infected with JM or CVI988/R6. These results suggest that a dynamic population shift between the MDV subpopulations displaying meq and L-meq genes occurs in chickens during the course of MDV infection. Since the MDV subpopulation that displays the L-meq gene only displays it during the latent phase, the L-meq and its gene product, if any, might contribute to the maintenance of the MDV latency. 相似文献
28.
Nam-Jin Lee Jung-Won Lee Jong-Hwan Sung Yeoung-Gyu Ko Seongsoo Hwang Jong-Koo Kang 《Journal of veterinary science (Suw?n-si, Korea)》2013,14(3):249-256
This study was conducted to investigate whether administration of IH901, a ginseng intestinal metabolite, ameliorates exercise-induced oxidative stress while preserving antioxidant defense capability in rat skeletal muscles and lung. Eight adult male Sprague-Dawley rats per group were randomly assigned to the resting control, exercise control, resting with IH901 (25, 50, and 100 mg/kg) consumption (R/IH901), or exercise with IH901 (25, 50, and 100 mg/kg) consumption (E/IH901) group. The trained groups ran 35 min 2 days/week for 8 weeks. To analyze the IH901-training interaction, serum biochemical analysis, lipid peroxidation, citrate synthase, protein oxidation, antioxidant and superoxide dismutase in skeletal muscles and lung tissue were measured. Compared to the exercise control group, animals that consumed IH901 had significantly increased exercise endurance times (p < 0.05) and decreased plasma creatine kinase and lactate dehydrogenase levels (p < 0.05), while those in the E/IH901 groups had increased citrate synthase and anti-oxidant enzymes and decreased lipid peroxidation and protein oxidation (p < 0.05). In conclusion, IH901 consumption in aging rats after eccentric exercise has beneficial effects on anti-inflammatory and anti-oxidant activities through down-regulation of pro-inflammatory mediators, lipid peroxidation, and protein oxidation and up-regulation of anti-oxidant enzymes. 相似文献
29.
One-day-old Taiwan native male chicks were fed with maize-soybean rearing diets without supplemental vitamin E to 23 weeks of age. From 23 to 52 weeks of age, the cockerels (n = 90) were assigned at random to 5 dietary treatments and fed with maize-soybean diets supplemented with 0, 20, 40, 80 and 160 mg/kg of vitamin E (dl-alpha-tocopherol acetate). Pullets (225) of the same age were fed with standard diets throughout. They were artificially inseminated with one dose of 0.04 ml/bird intact and 5-fold diluted pooled semen at 31 to 43 weeks of age and at 49 weeks of age, respectively. The criteria evaluated included: semen quality, fertility and maximum and effective duration of fertility, blood characteristics, body and testes weight. Supplemental vitamin E did not affect cockerels' effective duration of fertility and percentage of fertility. However, when pullets were inseminated with diluted semen, supplementing 160 mg/kg vitamin E increased the maximum duration of fertility at 49 weeks of age. Cockerels receiving 40 to 160mg/kg supplements had higher sperm viability and motility after 39 weeks of age and those fed 80 mg/kg had higher sperm concentration at 39 weeks of age. Cockerels receiving supplements of more than 40 mg/kg vitamin E had higher body weight gain. Plasma cholesterol and testosterone were not affected by supplemental vitamin E. However, plasma luteinising hormone (LH) concentration was lower in cockerels fed 160 mg/kg. Lack of supplemental vitamin E over 39 weeks was associated with lower semen quality but did not reduce the proportion of fertile eggs laid by inseminated hens, perhaps because the insemination dose compensated for low sperm quality. We found that the maximum duration of fertility might be improved by supplementing 160 mg/kg vitamin E at 49 weeks of age. 相似文献
30.
Heechun Lee Seongchan Yeon Hyojong Lee Dongwoo Chang Kidong Eom Junghee Yoon Hojung Choi Youngwon Lee 《Veterinary radiology & ultrasound》2005,46(4):317-318
A 7-year-old female Maltese presented for evaluation of severe vomiting. A diagnosis of pylorogastric intussusception was made during ultrasonographic examination. The intussusception spontaneously underwent reduction by the following morning. 相似文献