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   62篇
  免费   4篇
林业   2篇
农学   1篇
基础科学   2篇
  1篇
综合类   10篇
农作物   3篇
水产渔业   2篇
畜牧兽医   44篇
植物保护   1篇
  2020年   2篇
  2019年   1篇
  2018年   3篇
  2017年   1篇
  2015年   1篇
  2014年   1篇
  2013年   7篇
  2012年   2篇
  2011年   3篇
  2010年   4篇
  2009年   4篇
  2008年   1篇
  2007年   3篇
  2006年   2篇
  2005年   2篇
  2004年   3篇
  2003年   3篇
  2002年   1篇
  2000年   1篇
  1999年   2篇
  1998年   1篇
  1997年   3篇
  1996年   7篇
  1995年   1篇
  1991年   3篇
  1990年   2篇
  1989年   1篇
  1983年   1篇
排序方式: 共有66条查询结果,搜索用时 31 毫秒
51.
The Global Oscillation Network Group (GONG) project estimates the frequencies, amplitudes, and linewidths of more than 250,000 acoustic resonances of the sun from data sets lasting 36 days. The frequency resolution of a single data set is 0.321 microhertz. For frequencies averaged over the azimuthal order m, the median formal error is 0.044 microhertz, and the associated median fractional error is 1.6 x 10(-5). For a 3-year data set, the fractional error is expected to be 3 x 10(-6). The GONG m-averaged frequency measurements differ from other helioseismic data sets by 0.03 to 0.08 microhertz. The differences arise from a combination of systematic errors, random errors, and possible changes in solar structure.  相似文献   
52.
Abstract

AIMS: To obtain information and compare the prevalence of Chlamydiaceae in riverine buffalo (Bubalus bubalis) and cows (Bos taurus) in Egypt with and without clinical signs of reproductive disease.

METHODS: Vaginal swabs and blood samples were collected from animals attending Governmental Veterinary Clinics without (buffalo n=39, cows n=20) and with (buffalo n=63, cows n=53) signs of reproductive disease. Serum samples were tested for antibodies to Chlamydiaceae using complement fixation testing (CFT). Vaginal swabs were tested for Chlamydiaceae following inoculation into Vero cells and 6-day-old embryonated chicken eggs, using modified Giménez and immunoperoxidase staining, PCR analyses targeting the omp2 gene, and Restriction Fragment Length Polymorphism PCR (RFLP-PCR) for species identification.

RESULTS: Antibodies to Chlamydiaceae were detected in 30/39 (77%) and 50/63 (79%) buffalo without and with signs of reproductive disease, respectively, and 10/20 (50%) and 39/53 (74%) of cows with and without signs of reproductive disease, respectively. Positive samples from PCR analysis were identified in 31/39 (79%) and 37/63 (59%) buffalo without and with signs of reproductive disease, respectively, and 12/20 (60%) and 46/53 (89%) of cows without and with signs of reproductive disease, respectively. Using RFLP-PCR, 57/68 (84%) of samples from buffalo, and 47/58 (81%) from cows, were identified as Chlamydophila psittaci and the reminder as Cp. abortus. From the CFT and PCR results there was no significant difference in the prevalence of positive samples between species, or between animals without or with signs of reproductive disease.

CONCLUSION: The presence of anti-Chlamydiaceae antibodies in 77% of the animals with signs of reproductive disease and the detection of Chlamydiaceae in 72% of vaginal swabs of the animals suggest a pathogenic role by Chlamydiaceae in riverine buffalo and cows. The main Chlamydiaceae found in the genital tract of cattle in Egypt were Cp. psittaci and Cp. abortus.

CLINICAL RELEVANCE: Chlamydophila spp. should be included in diagnostic algorithms for reproductive disorders, in order to assess the real burden of Chlamydophila associated disease in buffalo and cattle and to evaluate the potential value of vaccines.  相似文献   
53.
AIMS: To study the adhesion properties of a biotype 4, serotype O:3 (human pathogenic) strain of Yersinia enterocolitica and to determine if adhesion in vitro and colonisation in vivo can be prevented by competition with a biotype 1A, serotype O:6,30 (non-pathogenic) strain. To study interaction between Y. enterocolitica biotype 4, serotype O:3 and cultured epithelial cells using the synthetic tripeptide arginine-glycine-aspartic acid (RGD).

METHODS: The human intestinal epithelial (HEp-2) cell line was used for in vitro studies. Inocula of Y. enterocolitica biotype 4, serotype O:3 radiolabelled using tritium were incubated with HEp-2 cells and RGD tripeptide, or with Y. enterocolitica biotype 1A, serotype O:6,30 sequentially or concurrently, then washed and lysed, and radioactivity measured to determine the effect of RGD on adhesion, and competitive exclusion of pathogenic by non-pathogenic bacteria. For in vivo studies, two groups of 5-week-old piglets (n=5/group) were sequentially inoculated orally with 5x109 colony forming units (cfu) of either a non-pathogenic biotype 1A, serotype O:6,30 strain of Y. enterocolitica followed by a pathogenic biotype 4, serotype O:3 strain, or vice versa. Pigs were monitored for carriage of strains using bacterial culture and a multiplex polymerase chain reaction (PCR).

RESULTS: The RGD tripeptide significantly inhibited adherence of the pathogenic Y. enterocolitica strain to cultured epithelial cells, suggesting that adhesion involved the RGD tripeptide sequence. The non-pathogenic biotype 1A, serotype O:6,30 strain of Y. enterocolitica prevented adhesion of the pathogenic strain to cells in vitro when allowed to adhere first. Pathogenic Y. enterocolitica was consistently isolated from rectal swabs from 80-100% of pigs on all sampling occasions but not from oral swabs after 14 days in pigs first inoculated with the non- pathogenic strain or at 26 days in pigs first inoculated with the pathogenic strain.

CONCLUSIONS: A non-pathogenic strain of Y. enterocolitica reduced adhesion of a human pathogenic strain in vitro but not in vivo.  相似文献   
54.
Studies were conducted to examine the possibility of preserving slaughterhouse‐derived buffalo ovaries at 4°C for 0 (control), 12 and 24 h to maintain the developmental competence of the oocytes (experiment 1), to assess the effect of incubation temperature during oocyte maturation on rates of in vitro maturation (IVM) and in vitro fertilization (IVF) of buffalo oocytes and embryo development (experiment 2), and to examine the effect of storage at 25°C for 0 (control), 4 and 8 h of frozen–thawed buffalo sperm and BO and H‐TALP as sperm processing and fertilization media on cleavage and embryo development in vitro of buffalo oocytes (experiment 3) in order to optimize the IVF technology in buffalo. Results suggested that storage of ovaries at 4°C for 12 or 24 h significantly (p < 0.05) reduced the developmental potential of oocytes. Incubation temperatures during the IVM influenced the fertilization rate but had no significant effect on maturation and subsequent embryo development. The incubation temperature of 38.5°C during IVM was found to be optimum for embryo production in vitro. Storage of frozen–thawed sperm at 25°C for 8 h significantly (p < 0.05) decreased its ability to cleave the oocytes. Sperm processed in BO medium had significantly (p < 0.05) higher ability to cleave the oocytes than the H‐TALP medium.  相似文献   
55.
Pharmacologically-induced luteolysis or treatment with an antiprogestin in early post-implantation pregnancy in dogs results in asynchronous death and resorption of conceptuses, indicating variable rates of response of individual conceptuses towards progesterone deficiency. This variability also seems to occur in bitches showing pregnancy failure in response to spontaneous luteal deficiency. In a total of 10 beagle pregnancies (two consecutive pregnancies of five bitches), abortifacient treatments beginning on day 24 after ovulation (ov) involved either administration of a progestin antagonist (total of six pregnancies, in three bitches) or a luteolytic regimen of prostaglandin F-analogue together with a dopamine agonist (total of four pregnancies, in two bitches). The outcomes were evaluated in relation to four control pregnancies in two bitches by assay of serum progesterone, prolactin and relaxin at selected time points or within selected time periods, by ultrasound of conceptuses including measurement of uterine blood flow, and parameters of the blood fibrinolytic system including plasma fibrinogen and plasminogen. The process of embryonic death and conceptus resorption was variable in onset and duration both in bitches that received the progesterone antagonist aglepristone (AGLE) and in those under the luteolytic treatment (cloprostenol combined with cabergoline). Pregnancy termination (death of all embryos or foetuses, respectively) occurred as early as day 29 and as late as day 41 after ov in AGLE-treated bitches, and not earlier than day 37 after ov in luteolytic-treatment bitches. Impending embryonic death was not predicted by changes in relaxin concentration, parameters of the fibrinolytic system, or in the perfusion of small uteroplacental vessels.  相似文献   
56.
Objective   To evaluate the treatment efficacy of a topical spray containing hydrocortisone aceponate (HCA) on dogs with flea-allergy dermatitis (FAD).
Design   A controlled clinical study was conducted on dogs with experimentally induced FAD. Sixteen laboratory beagles with mild to moderate clinical signs were divided into two groups. The test group received HCA by topical spray once daily for 7 days, while the control group did not. Pruritic events (time and frequency) were videotaped and then scored. Clinical signs (erythema, papules, excoriation and alopecia) present on four anatomical regions were monitored and their severity directly assessed.
Results   After 2 days, pruritus was reduced by 94% in the treatment group and by 24% in the control group (P = 0.014) in cumulative time, and by 86% versus 34% (P = 0.034) in frequency. The HCA spray also resulted in significant improvements in overall clinical signs: 23% versus 0% in the control group (P = 0.0006) on day 3 and 43% versus 15% in the control group (P = 0.0006) on day 7. During the 7-day trial, no drug-related adverse effects were observed.
Conclusions   Topical treatment with HCA showed a rapid and potent antipruritic effect on dogs with FAD. HCA also demonstrated significant overall therapeutic effects on FAD-associated skin lesions.  相似文献   
57.
Oestrogens are essential for male fertility targeting the testicular-epididymal compartment. However, the underlying mechanisms are only vaguely known and species specificities must be considered. The boar has a remarkably high testicular-oestrogen output, with the biologically inactive oestrone-sulphate being the major oestrogen occurring in the testicular vein. In the boar testis and epididymis, activity of steroid sulphatase (StS) and oestrogen sulphotransferase has been demonstrated. Thus apart from their synthesis in Leydig cells, provision of biologically active free oestrone seems also to depend on the activity and localization of these enzymes. Our aim was to establish expression patterns and activity of StS in boar testis. Testes were randomly collected from healthy boars and allotted to five age groups, five animals in each, aged 50, 100, 150, 200 and 250 days. Three extra boars aged over 250 days were castrated to obtain fresh tissue for enzyme activity tests. Immunohistochemistry detected StS only in the cytoplasm of Leydig cells and – except for day-50 group in which 65.1 ± 4.9% (X ± SD) of the cells were positive – expression was constant with virtually all the cells staining positive. RT-PCR and in situ hybridization confirmed expression and localization of StS mRNA. The V max and K m value (X ± SD) for StS was 24.05 ± 0.3 fmol/s/μg protein and 2.15 ± 0.12 μ m . These data suggest that StS within the Leydig cells of the boar is involved in modulation of testicular oestrogen bioavailability and that the site of sulpho-conjugation is not the testis but a different compartment of the testes–epididymidis complex.  相似文献   
58.
Two anasarcous foetuses of Awassi sheep are described. The foetuses were removed from the dams by caesarean section because of dystocia due to failure of cervical dilation. Uterine incision was made in situ because uteri were so distended they could not be brought out from the site of incision. Large quantities of uterine fluids and abnormal thick placentas were found. One foetus weighed about 7 kg and the other 13 kg. The foetal heads were deformed: the upper jaw was prognathic and the left ear of the small foetus was cystic. Necropsy revealed subcutaneous musculature was soft and flabby and abdominal and thoracic cavities contained serosanguinous fluid. Histopathological examination revealed that only the larger foetus had focal aggregates of basophilic nucleated red blood cells and scattered megakaryocytes in the liver. We conclude that anasarca can occur in Awassi sheep, with and without associated extramedullary haematopoiesis.  相似文献   
59.
[目的]分析利比亚WadiBay干谷地区地下水水化学特征的形成原因,为地下水资源合理开发利用以及地下水环境保护提供科学依据。[方法]以利比亚Wadi 8Bay(Bay干谷)地区为例,运用Piper三线图示法、描述性统计、离子比例系数法、同位素证据,系统研究了利比亚WadiBay地区干旱气候条件下浅层地下水特殊的水化学特征。[结果]区域地下水含盐量很高,矿化度(TDS)在3.2~8.4g/L,地下水类型主要为Cl、SO4--Na、Ca,其次为Cl.SO4-Na、Ca、Mg;地下水中Cl-、Na+、SO42-等在距海70km处浓度产生突变,而Mn2+、Ba2+、Si2+、NH4+与NO3-并无同样突变现象。[结论]比亚WadiBay干谷地区浅层地下水水化学特征与溶虑作用、蒸发浓缩作用以及人类活动关系不大,主要成因为海水入侵过程中的咸淡水混合作用。  相似文献   
60.

Background

Every year many dogs in Sweden are bitten by Vipera berus, the only venomous viper in Sweden. This prospective study investigated clinical signs, some biochemical parameters, treatment, and progress of disease after snakebite in 53 dogs. Effects of treatment with and without glucocorticoids were evaluated.

Methods

All fifty-three dogs bitten by Vipera berus were examined the same day the dog was bitten and the next day. Two more examinations during 23 days post snake bite were included. Creatinine, creatine kinase (CK), alanine aminotransferase (ALT), glutamate dehydrogenase (GLDH), alkaline phosphatase (ALP) and bile acid results were followed through 3 to 4 samplings from 34 of the dogs.

Results

All dogs had variable severity of local swelling in the bite area and 73 per cent had affected mental status. Initial cardiac auscultation examination was normal in all dogs, but six dogs had cardiac abnormalities at their second examination, including cardiac arrhythmias and cardiac murmurs. All dogs received fluid therapy, 36 dogs were given analgesics, 22 dogs were treated with glucocorticoids, and ten dogs were treated with antibiotics. Evidence of transient muscle damage (increased CK) was seen one day after the snake bite in 15 (54%) of 28 sampled dogs. Moderate changes in hepatic test results occurred in 1 dog and several dogs (22 of 34) had transient, minor increases in one or more hepatic test result. No dog died during the observation period as a consequence of the snake bite.

Conclusions

Snake bite caused local swelling in all dogs and mental depression of short duration in most dogs. Some dogs had transient clinical signs that could be indicative of cardiac injury and some other had transient biochemical signs of liver injury. Treatment with glucocorticoids did not have any clear positive or negative effect on clinical signs and mortality.  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