全文获取类型
收费全文 | 436篇 |
免费 | 29篇 |
专业分类
林业 | 58篇 |
农学 | 7篇 |
基础科学 | 5篇 |
87篇 | |
综合类 | 4篇 |
农作物 | 31篇 |
水产渔业 | 49篇 |
畜牧兽医 | 147篇 |
园艺 | 33篇 |
植物保护 | 44篇 |
出版年
2024年 | 1篇 |
2023年 | 6篇 |
2022年 | 10篇 |
2021年 | 12篇 |
2020年 | 10篇 |
2019年 | 11篇 |
2018年 | 34篇 |
2017年 | 27篇 |
2016年 | 25篇 |
2015年 | 14篇 |
2014年 | 17篇 |
2013年 | 37篇 |
2012年 | 17篇 |
2011年 | 32篇 |
2010年 | 16篇 |
2009年 | 20篇 |
2008年 | 27篇 |
2007年 | 21篇 |
2006年 | 14篇 |
2005年 | 32篇 |
2004年 | 17篇 |
2003年 | 26篇 |
2002年 | 18篇 |
2001年 | 7篇 |
2000年 | 4篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1995年 | 1篇 |
1991年 | 1篇 |
1986年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1962年 | 1篇 |
排序方式: 共有465条查询结果,搜索用时 156 毫秒
421.
The effects of different proportions of the 17β‐estradiol and 17α‐methyltestosterone on growth,sex reversal and skin colouration of the electric blue hap (Sciaenochromis ahli Trewavas, 1935)
下载免费PDF全文
![点击此处可从《Aquaculture Research》网站下载免费的PDF全文](/ch/ext_images/free.gif)
This study was performed to investigate the effects of 17β‐estradiol (ES) and 17α‐methyltestosterone (MT) on growth, development, survival, sex ratio and colour change in the electric blue hap (Sciaenochromis ahli Trewavas, 1935). The hormones were not supplemented to the control feed, while six other feeds were prepared by adding 20, 40 and 60 mg kg?1 17β‐ES or 20, 40 and 60 mg kg?1 17α‐MT to each, resulting in seven different feed treatments. Average live weight of the fish supplemented with these diets was 0.42 ± 0.04 g. At the end of the study, the highest weight gain was observed in fish fed 60 mg kg?1 17α‐MT group (2.62 ± 0.11 g) and the difference with the groups fed with 17β‐ES was found to be significant. All fish fed 17α‐MT were male, while the rates of feminization in fish fed 17β‐ES at 20, 40, 60 mg kg?1 were 91.11%, 88.88% and 93.33% respectively. Survival rates were respectively determined as 80%, 95.56%, 84.44%, 93.33%, 77.78%, 84.44% and 84.44% for the control, 20, 40, 60 mg kg?1 17β‐ES and 20, 40, 60 mg kg?1 17α‐MT treatments. The best colouration was achieved in the 17α‐MT groups (P < 0.05). The L* values varied between 32.98 ± 4.44 and 61.35 ± 2.19, a* values between ?7.06 ± 0.22 and ?3.42 ± 0.11, and b* values between ?7.74 ± 0.10 and 11.65 ± 0.03, while Chroma (C*) and Hue (H°ab) angle values varied between 7.54 ± 0.22 and 13.60 ± 0.01 and between 119.76 ± 0.05 and 239.73 ± 4.86. In conclusion, the 17α‐MT feeding was found to have a greater effect on the growth, feed conversion ratio, masculunization and pigmentation of the electric blue haps than the 17β‐ES treatment. 相似文献
422.
In this study, the frequency of European pear rust (Gymnosporangium fuscum) lesions on Juniperus excelsa was investigated both on seedlings in a nursery and on forest trees in six juniper stands located in south‐western Turkey. In the nursery, lesions occurred on 0.7% of 5510 1‐year‐old seedlings and 29% of 200 2‐year‐old potted seedlings. In each of the juniper forests, 50 trees were chosen within a square of approximately 400 m2 in size. In general, rust lesions were common on the trees. On average, 49.0% of the trees had lesions; on 17.3% of the trees, the lesions were located on the trunk, on 43.3% on the branches and on 11.7% on both. In lesion‐bearing trees, the average number of lesions was 1.47–3.59 and the maximum number of lesions per tree were six to 11. Most of the lesions (85.1%) were on branches. There were significant differences between the stands, which can be attributed to different age of the trees, site factors and the presence of alternate hosts. The rust identified from stem lesions in forest trees and from nursery seedlings was European pear rust (G. fuscum), but possible co‐occurrence of other Gymnosporangium spp. cannot be excluded. 相似文献
423.
Four‐year‐old seedlings of Abies nordmanniana ssp. bornmülleriana and 5‐year‐old seedlings of Abies nordmanniana ssp. nordmanniana were inoculated on the lower stem with 28 Heterobasidion abietinum isolates originating from four different regions of Turkey. Replicate seedlings were incubated in greenhouse and growth chamber. After 7 weeks, infection incidence, mortality, lesion length in the inner bark and fungal growth in the sapwood were examined. Infection incidence in different host–incubation combinations ranged between 70.5 and 79.5% and the average mortality rate was 4.2%. Average lesion lengths varied between 8.4 and 33.9 mm, and average fungal growth between 18.7 and 34.8 mm. There was a significant positive correlation between lesion length in the inner bark and fungal growth in sapwood on both hosts and conditions. Clear differences in virulence between H. abietinum isolates originating from different regions were not found. The results indicate that H. abietinum is pathogenic on both investigated subspecies of A. nordmanniana. Both lesion length and fungal growth were greater on ssp. bornmülleriana, indicating that it would be more susceptible than ssp. nordmanniana. 相似文献
424.
Gürbulak K Pancarci M Ekici H Konuk C Kirşan I Uçmak M Toydemir S 《Acta veterinaria Hungarica》2005,53(2):249-255
In this study, the efficacy of aglepristone and/or intrauterine antibiotic administration for the treatment of bitches with cystic endometrial hyperplasia/pyometra complex was investigated. Twenty-four bitches (5-12 years old) with the diagnosis of pyometra were treated at the University of Kafkas and at Istanbul University. The diagnosis of pyometra was established on the basis of the results of clinical, ultrasonographic and vaginal examinations, the haematological and biochemical findings and the history data. In Group I (n = 13), aglepristone (Antiprogestin, Alizine, Virbac, France; 0.33 ml/kg, s.c.) was administered on days 1, 2, 7, and 14 (day 1: diagnosis). In Group II (n = 11), intrauterine antibiotic treatment was performed according to the antibiogram on days 1, 2, 4, 6, 8 in addition to aglepristone given as in Group I. Clinical and ultrasonographic examinations, haematological results and occurrence of oestrous cycles revealed that the ratio of effectively treated bitches was 6/13 and 9/11 in Groups I and II, respectively. 相似文献
425.
Seroprevalence of five different Leptospira interrogans serovars, Toxoplasma gondii and Leishmania infantum in stray dogs in Ankara was investigated. A total of 116 dog sera collected from apparently healthy stray dogs were tested for L. interrogans serovars by microscopic agglutination test (MAT), for T. gondii antibodies by Sabin-Feldman dye test (SFDT), and for L. infantum antibodies by indirect fluorescence antibody test (IFAT). Of the 116 dogs, 51 (43.96%) were seropositive for leptospirosis, 72 (62.06%) for T. gondii and 3 (2.58%) for L. infantum. No statistically significant difference was observed between male and female dogs in the seroprevalences of toxoplasmosis and leptospirosis (P>0.05), but statistically significant difference was observed among different age groups in the seroprevalences of toxoplasmosis and leptospirosis (P<0.05). Although the seroprevalence of L. infantum was low, asymptomatic animals should be considered as a reservoir for the spread of the disease. 相似文献
426.
In this study, arteries that supply the septum interventriculare in donkeys, their course and variations, if present, were defined. Six hearts belonging to donkeys of varying age and sex constituted the material of the study. In order to expose the arteries, latex coloured with Rotring ink was injected into a. coronaria sinistra and a. coronaria dextra and dissection was performed. The arterial vascularization of the heart in donkeys is supplied by a. coronaria sinistra and a. coronoria dextra, which have their origin at the aorta. A. coronaria sinistra gives off two branches: one is ramus interventricularis paraconalis, which extends into the sulcus interventricularis paraconalis and the other is ramus circumflexus sinister, which lies within the sulcus coronarius. A. coronaria dextra is formed by the union of ramus interventricularis subsinuosus and ramus circumflexus dexter. Septum interventriculare is supplied by rr. septales, which originate from ramus interventricularis paraconalis, a branch of a. coronaria sinistra, as well as rami septales which have their origin in ramus interventricularis subsinuosus, a branch of a. coronaria dextra. 相似文献
427.
Biochemical and Haematological Measurements in Beef Cattle in Mendoza Plain Rangelands (Argentina) 总被引:1,自引:1,他引:0
Grünwaldt EG Guevara JC Estévez OR Vicente A Rousselle H Alcuten N Aguerregaray D Stasi CR 《Tropical animal health and production》2005,37(6):527-540
Biochemical and haematological measurements were used to identify constraints on productivity in beef cattle. One hundred
and twelve Aberdeen Angus and Criollo Argentine females including lactating cows, dry non-pregnant cows and heifers were selected.
Blood samples were taken in the middle of summer and autumn. Serum was analysed for haemoglobin, PCV, glucose, albumin, urea,
creatinine, Ca, P, Mg, Fe, Cu, ALP, AST, ALT, CK, LDH, Cl∼, Na and K content. Globulin was calculated by taking the difference
between total protein and albumin. Percentages of all cattle that had metabolite levels outside reference ranges were: 15%
(glucose), 8% (globulin), 5% (urea), 96% (Ca), 50% (P), 12% (Mg), 20% (Na), 5% (K), 24% (Cl), 18% (Fe), 5% (Cu) and 85% (CK).
These results indicate with some certainty that dietary protein was not limiting. Body condition score loss was detected only
in lactating cows. There were a few animals that could have presented chronic inflammatory disease. Phosphorus could be an
important potential constraint on fertility, although the presence of symptoms of hypophosphataemia was not observed. The
study also demonstrates the absence of anaemia or liver disease. Breed, seasonal and physiological state differences in some
blood metabolites could be attributed to one or more of the following factors: chemical composition of the feed ingested,
environmental temperature, nutrient content of the forage, animal age and cattle foraging experience. The study provides a
basis for implementing helpful adjustments in current cattle management practices so as to alleviate the constraints on productivity,
provided that these practices are profitable. 相似文献
428.
L.?ConciEmail author N.?Meneguzzi E.?Galdeano L.?Torres C.?Nome S.?Nome 《European journal of plant pathology / European Foundation for Plant Pathology》2005,113(3):255-265
A phytoplasma infecting alfalfa crops was detected and characterised in Argentina, the Argentinean Alfalfa witches′-broom
(ArAWB) phytoplasma. Typical witches′-broom symptoms were observed in diseased alfalfa plants from fields of the ‘Cuyo’ region
in the Andean midwest. Pleomorphic bodies were observed by electron microscopy in sieve tubes of the diseased plants. The
results obtained from the sequence homology, similarity coefficients derived from RFLP of the 16S rDNA and phylogenetic analysis
led us to include this phytoplasma in the 16Sr VII (Ash Yellows) group. However, the ArAWB phytoplasma showed several differences
when compared to other members of group 16Sr VII. The RFLP analysis of partial 16S rRNA gene of two ArAWB isolates, digested
with 16 restriction enzymes, showed differences between the ArAWB and the reference strain (AshY1T) in six enzyme patterns. Restriction patterns unique for the group and an exclusive HinfI restriction site were found in the ArAWB phytoplasma rDNA. Moreover, the similarity coefficients (0.92–0.86) were lower
than those obtained among other group members. The significant differences detected suggested that this phytoplasma belonged
to a subgroup different from those described so far. We propose therefore, that the ArAWB phytoplasma should be included in
a new VII-C subgroup, closely related to the EriWB phytoplasma (VII-B) described in Brazil. 相似文献
429.
The aim of this study was to define the arteries that supply the cardiac muscle in donkeys with regard to their course and possible variations. Six hearts belonging to donkeys of different age and sex constituted the material of the study. Following exposition of the arteries by means of injection of latex coloured with Rotring ink to a. coronaria sinistra and a. coronaria dextra, dissection was performed. The arterial vascularization of the heart in donkeys was determined to be supplied by a. coronaria sinistra and a. coronaria dextra which originate from the aorta. A. coronaria sinistra, measured to be larger than a. coronaria dextra, was determined to have its origin at the aorta, at the level of the free border of valvula semilunaris sinistra, and to extend between truncus pulmonalis and auricula sinistra. The mentioned artery was detected to give off two branches, namely, ramus interventricularis paraconalis and ramus circumflexus sinister which extend in sulcus interventricularis paraconalis and sulcus coronarius, respectively. However, a. coronaria dextra was determined to have its origin at the beginning of the aorta, at the level of valvula semilunaris dextra, and to extend to margo ventricularis dexter between truncus pulmonalis and auricula dexter. This study has revealed ramus interventricularis subsinuosus and ramus circumflexus dexter to intercommunicate by means of anastomosis and to form a. coronaria dexter. Examination of material revealed the absence of anastomosis between r. circumflexus sinister and r. circumflexus dexter. Branches named rami septales, originating from ramus interventricularis paraconalis and ramus interventricularis subsinuosus were determined to supply septum interventriculare. Ramus proximalis atrii sinistri was determined to have its origin at ramus circumflexus sinister whereas ramus proximalis venriculi dextri was determined to stem from the beginning of a. coronaria dextra in the material of this study. However, examination of the cranial and caudal branches of ramus coni arteriosi, revealed the cranial branch to be ramus proximalis ventriculi dextri in a cadaver. 相似文献
430.
In the present study, the distributional pattern of the penile artery and the vessels joining the blood supply of the penis were investigated in the New Zealand rabbit. Eight adult rabbits were used in the study. In order to exhibit the vascular network by dissection, latex was injected via the abdominal aorta. The main vessel which supplies blood to the penis, the penile artery, is a branch of the internal pudendal artery. It divides into two branches which form the deep and dorsal penile arteries at the level of the ischiadic arch. The deep penile artery penetrates the tunica albuginea, and forms the arterial network of corpus cavernosum penis. On the other hand, the dorsal penile artery gives off three small branches for the subischiocavernosus muscle and at the level of the attachment of this muscle sends two small branches for the preputium. The course of both arteries follows the dorsolateral surface of the penis to the glans and ends in an anastomosis. Hence, a caudal branch of the prostatic artery which originates from the umbilical artery joins the blood supply of the penis in the rabbit. After vascularizing the prostate complex, it ends by entering the corpus spongiosus penis at the dorsolateral surface at the level of the ischiadic arch. 相似文献