全文获取类型
收费全文 | 2082篇 |
免费 | 98篇 |
国内免费 | 6篇 |
专业分类
林业 | 173篇 |
农学 | 63篇 |
基础科学 | 17篇 |
409篇 | |
综合类 | 115篇 |
农作物 | 175篇 |
水产渔业 | 172篇 |
畜牧兽医 | 745篇 |
园艺 | 74篇 |
植物保护 | 243篇 |
出版年
2023年 | 17篇 |
2022年 | 58篇 |
2021年 | 71篇 |
2020年 | 76篇 |
2019年 | 93篇 |
2018年 | 79篇 |
2017年 | 111篇 |
2016年 | 98篇 |
2015年 | 62篇 |
2014年 | 80篇 |
2013年 | 136篇 |
2012年 | 139篇 |
2011年 | 133篇 |
2010年 | 92篇 |
2009年 | 84篇 |
2008年 | 104篇 |
2007年 | 85篇 |
2006年 | 92篇 |
2005年 | 84篇 |
2004年 | 69篇 |
2003年 | 51篇 |
2002年 | 67篇 |
2001年 | 21篇 |
2000年 | 15篇 |
1999年 | 18篇 |
1998年 | 6篇 |
1997年 | 14篇 |
1995年 | 9篇 |
1994年 | 8篇 |
1993年 | 10篇 |
1992年 | 6篇 |
1991年 | 8篇 |
1990年 | 13篇 |
1989年 | 7篇 |
1988年 | 10篇 |
1987年 | 11篇 |
1986年 | 7篇 |
1985年 | 15篇 |
1984年 | 9篇 |
1983年 | 6篇 |
1982年 | 5篇 |
1979年 | 6篇 |
1977年 | 8篇 |
1975年 | 4篇 |
1974年 | 4篇 |
1973年 | 9篇 |
1972年 | 4篇 |
1971年 | 4篇 |
1969年 | 4篇 |
1967年 | 4篇 |
排序方式: 共有2186条查询结果,搜索用时 15 毫秒
21.
Youssef A. Attia Fulvia Bovera Abd El-Hamid E. Abd‐Elhamid Serena Calabr Mohamed A. Mandour Mohammed A. Al‐Harthi Sabar S. Hassan 《Journal of animal physiology and animal nutrition》2019,103(3):947-958
Sixty‐four nulliparous female rabbits were distributed among eight groups (eight animals/group). Group one was the unsupplemented control group; the other seven groups were supplemented with zinc bacitracin (ZnB) at 100 mg, or bee pollen (BP) and/or propolis (Pro) at 150 and 300 mg in a capsulated form, three times a week, day after day, continuously all over the experimental period. The experiment was run for eight parties; at each parity, 28 kids of each doe group (a total of 224 rabbits) were divided into two subgroups weaned, respectively, at 24 and 30 days of age. Thus, for each parity, there were 16 groups (eight does treatments × two weaning age, 14 rabbits per group). The growing rabbits fed the standard diets without supplements. The growth performance, the carcass traits, the liver and the spleen histology of rabbits were checked up to 90 days of age to find possible carryover effects of the supplements. The supplements had no significant effect on most of the growth performance at 90 days of age, but BP150 and BP+Pro300 increased the growth rate in comparison with ZnB group. The liver weight in the control, BP300 and Pro300 groups was higher than the ZnB one. The spleen weight was higher in the groups ZnB, BP150, Pro300 and BP+Pro300, followed by the control, BP300 and BP+Pro150 and thus Pro150. The heart % in the BP150 and Pro300 groups was higher than ZnB and BP+Pro150 groups. A lymphoid hyperplasia of splenic white pulp was observed in the BP+Pro groups, while propolis alone showed a mild activation of lymphobiosis. The Pro and BP groups showed the same picture of the control group exhibiting a hydropic degeneration of mostly hepatic cells, while the ZnB group exhibited adverse effect on the bile ducts featuring portal periductal inflammatory cells infiltration with epithelial hyperplasia reflecting chronic cholangitis. 相似文献
22.
In Tunisia both Psammomys obesus and P. vexillaris are found. These taxa have been the subject of taxonomic controversy for some time, due to variability in the classical morphological characters used for taxonomic recognition. In this study we investigated skull size and shape variation in the genus Psammomys by using geometric morphometrics to evaluate the extent of intra- and interspecific shape variation and explicitly tested for the impact of allometric shape variation on species discrimination. Eleven populations of the two species from 10 localities in Tunisia were studied. Statistical analyses of size and shape showed large size variation within P. obesus, but no shape differences were revealed among populations of this species. Interspecific analysis revealed that P. vexillaris had the smallest skull. Principal component analysis and Procrustes distances showed good discrimination between the two species after removal of the allometric component of shape variation. The results obtained show that allometric-related shape variation could mask discrimination between the two Psammomys species. This finding might explain the uncertainty in classification of these species in the past. The interspecific allometric-free phenotypic differences observed may be associated with adaptive processes linked to the different environmental and trophic preferences of the two species. 相似文献
23.
24.
Effect of coated plant extracts on Histomonas meleagridis and growth of bacteria in vitro 总被引:1,自引:0,他引:1
Three coated plant extracts (RepaXol and two experimental formulations) were tested for their minimal lethal concentration for histomonads in vitro and the effect of those substances on the bacterial growth in the histomonadal culture. After 48 hr, RepaXol and experimental formulation B were lethal to histomonads at a concentration of 1.25 microl/ml. Experimental formulation C was lethal at a concentration of 2.5 microl/ml. All products also decreased the growth of bacteria at concentrations inhibiting the growth of histomonads. 相似文献
25.
Akram Ahmed Salama Mahmoud AbouLaila Ahmed A. Moussa Mohamed A. Nayel Ahmed El-Sify Mohamad A. Terkawi Hany Y. Hassan Naoaki Yokoyama Ikuo Igarashi 《Veterinary parasitology》2013,191(1-2):1-10
Fusidic acid known to has antibacterial, antifungal, and antimalarial activities. Fusidic acid blocks translation elongation factor G gene in Plasmodium falciparum. In the present study, the inhibitory effects of fusidic acid on the in vitro growth of bovine and equine Babesia parasites were evaluated. The inhibitory effect of fusidic acid on the in vivo growth of Babesia microti was also assessed. The in vitro growth of four Babesia species that were tested was significantly inhibited (P < 0.05) by micromolar concentrations of fusidic acid (IC50 values = 144.8, 17.3, 33.3, and 56.25 μM for Babesia bovis, Babesia bigemina, Babesia caballi, and Theileria equi, respectively). Combinations of fusidic acid with diminazene aceturate synergistically potentiated its inhibitory effects in vitro on B. bovis and B. caballi. In B. microti-infected mice, fusidic acid caused significant (P < 0.05) inhibition of the growth of B. microti at the dose of 500 mg/kg BW relative to control group. These results indicate that fusidic acid might be incorporated in treatment of babesiosis. 相似文献
26.
27.
Lamellodiscus dentexi Aljoshkina, 1984, a gill parasite of Dentex macrophthalmus (Bloch), is redescribed based on new material from the northwest coast of Africa (Senegal and Morocco). Three new species of Lamellodiscus Johnston et Tiegs, 1922 from D. macrophthalmus are described, Lamellodiscus toguebayei sp. n., L. vicinus sp. n., and L. triacies sp. n., all belonging to the "ignoratus" group. They can be distinguished from all other species of this group by the size and shape of male copulatory organ and sclerotised parts of the haptor. Considering the peculiar morphology of the male copulatory organ (long and thin tube) we propose to put together L. dentexi, L. virgula Euzet et Oliver, 1967 and L. obeliae Oliver, 1973 to form the "elongatus" type within the "elegans" group. 相似文献
28.
Leach TN Childress MO Greene SN Mohamed AS Moore GE Schrempp DR Lahrman SR Knapp DW 《Veterinary and comparative oncology》2012,10(2):102-112
The purpose of this study was to assess the toxicoses and antitumor activity of metronomic chlorambucil at a dosage of 4 mg m(-2) daily in dogs with naturally occurring cancer. Thirty-six dogs were enrolled in the study. The protocol was well tolerated with no grade 3 or 4 toxicoses noted. Complete remission was achieved, and lasted over 35 weeks in three dogs (mast cell tumour, soft tissue sarcoma and thyroid carcinoma). Partial remission was noted in 1 dog with histiocytic sarcoma (39 weeks duration) for an overall remission rate of 11% (4 of 36). Stable disease was noted in 17 dogs (47%) with various other cancers. The median progression-free interval was 61 days, and the median survival time was 153 days. Chlorambucil given in a metronomic protocol showed antitumor activity in dogs with a variety of naturally occurring cancers. 相似文献
29.
Gáspárdy A Ismach G Bajcsy AC Veress G Márkus S Komlósi I 《Acta veterinaria Hungarica》2012,60(1):145-155
Mastitis is a persistent, inflammatory reaction of the udder tissue, which entails a decline in potassium, and is also responsible for a higher somatic cell count (SCC) and electrical conductivity (EC) of milk. The measurement of EC is an indirect, rapid method to detect subclinical mastitis from milk. The aim of this study was to analyse the EC of milk throughout the lactation, around the day of mastitis detection, and also to estimate its heritability based on data from a large-scale dairy farm. Shortly after calving the EC value generally decreases; however, it was discovered that from the thirteenth week onwards, substantial differences arise between the mastitic and healthy groups of cows. The authors observed a significant (P < 0.001) increase in EC before the detection of clinical mastitis. This higher value (around 11 mS) persisted for 4 days, then it gradually returned to the normal level. The EC of milk from daughters sired by different bulls responded differently in case of mastitis. The heritability of EC seems to be high (h2 = 0.56). Therefore, the EC trait can be a beneficial indicator in detecting mastitis and should be considered in sire selection. 相似文献
30.
Towards sustainable farming systems: Effectiveness and deficiency of the French procedure of sustainable agriculture 总被引:2,自引:0,他引:2
Mohamed Gafsi Bruno Legagneux Genevive Nguyen Patrice Robin 《Agricultural Systems》2006,90(1-3):226-242
There is a widespread consensus about the importance of sustainable agriculture. In France, the Farming Orientation Law of July 1999 has set down a precise procedure for the implementation of sustainable agriculture: the contrat territorial d’exploitation – or territorial farm contract (TFC). This paper aims to analyse the TFC effectiveness. An analysis has been made of the TFCs signed in the Midi-Pyrenees Region in south-western France, using statistical analysis and qualitative surveys of a sample of farms. The results show that the most valuable effects have been mainly economic. Effects regarding social and environmental aspects were very limited. But from the point of view of an integrated approach, indirect effects of TFCs can be observed on social and environmental aspects. These results are explained, on the one hand, by farmers’ motivations guided by economic objectives, and on the other hand, by the dominance of professional farming organisations in the implementation of TFC’s procedure. Given these results, two ways of improving the elaboration procedure for TFCs are proposed. Firstly, technical improvements can be made to the diagnostic assessment of farms, and to the choice of actions addressed by the contract. Secondly, organisational improvements can be applied to TFCs elaboration and implementation process, in order to adopt a participatory approach which would involve all rural stakeholders. 相似文献