全文获取类型
收费全文 | 2487篇 |
免费 | 133篇 |
专业分类
林业 | 210篇 |
农学 | 290篇 |
基础科学 | 31篇 |
564篇 | |
综合类 | 115篇 |
农作物 | 195篇 |
水产渔业 | 301篇 |
畜牧兽医 | 640篇 |
园艺 | 69篇 |
植物保护 | 205篇 |
出版年
2023年 | 36篇 |
2022年 | 73篇 |
2021年 | 82篇 |
2020年 | 100篇 |
2019年 | 122篇 |
2018年 | 152篇 |
2017年 | 149篇 |
2016年 | 119篇 |
2015年 | 83篇 |
2014年 | 116篇 |
2013年 | 222篇 |
2012年 | 177篇 |
2011年 | 153篇 |
2010年 | 131篇 |
2009年 | 92篇 |
2008年 | 103篇 |
2007年 | 96篇 |
2006年 | 82篇 |
2005年 | 58篇 |
2004年 | 50篇 |
2003年 | 42篇 |
2002年 | 30篇 |
2001年 | 40篇 |
2000年 | 34篇 |
1999年 | 25篇 |
1998年 | 18篇 |
1997年 | 15篇 |
1996年 | 9篇 |
1995年 | 6篇 |
1994年 | 7篇 |
1993年 | 6篇 |
1992年 | 11篇 |
1991年 | 14篇 |
1990年 | 13篇 |
1989年 | 10篇 |
1988年 | 11篇 |
1987年 | 12篇 |
1986年 | 7篇 |
1985年 | 6篇 |
1984年 | 7篇 |
1983年 | 8篇 |
1982年 | 5篇 |
1981年 | 9篇 |
1980年 | 5篇 |
1979年 | 14篇 |
1974年 | 8篇 |
1973年 | 8篇 |
1971年 | 7篇 |
1969年 | 6篇 |
1967年 | 4篇 |
排序方式: 共有2620条查询结果,搜索用时 15 毫秒
71.
Bhupamani Das Niranjan Kumar Mehul M. Jadav Jayesh B. Solanki T.K.S. Rao 《Tropical animal health and production》2017,49(8):1577-1589
This study aims to evaluate the conjunctiva colour-based FAMACHA score (FS) coupled with a body condition score (BCS), haemogram and stressor hormone level estimation, in identifying post-mortem (PM)/coproscopically proven individuals wanting therapy for economically important gastrointestinal (GI) helminths, Haemonchus contortus, in the small ruminants. The incidence of haemonchosis was significantly (p < 0.05) higher (60.81%) in the ruminants with FS = 3. The H. contortus count in the animals with FS 2, 3 and 4 was 23.2 ± 0.37, 62 ± 2.5 and 74 ± 3.2 (p < 0.05) [positive correlation (r = 0.841 in goats; r = 0.828 in sheep, p < 0.05)], respectively, with corresponding 2.8 ± 0.15, 2 ± 0.3 and 2 ± 0.16 BCS (negative correlation, p > 0.05). The infected animals of FS 2, 3 and 4 measured 8.2 ± 0.0, 7.5 ± 0.23 and 6.7 ± 0.34 g/dl Hb (r = ?0.452, p = 0.01) in goats/9.3 ± 0.8, 8.6 ± 0.5 and 7.6 ± 0.3 g/dl Hb (r = ?0.511, p = 0.05) in sheep with 21.2, 19.8 ± 1.8 and 17.8 ± 0.2% PCV (r = ?0.369, p = 0.05) in goats/26.7 ± 1.2, 22.2 ± 0.2 and 20.9 ± 0.6% PCV (r = ?0.251, p = 0.03) in sheep, respectively. The FS 2, 3 and 4 infected goats/sheep measured 6.1 ± 0, 7.9 ± 1.0 and 9.5 ± 0.9 (p < 0.05)/5.8 ± 2.3, 6.9 ± 1.2 and 7.8 ± 0.2% (p < 0.05) mid-granulocyte [(r = 0.928 (goats)/0.834 (sheep), p < 0.05], while the cortisol level was 15.6, 23 ± 4.5 and 42 ± 2.3 (p = 0.23)/12.1 ± 0, 15.9 ± 1.2 and 24 ± 3.4 (p = 0.29) μg/dl, respectively. The infected ruminants recorded low (p < 0.05) level of Hb/PCV while high level of mid-granulocytes/cortisol. Specificity of FAMACHA test was maximized (100%) when FS = 4 was considered anaemic, but sensitivity was low (35.29% in goats; 25% in sheep). The false negatives was 5.9 (goat)/12.5 (sheep)% when FS ≥ 3 was considered anaemic. The small ruminants with FS ≥ 3, BCS ≤ 2.5, Hb ≤ 7.5 g/dl (goats)/8.6 g/dl (sheep), PCV ≤ 19.8% (goats)/22.2% (sheep) and mid-granulocyte ≥7.9% (goats)/6.9 ± 1.2% (sheep) can be subjected to target-selective treatment for haemonchosis in the field simultaneously maximizing the economic benefit to the farmers. 相似文献
72.
Panja Suraj Mondal Kongkong Kar Rup Kumar Dey Pradip Chandra Dey Narottam 《Journal of Crop Science and Biotechnology》2023,26(1):87-95
Journal of Crop Science and Biotechnology - Assamese Bora rice lines are valuable genetic resource for their socio-economic importance and traditional usage. Being lowland rice lines of upper... 相似文献
73.
Suphla Bajpai Seema Prajapati Rajesh Luthra Srikant Sharma A Naqvi Sushil Kumar 《Genetic Resources and Crop Evolution》1999,46(5):435-439
The variation in the seed shape, colour and yield, and content, yield and fatty acid composition of seed oil of 109 accessions of opium poppy Papaver somniferum, (majority of them Indian land races), was investigated. The seeds were white, pale yellow or light brown in colour, reniform or round in shape and varied in size up to three fold. The oil content, seed and the oil yield varied between 26 to 52%, 1.0 to 7.4 g/plant and 0.4 to 2.7 g/plant, respectively. The % content of palmitic, oleic and linoleic acid in the seed oil ranged between 9.3 to 40.0%, 7.5 to 58.4% and 0.7 to 72.7%, respectively. On average basis, the levels of major fatty acids in the seed oil were: oleic (37.1%) > palmitic (27.3%) > linoleic acid (17.2%). The palmitoleic, stearic and linolenic acids were present in the oils of only some of the accessions. Two of the accessions yielded linoleic acid rich seed oil of about the same quality as soybean and maize oils, and in four accessions, the proportion of palmitic, oleic and linoleic acids was roughly equal. The palmitic acid was relatively less and linoleic acid more in the seed oil from accessions rich in oil content. The oil that contained higher amount of oleic acid also contained higher amount of palmitic acid and relatively lower amount of linoleic acid. The correlation analyses revealed a strong positive relationship between seed yield and oil yield (r = +0.81), oil yield and oil content (r = +0.54) and oleic acid and palmitic acid content in the seed oil (r = +0.49), and a weak positive relationship between oil content and linoleic acid content of oil (r = +0.24), and a negative correlation was observed between oil content and palmitic acid content (r = –0.32), palmitic acid and linoleic acid (r = –0.55) and oleic acid and linoleic acid contents of oil (r = –0.68). The observations have permitted selection of accessions that are high seed and oil yielding and/or rich in linoleic, palmitic and oleic acids or containing palmitic, oleic and linoleic acids in about equal amounts. 相似文献
74.
Satish Kumar I Vijaya Kumar C Gangaraju G Sapna Nath Thiruvenkadan A.K. 《Tropical animal health and production》2017,49(7):1431-1438
In the present study, (co)variance components and genetic parameters in Nellore sheep were obtained by restricted maximum likelihood (REML) method using six different animal models with various combinations of direct and maternal genetic effects for birth weight (BW), weaning weight (WW), 6-month weight (6MW), 9-month weight (9MW) and 12-month weight (YW). Evaluated records of 2075 lambs descended from 69 sires and 478 dams over a period of 8 years (2007–2014) were collected from the Livestock Research Station, Palamaner, India. Lambing year, sex of lamb, season of lambing and parity of dam were the fixed effects in the model, and ewe weight was used as a covariate. Best model for each trait was determined by log-likelihood ratio test. Direct heritability for BW, WW, 6MW, 9MW and YW were 0.08, 0.03, 0.12, 0.16 and 0.10, respectively, and their corresponding maternal heritabilities were 0.07, 0.10, 0.09, 0.08 and 0.11. The proportions of maternal permanent environment variance to phenotypic variance (Pe2) were 0.07, 0.10, 0.07, 0.06 and 0.10 for BW, WW, 6MW, 9MW and YW, respectively. The estimates of direct genetic correlations among the growth traits were positive and ranged from 0.44(BW-WW) to 0.96(YW-9MW), and the estimates of phenotypic and environmental correlations were found to be lower than those of genetic correlations. Exclusion of maternal effects in the model resulted in biased estimates of genetic parameters in Nellore sheep. Hence, to implement optimum breeding strategies for improvement of traits in Nellore sheep, maternal effects should be considered. 相似文献
75.
Santosh Kumar Subodh Kumar Vijay Kumar Kaushal K. Singh Birendra K. Roy 《Veterinary research communications》2009,33(8):887-893
The present experiment was designed to study the pharmacokinetics of levofloxacin in six healthy cross bred female cow calves (4 to 6 months age) weighing between 40 to 80 kg. Plasma from blood was separated by centrifugation at 10,000 rpm. Quantitative estimation of levofloxacin was done by UV-VIS spectrophotometer at 286 nm. The mean maximum plasma concentration (Cpmax ) of levofloxacin in febrile calves (5.28?±?0.32 µg/ml) did not differ significantly as compared with healthy calves (4.50?±?0.22 µg/ml) after single dose (20 mg/kg) oral administration. The mean therapeutic plasma concentration ( Cpther ) of levofloxacin was maintained for longer period in febrile calves (10 h) as compared to healthy calves ( 8 h). The mean maximum urine concentration (Cumax) in febrile (40.86?±?2.19 µg/ml) also did not differ significantly as compared with healthy calves (39.38?±?2.43 µg/ml). No significant difference in various pharmacokinetic parameters of plasma was observed in healthy calves ( β?=?0.23?±?0.01/h ; t1/2 β?=?3.00?±?0.17 h and MRT?=?4.66?±?0.14 h ) and febrile calves ( β?=?0.23?±?0.01/ h; t1/2 β?=?3.05?±?0.16 h and MRT?=?5.04?±?0.14 h ) . The mean value of β, and t ½ β calculated in urine also did not differ between healthy and febrile calves. However, the value of MRT(3.79?±?0.07 h) and ClB(1.65?±?0.09 ml/kg/min) calculated in urine of febrile calves significantly(p?0.05) differ to healthy calves(MRT?=?3.15?±?0.03 h;ClB?=?2.09?±?0.13 ml/kg/min). Based on kinetic profile levofloxacin may be given orally at the dose rate of 1.49 mg/kg B.W.at 8 h intervals in febrile calves. 相似文献
76.
Identification of internal control genes in milk‐derived mammary epithelial cells during lactation cycle of Indian zebu cow 下载免费PDF全文
77.
78.
Pantu Kumar Roy Ahmad Yar Qamar Xun Fang Ghangyong Kim Seonggyu Bang Mahanama De Zoysa Sang Tae Shin Jongki Cho 《Reproduction in domestic animals》2021,56(2):342-350
Oxidative stress is inevitable as it is derived from the handling, culturing, inherent metabolic activities and medium supplementation of embryos. This study was performed to investigate the protective effect of chitosan nanoparticles (CNPs) on oxidative damage in porcine oocytes. For this purpose, cumulus–oocyte complexes (COCs) derived from porcine slaughterhouse ovaries were exposed to different concentrations of CNPs (0, 10, 25 and 50 µg/ml) during in vitro maturation (IVM). Oocytes treated with 25 µg/ml CNPs showed significantly higher levels of GSH, along with a significant reduction in ROS levels compared to control, CNPs10 and CNPs50 groups. In parthenogenetic embryo production, the maturation rate was significantly higher in the CNPs25 group than that in the control and all other treated groups. In addition, when compared to the CNPs50 and control groups, CNPs25-treated oocytes showed significantly higher cleavage and blastocyst development rates. The highest concentration of CNPs reduced the total cell number and ratio of ICM: TE cells in parthenogenetic embryos, suggesting that there is a threshold where benefits are lost if exceeded. In cloned embryos, the CNPs25 group, as compared to all other treated groups, showed significantly higher maturation and cleavage rates. Furthermore, the blastocyst development rate in the CNPs25-treated group was significantly higher than that in the CNPs50-treated group, as was the total cell number. Moreover, we found that cloned embryos derived from the CNPs25-treated group showed significantly higher expression levels of Pou5f1, Dppa2, and Ndp52il genes, compared with those of the control and other treated groups. Our results demonstrated that 25 µg/ml CNPs treatment during IVM improves the developmental competence of porcine oocytes by reducing oxidative stress. 相似文献
79.
Akhilesh Kumar Vimal Chandra Pandey Anant Gopal Singh Divya Darshan Tewari 《Genetic Resources and Crop Evolution》2013,60(1):203-224
The aim of present study was to explore and document medicinal plants used for the traditional dermatological healthcare management practices by the the Tharu tribal community of Uttar Pradesh. The study was conducted during 2000–2004. Information was gathered from 230 informants residing in 46 villages in Terai region of Indo-Nepal boarder using questionnaires; oral interviews and group discussions. Total 92 medicinal plant species were cited for the preparation of 113 crude drug formulations. Voucher specimens of cited plant species were collected and identified as belonging to 82 genera and 49 families. Thirty-nine medicinal plant species were reported for the first time for dermatological healthcare problems from India. The dermatological healthcare problems managed were cut and wounds, ringworm, leprosy, eczema, scabies, leucoderma, boils, carbuncles, pimples, skin blemishes, spots, eruption, and burns etc. The most commonly and popularly used medicinal plant species for management of dermatological healthcare problems in the study area were Curcuma longa L., Azadirachta indica A. Juss and Melia azedarach L. It is concluded that dermatological healthcare management practice in the study area depends largely on wildly growing medicinal plant species. There is an urgent need to properly conserve the medicinal plant species growing in this area for human welfare. There is also need for further phytopharmacological studies to provide scientific explanation for the usages of 57 medicinal plant species for which to the best of our knowledge phytopharmacological literatures are not available. 相似文献
80.
Phosphorylation of tyrosine residues on sperm protein is a known indicator of capacitation and a major intracellular signalling event. There is evidence that sperm cryopreservation promotes tyrosine phosphorylation and is associated with reduced fertility of spermatozoa. Under this study, cryoprotective role of different additives namely taurine, trehalose, catalase and 4‐bromophenacyl bromide on buffalo sperm quality was evaluated. Buffalo semen was cryopreserved in tris‐based egg yolk extender supplemented with additives like taurine (50 mm ) or trehalose (100 mm ) or 4‐bromophenacyl bromide (200 μm ) or catalase (100 U/ml) and used for assessment of levels of tyrosine phosphorylation in frozen‐thawed spermatozoa. The results obtained were compared with the level of protein tyrosine phosphorylation of semen cryopreserved in tris‐based egg yolk extender without additives. Proteins were extracted from a total number of nine ejaculates from three individual buffalo bulls chosen at random and analysed for tyrosine phospho‐proteins using SDS–PAGE followed by immunoblotting. Monoclonal anti‐phosphotyrosine antibody (Clone pT‐154) was used as primary antibody followed by treatment with HRP‐conjugated secondary antibody. Signals were detected on X‐ray film using chemiluminescence. Nine proteins (p20, p30, p32, p38, p49, p56, p59, p72 and p86) were found to be tyrosine phosphorylated in cryopreserved spermatozoa. Supplementation of additives significantly (p<0.05) reduced the level of protein tyrosine phosphorylation in spermatozoa. Moreover, this study showed improved (p<0.05) post‐thaw motility, viability and membrane integrity of spermatozoa on addition of these additives. The results obtained clearly indicate reduced level of capacitation like changes on supplementation of additives in terms of protein tyrosine phosphorylation. 相似文献