全文获取类型
收费全文 | 1112篇 |
免费 | 37篇 |
国内免费 | 3篇 |
专业分类
林业 | 60篇 |
农学 | 48篇 |
基础科学 | 8篇 |
212篇 | |
综合类 | 52篇 |
农作物 | 94篇 |
水产渔业 | 41篇 |
畜牧兽医 | 531篇 |
园艺 | 28篇 |
植物保护 | 78篇 |
出版年
2023年 | 14篇 |
2022年 | 11篇 |
2021年 | 27篇 |
2020年 | 32篇 |
2019年 | 34篇 |
2018年 | 45篇 |
2017年 | 55篇 |
2016年 | 34篇 |
2015年 | 16篇 |
2014年 | 36篇 |
2013年 | 80篇 |
2012年 | 63篇 |
2011年 | 63篇 |
2010年 | 51篇 |
2009年 | 44篇 |
2008年 | 40篇 |
2007年 | 48篇 |
2006年 | 37篇 |
2005年 | 33篇 |
2004年 | 39篇 |
2003年 | 22篇 |
2002年 | 23篇 |
2001年 | 27篇 |
2000年 | 31篇 |
1999年 | 31篇 |
1998年 | 13篇 |
1997年 | 9篇 |
1996年 | 7篇 |
1994年 | 6篇 |
1993年 | 5篇 |
1992年 | 14篇 |
1991年 | 19篇 |
1990年 | 20篇 |
1989年 | 17篇 |
1988年 | 12篇 |
1987年 | 11篇 |
1986年 | 10篇 |
1985年 | 4篇 |
1984年 | 6篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 6篇 |
1979年 | 7篇 |
1975年 | 5篇 |
1971年 | 3篇 |
1970年 | 6篇 |
1969年 | 7篇 |
1968年 | 5篇 |
1966年 | 2篇 |
排序方式: 共有1152条查询结果,搜索用时 15 毫秒
171.
Kaleem Ullah Kakar Y.-P. Duan Zarqa Nawaz Guochang Sun Abdlwareth A. Almoneafy M. Auwal Hassan Ahmed Elshakh Bin Li Guan-Lin Xie 《European journal of plant pathology / European Foundation for Plant Pathology》2014,138(4):819-834
The study presents the first report on biocontrol of brown sheath rot disease of rice caused by Pseudomonas fuscovaginae using rhizo-bacterial isolate Bacillus amyloliquefaciens Bk7. Four potential bioactive antagonists were selected from 120 Bacillus isolates. Results obtained from in vitro laboratory assay showed that rhizosphere bacterial strain Bk7 and its metabolites significantly suppressed the growth of Pseudomonas fuscovaginae with 93 % efficacy. In glasshouse experiments, strain Bk7 exhibited biocontrol efficacy of 76.6 % by reducing the disease incidence to 16.9 %, compared to 72.8 % observed in control treatment. In addition, the isolate Bk7 showed the growth promotion efficacy of plant height (GPE, 46.4 %) and fresh weight (GPE, 84.3 %). Characterization of isolate Bk7 revealed its strong capability for biofilm formation, inorganic phosphate solubilization and production of high amounts of Indole-3 acetic acid, siderophores and ammonia in vitro. Results obtained from multiplex PCR assay confirmed the presence of five lipopeptide biosynthetic gene markers (srfAA, fenD, bmyB, bacA and ituC) in the genome of strain Bk7. Moreover, Real-time qPCR of these genes demonstrated that surfactin, iturin and bacylisin coding genes were highly expressed in response to P. fuscovaginae exposure in vitro. Rhizosphere bacterial strain Bk7 was identified as B. amyloliquefaciens strain Bk7 based on the analysis of 16S rDNA internal transcribed spacer sequences and a fatty acid methyl ester analysis. The results obtained from this study showed the potential usefulness of Bk7 as a biocontrol agent in disease control of rice brown sheath rot. 相似文献
172.
Mansoor Sarani Mostafa Oveisi Hamid Rahimian Mashhadi Hassan Alizade Jose Luise Gonzalez‐Andujar 《Weed Biology and Management》2014,14(3):198-208
Field experiments were conducted in Iran in order to determine the interactions between the tillage system and crop rotation on weed seedling populations and crop yields from 2002 to 2005. No tillage, shallow tillage and deep tillage were the main plots and three crop sequences comprising continuous wheat (W‐W), wheat–canola–wheat–canola (C‐W) and wheat–safflower–wheat–safflower (S‐W) were the subplots. Bromus japonicus, Carthumus lanatus, Polygonum aviculare, Lolium temulentum and Avena ludoviciana were found to be the dominant species. The initial weed population in 2002 was estimated at 65 seedlings per m2 and B. japonicus (~35 seedlings per m2) was the most abundant species, followed by A. ludoviciana and L. temulentum. The dominant weed species mostly did not favor the combination of S‐W and C‐W with any tillage type. For the B. japonicus population, S‐W in combination with moldboard plowing indicated the lowest seedling population. In conclusion, the crop sequence in combination with tillage would help to control troublesome weed species. Safflower and canola were determined to be effective in reducing the grass weeds. The inclusion of these crops in rotation also increased the total revenue of the cropping systems because of the higher sale price of canola and safflower. 相似文献
173.
V. A. Taube M. E. Neu Y. Hassan J. Verspohl M. Beyerbach J. Kamphues 《Journal of animal physiology and animal nutrition》2009,93(3):350-358
The aim of this study was to examine whether and to what extent the addition of potassium diformate (pdf) or free organic acids (fpa) to the diet and the grinding intensity might affect the course of infection and the passage of orally applied Salmonella and Escherichia coli in pigs. Experiments were carried out using 80 reared piglets allotted to four groups. Pigs were fed pelleted diets ad libitum (except during a 15 h feed‐withholding‐period before infection). The control diet contained finely ground cereals (2 mm screen). To two test diets (also finely ground) 1.2% pdf, 0.9% organic acids (75% formic and 25% propionic acid, fpa) respectively were added. The fourth diet (without acids) was based on coarsely ground cereals (6‐mm screen). After experimental infection alternately with S. Derby or E. coli, the course of infection was examined (rectal swab technique). Pigs were sacrificed 4–5 h after a further oral application of ~109–1010 CFU S. Derby or E. coli to determine the counts of Salmonella or E. coli in chyme (classical culture methods). Adding pdf or fpa to the diet led to reduced Salmonella shedding and resulted in significantly lower counts of Salmonella and E. coli in the stomach content indicating an improved efficacy of the stomach barrier. In the distal parts of the digestive tract, the effect was less obvious concerning counts of E. coli, whereas counts of Salmonella were reduced markedly as well. The diet based on coarsely ground cereals failed to demonstrate positive effects concerning infection and passage of orally applied bacteria as well, but this diet was also pelleted and showed unintentionally, comparable amounts of fine particles. Results obtained in this study allow the recommendation of using pdf or organic acids as additives when dietary measures against Salmonella or E. coli in pigs are required. 相似文献
174.
Three hundreds, 21 d-old slow-growing chicks were randomly divided among 5 treatments, of 5 replicates each. Each replicate
contained 12 unsexed chicks housed in (1 × 1) a floor pen. A group was kept under thermoneutral condition at 28 ± 4°C and
RH was 55 ± 3% during 21–84 d of age (positive control) and fed corn-soybean meal diet. The other four groups were kept for
three successive days per week under heat stress (HS) at 38 ± 1.4°C and 49 ± 2% RH from 12.00 to 16.00 pm. Chicks in HS treatments
were fed corn-soybean meal diet without (negative control) or with 250 mg AA/kg diet and Bet at 0.5 and 1 g/kg diet. HS decreased
productive performance, increased (P < 0.05) meat dry matter, plasma triglyceride and serum calcium whereas decreased (P > 0.05) plasma glucose, serum total protein and water holding capacity (WHC) of meat. AA and 1 g of Bet/kg diet was equally
potent for partial relief (P < 0.05) of the negative effect of HS on growth, increased (P < 0.05) feed intake, protein digestibility (P < 0.05), dressing out percentage, liver and giblets, whilst improved (P < 0.05) feed conversion ratio (FCR). Also, a complete recovery from the negative effect (P < 0.05) of HS shown on plasma glucose and partial recovery (P < 0.05) observed in total protein, triglyceride, blood pH, packed cell volume (PCV), hemoglobin (Hgb), rectal temperature
(RT) and respiration rate (RR) and improved humoral immune competence to sheep red blood cell (SBRCs) test. 相似文献
175.
176.
Vegetative propagation of Aesculus indica through stem cuttings treated with plant growth regulators
Cuttage propagation of Aesculus indica was tested by treatments with different concentrations of indole-3-acetic acid (IAA) @ 2000, 4000 (ppm), indolebutyric acid
(IBA) @ 2000, 4000 (ppm) and naphthlcetic acid (NAA) @ 2000, 4000 (ppm) in dry formulation in the Forest Nursery, Faculty
of Forestry, SKUAST-K, Shalimar. The cuttings treated with IBA @ 4000 ppm and IBA @ 2000 ppm had a sprouting rate of 75% and
50%, respectively, which was significantly higher than that of control and other treatments. The highest rooting rate (50%)
was recorded in the cuttings with the application of IBA @ 4000 ppm. The cuttings treated with IBA @ 2000 ppm had 25% rooting
rate. All other treatments along with control (talc powder) failed to induce rooting. It was concluded that IBA @ 4000 ppm
was a better-applied concentration for vegetative propagation of A. indica under Kashmir conditions.
Biography: Mumtaz Majeed (1980– ), male, post graduate in Faculty of Forestry, Sher-e-Kashmir University of Agricultural Science
& Technology, Shalimar, Srinagar - 191 121, J&K, India. 相似文献
177.
Modern nursery methods of seedling production in different sized root trainers,were compared by raising seedlings of Pinus wallichiana involving costs incurred and benefits received. In order to provide a common basis for the comparisons,the study involved the raising of 1000 seedlings annually on a continuous basis for seven years. A relative economic analysis of raising P. wallichiana seedlings in 300,150 and 100 cm3 root trainers was carried out and we estimated that the root trainers of 300 cm3 capacity... 相似文献
178.
As part of the Sino-Pak trans-boundary cooperation for conservation and sustainable development in Pamir border region,World Wild Fund (WWF)-Pakistan conducted a preliminary social,economic and ecological survey in the Shimshal-Pamir Lakes area in July 2009.The purpose of the study was to explore potentials and opportunities for future collaborative conservation of some species,habitats and high altitude ecosystems in the border region between China and Pakistan.The two-week herpetological study in the Shimshal Pamir area of Khunjerab National Park (KNP) along Pakistan-China border was an integral part of the survey,conducted exclu-sively to document reptilian fauna with a special emphasis on investigating their occurrence,distribution and status in the study area.Field investigations were performed during daytime when it was hot enough and reptiles were active,basking or feeding.A total of 15 specimens belonging to four species of the Agamidae family were captured by striking stones and beating bushes with sticks.Collected specimens were preserved using 10% formalin solution,tagged with field information and stored in Zoological Survey Department,Karachi for future reference.Laboratory investigations were carried out for pholidosic counts and morphometric measurements.A detailed review of relevant literature,habitat characteristics and laboratory investigations revealed the occurrence of Laudakia himalayana,L.pakistanica,L.tuberculata and L.badakhshana at 4,082 m,4,172 m,4,005 m and 4,240 m asl,respectively,which are much higher altitudes as compared to the previously reported heights of 3,353 m,3,200 m,2,500 m and 2,400 m asl.The terrain offers a variety of ecological barriers,in the form of fast and freezing running waters and massive glaciers with peculiar harsh climatic conditions prevailing for nine months of the year,which restricts species migration and thus increases endemism.Although one of the four species recorded from the study area,i.e.L.pakistanica is endemic to Pakistan,L.tuberculata and L.badakhshana are new records from Shimshal,Pakistan,so a detailed investigation is suggested for further herpetological records from the study area. 相似文献
179.
Sara Mola Ali Abasiyan Hassan Towfighi 《Communications in Soil Science and Plant Analysis》2018,49(6):675-688
Potassium (K+) and nitrogen [N, as the form of ammonium (NH4+)] are major nutrients for plant growth. Although there have been a number of studies on the kinetic fixation of potassium and ammonium ions in soils and clays, however, investigations on the kinetics of competitive fixation of these ions have been few, if any, especially by taking into account silt component of the soils. In this study, the kinetics of potassium and ammonium fixation were examined in the silt components of several soil samples. The results revealed that considerable amounts of K+ and in lesser amounts, NH4+ ions were fixed by silt components of the soils. Potassium fixation was strongly preferred over ammonium. To describe the fixation kinetics, seven mathematically models were evaluated. A comparison of the models showed that pseudo-second-order equation properly described the fixation of these ions by the silt components. 相似文献
180.
Samina Khalid Aman Ullah Malik Zora Singh Sami Ullah Basharat Ali Saleem Omer Hafeez Malik 《Journal of plant nutrition》2018,41(14):1786-1797
An understanding of variation in fruit quality in relation to tree age can help understand the issue of poor fruit quality in young orchards; however, limited information is available on the citrus fruit. In this study, the endogenous nutritional status in rind, rag, and leaves; pectin status in rind and rag; and anatomical fruit growth parameter in rind tissues were studied in ‘Kinnow’ mandarins fruit during their development on trees from three age (6-, 18-, and 35-year-old) groups. In older (35-year-old) trees, rind, rag, and leaf nitrogen (N), phosphorus (P), and potassium (K) concentrations were superior. In fruit from all tree age groups, total pectin and protopectin reduced; however water-soluble pectin (WSP) improved. In rind tissues harvested from young (6-year-old) trees, cell density was more while cell size was less. In all tree age groups, cell density in rind tissues correlated negatively with rind WSP. 相似文献