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71.
72.
D. Kantachote I. Singleton R. Naidu N. McClure M. Megharaj 《Water, air, and soil pollution》2004,154(1-4):115-125
Bioremediation is an economically attractive option to remediate soil contaminated with DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane] and other organochlorine pesticides. However, lack of DDT bioavailability in soil presents one major obstacle to this technology particularly in soils that have been contaminated for long periods. In this work, sodium ion (Na+) was applied to a long-term DDT contaminated soil as Na+ is known to disperse clays, which would potentially release and/or expose physically protected DDT thereby enhancing DDT bioavailability. Sodium ion addition significantly increased dissolved organic carbon (DOC) levels, anaerobic bacterial numbers and the amount of DDT residues measured in soil solution. DDT transformation ranged from 95% (30—80 mg Na+ kg-1 soil) to 72% (no Na+ added) with the optimum level of DDT transformation occurring at 30 mg Na+ kg-1 soil. Higher Na+ levels repressed DDT transformation and this appeared to be related to lower DOC levels and flocculation of soils. The anaerobic incubation conditions employed (high water content) prevented DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene] production and DDD [1,1-dichloro-2,2-bis(p-chlorophenyl)ethane] was the major breakdown product formed. Overall it appeared that Na+ has potential as a cheap and safe alternative to surfactants as a method for increasing DDT transformation in contaminated soil. 相似文献
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75.
Kunkalikar SR Poojari S Arun BM Rajagopalan PA Chen TC Yeh SD Naidu RA Zehr UB Ravi KS 《Phytopathology》2011,101(3):367-376
A survey for Peanut bud necrosis virus (PBNV), Watermelon bud necrosis virus (WBNV), Capsicum chlorosis virus (CaCV), and Iris yellow spot virus (IYSV) was conducted between 2002 and 2009 in the major vegetable-growing areas in India. PBNV was documented widely in tomato and chili peppers in 14 states representing southern, north-western, north-eastern, and central regions and WBNV was predominantly detected in watermelons and cucurbits in all except north-eastern regions. In addition, the expanded host range of PBNV to watermelons and other cucurbits and WBNV to tomato and chili peppers was observed leading to natural mixed infection of the two viruses. IYSV was found in onion in southern, central, and north-eastern regions and CaCV in tomato and chili peppers in northern and southern regions, respectively. Phylogenetic analysis of the nucleocapsid gene revealed segregation of field isolates of PBNV and WBNV into two distinct subclades, whereas isolates of CaCV and IYSV each clustered into a single clade. A proposal for establishing WBNV as a distinct tospovirus species is made based on the molecular characterization of small- (S) and medium- (M) RNA segments. 相似文献
76.
Partially Molten Middle Crust Beneath Southern Tibet: Synthesis of Project INDEPTH Results 总被引:23,自引:0,他引:23
KD Nelson W Zhao LD Brown J Kuo J Che X Liu SL Klemperer Y Makovsky R Meissner J Mechie R Kind F Wenzel J Ni J Nabelek C Leshou H Tan W Wei AG Jones J Booker M Unsworth WSF Kidd M Hauck D Alsdorf A Ross M Cogan C Wu E Sandvol M Edwards 《Science (New York, N.Y.)》1996,274(5293):1684-1688
INDEPTH geophysical and geological observations imply that a partially molten midcrustal layer exists beneath southern Tibet. This partially molten layer has been produced by crustal thickening and behaves as a fluid on the time scale of Himalayan deformation. It is confined on the south by the structurally imbricated Indian crust underlying the Tethyan and High Himalaya and is underlain, apparently, by a stiff Indian mantle lid. The results suggest that during Neogene time the underthrusting Indian crust has acted as a plunger, displacing the molten middle crust to the north while at the same time contributing to this layer by melting and ductile flow. Viewed broadly, the Neogene evolution of the Himalaya is essentially a record of the southward extrusion of the partially molten middle crust underlying southern Tibet. 相似文献
77.
Piw Das Victor A. Arias E. Venkata Kambala Megharaj Mallavarapu Ravi Naidu 《Water, air, and soil pollution》2013,224(12):1-14
Perfluorooctane sulfonate (PFOS), which has numerous uses besides being an ingredient in the formulation of aqueous film-forming foams, is considered as an emerging pollutant of increasing public health and environmental concern due to recent reports of its worldwide distribution, environmental persistence and bioaccumulation potential. In an attempt to recommend a ‘risk-based’ remediation strategy, this study investigates the removal of PFOS from impacted waters and fixation of PFOS in impacted soils using a novel modified clay adsorbent (MatCARE?, patent number 2009905953). Batch adsorption tests demonstrated a much faster adsorption kinetics (only 60 min to reach equilibrium) and remarkably higher PFOS adsorption capacity (0.09 mmol g?1) of the MatCARE? compared to a commercial activated carbon (0.07 mmol g?1). Treatability studies, performed by treating the PFOS-contaminated soils with the MatCARE? (10 % w/w) and then incubating at 25 and 37 °C temperatures maintaining 60 % of the maximum water holding capacity of the soils for a period of a year, demonstrated a negligible release (water extractable) of the contaminant (only 0.5 to 0.6 %). The fixation of PFOS in soils by the new adsorbent was exothermic in nature. Soils with higher clay and organic matter content, but lower pH values, retained PFOS to a much greater extent. A cost analyses confirmed that the MatCARETM could be an economically viable option for the ‘risk-based’ remediation of PFOS in contaminated waters and soils. 相似文献
78.
Abstract AIMS: To investigate the perceived adverse effects of a particular batch of ketamine during induction of anaesthesia in sheep and to assess if any adverse effects would make intubation more difficult for the veterinary students. METHODS: Thirty adult sheep (mean bodyweight 74.5 (SD 9.4) kg) were randomly assigned to one of six groups of five sheep. Sheep in Groups A and B received I/V 0.5 mg/kg diazepam and 10 mg/kg ketamine (Ketamine Injection; Parnell Laboratories NZ Ltd, of the suspect batch); those in Groups C and D received I/V 0.5 mg/kg diazepam and 10 mg/kg ketamine (Ketalar; Hospira NZ Ltd.), and those in Groups E and F received I/V 2 μg/kg medetomidine and 2 mg/kg alphaxalone. In Groups A, C and E, intubation was by an experienced anaesthetist, and in Groups B, D and F intubation was by a veterinary student. Time from injection to successful intubation, the ease of intubation, saturation of haemoglobin with oxygen (SpO2) and partial pressure of oxygen in arterial blood (PaO2) were measured before the sheep were connected to an anaesthetic machine and allowed to breath oxygen. Times to extubation, holding its head up and standing, maximum and minimum heart rates, respiratory rates, maximal end tidal CO2, and the quality of recovery were then recorded. RESULTS: There were no measurable differences in outcomes between sheep in Groups A and B compared with C and D. Time to intubation was slightly shorter for the experienced anaesthetist than the student, but the difference was not significant. The sheep in Groups E and F took less time to recover than those in Groups A?D (p<0.05), but there were no significant differences between the groups in either the ease of induction or quality of recovery. Most sheep in Groups E and F showed minor excitatory effects, mainly at induction, which did not interfere with induction. Respiratory rates were lower in Groups E and F than Groups A?D (p<0.01), but SpO2 was higher in Groups E and F than A and B (p<0.05). CONCLUSIONS: The clinical impression that the batch of Parnell ketamine produced unexpected effects was shown to be incorrect. All the combinations produced anaesthesia that allowed intubation by the veterinary student. CLINICAL RELEVANCE: All the drug combinations produced satisfactory anaesthesia in sheep, but the alphaxaloneand medetomidine combination resulted in faster recovery. 相似文献
79.
Ishwar H. Boodi Santosh K. Pattanashetti Basavaraj D. Biradar Gopalakrishna K. Naidu Virupakshi P. Chimmad Anand Kanatti Vinod Kumar Manoj K. Debnath 《Journal of Crop Science and Biotechnology》2016,19(2):177-187
Iron deficiency chlorosis (IDC) causes a significant reduction in yield of groundnut grown in calcareous and alkaline soils in India. The main aim of the study was to assess genotypic differences for morpho-physiological parameters associated with IDC resistance across different stages and their effect on yield and its related traits. The factorial pot experiment was comprised of two major factors, i) soil-Fe status [normal-Fe, deficit-Fe], and ii) genotypes [five] with differential IDC response, constituting 10 treatments. They were assessed for five morpho-physiological parameters associated with IDC resistance across five crop growth stages and also yield and its related traits. Associations between these traits were also estimated. Under deficit-Fe conditions, IDC resistant genotypes recorded significantly lower visual chlorosis rating (VCR), higher SPAD values, active Fe, chlorophyll content, peroxidase activity, and high yield compared to susceptible ones. Between normal- to deficit-Fe soils, resistant compared to susceptible genotypes showed no change in VCR scores; a lower reduction in SPAD, chlorophyll, active Fe, peroxidase activity, and pod yield. Under deficit-Fe conditions, high yield among resistant genotypes could be attributed to higher seed weight, number of pods and haulm yield, while contrasting reduction in main stem height and number of primaries. The results indicate that for initial large-scale screening of groundnut genotypes for IDC resistance, SPAD values are most ideal while active Fe could be utilized for confirmation of identified lines. 相似文献
80.
M. A. Ayanka Wijayawardena Mallavarapu Megharaj Ravi Naidu 《Journal of Soils and Sediments》2017,17(4):1064-1072