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301.
Farmers are using skimming wells tosupplement their canal deliveries. Toensure sustainable groundwater extraction,proper design and operational guidelinesfor these skimming wells are required. Thestarting point of such guidelines is tolook at farmers' existing groundwaterextraction practices, their extent andassociated problems. For this purpose, afield survey was conducted in the IndusBasin of Pakistan. Participatory ruralappraisal identified several design andoperational problems with farmers' skimmingwells. These include; depth of well,number of strainers, horizontaldistance of strainers, priming, water quality, sand in pumped water,and reduction in well discharge withtime. To investigate these problems,diagnostic analysis was carried out. A testborehole was drilled to get water samplesalong the aquifer depth during drilling.The depth of well was then decided on thebasis of these water quality analyses. Todecide the number of strainers, a pumpingtest was conducted at test borehole toestimate the contribution of individualstrainer and then the numbers wereincreased according to the desireddischarge. Similarly, placing non-returnvalve between blind pipe and strainersolved the priming problem. Operating wellsintermittently rather than continuouslysolved the problems of water quality andreduction in well discharge. The systematicapproach adopted in the study helped thefarmers to rectify the problems.  相似文献   
302.
303.
The interrelationships among bean productivity, prevalence of pathogens in roots, seeds and soil, and root rot disease were described at the pod maturity stage in 13 commercial fields. The soil population and frequency of pathogens isolated from seeds varied by pathogen species and field location. Fusarium solani was the most prevalent fungus isolated from bean seeds and field soil compared to Rhizoctonia solani, Macrophomina phaseolina and F. oxysporum. Principal component analysis revealed that the first component explaining 32% of the total variance was correlated with the root rot index. PC1 was more strongly linked to root and seed infections in comparison with soil populations of pathogens. Based on a correlation between PC2 (accounting for 23% of the total variance) and the number of seeds per bean plant, charcoal, Fusarium and Rhizoctonia root rots were recognized as more important determinants of seed losses to root rot disease. There were correlations among the major pathogens infecting either roots or seeds of beans. These findings provide useful information for future experimental plans to optimize management strategies for bean root rots.  相似文献   
304.
Effects of grain source and dietary oil supplement on dry matter intake (DMI), feeding, chewing behavior, and production performance of lactating dairy cows were evaluated using eight multiparous Holstein cows (77±22.1 days in milk; mean±SD) in a duplicated 4×4 Latin square design with a 2×2 factorial arrangement of treatments. Experimental diets contained either ground barley or ground corn supplemented with either fish oil or soybean oil at 2% of dietary dry matter (DM). Geometric mean particle size of dietary treatments was 4.1 mm. Dry matter intake tended (P=0.09) to be greater for barley- vs. corn-based diets (23.2 vs. 22.3 kg/d), but was reduced for the fish oil compared to soybean oil supplemented diets (21.1 vs. 24.3 kg/d; P<0.001). This reduction in DMI was attributed to smaller meal size (1.24 vs. 1.55 kg of DM; P=0.004) and slower eating rate (0.082 vs. 0.098 kg of DM/min; P<0.001) for fish oil compared to soybean oil supplemented diets. Main treatment effects interacted (P=0.005) for DMI of particles retained on 19 mm sieve but not for sorting index. Eating rate (0.090 kg of DM/min) was similar between barley- and corn-based diets, however, rumination time was greater for barley- compared to corn-based diets as result of longer rumination bout duration (32.5 vs. 28.5 min/bout; P=0.01). Barley- compared to corn-based diets increased total chewing time by 71 min (709 vs. 638 min) for cows fed fish oil, but not for cows fed soybean oil. Grain source did not affect milk yield or milk composition. Compared to soybean oil, fish oil negatively affected milk yield (40.4 vs. 43.4 kg/d; P=0.01), and thereby, both milk fat (0.91 vs. 1.26 kg/d; P<0.001) and protein (1.23 vs. 1.33 kg/d; P=0.007) production. However, feed efficiency (milk yield/DMI) was greater in fish oil compared to soybean oil supplemented diets (1.94 vs. 1.80; P=0.003). Results indicated that grain source and oil supplement can interact to affect feeding and chewing behavior, but not lactational performance of lactating cows.  相似文献   
305.
This study investigated physiological effects of pistachio by‐products silage (PBPS) substituted in Holstein male calves diets and its effects on the growth performance. Twenty‐four Holstein male calves (4–5 months of age and 155.6 ± 13.5 kg BW) were randomly assigned to one of four experimental diets (n = 6); contained 0%, 6%, 12% and 18% of PBPS (DM basis) respectively. During a 6‐month experiment, dry matter intake (DMI) and weight gain were recorded and blood and urine samples were collected at different times. Results showed that mean DMI was not affected by different levels of PBPS in diets. But the calves fed 6% PBPS had the highest average daily gain (p < 0.05) and the lowest feed conversion ratio (p < 0.05). The calves fed 12% and 18% PBPS had lower albumin, white blood cell, haemoglobin and packed cell volume (p < 0.05) than those fed other diets. However, other serum metabolites, complete blood count (CBC), insulin and liver enzymes were not affected by the experimental diets. The long‐term feeding of PBPS at different levels had no significant effect (p > 0.05) on pH, specific gravity, the number of white and red blood cells and epithelial cells count in urine. The animals did not show any symptom of illness or toxicity during the experimental period and all of the blood and urine parameters were in a normal range. It was concluded that substitution of PBPS up to 18% of the total diet that provide up to 18.2 g/kg DM total tannin had no adverse effects for Holstein male calves.  相似文献   
306.
Pasteurella multocida serotype B:2 is the causative agent of haemorrhagic septicaemia (HS), a fatal disease of cattle and buffaloes. As a step towards the identification of individual antigens that may protect against HS, proteins present in a sonicated cell extract (SCE) and outer-membrane protein (OMP) preparation of a wild-type P. multocida serotype B:2 were investigated by immunoblotting with sera from calves which had been protected against challenge with a virulent strain of P. multocida B:2 by vaccination with a live-attenuated aroA derivative of the challenge strain. Five proteins in SCE, of approximately 50, 37, 30, 26 and 16 kDa, were recognised by the sera. In an OMP preparation, two bands, at 37 and 50 kDa, were recognised as strongly immunogenic. Mass spectrometry analysis of proteins corresponding in size to those detected by immunoblotting identified the 37 kDa band as OmpA, but the band at 50 kDa was not identified with certainty. A major 30 kDa OMP, identified as OmpH, was not strongly immunogenic.  相似文献   
307.
The objective of the study was to examine the effects of biofloc technology on the muscle proteome of Litopenaeus vannamei. Two biofloc treatments and one control were compared: biofloc‐based tanks under zero‐water exchange fed with 150 g/kg crude protein (BF15), or with 250 g/kg crude protein (BF25) diets, and clear water tanks with 50% of daily water exchange stocked with shrimp fed with similar amount of a 250 g/kg crude protein diet, referred to as control. The shrimp (5.28 ± 0.42 g) were divided into the 300‐L fibreglass tanks (water volume of 200 L) at a density of 35 shrimp per tank and were cultured for 35 days. The biofloc groups displayed better growth and survival compared to the control. The muscle tissue from the control and BF25 groups was subjected to proteomic analysis. Lactate dehydrogenase, enolase, arginine kinase, mitochondrial ATP synthase subunit alpha, mitochondrial ATPase inhibitor factor 1 precursor, serpin 3 and myeloid differentiation factor 88 had an increased abundance in the BF25 group, while myosin heavy chain type 1 and myosin heavy chain type 2 showed a decreased abundance. The results indicate that biofloc technology could alter the expression of proteins involved in structure, metabolism and immune status of cultured shrimp.  相似文献   
308.
The availability of monosex populations of caviar‐producing female sturgeon would considerably enhance the economic viability of domestic caviar production systems. However, it is not possible to distinguish males from females by morphological characters at larval, juvenile and even adult stages. The mechanism of sex determination in sturgeons is poorly understood, and to date no sex‐specific markers in sturgeon have been reported. This review concentrates on the methodologies used to elucidate the mode of sex determination in sturgeon species and provides information on the molecular tools used to determine genetic sex markers.  相似文献   
309.
A study was conducted to investigate the effects of dietary oligofructose (1, 2 and 3%) on the blood profiles of beluga (Huso huso) juveniles (18.77 ± 0.76 g) compared to fish fed an un-supplemented diet. After 7 weeks of feeding on the experimental diets, haematological parameters, metabolic products (cholesterol, glucose and total protein) and serum enzymes (lactate dehydrogenase, alkaline phosphatase, alanine aminotransferase and aspartate aminotransferase) were measured. Compared to the control group (0% oligofructose), dietary oligofructose had no effect on red blood cell counts (RBC), mean corpuscular volume (MCV), mean cellular haemoglobin (MCH) or mean cell haemoglobin concentration (MCHC) (P > 0.05). However, haemoglobin (Hb) concentration, leucocyte (WBC) levels and the proportion of lymphocytes were significantly higher (P > 0.05) in the 2% oligofructose fed fish than in the 3% oligofructose fed fish. Additionally, haematocrit (Hct) values (P = 0.049) and the proportion of lymphocytes (P ≤ 0.01) were significantly higher in the 2% oligofructose group than in the control group. Although serum glucose and total protein remained unaffected, serum cholesterol was significantly lower in the 2% oligofructose group than in the control and 3% oligofructose group (P < 0.05). The results of the present study showed that oligofructose had no significant effects on serum lactate dehydrogenase, alkaline phosphatase, alanine aminotransferase and aspartate aminotransferase. These results indicate that fish blood profiles could be affected by prebiotics, which should be taken into account in future studies.  相似文献   
310.
Emission of methyl isothiocyanate (MITC) from fields treated with metam‐sodium (sodium N‐methyldithiocarbamate) is a potential environmental and human safety hazard. Concentrations of MITC at three heights above four arable fields were measured following the application of metam‐sodium at a rate of 480 litre ha−1 (166 kg AI ha−1). Two of these fields were treated by injection into a center‐pivot irrigation system (chemigation), while in the other two fields the fumigant was applied through injection directly into the soil. Generally, higher MITC air concentrations were observed above chemigated than above injected fields. Maximum MITC air concentrations were 11.2 and 7.4 µg m−3 recorded 10 cm above ground 6–8 h following application and the minimum concentrations were 0.7 and 0.2 µg m−3 observed at 200 cm 30–35 h after application above chemigated and injected fields, respectively. The estimated MITC respiratory exposure a worker might encounter during the re‐entry period ranged between 1.37 and 0.03 mg day−1 in chemigated fields and between 0.35 and 0.02 mg day−1 in the injected fields. These results suggest that application of the fumigant through injection reduced MITC volatilization losses in comparison with the chemigation method, thus posing a relatively lower risk of exposure to MITC emissions. © 2000 Society of Chemical Industry  相似文献   
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