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131.
The purpose of this study was to investigate the influence of soil geochemistry on the concentrations of Ca, K, Mg, P, Co, Ni, Zn, Mn, Cu, and Fe in cabbage (Brassica oleracea L. var. capitata) grown on acid sulfate (AS) soils in Western Finland. A total of 11 topsoil (0–20 cm) and corresponding cabbage samples and three whole‐soil profiles (≈ 0–260 cm) were collected on three agricultural fields. The concentrations of Co and Zn in cabbage were correlated with the NH4Ac‐extractable (easily available) concentrations in the topsoil, indicating that the uptake of these elements in cabbage is largely governed by soil geochemistry. Yet, the concentrations of Co and Zn in cabbage were not in general elevated relative to that of Finnish average values, although some AS soils showed enriched concentrations of these metals in the soil and cabbage. Significant geochemical differences (e.g., oxidation depth, organic‐matter and S content, pH) were observed among the studied AS soils, while, on the other hand, the concentrations of Ca, K, Mg, P, Ni, Mn, Cu, and Fe in cabbage were relatively similar. The hydroxylamine‐extractable concentrations of these elements in the topsoil were not correlated to those in cabbage, suggesting that uptake is not governed by the oxide‐bound fraction of these elements in the soil. Similarly, the easily available concentrations of Ca, P, Ni, Mn, Cu, and Fe in the topsoil were not correlated to those in cabbage, indicating that uptake is independent of the easily available concentrations in the soil. Hence, it is suggested that cabbage can regulate and thus optimize its concentrations of Ca, P, Ni, Mn, Cu, and Fe. Oxidation depth affected neither the easily available concentrations of Co, Ni, Zn, and Mn in the topsoil nor the concentrations in cabbage. However, the subsoil with a lower oxidation depth, which is to a smaller extent affected by leaching, may partly be enriched in these metals. Nevertheless, these showed no increased concentrations in cabbage. Based on these findings, it is suggested that the large amounts of metals mobilized in AS soils are easily lost to drains, subsequently contaminating nearby waterways and estuaries whereas they are only partly enriched in cabbage and other previously studied crops (oat).  相似文献   
132.
Poxvirus epidemics occur almost every year and cause significant economic losses for small-scale animal producers in Turkey. In this study, the causative agent of the most recent epidemic in Central Anatolia was detected in clinical samples using electron microscopy (EM) and amplified using an in house polymerase chain reaction procedure for the first time. Additionally, the aetiological agent was isolated from a sheep and identified using EM and PCR.  相似文献   
133.
1. Developmental stability of bilaterally symmetrical traits was measured in two fast (G1 and G2) and one slower growing (G3) broiler stocks when conditioned (chicks exposed to 36 degrees C for 24 h at 5 d of age) or food restricted (food withdrawn 2 h before the hot period and chicks fed between 17.00 and 08.00 h) during heat stress administered daily from 28 to 49 d of age. 2. Length of face, length, width and weight of shanks, weights of P. major and P. minor muscles, and weights of lung and caeca were chosen as bilateral traits representative of skeletal, muscle, respiratory and digestive systems. 3. Development of skeletal bilateral traits was affected primarily by genotype and sex. The heart:lung ratio decreased with conditioning in stocks G1 and G2 at 21 d. Face length, shank length and shank weight exhibited antisymmetry, whereas shank width and weights of P. minor, lung and caeca exhibited fluctuating asymmetry and antisymmetry. For P. major weight, there was directional asymmetry. 4. In general, relative asymmetry of skeletal traits was lower than for traits associated with muscle and with respiratory and digestive systems. Relative asymmetry of P. major weight was lower in conditioned and G3 broilers than in their respective counterparts. 5. If relative asymmetry is a valid indicator, item heat stress may be less in slower growing and conditioned broilers.  相似文献   
134.
1. This study was to determine the effects of strain, age of the maternal flock and sex on morphological characteristics and composition of tibial bone of broilers from hatch to 48 d of age. 2. A total of 600 chicks was obtained from 2 strains of broiler breeder flocks (150/chicks/strain/maternal age). Maternal flock age was classified as young (32 to 35 weeks of age) or old (56 to 58 weeks of age). Birds were reared under standard feeding and lighting regimes. 3. On day 1, 16, 32 and 48, twelve birds were selected at random from each maternal group, strain and sex and killed. The wet bone weight and volume were measured. Morphological characteristics of tibia were determined using radiography. Bone breaking strength was tested. Tibia dry matter, ash content, mineral density and collagen level were determined. 4. A quadratic increase occurred with increase in age of broilers for all variables, except proximal width, medial cortex thickness and distal condyle width which increased in a linear manner. 5. Maternal age had a significant effect only on the variably measured at the time of hatch. On day of hatch bone weight, ash content and bone volume were affected by maternal age, but the extent of this also depended on the strain. 6. The differences observed between strains for bone anatomy and bone mineralisation during the rapid growth period of 16 d were not significant at later ages, with the exception of bone volume. Differences between sexes were evident from 16 to 49 d of age with females having lower values.  相似文献   
135.
As part of a multidisciplinary study performed for the National Commission on Air Quality, the phenomena of atmospheric transport and the removal of SO2 and SO4 ? during a major regional sulfate episode (the period July 18–25, 1978 in the eastern U.S.) had been examined. The main objective of this study was the evaluation and the quantification of varying source/receptor relationships under atmospheric conditions conducive to long-range transport of fine particulate matter. In the case study presented here, air mass trajectories were obtained using the numerical NMC trajectory predictions and the results of the isobaric trajectory computations at the 850 mb level. The effects of alternative regional SO2 emission reduction scenarios on the predicted ambient SO2 and SO4 ? concentrations were also investigated using the new modeling methods that were specifically developed for this purpose.  相似文献   
136.
Average ozone concentrations at a remote site in the Uludag Mountain of Northwestern Turkey was 29 ppb for a 12 month period. Only 11% of the time 1-h average values exceed 50 ppb. The US Air Quality Standard of 0.12 ppm was not exceeded. The diurnal variations of O3 and NO2 were 27 and 2.3 ppb respectively, during summer 1993, indicating the impact of urban and industrial sources. Highest O3 concentrations were observed under southerly and northerly winds, suggestive of the transport of photochemically produced oxidants from Bursa city and industries and a power plant located downwind of the sampling site.  相似文献   
137.
Changes in the soil chemical environment can be expected to increase the leaching of trace metals bound in soils. In this study the mobility of trace metals was monitored in a column experiment for two contaminated urban soils. Four different treatments were used (i.e. rain, acid rain, salt and bark). Leachates were analysed for pH, dissolved organic carbon (DOC) and for seven trace metals (cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), nickel (Ni), lead (Pb) and zinc (Zn)). The salt treatment produced the lowest pH values (between 5 and 6) in the effluent whereas the DOC concentration was largest in the bark treatment (40–140 mg L?1) and smallest in the salt and acid treatments (7–40 mg L?1). Cadmium, Ni and Zn were mainly mobilised in the salt treatment, whereas the bark treatments produced the highest concentrations of Cu and Pb. The concentrations of Cu, Cr, and Hg were strongly correlated with DOC (r 2?=?0.90, 0.91 and 0.96, respectively). A multi-surface geochemical model (SHM-DLM) produced values for metal dissolution that were usually of the correct magnitude. For Pb, however, the model was not successful indicating that the retention of this metal was stronger than assumed in the model. For all metals, the SHM-DLM model predicted that soil organic matter was the most important sorbent, although for Pb and Cr(III) ferrihydrite was also important and accounted for between 15 and 50% of the binding. The results confirm the central role of DOC for the mobilization of Cu, Cr, Hg and Pb in contaminated soils.  相似文献   
138.
The conversion factor between C2H2 reduction and N2 fixation was studied in two soils. In one study small cores from (he two soils were drained to three water tensions: 0.20, 1.17 and 4.89 kPa. At each tension the N2ase activity was measured with both O.1 aim 15N2 and 0.1 aim C2H2. The conversion factor was different for the two soils. 1.0 and 3.1. respectively. The water content had no influence on the value of the conversion factor in this first study, in which the fixation corresponded to about 1mg N m?2 day ?1 at the depth 0–3 cm.In another study glucose was added to one of the soils to enhance the N2ase activity. The activity was measured at 75 and 100% water saturation with both 0.9 atm 15N2 and 0.1 atm C2 H2. At the lower water content the conversion factor was 2.6 and at water saturation the factor was 15.7. The fixation rates were high in this study. 98 mg N m?2 day?1 at the lower water content and 42 mg at water saturation.By theoretical calculations it was shown that the concentration of dissolved N2 restricted the rate of fixation in the water-saturated samples of the second study, thus giving the high conversion factor. The critical level of N2asc activity in water-saturated soil, above which the actual C2H2 to N2-ratio will be higher than usual, was estimated to about 10mg Nm 2day?1, under the experimental conditions used in these studies.  相似文献   
139.
The objective of the present study was to examine the effect of potassium (K) fertilization and soil texture on total yield (1st and 2nd cuttings) and yield components of sweet basil (Ocimum basilicum L.) A greenhouse pot experiment was conducted in a completely randomized statistical design. Basil growth was examined in two different textured soils under three different doses of K fertilization. Generally, for the basil grown under clay soil conditions, moderate amounts of K fertilization is proposed to be sufficient if higher linalool contents are wanted. However, if the growing conditions are sandy loam in texture, it is suggested that higher doses of K be used. Results also highlighted the contribution of second cut as an important cultural practice in the cultivation of an annual basil.  相似文献   
140.
The total amount of organically bound halogens was determined in soil samples from the Palace Leas meadow hay plots, Northumberland, UK. These plots have been amended with different combinations of farmyard manure, potassium chloride, ammonium sulphate or nitrate since their establishment in 1897, resulting in, among other things, substantial pH differences between the plots. It was found that the amount of organically bound halogens increased significantly with decreasing pH. Net changes in amounts of organohalogens were also studied in soil obtained from a coniferous forest in southern Sweden. The collected soil was divided into four sets of samples, which were incubated in a climate chamber and subjected to different treatment regimes that influence soil pH. Significant changes in amounts of organically bound halogens were detected in three of the four sets of samples, resulting in significantly increasing amounts with decreasing pH. However, although the amount of organically bound halogens detected was related to soil pH in both the field and the experimental study, the net changes observed in the latter investigation were not directly related to soil pH. This shows that net changes in the amount of organically bound halogens in soil are caused by complex processes, and that further studies are needed to clarify the nature of the observed relation between soil pH and amounts of organically bound halogens.  相似文献   
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