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191.
Soil N transformation was investigated using15N dilution method along a slope on a conifer plantation forest. Although there was no significant difference in the net N
mineralization rates by laboratory incubation, net nitrification rates increased downslope. Gross N transformation by15N dilution method showed a distinct difference not only on the rates, but also on the main process between the lower and the
upper of the slope. Half of minelarized N was immobilized and the other half was left in NH
4
+
pool at the upper part of the slope, while all of mineralized N was used for immobilization or nitrification and NH
4
+
pool decreased at the lower of the slope. Soil N transformations were classified into two groups: one was shown below 773
m and the other was shown above 782 m. The incubation with nitrification inhibitor showed that nitrification was mainly conducted
by autotrophs irrespective of the position of the slope. Microbial biomass and microbial C/N were similar among the sites.
However, the gross mineralization rate was higher below 773 m than above 782 m under similar respiration rates. This suggests
that the substrate quality may be one of the controlling factors for soil N transformation. Extractable organic C/N was similar
to microbial C/N at the lower of the slope. It indicated that the substrate was more decomposable below 773 m. It is considered
that soil N transformation is affected by topographical gradient of moisture and nutrient which makes plant growth and decomposition
rate different. 相似文献
192.
Yamaji Y Seki S Matsukawa K Koshimoto C Kasai M Edashige K 《The Journal of reproduction and development》2011,57(3):403-408
Previously, we showed that the exogenous expression of aquaporin 3 (AQP3), an aquaglyceroporin, improved the tolerance of mouse oocytes to vitrification with a glycerol-based solution. In the present study, we examined conditions suitable for the expression of AQP3 and the ability of vitrified oocytes to develop in vitro and in vivo after fertilization. After only partial remove of cumulus cells, immature mouse oocytes (germinal vesicle stage) were injected with 5, 10 or 20 pg of AQP3 cRNA and cultured for 12 h for maturation. When matured oocytes were vitrified with a glycerol-based solution, 57-61% survived regardless of the amount of cRNA injected (5-20 pg). By contrast, no oocytes injected with water (control) survived. When the zona pellucida was removed from the vitrified oocytes and the oocytes were then fertilized in vitro and cultured, the proportions that were fertilized and developed into blastocysts were higher when the amount of cRNA injected was 5 pg than 10-20 pg. When 16 blastocysts were transferred to a pseudopregnant mouse, 5 developed to term, demonstrating that oocytes vitrified after injection of AQP3 cRNA retained the ability to develop to term. The water-permeability of cRNA-injected oocytes was higher than that of control oocytes from the maturing stage to the 1-cell zygote stage, whereas glycerol-permeability was higher only at metaphase II. This indicates that AQP3 was expressed for a relatively short period of time. These results suggest that the transient expression of water/cryoprotectant channels is effective for cryopreserving cells that have low membrane-permeability, such as mammalian oocytes. 相似文献
193.
Matsuura K Kuroda Y Yamashita K Funahashi H 《The Journal of reproduction and development》2011,57(1):163-167
Motile porcine sperms adhere to hydrophilic materials such as glass and plastics. The adsorption of sperms to a hydrophobic poly(dimethylsiloxane) (PDMS) membrane is less compared with that to glass. We investigated the linear velocity (LV) and amplitude of lateral head displacement (ALHD) of motile porcine sperm on glass and PDMS preparations using computer-assisted sperm analysis (CASA). Significant decreases were observed in the 15-min LV (P<0.05) and ALHD (P<0.05) in motile porcine sperm on glass preparations compared with those on PDMS preparations. These differences were due to adsorption of the head and/or neck to hydrophilic substrates. Because of the elasticity of PDMS, we propose that a PDMS membrane should be used for CASA. To investigate the dynamics of motile porcine sperms with microfluidics, we do not recommend plasma treatment to bond PDMS and glass in the microchannel preparation; instead, we suggest that a PDMS molding process without plasma treatment be used for preparation of microfluidic channels. 相似文献
194.
195.
Hideaki Shibata Rieko Urakawa Hiroto Toda Yoshiyuki Inagaki Ryunosuke Tateno Keisuke Koba Asami Nakanishi Karibu Fukuzawa Ayaka Yamasaki 《Journal of Forest Research》2011,16(5):374-385
Net nitrogen transformation was investigated under different climate conditions by soil transplantation and in situ incubation
of forest surface soils using the resin-core method. Selected conditions were considered to reflect those of the natural climate
gradient in the Japanese archipelago. Study sites were established in natural forests in northern Hokkaido (Uryu), northern
Kanto (Kusaki), central Kinki (Kamigamo), and southern Kyushu (Takakuma), representing the northernmost to the southernmost
island regions of Japan. Field experiments comparing soils incubated at “native” and “transplanted” sites were conducted from
June 2008 to May 2009. Net production, accumulation, and leaching of soil ammonium (NH4
+) and nitrate (NO3
−) were measured at each of the sites during the growing season (June–October), the dormant season (November–May), and throughout
the year. Net nitrate production was highest in Kusaki soil, especially during the growing season, whereas net ammonium production
was highest in Uryu soil, the coldest site, especially during the dormant season. Net nitrate production increased significantly
in soils transplanted to a warmer climate during the growing season. However, net ammonium production increased in soils transplanted
to colder climates during the dormant season. These findings indicate that, with the exception of the infertile soil samples
from Kamigamo, the range of natural climates in Japan has a significant effect on nitrogen availability in surface soil. In
addition, the original characteristics of the nitrogen cycle of the surface soil from each native site were retained, even
when marked changes in soil temperature (approximately 8°C) occurred after transplantation. 相似文献
196.
Khounsaknalath SITHYPHONE Mitsuyasu YABE Hiroshi HORITA Keisuke HAYASHI Tomiko FUMITA Yuji SHIOTSUKA Tetsuji ETOH Fumio EBARA Olavanh SAMADMANIVONG Jochen WEGNER Takafumi GOTOH 《Animal Science Journal》2011,82(2):352-359
The objective of this article is to compare feed cost, palatability and environmental impacts among feeding systems of high concentrate (HC), high hay (HH) and grass‐only‐fed (Gof) groups. Feed cost was the sum of costs paid for feed intake times the price of feed per kilogram. Palatability was measured by a panel taste test using HH and Gof beef and analyzed for differences. Environmental impacts were calculated based on 1 kg of Japanese beef yield of CO2 equivalents (eq) and animal end weights at each feeding stage. Results showed that the HH and Gof feeding systems could significantly reduce feed costs by approximately 60% and 78%, respectively, from the HC. In the panel taste test, 50% and 47.50% of panelists indicated that HH beef was ‘extremely delicious’ and ‘acceptable,’ respectively, while 15% indicated that Gof beef was ‘extremely delicious’; 62.50% indicated that Gof beef was ‘acceptable.’ Environmental impacts of each feeding system in terms of CO2 equivalents (eq) were 9.32, 6.10 and 2.04 tonnes of eq for the HC, HH and Gof, respectively. The HH was an economical system that produced moderate impacts on the environment and had impressive taste. 相似文献
197.
198.
Aoi T Yae K Nakagawa M Ichisaka T Okita K Takahashi K Chiba T Yamanaka S 《Science (New York, N.Y.)》2008,321(5889):699-702
199.
200.
ABSTRACT: A molecular approach was adopted to investigate the natural diets of palinurid and scyllarid lobster phyllosoma larvae. The central domain of the 18S rDNA gene was amplified using nested polymerase chain reaction (PCR) and genomic DNA extracted from the larval hepatopancreas. The resulting 18S rDNA clones were screened using restriction fragment length polymorphism (RFLP) analysis, and then FASTA homology search and phylogenetic analysis were performed on the nucleotide sequences to identify the source of the eukaryotic organisms. The feasibility of this method was confirmed using the laboratory-reared phyllosoma larvae of the Japanese spiny lobster Panulirus japonicus that were fed either with common mussel Mytilus edulis gonads or with Artemia nauplii exclusively. Among the 804 clones isolated from five wild-caught mid- to late-stage phyllosoma larvae (three palinurids and two scyllarids), 0–132 clones per sample possessed restriction profiles distinct from those of the hosts. The Cnidaria and Urochordata DNA were identified from both the palinurid and the scyllarid larvae, which were thought to be prey animals for the mid- to late-stage phyllosoma larvae. 相似文献