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401.
Compositional changes of selected amino acids,organic acids,and soluble sugars in the xylem sap of N,P, or K‐deficient tomato plants
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Jwakyung Sung Yejin Lee Seongsoo Kang Sangkeun Ha Hari B. Krishnan Taek‐Keun Oh 《植物养料与土壤学杂志》2015,178(5):792-797
Xylem sap plays a major role in long‐distance transport of water, nutrients, and metabolites. However, there is little information on the behavior of metabolites in mineral‐deficient xylem sap. For this reason, the time‐dependent changes in selected metabolites (amino acids, organic acids, and soluble sugars) from tomato xylem sap in response to nitrogen (N), phosphorus (P), or potassium (K)‐deficient condition were investigated. Tomato plants (Solanum lycopersicum L.) were grown hydroponically in liquid culture under three different mineral regimes: N‐deficient [0.5 mM Ca(NO3)2 and 0.5 mM KNO3], P‐deficient (0.05 mM KH2PO4), and K‐deficient (0.5 mM KNO3), respectively. Xylem sap was collected at 10:00 am after 1, 5, 15, and 30 d, and the selected metabolites were analyzed with liquid chromatography. All N, P, or K deficiencies led to a substantial increase in metabolites in the xylem sap. The predominant amino acid in the xylem sap was glutamine and, interestingly, all mineral deficiencies resulted in a substantial amount of γ‐aminobutyric acid (GABA). Additionally, organic acids (citrate and malate) and soluble sugars were strongly increased in all mineral deficiencies, and, in particular, the level of shikimate was greatly affected by N deficiency. Based on these data, it is necessary to clearly elucidate an unknown event taking place in xylem loading in a variety of environmental impacts, and we are now studying to expand our knowledge on metabolic and proteomic responses using GC‐MS and LC‐MS. 相似文献
402.
Profiles development of the melt spinning process of poly(trimethylene terephthalate) (PTT) was simulated by a numerical method.
The spinning speed of 3 km/min to 5 km/min was analyzed and the characteristic of PTT spinning process was compared with that
of poly(ethylene terephthalate) (PET). Velocity development of PTT was slower than that of PET. Although PTT’s spinning temperature
was lower than PET’s, the PTT solidified slower because of a smaller super-cooling and the large specific heat capacity. The
diameter profile of PTT decreases gradually in comparison with that of PET. PTT’s strain rate has a broader distribution than
PET’s and its maximum ranged from 541 to 570 s−1 for PET and 136 to 149 s−1 for PTT. PTT’s tensile stress was smaller than PET’s. 相似文献
403.
The dye-resist effect of reactive dye-resist agents in acid dyeing of silk was investigated. The dye-resist agent containing
dichlorotriazine achieved a higher resist effectiveness than others since they make a charge barrier against diffusion in
the silk fiber periphery due to the high reactivity of dichlorotriazine group. Especially, the increase in the number of ionic
groups in acid dyes leads to better electrostatic repulsion of reactive dye resist agent treated silk and thus improves the
resist effectiveness. However, the hydrophobicity effect of acid dyes on the dye-resist properties was relatively minor. 相似文献
404.
Injection molding is a flexible production method for manufacturing polymer products, but introduces residual stresses. This study employs the incremental hole-drilling method to measure the residual stresses in injection molded parts. To compare the results, the layer-removal method is utilized for measurement of residual stresses. A commercial software, Moldflow, is used for prediction of residual stresses in molded plastic parts. Results obtained by experiments and Moldflow analysis are compared. The incremental hole-drilling method is applicable to determination of the residual stresses in complex geometries and can be used as an adoptable technique for measurement of the residual stress in polymeric materials. 相似文献
405.
The alkaline dissolution behavior of sea-island type polyamide microfibers were successfully monitored using a cationic dye
staining method. Weight reduction behavior of the alkali-treated microfiber fabrics and the treated fabrics stained with cationic
dye were investigated in a comparative manner. The termination of dissolution monitored by both methods was also confirmed
by scanning electron microscopy. 相似文献
406.
Kang JH Song KH Woo JK Park MH Rhee MH Choi C Oh SH 《Plant foods for human nutrition (Dordrecht, Netherlands)》2011,66(3):298-305
Cancer prevention is effective and reduces health care costs because cancer is often a preventable disease that can be affected
by lifestyle factors. Therefore, researchers are interested in discovering natural compounds that have anticancer activities,
such as delaying the development of cancer and preventing its progression. One such natural agent is ginseng (Panax ginseng), which is traditionally used in some parts of the world as a popular remedy for various diseases including cancer. We hypothesized
that the ginsenoside Rp1, a component of ginseng, reduces cancer cell proliferation through inhibition of the insulin-like
growth factor 1 receptor (IGF-1R)/Akt pathway. We first tested the efficacy of Rp1 against human breast cancer cell lines.
Treatment with Rp1 inhibited breast cancer cell proliferation and inhibited both anchorage-dependent and -independent breast
cancer cell colony formation. In addition, treatment with 20 μM Rp1 induced cycle arrest and apoptosis-mediated cell growth
suppression. Our findings further indicated that Rp1 decreased the stability of the IGF-1R protein in breast cancer cells.
Therefore, we suggest that Rp1 has potential as an anticancer drug and that IGF-1R is an important target for treatment and
prevention of breast cancer. 相似文献
407.
Sung Hwoan Cho Sang-Mok Lee Byum Hee Park Sung Choon Ji Cheol Young Choi Jin Hwan Lee Yi Cheong Kim Jong Ha Lee Sung-Yong Oh 《Journal of the World Aquaculture Society》2007,38(1):68-73
A 10‐wk feeding trial to determine the effect of daily feeding ratio on growth and body composition of subadult olive flounder fed the extruded pellet (EP) was performed during the summer season. Thirteen flounder (an initial body weight of 319 g) per tank were distributed into fifteen 500‐L flow‐through tanks. Five treatments of feeding ratio in 5% decrement were prepared in triplicate: 100 (satiation), 95, 90, 85, and 80% of satiation. Fish in the control group (100% of satiation) were hand‐fed to apparent satiation twice a day. Then, feed allowance in the rest of the four groups was determined based on average feed consumption of fish in the control group. Weight gain of fish fed to 100% of satiation was significantly (P < 0.05) higher than that of fish fed to 85 and 80% of satiation but not significantly (P > 0.05) different from that of fish fed to 95 and 90% of satiation. Serum total protein, glucose, and glutamic pyruvic transaminase were not significantly (P > 0.05) affected by feeding ratio but triglyceride and glutamic oxaloacetic transaminase were. In considering these results, it can be concluded that optimum daily feeding ratio for growth of subadult olive flounder seemed to be 90% of satiation when fish were fed the EP twice a day during the summer season. 相似文献
408.
Tae-gi?Oh Kazumi?SakuramotoEmail author Seizo?Hasegawa Naoki?Suzuki 《Fisheries Science》2005,71(4):855-861
ABSTRACT: This paper investigates the relationship between sea-surface temperature (SST) and catch fluctuations in the Pacific stock of walleye pollock Theragra chalcogramma in Japan. Incorporating time lags between years of birth and harvest, the correlation coefficients between the catch and SST in two regions off the east coast of Hokkaido were calculated. The catch in year t had a high negative correlation with the SST during January–April and November–December of the years t- 2 and t- 3 in the spawning area. These results coincided well with the correlation observed in the northern 'Sea of Japan' stock. Both analyses suggested that the long-term catch fluctuations of the two stocks could be explained by the same mechanism, that is, the fluctuations would be explained by the SST in their spawning area during the spawning season using 2–3 or 3–5 years time lags, which corresponded to the dominant age of the catch within these two stocks. 相似文献
409.
In-Seok Park Eun-Mi Kim Seon Rang Woo Sung-Yong Oh Dong Soo Kim Jun Wook Hur 《Fisheries Science》2006,72(4):719-722
ABSTRACT: The aim of this study was to establish effective procedures for chromosome manipulation in greenling Hexagrammos otakii Jordan et Starks, which has enormous aquacultural potential. To accomplish this, temperature-dependent measurements of the mitotic intervals (τ0 ) were carried out. The τ0 in this fish was determined by averaging the duration of the first and third embryonic divisions at temperatures ranging 5–25°C. At higher temperatures, eggs developed faster and underwent more identical development. For greenling, τ0 were 341.1 ± 3.60 min at 5°C, 275.5 ± 4.53 min at 10°C, 189.7 ± 6.93 min at 15°C, 99.2 ± 8.27 min at 20°C and 34.2 ± 8.74 min at 25°C. There were strong, negative correlations between the τ0 and water temperatures at all temperatures studied ( Y = −79.3 X + 425.3, R 2 = 0.9968, where Y is the mitotic interval and X is the temperature). 相似文献
410.
A portable X-ray apparatus generates soft X-rays which have a continuous wavelength (wide range). When using continuous wavelength X-rays, the mass attenuation coefficient of the soft X-rays is changed as the penetrating depth in wood increases, unlike monochromatic X-rays which are usually used for medical purposes. In safety inspections of historic buildings, penetrating depth varies in an X-ray radiograph. Computerized tomography (CT) is a powerful tool that helps determine the density information of the inner sections of buildings. Because only portable X-rays can be used in historic buildings and the penetrating depth can vary, the mass attenuation coefficient of wood according to penetrating depth needs to be investigated. Therefore, in this study, we developed a statistical method which takes into account the influence of the penetrating depth on a density calculation made by a portable X-ray apparatus. X-ray tests were conducted on wood specimens of various depths. From the results, a statically determined mass attenuation coefficient (SMAC) ( $ \mu = - 0.214\ln (t) + 0.7251 $ ), which is the equation of mass attenuation coefficient according to the penetrating depth in wood, was derived to convert radiographs to density radiographs. All projections were converted into density profiles using two methods, average mass attenuation coefficient and SMAC. Based on the density profile for each projection, a density distribution of a cross-section was reconstructed by filtered back projection. Compared with the cases using a consistent mass attenuation coefficient, SMAC provided much higher precision in density prediction than the average mass attenuation coefficient. 相似文献