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61.
Utilization of polar metabolite profiling in the comparison of juvenile wood and compression wood in loblolly pine (Pinus taeda) 总被引:1,自引:0,他引:1
Juvenile wood (JW) of conifers is often associated with compression wood (CW), with which it is sometimes believed to be identical. To determine whether JW and CW can be distinguished metabolically, we compared gas chromatographic profiles of 25 polar metabolites from rooted cuttings of a single loblolly pine (Pinus taeda L.) clone raised in controlled environment chambers and subject to three treatments: (1) grown erect with minimal wind sway (control); (2) swayed by wind from oscillating fans; and (3) with 30-cm growth increments successively bent at an angle of 45 degrees to the vertical. Profiles were compared by principal component analysis. Substantial increases in abundances of coniferin and p-glucocoumaryl alcohol separated immature JW-forming xylem tissues of the control trees from the CW-forming xylem of the bent and swayed trees. 相似文献
62.
Suzuki N Suzuki S Millar DG Unno M Hara H Calzascia T Yamasaki S Yokosuka T Chen NJ Elford AR Suzuki J Takeuchi A Mirtsos C Bouchard D Ohashi PS Yeh WC Saito T 《Science (New York, N.Y.)》2006,311(5769):1927-1932
IRAK-4 is a protein kinase that is pivotal in mediating signals for innate immune responses. Here, we report that IRAK-4 signaling is also essential for eliciting adaptive immune responses. Thus, in the absence of IRAK-4, in vivo T cell responses were significantly impaired. Upon T cell receptor stimulation, IRAK-4 is recruited to T cell lipid rafts, where it induces downstream signals, including protein kinase C activation through the association with Zap70. This signaling pathway was found to be required for optimal activation of nuclear factor kappaB. Our findings suggest that T cells use this critical regulator of innate immunity for the development of acquired immunity, suggesting that IRAK-4 may be involved in direct signal cross talk between the two systems. 相似文献
63.
Dong M Yeh F Tepp WH Dean C Johnson EA Janz R Chapman ER 《Science (New York, N.Y.)》2006,312(5773):592-596
How the widely used botulinum neurotoxin A (BoNT/A) recognizes and enters neurons is poorly understood. We found that BoNT/A enters neurons by binding to the synaptic vesicle protein SV2 (isoforms A, B, and C). Fragments of SV2 that harbor the toxin interaction domain inhibited BoNT/A from binding to neurons. BoNT/A binding to SV2A and SV2B knockout hippocampal neurons was abolished and was restored by expressing SV2A, SV2B, or SV2C. Reduction of SV2 expression in PC12 and Neuro-2a cells also inhibited entry of BoNT/A, which could be restored by expressing SV2 isoforms. Finally, mice that lacked an SV2 isoform (SV2B) displayed reduced sensitivity to BoNT/A. Thus, SV2 acts as the protein receptor for BoNT/A. 相似文献
64.
The structural performance of finger-jointed laminated bamboo was investigated for two bamboo species by considering the finger
length, profile orientation, lamination direction, culm growth height, and mechanical properties of bamboo materials. Based
on the growth height variation and bamboo species, the best finger-jointed laminated bamboo was found for the lamina processed
from the middle growth height of a moso bamboo culm with the finger profile shown on the width face of the beam. It was 38.7%
higher in bending strength than the lowest group, with the lamina from the lower ma bamboo culm showing the finger profile
on the thickness face of the beam. When considering the finger length and lamination orientation, the strongest finger-jointed
laminated bamboo joined with an 18-mm finger, showing the finger profile on the width face of a vertically laminated beam
was 50.1% higher in bending strength than the lowest group having a 12-mm finger showing the finger profile on the thickness
face of a vertically laminated beam. The laminated ma bamboo showed higher finger-joint efficiency, 11.6%, than moso bamboo,
and the members showing the finger profile on the width surface was 12.3% better in joint efficiency than that showing on
the thickness surface of the beam. 相似文献
65.
Axonal voltage-gated potassium (Kv1) channels regulate action-potential invasion and hence transmitter release. Although evolutionarily conserved, what mediates their axonal targeting is not known. We found that Kv1 axonal targeting required its T1 tetramerization domain. When fused to unpolarized CD4 or dendritic transferrin receptor, T1 promoted their axonal surface expression. Moreover, T1 mutations eliminating Kvbeta association compromised axonal targeting, but not surface expression, of CD4-T1 fusion proteins. Thus, proper association of Kvbeta with the Kv1 T1 domain is essential for axonal targeting. 相似文献
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69.
Rice flour (37% moisture content) was used to examine the effects of feed rate and screw speed on the specific energy input during single-screw extrusion cooking. Torque, raised by decreasing screw speed or increasing feed rate, was found to be a power law function of the ratio of feed rate to screw speed (Fr/Ss) with r2 > 0.94. Specific mechanical energy (SME) calculated from torque also was a power law function of Fr/Ss with r2 >0.84 and negative power law indices. The SME obtained was in the 225–481 kJ/kg range. Thus the extruder can be considered low shear. Increasing SME raised the die temperature and decreased both intrinsic viscosity and water absorption index (WAI). The degree of gelatinization and intrinsic viscosity of extrudates also were power law functions of Fr/Ss. The intrinsic viscosity correlated well with the degree of gelatinization, WAI, and cooking loss, and appeared to be a good index of the extrudate properties. Different screw profiles also affect torque measurement. 相似文献
70.