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421.
Wang Y Cheng H Edwards RL He Y Kong X An Z Wu J Kelly MJ Dykoski CA Li X 《Science (New York, N.Y.)》2005,308(5723):854-857
A 5-year-resolution absolute-dated oxygen isotope record from Dongge Cave, southern China, provides a continuous history of the Asian monsoon over the past 9000 years. Although the record broadly follows summer insolation, it is punctuated by eight weak monsoon events lasting approximately 1 to 5 centuries. One correlates with the "8200-year" event, another with the collapse of the Chinese Neolithic culture, and most with North Atlantic ice-rafting events. Cross-correlation of the decadal- to centennial-scale monsoon record with the atmospheric carbon-14 record shows that some, but not all, of the monsoon variability at these frequencies results from changes in solar output. 相似文献
422.
423.
Judy E. Brown DVM MSc ; Alexa M.E. Bersenas DVM MSc DACVECC ; Karol A. Mathews DVM DVSc DACVECC Carolyn L. Kerr DVM PhD DVSc DACVA 《Journal of Veterinary Emergency and Critical Care》2009,19(5):416-425
Objective – The primary objective of this study was to assess the feasibility of noninvasive mechanical ventilation (NIV) in cats. The secondary objective was to determine whether cardiovascular parameters and anesthetic drug requirements associated with noninvasive ventilation differ from those associated with invasive ventilation. Design – Randomized, cross‐over design. Setting – A research laboratory in a veterinary teaching hospital. Animals – Eight healthy adult cats, 3 intact females and 5 intact males, weighing between 3 and 6 kg, were used. Interventions – Each cat was randomly assigned to NIV via nasal mask, or invasive ventilation using an endotracheal tube. Mechanical ventilation was performed for 6 hours. Anesthesia was provided using continuous infusions of propofol and butorphanol. After a minimum 9‐day washout period, the procedure was repeated using the alternate ventilation interface. Measurements and Main Results – Cardiovascular parameters (heart rate, rectal temperature, direct arterial blood pressure), arterial blood gases, drug requirements, sedation score, and ventilation parameters, were monitored throughout the procedures. These values were evaluated using ANCOVA for repeated measures. All cats were effectively ventilated using NIV. There were no significant differences in cardiovascular parameters, drug requirements, or sedation scores between groups. Although PaCO2 values did not differ, PaO2 values were significantly higher in the invasively ventilated group. Inspiratory tidal volumes were similar between groups, whereas expiratory tidal volumes were significantly lower in the NIV group. Inspiratory pressures were significantly higher in the NIV group. Respiratory frequency was significantly higher in the invasively ventilated group. Conclusions – NIV of cats is possible. However, currently it does not confer any cardiovascular benefit over invasive ventilation and drug requirements are similar. Use of a correctly fitted mask is essential for successful NIV as air leaks account for the observed discrepancy between inspiratory and expiratory volumes. Further investigation into this modality is warranted. 相似文献
424.
Forty grain samples, derived from six soft red winter wheat lines with 1BL/1RS and four genotypes without the translocation, grown in four diverse environments, were used to assess test weight, flour yield, protein content of grain and flour, rheological properties, and end-use characteristics in cakes and cookies. Wheat lines with 1BL/1RS had similar or higher mean test weights than lines without the translocation. Mean flour yields were similar for the two groups. Test weight was not predictive of flour yield. Mean values for grain moisture, grain protein, and rheological properties, as measured by farinograph for mixing time stability and mixing tolerance index, were similar for wheat lines with and without 1BL/1RS. In several cases, flour from lines with 1BL/1RS produced dough with greater mixing tolerance and cakes with higher volume and softer texture than did check lines without the translocation. However, the translocation in these soft red winter wheat lines resulted in higher farinograph water absorption by the flour and decreased cookie spread. The results of this study were novel in that end-use, specifically baking quality of soft wheat lines with 1BL/1RS, varied dramatically depending on whether cookies or cakes were evaluated. Therefore, use of single-product baking tests may lead to false conclusions regarding end-use quality of 1BL/1RS soft wheat. Direct comparison between a pair of sister lines with and without 1BL/1RS indicated that the translocation had adverse effects on quality as exemplified by lower flour yield, greater farinograph water absorption, and reduced cookie diameter. However, the 1BL/1RS line had greater mixing tolerance and similar cake volume and texture scores in comparison to its sister line. In summary, 1BL/1RS lines were identified in which quality characteristics exceeded those of control cultivars and commercial flours. Genetic background and environmental factors probably affected milling and baking quality to a greater extent than the translocation. Many of the negative quality attributes previously associated with 1BL/1RS are probably due to genetic background effects and, therefore, could be greatly diminished with improvement of the genetic background in which the translocation resides. 相似文献