河北乡
![河北乡](../cache/1337924.jpg)
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河北省38个乡儿童免疫接种率调查报告
Report on the coverage of immunization of children in 38 villages in
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于1984年生长季,利用氚水作为示踪剂对河北隆化碱房乡大水泉村西山28年生油松人工林树木蒸腾进行了测定。
Tritiated water was used as tracer to measure tree transpiration in a 28-year old Chinese pine plantation of north China during the growing season of 1984 . Transpiration rates of the pine tree varied obviously , the maximum value was found in July .