医生通过氢呼气试验来诊断乳糖吸收不良与乳糖不耐受。正常情况下，人体呼气中仅含微量氢气。若存在乳糖吸收不良，未被消化吸收的乳糖经肠道菌群发酵，可产生氢气，最终导致呼气中氢气浓度显著升高。

LOS ANGELES, May 8 (Xinhua) -- A new study by researchers at the U.S. National Institutes of Health (NIH) has revealed a concerning rise in the incidence of several cancer types among individuals ...

SACRAMENTO, United States, May 3 (Xinhua) -- California lawmakers are racing to build its own National Institutes of Health (NIH) as the U.S. administration pushed deep federal funding cuts that ...