Perhaps you should try some spelling variations:
boost during » roosts during, books during, boom during
cost during » crust during, west during, roosts during
risk coping » risk pooling
wang wang » wang yang, wang liang, wang yong
risk cong » risk among, risk along, risk cost
yan jie » yang jie, yan jiu, yang jin

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: wang wang yan jie ((cost during) OR (boost during)) ((risk cong) OR (risk coping)) shu ;~.
• Adding a wildcard symbol may retrieve word variants: wang wang yan jie ((cost during) or (boost during)) ((risk cong) or (risk coping)) shu ;*.