Perhaps you should try some spelling variations:
sloping land » mapping land
cost during » boost during, crust during, west during
during risk » using risk, during crises, during crisis
wang yang » wang yan, wang yanling
land cost » land costs, land code, end cost
how state » how estate, how states, how stable
how shih » how six, how she

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 liang) OR (wang yang)) sloping land cost during risk ((how shih) OR (how state)) ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((wang liang) OR (wang yang)) sloping land cost during risk ((how shih) or (how state)) ;~".
• Adding a wildcard symbol may retrieve word variants: ((wang liang) OR (wang yang)) sloping land cost during risk ((how shih) or (how state)) ;*.