Perhaps you should try some spelling variations:
during crisis » during crises, housing crisis
code during » care during, code using, role during
huang jing » huang ting, huang ying, wang jing
wang liang » wang yang
land code » land cover
how slum » how sub, how sun
how slow » how low, how slower, grow slow

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 ((huang jing) OR (wang liang)) land code during crisis ((how slum) OR (how slow)) ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "wang ((huang jing) or (wang liang)) land code during crisis ((how slum) OR (how slow)) ;~".
• Adding a wildcard symbol may retrieve word variants: wang ((huang jing) or (wang liang)) land code during crisis ((how slum) OR (how slow)) ;*.