Perhaps you should try some spelling variations:
dam planning » term planning, from planning, land planning
planning can » planning chain, planning case, planning land
china tan » china top, china two, china taiwan
sang minh » kang minah, anh minh, song min
congo can » congo call, cong van, congo a
tan sang » tan yang, tang tang, tan hong
cong tan » hong tan, cong van, cong sun

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: dam planning can china tan sang minh ((cong tan) OR (congo can)) ;~.
• Adding a wildcard symbol may retrieve word variants: dam planning can china tan sang minh ((cong tan) or (congo can)) ;*.