Perhaps you should try some spelling variations:
david mant » david ma, david malone, david martin
form 7.2.1 » form 2.2.2
wang yang » wang yan, wang liang, wang yanling
yang yang » wang yan
yang zili » yang dali, yang li
david ian » david a, david n
form 2.1 » form 1.1, reform 2.1, form 3.2

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

• Performing a fuzzy search may retrieve terms with similar spellings: wang yang yang zili ((form 7.2.1) OR (form 2.1)) ((david mant) or (david ian)) hai ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: wang yang yang zili ((form 7.2.1) OR (form 2.1)) ((david mant) OR (david ian)) hai ;*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "wang yang yang zili ((form 7.2.1) OR (form 2.1)) ((david mant) or (david ian)) hai ;*".