Perhaps you should try some spelling variations:
sach thi » sach thu, sach tai, sach thieu
thi nang » thi cong, ki nang, thi hanh
van hanh » van thanh, ban hanh, van anh
xuc van » duc van, luc van, vuc van
vu sach » vu bach, su sach, vu khach
ve cam » ve cham, ve cac, ve cai
va cam » va cham, va cac, va cao
nang o » nang co, nang ho, nang ro
o hai » co hai, so hai, o lai
vi va » vai va, vu va, bi va

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach thi nang o hai. hieu ((ve cam) or (va cam)) xuc van hanh ((vi va) OR (vi van)) viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach thi nang o hai. hieu ((ve cam) OR (va cam)) xuc van hanh ((vi va) OR (vi van)) viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach thi nang o hai. hieu ((ve cam) or (va cam)) xuc van hanh ((vi va) OR (vi van)) viet".
• Adding a wildcard symbol may retrieve word variants: vu sach thi nang o hai. hieu ((ve cam) or (va cam)) xuc van hanh ((vi va) OR (vi van)) viet*.