Perhaps you should try some spelling variations:
thi nang » thi cong, ki nang, thi hanh
sach thi » sach thu, sach tai, sach thieu
vu sach » vu bach, su sach, vu khach
va chat » van chat, va phat, cao chat
duc van » duc va, duc tan, duc manh
vuc van » luc van, thuc van, chuc van
ca viet » va viet, co viet, hoa viet
ve cam » ve cham, ve cac, va cam
nang o » nang co, nang ho, nang ro
o hai » co hai, so hai, o lai
vi ca » vit ca, li ca, va ca

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 chat)) ((vuc van) OR (duc van)) hanh vi ca 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 chat)) ((vuc van) OR (duc van)) hanh vi ca 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 chat)) ((vuc van) OR (duc van)) hanh vi ca viet".
• Adding a wildcard symbol may retrieve word variants: vu sach thi nang o hai. hieu ((ve cam) or (va chat)) ((vuc van) OR (duc van)) hanh vi ca viet*.