Perhaps you should try some spelling variations:
phan lap » phan dau
tu sach » thu sach, su sach, te sach
va phan » van phan, va phat, va phap
truc va » thuc va, thuc vat, trung va
hieu va » lieu va, hieu qua
sach ty » sach y, sach tu, sach thu
hieu su » hieu sau, tieu su, hieu so
tang ho » tang cho, tung ho, tang ha
nang ho » nang hoc, nang co, nang cao
su viet » so viet
lap su » lap du, lap tu, lai su

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ty ((nang ho) or (tang ho)) hoi. ((hieu su) or (hieu va)) cau truc va phan lap su viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty ((nang ho) OR (tang ho)) hoi. ((hieu su) OR (hieu va)) cau truc va phan lap su viet.
• Adding a wildcard symbol may retrieve word variants: tu sach ty ((nang ho) or (tang ho)) hoi. ((hieu su) or (hieu va)) cau truc va phan lap su viet*.