Perhaps you should try some spelling variations:
su sach » so sach, vu sach
truc va » thuc va, thuc vat, trung va
sach ly » sach y, sach lo, sach ty
hieu ve » hieu va, hieu van
sang ma » tang ma, sang tao, mang may
nang ma » tang ma, nang cao, mang may
luu tre » luu tru, cuu tre, luy tre
ve cac » va cac, vien cac
vi luu » vi lua

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ly ((nang ma) OR (sang ma)) hoi. hieu ve cac ((duc va) or (truc va)) hanh vi luu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ly ((nang ma) OR (sang ma)) hoi. hieu ve cac ((duc va) OR (truc va)) hanh vi luu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ly ((nang ma) OR (sang ma)) hoi. hieu ve cac ((duc va) or (truc va)) hanh vi luu tre".
• Adding a wildcard symbol may retrieve word variants: su sach ly ((nang ma) OR (sang ma)) hoi. hieu ve cac ((duc va) or (truc va)) hanh vi luu tre*.