Perhaps you should try some spelling variations:
manh hai » lanh hai, minh hai, thanh hai
danh hai » dang hai, lanh hai, danh hau
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
lam tuc » lam thuoc, lam truoc, luat tuc
van lam » van nam
nang ma » tang ma, sang ma, mang may
sach v » sach va, sach y, sach 2
tuc va » thuc va, truc va, tuc xa

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 v ((nang ma) or (nang cao)) hoi. hieu van lam tuc va ((danh hai) OR (manh hai)) cau thi~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach v ((nang ma) OR (nang cao)) hoi. hieu van lam tuc va ((danh hai) OR (manh hai)) cau thi.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach v ((nang ma) or (nang cao)) hoi. hieu van lam tuc va ((danh hai) OR (manh hai)) cau thi".
• Adding a wildcard symbol may retrieve word variants: su sach v ((nang ma) or (nang cao)) hoi. hieu van lam tuc va ((danh hai) OR (manh hai)) cau thi*.