Perhaps you should try some spelling variations:
dieu cua » dieu tra
dien cua » dien cuc, dien cu, tien cua
tu sach » thu sach, su sach, te sach
truc va » thuc va, thuc vat, trung va
va danh » va dinh, va dan, va hanh
hieu va » hieu qua
sach ky » sac ky, sach y, sach ty
lang ha » long ha
ky lang » ky nang, ky dang, ky tang
ha hoi » hoa hoi, ha noi, xa hoi

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 ky lang ha hoi. ((lieu va) or (hieu va)) cau truc va danh ((dien cua) OR (dieu cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky lang ha hoi. ((lieu va) OR (hieu va)) cau truc va danh ((dien cua) OR (dieu cua)) tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky lang ha hoi. ((lieu va) or (hieu va)) cau truc va danh ((dien cua) OR (dieu cua)) tre*".