Perhaps you should try some spelling variations:
cau tren » cu tren, ca tren, cau treo
dau tren » dau tien, dat tren, dau tieng
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
cao hoi » cau hoi, co hoi, cao hoc
hieu ve » hieu va, hieu van
truc va » thuc va, thuc vat, trung va
ve cam » ve cham, ve cac, va cam
tuc va » thuc va, tuc xa, duc va

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 nang cao hoi. hieu ve cam ((tuc va) or (truc va)) dan ca ((cau tren) OR (dau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang cao hoi. hieu ve cam ((tuc va) OR (truc va)) dan ca ((cau tren) OR (dau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang cao hoi. hieu ve cam ((tuc va) or (truc va)) dan ca ((cau tren) OR (dau tren))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang cao hoi. hieu ve cam ((tuc va) or (truc va)) dan ca ((cau tren) OR (dau tren))*.