Perhaps you should try some spelling variations:
dang cau » hang cau, bang cau, dang mau
hieu van » hieu va, thien van, lieu va
nam thuc » nam thuoc, am thuc, nam thu
tinh tai » trinh tai, tinh thai, tinh hai
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
ky dang » ky nang, ky danh
cam tuc » cam xuc, cam tu, dam thuc
va tinh » may tinh
buu tre » cuu tre

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 dang cau hoi. hieu van ((cam tuc) or (nam thuc)) va tinh tai buu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky dang cau hoi. hieu van ((cam tuc) OR (nam thuc)) va tinh tai buu tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky dang cau hoi. hieu van ((cam tuc) or (nam thuc)) va tinh tai buu tre*.