Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
vai cua » dai cua, hai cua, lai cua
dau vai » dau va, dau hai, dau tai
cua tre » cua te, cuu tre, cua triet
ky dang » ky nang, ky danh
ky lang » ky nang, ky tang, tay lang
ve cam » ve cham, ve cac, ve cai
va cam » va cham, va cac, va cao
tuc va » thuc va, truc va, tuc xa
va dau » va dao

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