Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
thai cua » tai cuc, tri cua, dai cua
than cua » nhan cua, ban cua, gian cua
sach ky » sac ky, sach y, sach ty
van cac » van hac, van cau, dan cac
van bac » van ban, van bao, van hac
va danh » va dinh, va dan, va hanh
nang o » nang co, nang ho, nang ro
o hai » co hai, so hai, o lai

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ky nang o hai. thien ((van cac) OR (van bac)) nuoc va danh ((thai cua) or (than cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang o hai. thien ((van cac) OR (van bac)) nuoc va danh ((thai cua) OR (than cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang o hai. thien ((van cac) OR (van bac)) nuoc va danh ((thai cua) or (than cua)) tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang o hai. thien ((van cac) OR (van bac)) nuoc va danh ((thai cua) or (than cua)) tre*.