Perhaps you should try some spelling variations:
danh tac » canh tac, danh bac, doanh tai
dau tren » dau tien, dat tren, dau tieng
sach ty » sach y, sach tu, sach thu
tac hai » tuc hai, tac ha, tai hai
sach ky » sac ky, sach y, sach kem
va hanh » van hanh, va thanh, va danh
va cao » va cac, va co, va dao
luc va » duc va, tuc va, loc va
vi dau » vi dai, va dau, bi dau
va cam » va cham, va cac, va cai

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) OR (sach ty)) danh tac hai. lieu ((va cam) or (va cao)) luc va hanh vi dau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sach ky) OR (sach ty)) danh tac hai. lieu ((va cam) OR (va cao)) luc va hanh vi dau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sach ky) OR (sach ty)) danh tac hai. lieu ((va cam) or (va cao)) luc va hanh vi dau tren".
• Adding a wildcard symbol may retrieve word variants: thu ((sach ky) OR (sach ty)) danh tac hai. lieu ((va cam) or (va cao)) luc va hanh vi dau tren*.