Perhaps you should try some spelling variations:
trinh doc » trinh hoa, trinh co, trinh hoi
trinh do » trinh ky
cu tren » tu tren, dua tren
thu san » thuy san, thu ban, phu san
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua
cam duc » cam xuc, cao duc, pham duc
tu san » tu ban, tu can, vu san
ma hoi » mai hoi, xa hoi, ma hoa
va cam » va cham, va cac, va cao

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

• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu san) OR (thu san)) ky nang ma hoi. hieu va cam duc va ((trinh do) OR (trinh doc)) cu tren~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu san) OR (thu san)) ky nang ma hoi. hieu va cam duc va ((trinh do) or (trinh doc)) cu tren~".
• Adding a wildcard symbol may retrieve word variants: ((tu san) OR (thu san)) ky nang ma hoi. hieu va cam duc va ((trinh do) or (trinh doc)) cu tren*.