Perhaps you should try some spelling variations:
trinh nghien » trinh nghe, kinh nghiem, trinh thiet
trach nhiem » trac nghiem
sach doanh » sach danh, sach tranh, cac doanh
nghiep du » nghiep dau, nghiep vu, nghiep tu
thu sach » tu sach, thuat sach, thuoc sach
va hoc » van hoc
du hoc » tu hoc, duoc hoc

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 ((trach nhiem) or (trinh nghien)) va hoc ) or ( thu sach doanh nghiep du hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( thu sach ((trach nhiem) OR (trinh nghien)) va hoc ) OR ( thu sach doanh nghiep du hoc )).
• Adding a wildcard symbol may retrieve word variants: (( thu sach ((trach nhiem) or (trinh nghien)) va hoc ) or ( thu sach doanh nghiep du hoc ))*.