Perhaps you should try some spelling variations:
nam thuoc » nam thuc, nam thu, nha thuoc
dau tieng » dau tien, cau tieng, day tieng
thu sach » thuat sach, thuoc sach, thu hoach
va hanh » van hanh, va thanh, ban hanh
va danh » va dinh, va dan, dia danh
tu sach » su sach, te sach, tu cach
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang
vi dau » vi dai, va dau, bi dau
va nam » van nam, ha nam, va nay

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) or (thu sach)) ty nang xa hoi. hieu va nam thuoc ((va danh) OR (va hanh)) vi dau tieng~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ty nang xa hoi. hieu va nam thuoc ((va danh) OR (va hanh)) vi dau tieng.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu sach)) ty nang xa hoi. hieu va nam thuoc ((va danh) OR (va hanh)) vi dau tieng".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) ty nang xa hoi. hieu va nam thuoc ((va danh) OR (va hanh)) vi dau tieng*.