Perhaps you should try some spelling variations:
viet cac » viet ca, viet bac, viet cau
vien cac » vien bach, vien dai, vien da
thu sach » thuat sach, thuoc sach, thu hoach
hanh dao » lanh dao, thanh dat, thanh dam
dao cua » dai cua, day cua, dan cua
va hanh » van hanh, va thanh, va danh
tu sach » su sach, te sach, tu cach
nang xa » nang x, lang xa, nang ma
ly nang » ky nang, ly hang, ly vang
luc va » duc va, tuc va, loc va
cua te » cua tu

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)) ly nang xa hoi. sieu ((viet cac) OR (vien cac)) luc va hanh dao cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ly nang xa hoi. sieu ((viet cac) OR (vien cac)) luc va hanh dao cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu sach)) ly nang xa hoi. sieu ((viet cac) OR (vien cac)) luc va hanh dao cua te".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) ly nang xa hoi. sieu ((viet cac) OR (vien cac)) luc va hanh dao cua te*.