Perhaps you should try some spelling variations:
va trien » va truyen, va thiet, va tuyen
duc manh » suc manh, duc anh, duc minh
nang mai » nang ma, nang tai, nang cai
lang mai » lang dai, lang hai, lang man
hoc can » hoc dan, hoc cao, hoc cac
hieu ve » hieu va, hieu van
te sac » te sach, te cac, te san
sac ky » cac ky, sai ky
ve cac » va cac, vien cac
vi va » vi van, vai va, vu va

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sac ky ((nang mai) or (lang mai)) khoi. hieu ve cac ((duc manh) or (hoc can)) hanh vi va trien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sac ky ((nang mai) OR (lang mai)) khoi. hieu ve cac ((duc manh) OR (hoc can)) hanh vi va trien.
• Adding a wildcard symbol may retrieve word variants: te sac ky ((nang mai) or (lang mai)) khoi. hieu ve cac ((duc manh) or (hoc can)) hanh vi va trien*.