Perhaps you should try some spelling variations:
dau tren » dau tien, dat tren, dau tieng
nang van » dang van, tang van, lang van
hieu van » thien van, lieu va, hieu ve
va danh » va dan, va hanh, dia danh
va dinh » van dinh, va kinh, va tinh
te sach » toc sach
van hoe » van hoa, van hoc, van hieu
hieu va » lieu va, hieu qua
y nang » ky nang, ly nang, v nang
va dau » va dao

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach y nang van hoe. ((hieu van) OR (hieu va)) nang luc ((va danh) or (va dinh)) va dau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach y nang van hoe. ((hieu van) OR (hieu va)) nang luc ((va danh) OR (va dinh)) va dau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach y nang van hoe. ((hieu van) OR (hieu va)) nang luc ((va danh) or (va dinh)) va dau tren".
• Adding a wildcard symbol may retrieve word variants: te sach y nang van hoe. ((hieu van) OR (hieu va)) nang luc ((va danh) or (va dinh)) va dau tren*.