Perhaps you should try some spelling variations:
sang thao » sang tao, sang than, rang thao
thao khoa » thai khoa, toan khoa, pham khoa
dieu cua » dieu tra
te sach » toc sach
truc va » thuc va, thuc vat, trung va
va danh » va dinh, va dan, va hanh
vai cua » dai cua, hai cua, lai cua
hieu va » lieu va, hieu qua
sach ky » sac ky, sach y, sach ty
hieu ve » hieu van
ky sang » ky nang, ky dang, ky tang

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 ky sang thao khoa. ((hieu ve) or (hieu va)) cau truc va danh ((dieu cua) or (vai cua)) vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky sang thao khoa. ((hieu ve) OR (hieu va)) cau truc va danh ((dieu cua) OR (vai cua)) vat.
• Adding a wildcard symbol may retrieve word variants: te sach ky sang thao khoa. ((hieu ve) or (hieu va)) cau truc va danh ((dieu cua) or (vai cua)) vat*.