Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
kinh vai » kinh hai, kinh va, kinh van
hieu van » hieu va, thien van, lieu va
cau luc » cau truc, cau phuc
vai cuu » vai cua
va kinh » va tinh, qua kinh
cau duc » cao duc, chu duc, cau truc
cao hoi » cau hoi, co hoi, cao hoc
cuu tre » cua tre, cau tren, cau treo

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu sach) or (thu hoach)) ky nang cao hoi. hieu van ((cau duc) OR (cau luc)) va kinh vai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (thu hoach)) ky nang cao hoi. hieu van ((cau duc) OR (cau luc)) va kinh vai cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (thu hoach)) ky nang cao hoi. hieu van ((cau duc) OR (cau luc)) va kinh vai cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (thu hoach)) ky nang cao hoi. hieu van ((cau duc) OR (cau luc)) va kinh vai cuu tre*.