Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
cau theo » cau thi, cau tao
lang xa » dang xay, lang van
lang ha » long ha
sach ky » sac ky, sach y, sach ty
dan tai » van tai, dan thi, han tai
tai cau » tai cac, tai cao
hieu va » hieu qua
thu va » thuc va, thue va, tu va
va dan » ca dan, va dao, va dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ky ((lang xa) OR (lang ha)) hoi. ((hieu va) OR (lieu va)) nam thu va dan tai cau theo~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky ((lang xa) OR (lang ha)) hoi. ((hieu va) OR (lieu va)) nam thu va dan tai cau theo".
• Adding a wildcard symbol may retrieve word variants: toc sach ky ((lang xa) OR (lang ha)) hoi. ((hieu va) OR (lieu va)) nam thu va dan tai cau theo*.