Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
thu sach » tu sach, thuoc sach, thu hoach
cua viet » hoa viet, cua vat, cua dieu
tinh lap » trinh lap, tinh lao, dinh lap
hieu van » hieu va, thien van, lieu va
va tinh » may tinh
van cac » van hac, van cau, van bac
cac day » cac dan, cac dai, cac cay
hang xa » hoang xa, hang va, hang ca
ca viet » va viet, co viet, hoa viet
y hang » ly hang, ty hang, yu hang

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 (thuat sach)) y hang xa hoi. hieu van cac day va tinh lap ((cua viet) or (ca viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (thuat sach)) y hang xa hoi. hieu van cac day va tinh lap ((cua viet) OR (ca viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) OR (thuat sach)) y hang xa hoi. hieu van cac day va tinh lap ((cua viet) or (ca viet))".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) OR (thuat sach)) y hang xa hoi. hieu van cac day va tinh lap ((cua viet) or (ca viet))*.