Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
toan cua » than cua, tan cua, doanh cua
thuc tap » tuc tap, thuc thai, thuc vat
tuc thai » thuc thai, toc thai, tuc hai
hieu van » hieu va, thien van, lieu va
doc sach » hoc sach, nuoc sach, dac sac
dang xa » dang xay, lang xa, dang ha
ky dang » ky nang, ky danh
cua te » cua tu

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) OR (doc sach)) ky dang xa hoi. hieu van nam ((tuc thai) or (thuc tap)) tinh toan cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) ky dang xa hoi. hieu van nam ((tuc thai) OR (thuc tap)) tinh toan cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) OR (doc sach)) ky dang xa hoi. hieu van nam ((tuc thai) or (thuc tap)) tinh toan cua te".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) OR (doc sach)) ky dang xa hoi. hieu van nam ((tuc thai) or (thuc tap)) tinh toan cua te*.