Perhaps you should try some spelling variations:
luyen tap » tuyen tap
luyen thi » nguyen thi
thuc dung » thuoc dung, thuy dung, thuat dung
cac chat » cao chat, cac thuat, cac nha
tuc dung » tac dung, duc dung, thuoc dung
ban van » ban dan, ban va, tan van
van ty » van ky, van tu, van te

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

• If you are trying to use Boolean operators, they must be ALL CAPS: ((luyen tap) OR (luyen thi)) cac chat đe co ban van ty ((thuc dung) OR (tuc dung)) cong~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((luyen tap) OR (luyen thi)) cac chat đe co ban van ty ((thuc dung) or (tuc dung)) cong~".
• Adding a wildcard symbol may retrieve word variants: ((luyen tap) OR (luyen thi)) cac chat đe co ban van ty ((thuc dung) or (tuc dung)) cong*.