????
???????????????????????????????????
| search for these words | ??????????????????????????????????????????????????????????????? |
| +search +for these words | ??????????"information"??????"for"????????????????? |
| +search -engine | ?????????????????????????? |
| "search engine" | ????????????????????? |
| user:Kim | ??????????????????????"user:"? |
| userid:6 | ??????????id???????????? |
| subject:assessment | ????????????????????????????"subject:"? |
?????????????????????? - ???????????????????????????