1. A method that uses a processor to determine a document rank, comprising: calculating, using the processor, a document rank score of a second document based on a first term relationship score of a first document and a first contribution score, the first contribution score being determined based on a common keyword between the first document and the second document; changing the first term relationship score to a second term relationship score; and updating the document rank score of the second document based on the second term relationship score, wherein the first document is linked by a link to the second document, wherein the first term relationship score is determined based on content of the first document and the link, and wherein updating the document rank score comprises determining whether each of a plurality of contribution scores is greater than a predetermined threshold value, whereby if one of the contribution scores is less than or equal to the predetermined threshold value, that contribution score is set to a zero value.
1. A method that uses a processor to determine a document rank, comprising: calculating, using the processor, a document rank score of a second document based on a first term relationship score of a first document and a first contribution score, the first contribution score being determined based on a common keyword between the first document and the second document; changing the first term relationship score to a second term relationship score; and updating the document rank score of the second document based on the second term relationship score, wherein the first document is linked by a link to the second document, wherein the first term relationship score is determined based on content of the first document and the link, and wherein updating the document rank score comprises determining whether each of a plurality of contribution scores is greater than a predetermined threshold value, whereby if one of the contribution scores is less than or equal to the predetermined threshold value, that contribution score is set to a zero value. 2. The method of claim 1 , wherein calculating the document rank score of the second document comprises calculating a first contribution score based on a first contribution coefficient with respect to the common keyword and the first term relationship score; and wherein updating the document rank score of the second document further comprises: calculating a second contribution coefficient with respect to the common keyword; calculating a second contribution score based on the first contribution coefficient, the first term relationship score, the second contribution coefficient, and the second term relationship score; and determining the document rank score of the second document according to the second contribution score.