I want to detect similar meaning in sentence "in my final year web based system"
The simple option is to implement it as a text search, preferably enriched with tf-idf weights and/or ignoring stop words: in theory all the possible topics (documents) are encoded as tf-idf vectors. When a query is provided it's also encoded as a tf-idf vector, then compared against all the documents vectors, typically with cosine similarity. The results are then ordered by the similarity score.

In practice various efficiency techniques can be used (the most obvious one is not to represent the vectors as sparse vectors).

There are obviously more advanced techniques, but it can get pretty complex so I would start with this simple option first and then consider improvements later.