There are, indeed, alternative ideas to discount the claims of 500 people who witnessed Jesus alive and well (after his crucifixion). In chapter 10 of the book below, the author takes 80 pages to deal with them, so if you want a scholarly answer, you're just going to have to go and read a scholarly book.
One is called the Swoon Theory (that Christ never actually died on the cross, so that his body was not really dead - it just appeared to be dead.)
The Theft Theory is the one mentioned in the question, but it is seriously examined in the book.
Then there's the Hallucination Theory - all the people claiming to have seen Jesus alive after his crucifixion were imagining it - hallucinating even. ("What, all 500 of them?" I hear you cry.)
Another idea is that the women, then the others, went to the wrong tomb. That's seriously examined also.
The book dealing with objections to Christ's resurrection (and objections to many other Christian beliefs) is Evidence That Demands A Verdict, by Josh McDowell, Here's Life Publishing Inc. I have the 1979 edition. Much of it comes from notes for his lecture series, Christianity: Hoax or History? I recommend it.