How to Add Business Logic to the Domain Service in Domain-Driven-Design?

in my project ,the Business Logic all in the Application Service,Domain Service just some entity,who can tell me or give me a example to show How to Add Business Logic to the Domain Service in Domain-Driven-Design? very thanks!

UPDATE

i write a simple solutation,this solutation is a vote system,the solutation main part is:

Vote.Application.Service.VoteService.cs:

namespace Vote.Application.Service
{
    public class VoteService
    {
        private IVoteRepository _voteRepository;
        private IArticleRepository _articleRepository;

        public VoteService(IVoteRepository voteRepository,IArticleRepository articleRepository)
        {
            _voteRepository = voteRepository;
            _articleRepository = articleRepository;
        }

        public bool AddVote(int articleId, string ip)
        {
            var article = _articleRepository.Single(articleId);
            if (article == null)
            {
                throw new Exception("this article not exist!");
            }
            else
            {
                article.VoteCount++;
            }

            if (IsRepeat(ip, articleId))
                return false;

            if (IsOvertakeTodayVoteCountLimit(ip))
                return false;

            _voteRepository.Add(new VoteRecord()
            {
                ArticleID = articleId,
                IP = ip,
                VoteTime = DateTime.Now
            });

            try
            {
                _voteRepository.UnitOfWork.Commit();
                return true;
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }

        private bool IsRepeat(string ip, int articleId)
        {
            //An IP per article up to cast 1 votes
            //todo
            return false;
        }

        private bool IsOvertakeTodayVoteCountLimit(string ip)
        {
            //An IP per day up to cast 10 votes
            //todo
            return false;
        }
    }
}

Vote.Domain.Contract.IVoteRepository.cs:

namespace Vote.Domain.Contract
{
    public interface IVoteRepository
        : IRepository<VoteRecord>
    {
        void Add(VoteRecord model);
    }
}

Vote.Domain.Contract.IArticleRepository.cs:

namespace Vote.Domain.Contract
{
    public interface IArticleRepository
        : IRepository<Article>
    {
        void Add(VoteRecord model);

        Article Single(int articleId);
    }
}

Vote.Domain.Entities.VoteRecord:

namespace Vote.Domain.Entities
{
    public class VoteRecord
    {
        public int ID { get; set; }

        public DateTime VoteTime { get; set; }

        public int ArticleID { get; set; }

        public string IP { get; set; }
    }
}

Vote.Domain.Entities.Article:

namespace Vote.Domain.Entities
{
    public class Article
    {
        public int ID { get; set; }

        public string Title { get; set; }

        public string Content { get; set; }

        public int VoteCount { get; set; }
    }
}

i want move the Business Login in application.service to Domain.service(current not this project),who can help me?how to do is reasonable? very thanks!