Primary sources are evidence, artifacts or documents that originated from people who had direct contact with a situation. Secondary sources are those that discuss information from primary sources. A secondary source could be a point of view or analysis of an original historical event or document. For example, an immigration record would be a primary source, while a newspaper article about a family’s ancestry would be a secondary source. If the narrator of an account is not personally connected to the subject, they are more likely to remain objective. Web sources usually feature less strict controls than articles published in journals or books. Subjective sources that take opposing points of view can be extremely important, because they are able to give a larger view of the issue. Find “pain points” in your argument and document any possible ways to deal with them. It is easy to conduct research that supports your thesis. Try to find resources that disagree with your thesis so that you can handle objections to your project. Keep your sources separate until you determine you want the source to be part of your research. Although helpful in the research process, some resources will not be sufficiently valuable to support published research.

How would you rephrase that briefly using Chinese?
一级资源还是二级资源？实证、文物和来自直接目击者的文档是一级资源。 客观资源优于主观资源。 出版资料优于网上资源。 寻找对立资料。 使用前再次评估资源的可靠性。