hw检验呢?

If your sample size is large, this is OK.

样本将近1000，不知道是小容量还是大容量？如果ok，解释时应该怎么说呢？谢谢了。

Your sample size is not so small.
Generally speaking, as sample size increases, it's very hard to get "good values" for both Cox & Snell R 方  and Nagelkerke R 方. In your case, Nagelkerke R 方 is really not bad , if  the p value of Hosmer and Lemeshow Test>0.05, you have a good fit model.
Due to the above limitation, a lot of publications don't require Cox & Snell R 方  and Nagelkerke R 方 any more. But they do require "area under the ROC curve" for your model's descrimination power.

类似于线性回归的解释，能够解释方差总体的比重，不过还是应看HL检验