如何利用图书情报机构，提高文献检索的效率？请简述之。

[问答题]Look at the topic headings below, marked A, B, C, D E, and F, and match them with the paragraphs in the text below. There is one extra heading which you don’t need to use.　　Questions 1-5 are based on the following passage.　　A. Vanishing topsoil influences farm productivities　　B. Water is being polluted by chemical fertilisers　　C. Advantages and disadvantages of fuel produced from crop residues　　D. Environmental damages were even worsened by government policies　　E. A modest cut in subsidies is adopted in some countries　　F. Removal of certain subsidies achieves some positive results　　All these activities may have damaging environmental impacts. For example, land clearing for agriculture is the largest single cause of deforestation; chemical fertilizers and pesticides may contaminate water supplies; more intensive farming and the abandonment of fallow periods tend to exacerbate soil erosion; and the spread of monoculture and use of high-yielding varieties of crops have been accompanied by the disappearance of old varieties of food plants which might have provided some insurance against pests or diseases in future.　　　　Soil erosion threatens the productivity of land in both rich and poor countries. The United States, where the most careful measurements have been done, discovered in 1982 that about one-fifth of its farmland was losing topsoil at a rate likely to diminish the soil’s productivity. The country subsequently embarked upon a program to convert 11 percent of its cropped land to meadow or forest. Topsoil in India and China is vanishing much faster than in America.　　　　Government policies have frequently compounded the environmental damage that farming can cause. In the rich countries, subsidies for growing crops and price supports for farm output drive up the price of land. The annual value of these subsidies is immense: about $ 250 billion, or more than all World Bank lending in the 1980s. To increase the output of crops per acre, a farmer’s easiest option is to use more of the most readily available inputs: fertilisers and pesticides. Fertiliser use doubled in Denmark in the period 1960 - 1985 and increased in the Netherlands by 150 percent. The quantity of pesticides applied has risen too: by 69 percent in 1975 - 1984 in Denmark, for example, with a rise of 115 percent in the frequency of application in the three years from 1981.　　　　In the late 1980s and early 1990s some efforts were made to reduce farm subsidies. The most dramatic example was that of New Zealand, which scrapped most farm support in1984. A study of the environmental effects, conducted in 1993, found that the end of fertiliser subsidies had been followed by a fall in fertiliser use (a fall compounded by the decline in world commodity prices, which cut farm incomes). The removal of subsidies also stopped land-clearing and over-stocking, which in the past had been the principal causes of erosion. Farms began to diversify. The one kind of subsidy whose removal appeared to have been bad for the environment was the subsidy to manage soil erosion.　　　　In less enlightened countries, and in the European Union, the trend has been to reduce rather than eliminate subsidies, and to introduce new payments to encourage farmers to treat their land in environmentally friendlier ways, or to leave it fallow. It may sound strange but such payments need to be higher than the existing incentives for farmers to grow food crops. Farmers, however, dislike being paid to do nothing. In several countries they have become interested in the possibility of using fuel produced from crop residues either as a replacement for petrol (as ethanol) or as fuel for power stations (as biomass). Such fuels produce far less carbon dioxide than coal or oil, and absorb carbon dioxide as they grow.　　　　They are therefore less likely to contribute to the greenhouse effect. But they are rarely competitive with fossil fuels unless subsidized－ and growing them does no less environmental harm than other crops.

[多选题]Click the Exhibit button Which two statements are true if a NullPointerException is thrown on line 3 of class C？（）

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[多选题]财务一体化的现实意义叙述错误的是（）

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[单选题]进给率分为直线进给和旋转进给两种编程方式，下列各组中，（）是编程常采用的进给率。

[多选题]根据《工业固体废物采样制样技术规范》（HJ/T20—1998），工业固体废物采样人员应熟悉（）

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[问答题]如何利用图书情报机构，提高文献检索的效率？请简述之。

[问答题]如何利用图书情报机构，提高文献检索的效率？请简述之。

[问答题]图书情报机构网站检索有哪些？

[单选题]学科构成是信息资源结构最基本的要素。我国图书馆界认为，应以我国多数图书情报机构采用的为基础，参照国务院学位委员会公布的学科、专业目录和国外学科划分的一些标准，拟...

[单选题]学科构成是信息资源结构最基本的要素。我国图书馆界认为，应以我国多数图书情报机构采用的（）为基础，参照国务院学位委员会公布的学科、专业目录和国外学科划分的一些标准...

[问答题]独立的情报机构

[多选题]可以利用移动图书馆做什么（）。

[多选题]利用网络、图书馆的好处有（）。

[填空题]语言教育的内容要求，利用图书和绘画，引发幼儿对阅读和书写的兴趣，培养（）和（）技能。

[填空题]读者要提高阅读能力，一方面主要靠读者（），另一方面要发挥图书馆开发利用文献资源的作用及其指导阅读的作用。