全文获取类型
收费全文 | 34篇 |
免费 | 4篇 |
国内免费 | 2篇 |
专业分类
测绘学 | 1篇 |
大气科学 | 1篇 |
地球物理 | 12篇 |
地质学 | 16篇 |
海洋学 | 6篇 |
天文学 | 2篇 |
综合类 | 1篇 |
自然地理 | 1篇 |
出版年
2020年 | 1篇 |
2019年 | 1篇 |
2017年 | 1篇 |
2016年 | 2篇 |
2012年 | 2篇 |
2011年 | 1篇 |
2010年 | 1篇 |
2008年 | 3篇 |
2007年 | 2篇 |
2006年 | 3篇 |
2005年 | 1篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 1篇 |
2001年 | 3篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 4篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1984年 | 1篇 |
排序方式: 共有40条查询结果,搜索用时 765 毫秒
11.
13.
14.
Kim IC Chang SY Williams TD Ja Kim Y Yoon YD Lee YS Park EH Lee JS 《Marine environmental research》2004,58(2-5):687-691
We cloned the vitellogenin gene from the self-fertilizing fish Rivulus marmoratus, and sequenced 12,326 bp. The number of exons of R. marmoratus and rainbow trout vitellogenin genes were different, and also the splicing junctions are different throughout most of the exons and introns but the amino acid similarity of R. marmoratus vitellogenin gene to other species was rather high. In promoter region of R. marmoratus vitellogenin gene, there were several E2 binding sites and the estrogen response element (ERE). We discuss here the gene structure and expression of R. marmoratus vitellogenin gene. 相似文献
15.
Boswell TD 《The Journal of geography》1984,83(2):65-72
A new approach to solving some of the problems that information, education, and communication (IEC) programs have been facing is proposed. The approach is based on the use of the "Appropriate Practical and Technical Information Section Cube" (APTISC). The APTISC model can systematically identify 64 different types of IEC programs. The approach logically arises from the following principles of effective IEC and should therefore be acceptable: problem-oriented, people-oriented, practical oriented, and professional-or technical-oriented. To start developing the IEC program systematically, one begins by asking the following simple questions: what is the problem; who are the people responsible for these problems; and what type of professional or technical knowledge is needed to solve the lack of knowledge, attitude, practice, or IEC capabilities (KAPI). The problem may be lack of knowledge (K), attitude (A), practice (P), of IEC capabilities (I) or any combination of them. A lack of KAPI can arise from various groups of people, and these groups must be identified. The type of professional or technical knowledge needed to solve the lack of KAPI can be divided into 4 types, i.e., technical information, technical application, technical practice, and technical supervision. For the purpose of actually developing the program the identified cube can be broken down into 4 main components: M1 = man (who is the comminicator); M2 = message (to be received by the audience); M3 = method (to transmit the message); and M4 = media (to convey the message). Each of these components has to be identified before the program can be initiated. Other supporting components can also be considered, e.g., management, material, morale, and money. These should be analyzed in relation to IEC programs being developed. It is worth considering the application of the APTISC Approach in developing IEC programs. This approach will help maximize the effectiveness of available resources by concentrating them on the areas of greastest need. 相似文献
16.
17.
在荆山群建组剖面实地研究的基础上,补测了野头组的禄格庄剖面,考察了荆山区至平度区荆山群的相变规律,采用数学地质方法研究荆山群地层结构及生成环境,得知:荆山群无论在原岩建造、岩性组合、生成的古地理环境均不同于胶东岩群。荆山群形成于不稳定的冒地槽环境,相变剧烈,由荆山区至平度区厚度锐减,火山活动减弱。荆山群在总体上表现为三大周期,对应三个组,各组内部具有不同的沉积韵律和拟周期,野头组火山沉积和禄格庄组的砂泥质沉积是荆山群金的高丰度部位。野头组的火山建造形成于海底裂陷环境,金主要赋存在正常沉积与火山沉积的交变带中。产于进入火山活动和由火山活动转出的历史阶段,属火山喷气—溢流阶段的产物。 相似文献
18.
19.
裂隙率作为表征岩体裂隙特征的一项重要参数,有线裂隙率、面裂隙率、体裂隙率3种表征方法。目前常用测线法、统计窗法获取线、面裂隙率仅能从一维或二维反映裂隙发育情况,其方法还存在测量结果随机性、应用受出露条件所限等不足;现有体裂隙率测量方法也存在着实际应用性较差、成本高等问题,尚缺乏简便易操作的野外测量方法。为此本文提出了一种新的野外测量岩体体裂隙率的工作方法--球体法。由于构造、成岩裂隙发育的组系性、方向性,球体法根据各组裂隙产状从不同方向进行观测,通过多次测量统计岩体出露面上裂隙的发育特征,推断岩体内部裂隙的发育状况,其值能更好地反映局部区域岩体内部裂隙发育程度。此外,在测量时利用专利仪器可以得到沿裂隙面法线方向上隙宽以及隙间距数据真实值,测量条件对出露面平整情况要求不高,测量结果受露头平整性影响不大,具有更好的实用性。本文以安庆大龙山采石场研究区为例应用球体法,野外现场测量表明该方法可以在较为方便操作的基础上实现快速测量;研究区体裂隙率均值为2. 286%,集中分布在1%~4%,结合研究区实际情况以及误差分析结果,球体法可以很好地反映研究区各个测量点的裂隙发育程度。 相似文献
20.