全文获取类型
收费全文 | 90104篇 |
免费 | 1296篇 |
国内免费 | 1487篇 |
专业分类
安全科学 | 3793篇 |
废物处理 | 3290篇 |
环保管理 | 13759篇 |
综合类 | 21792篇 |
基础理论 | 26288篇 |
环境理论 | 72篇 |
污染及防治 | 14382篇 |
评价与监测 | 5375篇 |
社会与环境 | 3585篇 |
灾害及防治 | 551篇 |
出版年
2022年 | 887篇 |
2021年 | 874篇 |
2020年 | 697篇 |
2019年 | 893篇 |
2018年 | 1165篇 |
2017年 | 1208篇 |
2016年 | 2203篇 |
2015年 | 1911篇 |
2014年 | 2679篇 |
2013年 | 9368篇 |
2012年 | 2227篇 |
2011年 | 2411篇 |
2010年 | 3320篇 |
2009年 | 3401篇 |
2008年 | 1902篇 |
2007年 | 1693篇 |
2006年 | 2201篇 |
2005年 | 2202篇 |
2004年 | 2499篇 |
2003年 | 2352篇 |
2002年 | 1894篇 |
2001年 | 2235篇 |
2000年 | 1958篇 |
1999年 | 1542篇 |
1998年 | 1390篇 |
1997年 | 1378篇 |
1996年 | 1488篇 |
1995年 | 1579篇 |
1994年 | 1484篇 |
1993年 | 1325篇 |
1992年 | 1318篇 |
1991年 | 1283篇 |
1990年 | 1235篇 |
1989年 | 1198篇 |
1988年 | 1047篇 |
1987年 | 968篇 |
1986年 | 995篇 |
1985年 | 1064篇 |
1984年 | 1153篇 |
1983年 | 1163篇 |
1982年 | 1171篇 |
1981年 | 1088篇 |
1980年 | 941篇 |
1979年 | 918篇 |
1978年 | 816篇 |
1977年 | 707篇 |
1976年 | 636篇 |
1975年 | 599篇 |
1973年 | 625篇 |
1972年 | 621篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
161.
162.
163.
164.
M. Blunck W. -D. Busse G. Meister E. Möller A. Mullen L. A. A. van Rooijen 《Die Naturwissenschaften》1989,76(3):96-98
Online searching in publically available patent files opens up interesting possibilities to provide a rapid response to critical questions. A computerized analysis of all patents of leading German pharmaceutical companies over the last decade in important indication areas is described. Supported by subsequent manual processing of individual patents it is shown that duplicate experiments on animals practically never occur. 相似文献
165.
166.
167.
The Australian buprestid beetle Merimna atrata (Coleoptera: Buprestidae) approaches forest fires because its larvae develop in freshly burnt wood. So far nothing is known
about possible sensory systems enabling the beetles to detect fires and to cope with the thermal environment close to the
flames. We found that M. atrata has two pairs of infrared (IR) organs on the ventrolateral sides of the abdomen. Each IR organ consists of a specialized
IR-absorbing area which is innervated by one thermosensitive multipolar neuron. The primary dendritic branches ramify into
more than 800 closely packed terminal endings which contain a large number of mitochondria. We called the special morphology
of the dendritic region a terminal dendritic mass. The type of IR receptor found in M. atrata is unique in insects and can best be compared with the IR organs of boid snakes.
Received: 14 August 2000 / Accepted in revised form: 18 October 2000 相似文献
168.
Laperdina T. G. Melnikova M. V. Koval A. T. Sidorov Y. F. Nagorny V. A. Ostapchuk V. I. 《环境科学学报(英文版)》2000,(Z1)
IntroductionSiberiaandtheFarEastaretheoldestandtherichestgold miningareasofRussia .Intensivegold miningherestartedinthebeginningofthe 19thcentury(Vyazelshchikov ,1963) .Forthemostpartgold bearingoresandsandswereprocessedwiththeuseofamalgamationmethodforgolde… 相似文献
169.
170.
The abundance patterns of ant communities were monitored with pitfall traps during 14 weeks in four northern California, dry farmed, apple orchards: an abandoned orchard undisturbed for 25 years, two ‘organically’ managed orchards, one with a cover crop of bell beans (Vicia faba) and grasses and the other kept clean of cover by discing, and a ‘commercial’ clean cultivated orchard sprayed with organophosphate insecticides. Six species of ants coexisted in the abandoned orchard, whereas only two species were found in the managed orchards. In both the organic and sprayed, clean cultivated systems, ants were more abundant in the orchard edges than in the vegetation-free centers. This trend was not apparent in the abandoned or organic cover orchards, where plant diversity in the center was similar to that of the edges. Ant predation on potato tuberworm larvae, Phthorimaea operculella, artificially placed on the orchard floor, declined with the intensity of management and vegetational simplication. A higher incidence of larval removal occurred in the edges than in the centers of the clean cultivated orchards. No noticeable populations of ants were detected on the trees in any of the orchards. Increased vegetational diversity and lack of disturbance appeared to affect ant locomotory activity and foraging efficiency by creating preferred sheltering and feeding sites. 相似文献