全文获取类型
收费全文 | 44758篇 |
免费 | 3635篇 |
国内免费 | 6篇 |
出版年
2023年 | 225篇 |
2021年 | 324篇 |
2020年 | 296篇 |
2019年 | 286篇 |
2018年 | 892篇 |
2017年 | 924篇 |
2016年 | 972篇 |
2015年 | 804篇 |
2014年 | 942篇 |
2013年 | 1795篇 |
2012年 | 3051篇 |
2011年 | 3427篇 |
2010年 | 1730篇 |
2009年 | 1100篇 |
2008年 | 2837篇 |
2007年 | 2899篇 |
2006年 | 2718篇 |
2005年 | 2440篇 |
2004年 | 2361篇 |
2003年 | 2214篇 |
2002年 | 2193篇 |
2001年 | 1505篇 |
2000年 | 1752篇 |
1999年 | 918篇 |
1998年 | 424篇 |
1997年 | 347篇 |
1996年 | 415篇 |
1995年 | 355篇 |
1994年 | 379篇 |
1993年 | 340篇 |
1992年 | 364篇 |
1991年 | 301篇 |
1990年 | 278篇 |
1989年 | 258篇 |
1988年 | 252篇 |
1987年 | 251篇 |
1986年 | 212篇 |
1985年 | 310篇 |
1984年 | 374篇 |
1983年 | 336篇 |
1982年 | 312篇 |
1981年 | 301篇 |
1980年 | 272篇 |
1979年 | 259篇 |
1978年 | 264篇 |
1977年 | 243篇 |
1976年 | 245篇 |
1975年 | 290篇 |
1974年 | 212篇 |
1973年 | 203篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.
5.
In a section of the Liassic southwest of the village of Préjano (Prov. Logroño) Sinemurian Dasyclad algae were found for the first time in the “Bankkalk-Series” of the “Carniolas-Formation” which is not dated up to that time. Six species,Dissocladella lucasi (Cros & Lemoine),Dissocladella iberica nov. sp.,Dissocladella ebroensis nov. sp.,Sestrosphaera liasina Pia,Gyroporella retica (Zanin) andMacroporella nov. sp. aff. sturi Bystricky are described. 相似文献
6.
7.
8.
Georg Söderbom 《Ethnos》2013,78(1-2):95-100
Current debates over the concept of culture are examined, especially with regard to the relationship of culture to bounded collectivities, human nature, and individuality; present‐day views are seen against the background of back‐and‐forth swings in the history of anthropological thought. Recent theorizing about cultural acquisition is also considered. 相似文献
9.
10.
Yuji Inaba Yoshio Tanaka Sukemitsu Ishii Tomiaki Morimoto Kunihiko Sato Tuneyoshi Omori Minoru Matumoto 《Microbiology and immunology》1970,14(5):351-360
Replication of Ibaraki virus was not inhibited by 5-iodo-2′-deoxyuridine, indicating that the virus is an RNA virus. The virus was resistant to ether, chloroform and deoxycholate, sensitive to trypsin, very labile at acidic pH but stable at pH 6.4 or higher, and was resistant to repeated freezing and thawing. The virus was readily inactivated at 56 C or higher, was fairly stable at 37 C, and very stable at 4 C, while it rapidly lost infectivity when stored frozen at —20 C. The virus was readily sedimented by centrifugation at 40 000Xg for 60 min. It readily passed through membrane filters of 200 mμ pore size, passed through 100 μfilters but only with some titer loss and did not through 50 mμ filters. In these tests, the bluetongue virus used as a control behaved in the same manner as Ibaraki virus. These findings provide additional evidence for the similarity of Ibaraki virus to bluetongue virus which had been previously demonstrated on the basis of seasonal incidence, symptomatology and pathology of the diseases caused by these viruses and the behavior of the viruses in cell cultures, embryonated eggs and laboratory animals. The present study, however, provided no evidence for any serological relation between these two viruses. More Information is needed to reach a final decision on the classification of Ibaraki virus, particularly regarding the morphology of the virion, the doublestrandedness of the viral RNA and other basic features. 相似文献