全文获取类型
收费全文 | 810篇 |
免费 | 21篇 |
国内免费 | 67篇 |
出版年
2015年 | 10篇 |
2013年 | 17篇 |
2012年 | 20篇 |
2011年 | 27篇 |
2010年 | 33篇 |
2009年 | 46篇 |
2008年 | 33篇 |
2007年 | 53篇 |
2006年 | 42篇 |
2005年 | 35篇 |
2004年 | 28篇 |
2003年 | 35篇 |
2002年 | 29篇 |
2001年 | 14篇 |
1999年 | 7篇 |
1998年 | 8篇 |
1997年 | 13篇 |
1996年 | 16篇 |
1995年 | 17篇 |
1993年 | 14篇 |
1992年 | 16篇 |
1991年 | 11篇 |
1990年 | 14篇 |
1989年 | 13篇 |
1988年 | 12篇 |
1987年 | 11篇 |
1986年 | 8篇 |
1985年 | 10篇 |
1984年 | 7篇 |
1983年 | 7篇 |
1981年 | 6篇 |
1980年 | 9篇 |
1978年 | 10篇 |
1977年 | 8篇 |
1976年 | 10篇 |
1975年 | 7篇 |
1974年 | 15篇 |
1973年 | 6篇 |
1972年 | 7篇 |
1971年 | 11篇 |
1966年 | 6篇 |
1959年 | 9篇 |
1958年 | 18篇 |
1957年 | 18篇 |
1956年 | 10篇 |
1955年 | 16篇 |
1954年 | 17篇 |
1953年 | 11篇 |
1952年 | 8篇 |
1951年 | 9篇 |
排序方式: 共有898条查询结果,搜索用时 15 毫秒
811.
Bong‐Woo LEE Yang‐Seop BAE Ah Reum HAN Pil Sun PARK Bong‐Kyu BYUN 《Entomological Research》2011,41(6):264-268
The adult and the early stages of Cydia piceicola, sp. nov., are described and illustrated from Korea. Larvae of the new species feed on Picea jezoensis (Siebold et Zucc.) Carrière, The life history and larval feeding habits are briefly discussed. 相似文献
812.
Twelve species of the genus Aulacorthum Mordvilko 1914 (Sternorrhyncha: Aphididae) are recognized from the Korean Peninsula. One new species, Aulacorthum ixeridis n. sp., is described for apterous and alate viviparous females on Ixeris chinensis var. graminifolia (Ledeb.) H. C. Fu and Lactuca indica L. (Asteraceae). From the allied species, Aulacorthum nepetifolii Miyazaki 1968, Aulacorthum ixeridis n. sp. is distinguished by the relatively short ultimate rostral segment (0.83–1.07 × as long as the second segment hind tarsus), the dense spinules on head and the triangular short cauda. Host plants of the Korean Aulacorthum are reviewed and the identification key to subgenera and species is also presented. 相似文献
813.
D.W. LEE J. B. LOWRY 《Botanical journal of the Linnean Society. Linnean Society of London》1980,80(3):223-242
The genus Leptospermum (Mytaceae) is represented on Mount Kinabalu, Borneo, by L.flavescens (widespread on Malesian mountains and uplands) and L.recurvum (endemic to Mount Kinabalu). Analysis of the general morphology, leaf characters, leaf anatomy and flavonoid content of field collection, of both taxa at 1970–4000 m indicated that L.recuruum is a distinct species, most probably derived from L.flavescenS. L.recurvum individuals display a striking variation in leaf pubescence. Seedlings of. These plants grown under uniform conditions were not genetically variable (as seen in the uniformity of peroxidase and acid phosphatase isozymes).Variation that did occur was not correlated with altitude or any other identifiable ecological factors. The sporadic distribution of individuals producing non-viable seeds, probably an expression of genetic load, is another indication of a lack of genetic diversity. L.recurvum may have evolved from a population of L.flaurscens on Mount Kinabalu, most probably during the Pleistocene. 相似文献
814.
Variations in Root Water Potentials: Influence of Environmental Factors for Two Succulent Species 总被引:1,自引:0,他引:1
Average root water potential ( 相似文献
815.
816.
817.
818.
SYNOPSIS. A polymorphic allogromiid (our strain NF) was isolated in monoxenic culture but attempts at its axenic culture failed. Growth of monoxenic cultures was stimulated by various metals and vitamins. The morphology and life cycle of this allogromiid with a prominent collar have been studied in detail. It varied in form from ovoid to elongate bioral "Shepheardella-like" forms and to irregular polyoral organisms. The organisms ranged in length from 56–385 μ (118 μ± 50.54) and in width from 35–385 μ (99 μ± 39.34). The number of nuclei per organism averaged 8.9 ± 6.3 (range 1–40). Reproduction of " Shepheardella -like" forms was by binary fission. Three types of budding have been observed and, rarely, schizogony. No evidence for sexual reproduction has thus far been seen. 相似文献
819.
820.
The effect of a genetically engineered Pseudomonas aureofaciens (Ps3732RNL11) strain (GEM) and the parental wild-type (Ps3732RN) on decomposition of cellulose paper, straw and calico cloth was assessed after 18 weeks incubation in laboratory soil microcosms. Effect(s) of inoculum density (103, 105, and 108 cells/ g dry soil) and single versus multiple bacterial inoculations were also investigated. Cellulose paper was completely decomposed after 18 weeks in all treatments. There were no significant differences (95% level), between treatments, in percentage decomposition of either straw or calico cloth. Recovery of the GEM at 18 weeks, using viable plating, was limited to treatments originally receiving 108 cells/g dry soil. Log 1.8 CFU/g dry soil were recovered from the single dose treatment while log 4.2 CFU/g dry soil were recovered from the multiple dose treatment Biolog metabolic tests were used to determine if the GEM or parental wild-type had any effect on overall carbon utilization in soil. Results suggested they did not. Detection of the recombinant lacZY gene sequence in soil using PCR suggested the possibility of viable but nonculturable cells and/or persistence of chromosomal DNA. 相似文献