全文获取类型
收费全文 | 181篇 |
免费 | 10篇 |
出版年
2022年 | 1篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 4篇 |
2017年 | 1篇 |
2015年 | 5篇 |
2014年 | 6篇 |
2013年 | 9篇 |
2012年 | 4篇 |
2011年 | 6篇 |
2010年 | 5篇 |
2009年 | 10篇 |
2008年 | 16篇 |
2007年 | 11篇 |
2006年 | 7篇 |
2005年 | 11篇 |
2004年 | 18篇 |
2003年 | 11篇 |
2002年 | 13篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 5篇 |
1998年 | 6篇 |
1997年 | 5篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 5篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有191条查询结果,搜索用时 31 毫秒
61.
62.
63.
64.
Shumpei Kitamura Takakazu Yumoto Naohiko Noma Phitaya Chuailua Tamaki Maruhashi Prawat Wohandee Pilai Poonswad 《Ecological Research》2008,23(6):943-952
Hornbills (Bucerotidae) are widely regarded as important seed dispersers in tropical forests in Africa and Asia. We investigated
how the roosting behavior of wreathed hornbills (Aceros undulatus) influences seed deposition and seedling survival at a roost site in a moist evergreen forest of Khao Yai National Park,
Thailand. Fallen fruits and seeds were collected in traps that were placed around a roosting site for 14 months, and seedlings
were monitored in adjacent quadrats for 3 years. Seedfall and seedlings of species represented in the hornbill diet occurred
at significantly higher densities in the traps and quadrats located beneath the crown of the roosting tree than in those located
beyond the crown. With the exception of Cinnamomum subavenium, the seeds and seedlings of most diet species rarely survived beyond the first year. The quality of hornbill dispersal to
this roosting site may be poor due to the highly concentrated seedfall, which results in high seed and seedling mortality.
However, the number of seeds deposited by each hornbill each day at roosting sites is relatively low. Wreathed hornbills are
primarily scatter dispersers during the day and probably serve as agents of seed dispersal in the moist evergreen forest of
Khao Yai. 相似文献
65.
Takakazu Nakabayashi Issei Nagao Masataka Kinjo Yumiko Aoki Minoru Tanaka Nobuhiro Ohta 《Photochemical & photobiological sciences》2008,7(6):671-674
The fluorescence lifetime image of HeLa cells expressing an enhanced green fluorescent protein (EGFP)-fusion protein changes under stress, which allows noninvasive determination of the status of individual cells. 相似文献
66.
67.
Chang HC Dimlich DN Yokokura T Mukherjee A Kankel MW Sen A Sridhar V Fulga TA Hart AC Van Vactor D Artavanis-Tsakonas S 《PloS one》2008,3(9):e3209
Spinal Muscular Atrophy (SMA), a recessive hereditary neurodegenerative disease in humans, has been linked to mutations in the survival motor neuron (SMN) gene. SMA patients display early onset lethality coupled with motor neuron loss and skeletal muscle atrophy. We used Drosophila, which encodes a single SMN ortholog, survival motor neuron (Smn), to model SMA, since reduction of Smn function leads to defects that mimic the SMA pathology in humans. Here we show that a normal neuromuscular junction (NMJ) structure depends on SMN expression and that SMN concentrates in the post-synaptic NMJ regions. We conducted a screen for genetic modifiers of an Smn phenotype using the Exelixis collection of transposon-induced mutations, which affects approximately 50% of the Drosophila genome. This screen resulted in the recovery of 27 modifiers, thereby expanding the genetic circuitry of Smn to include several genes not previously known to be associated with this locus. Among the identified modifiers was wishful thinking (wit), a type II BMP receptor, which was shown to alter the Smn NMJ phenotype. Further characterization of two additional members of the BMP signaling pathway, Mothers against dpp (Mad) and Daughters against dpp (Dad), also modify the Smn NMJ phenotype. The NMJ defects caused by loss of Smn function can be ameliorated by increasing BMP signals, suggesting that increased BMP activity in SMA patients may help to alleviate symptoms of the disease. These results confirm that our genetic approach is likely to identify bona fide modulators of SMN activity, especially regarding its role at the neuromuscular junction, and as a consequence, may identify putative SMA therapeutic targets. 相似文献
68.
Complete genome structure of the thermophilic cyanobacterium Thermosynechococcus elongatus BP-1. 总被引:6,自引:0,他引:6
Yasukazu Nakamura Takakazu Kaneko Shusei Sato Masahiko Ikeuchi Hiroshi Katoh Shigemi Sasamoto Akiko Watanabe Mayumi Iriguchi Kumiko Kawashima Takaharu Kimura Yoshie Kishida Chiaki Kiyokawa Mitsuyo Kohara Midori Matsumoto Ai Matsuno Naomi Nakazaki Sayaka Shimpo Masako Sugimoto Chie Takeuchi Manabu Yamada Satoshi Tabata 《DNA research》2002,9(4):123-130
69.
Age and growth of Lestrolepis japonica (Aulopiformes: Paralepididae) in Kagoshima Bay,southern Japan
Age and growth of a paralepidid, Lestrolepis japonica, were determined from sagittal otoliths of specimens collected from April 2001 to February 2002 in Kagoshima Bay, southern
Japan. Marginal growth increments indicated that the annulus was formed once a year, in August and September. Four groups
were recognized, having none, one, two, or three annuli, respectively. Age in months was assigned to each individual on the
basis of August as the birth month. The maximum recorded age was 48 months. Growth was expressed by von Bertalanffy's equation,
L
t
= 171.91{1 − exp[−0.148(t + 0.403)]}, t being the age in months and L
t
the standard length (mm) at age t.
Received: July 15, 2002 / Revised: November 18, 2002 / Accepted: December 10, 2002 相似文献
70.
Shoko Sakai Kuniyasu Momose Takakazu Yumoto Teruyoshi Nagamitsu Hidetoshi Nagamasu Abang A. Hamid Tohru Nakashizuka 《American journal of botany》1999,86(10):1414-1436
The first systematic observation of a general flowering, a phenomenon unique to lowland mixed-dipterocarp forests in Southeast Asia, is presented. During general flowering, which occurs at irregular intervals of 3–10 yr, nearly all dipterocarp species together with species of other families come heavily into flower. We monitored reproductive phenology of 576 individual plants representing 305 species in 56 families in Sarawak, Malaysia. Observations continued for 53 mo from August 1992 and covered one episode of a general flowering cycle. Among 527 effective reproductive events during 43 mo, 57% were concentrated in the general flowering period (GFP) of 10 mo in 1996. We classified 257 species into flowering types based on timing and frequency of flowering. The most abundant type was “general flowering” (35%), which flowered only during GFP. The others were “supra-annual” (19%), “annual” (13%), and “sub-annual” (5%) types. General flowering type and temporal aggregation in reproductive events were commonly found among species in various categories of taxonomic groups, life forms, pollination systems, and fruit types. Possible causes for general flowering, such as promotion of pollination brought about by interspecific synchronization and paucity of climatic cues suitable for flowering trigger, are proposed, in addition to the predator satiation hypothesis of Janzen (1974) . 相似文献