全文获取类型
收费全文 | 85865篇 |
免费 | 7580篇 |
国内免费 | 43篇 |
专业分类
93488篇 |
出版年
2023年 | 281篇 |
2022年 | 707篇 |
2021年 | 1548篇 |
2020年 | 879篇 |
2019年 | 1108篇 |
2018年 | 1439篇 |
2017年 | 1241篇 |
2016年 | 2136篇 |
2015年 | 3630篇 |
2014年 | 4047篇 |
2013年 | 4812篇 |
2012年 | 6537篇 |
2011年 | 6482篇 |
2010年 | 4170篇 |
2009年 | 3798篇 |
2008年 | 5428篇 |
2007年 | 5431篇 |
2006年 | 5233篇 |
2005年 | 5031篇 |
2004年 | 4891篇 |
2003年 | 4668篇 |
2002年 | 4401篇 |
2001年 | 858篇 |
2000年 | 622篇 |
1999年 | 959篇 |
1998年 | 1230篇 |
1997年 | 821篇 |
1996年 | 742篇 |
1995年 | 653篇 |
1994年 | 616篇 |
1993年 | 666篇 |
1992年 | 553篇 |
1991年 | 520篇 |
1990年 | 461篇 |
1989年 | 397篇 |
1988年 | 420篇 |
1987年 | 342篇 |
1986年 | 317篇 |
1985年 | 399篇 |
1984年 | 518篇 |
1983年 | 401篇 |
1982年 | 501篇 |
1981年 | 486篇 |
1980年 | 414篇 |
1979年 | 295篇 |
1978年 | 323篇 |
1977年 | 281篇 |
1976年 | 263篇 |
1975年 | 204篇 |
1974年 | 241篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
62.
63.
Krajana Tainchum Wanapa Ritthison Thipwara Chuaycharoensuk Michael J. Bangs Sylvie Manguin Theeraphap Chareonviriyaphap 《Journal of vector ecology》2014,39(2):424-436
We determined the species diversity, blood‐feeding behavior, and host preference of Anopheles mosquitoes in two malaria endemic areas of Tak (Mae Sot District) and Mae Hong Son (Sop Moei District) Provinces, located along the Thai border with Myanmar, during a consecutive two‐year period. Anopheline mosquitoes were collected using indoor and outdoor human‐landing captures and outdoor cow‐baited collections. Mosquitoes were initially identified using morphological characters, followed by the appropriate multiplex AS‐PCR assay for the identification of sibling species within Anopheles (Cellia) complexes and groups present. Real‐time PCR was performed for parasite‐specific detection in mosquitoes (Plasmodium spp. and Wuchereria bancrofti). A total of 7,129 Anopheles females were captured, 3,939 from Mae Sot and 3,190 from Sop Moei, with 58.6% and 37% of all anophelines identified as An. minimus, respectively. All three malaria vector complexes were detected in both areas. One species within the Minimus Complex (An. minimus) was present along with two related species in the Funestus Group, (An. aconitus, An. varuna), two species within the Dirus Complex (An. dirus, An. baimaii), and four species within the Maculatus Group (An. maculatus, An. sawadwongporni, An. pseudowillmori, and An. dravidicus). The trophic behavior of An. minimus, An. dirus, An. baimaii, An. maculatus, and An. sawadwongporni are described herein. The highest An. minimus densities were detected from February through April of both years. One specimen of An. minimus from Mae Sot was found positive for Plasmodium vivax. 相似文献
64.
Amy Chapman Gonzalo Gonzales Wayne R. Burrowes Paul Assanah Bernadette Iannone Michael K. Leung George B. Stefano 《Cellular and molecular neurobiology》1984,4(2):143-155
In Mytilus and Leucophaea the high-affinity binding site density is significantly lower in old animals than in young animals, whereas the low-affinity site density remains unchanged. In Mytilus the estimated met-enkephalin and met-enkephalin-Arg6-Phe7 levels are significantly higher in old than in young animals. In Leucophaea only the met-enkephalin level can be determined, and it is also higher in old animals. The decrease in the high-affinity binding site density and the corresponding increase in endogenous enkephalin levels suggest the existence of an opioid compensatory mechanism associated with the aging process. In Mytilus there is a demonstrated decrease with age in intraganglionic dopamine levels in response to applied opiates. In addition, the inhibition of dopamine-stimulated adenylate cyclase activity by opiates also decreases in older animals. In Leucophaea the sex difference in opioid binding densities diminishes with age. 相似文献
65.
Plasma choline concentrations were measured in humans, rats, and rabbits within the first few hours of life, before any food was ingested. Neonatal animals and humans had markedly elevated plasma choline levels compared to adult animals or humans. Possible mechanisms responsible for this elevation are discussed and possible consequences for brain function, lung function, and growth are presented. 相似文献
66.
67.
68.
The mapping of genetic loci within organisms has been accelerated by the advent of Radiation Hybrid (RH) panels. These panels
are available for humans and non-humans including mice, baboon, rat, and canine. This article contains a general protocol
for the use of the Genebridge 4 whole genome RH panel to map a human locus. This protocol may also be adjusted to suit the
other RH panels currently available. 相似文献
69.
70.
Climatic forcing and larval dispersal capabilities shape the replenishment of fishes and their habitat‐forming biota on a tropical coral reef
下载免费PDF全文
![点击此处可从《Ecology and evolution》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Shaun K. Wilson Martial Depcyznski Rebecca Fisher Thomas H. Holmes Mae M. Noble Ben T. Radford Michael Rule George Shedrawi Paul Tinkler Christopher J. Fulton 《Ecology and evolution》2018,8(3):1918-1928
Fluctuations in marine populations often relate to the supply of recruits by oceanic currents. Variation in these currents is typically driven by large‐scale changes in climate, in particular ENSO (El Nino Southern Oscillation). The dependence on large‐scale climatic changes may, however, be modified by early life history traits of marine taxa. Based on eight years of annual surveys, along 150 km of coastline, we examined how ENSO influenced abundance of juvenile fish, coral spat, and canopy‐forming macroalgae. We then investigated what traits make populations of some fish families more reliant on the ENSO relationship than others. Abundance of juvenile fish and coral recruits was generally positively correlated with the Southern Oscillation Index (SOI), higher densities recorded during La Niña years, when the ENSO‐influenced Leeuwin Current is stronger and sea surface temperature higher. The relationship is typically positive and stronger among fish families with shorter pelagic larval durations and stronger swimming abilities. The relationship is also stronger at sites on the coral back reef, although the strongest of all relationships were among the lethrinids (r = .9), siganids (r = .9), and mullids (r = .8), which recruit to macroalgal meadows in the lagoon. ENSO effects on habitat seem to moderate SOI–juvenile abundance relationship. Macroalgal canopies are higher during La Niña years, providing more favorable habitat for juvenile fish and strengthening the SOI effect on juvenile abundance. Conversely, loss of coral following a La Niña‐related heat wave may have compromised postsettlement survival of coral dependent species, weakening the influence of SOI on their abundance. This assessment of ENSO effects on tropical fish and habitat‐forming biota and how it is mediated by functional ecology improves our ability to predict and manage changes in the replenishment of marine populations. 相似文献