全文获取类型
收费全文 | 2645篇 |
免费 | 340篇 |
国内免费 | 2篇 |
专业分类
2987篇 |
出版年
2021年 | 26篇 |
2019年 | 28篇 |
2017年 | 27篇 |
2016年 | 35篇 |
2015年 | 45篇 |
2014年 | 77篇 |
2013年 | 93篇 |
2012年 | 110篇 |
2011年 | 93篇 |
2010年 | 84篇 |
2009年 | 77篇 |
2008年 | 108篇 |
2007年 | 116篇 |
2006年 | 99篇 |
2005年 | 106篇 |
2004年 | 111篇 |
2003年 | 72篇 |
2002年 | 88篇 |
2001年 | 79篇 |
2000年 | 79篇 |
1999年 | 63篇 |
1998年 | 56篇 |
1997年 | 42篇 |
1996年 | 33篇 |
1995年 | 30篇 |
1994年 | 30篇 |
1993年 | 26篇 |
1992年 | 65篇 |
1991年 | 64篇 |
1990年 | 56篇 |
1989年 | 64篇 |
1988年 | 52篇 |
1987年 | 47篇 |
1986年 | 40篇 |
1985年 | 49篇 |
1984年 | 44篇 |
1983年 | 36篇 |
1982年 | 33篇 |
1981年 | 27篇 |
1980年 | 27篇 |
1979年 | 31篇 |
1978年 | 27篇 |
1977年 | 25篇 |
1976年 | 35篇 |
1975年 | 33篇 |
1974年 | 26篇 |
1973年 | 24篇 |
1972年 | 39篇 |
1969年 | 25篇 |
1968年 | 24篇 |
排序方式: 共有2987条查询结果,搜索用时 15 毫秒
991.
Holder Peter E. Jeanson Amanda L. Lennox Robert J. Brownscombe Jacob W. Arlinghaus Robert Danylchuk Andy J. Bower Shannon D. Hyder Kieran Hunt Len M. Fenichel Eli P. Venturelli Paul A. Thorstad Eva B. Allen Micheal S. Potts Warren M. Clark-Danylchuk Sascha Claussen Julie E. Lyle Jeremy M. Tsuboi Jun-ichi Brummett Randall Freire Kátia M. F. Tracey Sean R. Skov Christian Cooke Steven J. 《Reviews in Fish Biology and Fisheries》2020,30(1):137-151
Reviews in Fish Biology and Fisheries - Recreational fisheries hold immense ecological, social, and economic value. The management of these fisheries is increasingly important as we move forward in... 相似文献
992.
Sweis RF Hunt JA Sinclair PJ Chen Y Eveland SS Guo Q Hyland SA Milot DP Cumiskey AM Latham M Rosa R Peterson L Sparrow CP Anderson MS 《Bioorganic & medicinal chemistry letters》2011,21(9):2597-2600
The development of 2-phenylbenzoxazoles as inhibitors of cholesteryl ester transfer protein (CETP) is described. Efforts focused on finding suitable replacements for the central piperidine with the aim of reducing hERG binding: a main liability of our benchmark benzoxazole (1a). Replacement of the piperidine with a cyclohexyl group successfully attenuated hERG binding, but was accompanied by reduced in vivo efficacy. The approach of substituting a piperidine moiety with an oxazolidinone also attenuated hERG binding. Further refinement of this latter scaffold via SAR at the pyridine terminus and methyl branching on the oxazolidinone led to compounds 7e and 7f, which raised HDLc by 33 and 27 mg/dl, respectively, in our transgenic mouse PD model and without the hERG liability of previous series. 相似文献
993.
Axel Martinelli Gisela Henriques Paul Hunt 《International journal for parasitology》2011,41(2):165-171
In malaria parasites, mutations in two genes of folate biosynthesis encoding dihydrofolate reductase (dhfr) and dihydropteroate synthase (dhps) modify responses to antifolate therapies which target these enzymes. However, the involvement of other genes which modify the availability of exogenous folate, for example, has been proposed. Here, we used short-read whole-genome re-sequencing to determine the mutations in a clone of the rodent malaria parasite, Plasmodium chabaudi, which has altered susceptibility to both sulphadoxine and pyrimethamine. This clone bears a previously identified S106N mutation in dhfr and no mutation in dhps. Instead, three additional point mutations in genes on chromosomes 2, 13 and 14 were identified. The mutated gene on chromosome 13 (mdr2 K392Q) encodes an ABC transporter. Because Quantitative Trait Locus analysis previously indicated an association of genetic markers on chromosome 13 with responses to individual and combined antifolates, MDR2 is proposed to modulate antifolate responses, possibly mediated by the transport of folate intermediates. 相似文献
994.
Ramathal C Wang W Hunt E Bagchi IC Bagchi MK 《The Journal of biological chemistry》2011,286(22):19860-19871
995.
The inhibitory effect of the fungal toxin, destruxin A, on behavioural fever in the desert locust 总被引:1,自引:0,他引:1
During an infection locusts behaviourally fever by seeking out higher environmental temperatures. This behaviour places the pathogen at sub-optimal growth temperatures while improving the efficiency of the immune system, thereby prolonging the lifespan of the host. It is therefore in the interest of the pathogen to either adapt to fever-like temperatures or to evolve mechanisms to interfere with, or inhibit fever. We investigated the behavioural fever response of desert locusts to two fungal pathogens. A prolonged fever was observed in locusts infected with Metarhizium acridum. However, fever was comparatively short-lived during infection with Metarhizium robertsii. In both cases restriction of thermoregulation reduced lifespan. Destruxin A (dtx A) produced by M. robertsii, but not M. acridum has previously been associated with the inhibition of the insect immune system. Injection of dtx A during infection with the fever-causing M. acridum inhibited fever and was particularly effective when administered early on in infection. Furthermore, locusts injected with dtx A were more susceptible to M. acridum infection. Therefore engineering M. acridum isolates currently used for locust biocontrol, to express dtx A may improve efficiency of control by interfering with fever. 相似文献
996.
Edgington S Buddie AG Moore D France A Merino L Hunt DJ 《Journal of helminthology》2011,85(4):381-394
A new Heterorhabditis species of entomopathogenic nematode was isolated from soil of the Atacama Desert in Chile. The new species is characterized by morphometrics of the infective juvenile (IJ) with length (L)?=?611 (578-666)?μm, head to excretory pore length (EP)?=?115 (101-126)?μm, tail?=?69 (62-79)?μm long, (EP/tail)?×?100 (E%)?=?165 (149-182) and L/maximum body diameter (ratio a)?=?28 (25-31). The male has spicules 45 (40-49)?μm long, gubernaculum 20 (17-22)?μm long and (spicule length/anal body diameter)?×?100 (SW%)?=?205 (179-249). The hermaphroditic adult has shallow cuticular folds immediately anterior and posterior to the vulva, a slight post-anal swelling and a finely rounded tail terminus. Morphologically, H. atacamensis n. sp. resembles H. safricana, H. marelatus, H. downesi and H. amazonensis, but can be distinguished by characters of adult and IJ stages. In particular, for adult males, H. atacamensis n. sp. differs from H. amazonensis by the number and orientation of the genital papillae and from H. downesi by the position of the excretory pore; by the shape of the female tail terminus from H. downesi and by the position of the IJ hemizonid from H. marelatus. Heterorhabditis atacamensis n. sp. is further characterized by internal transcribed spacer (ITS) and D2D3 rDNA sequences, the closest species, H. safricana, being separated by 13?bp across 730?bp of the ITS (incorporating ITS1 (partial sequence), 5.8S (complete sequence), ITS2 (complete sequence)) and 5?bp across 592?bp of the partial 28S (incorporating D2D3) sequence. The morphological and molecular data confirm that H. atacamensis n. sp. is a valid species. 相似文献
997.
Kuwabara A Backhaus A Malinowski R Bauch M Hunt L Nagata T Monk N Sanguinetti G Fleming A 《Plant physiology》2011,156(4):2196-2206
Understanding the relationship of the size and shape of an organism to the size, shape, and number of its constituent cells is a basic problem in biology; however, numerous studies indicate that the relationship is complex and often nonintuitive. To investigate this problem, we used a system for the inducible expression of genes involved in the G1/S transition of the plant cell cycle and analyzed the outcome on leaf shape. By combining a careful developmental staging with a quantitative analysis of the temporal and spatial response of cell division pattern and leaf shape to these manipulations, we found that changes in cell division frequency occurred much later than the observed changes in leaf shape. These data indicate that altered cell division frequency cannot be causally involved in the observed change of shape. Rather, a shift to a smaller cell size as a result of the genetic manipulations performed correlated with the formation of a smoother leaf perimeter, i.e. appeared to be the primary cellular driver influencing form. These data are discussed in the context of the relationship of cell division, growth, and leaf size and shape. 相似文献
998.
999.
1000.