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41.
MICHAEL F. FAY
fls JAMES J. CLARKSON PETER GASSON
fls JULIO MORALES CAN JORGE B. JIMÉNEZ BARRIOS MARK W. CHASE
fls 《Botanical journal of the Linnean Society. Linnean Society of London》2010,164(1):16-25
Petenaea cordata (from northern Central America) was first described in Elaeocarpaceae and later placed in Tiliaceae, but most authors have been uncertain about its familial affinities. It was considered a taxon incertae sedis in the Angiosperm Phylogeny Group classification (APG III). A recent collection was made in Guatemala, and analysis of both rbcL and atpB in the large Soltis et al. angiosperm matrix, the most completely sampled study published to date, indicated a moderately supported relationship to Tapiscia (Tapisciaceae, the only member of the newly recognized order Huerteales in this matrix; 81% bootstrap support). We then conducted a more restricted analysis using the Bayer et al. rbcL/atpB matrix for Malvales supplemented with the other genera of Huerteales from published studies. Our results indicate a distant, weakly supported sister‐group relationship to the African genus Gerrardina (Gerrardinaceae; Huerteales). After comparison of the characters cited in the literature and an examination of herbarium material of both genera, we could find no obvious synapomorphies for Gerrardina and Petenaea or any other relationship of the latter, and we therefore propose the new monogeneric family, Petenaeaceae. The polymorphic order Huerteales now comprises four small families: Dipentodontaceae, Gerrardinaceae, Petenaeaceae and Tapisciaceae. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 164 , 16–25. 相似文献
42.
DAVID E. AUSBAND MICHAEL S. MITCHELL KEVIN DOHERTY PETER ZAGER CURT M. MACK JIM HOLYAN 《The Journal of wildlife management》2010,74(5):1043-1049
ABSTRACT We used rendezvous site locations of wolf (Canis lupus) packs recorded during 1996–2006 to build a predictive model of gray wolf rendezvous site habitat in Idaho, USA. Variables in our best model included green leaf biomass (Normalized Difference Vegetation Index), surface roughness, and profile curvature, indicating that wolves consistently used wet meadow complexes for rendezvous sites. We then used this predictive model to stratify habitat and guide survey efforts designed to document wolf pack distribution and fecundity in 4 study areas in Idaho. We detected all 15 wolf packs (32 wolf pack-yr) and 20 out of 27 (74%) litters of pups by surveying <11% of the total study area. In addition, we were able to obtain detailed observations on wolf packs (e.g., hair and scat samples) once we located their rendezvous sites. Given an expected decrease in the ability of managers to maintain radiocollar contact with all of the wolf packs in the northern Rocky Mountains, rendezvous sites predicted by our model can be the starting point and foundation for targeted sampling and future wolf population monitoring surveys. 相似文献
43.
A metabolomic study in oats (Avena sativa) highlights a drought tolerance mechanism based upon salicylate signalling pathways and the modulation of carbon,antioxidant and photo‐oxidative metabolism 下载免费PDF全文
JAVIER SÁNCHEZ‐MARTÍN JIM HEALD ALISON KINGSTON‐SMITH ANA WINTERS DIEGO RUBIALES MARILUZ SANZ LUIS A. J. MUR ELENA PRATS 《Plant, cell & environment》2015,38(7):1434-1452
Although a wealth of information is available on the induction of one or several drought‐related responses in different species, little is known of how their timing, modulation and crucially integration influence drought tolerance. Based upon metabolomic changes in oat (Avena sativa L.), we have defined key processes involved in drought tolerance. During a time course of increasing water deficit, metabolites from leaf samples were profiled using direct infusion–electrospray mass spectroscopy (DI‐ESI‐MS) and high‐performance liquid chromatography (HPLC) ESI‐MS/MS and analysed using principal component analysis (PCA) and discriminant function analysis (DFA). The involvement of metabolite pathways was confirmed through targeted assays of key metabolites and physiological experiments. We demonstrate an early accumulation of salicylic acid (SA) influencing stomatal opening, photorespiration and antioxidant defences before any change in the relative water content. These changes are likely to maintain plant water status, with any photoinhibitory effect being counteracted by an efficient antioxidant capacity, thereby representing an integrated mechanism of drought tolerance in oats. We also discuss these changes in relation to those engaged at later points, consequence of the different water status in susceptible and resistant genotypes. 相似文献
44.
JIM MRACEK STEPHANIE J. SNYDER ULISES B. CHAVEZ JULIO F. TURRENS 《The Journal of eukaryotic microbiology》1991,38(6):554-558
ABSTRACT. The enzyme NADH-fumarate reductase associated with the membrane fraction of Trypanosoma brucei procyclic trypomastigotes, can be solubilized by more than 50% when increasing the ionic strength to the equivalent of 150 mM KCI. The apparent KM s for NADH (125 μM) and fumarate (50 μM) remain close to those previously reported for the membrane-bound form of this enzyme. Other electron acceptors (i.e. oxygen or cytochrome c) appear to accept electrons in the absence of fumarate (KM for cytochrome c = 50 μM). The drug L-092,201 (Merck, Sharp and Dohme Research Laboratories, Rahway, NJ), an inhibitor of the membrane-bound fumarate reductase, also blocked the solubilized enzyme. Given the relatively high ionic strength of the intracellular environment we propose that, in vivo, the enzyme fumarate reductase is in the mitochondrial matrix or in the soluble fraction of another intracellular compartment. 相似文献
45.
ARNAUD BRAYARD HUGO BUCHER THOMAS BRÜHWILER THOMAS GALFETTI NICOLAS GOUDEMAND KUANG GUODUN GILLES ESCARGUEL JIM JENKS 《Lethaia: An International Journal of Palaeontology and Stratigraphy》2007,40(2):175-181
Based on new, bed-rock controlled material from northwestern Guangxi and Oman, the Early Triassic genus Proharpoceras Chao is shown to be a representative of Otocerataceae. Character analysis excludes a direct link with the Griesbachian Otoceratidae and favours a derivation of Proharpoceras from the late Permian Anderssonoceratidae. The biostratigraphic range of Proharpoceras is restricted to the Smithian and its biogeographic distribution comprises Oman, South China, and Primorye, thus indicating an essentially low palaeolatitudinal distribution. Proharpoceras has no apparent relatives among other Early and Middle Triassic Ceratitida and is thus considered to be the last representative of Otocerataceae. This offshoot of the late Permian Anderssonoceratidae implies that an additional ammonoid lineage survived the end Permian extinction and that it dwindled away for some 2 Myr before going extinct. 相似文献
46.
DAVID B. LINDENMAYER PHILIP GIBBONS MAX BOURKE MARK BURGMAN CHRIS R. DICKMAN SIMON FERRIER JAMES FITZSIMONS DAVID FREUDENBERGER STEPHEN T. GARNETT CRAIG GROVES RICHARD J. HOBBS RICHARD T. KINGSFORD CHARLES KREBS SARAH LEGGE ANDREW J. LOWE ROB MCLEAN JENSEN MONTAMBAULT HUGH POSSINGHAM JIM RADFORD DOUG ROBINSON LISA SMALLBONE DAVID THOMAS TONY VARCOE MICHAEL VARDON GLENDA WARDLE ANDRE ZERGER 《Austral ecology》2012,37(3):285-294
Effective biodiversity monitoring is critical to evaluate, learn from, and ultimately improve conservation practice. Well conceived, designed and implemented monitoring of biodiversity should: (i) deliver information on trends in key aspects of biodiversity (e.g. population changes); (ii) provide early warning of problems that might otherwise be difficult or expensive to reverse; (iii) generate quantifiable evidence of conservation successes (e.g. species recovery following management) and conservation failures; (iv) highlight ways to make management more effective; and (v) provide information on return on conservation investment. The importance of effective biodiversity monitoring is widely recognized (e.g. Australian Biodiversity Strategy). Yet, while everyone thinks biodiversity monitoring is a good idea, this has not translated into a culture of sound biodiversity monitoring, or widespread use of monitoring data. We identify four barriers to more effective biodiversity monitoring in Australia. These are: (i) many conservation programmes have poorly articulated or vague objectives against which it is difficult to measure progress contributing to design and implementation problems; (ii) the case for long‐term and sustained biodiversity monitoring is often poorly developed and/or articulated; (iii) there is often a lack of appropriate institutional support, co‐ordination, and targeted funding for biodiversity monitoring; and (iv) there is often a lack of appropriate standards to guide monitoring activities and make data available from these programmes. To deal with these issues, we suggest that policy makers, resource managers and scientists better and more explicitly articulate the objectives of biodiversity monitoring and better demonstrate the case for greater investments in biodiversitymonitoring. There is an urgent need for improved institutional support for biodiversity monitoring in Australia, for improved monitoring standards, and for improved archiving of, and access to, monitoring data. We suggest that more strategic financial, institutional and intellectual investments in monitoring will lead to more efficient use of the resources available for biodiversity conservation and ultimately better conservation outcomes. 相似文献
47.
Schellackia occidentalis n.sp., a Blood-inhabiting Coccidian Found in Lizards in Southern California
SUMMARY. Schellackia occidentalis n. sp., is described from the following lizards from southern California: Sceloporus occidentalis becki, S. o. biseriatus , and Uta stansburiana hesperis. Evidence is presented to show that lizards become infected by ingestion of the lizard mite Geckobiella texana. The mite acts as a passive vector by swallowing infected erythrocytes. After ingestion of the mites carrying parasitized red cells, the lizard is infected by migration of the sporozoites into the lizard's intestinal epithelial cells. Schizogony and sporogony occur in the intestinal wall of the lizard. Sporozoites appear in the peripheral blood from 30 to 45 days after ingestion of infected mites. This is the first species of the genus Schellackia to be described in the Western Hemisphere. 相似文献
48.
Behavioural evidence for detection of the repellent polygodial by aphid antennal tip sensilla 总被引:1,自引:0,他引:1
Abstract. Close-up video was used to record responses of the aphid Myzus persicae (Sulzer) (Homoptera: Aphididae) to the plant-derived repellent polygodial. When 0.1% (±)-polygodial was painted onto one half of a Chinese cabbage leaf disc, and the other half treated with the ethanol solvent, apterous adult aphids avoided walking onto the polygodial-treated area during 15 min access periods. Similarly, when the rim of a small plastic Petri dish was treated with polygodial, aphids took significantly longer to walk off the base of the dish and onto the rim, compared with insects in solvent-treated control dishes. Analysis of video-recordings indicated that aphids were repelled following contact of antennal tips with the polygodial-treated areas of leaf or plastic. In contrast, aphids with both antennal tips surgically removed showed no apparent response to polygodial treatment of leaf or plastic surfaces. Aphids were placed between polygodial- and solvent-treated angled glass cover slips to enable unilateral presentation of polygodial on either the left or right side of the insects. Most aphids with antennae intact moved away from the polygodial-treated side, but removal of both antennal tips again negated the response. When the tip was removed from only one antenna, and the other remained intact, unilateral presentation caused a repellent response only if polygodial occurred on the same side as the intact antenna. Presentation of polygodial on both sides of aphids (bilaterally) caused no response if both antennal tips were intact or removed, but aphids with only one antennal tip removed were repelled from the side where the antenna remained intact. The results indicate that aphids detect polygodial upon contact with sensilla located on the antennal tips, and that the repellent response occurs as a negative chemotropotaxis following unilateral stimulation of these sensilla. Contact between the antennal tips and glass substrates was demonstrated using a fluorescent pigment. 相似文献
49.
50.
Abstract 1. Seasonal variation in immune response has rarely been investigated in invertebrates and, therefore, we have studied this using territorial adult males of the damselfly, Hetaerina americana (Fabricius), in several generations, for a year and a half. 2. We investigated and related seasonal variation in red pigmented wing spot size (an ornamental trait) and body size to fat reserves using four immunity components – melanisation ability, phenoloxidase (PO) and nitric oxide (NO) activity, and haemolymph protein concentration – and survival ability after a bacterial immune challenge. 3. There was seasonal variation in spot expression, being more intense in the non‐winter months and less intense in winter months, and, to some extent, a similar pattern was found for NO. Although there was also variation in melanisation, PO activity, protein concentration and fat reserves, this was not consistently related to variation in spot size. Survival was lower in the winter than in non‐winter months. 4. Animals with larger spot and body size had greater values of melanisation, PO and NO activity, and protein concentration. The relation of spot and body size with fat reserves is still not clear. 5. Unlike other studies, ornament was not similarly correlated with all typical immune components (at best, mainly NO). 6. Similar to what occurs in vertebrates, survival is lower during the winter months. In the case of vertebrate studies, however, the same individual suffers these changes. In the American rubyspot, distinct cohorts demonstrated seasonal differences. 相似文献