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排序方式: 共有690条查询结果,搜索用时 0 毫秒
681.
682.
Nicolas P Mäder U Dervyn E Rochat T Leduc A Pigeonneau N Bidnenko E Marchadier E Hoebeke M Aymerich S Becher D Bisicchia P Botella E Delumeau O Doherty G Denham EL Fogg MJ Fromion V Goelzer A Hansen A Härtig E Harwood CR Homuth G Jarmer H Jules M Klipp E Le Chat L Lecointe F Lewis P Liebermeister W March A Mars RA Nannapaneni P Noone D Pohl S Rinn B Rügheimer F Sappa PK Samson F Schaffer M Schwikowski B Steil L Stülke J Wiegert T Devine KM Wilkinson AJ van Dijl JM Hecker M Völker U Bessières P 《Science (New York, N.Y.)》2012,335(6072):1103-1106
683.
Manon Vincent Queju Tong Nasko Terziev Geoffrey Daniel Cecilia Bustos William Gacitúa Escobar Isabelle Duchesne 《Wood Science and Technology》2014,48(1):7-22
Nanoindentation is a powerful tool for hardness testing on a very small scale. Since the technique was first introduced for studying wood cell wall mechanics, it has been integrated as an important tool for measuring the modulus of elasticity and hardness of wood cell walls. In this study, hardness measured with nanoindentation (nanohardness) was compared with hardness measured by the standard Brinell test method (Brinell hardness) on jack pine (Pinus banksiana Lamb.) wood. Nanoindentation was performed on both the S2 layer of the secondary cell wall and the middle lamella (ML) of early- and latewood fibers. Four annual growth rings were studied. The influence of growth ring and initial spacing on both measurements was analyzed. The relationship between Brinell hardness, nanoindentation measurements, and average ring density was also studied. Results suggest that Brinell- and nanohardness are controlled by different mechanisms and factors. The location of nanohardness measurements (i.e., S2 layer or ML) also influenced hardness differently. It was concluded that nanomeasurements are not an exact representation of wood mechanical properties conducted at the macro level because of the hierarchical structure of wood. The effect of other factors such as moisture or wood extractive content may also need consideration. 相似文献
684.
Jacques V Wu E Grosshans F Treussart F Grangier P Aspect A Roch JF 《Science (New York, N.Y.)》2007,315(5814):966-968
Wave-particle duality is strikingly illustrated by Wheeler's delayed-choice gedanken experiment, where the configuration of a two-path interferometer is chosen after a single-photon pulse has entered it: Either the interferometer is closed (that is, the two paths are recombined) and the interference is observed, or the interferometer remains open and the path followed by the photon is measured. We report an almost ideal realization of that gedanken experiment with single photons allowing unambiguous which-way measurements. The choice between open and closed configurations, made by a quantum random number generator, is relativistically separated from the entry of the photon into the interferometer. 相似文献
685.
686.
Detection of the presence of hazelnut oil in olive oil by FT-raman and FT-MIR spectroscopy 总被引:4,自引:0,他引:4
Baeten V Fernández Pierna JA Dardenne P Meurens M García-González DL Aparicio-Ruiz R 《Journal of agricultural and food chemistry》2005,53(16):6201-6206
The detection of the presence of refined hazelnut oil in refined olive oil at low percentages is still a challenge with the current official standards. FT-Raman and FT-MIR spectroscopies have been used to determine the level of detection of the presence of hazelnut oil in olive oil. Spectroscopic analysis has been made not only with the entire oil but also with its unsaponifiable matter. Univariate and multivariate statistical models have been designed with this objective. This study shows that a complete discrimination between olive and hazelnut oils is possible and that adulteration can be detected if the presence of hazelnut oil in olive oil is >8% and if the blends are of Turkish olive and hazelnut oils. The limit of detection is higher when the blends are of edible oils from diverse geographical origins. 相似文献
687.
Varlet V Knockaert C Prost C Serot T 《Journal of agricultural and food chemistry》2006,54(9):3391-3401
The odorant volatile compounds of raw salmon and smoked salmon have been investigated by two gas chromatography-olfactometry methods (frequency detection and odorant intensity) and gas chromatography-mass spectrometry. After simultaneous steam distillation-solvent extraction with diethyl ether and the recovery of the aromatic extract in ethanol, qualitative olfactometric characterization and identification followed by a quantitative assessment of the odorant volatile compounds were carried out. The origin of many odorant compounds of smoked salmon can be attributed to wood smoke. Another part of smoked salmon aroma is due either to the odorant compounds of the raw fish flesh or to an evolution of fish flesh aroma thanks to the smoking process conditions. Forty-nine odorant compounds have been identified in fresh salmon and 74 in smoked salmon. Carbonyl compounds, such as heptanal or (E,Z)-2,6-nonadienal, show a high detection frequency and odorant intensity in unsmoked fish, giving the flesh its typical fishy odor. For smoked salmon, phenolic compounds, such as cresol or guaiacol, and furanic compounds seem to be responsible for the smoked odor. 相似文献
688.
Global patterns of influenza a virus in wild birds 总被引:1,自引:0,他引:1
Olsen B Munster VJ Wallensten A Waldenström J Osterhaus AD Fouchier RA 《Science (New York, N.Y.)》2006,312(5772):384-388
The outbreak of highly pathogenic avian influenza of the H5N1 subtype in Asia, which has subsequently spread to Russia, the Middle East, Europe, and Africa, has put increased focus on the role of wild birds in the persistence of influenza viruses. The ecology, epidemiology, genetics, and evolution of pathogens cannot be fully understood without taking into account the ecology of their hosts. Here, we review our current knowledge on global patterns of influenza virus infections in wild birds, discuss these patterns in the context of host ecology and in particular birds' behavior, and identify some important gaps in our current knowledge. 相似文献
689.
Jay R. Rooker David H. Secor Vincent S. Zdanowicz Gregorio De Metrio Lidia Orsi Relini 《Fisheries Oceanography》2003,12(2):75-84
Chemical signatures in the otoliths of teleost fishes represent natural tags that may reflect differences in the chemical and physical characteristics of an individuals' environment. Otolith chemistry of Atlantic bluefin tuna (Thunnus thynnus) was quantified to assess the feasibility of using these natural tags to discriminate juveniles (age 0 and age 1) from putative nurseries. A suite of six elements (Li, Mg, Ca, Mn, Sr and Ba) was measured in whole otoliths using solution‐based inductively coupled plasma mass spectrometry. Otolith chemistry of age‐1 T. thynnus collected from the two primary nurseries in the Mediterranean Sea and western Atlantic Ocean differed significantly, with a cross‐validated classification accuracy of 85%. Spatial and temporal variation in otolith chemistry was evaluated for age‐0 T. thynnus collected from three nurseries within the Mediterranean Sea: Alboran Sea (Spain), Ligurian Sea (northern Italy), and Tyrrhenian Sea (southern Italy). Distinct differences in otolith chemistry were detected among Mediterranean nurseries and classification accuracies ranged from 62 to 80%. Interannual trends in otolith chemistry were observed between year classes of age‐0 T. thynnus in the Alboran Sea; however, no differences were detected between year classes in the Tyrrhenian Sea. Age‐0 and age‐1 T. thynnus collected from the same region (Ligurian Sea) were also compared and distinct differences in otolith chemistry were observed, indicating ontogenetic shifts in habitat or elemental discrimination. Findings suggest that otolith chemistry of juvenile T. thynnus from different nurseries are distinct and chemical signatures show some degree of temporal persistence, indicating the technique has considerable potential for use in future assessments of population connectivity and stock structure of T. thynnus. 相似文献
690.
Christian Spalthoff Vincent L. Salgado Narayanan Balu Michael D. David Philip Hehlert Huazhang Huang John E. Jones Ramani Kandasamy Gabriel A. Knudsen Katherine R. Lelito James B. Machamer Alexandre Nesterov Michael Tomalski Gregory D. Wahl Barbara J. Wedel Martin C. Göpfert 《Pest management science》2023,79(5):1635-1649
The cover image is based on the Research Article The novel pyridazine pyrazolecarboxamide insecticide dimpropyridaz inhibits chordotonal organ function upstream of TRPV channels by Christian Spalthoff et al., https://doi.org/10.1002/ps.7352