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991.
Evaluating the biodegradation of aromatic hydrocarbons by monitoring of several functional genes 总被引:1,自引:0,他引:1
Various microbial activities determine the effectiveness of bioremediation processes. In this work, we evaluated the feasibility
of gene array hybridization for monitoring the efficiency of biodegradation processes. Biodegradation of 14C-labelled naphthalene and toluene by the aromatic hydrocarbon-degrading Pseudomonas putida F1, P. putida mt-2 and P. putida G7 was followed in mixed liquid culture microcosm by a preliminary, nylon membrane-based gene array. In the beginning of
the study, toluene was degraded rapidly and increased amount of toluene degradation genes was detected by the preliminary
gene array developed for the study. After toluene was degraded, naphthalene mineralization started and the amount of naphthalene
degradation genes increased as biodegradation proceeded. The amount of toluene degradation genes decreased towards the end
of the study. The hybridization signal intensities determined by preliminary gene array were in good agreement with mineralization
of naphthalene and toluene and with the amount of naphthalene dioxygenase and toluene dioxygenase genes quantified by dot
blot hybridization. The clear correlation between the results obtained by the preliminary array and the biodegradation process
suggests that gene array methods can be considered as a promising tool for monitoring the efficiency of biodegradation processes. 相似文献
992.
I. Zimmer E. Usleber H. Klaffke R. Weber P. Majerus H. Otteneder M. Gareis R. Dietrich E. Märtlbauer 《Mycotoxin Research》2008,24(1):40-52
In order to calculate the dietary fumonisin intake of the German consumer, a large survey was carried out on a variety of
potentially contaminated products in the period between December 1998 and July 2001. A total of 1960 food samples comprising
all known relevant groups of products were analysed for fumonisins. Furthermore, 272 of these samples were also analysed for
hydrolysed fumonisins (HFB). For routine analysis enzyme immunoassay was used, confirmatory and control analyses were performed
using HPLC-FLD after precolumn derivatisation, or by LC-MS/MS. Daily intake of fumonisins was calculated by combining fumonisin
contamination data obtained in this study with available food consumption data for Germany. In a “mean case” scenario, median
fumonisin levels in foods and mean food intake values were used. To generate a “bad case” scenario, the 90th percentile of fumonisin levels in foods and mean food intake values were combined. The overall daily fumonisin intake by
the German consumer was 1.1 μg in the “mean case” scenario, and 21 μg in the “bad case” scenario. It was concluded that in
general there is no increased risk for the German consumer in aspects of exceeding the recommended tolerable daily intake
of fumonisins (2 μg/kg body weight). However, certain products (and certain brands of products) were repeatedly found to contain
elevated fumonisin levels, which in a “worst case” scenario (“high” food intake of maize-based products) could pose a potential
risk for the consumer, in particular concerning foods for infants and young children. High fumonisin levels were found in
infant foods in 1999, but contamination levels decreased strongly in the following years. HFBs (mostly HFB1) were frequently found in processed cereals such as corn flakes, but in relatively low concentrations. According to our findings,
the new European Union maximum levels for fumonisins are suitable to eliminate peak contamination levels of fumonisins in
foods, but would lead to a regular excess of the TDI for infants and young children if these maximum levels would indeed be
exhausted.
Financial support: This work was financially supported by the German Federal Ministry for Nutrition, Agriculture and Consumer
Protection, research grant 415-6080-1/60 (BMG alt). 相似文献
993.
The heat-driven phenology model used for initiating codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), management in Washington state was examined to determine the need for using the capture of the first moth as a method of synchronizing the model and phenology of field populations (= biofix). We examined trap catch data taken at 1-2-d intervals from two research orchards; one data set encompassed a 28-yr period and the other data set a 4-yr period. We also examined consultant-collected data taken at 7-10-d intervals from 15 sites (N = 81), mostly between 2001 and 2005. At the two research sites, we found the mean biofix occurred at 96 degree-days (DD) (DD Celsius by using 10 degrees C lower threshold and 31.1 degrees C horizontal upper threshold) after 1 January (SD = 14.4; min. = 68, max = 122). After correcting for longer sampling intervals in the consultant data set, the biofix at the nonresearch sites occurred at 97 DD (N = 50, SD = 14.4; min. = 74, max = 120), nearly identical to that at the research sites. We also examined the performance of the codling moth model at predicting moth flight and egg hatch using a biofix and by just accumulating heat units from 1 January. The model performance was similar in both generations regardless of whether a biofix was used. The elimination of biofix simplifies management and eliminates mistakes associated with poor trap catch, particularly in low-pressure situations where mating disruption reduces trap efficiency. 相似文献
994.
A subclass of proteins with the SEA (sea urchin sperm protein, enterokinase, and agrin) domain fold exists as heterodimers generated by autoproteolytic cleavage within a characteristic G− 1S+ 1VVV sequence. Autoproteolysis occurs by a nucleophilic attack of the serine hydroxyl on the vicinal glycine carbonyl followed by an N → O acyl shift and hydrolysis of the resulting ester. The reaction has been suggested to be accelerated by the straining of the scissile peptide bond upon protein folding. In an accompanying article, we report the mechanism; in this article, we provide further key evidence and account for the energetics of coupled protein folding and autoproteolysis. Cleavage of the GPR116 domain and that of the MUC1 SEA domain occur with half-life (t½) values of 12 and 18 min, respectively, with lowering of the free energy of the activation barrier by ∼ 10 kcal mol− 1 compared with uncatalyzed hydrolysis. The free energies of unfolding of the GPR116 and MUC1 SEA domains were measured to ∼ 11 and ∼ 15 kcal mol− 1, respectively, but ∼ 7 kcal mol− 1 of conformational energy is partitioned as strain over the scissile peptide bond in the precursor to catalyze autoproteolysis by substrate destabilization. A straining energy of ∼ 7 kcal mol− 1 was measured by using both a pre-equilibrium model to analyze stability and cleavage kinetics data obtained with the GPR116 SEA domain destabilized by core mutations or urea addition, as well as the difference in thermodynamic stabilities of the MUC1 SEA precursor mutant S1098A (with a G− 1A+ 1VVV motif) and the wild-type protein. The results imply that cleavage by N → O acyl shift alone would proceed with a t½ of ∼ 2.3 years, which is too slow to be biochemically effective. A subsequent review of structural data on other self-cleaving proteins suggests that conformational strain of the scissile peptide bond may be a common mechanism of autoproteolysis. 相似文献
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998.
Bo Fernholm Michael Norén Sven O. Kullander Andrea M. Quattrini Vincent Zintzen Clive D. Roberts Hin‐Kiu Mok Chien‐Hsien Kuo 《Journal of Zoological Systematics and Evolutionary Research》2013,51(4):296-307
A recent phylogenetic analysis of the Myxinidae based on the 16S rRNA gene resulted in synonymization of Paramyxine with Eptatretus. This created homonymy of Paramyxine fernholmi with Eptatretus fernholmi and Paramyxine wisneri with Eptatretus wisneri. In order to resolve this nomenclatural dilemma, we made a more extensive phylogenetic assessment of the Myxinidae and examined the nomenclature of the family. We used 75 sequences (37 of which new for this study) of a 561 bp fragment of the 16S rRNA gene, representing 33 species, and 72 sequences (37 of which new for this study) of a 687 bp fragment of the cytochrome c oxidase subunit I (COI) gene, representing 23 species, to reconstruct the phylogeny of Myxinidae. The monophyly of the subfamily Myxininae, traditionally characterized by having a single pair of external gill openings, was rejected (0.50 Bayesian posterior probability) by the 16S analysis, but supported by the COI and combined COI+16S analyses (0.99 and 0.81 Bpp, respectively). The monophyly of the subfamily Eptatretinae, characterized by having several pairs of external gill openings, was not supported by the 16S analysis and rejected by the COI and combined COI+16S analysis due to the placement of Eptatretus lopheliae as the earliest branch of Myxinidae (0.71 and 0.57 Bpp, respectively). Eptatretus lopheliae and Eptatretus rubicundus formed a monophyletic group and were allocated to a new genus, Rubicundus, characterized by the presence of an elongated tubular nostril and reddish coloration. A new monotypic subfamily, Rubicundinae, was proposed for Rubicundus. The synonymy of the genera Paramyxine and Quadratus with Eptatretus was confirmed. E. fernholmi is renamed Eptatretus luzonicus. Eptatretus wisneri was renamed Eptatretus bobwisneri. Petromyzon cirrhatus Forster, 1801, Homea banksii Fleming, 1822, and Bdellostoma forsteri Müller, 1836 are synonyms, but no type specimens are known to exist. Petromyzon cirrhatus was designated as type species of Eptatretus, conserving present usage. Gastrobranchus dombeyi Shaw, 1804 has priority over other names for Chilean myxinids. Bdellostoma stoutii was designated as type species of Polistotrema Gill. The validity of the Western Atlantic Myxine limosa as distinct from the Eastern Atlantic Myxine glutinosa was confirmed. 相似文献
999.
Meritxell Genovart Jean-Claude Thibault José Manuel Igual Maria del Mar Bauzà-Ribot Corinne Rabouam Vincent Bretagnolle 《PloS one》2013,8(8)
Dispersal is critically linked to the demographic and evolutionary trajectories of populations, but in most seabird species it may be difficult to estimate. Using molecular tools, we explored population structure and the spatial dispersal pattern of a highly pelagic but philopatric seabird, the Cory''s shearwater Calonectris diomedea. Microsatellite fragments were analysed from samples collected across almost the entire breeding range of the species. To help disentangle the taxonomic status of the two subspecies described, the Atlantic form C. d. borealis and the Mediterranean form C. d. diomedea, we analysed genetic divergence between subspecies and quantified both historical and recent migration rates between the Mediterranean and Atlantic basins. We also searched for evidence of isolation by distance (IBD) and addressed spatial patterns of gene flow. We found a low genetic structure in the Mediterranean basin. Conversely, strong genetic differentiation appeared in the Atlantic basin. Even if the species was mostly philopatric (97%), results suggest recent dispersal between basins, especially from the Atlantic to the Mediterranean (aprox. 10% of migrants/generation across the last two generations). Long-term gene flow analyses also suggested an historical exchange between basins (about 70 breeders/generation). Spatial analysis of genetic variation indicates that distance is not the main factor in shaping genetic structure in this species. Given our results we recommend gathering more data before concluded whether these taxa should be treated as two species or subspecies. 相似文献
1000.
Ilse J. E. Flink Rick G. Prins Johan J. P. Mackenbach Vincent W. Jaddoe Albert Hofman Frank C. Verhulst Henning Tiemeier Hein Raat 《PloS one》2013,8(8)