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601.
Verónica Crespo-Pérez Olivier Dangles Cristina Ibarra Rodrigo Espinosa Patricio Andino Dean Jacobsen Sophie Cauvy-Fraunié 《Freshwater Biology》2020,65(8):1348-1362
- In many mountainous areas, glaciers feed streams characterised by harsh environmental conditions, such as low water temperature, high turbidity, low channel stability, and high temporal variability in flow. Additionally, in many glacierised catchments, the mixture of streams arising from different water sources (glacier melt, groundwater, rainfall) generates high levels of environmental heterogeneity, which enhance species turnover rates and increase regional diversity.
- Studies from mainly temperate regions have revealed some consistent patterns: a predominance of traits adaptive to harsh environmental conditions and reduced functional diversity with increased glaciality, both strongly related to environmental filtering. Here, we investigated variation in functional structure and diversity between macroinvertebrate communities from 15 stream sites, with different water sources (five glacier-fed, five groundwater-fed, and five mixed source) and level of glacier influence, in a glacierised catchment in the Ecuadorian Andes.
- Our results revealed functional differences between communities inhabiting the different stream types. As found in temperate regions, high levels of glaciality were associated with an increase of small-sized taxa that do not swim but are temporarily attached to or burrow in the substrate, have a flying-adult stage, and feed by collecting–gathering. Similarly, we found a general decrease in functional diversity at sites with higher glacier influence. A null modelling approach suggested that in some of our glacier-fed sites, environmental filtering may be the main driver of community assembly, whereas other mechanisms, mainly regional (such as dispersal), but also local (such as intraspecific competition), may gain importance as glacier influence decreases.
- Assemblage composition in streams in tropical glacierised catchments may be driven by both local and regional processes that generate a gradient of decreasing functional diversity with stronger glacier influence. However, lack of knowledge of relevant traits for taxa in tropical glacierised streams currently poses a substantial obstacle to predicting changes likely to arise from global warming and glacier melt in this region.
602.
Juan Diego Maya Bruce K. Cassels Patricio Iturriaga-Vsquez Jorge Ferreira Mario Faúndez Norbel Galanti Arturo Ferreira Antonio Morello 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2007,146(4):601
Current knowledge of the biochemistry of Trypanosoma cruzi has led to the development of new drugs and the understanding of their mode of action. Some trypanocidal drugs such as nifurtimox and benznidazole act through free radical generation during their metabolism. T. cruzi is very susceptible to the cell damage induced by these metabolites because enzymes scavenging free radicals are absent or have very low activities in the parasite. Another potential target is the biosynthetic pathway of glutathione and trypanothione, the low molecular weight thiol found exclusively in trypanosomatids. These thiols scavenge free radicals and participate in the conjugation and detoxication of numerous drugs. Inhibition of this key pathway could render the parasite much more susceptible to the toxic action of drugs such as nifurtimox and benznidazole without affecting the host significantly. Other drugs such as allopurinol and purine analogs inhibit purine transport in T. cruzi, which cannot synthesize purines de novo. Nitroimidazole derivatives such as itraconazole inhibit sterol metabolism. The parasite's respiratory chain is another potential therapeutic target because of its many differences with the host enzyme complexes. The pharmacological modulation of the host's immune response against T. cruzi infection as a possible chemotherapeutic target is discussed. A large set of chemicals of plant origin and a few animal metabolites active against T. cruzi are enumerated and their likely modes of action are briefly discussed. 相似文献
603.
Guadalupe Valdés Sonia V. González Dania López García Patricio Márquez 《Anthropology & education quarterly》2003,34(1):3-26
In this article we investigate language ideology in a department of Spanish. We are concerned with examining the acquisition and transmission of linguistic culture in departments of foreign languages within university settings and the ways in which views about non-English languages that are part of the American cultural dialogue are maintained and nurtured by educational institutions. Using long-term participant-observation data and focused interviews, we contend that foreign language departments in U.S. colleges and universities, although involved in a nonhegemonic practice—that is, in the teaching of non-English languages—are nevertheless working in concert with deeply held American ideologies about bilingualism and monolingualism. 相似文献
604.
Samuel Zamora Eladio Lin Patricio Domínguez Alonso Rodolfo Gozalo Jos A. Gmez Vintaned 《Annales de Paléontologie》2007,93(4):249-260
A Middle Cambrian edrioasteroid belonging to the genus Cambraster is described from the Middle Cambrian Murero biota (Cadenas Ibéricas, NE Spain). Up to now, this genus was known only from Australia and France. This represents the first record of the class Edrioasteroidea in the Cambrian of Spain. Moreover, preliminary results on the diversity and biostratigraphic position of Cincta, Eocrinoidea and Edrioasteroidea from this area are reported. 相似文献
605.
Seth B Roberts Jennifer L Robichaux Arvind K Chavali Patricio A Manque Vladimir Lee Ana M Lara Jason A Papin Gregory A Buck 《BMC systems biology》2009,3(1):52
Background
Trypanosoma cruzi is a Kinetoplastid parasite of humans and is the cause of Chagas disease, a potentially lethal condition affecting the cardiovascular, gastrointestinal, and nervous systems of the human host. Constraint-based modeling has emerged in the last decade as a useful approach to integrating genomic and other high-throughput data sets with more traditional, experimental data acquired through decades of research and published in the literature. 相似文献606.
B R Concone H Hiss M Del Pilar G Paz C G Patricio W Borzani 《Biotechnology and bioengineering》1972,14(4):609-615
The influence of the following factors on the measurement of yeast concentration in liquid hydrocarbon fermentations was studied: surfactant, type (Tween 20, Tween 80, and G 3300), yeast concentration (0.215 to 0.272 and 3.37 to 4.08 g/liter, as dry matter), oil concentration (8.32 and 61.6 g/liter), surfactant, concentration (0.515, 1.030, 1.545, and 2.060 g/liter), and time of contact of the surfactant with the oil-yeast-aqueous medium mixture (2 and 10 min). The statistical significance of the obtained results was determined. 相似文献
607.
Marcela Hernández Patricio Villalobos Verónica Morgante Myriam González Caroline Reiff Edward Moore & Michael Seeger 《FEMS microbiology letters》2008,286(2):184-190
s -Triazine herbicides are used extensively in South America in agriculture and forestry. In this study, a bacterium designated as strain MHP41, capable of degrading simazine and atrazine, was isolated from agricultural soil in the Quillota valley, central Chile. Strain MHP41 is able to grow in minimal medium, using simazine as the sole nitrogen source. In this medium, the bacterium exhibited a growth rate of μ=0.10 h−1 , yielding a high biomass of 4.2 × 108 CFU mL−1 . Resting cells of strain MHP41 degrade more than 80% of simazine within 60 min. The atzA, atzB, atzC, atzD, atzE and atzF genes encoding the enzymes of the simazine upper and lower pathways were detected in strain MHP41. The motile Gram-negative bacterium was identified as a Pseudomonas sp., based on the Biolog microplate system and comparative sequence analyses of the 16S rRNA gene. Amplified ribosomal DNA restriction analysis allowed the differentiation of strain MHP41 from Pseudomonas sp. ADP. The comparative 16S rRNA gene sequence analyses suggested that strain MHP41 is closely related to Pseudomonas nitroreducens and Pseudomonas multiresinovorans . This is the first s -triazine-degrading bacterium isolated in South America. Strain MHP41 is a potential biocatalyst for the remediation of s -triazine-contaminated environments. 相似文献
608.
Patricio Godoy-Martinez Fabiane G. Nunes Jane Tomimori-Yamashita Milton Urrutia Luis Zaror Victor Silva Olga Fischman 《Mycopathologia》2009,168(3):111-116
Onychomycosis is a fungal infection of the nails with broad aetiological scope, and it represents 18–40% of all onychopathies
and 39% of all superficial mycotic infections. From July 1996 to December 1999, samples of nails were collected from 588 patients
with presumptive diagnosis of onychomycosis at the Dermatology and Mycology Divisions EPM\UNIFESP, Brazil, and the diagnosis
was confirmed in 247 of these cases. The most common pathogens isolated in this study were yeasts in 52% of positive cultures
(Candida albicans 18.3%, Candida parapsilosis 13.8%, other species of Candida 15.4% and other yeasts 4.6%), followed by dermatophytes in 40.6% of positive cultures (the most commonly isolated organisms
were Trichophyton rubrum in 33.2%, followed by Trichophyton mentagrophytes in 6.3% and others 1.2%). Non-dermatophyte moulds were isolated in 7.4% of positive cultures (Fusarium spp. 4.5%, Nattrassia mangiferae 2.3% and Aspergillus spp. 0.6%). Distal and lateral subungual onychomycosis (DLSO) was the commonest clinical pattern 44.6% followed by free edge
onycholysis (FEO) 38.8% and others. In conclusion, this study demonstrated that T. rubrum is the main agent causing onychomycosis in toenails, and species of genus Candida were the main agents isolated in fingernail onychomycosis in our region. 相似文献
609.
Patricio López-Jaramillo Lina P Pradilla Vicente Lahera Federico A Silva Sieger Christian F Rueda-Clausen Gustavo A Márquez 《Trials》2006,7(1):1-12
In ageing men testosterone levels decline, while cognitive function, muscle and bone mass, sexual hair growth, libido and sexual activity decline and the risk of cardiovascular diseases increase. We set up a double-blind, randomized placebo-controlled trial to investigate the effects of testosterone supplementation on functional mobility, quality of life, body composition, cognitive function, vascular function and risk factors, and bone mineral density in older hypogonadal men. We recruited 237 men with serum testosterone levels below 13.7 nmol/L and ages 60–80 years. They were randomized to either four capsules of 40 mg testosterone undecanoate (TU) or placebo daily for 26 weeks. Primary endpoints are functional mobility and quality of life. Secondary endpoints are body composition, cognitive function, aortic stiffness and cardiovascular risk factors and bone mineral density. Effects on prostate, liver and hematological parameters will be studied with respect to safety. Measure of effect will be the difference in change from baseline visit to final visit between TU and placebo. We will study whether the effect of TU differs across subgroups of baseline waist girth (< 100 cm vs. ≥ 100 cm; testosterone level (<12 versus ≥ 12 nmol/L), age (< median versus ≥ median), and level of outcome under study (< median versus ≥ median). At baseline, mean age, BMI and testosterone levels were 67 years, 27 kg/m2 and 10.72 nmol/L, respectively. 相似文献
610.