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471.
Abdul G Lone Vincent Deslandes John HE Nash Mario Jacques Janet I MacInnes 《BMC microbiology》2009,9(1):195
Background
Actinobacillus pleuropneumoniae causes contagious pleuropneumonia, an economically important disease of commercially reared pigs throughout the world. To cause this disease, A. pleuropneumoniae must rapidly overcome porcine pulmonary innate immune defenses. Since bronchoalveolar fluid (BALF) contains many of the innate immune and other components found in the lungs, we examined the gene expression of a virulent serovar 1 strain of A. pleuropneumoniae after exposure to concentrated BALF for 30 min. 相似文献472.
Lone Aagesen Claudia A. Szumik Fernando O. Zuloaga Osvaldo Morrone 《Cladistics : the international journal of the Willi Hennig Society》2009,25(3):295-310
The distribution data of 340 grass species sampled in a region of 53.219 km2 in the northwestern corner of Argentina (between ∼21°S and ∼24°S) were analyzed to search for concordance in species distributions by using the program NDM/VNDM. Here, the traditional biogeographic hypothesis proposed for the region is evaluated for the first time by using a quantitative method and an optimal criterion specifically developed within the context of areas of endemism. Three different grid sizes (0.5° × 0.5°, 0.35° × 0.35 ° and 0.2° × 0.2°) were used to analyze three nested data sets: species found in the Andes of Argentina, Bolivia and/or Chile; Andean distributed species; and all grass species found in the study region. The main areas supported by the analyses correspond generally to the traditional biogeographic hypothesis proposed for the region. Local distribution patterns defined by species restricted to the study region were best supported under the small grid sizes, while the bigger grid sizes recovered areas defined by species with a broader distribution. The local distribution patterns emerged in all the analyses even when widespread species were added to the data set.
© The Willi Hennig Society 2009. 相似文献
© The Willi Hennig Society 2009. 相似文献
473.
Effects of hypolimnetic oxygenation on water quality: results from five Danish lakes 总被引:1,自引:0,他引:1
Lone Liboriussen Martin Søndergaard Erik Jeppesen Inge Thorsgaard Simon Grünfeld Tue S. Jakobsen Kim Hansen 《Hydrobiologia》2009,625(1):157-172
Stratified eutrophic lakes often suffer from hypolimnetic oxygen depletion during summer. This may lead to low redox conditions
and accumulation of phosphate and ammonia in the hypolimnion. Hypolimnetic oxygenation has been used as a lake management
strategy to improve the water quality in five eutrophic dimictic Danish lakes where oxygenation was conducted for 4–20 years.
In one lake, the hypolimnetic oxygen concentration clearly improved by oxygenation, whereas the other four lakes still exhibited
low mean summer levels (<2.2 mg O2 l−1). Oxygenation generally increased the hypolimnetic water temperature by 0.5–2°C, but in one lake it increased by 4–6°C. In
all lakes, oxygenation significantly reduced the hypolimnetic concentrations of phosphorus and ammonia during stratification.
The accumulation of phosphorus and ammonia typically decreased by 40–88%. In two lakes oxygenation was stopped for 1–2 years
and here hypolimnion concentrations of both phosphorus and ammonia increased again. Surface water quality only improved in
one lake, but was likely also influenced by simultaneously occurring changes in external nutrient loading. Overall, it is
concluded that hypolimnetic oxygenation reduces the hypolimnetic accumulation of phosphorus and ammonia and may prevent anoxia
in the deeper parts of the lake. However, long-term oxygenation is required and it is uncertain whether the overall lake water
quality can be improved by oxygenation. Reduction of the external nutrient loading is still essential to improve lake water
quality.
Handling editor: Luigi Naselli-Flores 相似文献
474.
Helga M. Ögmundsdóttir Ingibjörg Pétursdóttir Ingibjörg Gudmundsdóttir Laufey Ámundadóttir Lone Rønnov-Jessen Ole W. Petersen 《In vitro cellular & developmental biology. Animal》1993,29(12):936-942
Summary Breast carcinomas commonly contain varying amounts of fibrous stroma and infiltrates of lymphoid cells. Dickson and Lippman
(Endocrine Rev., 8,29, 1987) have proposed a model of growth regulation in breast cancer involving interactions between stroma
and carcinoma cells. This model is based on results obtained with established cell lines. In an effort to bring experimentation
closer to the clinical situation we have used short-term primary cultures from human breast cancer in co-cultures with lymphocytes
and fibroblasts. Cultures were established in a chemically defined serum-free medium (CDM3). Cell types were characterized
on the basis of live morphology and expression of vimentin and keratin 18. A semi-quantitative system was developed for measuring
growth of epithelial cells, thus defining two indices: maximal growth index (GI-max) and growth rate (GR). Moderate-to-good
growth was obtained from 34 out of 46 carcinoma samples (74%) and 30 out of 38 parallel samples of non-cancerous tissue (79%).
Success in culture was negatively correlated with the amount of hard stroma but unrelated to age of patient or clinical status.
Malignant epithelium was clearly identified in 12 out of 34 (35%) carcinoma samples. For the evaluation of responses of epithelial
cells in co-cultures, the cultures from each sample were ranked according to GI-max. From 20 co-culture experiments using
carcinoma samples, the following results were obtained: the highest GI-max was found in 11 of the co-cultures with lymphocytes;
in six of the co-cultures with fibroblasts; in one case in the control culture without partner cells; and in two experiments
there was no difference between controls and co-cultures. The corresponding values for non-cancerous samples were: 5 out of
17, 2/17, 2/17, and 8/17. Control experiments performed without partner cells confirmed that these differences in GI-max between
cultures were beyond random variations. Four samples displayed particularly vigorous responses to lymphocytes, and two samples
responded extensively to fibroblasts. In four of these six samples cancer cells proliferated. We conclude that it is feasible
to use primary cultures of breast carcinomas for experimentation. Fibroblasts did not have very marked effects on epithelial
cell growth, but, contrary to expectation, there was a clear tendency for lymphocytes to stimulate growth. 相似文献
475.
Background
In insects, circadian clocks play a key role in enhancing fitness by regulating life history traits such as developmental time and adult lifespan. These clocks use environmental light/dark (LD) cycles to fine-tune a wide range of behavioral and physiological processes. To study the effect of environmental LD conditions on pre-adult fitness components, we used two dark-dwelling sympatric species of ants (the night active Camponotus compressus and the day active Camponotus paria), which normally develop underground and have fairly long pre-adult developmental time. 相似文献476.
Ewa Rajpert-De Meyts Christina E. Hoei-Hansen Anne Marie Ottesen Lone Frydelund-Larsen Mette Holm Niels E. Skakkebaek 《Andrologie》2002,12(3):262-268
The incidence of testicular germ cell cancer has been increasing over recent decades in many countries of the world. Many studies over recent years have reported adverse trends in other aspects of male reproductive health, such as high and possibly increasing frequencies of undescended testis and hypospadias, declining semen quality, and an apparently growing demand for assisted reproduction due to male infertility. This article summarises the available evidence supporting a new concept that these male reproductive abnormalities may be signs of a single underlying entity: testicular dysgenesis syndrome (TDS). This syndrome, caused by nonspecific delays and aberrations of early testicular development, may be increasingly common because of deteriorating environmental and life-style factors that impair gonadal development. Geographical and ethnic differences in the incidence of various forms of TDS could be explained either by differences in exposure to adverse factors or by differences in genetic susceptibility to these factors. 相似文献