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991.
992.
Timothy H Rainer Peter A Cameron DeVilliers Smit Kim L Ong Alex Ng Wing Hung David Chan Po Nin Anil T Ahuja Louis Chan Yik Si Joseph J Y Sung 《BMJ (Clinical research ed.)》2003,326(7403):1354-1358
Objectives To determine the clinical and radiological features of
severe acute respiratory syndrome (SARS) and to evaluate the accuracy of the
World Health Organization''s guidelines on defining cases of SARS.Design Prospective observational study.Setting A newly set up SARS screening clinic in the emergency
department of a university hospital in Hong Kong''s New Territories.Participants 556 hospital staff, patients, and relatives who
attended the screening clinic and who had had contact with someone with
SARS.Main outcome measure Number of confirmed cases of SARS.Results Of the 556 people, 141 were admitted to hospital, and 97 had
confirmed SARS. Fever, chills, malaise, myalgia, rigor, loss of appetite,
vomiting, diarrhoea, and neck pain but not respiratory tract symptoms were
significantly more common among the 97 patients than among the other patients.
The overall accuracy of the WHO guidelines for identifying suspected SARS was
83% and their negative predictive value was 86% (95% confidence interval 83%
to 89%). They had a sensitivity of 26% (17% to 36%) and a specificity of 96%
(93% to 97%).Conclusions Current WHO guidelines for diagnosing suspected SARS may
not be sufficiently sensitive in assessing patients before admission to
hospital. Daily follow up, evaluation of non-respiratory, systemic symptoms,
and chest radiography would be better screening tools. 相似文献
993.
994.
Coregonine fishes are notorious taxonomicproblems due to their extreme morphological andecological variation. In North America, diversity is particularly baffling among ciscoes, and both morphological and phylogenetic analyses have resulted in major polytomy among the 8 taxa of the ``Coregonus artedi' species complex. Ciscoes arealso a devastated group, accounting for 10% ofthe fish species listed by the Committee on theStatus of Endangered Wildlife in Canada. Here,we complete the genetic characterization ofNorth American ciscoes with mitochondrial andmicrosatellites markers previously used toanalyse populations of C. artedi in orderto elucidate the evolutionary history andidentify appropriate conservation units. Ourresults revealed a complex evolutionary historymarked by postglacial reticulation eventscoupled with recent and independent evolutionof similar phenotypes (taxa). Genetic variationreflects geography rather than taxonomy, andconsequently, we recommend that a single taxon,C. artedi (sensu lato) be recognized.Local genetic differentiation is often coupledwith ecophenotypic diversification, and gillraker polymorphisms, depth-related habitatpreference and reproductive behaviour areconsidered as phenotypic traits with probableadaptive value contributing to the nicheexpansion of ciscoes. Ecomorphotypes of eachparticular locale thus represent a uniqueexpression of a diverse genetic pool stillundergoing divergence and sorting.Consequently, ciscoes from lakes with distinctecomorphotypes are recognized as ESUs, as wellas each of sympatric forms when they aregenetically differentiated. We recommend thatan ESU strategy focusing at a very local levelbe adopted for continental ciscoes as a validalternative to protect significant evolutionaryprocesses of divergence encountered inpolytypic species of newly colonized habitats. 相似文献
995.
GIT1-like proteins are GTPase-activating proteins (GAPs) for Arfs and interact with a variety of signaling molecules to function as integrators of pathways controlling cytoskeletal organization and cell motility. In this report, we describe the characterization of a Drosophila homologue of GIT1, dGIT, and show that it is required for proper muscle morphogenesis and myotube guidance in the fly embryo. The dGIT protein is concentrated at the termini of growing myotubes and localizes to muscle attachment sites in late stage embryos. dgit mutant embryos show muscle patterning defects and aberrant targeting in subsets of their muscles. dgit mutant muscles fail to localize the p21-activated kinase, dPak, to their termini. dPak and dGIT form a complex in the presence of dPIX and dpak mutant embryos show similar muscle morphogenesis and targeting phenotypes to that of dgit. We propose that dGIT and dPak are part of a complex that promotes proper muscle morphogenesis and myotube targeting during embryogenesis. 相似文献
996.
Candida albicans and C. tropicalis obtained from whole saliva of patients presenting signs of oral candidosis were assayed for quantification of colony forming
units, exoenzyme activity (phospholipase and proteinase) and antifungal drug sensitivity (amphotericin B, fluconazole and
itraconazole) by the reference method of the Clinical and Laboratory Standards Institute. The number of colony forming units
per milliliter varied according to the Candida species involved and whether a single or mixed infection was present. Proteinase activity was observed in both C. albicans and C. tropicalis, but phospholipase activity was noted only in C. albicans. In vitro resistance to antifungals was verified in both species, but C. tropicalis appears to be more resistant to the tested antifungals than C. albicans. 相似文献
997.
998.
999.
Patrice Savadogo Mulualem Tigabu Louis Sawadogo Per Christer Odén 《African Journal of Ecology》2009,47(4):699-710
Fire is an integral ecological factor in African savanna ecosystems, but its effects on savanna productivity are highly variable and less understood. We conducted a field experiment to quantify changes in herbaceous phytomass and nutrient composition in a Sudanian savanna woodland subjected to annual early fire from 1993 to 2004. Fire effects were also assessed on two perennial and two annual grass species during the following growing season. Early fire significantly reduced above‐ground phytomass of the studied species (P = 0.03), their crude protein (P = 0.022), neutral detergent insoluble crude protein (P = 0.016) and concentrations of Ca, Fe and Mn (P < 0.05). Perennial grasses had higher above‐ground phytomass but lower total crude protein and fat than annual grasses. Nonstructural carbohydrates tended to be higher for annuals, while fibre and lignin contents were high for perennials. Except Na and Fe, the concentration of mineral elements varied between species. Fire did not affect measures of digestibility and metabolizable energy, but its effect differed significantly among species. In conclusion, the results illustrate that long‐term frequent fire will counterbalance the short‐term increase in soil fertility and plant nutrient concentrations claimed to be accrued from single or less frequent fire. 相似文献
1000.
Starch obtained from yellow and white plantain varieties were subjected to proximate analysis, physicochemical and rheological characterization in order to evaluate their properties. Yellow plantain variety gave higher yield of starch than the white variety. The two varieties differed in the purity of starch extract; white plantain starch contained: ash (1.09%), protein (0.640%) and fat (0.276%) while yellow plantain starch contained: ash (0.95%), protein (0.325%) and fat (0.403%). The amylose content of yellow plantain starch (24.36% (apparent), 26.13% (total)) was similar to that of white plantain starch (24.24% (apparent), 26.01% (total)). Scanning electron microscopy revealed bimodal irregular shaped granules (3.74–7.00 and 10.00–33.00 μm) in white plantain starch and elliptical granules (11.22–41.00 μm) in yellow plantain starch. Both starches differed markedly in their physicochemical properties. Their differences in gelatinization temperature (yellow plantain, 64.99–73.90 °C; white plantain, 68.08–77.15 °C), swelling and solubility patterns, and pasting characteristics indicated that yellow plantain starch had weaker granule architecture compared with white plantain starch. Further evidence of differences in properties was obtained from flow and viscoelastic properties of the starch gels, paste clarity and freeze–thaw stability. 相似文献