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331.
The prevalence of health problems and malnutrition in Bolivia is exceptionally high, even in comparison to other underdeveloped countries. This study analyzes the relationship between a two measures of child health--height-for-age and weight-for-age z-scores--and a set of physical and cultural determinants of child nutrition, including mother's characteristics, household assets and access to public services. The ultimate aim is to identify the most important determinants of child health and to measure the relative impact of each factor on the height and weight z-scores. A sequential strategy was adopted in order to estimate a two-equation linear model with correlated error terms. A major finding points to geographical and cultural variables as main causes of nutritional status and highlights the role of mother's anthropometrical characteristics. This study uses data on over 3000 children gathered from a Demographic and Health Survey (DHS). 相似文献
332.
Minoru Murai 《Population Ecology》1974,16(1):112-126
Summary The greasy cut worm,Agrotis ypsilon
Rott., has a characteristic habit; the larva feeds on the small seedling of the host plant. Studies in a population in outbreak
area suggested that the food shortage temporally took place, causing the reduction of weights of pupae and adults. The fact
that this species depends on the small seedling as the host seemed to be responsible for this food shortage. However, it was
found that the larval crowding also affected the body weight, even if the food was supplied in excess. It was further suggested
that the weight reduction is due to the injury caused by the encounter of larvae.
The oviposition habit to lay small egg masses and the aggressive behaviour of the larva was considered to be responsible for
the uniform distribution at the later larval stage. Probably, the larval dispersion enabled the larva to forage in the most
effective way as well as it protected the larva from the attack of another ones. As a result, this would enable the maximum
number of individuals to survive. It seemed that the functions noted above did not work in the population being under outbreak
condition, because the larval density was unusually high due to mass-invasion of moths. 相似文献
333.
The effects of alkali type and the concentration in the alkali treatments on the weight loss in six cellulosic fibers and their influences on the fibrillation tendency were investigated. The fibril number of the cellulosic fibers pretreated with alkalis (FNpre) increased with increasing the alkali concentrations as well as the weight loss of the fiber except in the lyocell fiber treated in NaOH and KOH solutions. The FNpre in lyocell was reduced as the fibers were treated in 5 mol/l NaOH and KOH solutions. This result and the fact that the fibers were split in organic alkali such as tetramethylammonium hydroxide even at the low weight loss suggested that not only the loss of cellulose component but also reorganization of microfibril structure, inhomogeneous swelling of the fibers and other influences control the fibrillation tendency of cellulosic fibers. 相似文献
334.
Michele Ver Ploeg Lisa Mancino Biing-Hwan Lin Chia-Yih Wang 《Economics & Human Biology》2007,5(1):20-36
High rates of obesity among low-income populations have led some to question whether USDA's food assistance programs have contributed to this health problem. Using data from National Health and Nutrition Examination Surveys (NHANES), this study shows that the association between food assistance program participation and body weight measures has weakened over the past three decades. Earlier NHANES data show that program participants were more likely to be overweight than individuals who were eligible but not participating in the program. This was particularly true among white women. However, the more recent data show that these differences have vanished, as the BMI of the rest of the population has caught up to BMI levels of food stamps recipients. 相似文献
335.
Minoru Murai 《Population Ecology》1975,16(2):289-308
A model was made to clarify the basic processes of competition to occur among larvae by the exploitation as defined byBakker (1969). It was found that this model is applicable to the experimental results on the food exploitation among Droshophila larvae obtained byBakker (1961). In the model the preimaginal stage is divided into two periods;Tf which is the time that a group of larvae spends in exhausting the food after hatching, and Ts which is the duration of the starvation period after Tf.Tf and then Wl (larval body weight) just after the end of Tf are decided by Fs (amount of food supplied per larva at larval hatching) and Fc (amount of food consumed per larva).Tf affects on the onset of Ts as well as Rl (rate of decrease in the individual body weight during Ts).Wa (weight of emerging adults) is gotten by a subtraction of Rl from Wl just after the end of Tf,Re is affected directly by these components of Wl and Rl. As a result, Wa and Re are expressed by functions of Fs. This model confirmed that the food exploitation lead to the competition of scramble type. Finally it was suggested that there exist some strategies which prevent ill-effects owing to the food exploitation. 相似文献
336.
Different population categories of apterous green peach aphid, adult sweet potato weevils, mature Caribbean fruit fly larvae and tobacco budworm larvae were permitted to move on dispersion ranges in the laboratory. Determination of distances dispersed by the larvae were made to show the effects of population sizes. In general, longer distances were dispersed by more individuals when larger numbers were released as compared with smaller ones. 相似文献
337.
《Endocrinología y nutrición》2014,61(5):264-273
Few effective therapeutic tools are currently available to fight the increasing prevalence of obesity and its associated comorbidities. Bariatric surgery is the only treatment with proven long-term effectiveness, but is associated to a high surgical risk and significant economic costs because of its technical complexity and the characteristics of patients. This is leading to development of new endoscopic procedures with less clinical risks and economic costs, while maintaining the benefits in terms of morbidity and mortality, which could even serve as a bridging element before surgery in cases where this is unavoidable, allowing for preoperative weight loss and control of comorbidities in order to improve anesthetic risks and possible complications. The purpose of this review was to analyze the most relevant and promising endoscopic techniques currently available. 相似文献
338.
A variety of characteristics were studied in populations of the onion root maggot, Hylemya antiqua, to determine the extent to which the age of the female producing a batch of eggs might affect heterogeneity in her offspring. Early-born offspring were found to be reproductively most successful. They had the longest mean expectation of life, a relatively low mortality rate into mid-life, the highest average fecundity, the highest mean rate of egg production, and they produced the highest percentage of female offspring. On the other hand, mid-born offspring were hardiest. They also had a long mean expectation of life, comparable to that for early-born offspring but, in addition, they had the lowest sustained mortality rate and the greatest ability to survive food stress. Their robustness may have been acquired at the expense of certain reproductive capabilities however, in that their average fecundity was lower than their early-born siblings', and their rate of egg production was more variable. Late-born offspring were the most mortality-prone and the least fecund, but they had the shortest mean generation time. These differences must be evaluated in terms of their effects on the rate of natural increase and on population growth. Maternal age was found to influence pupal size, although the provenance groups differed significantly from each other and, in fact, showed opposite trends within their respective cohort groups. Size itself, and the ability of a species to alter the size at which it pupates, may be characteristics which have evolved to fit a specific set of environmental conditions. 相似文献
339.
Paul C. Dechow 《American journal of physical anthropology》1983,60(1):113-123
Body weights of adult baboons (genera Papio, Mandrillus, and Theropithecus) were gathered from notes of collectors and museum records. However, these data were insufficient to establish mean body weights for all baboon groups. Thus, log cube roots of mean body weights were regressed as functions of the logs of several cranial and dental variables. The resulting least squares regression coefficients were used to estimate weights for 503 adult baboons from cranial measurements. The ability of the various regression functions to assess baboon body weight was determined by comparing reported and estimated mean and individual body weights. The best estimator of baboon body weights was the function derived from the factor scores of a principal components analysis of seven craniometric variables regressed on body weight. However, each of these craniometric variables singly was nearly as precise an estimator of body weight as the multivariate combination of all seven. Other measurements such as dental dimensions and foramen magnum area estimated weight less accurately. Body weight estimates derived from the regression analyses coupled with museum and literature records allowed an assessment of size relationships among all baboon groups. 相似文献