全文获取类型
收费全文 | 328篇 |
免费 | 10篇 |
专业分类
338篇 |
出版年
2022年 | 5篇 |
2021年 | 4篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 13篇 |
2017年 | 12篇 |
2016年 | 4篇 |
2015年 | 7篇 |
2014年 | 4篇 |
2013年 | 7篇 |
2012年 | 14篇 |
2011年 | 13篇 |
2010年 | 11篇 |
2009年 | 8篇 |
2008年 | 5篇 |
2007年 | 9篇 |
2006年 | 14篇 |
2005年 | 12篇 |
2004年 | 7篇 |
2003年 | 10篇 |
2002年 | 13篇 |
2001年 | 12篇 |
2000年 | 16篇 |
1999年 | 7篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 4篇 |
1992年 | 4篇 |
1991年 | 6篇 |
1990年 | 7篇 |
1989年 | 12篇 |
1988年 | 8篇 |
1987年 | 9篇 |
1986年 | 10篇 |
1985年 | 5篇 |
1984年 | 7篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1976年 | 2篇 |
1975年 | 4篇 |
1974年 | 4篇 |
1973年 | 1篇 |
1972年 | 3篇 |
1971年 | 5篇 |
1970年 | 1篇 |
1969年 | 4篇 |
1968年 | 4篇 |
1966年 | 3篇 |
排序方式: 共有338条查询结果,搜索用时 15 毫秒
31.
Gorbaneva EP Kamchatnikov AG Solopov IN Segizbaeva MO Aleksandrova NP 《Rossi?skii fiziologicheski? zhurnal imeni I.M. Sechenova / Rossi?skaia akademiia nauk》2011,97(1):83-90
Research on studying influence of the rate of muscular training in conditions of additional resistive resistance to breath on a level of physical working capacity, aerobic productivity and a functional condition of system of breath was performed. It is shown, that regular muscular loadings in a combination to resistive resistance to breath in a mode of an interval exposition provide an increase of profitability and efficiency of functioning of breathing system as expressed in increase of expiratory force respiratory muscles, rationalization of parity of volumetric-time parameters of breath pattern that promotes more effective gas exchange and decrease in power cost of respiratory movements and as a result leads to increase in aerobic productivity and growth of the general and special working capacity. At continuous exposition of resistive resistance against a background of muscular training, the increase of inspiratory force of respiratory muscles, increase of functional capacity of system of breath were revealed at physical activity as well as a significant gain of the general physical working capacity. 相似文献
32.
V. V. Isaeva A. V. Akhmadieva Ya. N. Aleksandrova A. I. Shukalyuk A. V. Chernyshev 《Russian Journal of Marine Biology》2011,37(4):303-310
Electron-dense germinal granules, which are usually regarded as markers and key organelles of germline cells, were revealed
in the interstitial (stem) cells of the colonial hydroids Obelia longissima and Ectopleura crocea. The interstitial cells of O. longissima displayed intense alkaline phosphatase activity, a histochemical marker for vertebrate embryonic stem and primary germ cells,
as well as positive reaction to proliferating cell nuclear antigen (PCNA), which is an immunochemical marker for cell reproduction.
Our findings and the literature data suggest the evolutionary conservation and similarity of the morphological and functional
organization of potentially gametogenic stem cells in asexually reproducing invertebrates and germ cells in all studied Metazoa.
The self-renewing pool of such stem cells provides the cellular source for blastogenesis and gametogenesis and the cellular
basis for life functions, including both asexual and sexual reproduction. 相似文献
33.
Katherine ES Lindhe Danny S Meldgaard Per M Jensen Geoffrey A Houser Mette Berendt 《Acta veterinaria Scandinavica》2009,51(1):56
Background
Large regions of central and eastern Europe are recognized as areas where tick-borne encephalitis virus (TBEV) is endemic, including countries neighbouring Denmark. It is therefore timely and relevant to determine if TBEV infections occur in Denmark. This study investigates the presence of antibodies against TBEV in a cross-section of the Danish canine population to assess the level of exposure to TBEV and possibly identify TBEV microfoci in Denmark. 相似文献34.
The preparation conditions for dichlorophosphinylphosphorimidic trichloride were optimized. It was used in the synthesis of esters of imidodiphosphoric acid. The interaction of the trichloride with amines resulted in the corresponding amidodiphosphates rather than in the expected amides of imidodiphosphoric acid. 相似文献
35.
36.
PAULO R. GUIMARES UMBERTO KUBOTA BRUNO ZACARIAS GOMES RAFAEL LUÍS FONSECA CLUDIA BOTTCHER MAURO GALETTI 《Austral ecology》2006,31(1):95-98
Abstract: Red‐rumped agoutis (Dasyprocta leporina) are important seed dispersers/predators of Neotropical large‐seeded plants. Several species of seeds cached by agoutis have an edible reward, in contrast to temperate rodent‐dispersed diaspores. The quick meal hypothesis states that the presence of a reward such as edible pulp will enhance the efficiency of rodents as seed disperses by satiating the animal and, consequently, reducing seed predation and enhancing hoarding. In this study, this hypothesis was tested using as the reference system the pulp and seeds of Hymenaea courbaril. Seeds with and without pulp were offered to agoutis and the behaviour of each individual was recorded. Since the probability of predation and hoarding were complementary, we used the probability of predation. The proportion of agoutis that preyed on at least one seed was similar for seeds with (42.8% of individuals) and without (40.0% of individuals) pulp. In agoutis that preyed upon at least one seed, the probability that they killed a seed did not differ between seeds with (0.17 ± 0.03) and without (0.20 ± 0.08) pulp. Hence, these results do not support the ‘quick meal hypothesis’. 相似文献
37.
PAULO R. GUIMARES RAFAEL L. G. RAIMUNDO CLUDIA BOTTCHER ROGRIO R. SILVA JOS R. TRIGO 《Austral ecology》2006,31(6):776-782
Abstract In several plants, extrafloral nectaries (EFN) are located close to the reproductive structures, suggesting that ants may act as a defence against specialized seed predators that overcome chemical defences. Alternatively, ants may also deter herbivores in a generalized manner, thereby protecting the whole plant. In this work, we examined the relationship between the chemically protected weed Crotalaria pallida Ait. (Leguminosae) that bears EFN, its specialized seed predator, the larvae of the arctiid moth Utetheisa ornatrix L. (Arctiidae) and ants. We tested two hypotheses related to the type of deterrence caused by ants. The Seed Predator Deterrence Hypothesis predicts that ant deterrence is directed primarily towards herbivores that destroy seeds and other reproductive structures, without attacking herbivores on vegetative structures. The General Deterrence Hypothesis states that ants are general in their effects, equally deterring herbivores in vegetative and reproductive structures. Our results supported the predictions of the Seed Predator Deterrence Hypothesis, namely, that (i) ant activity on EFN was related to the vulnerability of reproductive structures to attack by U. ornatrix; (ii) ant patrolling was restricted almost entirely to racemes; (iii) ants removed termites used as baits more frequently on racemes than on leaves; and (iv) U. ornatrix larvae were often expulsed from the racemes. These results indicate that EFN can act as another deterrent mechanism in chemically protected plants by promoting the expulsion of specialist seed predators. 相似文献
38.
Peteris Prusis Staffan Uhlén Ramona Petrovska Maris Lapinsh Jarl ES Wikberg 《BMC bioinformatics》2006,7(1):167-13
Background
Both direct and indirect interactions determine molecular recognition of ligands by proteins. Indirect interactions can be defined as effects on recognition controlled from distant sites in the proteins, e.g. by changes in protein conformation and mobility, whereas direct interactions occur in close proximity of the protein's amino acids and the ligand. Molecular recognition is traditionally studied using three-dimensional methods, but with such techniques it is difficult to predict the effects caused by mutational changes of amino acids located far away from the ligand-binding site. We recently developed an approach, proteochemometrics, to the study of molecular recognition that models the chemical effects involved in the recognition of ligands by proteins using statistical sampling and mathematical modelling. 相似文献39.
T. A. Alekhova A. V. Aleksandrova T. Yu. Novozhilova L. V. Lysak N. A. Zagustina 《Moscow University Biological Sciences Bulletin》2008,63(4):163-169
A study of the microflora of structural surfaces on board the russian segment of the international space station (RS ISS) has demonstrated that the species composition that is formed during the mission is similar to that on board the mir station. the microflora of the sampled sites was similar to that of residential and industrial buildings on earth. it was represented by 17 species of fungi, seven genera of bacteria, and three genera of actinomycetes. the degree of colonization of the surfaces of structural materials of the rs iss by destructive microorganisms was low and showed undulating dynamics. the mycelial fungi included “technophile” species, which caused biological corrosion of an aluminum-magnesium alloy in simulation experiments. 相似文献
40.