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991.
Sara Beros Evelien Jongepier Felizitas Hagemeier Susanne Foitzik 《Proceedings. Biological sciences / The Royal Society》2015,282(1819)
Parasites can induce alterations in host phenotypes in order to enhance their own survival and transmission. Parasites of social insects might not only benefit from altering their individual hosts, but also from inducing changes in uninfected group members. Temnothorax nylanderi ant workers infected with the tapeworm Anomotaenia brevis are known to be chemically distinct from nest-mates and do not contribute to colony fitness, but are tolerated in their colonies and well cared for. Here, we investigated how tapeworm- infected workers affect colony aggression by manipulating their presence in ant colonies and analysing whether their absence or presence resulted in behavioural alterations in their nest-mates. We report a parasite-induced shift in colony aggression, shown by lower aggression of uninfected nest-mates from parasitized colonies towards conspecifics, potentially explaining the tolerance towards infected ants. We also demonstrate that tapeworm-infected workers showed a reduced flight response and higher survival, while their presence caused a decrease in survival of uninfected nest-mates. This anomalous behaviour of infected ants, coupled with their increased survival, could facilitate the parasites'' transmission to its definitive hosts, woodpeckers. We conclude that parasites exploiting individuals that are part of a society not only induce phenotypic changes within their individual hosts, but in uninfected group members as well. 相似文献
992.
Sven Dnicke Erik Bannert Tanja Tesch Susanne Kersten Jana Frahm Susanne Bühler Helga Sauerwein Solvig Grs Stefan Kahlert Hermann-Josef Rothktter Cornelia C Metges Jeannette Kluess 《Innate immunity》2020,26(8):716
The sensitivity of pigs to deoxynivalenol (DON) might be influenced by systemic inflammation (SI) which impacts liver. Besides following acute-phase proteins, our aim was to investigate both the hepatic fractional albumin (ALB) synthesis rate (FSR) and the ALB concentration as indicators of ALB metabolism in presence and absence of SI induced by LPS via pre- or post-hepatic venous route. Each infusion group was pre-conditioned either with a control diet (CON, 0.12 mg DON/kg diet) or with a DON-contaminated diet (DON, 4.59 mg DON/kg diet) for 4 wk. A depression of ALB FSR was observed 195 min after LPS challenge, independent of feeding group or LPS application route, which was not paralleled by a down-regulated ALB mRNA expression but by a reduced availability of free cysteine. The drop in ALB FSR only partly explained the plasma ALB concentrations which were more depressed in the DON-pre-exposed groups, suggesting that ALB levels are influenced by further mechanisms. The abundances of haptoglobin, C-reactive protein, serum amyloid A, pig major acute-phase protein, fibrinogen and LPS-binding protein mRNA were up-regulated upon LPS stimulation but not accompanied by increases in the plasma concentrations of these proteins, pointing at an imbalance between synthesis and consumption. 相似文献
993.
Susanne M. Mumby Debbie Abbott-Brown Gregory J. Raugi Paul Bornstein 《Journal of cellular physiology》1984,120(3):280-288
Thrombospondin (TS), a 450,000 molecular weight glycoprotein, is released from α-granules of thrombin-activated platelets and is secreted and incorporated into the extracellular matrix by several cell types in culture. We have examined the effects of cell density and transformation on the production of TS in cell culture. The levels of TS, per cell, in the culture medium of endothelial cells, smooth muscle cells, and fibroblasts were greater at lower cell densities; in fibroblasts the levels of two other extracellular matrix proteins, fibronectin and collagen, were unaffected by cell density. Our evidence indicates that the higher levels of TS in the culture medium, determined for lower-density cells, were achieved by an increased secretion of the protein rather than by a reduction in degradation or incorporation into the extracellular matrix. TS production by normal and transformed Wl-38 fibroblasts was the same, although the fibronectin level in the culture medium of the transformed cells was substantially decreased. These findings suggest that the production of TS by cells in culture is regulated in a different fashion from that of fibronectin or collagen. 相似文献
994.
The relationship between the gas-exchange characteristics of attached leaves of Amaranthus edulis L. and the contents of photosynthetic intermediates was examined in response to changing irradiance and intercellular partial pressure of CO2. After determination of the rate of CO2 assimilation at known intercellular CO2 pressure and irradiance, the leaf was freeze-clamped and the contents of ribulose-1,5-bisphosphate, glycerate-3-phosphate, fructose-1,6-bisphosphate, glucose-6-phosphate, fructose-6-phosphate, triose phosphates, phosphoenolpyruvate, pyruvate, oxaloacetate, aspartate, alanine, malate and glutamate were measured. A comparison between the sizes of metabolite pools and theoretical calculations of metabolite gradients required for transport between the mesophyll and the bundle-sheath cells showed that aspartate, alanine, glycerate-3-phosphate and triose phosphates were present in sufficient quantities to support transport by diffusion, whereas pyruvate and oxaloacetate were not likely to contribute appreciably to the flux of carbon between the two cell types. The amounts of ribulose-1,5-bisphosphate were high at low intercellular partial pressures of CO2, and fell rapidly as the CO2-assimilation rate increased with increasing intercellular partial pressures of CO2, indicating that bundle-sheath CO2 concentrations fell at low intercellular partial pressures of CO2. In contrast, the amount of phosphoenolpyruvate and of C4-cycle intermediates declined at low intercellular partial pressures of CO2. This behaviour is discussed in relation to the co-ordination of carbon assimilation between the Calvin and C4 cycles.Abbreviations PEP
phosphoenolpyruvate
- PGA
glycerate-3-phosphate
-
p
i
intercellular CO2 pressure
- RuBP
ribulose-1,5-bisphosphate
- triose-P
triose phosphates 相似文献
995.
996.
Zusammenfassung Eine Pilotstudie zur Auswilderung des Waldrapps wurde unter Berücksichtigung der Sozialstruktur durchgeführt. Da Waldrappe ihre Jungen bis zur nächsten Brutsaison führen, mußten zwei menschliche Pflegeeltern die Aufzucht- und Führungsrolle übernehmen. Sechs Jungvögel wurden zunächst von Hand aufgezogen und lange vor dem Flüggewerden an den Auflassungsort gebracht. Sie erhielten weitgehend natürliche Nahrung und wurden auch nach dem Ausfliegen von den beiden Pflegepersonen betreut. Somit wurde eine Familienstruktur geschaffen, die den Jungvögeln einerseits ein gefahrloses Erkunden ihrer Umwelt ermöglichte, andererseits eine zu große Zahmheit gegenüber Fremdpersonen verhinderte. In Feindmeidung, Nahrungssuch-Strategien und Nahrungwahl verhielten sie sich wie gleichaltrige Vögel aus Freilandpopulationen. Der positive Ausgang war Vorausbedingung für eine Auswilderung in Südspanien, die nach gleicher Methode ablaufen wird.
Successful introduction of Waldrapp Ibis (Geronticus eremita) on the basis of family bonding — a pilot study in Austria
Summary In 1991, the Alpenzoo Innsbruck/Tirol initiated a pilot study to test a new method for releasing the highly endangered Waldrapp Ibis into its natural habitat based on the complex social system and tight family bonds of this highly social species. Young Waldrapp Ibises have a very close contact with their parents, usually up to the next breeding season. Especially in the first fledgling days the guidance of the parents is indispensable. Six chicks of the colony in the Alpenzoo were handreared to produce parent imprinting. In order to achieve food imprinting the birds were fed to a large extend on insects wich constitute their natural food. Handrearing took place at the releasing station, an adapted farmhouse near Innsbruck. Two human foster parents stayed continuously with the fledglings for six month. The simulated family structure enabled the young birds to get familiar with the habitat and to learn foraging whilst enjoying permanent protection. Being guided by only two persons the birds did not become too tame; they ignored other people and learned to avoid dangerous man made situations (e.g. cars, roads, dogs). The ability of our birds to orientate, their feeding behaviour, choice of food and use of habitat were identical to what is known of Waldrapp Ibises of the same age living in the wild, for example in the colonies in Morocco. The successful pilot study is considered to be the basis for a releasing program intended in a protected area of southern Spain.相似文献
997.
998.
Summary Fibroblasts from a heterozygous carrier for the Martin-Bell syndrome, who manifests the fragile site Xq27, were cloned to separate the population carrying the primary defect on the active X chromosome from the population with this defect on the inactive X. Clones with this defect on the active X manifest the fra(X)(q27) whereas clones from the other population are fra(X)-negative (Steinbach et al. 1983b). In this project, the replication status of the X chromosome manifesting the fra(X)(q27) was studied in seven clones with this defect on the active X.The results obtained on the clones were very similar to the results obtained from uncloned fibroblasts and lymphocytes. In the clones the fragile site was found manifested on the early replicating X in 73 cells and on the late replicating X in four cells.Since the defect is located on the active X chromosome of these cells the manifestation of the fragile site on the late replicating X suggests that the defect and the fragile site cannot be identical. It is concluded that there is no obligate synteny of this defect and the manifested fragile site. 相似文献
999.
1000.
Joana M. Murad Susanne H. Baumeister Lillian Werner Heather Daley Hélène Trébéden-Negre Jake Reder Charles L. Sentman David Gilham Frederic Lehmann Sarah Snykers Marie-Louise Sentman Terri Wade Adam Schmucker Michael W. Fanger Glenn Dranoff Jerome Ritz Sarah Nikiforow 《Cytotherapy》2018,20(7):952-963