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101.
Prospective Studies Exploring the Possible Impact of an ID3 Polymorphism on Changes in Obesity Measures
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102.
Espen Burum-Auensen Paula M De Angelis Aasa R Schj?lberg Katherine L Kravik Marit Aure Ole Petter F Clausen 《The journal of histochemistry and cytochemistry》2007,55(5):477-486
The spindle checkpoint, the primary mechanism to ensure that two daughter cells receive the same amount of DNA, is compromised in many malignant tumors and has been implicated as a contributor to aneuploidy and carcinogenesis. The extent of expression and subcellular localization of the spindle proteins Aurora A, Mad2, and BUBR1 varies considerably in different immunohistochemical (IHC) reports from archival tumor tissues. Given the conflicting reports in the literature about the localization of these proteins, we examined the subcellular localization of Aurora kinase A, Mad2, and BUBR1 in normal and cancerous human tissues by IHC. In normal tissues, Aurora A was mainly localized to the nucleus when monoclonal or purified polyclonal antibodies were used, and Mad2 was localized to the nucleus, whereas BUBR1 was localized to the cytoplasm. In malignant tissues, Aurora A showed additional staining in the cytoplasm in the majority of tumors analyzed. Furthermore, BUBR1 was also localized to both the nucleus and cytoplasm in a significant fraction of tumors. Subcellular localization of Mad2 was similar in normal and malignant tissues. Thus, the validity of some earlier IHC studies of Aurora A, Mad2, and BUBR1 should be reconsidered, indicating that high-quality antibodies and a high-alkaline antigen-retrieval technique are required to achieve optimal results. We conclude that the subcellular localizations of these spindle proteins are different, although they have overlapping biological functions, and that Aurora A and BUBR1 undergo a shift in the subcellular localization during malignant transformation. 相似文献
103.
Marit Valeur Ramstad Trond E. Ellingsen Kjell D. Josefsen Hilde K. Hidal
Svein Valla
Gudmund Skjk-Brk David W. Levine 《Enzyme and microbial technology》1999,24(10):23819-646
The mannuronan C-5-epimerase AlgE2 is one of a family of Ca2+-dependent epimerases secreted by Azotobacter vinelandii. These enzymes catalyze the conversion of β-
-mannuronic acid residues (M) to -
-guluronic acid residues (G) in alginate. AlgE2 has been produced by fermentation with a recombinant strain of Escherichia coli, isolated and partially purified. Epimerization with AlgE2 increased the content of G-residues in different alginates from starting values of 0–45% up to approximately 70%. The new G-residues were mainly present in short blocks. Although G-residues may be introduced next to pre-existing G-residues, AlgE2 was not able to epimerize strictly alternating MG-structures. The epimerization with AlgE2 was greatly affected by the concentration of Ca2+. The type of alginate used as substrate affected the reaction rate and the reaction pattern especially at low Ca2+ concentration. AlgE2 appears to act by a preferred attack mechanism where the enzyme associates with different sequences in the alginate depending on the concentration of Ca2+. During epimerization, AlgE2 occasionally causes cleavage of the alginate chain. The observed frequency corresponds to 1–3 breaks per 1,000 M-units epimerized. 相似文献
104.
Marta BermejoJambrina Julia Eder Tanja M Kaptein John L van Hamme Leanne C Helgers Killian E Vlaming Philip J M Brouwer Ad C van Nuenen Marcel Spaargaren Godelieve J de Bree Bernadien M Nijmeijer Neeltje A Kootstra Marit J van Gils Rogier W Sanders Teunis B H Geijtenbeek 《The EMBO journal》2021,40(20)
The current pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) and outbreaks of new variants highlight the need for preventive treatments. Here, we identified heparan sulfate proteoglycans as attachment receptors for SARS‐CoV‐2. Notably, neutralizing antibodies against SARS‐CoV‐2 isolated from COVID‐19 patients interfered with SARS‐CoV‐2 binding to heparan sulfate proteoglycans, which might be an additional mechanism of antibodies to neutralize infection. SARS‐CoV‐2 binding to and infection of epithelial cells was blocked by low molecular weight heparins (LMWH). Although dendritic cells (DCs) and mucosal Langerhans cells (LCs) were not infected by SARS‐CoV‐2, both DC subsets efficiently captured SARS‐CoV‐2 via heparan sulfate proteoglycans and transmitted the virus to ACE2‐positive cells. Notably, human primary nasal cells were infected by SARS‐CoV‐2, and infection was blocked by pre‐treatment with LMWH. These data strongly suggest that heparan sulfate proteoglycans are important attachment receptors facilitating infection and transmission, and support the use of LMWH as prophylaxis against SARS‐CoV‐2 infection. 相似文献
105.
106.
W. Ellis Penning Marit Mjelde Bernard Dudley Seppo Hellsten Jenica Hanganu Agnieszka Kolada Marcel van den Berg Sandra Poikane Geoff Phillips Nigel Willby Frauke Ecke 《Aquatic Ecology》2008,42(2):237-251
Aquatic macrophytes are one of the biological quality elements in the Water Framework Directive (WFD) for which status assessments
must be defined. We tested two methods to classify macrophyte species and their response to eutrophication pressure: one based
on percentiles of occurrence along a phosphorous gradient and another based on trophic ranking of species using Canonical
Correspondence Analyses in the ranking procedure. The methods were tested at Europe-wide, regional and national scale as well
as by alkalinity category, using 1,147 lakes from 12 European states. The grouping of species as sensitive, tolerant or indifferent
to eutrophication was evaluated for some taxa, such as the sensitive Chara spp. and the large isoetids, by analysing the (non-linear) response curve along a phosphorous gradient. These thresholds
revealed in these response curves can be used to set boundaries among different ecological status classes. In total 48 taxa
out of 114 taxa were classified identically regardless of dataset or classification method. These taxa can be considered the
most consistent and reliable indicators of sensitivity or tolerance to eutrophication at European scale. Although the general
response of well known indicator species seems to hold, there are many species that were evaluated differently according to
the database selection and classification methods. This hampers a Europe-wide comparison of classified species lists as used
for the status assessment within the WFD implementation process. 相似文献
107.
Lenman M Sörensson C Andreasson E 《Molecular plant-microbe interactions : MPMI》2008,21(10):1275-1284
Protein phosphorylation is a key biological process that regulates reactions involved in plant-microbe interactions. The phosphorylated form of a protein often represents only a small fraction of the total population and can be problematic to analyze in a mass spectrometer. We demonstrate how a titanium dioxide (TiO(2)) resin can be employed for the enrichment of phosphoproteins, as well as a method to derivatize TiO(2)-purified phosphopeptides to facilitate determination of the exact site of phosphorylation. The use of these methods was exemplified by the identification of two plant proteins that were shown to be phosphorylated after the elicitation of Arabidopsis cells with Phytophthora infestans zoospores and xylanase. Both of the proteins that were identified, At5g54430.1 and At4g27320.1, were found to contain a universal stress protein domain with conserved residues for ATP binding. 相似文献
108.
Wesley F. C. Dáttilo Thiago J. Izzo Brian D. Inouye Heraldo L. Vasconcelos Emilio M. Bruna 《Biotropica》2009,41(5):642-646
In the tropics, several ant species are obligate inhabitants of leaf pouches and other specialized structures in plants known as myrmecophytes. However, the cues used by ant queens to locate suitable host-plants following dispersal remain poorly understood. Here we tested the hypothesis that Pheidole minutula queens use volatiles to distinguish their host Maieta guianensis (Melastomataceae) from other sympatric myrmecophytes. To do so, we used a Y-tube olfactometer to quantify the preference for volatiles of different plant species. Our results indicate that P. minutula queens discriminate the chemical volatiles produced by its host-plant from those of other sympatric ant-plant species. However, queens failed to distinguish the volatiles of Maieta from those of the ant-plant Tococa bullifera (Melastomataceae), with which P. minutula is not mutualistically associated. Nevertheless, a strong preference for Maieta over Tococa was observed during a subsequent bioassay, where the ants had physical contact with a domatium of each plant species. These results suggest that additional, short distance mechanisms are also necessary for host discrimination. Overall, our findings suggest that the high degree of compartmentalization observed in symbiotic ant–plant relationships is achieved, at least in part, by the relatively high degree of specificity in host selection displayed by foundress queens. 相似文献
109.
There has been increasing interest in the mechanisms that mediate behavioral and physiological plasticity across individuals with similar genotypes. Some of the most dramatic plasticity is found within and between social insect castes. For example, Polistes wasp queens can nest alone, dominate a group of cooperative queens, or act as worker-like subordinates who rarely reproduce. Previous work suggests that condition-dependent endocrine responses may play a role in plasticity between castes in the hymenoptera. Here, we test whether condition-dependent endocrine responses influence plasticity within castes in the wasp Polistes dominulus. We experimentally manipulate juvenile hormone (JH) titers in nest-founding queens and assess whether JH mediates variation in behavior and physiology. JH generally increased dominance and fertility of queens, but JH's effects were not uniform across individuals. JH had a stronger effect on the dominance and fertility of large individuals and individuals with facial patterns advertising high quality than on the dominance and fertility of small individuals and those advertising low quality. These results demonstrate that JH has condition-dependent effects. As such, they clarify how JH can mediate different behaviors in well nourished queens and poorly nourished workers. Many Polistes queens nest cooperatively with other queens, so condition-dependent hormonal responses provide a mechanism for queens to adaptively allocate energy based on their probability of successfully becoming the dominant queen. Research on the endocrine basis of plasticity often focuses on variation in endocrine titers alone. However, differential endocrine responses are likely to be a widespread mechanism mediating behavioral and physiological plasticity. 相似文献
110.
Marit Wagner 《Inorganica chimica acta》2009,362(13):4809-3158
The coordination chemistry of a chiral tripodal ligand L containing pyridyl, imidazolyl and pyrazolyl donor functions has been investigated in combination with zinc(II). While the reaction of a racemic mixture of L with ZnX2 (X = Cl, Br) leads to complexes LZnX2 with tetrahedrally coordinated zinc centres (the pyridyl donor function remains pending), the employment of Zn(ClO4)2 leads to the sandwich complex [L2Zn](ClO4)2 which due to the two possible configurations for L (S and R) occurs in form of two diastereomers (the meso form and the enantiomeric pair SS/RR). The crystal structures of all three compounds are discussed. 相似文献