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1.
2.
Influence of prey species and stages on predatory efficiency and development of two phytoseiid mites
The effect of prey species and the different stages of prey on the predatory efficiency and biology of the phytoseiid mites,Amblyseius gossipi
Elbadry andTyphlodromus mangiferus sp. n. was studied. It was found that feeding either predator onTetranychus cucurbitacearum (Sayed) promoted faster development and a higher rate of oviposition than rearing on the twospotted spider mite,T. urticae (Koch). Different stages of both prey species also produced different responses in the biological activities of these predaceous
mites.
Résumé On a étudié l'effet de l'espèce de la proie et de ses différents stades sur l'efficacité et la biologie des acariens phytoseiides,Amblyseius gossipi Elbadry etTyphlodromus mangiferus sp. n. Il a été constaté que l'alimentation des 2 prédateurs avecTetranychus cucurbitacearus (Sayed) assure un dévelopment plus rapide et une fécondité plus élevée que leur élevage surT. urticae (Koch). Les différents stades de ces 2 proies produisent des réponses différentes dans les activités biologiques des 2 acariens prédateurs.相似文献
3.
B. Pernet-Coudrier G. Varrault M. Saad J. P. Croue M.-F. Dignac J.-M. Mouchel 《Biogeochemistry》2011,106(1):89-106
Understanding the nature of organic matter is a necessary first step in assessing contaminant bioavailability and allowing
water supply managers to optimise the treatment train in the aim of providing safe and inexpensive drinking water. This study
provides further insight into the composition, structure and functional groups of dissolved organic matter (DOM) (both hydrophobic
and hydrophilic) from urban aquatic systems by means of various analytical techniques (DAX-8/XAD-4 fractionation, elemental
analysis, UV and FTIR spectroscopies, 13C and 15N isotopic analysis, size exclusion chromatography and Pyrolysis-GC-MS). The analytical range chosen for this study constitutes
a powerful tool in the characterisation of DOM in urban water. The inclusion of information from one technique to the next
might not only serve as a support to each one, but also as a complement. The DOM fraction from treated effluent and, more
generally, DOM from urban water (i.e. receiving treated effluent) display a strong hydrophilic characteristic [i.e. low humic
substance (HS) content, low SUVA], along with a high distribution in molecular weights observed by SEC and low average molecular
weight. Due to the origin of this DOM, proteinaceous structures constitute the main compounds, as observed by FTIR and Py-GC-MS.
Such characteristics (i.e. heterogeneity, low average molecular weight and diverse functional groups, which make up a total
of N) could explain that DOM from treated effluent displayed a strong reactive potential metals pollutants as previously demonstrated. 相似文献
4.
Active oxygen species are generated in cells during pathophysiologic conditions such as illflammation and postischemic reperfusion. If oxygen radical scavengers are added before reperfusion, then the magnitude of injury is reduced. We inves-tigated whether free radicals generated following exposure to hypoxia and reoxygenation activate voltage-dependent K+ ion channels in tumor cells in vitro. Using the technique of whole cell voltage clamping, we recorded currents from two families of potassium (K+) channels that were activated following reoxygenation. One of these groups possessed the electrophysical characteristics of a tetraethylammonium (TEA)-sensitive delayed rectifier channel and the other possessed characteristics of a Tea-insensitive slow inactivating channel. We present evidence which suggests that K+ channels are activated following reoxygenation but not during the hypoxia phase. The K+ currents decayed with time following reoxygenation. The decay characteristics of the K+ currents depended on the duration and level of hypoxia to which the cells were exposed. To determine whether activation of K+ channels by reoxygenation was initiated by free radicals, we pretreated cells with N-Acetyl L-Cysteine (NAC), a free radical scavenger, and found that this pretreatment abolished the currents induced by reoxygenation. We also present evidence that free radicals do not directly act on the channel itself, but activate a protein kinase which, in turn, activates the K+ channels. Taken together, these results indicate that one of the early responses to oxidative stress is the activation of K+ currents. © 1993 Wiley-Liss, Inc. 相似文献
5.
The antigenic determinants for two monoclonal antibodies directed against horse apo-cytochrome c, a protein of disordered structure, as judged by spectroscopic and hydrodynamic criteria, have been studied by a combination of methods: antigen competition in solution by radio immunoassay and enzyme-linked immunoassay, and differential acetylation of free and antibody-bound antigen. In the latter method the accessibility of lysine residues of the antigen in the antigen-antibody complex is compared to the accessibility in the free antigen. The two antibodies against the heme-free protein do not recognize intact native cytochrome c, but they crossreact with the heme-containing peptides 1-38 and 1-65 of cytochrome c. The antigenic determinant recognized by monoclonal antibody SJL 2-4 is conformational and discontiguous, it is composed of residues close to the N-terminus and around position 25. The other monoclonal antibody, Cyt-1-59, seems to recognize a contiguous epitope close to the N-terminus. The present results show that even a seemingly disordered protein which is conventionally classified as a random coil may feature subtle spatial regularities. The presence of ordered conformational elements in apocytochrome c may be important for the enzyme-catalyzed covalent attachment of the heme and the import of cytochrome c into mitochondria. A discontiguous determinant for SJL 2-4 is particularly interesting because this antibody inhibits the proliferation of a T-cell clone specific for apo-cytochrome c [Corradin & Engers (1984) Nature (Lond.) 308, 547-548]. 相似文献
6.
A single dose of zearalenone (10 g/g LBW) was injected intraperitoneally to Wistar Albino rats at the age of 50–100 days. The uterine acetyl cholinesterase enzyme was significantly increased in the treated animals compared to that in the controls. Therefore, zearalenone would be considered as an esterogenic effector for increasing the uterine acetyl cholinesterase which enhances uterine relaxation and subsequently improves its function for pregnancy in prematured-animals.Unlike estradiol, it was interesting to find that the estrogenicity of zearalenone was increased by the moderating progesterone hormone. Moreover, it was revealed in this study that the injected dose of zearalenone had no deleterious effects on the pregnant rats at 10–12 days period of gestation. The harmful effects of zearalenone on pregnant animals cited in the literature (11, 13, 19) were reviewed. 相似文献
7.
Summary The N-metabolism ofArthrocnemum fruticosum (L.) Moq., growing in a saline area north-east of the Dead Sea in Jordan, was studied over its vegetative growth period from
March to September 1981. Plant and soil samples were taken at monthly intervals. Water content, Na+, K+, Cl−, NH
4
+
, NO
2
−
and NO
3
−
concentrations were determined in the soil extracts, and the same determinations plus ash weight, soluble carbohydrates,
proline, proteins andin vivo nitrate reductase in the plant roots and shoots.
Soil humidity decreased and salinity increased from March to August, with re-wetting occurring in late July. K+ and Cl− were much lower in the soils than Na+. Plant relative dry weight increased during summer due to the absorption of Na+ in addition to increased organic dry weight. The uptake of Na+ was not balanced by a similar uptake of Cl−.
Ammonium and nitrate decreased in soil and plants in parallel with increasing salinity. Nitrite was only found in the roots
and always in very low quantities. Proline was found only in March. The total soluble carbohydrates in the roots showed a
short increase in June when the sodium in the plants also increased. It was concluded that carbohydrates may be used to balance
osmotic shocks, but that another compatible compounds is necessary to maintatin long-term osmotic equilibrium.
The nitrate reductase activity, measuredin vivo, and the soluble protein changed roughly in parallel with the internal nitrate from May to August, suggesting that nitrogen
uptake and reduction in the plant is inhibited during summer when the soil is dry and very saline. This could be a direct
effect of drought and/or salinity on the plants, or an indirect onevia an inhibition of nitrifying bacteria. 相似文献
8.
A Flow Cytometric method for the evaluation of the phagocytic capacity of bovine blood neutrophils is described. The neutrophils were isolated from bovine blood by a one step discontinuous gradient of Percoll. By this technique of isolation, 90 ± 2.8 % (mean ± s) of the granulocytes in the whole blood were recovered. Isolated neutrophils were incubated with FITC labeled S. aureus or zymosan particles in a ratio of 1:20 and 1:10, respectively, and a final serum concentration of 10 %. Phagocytosis was terminated after 15 min and the number of extracellular bacteria or zymosan particles and the percentage of phagocytic granulocytes were registered by Flow Cytometry (FCM). FCM and microscopic studies revealed that eosinophils play a minor role in the phagocytosis of bacteria. The neutrophils were the main population of the granulocytes which were actively phagocytic. Variation among cows in the ability of their blood neutrophils to phagocytize bacteria was evident. 相似文献
9.
Dr. María Cristina Maldonado Ana María Strasser de Saad Danley Callieri 《Current microbiology》1989,18(5):303-306
Several recent reports have described large numbers of monoclonal antibodies that cross-react with toxins A and B ofClostridium difficile; this suggests that the toxins share major epitopes. Our results show that monoclonal antibodies (MAb) against other antigens bind nonspecifically to both toxins. Therefore, we believe that the cross-reacting MAb bind by this manner and not by a true immune reaction. 相似文献
10.
Serial concentrations of aflatoxin B1 ranging from 200 to 1500 p.p.b. in 2% lactic acid solution (which is the aimed concentration of lactic acid in fresh silage) were assayed for detoxification. Thin-layer chromatography analysis, revealed a complete transformation of 1 000 p.p.b. of aflatoxin B1 to a new fluorescing compount corresponding to aflatoxin B2a which is referred to as hydroxydihydro-aflatoxin B1 toxicity test on chickens confirmed Ciegler's findings (4). The results confirm that the chemical changes taken place in the silo can detoxify aflatoxin B1 to aflatoxin B2a. 相似文献