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941.
Vanillic, syringic, gallic, and protocatechuic acids, methyl-p-hydroxybenzoate, and propyl-p-hydroxybenzoate generally inhibited respiration in vitro of Escherichia coli, Proteus vulgaris, Pseudomonas aeruginosa, and Aerobacter aerogenes in human urine. In the absence of any other available carbon source, certain of the phenolic compounds were utilized. Reproduction was generally suppressed in urine buffered to pH 7, 5.6, 4.5, and 4.0. The phenolic compounds were used in the range of 0.11 to 0.99 μmole/ml. 相似文献
942.
R. Hasselback Marja Soots John Curtis G. L. Robertson D. H. Cowan G. D. Hart 《CMAJ》1967,96(25):1610-1614
The presence of definite cytoplasmic granulation in at least some of the malignant cells was used as the sole criterion to separate 156 patients with acute leukemia into two groups: 110 with myeloblastic (AML), and 46 with lymphoblastic or stem cell leukemia (ALL). The median survival from the onset of symptoms in patients with AML was 20 weeks, and those with ALL 37 weeks. The difference in survival in these two groups is much greater for patients under the age of 25 than for those over the age of 25. 相似文献
943.
944.
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947.
The parathyroid glands have received relatively little attentionwith regard to their impact on the internal milieu in amphibians.Present information, however, clearly indicates that distributionof mineral in frog tissues and body fluids is under hormonalregulation; further modifications are imposed by season andtemperature. Under conditions of cold acclimation or duringwinter normal amphibian bone shows minimal rates of carbohydrateutilization: simultaneously, phosphate is conserved by reducedexcretion and increased incorporation in tissue. Exogenous parathyroidhormone, injected under these conditions when endogenous titersmay be low due to glandular degeneration, reverses these effects,and phosphate is lost in a hyperphosphaturic urine. During summeror periods of warm acclimation, hormone promotes incorporationof phosphate in tissues, and increases rates of carbohydratemetabolism in bone; citric acid, which may act in solubilizingbone mineral, is elevated in the bone. Concurrently, pre-existingsulfated mucopolysaccharides of "old" bone may be degraded,while epiphyseal zones enlarge and may exhibit accelerated orabnormal elaboration of sulfated components of cartilage and/orosteoid matrix. 相似文献
948.
1. Methyl retinoate has been converted into methyl 5,6-monoepoxyretinoate by reaction with monoperphthalic acid. The epoxy acid ester on alkaline hydrolysis gave 5,6-monoepoxyretinoic acid. 2. Treatment of the 5,6-monoepoxy compounds with ethanolic hydrochloric acid gave the corresponding 5,8-epoxy (furanoid) compounds. 3. With lithium aluminium hydride, the acid and the ester groups were selectively reduced to primary alcohols. 4. Administration of methyl 5,6-monoepoxyretinoate intraperitoneally and subcutaneously had good growth response in vitamin A-deficient rats. 5. 5,6-Monoepoxyretinoic acid, when given intraperitoneally as the sodium salt, was 157% as active as all-trans-retinyl acetate. 6. Methyl 5,6-monoepoxyretinoate was hydrolysed to the epoxy acid by rat-liver homogenate. It had 35% of the biological activity of all-trans-retinyl acetate in the rat when given orally. 相似文献
949.
Electron microscopy was used to study pollen wall ontogeny in Zea mays. The initial stage of development consisted of compartmentalization of microspores within callose special walls. Microspore plasma membranes retracted and tubular elements of the endoplasmic reticulum became perpendicularly oriented to the plasma membranes. Evaginations of the endoplasmic reticulum into the microspore plasma membrane resulted in the establishment of a template or blueprint of the mature pollen wall. Sporopollenin deposition upon the template began immediately after dissolution of the callose special walls and release of the microspores into the anther locule. The columellae were the first pollen wall units to be formed; the tectum and foot layer became established shortly thereafter. The granular endexine was the last-formed unit. The relationships of membrane systems to the ontogeny of the pollen wall units and the mode of pollen wall growth are discussed. 相似文献
950.
John M. Shackleford 《American journal of physical anthropology》1966,25(3):291-297
Indian bones from Mississippian and Archaic periods were examined by the techniques of electron microscopy and electron diffraction. Specimens of all ages containing intact mineral constituents showed numerous areas in which the apatite crystals exhibited typical periodic banding as seen in hard tissues of recent age. Diffraction patterns from the same areas verified the morphological appearance. Phosphotungstic acid stained, decalcified sections exhibited collagen fibrils with typical periodic banding regardless of age or soil conditions. In specimens of Archiac age there were a greater number of “poorly preserved” areas as compared with bones from Mississipian excavations. In these areas the collagen appeared to be degraded and the apatite crystals were randomly oriented. No attempt to quantitate the age changes was made in view of the inherent limitations of the method of investigation. 相似文献