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101.
The groin flap in reparative surgery of the hand 总被引:2,自引:0,他引:2
J A Chow Z J Bilos P Hui R F Hall A E Seyfer A C Smith 《Plastic and reconstructive surgery》1986,77(3):421-426
The historical literature of the use of axial vascular pattern flaps from the hypogastric and iliofemoral regions in reparative surgery of the hand is concisely reviewed. Thirty-six iliofemoral (groin) flaps were utilized for delayed primary resurfacing and secondary reconstruction of defects of the hand and forearm. Two flaps (6 percent) were complicated by partial necrosis. We caution against the immediate resurfacing (within 24 hours of injury) of acute crushed hand wounds by distant flaps. The immediate application of a healthy flap on a soiled or crushed wound invites complications of local tissue necrosis, infection, and subsequent loss of the flap. When distant flaps are indicated for coverage of acute hand wounds, delayed primary coverage following complete removal of all nonviable tissue is a safe and reliable regimen. It is advantageous to design the serviceable portion of the flap on the distal area of the vascular territory of the groin flap. Thoughtful yet "radical" defatting can be performed on the lateral portion of the groin flap territory. Constructed in this way, the long medial base of the groin flap allows freedom for movement at the wrist and metacarpophalangeal and interphalangeal joints, thus decreasing edema and stiffness. In the management of soft-tissue defects in the hand requiring distant flap coverage, we choose to utilize the conventional groin flap in preference to the microvascular free flap when both techniques will deliver equal results. 相似文献
102.
103.
This paper investigates the problem of spontaneous pattern discrimination by the visual system of the fly. The indicator for discrimination and attractivity of a pattern is the yaw torque of a test fly. It is shown that the pattern discrimination process may be treated as a special (degenerate) case of figureground discrimination which has been described in detail in earlier publications. Decisive for the discrimination process is the fact that pattern discrimination by the fly is mediated by motion detectors which respond not only a pattern velocity but also to structural properties of pattern contrast. This is demonstrated by the transition from the existing twodimensional array of motion detectors to a continuous detector field which enabled us to calculate instantaneous detector responses to instationary pattern motion. The new approach, together with the special theory for figure-ground discrimination, is then applied to predict spontaneous discriminations of onedimensional periodic patterns. It is shown that predictions and experimental results are in good agreement. The second set of discrimination experiments deals with two dimensional dot patterns for which a quantitative theory is not yet available. However, it is shown that the attractivity of a dot pattern crucially depends on both the orientation and the direction of motion relative to the fly's eyes. If the contrast of a moving dot elicits an event in a motion detector which through the detector's time constant leads to an interference with an event received by a preceeding dot, the attractivity of the dot pattern is diminished. In the discussion relations are drawn between the concepts of pattern discrimination in honey bees and the theoretical aspects of discrimination put forward in this paper. It is briefly discussed why a two-dimensional motion detector theory might become the key for an understanding of pattern categories like figural intensity and figural quality. 相似文献
104.
Antitubulin, phalloidin, and antimyosin were used to study the distribution of microtubules, microfilaments, and myofibrils in cultured adult cardiomyocytes. These cells undergo a stereotypic sequence of morphological change in which myotypic features are lost and then reconstructed during a period of polymorphic growth. Microtubules, though rearranged during these events in culture, are always present in an organized network. Myosin and actin structures, on the other hand, initially degenerate. This initial degeneration is reversed when a cell attaches to the culture substratum. Upon attachment, new microtubules are laid down as a cortical network adjacent to the sarcolemma and, subsequently, as a network in the basal part of the cell. Actin and then myosin filament bundles appear next, in a pattern corresponding to the pattern of the microtubules. Finally, striated myofibrils are formed, first in the central part of the cell, and subsequently in the outgrowing processes of the cell. A mechanism is suggested by which the eventual polymorphic shape of a cell is related to the shape of its initial area of contact with the culture substratum. Finally, a model of myofibrillogenesis is proposed in which microtubules participate in the insertion of myosin among previously formed actin filament bundles to produce myofibrils. 相似文献
105.
The polymorphic phase behaviour of dilinoleoylphosphatidyethanolamine (DLPE) and 1-palmitoyl-2-oleoylphosphatidylcholine (POPC) is investigated by freeze-fracture electron microscopy, X-ray diffraction and 31P-NMR. The structures at 5% or less POPC are predominantly inverted hexagonal (HII), whereas at 15% or more POPC, the structure is mostly bilayer (L), interrupted by defects (lipidic particles). A cubic phase structure is observed in the transition range between H and L phases; the cubic arrangement deteriorates at higher temperatures into an amorphous aggregate of spherical units. Both cubic and amorphous structures contribute to the isotropic 31P resonance, with no preference for PC or PE partitioning in the isotropic motion as observed by high resolution NMR. The existence of the cubic phase seems to depend critially on the homogeneity and the degree unsaturation of the phospholipids. 相似文献
106.
Purification and characterization of an enkephalin aminopeptidase from rat brain membranes 总被引:6,自引:0,他引:6
A membrane-bound aminopeptidase was purified from rat brain, and its activity was assayed by high-pressure liquid chromatography with Met-enkephalin as the substrate. The enzyme was extracted with 1% Triton X-100 and purified by chromatography, successively on DEAE-Sepharose CL-6B, Bio-Gel HTP, and Sephadex G-200 columns. The overall purification was about 1200-fold, with 25% yield. The purified enzyme showed one band on disc gel electrophoresis and two bands on sodium dodecyl sulfate electrophoresis with molecular weights of 62 000 and 66 000. The aminopeptidase has a pH optimum of 7.0, a Km of 0.28 mM, and a Vmax of 45 mumol (mg of protein)-1 min-1 for Met-enkephalin. It releases tyrosine from Met-enkephalin, but it does not split the byproduct. It does not hydrolyze gamma- or beta-endorphin, or dynorphin, but it does hydrolyze neutral and basic aminoacyl beta-naphthylamides. The enzyme is inhibited by the aminopeptidase inhibitors amastatin, bestatin, and bestatin-Gly. Its properties, such as its subcellular localization, substrate specificity, pH optimum, and molecular weight, distinguish it from leucine aminopeptidase, aminopeptidase A, aminopeptidase B, aminopeptidase M, and the soluble aminopeptidase for enkephalin degradation. 相似文献
107.
108.
<正> 胎盘型碱性磷酸酶(P-ALP)是碱性磷酸酶(EC3.1.3.1.ALP)的一种同工酶。P-ALP除出现于妊娠妇女血清外,一些学者还从恶性肿瘤患者血清中发现此酶,并证明它是一种特异性较强的肿瘤标志物。据此,建立P-ALP的简易纯化方法,制备纯度较高的酶制品是建立P-ALP灵敏的微量检测法的先决条件。本文报道以L-苯丙氨酸(L-phe)为配基,用氯代环氧丙烷活化Sepharose 4B的亲和层析法,从人胎盘纯化P-ALP,并对其部分性质进行了研究。 相似文献
109.
用多孔强碱型三乙醇胺基聚苯乙烯阴离子交换树脂做为载体,用CNBr与载体上的多羟基作用共价偶联了胰酶。红外光谱表明:其共价偶联反应机理与用CNBr活化多糖类载体并接酶的机理相类似。最适偶联条件研究表明:CNBr用量增多,酶蛋白载量增加。但比活下降。偶联pH为10时,固定化酶有适宜的载量和较高的比活。由于胰酶水解蛋白反应释放出H~+质子,这些质子在载体内积累,使微环境内H~+质子浓度增加,进而使得固定化胰酶的pH—活性曲线在pH9~11范围内未出现下降。在变温和60℃恒温下对固定化酶的热稳定性测试表明:固相酶的热稳定性比天然酶的热稳定性有所提高。 相似文献
110.
寄生于樟、阴香和肉桂等植物上的泽田外担菌和油盘孢属真菌,几十年来分类上存在许多不同看法,或全部归泽田外担菌,或全部归油盘孢属,把此二类不同真菌混淆起来,造成名称混乱。本文通过形态学的研究,表明泽田外担菌与油盘孢属的区别是:泽田外担菌具担子层,担孢子4—8个生担子上,寄主是樟树;而油盘孢属的孢子生菌丝上,形成孢子堆,寄主是阴香和肉桂等植物。 相似文献