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1.
2.
Sulfoconjugates occur ubiquitously as sulfopolysaccharides, sulfolipids and sulfoproteins. A variety of sulfotransferases
catalyze the sulfation process with 3’-phosphoadenosine 5’-phosphosulfate as the sulfate donor. Sulfatases that catalyze the
desulfation of different sulfoconjugates are known to be deficient in a number of genetic storage disorders. 相似文献
3.
Kiyoshi Akeo Yasuhiko Tanaka Tatsuji Fujiwara 《In vitro cellular & developmental biology. Plant》1988,24(7):705-710
Summary The endocytotic process in cultured human RPE cells was observed after 1 min, 20 min, and 2 h incubation with cationized ferritin.
Within 1 min the ferritin particles were seen to attach to the cell membrane, especially between microvilli. Uncoated and
coated pits could be recognized on the cell membranes, and uncoated and coated endocytotic vesicles were found in the cytoplasm
after 20 min of incubation. These vesicles were surrounded by abundant microfilaments and had no visible membranes. Loss of
membrane may be an initial step in the process of developing into the irregular clumps of ferritin particles found inside
the plasma membrane. With time, more irregular clumps of ferritin, smaller than the particles introduced during incubation,
appeared just beneath the cell membrane. Lysosomes were adjacent to the clumps of ferritin particles associated with microtobules
and finally degraded these particles. The phagolysosomes containing many particles were surrounded by many microtubules. Small
ferritin particles surrounded but had not entered the rough endoplasmic reticulums, and no particles were seen either around
or in the Golgi apparatus.
Presented at the 7th International Congress of Eye Research, Nagoya, Japan, 27 September 1986. 相似文献
4.
The wake and sleep-onset times of a patient with a sleep-wake cycle longer than 24 hr were recorded by the patient for 4 years. During this time, the patient found himself unable to maintain a 24-hr sleep-wake schedule. When treated with 1-2 mg clonazepam, taken nightly, he was able to become entrained to a 24-hr day. Despite entrainment of his sleep-wake cycle, the patient reported depression, lack of motivation and fatigue and chose not to continue taking the drug. 相似文献
5.
Some factors controlling cell polarity in chick retinal pigment epithelial cells in clonal culture 总被引:1,自引:0,他引:1
B.J. Crawford 《Tissue & cell》1983,15(6):993-1005
In clonal culture differentiated chick retinal pigmented epithelial (RPE) cells form a monolayer which shows little or no cellular division. The cells usually rest on a basal and reticular lamina and are polarized with their apical surface towards the medium. The apical surface is characterized by apical protrusions, an extensive apical web of microfilaments and junctional complexes which join the apical-lateral borders. A PA/S positive material with a felt-like appearance from the serum component of the medium coats the surfaces of the tissue culture plates. A similar material is found on any membrane filter which has been exposed to medium containing serum. When such a filter brought in contact with the upper surfaces of the RPE cells, the apical surface characteristics are lost, the cells often accumulate Alcian Blue positive material between the cells and the filter and secrete a reticular and a basal lamina, i.e. they establish a second basal surface. Once this has occurred, the cells appear to either detach from the plate and reverse their polarity, or undergo division forming two cell layers. In the latter case new apical surfaces are created between the cell layers but the cells appear to join to form circular structures rather than sheets. These results suggest that contact with this felt-like material initiates formation of a basal surface. They further suggest that where the apical surface has been converted to a basal one the cell attempts to restore the apical surface either by separating from the plate and reversing its polarity or by creating circular structures and developing new apices oriented toward the center of the circle. 相似文献
6.
Randolph M. Nesse M.D. 《Human nature (Hawthorne, N.Y.)》1990,1(3):261-289
Emotions can be explained as specialized states, shaped by natural selection, that increase fitness in specific situations. The physiological, psychological, and behavioral characteristics of a specific emotion can be analyzed as possible design features that increase the ability to cope with the threats and opportunities present in the corresponding situation. This approach to understanding the evolutionary functions of emotions is illustrated by the correspondence between (a) the subtypes of fear and the different kinds of threat; (b) the attributes of happiness and sadness and the changes that would be advantageous in propitious and unpropitious situations; and (c) the social emotions and the adaptive challenges of reciprocity relationships. In addition to addressing a core theoretical problem shared by evolutionary and cognitive psychology, explicit formulations of the evolutionary functions of specific emotions are of practical importance for understanding and treating emotional disorders. 相似文献
7.
Yuichi Mazaki Makoto Mochii Ryuji Kodama Goro Eguchi 《Development, growth & differentiation》1996,38(4):429-437
When retinal pigmented epithelial cells (PEC) of chick embryos are cultured under appropriate conditions, the phenotype changes to that of lens cells through a process known as transdifferentiation. The first half of the process, characterized by dedifferentiation of PEC, is accompanied by a marked decrease in adhesiveness of PEC to collagen type I- or type IV-coated dishes. To understand the underlying mechanisms of this change, we analyzed the expression of integrins, which are major receptors for extracellular matrix components. Northern blot analysis with cDNA probes for chicken α3, α6, α8, αv, β1 and β5 integrin mRNA showed that the genes for all these integrins are transcribed at similar levels in PEC and dedifferentiated PEC (dePEC). Further analysis of β1 integrin, which is a major component of integrin heterodimers, showed that although the protein amount of β1 integrin was not changed, its localization at focal contacts seen in PEC was lost in dePEC. When anti-β1 integrin antibody was added to the PEC culture medium, a decrease of cell-substrate adhesiveness occurred, followed by a gradual change in both morphology and gene expression patterns to ones similar to those of dePEC. These findings suggest that an appropriate distribution of β1 integrin plays an essential role in maintaining the differentiated state of PEC through cell-substrate adhesion. 相似文献
8.
Lawrence Kass 《Biotechnic & histochemistry》1995,70(5):271-274
Megakaryocytes from normal persons and from patients with immune thrombocytopenic purpura, myelodysplastic disorders, Hypersplenism, and essential thrombocythemia displayed vivid magenta metachromatic staining of the cytoplasm when stained with basic black MSP followed by brief exposure to dilute hydrochloric acid. Under the same conditions, other hematopoietic cells were completely decolorized. Acid fast metachromasia of megakaryocytes facilitates their identification, particularly in cases of small and atypical megakaryocytes found in disease states. 相似文献
9.
Durosinmi M. A. Ojo J. O. Oluwole A. F. Ononye A. F. Akanle O. A. Spyrou N. M. 《Biological trace element research》1994,(1):357-361
The concentrations of a number of elements are determined in the plasma and erythrocytes of 21 Nigerians (11 females, 10 males)
with symptomatic affective disorders (11 depressives, 10 manics) and in 40 normal controls using proton-induced X-ray emission
(PIXE) analysis. The study shows that there is significant elevation of plasma K and Zn, as well as the erythrocyte S in the
patients relative to the controls. The plasma and erythrocyte Cu, and the erythrocyte P, Ca, Fe, and Zn are significantly
lower in the patients compared to the controls. However, the plasma levels of Ca, S, Fe, and Br are similar in both the patients
and the controls. Similarly, the concentrations of K, Br, and Rb show no significant difference in the erythrocytes of patients
and controls. 相似文献
10.
Ralph A. Nixon Susan E. Lewis Marc Mercken Ram K. Sihag 《Neurochemical research》1994,19(11):1445-1453
Newly synthesized neurofilament proteins become highly phosphorylated within axons. Within 2 days after intravitreously injecting normal adult mice with [32P]orthophosphate, we observed that neurofilaments along the entire length of optic axons were radiolabeled by a soluble32P-carrier that was axonally transported faster than neurofilaments.32P-incorporation into neurofilament proteins synthesized at the time of injection was comparatively low and minimally influenced the labeling pattern along axons.32P-incorporation into axonal neurofilaments was considerably higher in the middle region of the optic axons. This characteristic non-uniform distribution of radiolabel remained nearly unchanged for at least 22 days. During this interval, less than 10% of the total32P-labeled neurofilaments redistributed from the optic nerve to the optic tract. By contrast, newly synthesized neurofilaments were selectively pulse-labeled in ganglion cell bodies by intravitreous injection of [35S]methionine and about 60% of this pool translocated by slow axoplasmic transport to the optic tract during the same time interval. These findings indicate that the steady-state or resident pool of neurofilaments in axons is not identical to the newly synthesized neurofilament pool, the major portion of which moves at the slowest rate of axoplasmic transport. Taken together with earlier studies, these results support the idea that, depending in part on their phosphorylation state, transported neurofilaments can interact for short or very long periods with a stationary but dynamic neurofilament lattice in axons.Special issue dedicated to Dr. Sidney Ochs. 相似文献