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71.
Cultured human and rat tooth papilla cells induce hair follicle regeneration and fiber growth 总被引:3,自引:0,他引:3
The mesenchymal-epithelial interactions that characterize the early stages of tooth and hair follicle morphogenesis share certain similarities, and there is increasing evidence that mesenchymal cells derived from both mature structures retain interactive and stem cell-like properties. This study aimed to gauge the cross-appendage inductive capabilities of cultured tooth dental papilla (or pulp) cells from different species and ages of donor. Adult human and juvenile rat tooth papilla cells were implanted into surgically inactivated hair follicles within two different microenvironments. The human cells interacted with follicle epithelium to regenerate new end bulbs and create multiple differentiated hair fibers. Rodent tooth dental cells also induced new epithelial matrix structures and stimulated de novo hair formation. However, in many instances they also elicited mineralization and bone formation, a phenomenon that appeared to relate to their donor's age; the type of tooth of origin; and the host environment. Taken together, this study reveals that cultured dental papilla cells from postnatal mammals (adult, juvenile, and newborn) retain inductive molecular signals that must be common to both hair and teeth follicles. It highlights the stem cell-like qualities and morphogenetic abilities of tooth and hair follicle cells from mature humans, and their capacity for cross-appendage and interspecies communication and interaction. Besides the developmental implications, the present findings have relevance for stem cell biology, hair growth, tissue repair, and other biotechnologies. Moreover, the critical importance of considering the local microenvironment in which different cells/tissues are naturally or experimentally engineered is firmly demonstrated. 相似文献
72.
Alibardi L 《Journal of morphology》2004,261(3):345-363
The fine structure of hairs in the most ancient extant mammals, the monotremes, is not known. The present study analyzes the ultrastructure and immunocytochemistry for keratins, trichohyalin, and transglutaminase in monotreme hairs and compares their distribution with that present in hairs of the other mammals. The overall ultrastructure of the hair and the distribution of keratins is similar to that of marsupial and placental hairs. Acidic and basic keratins mostly localize in the outer root sheath. The inner root sheath (IRS) comprises 4-8 cell layers in most hairs and forms a tile-like sheath around the hair shaft. No cytological distinction between the Henle and Huxley layers is seen as cells become cornified about at the same time. Externally to the last cornified IRS cells (homologous to the Henle layer), the companion layer contains numerous bundles of keratin. Occasionally, some granules in the companion layer show immunoreactivity for the trichohyalin antibody. This further suggests that the IRS in monotremes is ill-defined, as the companion layer of placental hairs studied so far does not express trichohyalin. A cross-reactivity with an antibody against sheep trichohyalin is present in the IRS of monotremes, suggesting conserved epitopes across mammalian trichohyalin. Trichohyalin granules in the IRS consist of a framework of immunolabeled coarse filaments of 10-12 nm. The latter assume a parallel orientation and lose the immunoreactivity in fully cornified cells. Transglutaminase immunolabeling is diffuse among trichohyalin granules and among the parallel 10-12 nm filaments of maturing inner root cells. Transglutaminase is present where its substrate, trichohyalin, is modified as matrix protein. Cornification of IRS is different from that of hair fiber cuticle and from that of the cornified layer of the epidermis above the follicle. The different consistency among cuticle, IRS, and corneous layer of the epidermis determines separation between hair fiber, IRS, and epidermis. This allows the hair to exit on the epidermal surface after shedding from the IRS and epidermis. Based on comparative studies of reptilian and mammalian skin, a speculative hypothesis on the evolution of the IRS and hairs from the skin of synapsid reptiles is presented. 相似文献
73.
74.
A liquid chromatography with an electrochemical detector method has been developed for the quantitative measurement for three diamine derivatives (p-phenylenediamine, N,N(')-p-phenylenebisacetamide, and 4-aminoacetanilide) in human urine and rabbit blood, urine, and feces. The detection cell consisted of a glassy carbon electrochemical signal obtained with a supporting electrolyte containing 20% methanol-5mM octylammonium orthophosphate (pH 6.30) as the mobile phase. A comparison of the results obtained from HPLC-UV shows agreement. 相似文献
75.
Zinc deficiency is a health problem in many communities especially among adolescents because of pubertal growth sprout. This
investigation was carried out to determine the epidemiology of zinc deficiency in junior high school students in Tehran City
in 1997. This cross-sectional study was performed on 881 students (452 males and 429 females) with the mean age of 13.2±1.0
yr, who were selected by multistage random sampling method. Plasma, erythrocyte, and hair zinc levels were assayed by flame
atomic absorption spectrophotometry. Anthropometric and demographic characteristics were measured and recorded on a questionnaire.
Dietary intakes were evaluated by a 24-h recall method. Zinc deficiency was defined as having at least two indices from indices
of erythrocyte, plasma, and hair zinc below 10 μg/mL, 100 μg/dL, and 125 μg/g of hair, respectively.
The results showed that zinc deficiency prevalence was 31.1% (confidence interval: 28–34.4%). Zinc deficiency was 65%, 49%,
and 1.3% based on plasma, erythrocyte, and hair zinc levels, respectively. The mean ± SD for plasma, erythrocyte, and hair
zinc concentration, height-for-age, as well as weight-for-age Z scores were 95.2±17.7 μg/dL, 10.3±2.3 μg/mL, 239.4±54.4 μg/g,
−0.40±0.92, and 0.12±0.91, respectively. As for dietary intake compared with the RDA, 50% of the subjects consumed less than
50% of their requirement for zinc RDA based on a 24-h dietary recall. Zinc intake in subjects was 7.5±3.7 μg, that in boys
was higher than in girls. Correlation coefficients between zinc status indices were very weak. There was neither a linear
nor nonlinear relationship between biochemical parameters and nutritional zinc intake. It is concluded that almost one-third
to one-half of the subjects would be considered zinc deficient. 相似文献
76.
Validity of hair mineral testing 总被引:1,自引:0,他引:1
Shamberger RJ 《Biological trace element research》2002,87(1-3):1-28
The variance of testing was compared between the College of American Pathologists clinical survey and that of a recent review
about hair mineral testing. The review suggested that the accuracy of hair mineral testing was unreliable. In general, there
was a greater range of variance in the College of American Pathologists testing results. These latter results are based on
laboratory testing and are used as a “yardstick” to determine if a laboratory passes or fails that analyte and are considered
a “gold standard.” An extract, which resulted from a method that avoided the washing step, was compared among five laboratories.
Very good precision resulted, indicating that the varied washing steps used by the laboratories in a recent review were probably
the source of much variance.
Analysis of hair analysis seemed to yield important information in several historical or forensic cases involving Ludwig von
Beethoven, Napoleon Bonaparte, ex-US-presidents Zachary Taylor and Andrew Jackson, and Charles Hall, an Arctic explorer.
Several elements that were reviewed, including arsenic, cadmium, cobalt, germanium, lead, lithium, manganese, mercury, nickel,
and thallium, showed relationships between body burden, dosage, and exposure or toxicity. Evidence of toxicity could not be
found by measuring hair aluminum or vanadium. Chromium, selenium, and zinc seemed to have nutritional value. Ratios of hair
elements with clinical importance could not be found. 相似文献
77.
The aim of this study was to (1) estimate the concentration of selenium in the plasma of 146 residents (65 men and 81 women)
and in the hair of 34 persons from the Gdańsk region in northern Poland, aged 19–70 and (2) compare the obtained results with
data corresponding to healthy populations living in different European countries. Selenium in plasma was determined by atomic
absorption spectrometry using the hydride generation method. The mean selenium concentration in plasma of the investigated
persons was 73.3 ± 14.1 μg/L, 76.7 ± 13.2 μg/L in men, and 70.4 ± 14.7 μg/L in women. No age — dependent differences in plasma
selenium were found in the investigated population. In 20% of the investigated persons, the selenium level in plasma was lower
than 60 μg/L. The mean selenium concentration in hair was 0.30 ± 0.11 μg/g. A positive, statistically significant correlation
between selenium concentrations in the plasma and hair of the investigated persons was found. The obtained results indicate
that the selenium level in significant part of this population is suboptimal and should be elevated by supplementation with
this element. 相似文献
78.
79.
Summary. The localization of the actin-monomer-binding protein profilin during the cell cycle of living Tradescantia virginiana stamen hair cells has been studied by microinjection of a fluorescently labeled analog of the protein. In contrast to previously published studies performed on chemically fixed animal cells, we do not find a specific colocalization of profilin with actin filament arrays. Our results show that, besides a general cytoplasmic distribution, profilin specifically accumulates in the nucleus in interphase and prophase cells. This nuclear localization was confirmed by means of electron microscopic immunolocalization of endogenous profilin (in Gibasis scheldiana stamen hair cells). During mitosis, as the nuclear envelope and nuclear matrix break down at the onset of prometaphase, the nuclear profilin redistributes equally into the accessible volume (cytosol) of the cell. During metaphase and anaphase no specific localization of profilin can be observed associated with the mitotic apparatus. However, during telophase, as nuclear envelopes and nuclear matrices re-form and the sister chromatids start to decondense, a subset of the microinjected profilin again localizes to the nucleus. No accumulation of profilin could be observed in the phragmoplast, where a distinct array of actin filaments exists. The function of profilin in the nucleus remains unclear.Correspondence and reprints: Department of Biology, 221 Morrill Science Center II, University of Massachusetts, Amherst, MA 01003, U.S.A.Received September 30, 2002; accepted February 12, 2003
Published online September 23, 2003 相似文献
80.
Summary. In root hair cells of Limnobium stoloniferum, transvacuolar strands disperse and cytoplasmic spherical bodies (CSBs) emerge upon treatment with a protein phosphatase
inhibitor, calyculin A (CA), whose effects were previously shown to be canceled by simultaneous treatment of the cells with
a nonselective protein kinase inhibitor, K-252a. CSB formation is also suppressed by latrunculin B (LB) or cytochalasin D,
actin filament depolymerization drugs, or 2,3-butanedione monoxime, an inhibitor of myosin activity. To confirm the involvement
of myosin activity in CSB formation induced by CA, we examined the effect of an inhibitor of energy metabolism, NaN3, on CSB formation in root hair cells pretreated simultaneously with CA and LB. In the presence of CA-LB, CSB formation was
suppressed due to the depolymerization of actin filaments. When these drugs were removed, the actin filaments recovered and
CSBs emerged even in the presence of K-252a. These results indicated that the phosphorylation level in the cells is elevated
during the CA-LB treatment and that a phosphorylation level sufficient for the CSB formation was sustained even after CA removal.
On the other hand, CSB formation after simultaneous treatment with CA and LB was significantly suppressed in the presence
of NaN3. In such cells, actin filament bundles recovered, although their organization was random. The present and previous results
suggested that myosin activity is necessary for CSB formation induced by CA, and that myosin regulated by phosphorylation-dephosphorylation
is implicated in the organization of the actin cytoskeleton in root hair cells.
Received June 26, 2002; accepted October 18, 2002; published online April 2, 2003
RID="*"
ID="*" Correspondence and reprints: Department of Life Science, Graduate School of Science, Himeji Institute of Technology,
Harima Science Park City, Hyogo 678-1297, Japan. 相似文献