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排序方式: 共有201条查询结果,搜索用时 15 毫秒
1.
2.
Telfer JF; Thomson AJ; Cameron IT; Greer IA; Norman JE 《Human reproduction (Oxford, England)》1997,12(10):2306-2312
Superoxide, an agent which attenuates the half-life of nitric oxide, is
metabolized and synthesized by superoxide dismutase (SOD) and xanthine
oxidase, respectively. Over the last few years much work has focused on the
role of nitric oxide in human parturition. The aim of this study was to
determine whether the onset of human parturition is associated with a
change in the expression of copper/zinc superoxide dismutase (Cu/Zn SOD),
manganese superoxide dismutase (Mn SOD) or xanthine oxidase within the
uterus. Samples of myometrium, placenta, decidua and fetal membranes were
obtained from women before and after the onset of labour at term.
Immunocytochemistry was used to localize Cu/Zn SOD, Mn SOD and xanthine
oxidase and measure SOD enzyme activity. Cu/Zn and Mn SOD-like
immunoreactivity was detected in syncytiotrophoblast cells, villous stromal
cells and endothelial cells of blood vessels in the placenta. In the
myometrium Cu/Zn and Mn SOD were localized to myocytes and endothelial
cells and to some vascular smooth muscle cells. In the fetal membranes we
observed staining for Cu/Zn SOD and Mn SOD in the amnion, chorion,
extravillous trophoblast and decidua. There was no difference in SOD enzyme
activity or staining intensity for SOD between different cell types before
and during labour. Xanthine oxidase immunoreactivity was identified in each
of the tissues examined and again there was no difference in immunostaining
in tissues obtained from women delivered before or after the onset of
labour. These results show that the pregnant uterus is capable of both
synthesizing and degrading superoxide and suggest that superoxide dismutase
and xanthine oxidase may play a role in the maintenance of uterine
quiescence during pregnancy, but not in the initiation of parturition.
相似文献
3.
Endothelin receptor expression in human decidua 总被引:3,自引:1,他引:3
Kohnen G; Campbell S; Irvine GA; Church HJ; MacLachlan F; Titterington M; Cameron IT 《Molecular human reproduction》1998,4(2):185-193
The endothelins are signalling peptides that act via two receptors, ET(A)
and ET(B). In the human endometrium, endothelin receptors have been
demonstrated in glands and stroma and have been shown to vary during the
course of the menstrual cycle. The present study was undertaken to
determine whether or not expression of endothelin receptors changes during
pregnancy or after administration of exogenous progestagens. The expression
of the receptors was correlated with the appearance of basement membrane
components during decidualization of the endometrial stroma. Decidual
specimens (n = 15) were obtained during the first trimester of pregnancy
and 10 at term. Sixteen pairs of endometrial biopsies were obtained from
women with menorrhagia before and after exposure to exogenous progestagens.
A total of 15 hysterectomy specimens were used as controls for the
expression of stromal basement membrane proteins in the absence of
decidualization. Autoradiography was carried out with selective ligands for
ET(A) ([125I]-PD 151242) and ET(B) ([125I]-BQ3020). The distribution of
ligand binding was then compared with the distribution of laminin alpha2
light chain and collagen IV. ET(A), ET(B), laminin alpha2 light chain, and
collagen IV were expressed in stromal decidual cells in the first trimester
of pregnancy. ET(B) was also found on endometrial glandular epithelium.
Quantitative macro-autoradiography and multiple regression analysis
demonstrated a highly significant positive correlation (P < 0.001)
between expression of ET(B) and laminin alpha2 light chain. In the third
trimester qualitative examination suggested a reduction of ET(A) in the
stroma. Progestagen-induced decidua exhibited a similar pattern to that
found in first trimester decidua. This study has demonstrated up-regulation
of ET(B) during the progesterone- dependent process of decidualization and
suggests a paracrine or autocrine role for endothelins in the decidua.
相似文献
4.
Demchenko AP Sytnik AI 《Proceedings of the National Academy of Sciences of the United States of America》1991,88(20):9311-9314
Polar solvents are characterized by statistical distributions of solute-solvent interaction energies that result in inhomogeneous broadening of the solute electronic spectra. This allows photoselection of the high interaction energy part of the distribution by excitation at the red (long-wavelength) edge of the absorption bands. We observe that intramolecular electron transfer in the bianthryl molecule from the locally excited (LE) to the charge-transfer (CT) state, which requires solvent relaxation and does not occur in vitrified polar solutions, is dramatically facilitated in low-temperature propylene glycol glass by the red-edge excitation. This allows one to obtain spectroscopically the pure CT form and observe its dependence upon the relaxational properties of the solvent. A qualitative potential model of this effect is presented. 相似文献
5.
6.
Cytogenetic studies in non-African Burkitt lymphoma 总被引:4,自引:0,他引:4
A particular translocation between chromosomes 8 and 14 has been found repeatedly in cytogenetic studies of Burkitt lymphoma, both of African and non-African origin. We report here our findings in cytogenetic studies of direct tumor preparations from 18 non-African Burkitt lymphoma patients, 9 of whom also had cell lines available for study. A t(8;14) was found in direct tumor material in 10 of the 18 patients. Seven of the 9 cell lines had a t(8;14). A total of 15 patients had either a t(8;14) or a 14q+ present in tumor material and/or cell lines. In addition, 8 patients had a peculiar marker chromosome 1. The t(8;14) was not found in every malignant cell and, where present, it was rarely the sole karyotypic abnormality. The relationship of the t(8;14) to the evolution of the tumor is discussed. 相似文献
7.
Moskvin A. N. Platonova T. Ph. Zhilyaev S. Yu. Alekseeva O. S. Nikitina E. R. Demchenko I. T. 《Neuroscience and behavioral physiology》2020,50(4):505-510
Neuroscience and Behavioral Physiology - Respiration of hyperbaric oxygen (HBO2) suppresses the synthesis of γ-aminobutyric acid (GABA) in the brain, leading to weakening of inhibitory... 相似文献
8.
9.
Clinical and cytochemical study of the wound exudate neutrophilic granulocytes (NG) in patients with maxillofacial phlegmons treated traditionally and with leukinferon (immunomodulator) added to basic therapy demonstrated a positive clinical effect and pronounced stimulation of NG in the patients treated with leukinferon. The time course of cytochemical parameters of NG cytoplasm and chromatin activity was principally different in the two groups of patients. A new tissue index of NG was developed, giving an accurate integral picture of the total biological activity of the wound exudate NG. 相似文献
10.
The mechanism of oxygen-induced cerebral vasoconstriction has been sought for more than a century. Using genetically altered mice to enhance or disrupt extracellular superoxide dismutase (EC-SOD, SOD3), we tested the hypothesis that this enzyme plays a critical role in the physiological response to oxygen in the brain by regulating nitric oxide (NO*) availability. Cerebral blood flow responses in these genetically altered mice to changes in PO2 demonstrate that SOD3 regulates equilibrium between superoxide (*O2-) and NO*, thereby controlling vascular tone and reactivity in the brain. That SOD3 opposes inactivation of NO* is shown by absence of vasoconstriction in response to PO2 in the hyperbaric range in SOD3+/+ mice, whereas NO-dependent relaxation is attenuated in SOD3-/- mutants. Thus, EC-SOD promotes NO* vasodilation by scavenging *O2- while hyperoxia opposes NO* and promotes constriction by enhancing endogenous *O2- generation and decreasing basal vasodilator effects of NO*. 相似文献