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51.
The Northeast area of China is a cross region between East Asia and Siberia. Although five populations from this area have
been studied in maternal lineage, little is known about the genetics of other populations. In this study, forty-seven Manchu
individuals were analyzed using a mitochondrial DNA marker, and fourteen mitochondrial DNA haplogroups, the representative
haplogroups of east Eurasian, were identified. All analyses showed that Manchu were close to the neighboring populations such
as Mongolian, Korean and northern Han Chinese, and were far from the other populations who lived in the cradle of Manchu,
suggesting that the Manchu integrated gradually with natives following its southward migration. 相似文献
52.
The co-culture of the suspension cells of Taxus chinensis var. mairei and its endophytic fungi, Fusarium mairei, in a 20-L co-bioreactor was successfully established for paclitaxel production. The co-bioreactor consists of two-unit tanks
(10 L each) with a repairable separate membrane in the center, culturing Taxus suspension cells in one tank and growing fungi in another. By optimizing the co-culture conditions, there was a desirable
yield of paclitaxel in Taxus cell cultures. The Taxus cell cultures by co-culture produced 25.63 mg/L of paclitaxel within 15 days; it was equivalent to a productivity of 1.71 mg/L
per day and 38-fold higher than that by uncoupled culture (0.68 mg/L within 15 days). The optimum conditions for co-culture
in the co-bioreactor were: B5 medium, inoculating fungi when Taxus cells had grown for 5 days in the co-bioreactor, hydrophilic separate membrane in the center of the co-bioreactor, and air
flow rate of 1:0.85 v/v/m in fungus cultures. 相似文献
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56.
Mechanisms involved in agonist-induced hyperaggregability of platelets from normal pregnancy 总被引:2,自引:0,他引:2
Dr. Joen-Rong Sheu George Hsiao Wen-Yi Lin Tzeng-Fu Chen Yi-Yi Chien Chien-Huang Lin Chiu-Ruey Tzeng 《Journal of biomedical science》2002,9(1):17-25
There is substantial evidence of increased platelet reactivity in vivo and in vitro during pregnancy. Platelet activation occurs in pregnancy with a risk of the development of preeclampsia. In this study, platelet behavior was studied during 28-40 weeks of gestation in a group of women who remained normotensive and a group of nonpregnant female controls. Platelet aggregation and ATP release stimulated by agonists (i.e. collagen and adenosine 5'-diphosphate) were markedly enhanced in washed platelets from pregnant subjects. Furthermore, the collagen-evoked increase in intracellular Ca(2+) ([Ca(2+)](i)) mobilization in fura-2-AM-loaded platelets was also enhanced in pregnant subjects. Moreover, the binding activity of fluorescein isothiocyanate-triflavin toward the platelet glycoprotein IIb/IIIa complex did not significantly differ between the nonpregnant and pregnant groups. In addition, the amount of thromboxane A(2) (TxA(2)) formation from pregnant subjects was significantly greater than that from nonpregnant subjects in both resting and collagen-activated platelets. On the other hand, prostaglandin E(2) formation in the presence of imidazole in either resting or arachidonic acid (100 microM)-treated platelets did not significantly differ between these two groups. The levels of cyclic AMP formation in both resting and prostaglandin E(1) (10 microM)-treated platelets from pregnant subjects were significantly lower than those in nonpregnant subjects. Nitric oxide production was measured by a chemiluminescence detection method in this study. The extent of nitrate production in either resting or collagen-stimulated platelets from pregnant subjects did not significantly differ from that of platelets from the nonpregnant group. We conclude that the agonist-induced hyperaggregability of platelets from normal pregnancy may be due, at least partly, to an increase in TxA(2) formation and a lowering of the level of cyclic AMP formation, which leads to increased [Ca(2+)](i) mobilization and finally to enhanced platelet aggregation and ATP release. 相似文献
57.
Wen-Yi Hung Chew-Wun Wu Pen-Hui Yin Chun-Ju Chang Anna Fen-Yau Li Chin-Wen Chi Yau-Huei Wei Hsin-Chen Lee 《Biochimica et Biophysica Acta (BBA)/General Subjects》2010
Background
Somatic mutation in mitochondrial DNA (mtDNA) has been proposed to contribute to initiation and progression of human cancer. In our previous study, high frequency of somatic mutations was found in the D-loop region of mtDNA of gastric cancers. However, it is unclear whether somatic mutations occur in the coding region of mtDNA of gastric cancers.Methods
Using DNA sequencing, we studied 31 gastric cancer specimens and corresponding non-cancerous stomach tissues. Moreover, a human gastric cancer SC-M1 cell line was treated with oligomycin to induce mitochondrial dysfunction. Cisplatin sensitivity and cell migration were analyzed.Results
We identified eight somatic mutations in the coding region of mtDNAs of seven gastric cancer samples (7/31, 22.6%). Patients with somatic mutations in the entire mtDNA of gastric cancers did not show significant association with their clinicopathologic features. Among the eight somatic mutations, five point mutations (G3697A, G4996A, G9986A, C12405T and T13015C) are homoplasmic and three mutations (5895delC, 7472insC and 12418insA) are heteroplasmic. Four (4/8, 50%) of these somatic mutations result in amino acid substitutions in the highly conserved regions of mtDNA, which potentially lead to mitochondrial dysfunction. In addition, in vitro experiments in SC-M1 cells revealed that oligomycin-induced mitochondrial dysfunction promoted resistance to cisplatin and enhanced cell migration. N-acetyl cysteine was effective in the prevention of the oligomycin-enhanced migration, which suggests that reactive oxygen species generated by defective mitochondria may be involved in the enhanced migration of SC-M1 cells.General Significance
Our results suggest that somatic mtDNA mutations and mitochondrial dysfunction may play an important role in the malignant progression of gastric cancer. 相似文献58.
Alice Shau Ping Ma Martha E. Bystol Andrew Tranvan 《In vitro cellular & developmental biology. Animal》1994,30(5):329-335
Summary In our preliminary subcellular localization experiment we demonstrated that annexin II co-localized with submembranous actin
in subpopulations of both cultured fibroblasts and keratinocytes. To investigate the physical interaction between annexin
II and actin at the cell periphery, in vitro reconstitution experiments were carried out with keratins used as a control.
Annexin II, isolated by immunoaffinity column chromatography, was found to exist as globular structures measuring 10 to 25
nm in diameter by rotary shadowing, similar to a previous report. We believe that these structures represent its polymeric
forms. By negative staining, monomeric annexin II was detectable as tapered rods, measuring 6 nm in length and 1 to 2 nm in
diameter. When annexin II was mixed with actin in 3 mM piperazine-N, N-bis-2-ethanesulfonic acid (PIPES) buffer with 10 mM NaCl2, 2 mM MgCl2 and 0.1 mM CaCl2, thick twisting actin bundles formed, confirming previous reports. This bundling was much reduced when calcium was removed.
In the presence of 5 mM ethylenediamine tetra-acetic acid (EDTA) in 5 mM tris, pH 7.2, keratins were found to form a network of filaments, which began to disassemble when the chelator was removed
and became fragmented when 0.1 mM CaCl2 was added. Keratins under the same conditions did not fragment when annexin II was present. These results suggest that annexin
II, in conjunction with Ca2+, may be involved in a flexible system accommodating changes in the membrane cytoskeletal framework at the cell periphery
in keratinocytes. 相似文献
59.
Thymocyte-derived lymphokine-activated killer (LAK) cells were used as a model for the study of the cytokine driven development of cytotoxicity. These cells are devoid of initial cytotoxic activity but upon culture in IL-2 they develop into cytotoxic effectors. The parameters of the response of thymocytes to IL-6 are similar to that of PBL in that IL-6, at concentrations as low as 1 mu/ml, increases cytotoxicity of thymocyte-LAK cells when generated in low doses (25-50 mu/ml) of IL-2. IL-6-enhanced thymocyte-LAK cytotoxicity is observed when tested against both NK-resistant and NK-sensitive tumor cell lines. IL-6 alone does not induce any cytotoxicity from thymocytes nor does IL-6 change the time course of thymocyte-LAK cell generation in IL-2 culture. IL-6 does not affect DNA synthesis, total cell number, proportion of CD56+ cells, or the expression of IL-2R (both P55 and P75 glycoproteins) in IL-2-cultured thymocytes. Instead, IL-6 used to treat mature thymocyte-LAK effector cells for as little as 1 hr prior to 51Cr-release assay increases LAK cytotoxicity. This enhancement is abrogated by pretreatment of effector cells with cycloheximide, suggesting that protein synthesis is required for IL-6 to enhance LAK cell activity. The precursor phenotypes of IL-6-responsive thymocyte-LAK cells are CD3-/CD5-. The effector phenotypes of IL-6-enhanced thymocyte-LAK cells are CD5-/CD56+. Thus, IL-6 depends on synthesis of rapid-turnover proteins to act on mature CD56+/CD5- LAK cells to increase their cytotoxic function. 相似文献
60.
Jo-Ping Lee Chung-Li Wang Yio-Wha Shau Shwu-Fen Wang 《Journal of electromyography and kinesiology》2009,19(3):391-397
Deep muscle training has become the focus of research and exercise for patients with chronic neck pain. The objective of this in vivo study was to establish a non-invasive assessment tool for the activation of deep cervical muscles. The pattern of the change in the thickness of the cervical multifidus is described with a mathematical equation and used to compare the changes among different levels of resistance (0%, 25%, 50%, 75%, and 100%) and at different cervical levels (fourth, fifth, and sixth cervical (C4, C5, and C6) vertebrae). Twenty asymptomatic subjects (five women and 15 men; 24.3 ± 4.7 years old) were recruited for this experiment. Ultrasonography (US) with synchronized force recording was used to measure the thickness of the cervical multifidus during progressive isometric extension against resistance. Linear and quadratic models were used to estimate the patterns of change in the thickness of cervical multifidus in relation to force. Two-way analysis of variance with repeated measurement and post hoc analysis were used to investigate the differences in thickness. The change in thickness and force was better fitted by quadratic model (y = ax2 + bx + c) than by the linear model. The thickness at 50% of maximum contraction was significantly increased compared with that at 25% of maximum contraction. This quantitative non-invasive measurement may provide an assessment tool for further investigation for the physiological function of the deep muscles. Further research is required to investigate whether the change of thickness was predominately determined by the recruitment of muscle fibers or the extensibility of non-contractile tissues. 相似文献