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Dipeptidyl peptidase IV (DPPIV) is a transmembrane serine protease which is involved in the process of tumor invasion and development of metastases in human cancers. The aim of this study was to investigate the expression of DPPIV in cancer and stromal cells of both esophageal adenocarcinoma and squamous cell carcinoma (SCC). Tissue material from 159 patients was analyzed using immunohistochemistry. Western blotting was performed on cell lines and fresh frozen tissue sections. Results were compared with clinicopathological features. Evaluation of the immunohistochemical findings revealed significant differences between DPPIV expression in carcinoma cells and stromal cells, depending on the histological tumor type. A significantly higher level of DPPIV was found in adenocarcinomas compared to SCCs while no DPPIV was detected in normal esophageal epithelium. Overexpression of DPPIV in patients with adenocarcinoma was additionally associated with distant metastases. Thus, differences of DPPIV level in esophageal carcinomas compared with normal epithelium showed that esophageal malignancies were associated with an increased amount of cell surface‐bound DPPIV. Radiotherapy in patients had no impact on DPPIV expression in analyzed tissue samples. There was no correlation between DPPIV expression in cancer or stromal cells and survival of the patients.  相似文献   
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Powerful new ideas about the teaching of reading are sweeping through the ranks of professional reading specialists, elementary reading teachers and teacher educators. Are classroom teachers prepared to assume new roles crucial to the implementation of these ideas? For the past three years, the Eastern Washington University Department of Education has conducted research which casts cautious doubt, not on teachers' capabilities, but on teachers' preparation in the vita! area of reading comprehension: instruction. The results of this research indicate that few practicing teachers can discriminate comprehension: instruction from other activities related to the teaching of reading comprehension. This article details research methods, findings and implications.  相似文献   
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体外膜肺氧合技术支持治疗期间患者血乳酸浓度及其预后   总被引:2,自引:1,他引:2  
目的:探讨体外膜肺氧合支持治疗患者血乳酸浓度的变化和预后。方法:于2004-12/2006-09在中国医学科学院阜外心血管病医院因脱离体外循环困难的心脏外科术后患者、扩张性心肌病和冠状动脉粥样硬化性心脏病发生心源性休克的患者共40例进行了体外膜肺氧合支持治疗,按年龄和存活预后分为4组:成人存活组、成人死亡组、儿童存活组、儿童死亡组。分析4组的治疗效果,分别抽取各组患者体外膜肺氧合建立时、体外膜肺氧合运转6h、运转中间时点、停机前6h、停机时的血乳酸浓度。结果:①体外膜肺氧合支持治疗患者40例,成人组26例,20例脱机,16例生存,10例死亡,脱机率76.9%,生存率61.5%;儿童组14例,7例脱机,5例生存,9例死亡,脱机率50.0%,生存率35.0%。②成人或儿童存活组的乳酸浓度都与死亡组有明显差别,存活组血乳酸浓度明显低于死亡组,其中建立和运转6h、中间时点的差异有显著性意义(P<0.05),其余2个时点的差异有非常显著性意义(P<0.001)。组内与建立时比较,中间时点、停止前6h、停止时差异均有显著性意义(P<0.001),血乳酸浓度逐渐降低。结论:经体外膜肺氧合支持治疗的患者,血乳酸浓度明显下降,脱机时血乳酸仍高的患者预后不良。  相似文献   
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Aldosterone stimulates not only Na+ absorption but also urinary acidification. In this investigation the effects of aldosterone on H+ transport are examined in vitro in turtle bladder, a urinary membrane in which several of the factors controlling H+ transport have been defined. H+ transport was increased in bladder halves exposed to aldosterone compared to control halves. Stimulation of H+ secretion was observed as early as 1 h after addition of aldosterone and occurred before that of Na+ transport. In bladders depleted of endogenous substrate addition of glucose increased H+ transport more in aldosterone-treated halves (10.0+/-1.3 nmol/min) than in control halves (6.8+/-2.3). Addition of pyruvate failed to increase H+ transport (--0.3+/-0.7) in control halves but caused significant increments (2.4+/-0.5) in aldosterone-treated halves. In aldosterone-treated bladders glucose caused larger increments (16.5+/-2.7) in H+ transport than pyruvate (9.3+/-2.0) when halves of the same bladders were compared. Na+ transport, however, was equally increased by the two substrates. Despite the differences in time course and substrate requirements between the stimulation of H+ and Na+ transport, both increases were abolished by actinomycin-D. To examine the effect of aldosterone on the force of the H+ pump, protonmotive force, the pH gradient that would nullify the transport rate was determined with and without aldosterone. Aldosterone did not alter protonmotive force but significantly increased the slope of the H+ transport rate on the applied pH gradient. It is concluded that aldosterone stimulates H+ transport independently of Na+ transport. It increases the responsiveness of the transport rate to glucose and to a lesser extent pyruvate, an effect probably secondary to the increased transport rate. Equivalent circuit analysis indicates that aldosterone facilitates the flow of protons through the active transport pathway but does not increase the force of the pump.  相似文献   
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Oxidative stress is intimately involved in alcoholic cardiomyopathy. Catalase is responsible for detoxification of hydrogen peroxide (H(2)O(2)) and may interfere with ethanol-induced cardiac toxicity. To test this hypothesis, a transgenic mouse line was produced to overexpress catalase (~50-fold) in the heart, ranging from sarcoplasm, the nucleus and peroxisomes within myocytes. Mechanical and intracellular Ca(2+) properties were evaluated in ventricular myocytes from catalase transgenic (CAT) and wild-type FVB mice. Protein abundance of sarco (endo) plasmic reticulum Ca(2+)-ATPase (SERCA), phospholamban (PLB), Na(+)/Ca(2+) exchanger (NCX), dihydropyridine Ca(2+) receptor (DHPR), ryanodine receptor (RyR), Akt and phosphorylated Akt (pAkt) were measured by western blot. CAT itself did not alter body and organ weights, as well as myocyte contractile properties. Acute exposure of ethanol elicited a concentration-dependent depression in cell shortening and intracellular Ca(2+) in FVB mice with maximal inhibitions of 65.4% and 35.8%, respectively. The ethanol-induced cardiac depression was significantly attenuated in myocytes from CAT with maximal inhibitions of 42.4% and 27.3%. CAT also abrogated the ethanol-induced inhibition of maximal velocity of shortening/relengthening, prolongation of relengthening duration and intracellular Ca(2+) clearing time. Cell shortening at different extracellular Ca(2+) revealed stronger myocyte-shortening amplitude under lower (0.5 mM) Ca(2+) in CAT mice. Protein expression of NCX, RyR, Akt and pAkt were elevated in myocytes from CAT mice, while those of SERCA, PLB and DHPR were not affected. In conclusion, our data suggest that catalase overexpression may protect cardiac myocytes from ethanol-induced contractile defect, partially through improved intracellular Ca(2+) handling and Akt signaling.  相似文献   
19.
Catalytic methane steam reforming was conducted at low temperature using a Pd catalyst supported on Ce1−xMxO2 (x = 0 or 0.1, M = Ca, Ba, La, Y or Al) oxides with or without an electric field (EF). The effects of the catalyst support on catalytic activity and surface proton hopping were investigated. Results show that Pd/Al-CeO2 (Pd/Ce0.9Al0.1O2) showed higher activity than Pd/CeO2 with EF, although their activity was identical without EF. Thermogravimetry revealed a larger amount of H2O adsorbed onto Pd/Al-CeO2 than onto Pd/CeO2, so Al doping to CeO2 contributes to greater H2O adsorption. Furthermore, electrochemical conduction measurements of Pd/Al-CeO2 revealed a larger contribution of surface proton hopping than that for Pd/CeO2. This promotes the surface proton conductivity and catalytic activity during EF application.

Temperature dependence of electron/ion conductivity of Pd/CeO2 and Pd/Al-CeO2 under wet conditions with application of an electric field.  相似文献   
20.
Fine-root production and turnover are important regulators of the biogeochemical cycles of ecosystems and key components of their response to global change. We present a nearly continuous 6-year record of fine-root production and mortality from minirhizotron analysis of a closed-canopy, deciduous sweetgum forest in a free-air CO(2) enrichment experiment. Annual production of fine roots was more than doubled in plots with 550 ppm CO(2) compared with plots in ambient air. This response was the primary component of the sustained 22% increase in net primary productivity. Annual fine-root mortality matched annual production, and the mean residence time of roots was not altered by elevated CO(2), but peak fine-root standing crop in midsummer was significantly higher in CO(2)-enriched plots, especially deeper in the soil profile. The preferential allocation of additional carbon to fine roots, which have a fast turnover rate in this species, rather than to stemwood reduces the possibility of long-term enhancement by elevated CO(2) of carbon sequestration in biomass. However, sequestration of some of the fine-root carbon in soil pools is not precluded, and there may be other benefits to the tree from a seasonally larger and deeper fine-root system. Root-system dynamics can explain differences among ecosystems in their response to elevated atmospheric CO(2); hence, accurate assessments of carbon flux and storage in forests in a globally changing atmosphere must account for this unseen and difficult-to-measure component.  相似文献   
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