首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   247篇
  免费   24篇
  国内免费   48篇
儿科学   13篇
妇产科学   2篇
基础医学   38篇
口腔科学   3篇
临床医学   47篇
内科学   65篇
皮肤病学   2篇
神经病学   6篇
特种医学   51篇
外科学   13篇
综合类   20篇
预防医学   13篇
眼科学   2篇
药学   37篇
中国医学   1篇
肿瘤学   6篇
  2020年   3篇
  2019年   4篇
  2018年   6篇
  2015年   6篇
  2014年   6篇
  2013年   10篇
  2011年   4篇
  2010年   11篇
  2009年   9篇
  2008年   5篇
  2007年   34篇
  2006年   6篇
  2005年   9篇
  2004年   5篇
  2003年   2篇
  2002年   5篇
  2001年   6篇
  2000年   7篇
  1999年   9篇
  1998年   10篇
  1997年   10篇
  1996年   16篇
  1995年   9篇
  1994年   8篇
  1993年   15篇
  1992年   6篇
  1991年   5篇
  1990年   10篇
  1989年   6篇
  1988年   9篇
  1987年   6篇
  1986年   5篇
  1985年   2篇
  1984年   4篇
  1982年   9篇
  1981年   4篇
  1980年   4篇
  1978年   3篇
  1977年   5篇
  1976年   3篇
  1975年   2篇
  1974年   2篇
  1972年   1篇
  1971年   4篇
  1970年   2篇
  1968年   2篇
  1966年   2篇
  1965年   1篇
  1913年   1篇
  1911年   1篇
排序方式: 共有319条查询结果,搜索用时 15 毫秒
51.

Background  

This study evaluates the existence of numerical alterations of chromosome 17 and TP53 gene deletion in gastric adenocarcinoma. The p53 protein expression was also evaluated, as well as, possible associations with clinicopathological characteristics.  相似文献   
52.
We applied the radioactive microsphere method to follow the magnitude and time course (0 to 96 hours) of blood flow changes during development and recovery from anemia in awake rats. Blood flow was also monitored during a 96-hour period after polycythemia was induced (erythropoietin administered subcutaneously [SC]). The possible influence of innervation was also examined. After a blood loss of approximately 50% (hypovolemia), blood flow to the femoral marrow tripled within 12 hours and remained elevated for the entire 96-hour period. The relative increase in blood flow to the femoral bone was even greater. Similar findings were obtained in rats with phenylhydrazine (PHZ) hemolytic anemia (normovolemia). Denervation had no detectable effect on the increased blood flow to either marrow or bone. The augmented blood flow during hemolytic anemia was accompanied by a doubling of the oxygen consumption rate by the marrow, while the glucose uptake was not detectably altered. Erythropoietin supplements (3 x 1,000 IU/kg, SC, 6-hour intervals) increased blood flow to the marrow by approximately 25% after 48 hours, and at 72 hours the blood flow had reached a value twice that obtained under control conditions. These results indicate that blood flow to bone marrow is highly variable and hormonally and/or locally regulated. This may have practical consequences for marrow transplantation technology and for administration of drug therapy to patients with insufficient bone marrow hematopoiesis.  相似文献   
53.
Oxidative metabolism of the human eosinophil   总被引:14,自引:1,他引:14  
We have compared the oxidative metabolism of human eosinophils (80%-90% purity) to that of neutrophils. Hexose monophosphate (HMP) shunt activity of eosinophils was higher than that of neutrophils under either resting or phagocytizing conditions. Eosinophil HMP shunt activity also was stimulated by phorbol myristate acetate, a membrane- active agent. Eosinophils showed a marked incorporation of 125I into trichloroacetic acid-insoluble material under resting conditions, which increased markedly during phagocytosis. Eosinophils likewise showed a greater reduction of nitroblue tetrazolium dye during phagocytosis than did neutrophils. Measurement of other parameters of oxidative metabolism indicated that eosinophils generated superoxide anion following phagocytosis and also elicited a burst of chemiluminescence similar to that observed during phagocytosis by neutrophils. Measurement of NADPH oxidase activity demonstrated that this enzyme was 3-6 times more active in fractions isolated from eosinophils than in corresponding fractions isolated from neutrophils; this was observed over a range of substrate concentrations. The eosinophil enzyme sedimented differently than the neutrophil enzyme with differential centrifugation; neither showed sedimentation characteristics of peroxidase. These data indicate that eosinophils possess a similar, although in some ways more potent, oxidative burst than neutrophils and are consistent with a role for NADPH oxidase in the initiation of that burst.  相似文献   
54.
55.
56.
57.
Discomfort and factual recollection in intensive care unit patients   总被引:2,自引:0,他引:2  

Introduction

A stay in the intensive care unit (ICU), although potentially life-saving, may cause considerable discomfort to patients. However, retrospective assessment of discomfort is difficult because recollection of stressful events may be impaired by sedation and severe illness during the ICU stay. This study addresses the following questions. What is the incidence of discomfort reported by patients recently discharged from an ICU? What were the sources of discomfort reported? What was the degree of factual recollection during patients' stay in the ICU? Finally, was discomfort reported more often in patients with good factual recollection?

Methods

All ICU patients older than 18 years who had needed prolonged (>24 hour) admission with tracheal intubation and mechanical ventilation were consecutively included. Within three days after discharge from the ICU, a structured, in-person interview was conducted with each individual patient. All patients were asked to complete a questionnaire consisting of 14 questions specifically concerning the environment of the ICU they had stayed in. Furthermore, they were asked whether they remembered any discomfort during their stay; if they did then they were asked to specify which sources of discomfort they could recall. A reference group of surgical ward patients, matched by sex and age to the ICU group, was studied to validate the questionnaire.

Results

A total of 125 patients discharged from the ICU were included in this study. Data for 123 ICU patients and 48 surgical ward patients were analyzed. The prevalence of recollection of any type of discomfort in the ICU patients was 54% (n = 66). These 66 patients were asked to identify the sources of discomfort, and presence of an endotracheal tube, hallucinations and medical activities were identified as such sources. The median (min–max) score for factual recollection in the ICU patients was 15 (0–28). The median (min–max) score for factual recollection in the reference group was 25 (19–28). Analysis revealed that discomfort was positively related to factual recollection (odds ratio 1.1; P < 0.001), especially discomfort caused by the presence of an endotracheal tube, medical activities and noise. Hallucinations were reported more often with increasing age. Pain as a source of discomfort was predominantly reported by younger patients.

Conclusion

Among postdischarge ICU patients, 54% recalled discomfort. However, memory was often impaired: the median factual recollection score of ICU patients was significantly lower than that of matched control patients. The presence of an endotracheal tube, hallucinations and medical activities were most frequently reported as sources of discomfort. Patients with a higher factual recollection score were at greater risk for remembering the stressful presence of an endotracheal tube, medical activities and noise. Younger patients were more likely to report pain as a source of discomfort.
  相似文献   
58.
用[3H]TdR参入法检测小鼠脾细胞增殖能力及产生集落刺激因子(colony stimulating factor. CSF)含量.证明商陆多糖Ⅱ(PAP-Ⅱ)在31~500 μg·m-1范围内显著促进小鼠稗细胞增殖。PAP-Ⅱ,31~125 μg·ml-1可剂量依赖性地促进Con A(1,2.8μg·ml-1),LPS(3,10,30 μg·ml-1)诱导的淋巴细胞细咆增殖,随着PAP-Ⅱ剂量加大,对丝裂原诱导的淋巴细胞增殖反呈抑制作用。PAP-Ⅱ。10~500μg·ml-1呈剂量及时间依赖性地促进脾细胞产生CSF,其最适剂量为100 μg·ml-1。最佳时间为5 d,提示PAP-Ⅱ能增强免疫及促进造血功能。  相似文献   
59.
Endostatin, the 20-kDa C-terminal fragment of collagen XVIII, has previously been shown to inhibit growth and induce regression of different experimental tumors in rodents. In this study, we show that recombinant murine and human endostatin, produced in 293 EBNA cells and yeast, respectively, inhibit ectotopic as well as orthotopic growing BT4Cn gliosarcomas in BD-IX rats. In rats in which s.c. gliomas were grown for a total of 29 days, systemic treatment with recombinant murine endostatin induced about 50% reduction of intratumoral blood flow and tumor size after only 10 days of therapy. In contrast, the blood flow to irrelevant organs was unaffected by endostatin, indicating its specificity of action. Tumors were not observed to increase in size or regrow after cessation of therapy. Furthermore, endostatin-treated rats with i.c. tumors had significantly longer survival time than did untreated controls. In the treated rats, endostatin therapy resulted in a reduced tumor blood vessel volume and an increased tumor cell density with an increased apoptotic index within a given tumor volume, as verified by flow cytometry and by staining with deoxynucleotidyltransferase-mediated dUTP nick-end labeling. This work verifies the general anti-angiogenic and antitumor effects of endostatin and indicates that the protein may also be considered as a treatment strategy for malignant brain tumors.  相似文献   
60.
商陆多糖Ⅰ(PAP-I),0.3~3μg·ml-1和小鼠脾细胞培养3~5d可显著增强其杀伤P815肿瘤细胞活性及IL-2(250~500IU·ml-1)诱导的LAK细胞活性,最适浓度为1μg·ml-1。PAP-I及IL-2和脾细胞培养的上清液对P815肿瘤细胞无细胞毒作用,但能增强脾细胞及LAK细胞杀瘤活性。PAP-I,5,10及50mg·kg-1,ip可增强脾细胞杀伤P815和L929细胞的活性及IL-2诱导的LAK细胞活性。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号