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   124篇
  免费   7篇
儿科学   6篇
妇产科学   2篇
基础医学   21篇
口腔科学   4篇
临床医学   18篇
内科学   16篇
神经病学   5篇
特种医学   8篇
外科学   15篇
综合类   3篇
预防医学   16篇
眼科学   1篇
药学   8篇
肿瘤学   8篇
  2023年   2篇
  2022年   2篇
  2019年   4篇
  2018年   6篇
  2017年   8篇
  2016年   4篇
  2015年   5篇
  2014年   3篇
  2013年   3篇
  2011年   2篇
  2010年   2篇
  2009年   3篇
  2008年   2篇
  2007年   4篇
  2006年   5篇
  2005年   2篇
  2004年   3篇
  2003年   3篇
  2002年   2篇
  2001年   3篇
  1999年   2篇
  1998年   10篇
  1997年   3篇
  1996年   3篇
  1995年   2篇
  1993年   2篇
  1991年   5篇
  1990年   3篇
  1989年   2篇
  1986年   2篇
  1985年   2篇
  1984年   1篇
  1983年   1篇
  1980年   1篇
  1976年   1篇
  1973年   1篇
  1971年   1篇
  1970年   1篇
  1967年   1篇
  1966年   2篇
  1962年   1篇
  1958年   1篇
  1956年   1篇
  1955年   1篇
  1952年   1篇
  1951年   1篇
  1949年   1篇
  1947年   2篇
  1935年   1篇
  1925年   1篇
排序方式: 共有131条查询结果,搜索用时 15 毫秒
41.

Background  

A high prevalence of CAM use has been documented worldwide in children and adolescents with chronic illnesses. Only a small number of studies, however, have been conducted in the United Kingdom. The primary aim of this study was to examine the use of CAM by children and adolescents with a wide spectrum of acute and chronic medical problems in a tertiary children's hospital in Wales.  相似文献   
42.
Expert assessment of walking behavior in pain patients represents an important element of the exploratory examination in manual medicine. As part of the Sommerfelder Diagnostic System, a plan useful for clinical application was devised for differential evaluation of functional disorders of the musculoskeletal system and their possible effects on movement behavior based on gait appraisal. Following standardized muscle function and stereotype tests, specific criteria were established for regional evaluation of body regions and global assessment of movement behavior during walking. This contribution illustrates how technical approaches, e.g., video-assisted movement analysis, can ensure a high quality of expert assessment of walking behavior. Gait analysis on the treadmill offers decisive advantages over analysis of horizontal walking for specific questions. Video-assisted gait analysis only permits semiquantitative determination of kinematic parameters unless further objectifying systems are employed simultaneously. Gait analysis facilitates clearer verification of disorders in the movement chains taking into consideration key regions for manual medicine.  相似文献   
43.
Miltefosine (hexadecylphosphocholine, HPC, CAS 58066-85-6) was investigated in transplanted primary methylnitrosourea-induced PYH mammary carcinoma of F344 rats. The therapy was performed in the 5th and 10th passage. At first HPC (113 mg/kg body weight) significantly reduced the median tumor volume, but a loss of activity was observed in the 10th passage. To explain the loss of sensitivity and to obtain information on the mechanism of action histology, cytoskeleton and hormone receptor content were investigated. The most important change was observed in the histopathology of the tumor. The initial tubular papillary adenocarcinoma was transformed into a malignant adenoacanthoma with epithelial structure. Vimentin as an endothelial marker of the cytoskeleton was equally expressed in all passages. Cytokeratin was weakly expressed in the earlier passages and intensively present in the late passages. The histopathological change from tubular adenocarcinoma to malignant adenoacanthoma might be caused by an overgrowth of the primary epithelial tumor cells or by a real transformation in the morphological characteristics of the tumor, which may occur during repeated transplantation.  相似文献   
44.
Twenty rats were randomized into a vesicosigmoidostomy and an unoperated control group. In both groups the 24 hour excretion of secondary amines, nitrate, nitrite and nitrosamines was measured before and after gavage of proline and nitrate, piperazine and nitrate, N-nitrosoproline, mono-N-nitrosopiperazine. The urinary nitrosamine concentrations were not significantly different between both groups neither before nor after application of the several substances. Thirty rats were randomized into two vesicosigmoidostomy groups with and without antibiotic coverage and an unoperated control group. After ligation of distal rectum and mesosigmoid the rectosigmoids were removed. No significant concentrations of volatile nitrosamines could be measured in the rectosigmoid contents of the three groups. One hundred and twenty rats randomized into three groups following vesicosigmoidostomy received the potential nitrosamine antidotes sodium-2-mercaptoethane sulfonate or sodiumpentosan-polysulfate or acted as controls. 12/118 (10.2%) developed adenomas and 25/118 (21.2%) adenocarcinomas at the vesico-colonic anastomosis with no significant differences between the three groups concerning tumor incidence or mortality. The results show that colon carcinomas occur in a rat model for ureterosigmoidostomy without evidence for thus induced nitrosamine formation. This and the missing effect of nitrosamine antidotes suggest that other factors than nitrosation must be responsible for colon carcinogenesis following urinary diversion via intestine.  相似文献   
45.
Acetylenic analogues of tuftsin (Thr-Dah-Pro-Arg) and of a macrophage inhibitory tripeptide (Thr-Dah-Pro) have been synthesized by conventional procedures in solution (Dah = 2,6-diamino-4-hexynoic acid). These acetylenic derivatives are intermediates for the preparation of structurally unmodified, tritiated peptides. Catalytic tritiation of Thr-Dah-Pro-Arg and of Thr-Dah-Pro has afforded the radioactive tetra- and tripeptides with specific activities of 11.4 Ci/mmol and 37 Ci/mmol, respectively.  相似文献   
46.
The red cell-monocyte assay (RMA), which has been used to evaluate the clinical significance of red cell (RBC) antibodies, was employed to test the effect of the dialyzable leukocyte extract (DLE) on in vitro adherence to monocytes of human RBCs coated with alloantibodies or autoantibodies. The total association index (TAI) of the RMA, expressing the number of RBCs adhering to or phagocytosed by 100 monocytes, indicated a potent inhibitory activity of DLE in the test system. TAI values of 100.4 +/- 20.1 (mean +/- SD) in the control sample, consisting of RBCs coated in vitro with anti-D, dropped to 4.0 +/- 2.1 when DLE was present in the assay medium at a concentration of 0.5 U per mL. Similar results were obtained with RBCs coated with IgG antibodies in vivo. The inhibition was dose dependent and was associated with a thermolabile component of DLE. This study establishes that DLE can modulate monocyte function by inhibiting the recognition of IgG sensitized red cells.  相似文献   
47.
Pedophilia is a heterogeneous disorder for which the neurobiological correlates are not well established. In particular, there are no biological markers identifying individuals with high risk to commit child sexual offense (CSO). Pedophiles with CSO (P+CSO; N = 73), pedophiles without CSO (P-CSO; N = 77), and non-pedophilic controls (NPC; N = 133) were assessed using multimodal structural neuroimaging measures including: cortical thickness (CT), surface area (SA), and white matter fractional anisotropy (FA), as well as full scale IQ (FSIQ) performance. Cortex-wise mediation analyses were used to assess the relationships among brain structure, FSIQ and CSO behavior. Lower FSIQ performance was strongly predict with P+CSO (Wald Chi2 = 13.0, p = 3.1 × 10-5). P+CSO had lower CT in the right motor cortex and pronounced reductions in SA spanning the bilateral frontal, temporal, cingulate, and insular regions (PFWE-corrected < 0.05). P+CSO also had lower FA particularly in the corpus callosum (PFWE-corrected < 0.05). The relationship between SA and P+CSO was significantly mediated by FSIQ, particularly in the prefrontal and anterior insular cortices (PFWE-corrected < 0.05). Within P+CSO, left prefrontal and right anterior cingulate SA negatively correlated with number of CSOs (PFWE-corrected < 0.05). This study demonstrates converging neurobiological findings in which P+CSO had lower FSIQ performance, reduced CT, reduced SA, and reduced FA, compared to P-CSO as well as NPC. Further, FSIQ potentially mediates abuse by pedophiles via aberrant SA, whereas the CT and FA associations were independent of FSIQ differences. These findings suggest aberrant neuroanatomy and lower intelligence as a potential core feature underlying child sexual abuse behavior by pedophiles.  相似文献   
48.

Background

In oncology clinical trials, crossover is used frequently but may lead to uncertainties regarding treatment effects.

Objective

To investigate the handling of evidence from crossover trials by the European Medicines Agency (EMA) and the German Federal Joint Committee (G-BA).

Methods

For oncology medicines with early benefit assessments before January 2015, presence of crossover, clinical data, EMA requests for additional data, and G-BA benefit ratings/evidence levels were analyzed from manufacturers’ dossiers, G-BA appraisals, European Public Assessment Reports, and original publications.

Results

Eleven of 21 benefit assessments included crossover trials. Significant intergroup differences (P < 0.05) in overall survival (OS) were noted in 7 of 11 trials with and 7 of 10 without crossover. For 6 of 11 medicines with crossover, these were demonstrated before crossover. Treatment effects generally worsened with increasing proportions of crossover. The EMA requested additional data more frequently if crossover was performed, particularly if no OS data were available before crossover. The G-BA granted a considerable benefit to 73% of medicines with crossover and 40% of those without. Evidence levels were intermediate for 50% and 75%, respectively. None of the medicines received the highest evidence level.

Conclusions

In G-BA appraisals, oncology medicines with crossover received better additional benefit ratings, but were assigned lower evidence levels, than those without. The five medicines with crossover after progression were assigned lower evidence levels than the six medicines with crossover after demonstration of superior OS, indicating that the way in which crossover is implemented may be one factor influencing the assignment of evidence levels by the G-BA.  相似文献   
49.
Physical and economic consequences of climate change in Europe   总被引:3,自引:0,他引:3  
Quantitative estimates of the economic damages of climate change usually are based on aggregate relationships linking average temperature change to loss in gross domestic product (GDP). However, there is a clear need for further detail in the regional and sectoral dimensions of impact assessments to design and prioritize adaptation strategies. New developments in regional climate modeling and physical-impact modeling in Europe allow a better exploration of those dimensions. This article quantifies the potential consequences of climate change in Europe in four market impact categories (agriculture, river floods, coastal areas, and tourism) and one nonmarket impact (human health). The methodology integrates a set of coherent, high-resolution climate change projections and physical models into an economic modeling framework. We find that if the climate of the 2080s were to occur today, the annual loss in household welfare in the European Union (EU) resulting from the four market impacts would range between 0.2-1%. If the welfare loss is assumed to be constant over time, climate change may halve the EU's annual welfare growth. Scenarios with warmer temperatures and a higher rise in sea level result in more severe economic damage. However, the results show that there are large variations across European regions. Southern Europe, the British Isles, and Central Europe North appear most sensitive to climate change. Northern Europe, on the other hand, is the only region with net economic benefits, driven mainly by the positive effects on agriculture. Coastal systems, agriculture, and river flooding are the most important of the four market impacts assessed.  相似文献   
50.
The reaction of isolated helical strips of rat aorta to X-irradiation was studied: X-rays (50 kV) induced a reproducible, reversible contractile response at threshold doses of 2.5 Gy (60 Gy/min) and 10 Gy (30 Gy/min). After repeated irradiation with the same doses at equal time intervals and constant dose-rate (for example 50 Gy every 15 min, dose-rate 60 Gy/min) the contractile response was progressively diminished, i.e. a tachyphylaxis appeared. The preparations still reacted even after total doses over 1000 Gy. The X-ray induced contractile responses were dose- and dose-rate dependent. Quantitative analysis indicated no essential differences in the radiation-induced contractile response when recorded under isometric or isotonic conditions. After hypothermia (20 degrees C) or hyperthermia (42 degrees C) no visible radiation response could be induced. Part of the aortic strips were spontaneously active: X-ray doses of 5 to 10 Gy stimulated, while doses of 100 to 200 Gy inhibited or blocked the spontaneous phasic activity. A comparison between the immediate X-ray reaction of vascular and non-vascular smooth muscle preparations is given. Participation of cholinergic and adrenergic mechanisms in the X-ray induced contractions of rat aorta seems to be ruled out, because the blocking agents atropine, phentolamine, and bretylium had no effect.  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