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41.
To assess the dosimetric effect of using interpolated contours in planning intensity‐modulated radiation therapy (IMRT) for advanced T‐stage nasopharyngeal carcinoma. The present study focused on T3–T4 tumours where the proximity of targets to neurological organs poses a stringent test on the feasibility of such an approach. Contours of targets and organs were delineated on CT images of 2.5‐mm interval and a reference IMRT plan was generated. An investigative (INV) IMRT plan was then generated with the same planning protocol, but based on interpolated contours that replaced deleted contours on alternate slices. The reference and INV plans were compared. Regarding target coverage, all targets in the INV plans met the acceptance criteria except for the PTV in one case. Regarding organs, the mean dose to 1% volume of the brainstem and spinal cord in the INV plans were kept below their dose limits. No significant differences in the mean doses to others organs were found. Satisfactory target coverage and protection of critical organs to a degree similar to full‐scale contouring could be achieved with use of interpolated contours. The saving in manpower time for contouring is expected to significantly improve the throughput of the IMRT planning process.  相似文献   
42.
A Monte Carlo simulation model is presented which allows an assessment of the costs for coronary heart disease (CHD) (from a social security perspective) to be made over a time interval of 10 years. The difference between a CHD population and a normal population is calculated whereby the CHD population corresponds in terms of age and gender distribution to a German population with existing hypercholesteremia. The data were generated from the results of the German Cardiovascular Prevention Trial (DHP), a population was determined which represents the age group of the 45- to 65-year-old German population. Both direct as well as indirect costs were taken into account. The model simulates 2 submodels: 1. CHD is already present in the observed population. 2. A proportion of the observed cases of hypercholesteremia develop CHD over a time interval of 10 years, whereby normal distribution of the events is assumed. From the social security perspective, the cumulative costs of CHD for the observed age group who already have CHD amount to approximately 59 billion DM in 10 years (see Table 4). On the assumption that CHD develops during the course of these 10 years and that the population does not already present with CHD at the start of the simulation model, the costs are calculated to be about 41 billion DM (see Table 3). Numerous sensitivity analyses were carried out which showed that the assumption of the direct costs per case/year were highly sensitive (see Figure 1). The special advantage of the model is the perspective chosen, since social security is considered as a whole and interactions between individual branches of social security become transparent.  相似文献   
43.
44.
This report reviews the state of the literature and opportunities for research related to "executive control function" (ECF). ECF has recently been separated from the specific cognitive domains (memory, language, and praxis) traditionally used to assess patients. ECF impairment has been associated with lesions to the frontal cortex and its basal ganglia-thalamic connections. No single putative ECF measure can yet serve as a "gold standard." This and other obstacles to assessment of ECF are reviewed. ECF impairment and related frontal system lesions and metabolic disturbances have been detected in many psychiatric and medical disorders and are strongly associated with functional outcomes, disability, and specific problem behaviors. The prevalence and severity of ECF deficits in many disorders remain to be determined, and treatment has been attempted in only a few disorders. Much more research in these areas is necessary.  相似文献   
45.
During the last 20 years, there has been growing literature on the consequences of population aging. Longer life expectancies mean that current cohorts can expect to spend more years as members of a family than was the case 200 years ago. The focus of this paper is on how three lineage generations are affected by the increase of the life expectancy, especially the increase in a multi-generational family and the common life time of the family members. Using event history analysis and the data of the German Socio-economic panel, it is shown, on the basis of different birth cohorts, that both Word Wars and the period after World War II have had profound negative effects on the common life time of grandfathers and their grandchildren. But there has been only a limited influence on the life courses of grandmothers and their grandchildren. One surprising result is that grandparenthood in Germany has developed into a broader phenomenon of the 20th century -- one that arose especially for children born after World War II.  相似文献   
46.
Radiation‐induced mucositis is an acute reaction of the mucosa of patients undergoing head and neck radiotherapy. It can have debilitating and dose‐limiting consequences. There is no consensus on an accepted intervention that significantly reduces its severity. Misoprostol is a synthetic prostaglandin E1 analogue, with properties of a mucosal cytoprotectant. We designed a randomized, double‐blind, placebo‐controlled trial of misoprostol in patients with head and neck cancer. The aim of this study was to determine if topical misoprostol was effective in reducing the severity of radiation‐induced mucositis in patients receiving radical dose radiotherapy. The effect of this intervention on a patient’s general well‐being was also investigated. The primary end‐point of the study was the incidence of Radiation Therapy Oncology Group grade 3 mucositis. Between 1999 and 2002, 83 patients were recruited into the study at Westmead and Nepean Hospitals, Sydney. Forty‐two patients were randomized to receive misoprostol and 41 to receive a placebo. Most patients received radiotherapy in the adjuvant setting (52 of the 83) and had either an oral cavity (42 of the 83) or an oropharyngeal (16 of the 83) cancer. We could not identify any significant difference in the incidence of severe mucositis based on whether patients were allocated to receive misoprostol or placebo. There was no significant difference in the mean area under the mucositis curve (13.2 vs 16.6; P = 0.1). Patients allocated to misoprostol did report slightly increased soreness (7.6 vs 6.9; P = 0.04) and a greater use of analgesics. However, this difference did not translate into a worse feeling of general well‐being as measured by a simple visual analogue scale (5.8 vs 5.2; P = 0.3). In conclusion, we were unable to identify a reduction in radiation‐induced mucositis in patients receiving misoprostol. There is a paucity of high‐level evidence on potentially useful interventions and a continued need for new and innovative research, incorporating quality‐of‐life measurements, in patients experiencing radiation‐induced mucositis.  相似文献   
47.
48.
HYPOTHESIS: Infragenicular polytetrafluoroethylene (PTFE)-venous cuff bypass grafting provides acceptable graft patency and limb salvage rates for limb salvage. DESIGN: Retrospective clinical review of a consecutive series. SETTING: Vascular surgical practice during the interval October 1, 2000, to September 1, 2004. PATIENTS: Fifty-one male and 49 female patients whose mean age was 76.9 years were operated on for tissue loss (67%), chronic rest pain (28%), and severe claudication (6%). Fifty-two percent of patients were diabetic and 49% had undergone previous leg bypass surgery. All patients had absent or inadequate greater saphenous vein, and 84 patients had absent or inadequate arm vein. INTERVENTIONS: One hundred five infragenicular PTFE bypasses were performed in these 100 patients. Distal targets were the infragenicular popliteal (40), posterior tibial (35), anterior tibial (16), and peroneal arteries (14). Sixty-eight venous cuffs were constructed from lesser saphenous vein. MAIN OUTCOME MEASURES: Graft patency, limb salvage, and patient survival were analyzed. RESULTS: Twelve early graft failures resulted in 7 leg amputations. The mean +/- SE 3-year primary patency and limb salvage rates were 64.4% +/- 12.8% and 74.4% +/- 11.9%, respectively. Perioperative mortality was 2.9% and 3-year survival was 38%. Graft follow-up ranged from 1 to 47 months with a mean of 13 months using life-table methods. CONCLUSIONS: For patients requiring arterial revascularization for limb salvage, in which autologous venous conduit is unavailable, distal venous cuff-PTFE bypass provides acceptable patency and limb salvage rates when viewed in the context of short life expectancy for these elderly patients.  相似文献   
49.
The subproject 1.5 "Neurobiology of Suicidal Behavior" is a multicenter study assessing peripheral parameters of the serotonergic, noradrenergic, and dopaminergic transmitter systems. Additionally, stress hormones and the lipid system as well as inhibitory and excitatory amino acids will be investigated. The different parameters are collected in cerebral spinal fluid (CSF), blood, and saliva. Patients with a depressive spectrum disorder with and without a suicide attempt (during the last three weeks) and being medication free for two weeks are included in the study. So far, 103 patients and controls have been recruited. The design and development of this project as well as interconnections with the others subprojects are described. Preliminary results about the stress hormone system and suicidality are presented.  相似文献   
50.
Pentoxyfylline in and prevention and treatment of chronic lung disease   总被引:1,自引:0,他引:1  
The anti-inflammatory effects of pentoxfylline are associated with a number of clinical benefits. These include reduction in mortality in patients who have undergone bone marrow transplants or suffer peritonitis. In infants with sepsis, a reduction in mortality has also been associated with pentoxyfylline administration. The anti-inflammatory effects of pentoxyfylline, as well as its bronchodilator, diuretic and respiratory muscle stimulant effects suggest it may have a useful role in BPD. Interim analysis of a prophylactic trial suggests pentoxyfylline may reduce treatment requirements after the neonatal period and that, in established BPD, pentoxyfylline and dexamethasone may be of similar efficacy.  相似文献   
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