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   208篇
  免费   6篇
  国内免费   2篇
耳鼻咽喉   5篇
儿科学   3篇
妇产科学   6篇
基础医学   28篇
临床医学   25篇
内科学   37篇
神经病学   30篇
特种医学   7篇
外科学   14篇
预防医学   28篇
眼科学   3篇
药学   21篇
肿瘤学   9篇
  2018年   2篇
  2013年   2篇
  2012年   18篇
  2011年   25篇
  2010年   1篇
  2009年   4篇
  2008年   20篇
  2007年   18篇
  2006年   22篇
  2005年   23篇
  2004年   19篇
  2003年   16篇
  2002年   19篇
  2001年   1篇
  2000年   5篇
  1999年   3篇
  1998年   1篇
  1997年   1篇
  1991年   2篇
  1990年   3篇
  1988年   3篇
  1987年   1篇
  1985年   1篇
  1977年   1篇
  1975年   1篇
  1972年   1篇
  1969年   1篇
  1966年   2篇
排序方式: 共有216条查询结果,搜索用时 15 毫秒
91.
92.
Behavioral consequences of long-term methadone treatment have received little attention either in humans or experimental animals. In this work, we show that methadone (2.5-10 mg/kg) administered (sc) once daily for three weeks with repeated withdrawal on Saturday and Sunday impairs the novelty preference in rats. One hour after the last injection, when methadone was still present in brain tissue, the rats were too affected by the sedative effects of the drug to perform the test. This was confirmed by an almost total lack of locomotor activity or exploratory behavior. One day after the last injection, the methadone treated rats showed a 70% reduction (p < 0.05) in novelty preference compared to rats administered saline. No methadone was detected in the brain tissue at this time. Moreover, there were no differences in locomotor activity or total exploratory behavior between the groups, indicating a specific impairment of cognitive functioning. In brain tissue, the methadone concentration versus time profile was shifted to the left after long-term treatment, indicating a change in uptake and distribution of the drug. The area under the two concentration versus time curves was, however, similar. Methadone disappeared completely from the brain within one day. Together, these results suggest that long-term methadone treatment may have a negative impact on cognitive functioning in rats, regardless of whether methadone is present in brain tissue.  相似文献   
93.
An ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS-MS) method for screening of drugs in whole blood has been developed and validated. Samples were prepared by supported liquid-liquid extraction on ChemElute(?) columns with ethyl acetate/heptane (4:1). LC separation was achieved with an Acquity HSS T3-column (2.1 100 mm, 1.8-μm particle). Mass detection was performed by positive ion mode electrospray MS-MS and included the following drugs/metabolites: morphine, codeine, ethyl morphine, oxycodone, buprenorphine, methadone, cocaine, methylphenidate, amphetamine, methamphetamine, 3,4-methylenedioxymethamphetamine (MDMA), Δ(9)-tetrahydrocannabinol (THC), fentanyl, alprazolam, bromazepam, clonazepam, diazepam, nordiazepam, 3-OH-diazepam, fenazepam, flunitrazepam, lorazepam, nitrazepam, oxazepam, zopiclone, zolpidem, carisoprodol, and meprobamate. The cycle time was 9 min, and within- and between-day relative coefficients of variation varied from 1% to 33% and 2% to 58%, respectively. Extraction recoveries from whole blood were > 50% except for morphine and THC. The limit of quantitation was 0.1 to 521 ng/mL, depending on the drug.  相似文献   
94.
The importance of patient-reported outcomes such as health-related quality of life (HRQL) in clinical research is increasingly acknowledged. In order to yield valid results, the measurement properties of HRQL questionnaires must be thoroughly investigated. One aspect of such a validation process is the demonstration of content validity, i.e. that the questionnaire covers all relevant aspects. We review studies reporting on consequences of thyroid disorders and present the frequency of identified aspects, both overall HRQL issues and classical thyroid symptoms, in order to evaluate which issues are relevant for patients with thyroid diseases. Furthermore, existing questionnaires for thyroid patients are reviewed. A systematic search was performed in the Medline, Cinahl and Psycinfo databases and the reference lists of the relevant articles were hand-searched. Seventy-five relevant studies were identified. According to these studies, patients with untreated thyroid disease suffer from a wide range of symptoms and have major impairment in most areas of HRQL. Furthermore, the studies indicate that impairments in HRQL are also frequent in the long term. Six HRQL questionnaires for thyroid patients were identified. Generally, data supporting the validity of these questionnaires were sparse. According to the available literature, the quality of life of thyroid patients is substantially impaired over a wide range of aspects of HRQL in the untreated phase and continues to be so in many patients also in the long term. Studies systematically exploring the relative importance of these various aspects to thyroid patients are lacking, as is a comprehensive, validated thyroid-specific HRQL questionnaire.  相似文献   
95.
96.
Cytochrome P4501A (CYP1A) induction was evaluated in the rat hepatoma cell line H4IIE as a biomarker of exposure to organic compounds. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazoliumbromide assay was performed to assess the viability of cells exposed to environmentally relevant concentrations of cadmium. Cadmium concentrations greater than approximately 0.7 microM were found to affect cell viability. Cells were exposed to environmentally relevant concentrations of 3,3',4,4'-tetrachlorobiphenyl (PCB 77) or benzo[a]pyrene (BaP) and to combinations of PCB 77, BaP, and cadmium based on a statistical experimental design. Quantification of CYP1A proteins using Western blot analysis showed that both BaP and PCB 77 induced CYP1A in a concentration-dependent manner up to 5 microM. Response surface modeling for evaluation of the combined effect of compounds was conducted using the multivariate regression model projection to latent structures (PLS). Analysis of response surface models for the ternary mixtures indicated antagonistic interactions between BaP and PCB 77 and a possible inhibitory effect of cadmium on PCB 77- induced CYP1A. Use of CYP1A induction in the H4IIE cell line with immunodetection of CYP1A proteins, combined with the application of response surface design and PLS, is shown to be a suitable strategy for evaluating combined effects in pollutant mixtures.  相似文献   
97.
OBJECTIVE: It was the aim of this study to determine the prevalence and severity of fatigue among optimally treated HIV patients and to investigate the potential association with systemic inflammation and abnormalities of the distribution of cerebral glucose metabolism. METHODS: A cohort of HIV patients (n = 95), known to be HIV positive for 5 years, on anti-retroviral therapy for a minimum of 3 years and with CD4 counts above 0.2 x 10(9) cells/l, completed a validated fatigue inventory, and plasma was analysed for pro-inflammatory markers including tumour necrosis factor-alpha, interleukin 6 and soluble urokinase receptor (suPAR) levels. The distribution of the regional cerebral metabolic rate of glucose was measured in a sub-group of patients suffering from severe fatigue (n = 9) and a group with no fatigue (n = 7) using fluorine-18-fluorodeoxyglucose positron emission tomography (FDG-PET) scanning. RESULTS: Fifteen percent suffered from severe fatigue, but no association with pro-inflammatory markers was found. About 50% of the FDG-PET-scanned patients showed minor abnormalities in the relative cerebral metabolic rate of glucose. These abnormalities were not associated with fatigue but tended to correlate with a short HIV history (p = 0.058), a low CD4 nadir (p = 0.082) and elevated tumour necrosis factor-alpha levels (p = 0.074). CONCLUSION: Fatigue is common among optimally treated HIV patients. FDG-PET-described signs of imminent neurodegeneration among HIV patients who had a low CD4 nadir may illustrate an aspect of HIV neuropathogenicity.  相似文献   
98.
We described a 5-month-old girl with Aicardi syndrome accompanied by auditory disturbance and multiple brain tumors. She was admitted to our hospital because she suffered from intractable flexor spasms. Physical examination revealed craniofacial asymmetry, left auricular deformity, scoliosis, and remarkable hypotonia with psychomotor retardation. Abnormal ophthalmological findings included chorioretinopathy with pale and round-shaped peripapillary lacunae, and there was modified hypsarrhythmia in her EEG. MRI revealed multiple brain tumors in the 3rd and the lateral ventricles which are considered to be choroid plexus papilloma with agenesis of the corpus callosum. ACTH therapy was administered because of the intractable seizures. After ACTH therapy, the thresholds of waves I and V were much improved. The interpeak latency of waves I-V of the left ear and the peak latency of wave I of the right ear had been lengthened. Acoustic reflex with contralateral stimulation showed no response in the left ear. These findings indicate that the auditory system is also involved in the Aicardi syndrome and that ACTH is effective for its dysfunction.  相似文献   
99.
A comprehensive, SPECT-based, patient-specific 3-dimensional (3D) dosimetry analysis has been performed using 3D-ID, a previously developed software package. The role of the total-body tumor burden, individual lesion size, tumor absorbed dose, and the spatial distribution of the absorbed dose on response and on the time course of tumor shrinkage has been examined in patients with lymphoma treated by radioimmunotherapy. METHODS: Data from 15 patients participating in a phase II study of (131)I-labeled anti-B1 antibody (tositumomab) were used. Patients were administered a tracer dose of (131)I for imaging and pharmacokinetics. Dose estimates from the tracer studies were used to prescribe the therapeutic administration such that the whole-body absorbed dose did not exceed 75 cGy. All patients received a fixed mass amount of antibody for both the tracer and the therapeutic administrations. SPECT and planar imaging were performed 3-4 d after the therapeutic administration. CT or MRI scans were available on all patients. Total tumor burden was assessed by drawing contours around all lymphoma lesions identified on whole-body CT or MRI. Mean absorbed doses were estimated for selected, index lesions by conventional dosimetry and also by 3D SPECT-based dosimetry. Using a patient-specific dosimetry package, 3D-ID, dose-volume histograms were also generated to assess the spatial distribution of absorbed dose. This approach made it possible to obtain estimates of the minimum and maximum absorbed doses for individual tumors in addition to the mean. RESULTS: Mean absorbed dose estimates obtained by patient-specific SPECT-based dosimetry using 3D-ID were within 2%-5% of estimates obtained by conventional dosimetry. None of the absorbed dose parameters (mean, minimum, maximum, uniformity) were found to have a significant correlation with tumor response. The total-body tumor burden did not impact on overall response or toxicity. CONCLUSION: This analysis represents the first full reported implementation of a patient-specific 3D dosimetry package. The absence of a dose-response relationship for tumors is surprising and suggests that absorbed dose is not the sole determinant of tumor response in these patients. The absence of a correlation between the total-body tumor burden and overall response or toxicity suggests that tailoring the milligram amount of administered antibody to patient tumor burden is not likely to improve response or reduce toxicity.  相似文献   
100.
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