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51.
There are many factors influencing the accuracy of surface topography measurement results: one of them is the vibrations caused by the high-frequency noise occurrence. It is extremely difficult to extract results defined as noise from the real measured data, especially the application of various methods requiring skilled users and, additionally, the improper use of software may cause errors in the data processing. Accordingly, various thresholding methods for the minimization of errors in the raw surface topography data processing were proposed and compared with commonly used (available in the commercial software) techniques. Applied procedures were used for the minimization of errors in the surface topography parameters (from ISO 25178 standard) calculation after the removal and reduction, respectively, of the high-frequency noise (S-filter). Methods were applied for analysis of the laser-textured surfaces with a comparison of many regular methods, proposed previously in the commercial measuring equipment. It was found that the application of commonly used algorithms can be suitable for the processing of the measured data when selected procedures are provided. Moreover, errors in both the measurement process and the data processing can be reduced when thresholding methods support regular algorithms and procedures. From applied, commonly used methods (regular Gaussian regression filter, robust Gaussian regression filter, spline filter and fast Fourier transform filter), the most encouraging results were obtained for high-frequency noise reduction in laser-textured details when the fast Fourier transform filter was supported by a thresholding approach.  相似文献   
52.
BackgroundAnticardiolipin antibodies (aCL) and anti‐β2‐glycoprotein I antibodies (aβ2GPI) are essential in diagnosing antiphospholipid syndrome (APS) according to the international APS guideline. Five commercial assays for aCL and aβ2GPI are available in Japan, but their test results are quite discordant. For harmonization of diagnosing APS, upper reference limit (URL) and diagnostic accuracy of each assay were evaluated and compared by testing common sets of specimens across all assays.MethodsWe evaluated two manual and three automated assays for aCL and aβ2GPI of IgG‐ and IgM classes. 99%URL (the upper limit of reference interval: as per guideline) together with 97.5%URL were determined by testing sera from 198 to 400 well‐defined healthy subjects. Both URLs were compared with the cutoff values, which were determined based on ROC analysis by testing 50 each of plasma specimens from patients with/without APS. Diagnostic accuracy was evaluated as area under curve (AUC) of the ROC curve.ResultsA variable degree of discrepancy between URLs and the cutoff values was observed, which was partly attributable to between‐year assay variability. 97.5%URLs were set lower and closer to the cutoff values than 99%URLs. For all assays, diagnostic accuracies of both aβ2GPI‐IgG and aCL‐IgG were generally high (AUC: 0.84−0.93); whereas those for IgM‐class assays were low (AUC: 0.57−0.67), implicating its utility is limited to rare IgG negative APS cases.ConclusionTo ensure harmonized APS diagnosis, the diagnostic thresholds of the five assays were evaluated by common procedures. Contrary to the guideline, 97.5%URL is rather recommended for diagnosing APS, which showed a closer match to the cutoff value.  相似文献   
53.
目的:探讨人巨细胞病毒(HCMV)核酸定量检测试剂(PCR-荧光探针法)的临床使用及初步评价。方法:用浓缩一步法试剂与煮沸法试剂对192例临床收集的样本进行HCMV DNA检测并对比其结果,同时,将两种试剂的检测结果分别与HCMV-pp65抗原检测结果进行对比。结果:新型人巨细胞病毒核酸检测试剂与煮沸法试剂的阳性一致性百分比98.06%,阴性一致性百分比95.51%,总一致性百分比96.88%;对6例不符样本进行测序复核,并对复核后的结果进行Kappa检验一致性分析,结果 Kappa值=1.000,表明新型试剂的检测结果与煮沸法试剂及复核检测的结果具有很好的一致性。在与HCMV-pp5抗原检测结果的对比中,两种试剂均表现出较好的准确性。结论:人巨细胞病毒核酸检测试剂与煮沸法试剂检测结果具有很好一致性,操作简单快速,减少污染环节,并具有内标控制假阴性,结果准确,符合临床检测要求,具有较高的应用价值。  相似文献   
54.
IntroductionIndividuals with cystic fibrosis (CF) may be at increased risk of pulmonary embolism (PE). Symptoms of PE overlap substantially with those of CF respiratory exacerbations. CF patients commonly undergo chest computed tomography (CT) angiograms (CTPA) to evaluate for PE, but little is known about the clinical presentation and diagnosis of PE in this population.ObjectivesThe objectives of this study are to determine the diagnostic yield of CTPA for PE in adult patients with CF and assess the utility of the Revised Geneva Score (RGS) in this population.MethodsRetrospective review of all CTPA results was performed on CF patients with suspected PE at a large CF center from 1 January 2011 through 31 March 2017. Patient demographics, medical history, and presenting signs and symptoms were abstracted by chart review.ResultsA total of 103 unique CTPA studies were performed in 68 patients. Most were hospitalized at the time of CTPA, predominantly for respiratory manifestations of CF. CTPA identified four patients with PE. The small number of positive studies precluded analysis of predictors of PE. Fewer PE were diagnosed than predicted by the Revised Geneva Score, which was intermediate probability in 77/103 (75%) patients.ConclusionThe prevalence of PE in CF patients undergoing CTPA for suspected PE was 4%, which is lower than predicted by the Revised Geneva Score. This may be due to a large overlap in the signs and symptoms of PE and exacerbations of CF lung disease.  相似文献   
55.
ObjectiveThis study investigated the role of objective olfactory dysfunction (OD) and gustatory dysfunction (GD) testing among patients with suspected coronavirus disease 2019 (COVID-19) who presented with respiratory symptoms.MethodsA prospective, blinded, observational study was conducted in the emergency units of two tertiary hospitals. Participants were asked to identify scents in the pocket smell test (PST) and flavors in four different solutions in the gustatory dysfunction test (GDT). We assessed the level of agreement between objective findings and self-reported symptoms. We evaluated the diagnostic accuracy of chemosensory dysfunction for diagnosing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.ResultsOf 250 participants, 74 (29.6%) were SARS-CoV-2-positive. There was slight agreement between self-reported symptoms and objective findings (kappa = 0.13 and 0.10 for OD and GD, respectively). OD assessed by the PST was independently associated with COVID-19 (adjusted odds ratio = 1.89, 95% confidence interval, 1.04–3.46). This association was stronger when OD was combined with objective GD, cough, and fever (adjusted odds ratio = 7.33, 95% confidence interval, 1.17–45.84).ConclusionsNeither the PST nor GDT alone are useful screening tools for COVID-19. However, a diagnostic scale based on objective OD, GD, fever, and cough may help triage patients with suspected COVID-19.  相似文献   
56.
57.
One of the most basic biostatistical problems is the comparison of two binary diagnostic tests. Commonly, one test will have greater sensitivity, and the other greater specificity. In this case, the choice of the optimal test generally requires a qualitative judgment as to whether gains in sensitivity are offset by losses in specificity. Here, we propose a simple decision analytic solution in which sensitivity and specificity are weighted by an intuitive parameter, the threshold probability of disease at which a patient will opt for treatment. This gives a net benefit that can be used to determine which of two diagnostic tests will give better clinical results at a given threshold probability and whether either is superior to the strategy of assuming that all or no patients have disease. We derive a simple formula for the relative diagnostic value, which is the difference in sensitivities of two tests divided by the difference in the specificities. We show that multiplying relative diagnostic value by the odds at the prevalence gives the odds of the threshold probability below which the more sensitive test is preferable and above which the more specific test should be chosen. The methodology is easily extended to incorporate combinations of tests and the risk or side effects of a test. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
58.
K. Khan 《Statistics in medicine》2013,32(14):2443-2456
Diagnostic tests are traditionally compared for accuracy against a gold standard but can also be compared prospectively in a trial. A conventional trial comparing two tests would randomize each participant to a testing strategy, but a more efficient alternative is to give both tests to all participants and follow up those with discordant results. Participants could be randomized before or after testing. The statistical analysis of such a trial has not previously been described. We investigated two estimates of the risk difference for a binary outcome: one based on analysing outcomes as if from a conventional trial and one combining estimates of different parameters in the manner of a decision analysis. We show that the trial estimate and decision analysis estimate are both unbiased and derive approximate formulae for their standard errors. By using the decision analysis estimate (but not the trial estimate), the same precision can be achieved by randomizing before testing as by randomizing after. To avoid destroying equipoise, and to allow consenting and randomizing to be carried out at the same visit, we recommend randomizing before testing. Giving both tests to all participants means fewer need to be recruited: in one example from the literature, the proposed design was nearly four times more efficient in this sense than a conventional trial design. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
59.
《Women & health》2013,53(3):63-81
ABSTRACT

Women increasingly outnumber men in the US population (Arber & Ginn, 1993), but most research has been conducted with men (Stacey & Olesen, 1988). The purpose of this study was to determine whether older men and women differ in their participation rates and in their responsiveness to a health intervention. Three hundred sixty-three health maintenance organization members with osteoarthritis, 60 years of age or older, were randomly assigned to a control group or to receive social support, education, or a combination of education and social support. Of the 363 randomly assigned members, 245 completed all of the follow-up assessments. Men and women volunteered in proportion to their representation in the osteoarthritis population. Although the genders differed in several ways, the interventions were equally effective for men and women, and the study results applied to both genders.  相似文献   
60.
Effect of azelastine nasal spray on histamine-and allergen-induced skin test response in patients suffering with allergic rhinitis was evaluated. Baseline cutaneous response to histamine and 18 common allergen extracts were recorded by skin prick tests on 10 patients. The patients were then advised to take azelastine nasal spray (1 spray per nostril, twice daily; 0.28 mg/dose). This pediatric dose is reported to be effective also in adults (age ≥ 12 years) with improved tolerability as compared with usually recommended adult dose of 2 sprays per nostril twice daily. Skin tests were repeated 2 and 6 hours after single dose, as well as after 6 days of continuous treatment. We did not find any significant difference in skin wheal response with single dose and 6 days' treatment of azelastine nasal spray (p > 0.05). It is concluded that diagnostic allergen skin tests may be performed on patients undergoing azelastine nasal spray treatment (0.28 mg/dose, twice a day) during their symptomatic period.  相似文献   
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