全文获取类型
收费全文 | 175642篇 |
免费 | 837篇 |
国内免费 | 18篇 |
专业分类
耳鼻咽喉 | 1131篇 |
儿科学 | 6659篇 |
妇产科学 | 3015篇 |
基础医学 | 16569篇 |
口腔科学 | 1541篇 |
临床医学 | 12354篇 |
内科学 | 30901篇 |
皮肤病学 | 666篇 |
神经病学 | 16460篇 |
特种医学 | 8893篇 |
外科学 | 28749篇 |
综合类 | 2376篇 |
预防医学 | 18065篇 |
眼科学 | 2727篇 |
药学 | 9419篇 |
中国医学 | 632篇 |
肿瘤学 | 16340篇 |
出版年
2022年 | 22篇 |
2021年 | 49篇 |
2020年 | 28篇 |
2019年 | 48篇 |
2018年 | 21953篇 |
2017年 | 17386篇 |
2016年 | 19528篇 |
2015年 | 910篇 |
2014年 | 822篇 |
2013年 | 764篇 |
2012年 | 6955篇 |
2011年 | 20992篇 |
2010年 | 18801篇 |
2009年 | 11498篇 |
2008年 | 19466篇 |
2007年 | 21669篇 |
2006年 | 503篇 |
2005年 | 2136篇 |
2004年 | 3336篇 |
2003年 | 4304篇 |
2002年 | 2450篇 |
2001年 | 281篇 |
2000年 | 416篇 |
1999年 | 173篇 |
1998年 | 205篇 |
1997年 | 203篇 |
1996年 | 94篇 |
1995年 | 105篇 |
1994年 | 107篇 |
1993年 | 61篇 |
1992年 | 54篇 |
1991年 | 93篇 |
1990年 | 136篇 |
1989年 | 94篇 |
1988年 | 78篇 |
1987年 | 58篇 |
1986年 | 47篇 |
1985年 | 50篇 |
1984年 | 35篇 |
1983年 | 34篇 |
1982年 | 32篇 |
1980年 | 46篇 |
1969年 | 20篇 |
1939年 | 20篇 |
1938年 | 60篇 |
1937年 | 25篇 |
1935年 | 22篇 |
1934年 | 30篇 |
1932年 | 56篇 |
1930年 | 46篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
41.
Usha Rani Gogoi Mrinal Kanti Bhowmik Debotosh Bhattacharjee Anjan Kumar Ghosh 《Australasian physical & engineering sciences in medicine / supported by the Australasian College of Physical Scientists in Medicine and the Australasian Association of Physical Sciences in Medicine》2018,41(4):861-879
The purpose of this study is to develop a novel breast abnormality detection system by utilizing the potential of infrared breast thermography (IBT) in early breast abnormality detection. Since the temperature distributions are different in normal and abnormal thermograms and hot thermal patches are visible in abnormal thermograms, the abnormal thermograms possess more complex information than the normal thermograms. Here, the proposed method exploits the presence of hot thermal patches and vascular changes by using the power law transformation for pre-processing and singular value decomposition to characterize the thermal patches. The extracted singular values are found to be statistically significant (p?<?0.001) in breast abnormality detection. The discriminability of the singular values is evaluated by using seven different classifiers incorporating tenfold cross-validations, where the thermograms of the Department of Biotechnology-Tripura University-Jadavpur University (DBT-TU-JU) and Database of Mastology Research (DMR) databases are used. In DMR database, the highest classification accuracy of 98.00% with the area under the ROC curve (AUC) of 0.9862 is achieved with the support vector machine using polynomial kernel. The same for the DBT-TU-JU database is 92.50% with AUC of 0.9680 using the same classifier. The comparison of the proposed method with the other reported methods concludes that the proposed method outperforms the other existing methods as well as other traditional feature sets used in IBT based breast abnormality detection. Moreover, by using Rank1 and Rank2 singular values, a breast abnormality grading (BAG) index has also been developed for grading the thermograms based on their degree of abnormality. 相似文献
42.
Chhavi Raj Bhatt Mary Redmayne Michael J. Abramson Malcolm R. Sim Christopher Brzozek Berihun M. Zeleke Geza Benke 《Australasian physical & engineering sciences in medicine / supported by the Australasian College of Physical Scientists in Medicine and the Australasian Association of Physical Sciences in Medicine》2018,41(4):985-991
The aims of this study were to evaluate the weekly and annual cumulative radiofrequency-electromagnetic field (RF-EMF) exposure attributed to mobile phone (MP) use, and assess whether a novel app (Quanta Monitor?) could be employed in a small human sample to characterise the RF-EMF exposures associated with the use of MPs. Ten participants provided their two months’ daily objective data on their MP exposures (i.e. transmitted and received power densities) attributed to different modes of MP usage such as cellular calls, cellular data and Wi-Fi. The results demonstrated that total transmitted power density (cellular phone calls, data and Wi-Fi surfing) could be many orders of magnitude higher than that from the total received power density. Of the total transmitted power density, cellular data use contributed the largest portion. Our study showed that Quanta Monitor? could be employed in prospective assessment of exposures to MPs in epidemiological studies. 相似文献
43.
Xiuxia Li Lili Wei Wenru Shang Xin Xing Min Yin Juan Ling Kuoray Mao Yiliang Zhu Kehu Yang 《Zeitschrift fur Gesundheitswissenschaften》2018,26(2):127-135
Aim
To provide a systematic review of the existing theory, framework, systems and instruments for tracing and evaluating quality in rural health services.Subjects and methods
We searched six electronic databases up to March 2016. Observational studies of quality assessment of rural health services using theoretical models were included. Ekman’s scale was used to evaluate the quality of the included studies.Results
A total of 18 studies, published between 2001 and 2015, met the inclusion criteria. The corresponding authors for most of them (7, 44%) are from Chinese institutions and three (3, 17%) from Australian institutions. Five studies (28%) focused on township hospitals. Primary health care quality was reported in five studies (28%), followed by clinical service in four (22%). More than half of the studies (61%) were considered of high quality, and the remainder was of moderate quality. These studies applied 16 theoretical systems, including the model/pattern (4, 25%), method/tool (7, 44%) and framework of the theory (5, 31%). Most of the theoretical models (14, 88%) obtained positive observations. In addition, the conceptual model (6, 36%) and TOPSIS method (2, 13%) were more frequently reported.Conclusion
Although most of the current studies were considered to have high-quality and positive results, there were limitations in the number of publications and research on theoretical systems. The lacks of unified standards and comprehensive evaluation are important issues that need to be pointed out and resolved.44.
45.
Purpose
The number of single households has increased worldwide with middle-aged people in such households indicating the highest increase. However, there is a lack of studies on the topic. This study estimated the quality of life (QOL) by household type for middle-aged Korean adults.Methods
We used the Korea National Health and Nutrition Examination Survey data from 2007 to 2015. QOL was analyzed using EQ-5D 3-level, and demographic and health-related variables were included as confounders. The households were divided into single household, married couple without child, other one-generation, married couple with child, single parent with child, other two-generation, and three-generation. Logistic regression using level, strata, and sample weight of data was performed based on average QOL.Results
This study included 18,147 responders aged 45–64 years, with single households constituting 5.7%. Single households having average or less QOL were 48.4%, with men and women constituting 40.1 and 53.3%, respectively. After adjusting socioeconomic factors and health-related factors, the odds ratio (OR) of single households was 1.375 (95% CI 1.122–1.684) compared to the three-generation group. According to the sex, the OR of single households with men was higher (OR 1.552, 95% CI 1.121–2.149). However, no significance was found in women.Conclusions
The study results revealed that middle-aged people in single households had low QOL than those in multi-person households. The trend was significantly observable in men than in women. Because middle-aged adults might transform into elderly with low QOL, program development and social support for middle-aged adults in single households should be provided.46.
Gabriel Gijon-Nogueron Laura Ramos-Petersen Ana Belen Ortega-Avila Jose Miguel Morales-Asencio Silvia Garcia-Mayor 《Quality of life research》2018,27(12):3059-3069
Background
Epidemiological studies consistently report a 90% prevalence of foot pain. Mechanical and other non-pharmacological interventions such as orthoses and footwear can play an important role in managing foot pathology in patients whose systemic disease is controlled. The effectiveness of treatment with insoles has been examined in various randomised controlled trials, which have reported immediate clinical improvements, with reduced foot pain and disability and enhanced functionality. The aim of this systematic review is to determine the effectiveness of foot orthoses in patients with rheumatoid arthritis (RA), in comparison with other treatments, in terms of enhanced disability and reduced pain.Methods
A systematic review and meta-analysis was conducted of a number of randomised controlled trials focusing on patients with RA. The search was conducted in Cochrane, CINAHL, PubMed, EMBASE, SCOPUS and Cuiden, by means of an independent peer review. The Mesh terms and fields used were foot, ankle, joint, RA, foot, orthosis, insole and foot orthosis.Results
Of the initial 118 studies considered, 5 were included in the final systematic review and meta-analysis. These five studies had enrolled a total of 301 participants, with follow-up periods ranging from 4 to 36 months. Although the use of orthoses seems to alleviate foot pain, our meta-analysis did not reveal statistically significant differences between control and intervention groups regarding long- and short-term pain relief and/or reduced disability.Conclusions
Foot orthoses can relieve pain and disability and enhance patients, but no significant differences were found between control and intervention groups.47.
Jana Le Diana S. Dorstyn Elias Mpofu Elise Prior Phillip J. Tully 《Quality of life research》2018,27(10):2505-2505
48.
Aaron Yarlas Martha Bayliss Joseph C. Cappelleri Stephen Maher Andrew G. Bushmakin Lea Ann Chen Alireza Manuchehri Paul Healey 《Quality of life research》2018,27(2):273-290
Purpose
To conduct a systematic literature review of the reliability, construct validity, and responsiveness of the SF-36® Health Survey (SF-36) in patients with ulcerative colitis (UC).Methods
We performed a systematic search of electronic medical databases to identify published peer-reviewed studies which reported scores from the eight scales and/or two summary measures of the SF-36 collected from adult patients with UC. Study findings relevant to reliability, construct validity, and responsiveness were reviewed.Results
Data were extracted and summarized from 43 articles meeting inclusion criteria. Convergent validity was supported by findings that 83% (197/236) of correlations between SF-36 scales and measures of disease symptoms, disease activity, and functioning exceeded the prespecified threshold (r ≥ |0.40|). Known-groups validity was supported by findings of clinically meaningful differences in SF-36 scores between subgroups of patients when classified by disease activity (i.e., active versus inactive), symptom status, and comorbidity status. Responsiveness was supported by findings of clinically meaningful changes in SF-36 scores following treatment in non-comparative trials, and by meaningfully larger improvements in SF-36 scores in treatment arms relative to controls in randomized controlled trials. The sole study of SF-36 reliability found evidence supporting internal consistency (Cronbach’s α ≥ 0.70) for all SF-36 scales and test–retest reliability (intraclass correlation coefficient ≥0.70) for six of eight scales.Conclusions
Evidence from this systematic literature review indicates that the SF-36 is reliable, valid, and responsive when used with UC patients, supporting the inclusion of the SF-36 as an endpoint in clinical trials for this patient population.49.
Purpose
Most computerized adaptive testing (CAT) applications in patient-reported outcomes (PRO) measurement to date are reliability-centric, with a primary objective of maximizing measurement efficiency. A key concern and a potential threat to validity is that, when left unconstrained, individual CAT administrations could have items with systematically different attributes, e.g., sub-domain coverage. This paper aims to provide a solution to the problem from an optimal test design framework using the shadow-test approach to CAT.Methods
Following the approach, a case study was conducted using the PROMIS® (Patient-Reported Outcomes Measurement Information System) fatigue item bank both with empirical and simulated response data. Comparisons between CAT administrations without and with the enforcement of content and item pool usage constraints were examined.Results
The unconstrained CAT exhibited a high degree of variation in items selected from different substrata of the item bank. Contrastingly, the shadow-test approach delivered CAT administrations conforming to all specifications with a minimal loss in measurement efficiency.Conclusions
The optimal test design and shadow-test approach to CAT provide a flexible framework for solving complex test-assembly problems with better control of their domain coverage than for the conventional use of CAT in PRO measurement. Applications in a wide array of PRO domains are expected to lead to more controlled and balanced use of CAT in the field.50.