全文获取类型
收费全文 | 177502篇 |
免费 | 994篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 1137篇 |
儿科学 | 6640篇 |
妇产科学 | 3015篇 |
基础医学 | 16768篇 |
口腔科学 | 1562篇 |
临床医学 | 12517篇 |
内科学 | 31275篇 |
皮肤病学 | 742篇 |
神经病学 | 16597篇 |
特种医学 | 9005篇 |
外科学 | 29273篇 |
综合类 | 2329篇 |
预防医学 | 18198篇 |
眼科学 | 2759篇 |
药学 | 9592篇 |
中国医学 | 626篇 |
肿瘤学 | 16469篇 |
出版年
2022年 | 25篇 |
2021年 | 68篇 |
2020年 | 26篇 |
2019年 | 50篇 |
2018年 | 21953篇 |
2017年 | 17374篇 |
2016年 | 19523篇 |
2015年 | 928篇 |
2014年 | 849篇 |
2013年 | 832篇 |
2012年 | 7093篇 |
2011年 | 21153篇 |
2010年 | 18889篇 |
2009年 | 11584篇 |
2008年 | 19662篇 |
2007年 | 21838篇 |
2006年 | 704篇 |
2005年 | 2340篇 |
2004年 | 3533篇 |
2003年 | 4497篇 |
2002年 | 2612篇 |
2001年 | 277篇 |
2000年 | 414篇 |
1999年 | 182篇 |
1998年 | 245篇 |
1997年 | 241篇 |
1996年 | 109篇 |
1995年 | 124篇 |
1994年 | 120篇 |
1993年 | 87篇 |
1992年 | 55篇 |
1991年 | 93篇 |
1990年 | 133篇 |
1989年 | 82篇 |
1988年 | 63篇 |
1987年 | 46篇 |
1986年 | 32篇 |
1985年 | 35篇 |
1984年 | 30篇 |
1983年 | 31篇 |
1982年 | 32篇 |
1980年 | 53篇 |
1974年 | 24篇 |
1969年 | 22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 15 毫秒
991.
Tingxu Yan Lei Shang Mengshi Wang Chenning Zhang Xu Zhao Kaishun Bi Ying Jia 《Metabolic brain disease》2016,31(3):653-661
The aim of this study was to explore the neuroprotective effects of active compounds from Schisandra chinensis (Trucz.) Baill. (Magnoliaceae) against the D-galactose (D-gal)-induced neurotoxicity in rat. The Wistar rats were subcutaneously injected with D-gal (150 mg/(kg day)) for six weeks and orally administered with water extract or 95 % ethanol extract (partitioned with petroleum ether (PE), chloroform (CF), ethyl acetate (EA) and n-Butanol (NB), respectively) of the fruits of Schisandra chinensis simultaneously. The alteration of cognitive functions was assessed by using Morris water maze and Step-down type passive avoidance test. The results demonstrated that PE fraction was the most effective fraction to ameliorate cognitive deficits. Further biochemical examination indicated that PE could attenuate the activities decreasing of superoxide dismutase (SOD), catalase (CAT), the total antioxidant (T-AOC) induced by D-gal, and maintain the normal levels of glutathione (GSH), malondialdehyde (MDA) and nitric oxide (NO) in the serum, prefrontal cortex, striatum and hippocampus of the brain of related rat, selectively. Meanwhile, the compounds of PE fraction were also identified as mainly lignans, thus, these results suggest that lignans from the PE fraction of Schisandra chinensis represented a potential source of medicine for the treatment of the aging-associated neurodegenerative diseases. 相似文献
992.
Steven A. Wartman Patricia S. O’Sullivan Michele G. Cyr 《Journal of general internal medicine》1990,5(1):S59-S69
Residency programs consist of a range of activities involving service to patients and education of residents. The observation that a conflict exists between the service and education components of residency is widespread and has been used to explain many of the problems afflicting such programs today. The authors believe that the service/education conflict is a significant barrier to change in residency programs. A model is presented for residency education that reorganizes the service and education components. First, they present a broad overview of the conflict. Then they provide a brief historical perspective and comment on some of the current recommendations for residency programs. Next, they discuss how principles of adult learning relate to residency and propose a new model of residency that adheres more closely to these principles. Finally, the proposed model is presented in some detail and its implications are discussed. Only if the service and education components of residency are carefully delineated can residency programs adapt to the changing and growing needs of postgraduate medical education. 相似文献
993.
The SWAL–QOL and SWAL–CARE Outcomes Tool for Oropharyngeal Dysphagia in Adults: III. Documentation of Reliability and Validity 总被引:3,自引:0,他引:3
McHorney CA Robbins J Lomax K Rosenbek JC Chignell K Kramer AE Bricker DE 《Dysphagia》2002,17(2):97-114
Advances in the measurement of swallowing physiologic parameters have been clinician-driven, as has the development of intervention
techniques to modify swallowing pathophysiology. However, a critical element to determining the success of such efforts will
be established by the patients themselves. We conceptualized, developed, and validated the SWAL–QOL, a 93-item quality-of-life
and quality-of-care outcomes tool for dysphagia researchers and clinicians. With 93 items, the SWAL–QOL was too long for practical
and routine use in clinical research and practice. We used an array of psychometric techniques to reduce the 93-item instrument
into two patient-centered outcomes tools: (1) the SWAL–QOL, a 44-item tool that assesses ten quality-of-life concepts, and
(2) the SWAL–CARE, a 15-item tool that assesses quality of care and patient satisfaction. All scales exhibit excellent internal-consistency
reliability and short-term reproducibility. The scales differentiate normal swallowers from patients with oropharyngeal dysphagia
and are sensitive to differences in the severity of dysphagia as clinically defined. It is intended that the standardization
and publication of the SWAL–QOL and the SWAL–CARE will facilitate their use in clinical research and clinical practice to
better understand treatment effectiveness as a critical step toward improving patients' quality of life and quality of care. 相似文献
994.
Community-acquired pneumonia (CAP) is common, costly, and clinically serious. Several national and international practice guidelines have been developed to promote more appropriate, cost-effective care for patients with CAP. This article compares and contrasts eight international practice guidelines for the management of CAP, describes the extent to which recommendations are reflected in practice, and proposes explanations for non-adherence to guidelines. We found consistency in recommendations across all the guidelines for the management of patients with CAP requiring intensive care. In this setting, all guidelines recommend chest radiography, sputum Gram stain and culture, blood cultures, testing for Legionella pneumophila, and timely administration of antibiotics active against both typical (i.e. Streptococcus pneumoniae, Hemophilus influenzae) and atypical organisms (i.e. Legionella spp., Mycoplasma pneumoniae, and Chlamydia pneumoniae). Recommendations for the management of the average inpatient with pneumonia were more variable, with the greatest differences between the North American and European guidelines. The North American guidelines (in contrast to European ones), recommended empiric treatment of typical and atypical organisms in all inpatients. There were also differences in policies regarding the necessity of chest radiography, sputum studies, and serologic testing. Some guidelines explicitly embrace the use of prediction rules to inform the decision to hospitalize, while others do not. Some of these admission decision algorithms focus on identifying low risk patients, while others are most concerned with high risk patients. There was also considerable variation in the specificity and operationalization of clinical criteria for switching from parenteral to oral antibiotics or judging appropriateness for discharge. Many recommendations for key management decisions tended to lack explicit, objective, and actionable criteria that could be easily implemented in real world practice. Review of the pneumonia literature revealed that physician performance of guideline-recommended best practices is often suboptimal. Administration of timely antibiotics (< or =8 hours of presentation) and use of first-line antibiotics occurred in 75-85% and 18-79% of cases, respectively. Collection of blood cultures within 24 hours of presentation and prior to administration of antibiotics was achieved in 69-83% and 63-82% of cases, respectively. Screening the eligibility of CAP patients for hospital-based pneumococcal and influenza vaccination occurred on average in 11 and 14% of hospitalizations, respectively, in the US. Lack of awareness of guidelines, conflicting advice among them, and lack of specific, objective, actionable recommendations most likely contribute to nonadherence to CAP guidelines. Increased attention to these factors will be needed if professional society practice guidelines are to fulfill their promise as tools for improving the quality and outcomes of care for patients with pneumonia. 相似文献
995.
Lifeng Lin Haitao Chu Mohammad Hassan Murad Chuan Hong Zhiyong Qu Stephen R. Cole Yong Chen 《Journal of general internal medicine》2018,33(8):1260-1267
Background
Decision makers rely on meta-analytic estimates to trade off benefits and harms. Publication bias impairs the validity and generalizability of such estimates. The performance of various statistical tests for publication bias has been largely compared using simulation studies and has not been systematically evaluated in empirical data.Methods
This study compares seven commonly used publication bias tests (i.e., Begg’s rank test, trim-and-fill, Egger’s, Tang’s, Macaskill’s, Deeks’, and Peters’ regression tests) based on 28,655 meta-analyses available in the Cochrane Library.Results
Egger’s regression test detected publication bias more frequently than other tests (15.7% in meta-analyses of binary outcomes and 13.5% in meta-analyses of non-binary outcomes). The proportion of statistically significant publication bias tests was greater for larger meta-analyses, especially for Begg’s rank test and the trim-and-fill method. The agreement among Tang’s, Macaskill’s, Deeks’, and Peters’ regression tests for binary outcomes was moderately strong (most κ’s were around 0.6). Tang’s and Deeks’ tests had fairly similar performance (κ?>?0.9). The agreement among Begg’s rank test, the trim-and-fill method, and Egger’s regression test was weak or moderate (κ <?0.5).Conclusions
Given the relatively low agreement between many publication bias tests, meta-analysts should not rely on a single test and may apply multiple tests with various assumptions. Non-statistical approaches to evaluating publication bias (e.g., searching clinical trials registries, records of drug approving agencies, and scientific conference proceedings) remain essential.996.
997.
Impact of reflux esophagitis on the esophageal function before and after laparoscopic fundoplication
Masato Hoshino Nobuo Omura Fumiaki Yano Kazuto Tsuboi Se Ryung Yamamoto Shunsuke Akimoto Takahiro Masuda Hideyuki Kashiwagi Katsuhiko Yanaga 《Esophagus》2018,15(4):224-230
Background
High-resolution manometry (HRM), which is breakthrough testing equipment to evaluate esophageal motor function, was developed in Europe and United State and has garnered attention. Moreover, multichannel intraluminal impedance pH (MII-pH) testing has allowed us to grasp all liquid/gas reflux including not only acid but also non-acid reflux. We examined the impact of the presence of reflux esophagitis (RE) on esophageal motor function before and after laparoscopic fundoplication.Materials and methods
The subjects included 100 patients (male: 63 patients, mean age: 54.1?±?15.8) among 145 patients who underwent laparoscopic fundoplication for GERD associated diseases during a 4-year period from October 2012 to September 2016, excluding 6 patients who underwent further surgery, 32 patients on whom HRM was not performed, 3 patients who had technical errors during testing, and 4 patients for whom the status of RE was unknown. Regarding HRM, Mano Scan from Given Imaging Ltd. was used, and for the analysis, Mano View version 3.0 from the same company was used, after which data was calculated based on the Chicago Classification advocated by Pandolfino et al. Moreover, for the MII-pH testing, Sleuth manufactured by Sandhill Scientific. Inc. was used and automatic analysis was conducted by a computer. Postoperative assessments were conducted 3 months following surgery for all. Data was described in the median value and inter-quartile range, with a statistically significant difference defined as p?<?0.05 by Chi square, Mann–Whitney, and Wilcoxon tests.Results
RE+?group (Los Angeles classification A:B:C:D?=?7:9:16:12 patients) included 44 patients (44%), of older age compared to the RE? group (62 vs. 50 years, p?=?0.012) and a higher Body Mass Index value (24.0 vs. 22.5, p?=?0.045); however, no differences were observed in terms of gender and duration of symptoms. In the preoperative findings on MII-pH, the RE+?group demonstrated significantly longer acid reflux time (4.7 vs. 1.3%, p?=?0.005), while in the HRM findings, the RE? group demonstrated a significantly longer abdominal esophagus (0 vs. 0.4 cm, p?=?0.049) and maintained esophageal body motor function (DCI: 1054 vs. 1407 mmHg s cm, p?=?0.021, Intact peristalsis ratio: 90 vs. 100%, p?=?0.037). As to the comparison of the treatment effect before and after laparoscopic fundoplication (Toupet fundoplication for all), significant improvements were observed in both groups in various parameters regarding reflux including acid reflux time, total number of liquid reflux episodes and total number of reflux episodes. Moreover, for both groups, the total length of the lower esophageal sphincter (LES) (RE+?group: 2.7 vs. 3.2 cm, p?=?0.001, RE? group: 3.0 vs. 3.4 cm, p?=?0.003) and the total length of the abdominal esophagus (RE+?group: 0 vs. 1.6 cm, p?<?0.001, RE? group: 0 vs. 1.8 cm, p?=?0.001) were significantly extended following surgery; however, no change was observed in DCI before and after surgery.Conclusions
Regardless of the presence of RE, cardiac function and LES function were improved following laparoscopic Toupet fundoplication, but no changes were observed in esophageal body motor function.998.
999.
Heart failure in women 总被引:1,自引:0,他引:1
Barnard DD 《Current cardiology reports》2005,7(3):159-165
Increasingly high mortality from cardiovascular disease in women has sparked nationwide campaigns to raise awareness of this
significant threat to women’s health. Heart failure has the most lethal prognosis of the major cardiovascular diseases, yet
women demonstrate an apparent survival advantage compared with men. Sex-linked disparities in heart failure risk factors and
pathophysiology contribute to this divergent clinical outcome. Heart failure etiology and clinical manifestations unique to
female sex exist. At age 40, the lifetime risk of developing heart failure is equal for men and women, whereas the lifetime
risk of developing coronary heart disease is one in two for men and one in three for women. Understanding sex-inherent characteristics
related to heart failure may help determine whether the optimal therapy for this prevalent syndrome should be modified according
to sex. Until prospective trial data prove otherwise, heart failure treatment guidelines should be uniformly applied to both
women and men. 相似文献
1000.
The obesity gene product leptin plays an important role in the physiologic regulation of appetite and energy balance. Plasma
leptin levels correlate closely with body fat storage and may respond to changes in energy expenditure. Recent evidence has
implicated a direct cardiac regulatory action of leptin in addition to its well-established metabolic properties. Compelling
evidence has indicated a link between abnormal leptin levels (hyper-or hypoleptinemia) and cardiac dysfunction. The leptin-deficient
ob/ob mice have been used as a model for insulin resistance, obesity, and type 2 diabetes. Leptin replenishment has been shown
to restore the depressed cardiac contractile function in ob/ob mice, indicating a permissive role of leptin in cardiac function. The precise role of leptin or leptin deficiency on cardiac
health has not been fully elucidated. This article briefly reviews leptin’s physiologic role in cardiomyocyte structure and
function and how leptin deficiency or disrupted signaling may trigger cardiac functional and morphologic abnormalities. 相似文献