全文获取类型
收费全文 | 1811篇 |
免费 | 126篇 |
国内免费 | 41篇 |
专业分类
耳鼻咽喉 | 9篇 |
儿科学 | 13篇 |
妇产科学 | 10篇 |
基础医学 | 255篇 |
口腔科学 | 71篇 |
临床医学 | 305篇 |
内科学 | 161篇 |
皮肤病学 | 13篇 |
神经病学 | 66篇 |
特种医学 | 77篇 |
外科学 | 223篇 |
综合类 | 250篇 |
一般理论 | 1篇 |
预防医学 | 183篇 |
眼科学 | 3篇 |
药学 | 105篇 |
1篇 | |
中国医学 | 147篇 |
肿瘤学 | 85篇 |
出版年
2024年 | 14篇 |
2023年 | 56篇 |
2022年 | 108篇 |
2021年 | 136篇 |
2020年 | 96篇 |
2019年 | 69篇 |
2018年 | 65篇 |
2017年 | 58篇 |
2016年 | 80篇 |
2015年 | 74篇 |
2014年 | 143篇 |
2013年 | 129篇 |
2012年 | 106篇 |
2011年 | 114篇 |
2010年 | 88篇 |
2009年 | 93篇 |
2008年 | 91篇 |
2007年 | 66篇 |
2006年 | 57篇 |
2005年 | 59篇 |
2004年 | 34篇 |
2003年 | 46篇 |
2002年 | 38篇 |
2001年 | 15篇 |
2000年 | 20篇 |
1999年 | 16篇 |
1998年 | 6篇 |
1997年 | 10篇 |
1996年 | 6篇 |
1995年 | 12篇 |
1994年 | 10篇 |
1993年 | 9篇 |
1992年 | 6篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 5篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有1978条查询结果,搜索用时 0 毫秒
31.
Binghu Jiang Dongmei He Liwen Zhang Min Ye 《Journal of neuroradiology. Journal de neuroradiologie》2019,46(2):117-123
Background and purpose
It is not conclusive that magnetic resonance (MR)-based carotid atherosclerotic plaque assessment identifies high-risk features associated with cerebrovascular events. We aimed to systematically summarize the association of MR imaging (MRI)-determined intraplaque hemorrhage (IPH), lipid-rich necrotic core (LRNC), and thinning/rupture of the fibrous cap (TRFC) with subsequent ischemic events.Materials and methods
We performed a comprehensive literature search evaluating the association of MRI-based carotid plaque composition with ischemic outcomes. We included cohort studies examining IPH, LRNC, or TRFC with mean follow-up of ≥ 6 months and an outcome measure of ipsilateral ischemic events. A meta-analysis was done according to the Cochrane guideline.Results
We identified 13 studies including 1.150 patients and 1.208 analyzed carotid arteries, with mean follow-up of 21.1 months. The hazard ratios (HR) for IPH, LRNC, and TRFC as predictors of subsequent ischemic events were 4.41 (95% CI: 2.87, 6.79), 3.00 (95% CI: 1.51, 5.95), and 5.94 (95% CI: 2.66, 13.28), respectively. The predictive value of carotid plaque MRI for ischemic events was acceptable, with sensitivity of 0.80 (95% CI: 0.66, 0.90) and specificity of 0.63 (95% CI: 0.57, 0.68). However, it was limited to confirm or exclude future ischemic events in clinical context, with positive likelihood ratio (LR) of 2.2 (95% CI: 1.9, 2.5) and negative LR of 0.31 (95% CI: 0.18, 0.55). No statistically significant heterogeneity or publication bias was observed.Conclusion
The presence of IPH, LRNC, and TRFC determined by MRI is associated with increased risk of future ischemic events, but its predictive value is moderate and should not be used for confirmation or exclusion of future ischemic events in clinical context. 相似文献32.
A number of initiatives are underway in the United States in response to the 2009 critique of forensic science by a National Academy of Sciences committee. This article provides a broad review of activities including efforts of the White House National Science and Technology Council Subcommittee on Forensic Science and a partnership between the Department of Justice (DOJ) and the National Institute of Standards and Technology (NIST) to create the National Commission on Forensic Science and the Organization of Scientific Area Committees. These initiatives are seeking to improve policies and practices of forensic science. Efforts to fund research activities and aid technology transition and training in forensic science are also covered.The second portion of the article reviews standards in place or in development around the world for forensic DNA. Documentary standards are used to help define written procedures to perform testing. Physical standards serve as reference materials for calibration and traceability purposes when testing is performed. Both documentary and physical standards enable reliable data comparison, and standard data formats and common markers or testing regions are crucial for effective data sharing. Core DNA markers provide a common framework and currency for constructing DNA databases with compatible data. Recent developments in expanding core DNA markers in Europe and the United States are discussed. 相似文献
33.
Koichi Otani Akihito Suzuki Toshinori Shirata Keisuke Noto Muneaki Kanno 《International journal of psychiatry in clinical practice》2020,24(3):278-283
AbstractObjective: Core beliefs about negative-self are beliefs about self-deficiencies in basic aspects of human adaptation. Meanwhile, neuroticism is a personality trait characterised by negative emotionality, i.e., a tendency to react to stress with negative emotions. The present study tested the hypothesis that core beliefs about negative-self are implicated in neuroticism.Methods: The subjects were 309 Japanese healthy volunteers. Core beliefs about negative-self were evaluated by the Brief Core Schema Scales, and neuroticism was evaluated by the NEO Personality Inventory-Revised.Results: In both multiple regression analysis and structural equation modelling, higher neuroticism was strongly predicted by higher levels of core beliefs about negative-self.Limitations: The present study cannot determine the causal relationship between core beliefs about negative-self and neuroticism, because of its cross sectional design.Conclusions: The present study suggests that core beliefs about negative-self are deeply implicated in neuroticism.
- Key Points
Implication of core beliefs about negative-self in neuroticism was examined.
Neuroticism was predicted by higher levels of these core beliefs.
These core beliefs may be involved in negative emotionality of neuroticism.
34.
YU Yi YAN Kai?ping WANG Yan SUN Shu?qing CHEN Jin LIN Kai?ping YI Jian?wei. 《中华肾脏病杂志》2012,28(11):868-872
Objective To study the relationship between the medial artery calcification and expression of core?binding factor alpha 1 (Cbfα?1) and collagen Ⅱ (ColⅡ) in chronic kidney disease(CKD) stage 5 patients. Methods Pieces of radial arteries were taken from 40 patients with CKD stage 5 during internal arteriovenous fistula operation. Ten patients with subtotal gastrectomy and normal renal function were chosen as control. The vessels were examined for calcification by von Kossa stain and for the presence of Cbfα?1 and ColⅡ by immunohistochemistry. According to von Kossa stain, CKD stage 5 patients were divided into no calcification group, mild?moderate calcification group and severe calcification group. Other related factors including serum calcium,phosphate, intact parathyroid hormone (iPTH), C?reactive protein (CRP), triglyceride(TG), cholesterol(TC) and low?density lipoproteins(LDL) were also detected. Results Seventeen (42.5%) of CKD Stage 5 patients showed vascular calcification, while calcification was not found in controls. Most calcification occurred in medial layer.Positive immunohistochemical staining of core?binding factor and ColⅡ was found in the smooth muscular cell plasma of medial layer in the vessels with calcification. However, above positive staining was also observed in 78.3% of no calcification group. But there was little staining in control group. Positive staining score of Cbfα?1 and ColⅡ in severe calcification group was significantly higher than that in no calcification group. Same findings were obtained in mild?moderate calcification group, but the difference between them was not statistically significant. CRP and Ca×P were positively correlated with staining score of Cbfα?1 and ColⅡ. Serum phosphate was positively correlated with Cbfα?1 (r=0.786, P<0.01) and ColⅡ (r=0.785, P<0.01) respectively. Conclusions 42.5% of CKD stage 5 patients in our group shows vascular calcification, which occurrs mainly in medial layer. High expression of Cbfα?1 and ColⅡ can be observed in vascular calcification of radial arteries, which is earlier than vascular histological changes. Cbfα?1 and ColⅡ may be involved in the development of vascular calcification. 相似文献
35.
目的探讨乙型肝炎病毒(Hepatitis B Virus,HBV)前C基因区变异与HBV-DNA载量的关系。方法通过DNA扩增、基因序列分析检测21例慢性肝炎、18例肝硬化和15例肝癌血清的HBV前C区和基本核心启动子(Basic Core Promoter,BCP)基因序列,荧光定量聚合酶链反应技术定量检测血清中的HBV-DNA。结果野生株与前C区终止变异、BCP双变异以及联合变异组HBV-DNA载量测定差异无显著性(P〉0.05);BCP双变异HBV-DNA载量HBeAg(-)组显著高于HBeAg(+)组(P〉0.05)。结论前C区终止变异和BCP双变异对HBV DNA复制无明显影响。HBeAg(-)的慢性肝病患者BCP变异后HBV DNA复制明显活跃。 相似文献
36.
The objective of the study was to identify commonalities among the International Classification of Functioning, Disability
and Health (ICF) Core Sets of osteoarthritis (OA), osteoporosis (OP), low back pain (LBP), rheumatoid arthritis (RA) and chronic
widespread pain (CWP). The aim is to identify relevant categories for the development of a tentative ICF Core Set for musculoskeletal
and pain conditions. The ICF categories common to the five musculoskeletal and pain conditions in the Brief and Comprehensive
ICF Core Sets were identified in three steps. In a first step, the commonalities across the Brief and Comprehensive ICF Core
Sets for these conditions were examined. In a second and third step, we analysed the increase in commonalities when iteratively
excluding one or two of the five conditions. In the first step, 29 common categories out of the total number of 120 categories
were identified across the Comprehensive ICF Core Sets of all musculoskeletal and pain conditions, primarily in the component
activities and participation. In the second and third step, we found that the exclusion of CWP across the Comprehensive ICF
Core Sets increased the commonalities of the remaining four musculoskeletal conditions in a maximum of ten additional categories.
The Brief ICF Core Sets of all musculoskeletal and pain conditions contain four common categories out of a total number of
62 categories. The iterative exclusion of a singular condition did not significantly increase the commonalities in the remaining.
Based on our analysis, it seems possible to develop a tentative Comprehensive ICF Core Set across a number of musculoskeletal
conditions including LBP, OA, OP and RA. However, the profile of functioning in people with CWP differs considerably and should
not be further considered for a common ICF Core Set. 相似文献
37.
38.
Gayle Langley William Schaffner Monica M. Farley Ruth Lynfield Nancy M. Bennett Arthur Reingold Ann Thomas Lee H. Harrison Megin Nichols Susan Petit Lisa Miller Matthew R. Moore Stephanie J. Schrag Fernanda C. Lessa Tami H. Skoff Jessica R. MacNeil Elizabeth C. Briere Emily J. Weston Chris Van Beneden 《Emerging infectious diseases》2015,21(9):1520-1528
Active Bacterial Core surveillance (ABCs) was established in 1995 as part of the Centers for Disease Control and Prevention Emerging Infections Program (EIP) network to assess the extent of invasive bacterial infections of public health importance. ABCs is distinctive among surveillance systems because of its large, population-based, geographically diverse catchment area; active laboratory-based identification of cases to ensure complete case capture; detailed collection of epidemiologic information paired with laboratory isolates; infrastructure that allows for more in-depth investigations; and sustained commitment of public health, academic, and clinical partners to maintain the system. ABCs has directly affected public health policies and practices through the development and evaluation of vaccines and other prevention strategies, the monitoring of antimicrobial drug resistance, and the response to public health emergencies and other emerging infections. 相似文献
39.
40.
《Chest》2020,157(6):1647-1655