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   27096篇
  免费   2951篇
  国内免费   604篇
耳鼻咽喉   150篇
儿科学   992篇
妇产科学   523篇
基础医学   2051篇
口腔科学   322篇
临床医学   3003篇
内科学   6441篇
皮肤病学   401篇
神经病学   1524篇
特种医学   515篇
外科学   2691篇
综合类   2381篇
现状与发展   1篇
一般理论   12篇
预防医学   5802篇
眼科学   792篇
药学   1364篇
  3篇
中国医学   349篇
肿瘤学   1334篇
  2024年   61篇
  2023年   454篇
  2022年   292篇
  2021年   496篇
  2020年   472篇
  2019年   242篇
  2018年   808篇
  2017年   805篇
  2016年   863篇
  2015年   855篇
  2014年   793篇
  2013年   1086篇
  2012年   1427篇
  2011年   2398篇
  2010年   1424篇
  2009年   1151篇
  2008年   1416篇
  2007年   1415篇
  2006年   1219篇
  2005年   1379篇
  2004年   2468篇
  2003年   2173篇
  2002年   1540篇
  2001年   1184篇
  2000年   635篇
  1999年   598篇
  1998年   515篇
  1997年   477篇
  1996年   230篇
  1995年   166篇
  1994年   167篇
  1993年   199篇
  1992年   189篇
  1991年   121篇
  1990年   130篇
  1989年   93篇
  1988年   79篇
  1987年   85篇
  1986年   54篇
  1985年   33篇
  1984年   28篇
  1983年   21篇
  1982年   24篇
  1981年   23篇
  1980年   17篇
  1979年   18篇
  1978年   18篇
  1975年   16篇
  1974年   22篇
  1968年   18篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
The role of surgery as an additional risk in transmitting post-transfusion hepatitis was investigated in a retrospective study on acute hepatitis occurring in 77 transfused patients, 293 transfused and operated patients and 243 hepatitis cases with history of surgery without transfusion.Hepatitis A patients admitted to the same centres in the same period were utilized as controls. In transfused patients the percentage of NANB hepatitis was higher than that of type B (61.0% vs. 36.4%), while in the operated not transfused group the percentage of type B was twice that of type NANB (63.4% vs. 32.5%).In transfused and operated cases intermediate values were observed. The age-adjusted measures of association between exposures and the different hepatitis types showed a lack of effect of transfusion and a dominant role of surgery in transmitting type B hepatitis. In contrast, NANB post-transfusional cases were actually a mixture of post-transfusional and post-surgical cases, since both these exposures were found to be significantly associated with the disease.Our results suggest that studies on the incidence and the etiology of post-transfusion hepatitis should take into account the risk of surgical exposure which might have occurred.Corresponding author.  相似文献   
62.
Metadata, the term, may be new but metadata, the concept, is not new. For purposes of this paper, the term metadata is defined as the data used to define, store, retrieve, combine, analyze, and present the data values (the “real” data, so to speak). As clinical research studies get larger, it becomes desirable to use automated managers of the metadata. The Program on the Surgical Control of the Hyperlipidemias (POSCH), a national multiclinic clinical trial, manages most of its metadata manually but has been experimenting with ways to more fully automate them. Its Information Management System (IMS) is described with special emphasis on how it manages the metadata. The case is presented for further automation and standardization of metadata in large clinical research studies so that costs can be contained and smaller increments of “progress” can be measured. The concept of a Metadatabase Management System (MDBMS) is developed and illustrated using POSCH.  相似文献   
63.
人工流产术前宫颈及子宫内膜麻醉的镇痛效果探讨   总被引:1,自引:0,他引:1  
目的 探讨宫颈与子宫内膜两部位联合麻醉、普鲁卡因与利多卡因两药物配合应用在人工流产术中的镇痛效果。方法 人工流产术前对麻醉组 10 6例行普鲁卡因宫颈浸润麻醉和利多卡因子宫内膜表面麻醉。术中记录受术者腹痛程度、无阻力插入宫颈内口的扩张器号、出血量、人流综合征例数等指标。按照世界卫生组织规定疼痛标准及人工流产综合征反应进行评价 ,同期选择按传统机械扩宫法 10 4例做对照。结果 麻醉组镇痛有效率95 3% ,宫口松驰有效率 95 3% ,人流综合征无 1例发生。两组比较P均 <0 0 0 1。两组出血量比较无差异 ,无利多卡因毒性反应发生。结论 人工流产术前普鲁卡因宫颈浸润麻醉和利多卡因子宫内膜表面麻醉镇痛效果显著 ,可大大降低人流综合征的发生 ,避免利多卡因的毒性反应  相似文献   
64.
High-risk combinations of recipient and graft characteristics are poorly defined for liver retransplantation (reLT) in the current era. We aimed to develop a risk model for survival after reLT using data from the European Liver Transplantation Registry, followed by internal and external validation. From 2006 to 2016, 85 067 liver transplants were recorded, including 5581 reLTs (6.6%). The final model included seven predictors of graft survival: recipient age, model for end-stage liver disease score, indication for reLT, recipient hospitalization, time between primary liver transplantation and reLT, donor age, and cold ischemia time. By assigning points to each variable in proportion to their hazard ratio, a simplified risk score was created ranging 0–10. Low-risk (0–3), medium-risk (4–5), and high-risk (6–10) groups were identified with significantly different 5-year survival rates ranging 56.9% (95% CI 52.8–60.7%), 46.3% (95% CI 41.1–51.4%), and 32.1% (95% CI 23.5–41.0%), respectively (< 0.001). External validation showed that the expected survival rates were closely aligned with the observed mortality probabilities. The Retransplantation Risk Score identifies high-risk combinations of recipient- and graft-related factors prognostic for long-term graft survival after reLT. This tool may serve as a guidance for clinical decision-making on liver acceptance for reLT.  相似文献   
65.
66.
EBV-positive and EBV-negative posttransplant lymphoproliferative disorders (PTLDs) arise in different immunovirological contexts and might have distinct pathophysiologies. To examine this hypothesis, we conducted a multicentric prospective study with 56 EBV-positive and 39 EBV-negative PTLD patients of the K-VIROGREF cohort, recruited at PTLD diagnosis and before treatment (2013–2019), and compared them to PTLD-free Transplant Controls (TC, n = 21). We measured absolute lymphocyte counts (n = 108), analyzed NK- and T cell phenotypes (n = 49 and 94), and performed EBV-specific functional assays (n = 16 and 42) by multiparameter flow cytometry and ELISpot-IFNγ assays (n = 50). EBV-negative PTLD patients, NK cells overexpressed Tim-3; the 2-year progression-free survival (PFS) was poorer in patients with a CD4 lymphopenia (CD4+<300 cells/mm3, p <  .001). EBV-positive PTLD patients presented a profound NK-cell lymphopenia (median = 60 cells/mm3) and a high proportion of NK cells expressing PD-1 (vs. TC, p = .029) and apoptosis markers (vs. TC, p < .001). EBV-specific T cells of EBV-positive PTLD patients circulated in low proportions, showed immune exhaustion (p = .013 vs. TC) and poorly recognized the N-terminal portion of EBNA-3A viral protein. Altogether, this broad comparison of EBV-positive and EBV-negative PTLDs highlight distinct patterns of immunopathological mechanisms between these two diseases and provide new clues for immunotherapeutic strategies and PTLD prognosis.  相似文献   
67.
ObjectiveTo validate a Russian-language version of the World Health Organization’s Alcohol Use Disorders Identification Test (AUDIT).MethodsWe invited 2173 patients from 21 rural and urban primary health-care centres in nine Russian regions to participate in the study (143 declined and eight were excluded). In a standardized interview, patients who had consumed alcohol in the past 12 months provided information on their sociodemographic characteristics and completed the Russian AUDIT, the Kessler Psychological Distress Scale and the Composite International Diagnostic Interview to identify problem drinking and alcohol use disorders. We assessed the feasibility of administering the test, its internal consistency and its ability to predict hazardous drinking and alcohol use disorders in primary health care in the Russian Federation.FindingsOf the 2022 patients included in the study, 1497 were current drinkers with Russian AUDIT scores. The test was internally consistent with good psychometric properties (Cronbach’s α : 0.842) and accurately predicted alcohol use disorders and other outcomes (area under the curve > 75%). A three-item short form of the test correlated well with the full instrument and had similar predictive power (area under the curve > 80%). We determined sex-specific thresholds for all outcomes, as non-specific thresholds resulted in few women being identified.ConclusionWith the validated Russian AUDIT, there is no longer a barrier to introducing screening and brief interventions into primary health care in the Russian Federation to supplement successful alcohol control policies.  相似文献   
68.
Nucleos(t)ide analogs (NAs) cannot completely suppress the risk of hepatocellular carcinoma (HCC) in patients with chronic hepatitis B (CHB). This study aimed to identify the risk factors for HCC development in naïve CHB patients treated with current NA. Patients receiving NA (n = 905) were recruited retrospectively from the 17 hospitals of the Japanese Red Cross Liver Study Group. All treatment-naïve patients had been receiving current NA continuously for more than 1 year until the end of the follow-up. We analyzed the accuracy of predictive risk score using the area under receiver operating characteristic curve. The albumin–bilirubin (ALBI) score was significantly improved by NA therapy (−0.171 ± 0.396; p < 0.001 at Week 48). A total of 72 (8.0%) patients developed HCC over a median follow-up of 6.2 (1.03–15.7) years. An independent predictive factor of HCC development was older age, cirrhosis, lower platelet counts at baseline and ALBI score, and alpha-fetoprotein (AFP) at 1 year after NA therapy according to multivariate analysis. The accuracy was assessed using the PAGE-B, mPAGE-B, aMAP, APA-B, and REAL-B scores that included these factors. Discrimination was generally acceptable for these models. aMAP and REAL-B demonstrated high discrimination with 0.866/0.862 and 0.833/0.859 for 3- and 5-year prediction from the status of 1 year after NA therapy, respectively. Baseline age and platelet count, as well as ALBI and AFP one year after NA, were useful for stratifying carcinogenesis risk. The aMAP and REAL-B scores were validated with high accuracy in Japanese CHB patients.  相似文献   
69.
贵阳地区1?055例骨密度检测分析   总被引:13,自引:0,他引:13  
采用日本阿洛卡公司双能量骨密测量仪,选择受检者桡骨远端1/3处为测量点,对贵阳地区1055例人群成人桡骨的骨密度进行测量,取得不同性别各年龄段的骨密度值,同时计算出贵阳地区成人桡骨各年龄段的骨密度均值及标准偏差。  相似文献   
70.
The aim of the present study was to investigate the nature and prevalence of nonspecific somatic symptoms, pain and catastrophizing in children with Heritable Connective Tissue Disorders (HCTD), and to determine their association with disability. This observational, multicenter study included 127 children, aged 4–18 years, with Marfan syndrome (MFS) (59%), Loeys-Dietz syndrome (LDS) (8%), Ehlers-Danlos syndromes (EDS) (12%) and hypermobile Ehlers-Danlos syndrome (hEDS) (23%). The assessments included the Children's Somatization Inventory or parent proxy (CSI, PCSI), pain visual-analogue scale (VAS), SUPERKIDZ body diagram, Pain Catastrophizing Scale Child or parent proxy (PCS-C, PCS-P) and Childhood Health Assessment Questionnaire (CHAQ-30). Data from children aged ≥8 years were compared to normative data. In children ≥ 8 years (n = 90), pain was present in 59%, with a median of 4 (IQR = 3–9) pain areas. Compared to normative data, the HCTD group reported significantly higher on the CSI (p ≤ 0.001, d = 0.85), VAS pain intensity (p ≤ 0.001, d = 1.22) and CHAQ-30 (p ≤ 0.001, d = 1.16) and lower on the PCS-C (p = 0.017, d = −0.82) and PCS-P (p ≤ 0.001, d = −0.49). The intensity of nonspecific somatic symptoms and pain explained 45% of the variance in disability (r2 = 0.45 F(2,48) = 19.70, p ≤ 0.001). In children ≤ 7 years (n = 37), pain was present in 35% with a median of 5(IQR = 1–13) pain areas. The mean(SD) VAS scores for pain intensity was 1.5(2.9). Functional disability was moderately correlated to the number of pain areas (r = 0.56, p ≤ 0.001), intensity of nonspecific somatic symptoms (r = 0.63, p ≤ 0.001) and pain (r = 0.83, p ≤ 0.001). In conclusion, this study supports the need for comprehensive assessment of nonspecific somatic symptoms, pain, and disability in children with HCTD to allow tailored treatment.  相似文献   
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