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   1598篇
  免费   93篇
  国内免费   13篇
耳鼻咽喉   7篇
儿科学   80篇
妇产科学   28篇
基础医学   166篇
口腔科学   28篇
临床医学   186篇
内科学   415篇
皮肤病学   24篇
神经病学   141篇
特种医学   19篇
外科学   180篇
综合类   10篇
预防医学   166篇
眼科学   22篇
药学   133篇
中国医学   10篇
肿瘤学   89篇
  2024年   1篇
  2023年   15篇
  2022年   15篇
  2021年   72篇
  2020年   38篇
  2019年   59篇
  2018年   68篇
  2017年   43篇
  2016年   48篇
  2015年   51篇
  2014年   64篇
  2013年   87篇
  2012年   144篇
  2011年   142篇
  2010年   86篇
  2009年   71篇
  2008年   106篇
  2007年   120篇
  2006年   113篇
  2005年   85篇
  2004年   73篇
  2003年   64篇
  2002年   80篇
  2001年   5篇
  2000年   8篇
  1999年   6篇
  1998年   9篇
  1997年   3篇
  1996年   3篇
  1995年   3篇
  1994年   1篇
  1993年   1篇
  1992年   3篇
  1991年   3篇
  1990年   1篇
  1989年   4篇
  1987年   1篇
  1986年   1篇
  1985年   1篇
  1984年   1篇
  1983年   1篇
  1982年   2篇
  1981年   1篇
  1979年   1篇
排序方式: 共有1704条查询结果,搜索用时 968 毫秒
1.
2.
Objective Consensus that enhanced teamwork is necessary for efficient and effective primary care delivery is growing. We sought to identify how electronic health records (EHRs) facilitate and pose challenges to primary care teams as well as how practices are overcoming these challenges.Methods Practices in this qualitative study were selected from those recognized as patient-centered medical homes via the National Committee for Quality Assurance 2011 tool, which included a section on practice teamwork. We interviewed 63 respondents, ranging from physicians to front-desk staff, from 27 primary care practices ranging in size, type, geography, and population size.Results EHRs were found to facilitate communication and task delegation in primary care teams through instant messaging, task management software, and the ability to create evidence-based templates for symptom-specific data collection from patients by medical assistants and nurses (which can offload work from physicians). Areas where respondents felt that electronic medical record EHR functionalities were weakest and posed challenges to teamwork included the lack of integrated care manager software and care plans in EHRs, poor practice registry functionality and interoperability, and inadequate ease of tracking patient data in the EHR over time.Discussion Practices developed solutions for some of the challenges they faced when attempting to use EHRs to support teamwork but wanted more permanent vendor and policy solutions for other challenges.Conclusions EHR vendors in the United States need to work alongside practicing primary care teams to create more clinically useful EHRs that support dynamic care plans, integrated care management software, more functional and interoperable practice registries, and greater ease of data tracking over time.  相似文献   
3.
Background Transarterial chemoemobolization (TACE) is commonly used to treat metastatic carcinoid tumors; however, the management of progressive disease is less clear. We sought to determine if patients with disease progression after TACE would benefit from repeat TACE. Methods The records of 27 patients undergoing repeat TACE for radiologic or symptomatic progression after TACE for metastatic carcinoid were reviewed and compared to 122 undergoing first TACE. Overall and progression-free survivals were estimated by the Kaplan–Meier method. Results Mean disease-free interval after first TACE was 11.8 months. Radiologic response was observed in 61% compared to 82% after first TACE (p = 0.058); hormone response in 64% compared to 80% (p = 0.159); and symptomatic response in 77% compared to 92% (p = 0.053). The complication rate after repeat TACE was lower than after first TACE (p = 0.03). Median overall survival was similar after repeat (28.1 months) and first TACE (33.3 months) (p = 0.53). Progression-free survival was shorter after repeat TACE but not significantly so. No factor examined could predict survival after repeat TACE. Conclusion Repeat TACE for patients with hepatic carcinoid metastases failing first TACE or having evidence of disease progression is safe and offers a viable treatment option. Presented at the 48th Annual Meeting of The Society for Surgery of the Alimentary Tract, Washington, DC, May, 2007.  相似文献   
4.
It's all about sex: gender, lung development and lung disease.   总被引:1,自引:0,他引:1  
Accumulating evidence suggests that gender affects the incidence, susceptibility and severity of several lung diseases. Gender also influences lung development and physiology. Data from both human and animal studies indicate that sex hormones might contribute to disease pathogenesis or serve as protective factors, depending on the disease involved. In this review, the influence of gender and sex hormones on lung development and pathology will be discussed, with specific emphasis on pulmonary fibrosis, asthma and cancer.  相似文献   
5.
6.
Breast carcinoma is a genetically and phenotypically heterogeneous disease and is frequently associated with nonrandom chromosomal alterations. The aim of this study was to investigate the numerical aberrations of chromosome 20 in breast cancer. The observed chromosome-specific numerical abnormalities were evaluated along with the established clinicopathological parameters, the immunohistochemical expression of ER, PR, p53, c-erbB-2, Ki-67 and patients' survival. Nonisotopic in situ hybridization was applied to interphase cell nuclei on paraffin embedded tissue sections. Polysomy of chromosome 20 was the prevalent alteration in 45 of 50 (90%), monosomy in 2 of 50 (4%) and disomy in 3 of 50 (6%) cases. Invasive ductal carcinomas displayed a higher percentage of polysomy than lobular ones. A statistical significant association was demonstrated between Ki-67 immunohistochemical expression and polysomy of chromosome 20. Disomy was inversely correlated with Ki-67, while monosomy was suggestively associated with PR positive expression. Among the patients, those with the highest levels of polysomy showed the worst survival. In conclusion, the gain of chromosome 20 is the prevalent aberration in patients with breast carcinomas and may be useful prognostic marker in breast cancer.  相似文献   
7.
Tissue inhibitor of metalloproteinase-1 (TIMP-1) has emerged as a multifunctional protein with the contrasting activities of inhibiting tissue-degrading enzymes and promoting cellular growth. In an attempt to elucidate the clinical significance of TIMP-1 in breast cancer, the expression of TIMP-1 mRNA was evaluated in 117 invasive breast carcinomas by mRNA in situ hybridization, in correlation with clinicopathological parameters, immunohistochemical prognostic factors (Ki-67, c-erb-B-2, bcl-2) and clinical outcome. TIMP-1 was detected in stromal cells in areas within the tumours and at the tumour margin. High TIMP-1 mRNA expression in the marginal portion of the tumours was significantly correlated with lymph node metastasis (p<0.05) and c-erbB-2 expression (p<0.05). On the other hand, increased TIMP-1 mRNA expression within the tumours showed a statistically significant correlation with ER detection (p<0.01). Multivariate analysis revealed worse survival for patients with high TIMP-1 mRNA expression in the marginal portion of the tumours; the subgroup of these patients co-expressing high levels of TIMP-1 mRNA within the tumours as well had even worse survival (p=0.042). In conclusion, our data support the multifunctional role of TIMP-1, particularly its growth-promoting activity, on the basis of its significant correlation with lymph node metastasis and adverse prognosis. In addition to the latter property, a probable association of TIMP-1 with tumour cell differentiation is suggested by its topographical correlation with ER detection.  相似文献   
8.
The excitatory amino acids l-glutamate and l-aspartate are believed to be utilized as neurotransmitters by the pyramidal neurons in the mammalian cerebral cortex. These cells can be recognized early in development, while glutamate might play an important part in the maturation and plasticity of the cortex. Here, we used light and electron microscopic immunocytochemistry to study the time of appearance and maturation of glutamate and aspartate in neurons of the rat visual cortex. Glutamate- and aspartate-immunoreactive cells were first detected in deep cortical layers at postnatal day 3. During the next 3 weeks, labelled neurons were observed progressively in more superficial layers, but did not demonstrate their adult pattern of distribution until postnatal week 4. Electron microscopic analysis showed that glutamate- and aspartate-labelled neurons gradually develop their cytological and synaptic features during the first 4 postnatal weeks, with this process of differentiation originating in the deep cortical layers and progressively extending to the superficial layers. These findings suggest that cortical pyramidal neurons begin to express detectable levels of transmitter glutamate and/or aspartate after they have completed their migration. Their neurochemical differentiation follows an inside-out pattern similar to the pattern described for the genesis and morphological differentiation of this population of cortical neurons.  相似文献   
9.
The aim of this study was to determine the frequency of hepatitis E virus (HEV) infection in a population of Greek adults with community-acquired (sporadic) non-A, non-B hepatitis found to be seronegative for antibodies to hepatitis C virus (anti-HCV). All patients admitted to the Liver Unit of Western Attica General Hospital and diagnosed as having acute community-acquired non-A, non-B hepatitis between February, 1986, and May, 1990, were enrolled in follow up studies (n = 66). Nineteen patients with HCV infection and 11 patients with acute non-A, non-B, non-C hepatitis that progressed to chronicity were excluded. Convalescent sera were tested for antibody to HEV (anti-HEV) by a fluorescent antibody blocking assay in 33 of 36 eligible patients. One of the 33 (3%) patients was found to be positive for anti-HEV. Anti-HEV testing of all 20 available serum specimens from this patient showed evidence of anti-HEV seroconversion at the fourth week after the onset of hepatitis. The patient had not travelled abroad or within Greece or had not had apparent contact with people from foreign countries for the previous 3 months. These data show that HEV infection is not a major cause of community-acquired non-A, non-B hepatitis in Greece. However, the reported case of HEV hepatitis suggests that HEV may retain a low endemicity in Greece. More extensive seroprevalence studies are needed for an accurate estimation of the extent of HEV infection in the southeastern European countries. © 1994 Wiiey-Liss, Inc.  相似文献   
10.
Introduction: The effects of “aggressive” neonatal feeding policies of very preterm neonates (VPN) and the risk of metabolic syndrome later in life remain questionable. We aimed to evaluate the effect of our “aggressive” nutrition policies of VPN during hospitalisation on body mass index (BMI) at ages 2 and 8 years. Materials and Methods: Eighty four VPN, who received “aggressive” nutrition during hospitalisation in an effort to minimise postnatal growth restriction (PGR) (group A), and 62 term neonates, as controls (group B), were enrolled in the study. Group A was further divided in four subgroups depending on the type (A1: fortified expressed breast milk and preterm formula; A2: exclusively preterm formula) and quantity of milk received (A3: maximum feeds 180–210 mL/kg/day; A4: maximum feeds 210 and up to 260 mL/kg/day). BMI was calculated at ages 2 and 8 years and plotted on the centile charts. Results: There was no significant difference in BMI between groups A and B at 2 and 8 years, respectively, in both absolute BMI values and their centile chart distribution. There was no significant difference in BMI at 2 and 8 years either between subgroups A1 and A2 or between subgroups A3 and A4. Conclusions: “Aggressive” and individualised feeding policy for VPN did not affect the BMI and obesity rates at ages of 2 and 8 years in our study population. The type and quantity of milk feeds had no impact on their BMI at school age. Further larger studies are needed to confirm our results.  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