全文获取类型
| 收费全文 | 2444050篇 |
| 免费 | 192416篇 |
| 国内免费 | 9898篇 |
专业分类
| 耳鼻咽喉 | 31515篇 |
| 儿科学 | 79625篇 |
| 妇产科学 | 67120篇 |
| 基础医学 | 347214篇 |
| 口腔科学 | 67561篇 |
| 临床医学 | 228766篇 |
| 内科学 | 486291篇 |
| 皮肤病学 | 54513篇 |
| 神经病学 | 202956篇 |
| 特种医学 | 93503篇 |
| 外国民族医学 | 624篇 |
| 外科学 | 358758篇 |
| 综合类 | 55561篇 |
| 现状与发展 | 3篇 |
| 一般理论 | 855篇 |
| 预防医学 | 206710篇 |
| 眼科学 | 53228篇 |
| 药学 | 176695篇 |
| 11篇 | |
| 中国医学 | 5070篇 |
| 肿瘤学 | 129785篇 |
出版年
| 2019年 | 19604篇 |
| 2018年 | 28319篇 |
| 2017年 | 21526篇 |
| 2016年 | 24354篇 |
| 2015年 | 27598篇 |
| 2014年 | 37910篇 |
| 2013年 | 58216篇 |
| 2012年 | 76069篇 |
| 2011年 | 81048篇 |
| 2010年 | 48543篇 |
| 2009年 | 45644篇 |
| 2008年 | 74366篇 |
| 2007年 | 78869篇 |
| 2006年 | 80036篇 |
| 2005年 | 77451篇 |
| 2004年 | 73767篇 |
| 2003年 | 70867篇 |
| 2002年 | 67926篇 |
| 2001年 | 110991篇 |
| 2000年 | 114066篇 |
| 1999年 | 95770篇 |
| 1998年 | 28456篇 |
| 1997年 | 25493篇 |
| 1996年 | 26100篇 |
| 1995年 | 25666篇 |
| 1994年 | 24023篇 |
| 1993年 | 22511篇 |
| 1992年 | 78006篇 |
| 1991年 | 76127篇 |
| 1990年 | 73412篇 |
| 1989年 | 69778篇 |
| 1988年 | 64837篇 |
| 1987年 | 63588篇 |
| 1986年 | 60413篇 |
| 1985年 | 58052篇 |
| 1984年 | 44237篇 |
| 1983年 | 37302篇 |
| 1982年 | 23037篇 |
| 1981年 | 20592篇 |
| 1979年 | 40075篇 |
| 1978年 | 28995篇 |
| 1977年 | 24087篇 |
| 1976年 | 22940篇 |
| 1975年 | 23704篇 |
| 1974年 | 28486篇 |
| 1973年 | 27523篇 |
| 1972年 | 25403篇 |
| 1971年 | 23524篇 |
| 1970年 | 21684篇 |
| 1969年 | 20090篇 |
排序方式： 共有10000条查询结果，搜索用时 31 毫秒
61.
62.
Prevalence of HER2 Expression and Its Correlation with Clinicopathological Parameters in Gastric or Gastroesophageal Junction Adenocarcinoma in North-East Indian Population 
下载免费PDF全文
下载免费PDF全文 Partha S RoyTomar NyoduMunlima HazarikaB J SaikiaC BhuyanAmit InamdarC W NyutheB BorthakurJ D Sharma 《Asian Pacific journal of cancer prevention》2019,20(4):1139-1145
Objective: Human epidermal growth factor receptor 2 (erbb2/HER2) overexpression, has now been implicatedin advanced gastric and gastroesophageal junction cancers. The study was conducted to determine the rate of HER2positivity in patients with locally advanced or metastatic gastric and gastroesophageal adenocarcinoma in North-EastIndia and to assess the impact of various demographic and clinical parameters on HER2 positivity. Methods: A total of68 patients of age >18 years of gastric and gastroesophageal adenocarcinoma diagnosed on histopathological examinationfrom September 2016 to February 2018 at Dr B Borooah Cancer Institute, Assam were enrolled for the observational(epidemiological) study. All patients were subjected to the HER2 immunohistochemistry test using a FDA-approved,standardized test kit. HER2 expression was correlated with various demographic and clinicopathological parameters.Results: The overall rate of HER2 positivity in the population studied was 56% (n=38). The rate was non-significantlyhigher in male, older age group (>60 years) and Hindu population. Similarly, HER2 positivity rate was higher in patientswith well differentiated histology and was more common in patients with stage II and III diseases, but neither of theassociations is statistically significant. HER2 positivity rate was significantly higher in proximal and in GEJ tumours(56% versus 44%, P=0.002). Conclusion: HER2 overexpression was evident in 56% of the North-East Indian patientswith locally advanced and metastatic gastric and gastroesophageal adenocarcinoma. The overexpression correlatedsignificantly with primary tumour site. Routine testing of gastric and gastroesophageal tumours for HER2 expressionis recommended to provide a therapeutic advantage in Indian patients. 相似文献
63.
Alexandra B. Morshed Rachel G. Tabak Cynthia D. Schwarz Debra Haire-Joshu 《Journal of nutrition education and behavior》2019,51(2):237-244
Objective
To examine whether a healthy weight intervention embedded in the Parents as Teachers (PAT) home visiting program, which was previously found to improve mothers’ body mass index (BMI) and obesity-related behaviors, changed the BMI of preschool children or maternal feeding practices.Methods
This stratified randomized trial included preschool-aged children at risk for overweight whose mothers were overweight or had obesity (n?=?179). The Healthy Eating and Active Living Taught at Home (HEALTH) intervention was based on the Diabetes Prevention Program. Differences were examined using repeated-measures mixed-ANOVA models.Results
Compared with PAT usual care, the HEALTH intervention had no effect on children's BMI or maternal feeding practices. However, combined analyses showed that children's BMI percentile decreased (P??=?.007), BMI z-scores were maintained (P??=?.19), and 3 of 8 feeding practices improved over time (P < .05).Conclusions and Implications
Additional research is needed to assess the effectiveness of PAT to prevent preschool-age obesity using rigorous designs (eg, group-randomized trials) and to identify its active components. HEALTH is ready to be scaled up to prevent maternal weight gain through embedding within the national PAT program. 相似文献64.
Elizabeth D. Krebs Robert B. Hawkins J. Hunter Mehaffey Clifford E. Fonner Alan M. Speir Mohammed A. Quader Jeffrey B. Rich Leora T. Yarboro Nicholas R. Teman Gorav Ailawadi 《The Journal of thoracic and cardiovascular surgery》2019,157(4):1533-1542.e2
Objectives
Expedient extubation after cardiac surgery has been associated with improved outcomes, leading to postoperative extubation frequently during overnight hours. However, recent evidence in a mixed medical-surgical intensive care unit population demonstrated worse outcomes with overnight extubation. This study investigated the impact of overnight extubation in a statewide, multicenter Society of Thoracic Surgeons database.Methods
Records from 39,812 patients undergoing coronary artery bypass grafting or valve operations (2008-2016) and extubated within 24 hours were stratified according to extubation time between 06:00 and 18:00 (day) or between 18:00 and 6:00 (overnight). Outcomes including reintubation, mortality, and composite morbidity-mortality were evaluated using hierarchical regression models adjusted for Society of Thoracic Surgeons predictive risk scores. To further analyze extubation during the night, a subanalysis stratified patients into 3 groups: 06:00 to 18:00, 18:00 to 24:00, and 24:00 to 06:00.Results
A total of 20,758 patients were extubated overnight (52.1%) and were slightly older (median age 66 vs 65 years, P < .001) with a longer duration of ventilation (4 vs 7 hours, P < .001). Day and overnight extubation were associated with equivalent operative mortality (1.7% vs 1.7%, P = .880), reintubation (3.7% vs 3.4%, P = .141), and composite morbidity-mortality (8.2% vs 8.0%, P = .314). After risk adjustment, overnight extubation was not associated with any difference in reintubation, mortality, or composite morbidity-mortality. On subanalysis, those extubated between 24:00 and 06:00 exhibited increased composite morbidity-mortality (odds ratio, 1.18; P = .001) but no difference in reintubation or mortality.Conclusions
Extubation overnight was not associated with increased mortality or reintubation. These results suggest that in the appropriate clinical setting, it is safe to routinely extubate cardiac surgery patients overnight. 相似文献65.
66.
Notfall + Rettungsmedizin - 相似文献
67.
68.
Whitney S. Brandt Wanpu Yan Jian Zhou Kay See Tan Joseph Montecalvo Bernard J. Park Prasad S. Adusumilli James Huang Matthew J. Bott Valerie W. Rusch Daniela Molena William D. Travis Mark G. Kris Jamie E. Chaft David R. Jones 《The Journal of thoracic and cardiovascular surgery》2019,157(2):743-753.e3
Objective
Comparative survival between neoadjuvant chemotherapy and adjuvant chemotherapy for patients with cT2-4N0-1M0 non–small cell lung cancer has not been extensively studied.Methods
Patients with cT2-4N0-1M0 non–small cell lung cancer who received platinum-based chemotherapy were retrospectively identified. Exclusion criteria included stage IV disease, induction radiotherapy, and targeted therapy. The primary end point was disease-free survival. Secondary end points were overall survival, chemotherapy tolerance, and ability of Response Evaluation Criteria In Solid Tumors response to predict survival. Survival was estimated using the Kaplan–Meier method, compared using the log-rank test and Cox proportional hazards models, and stratified using matched pairs after propensity score matching.Results
In total, 330 patients met the inclusion criteria (n = 92/group after propensity-score matching; median follow-up, 42 months). Five-year disease-free survival was 49% (95% confidence interval, 39-61) for neoadjuvant chemotherapy versus 48% (95% confidence interval, 38-61) for adjuvant chemotherapy (P = .70). On multivariable analysis, disease-free survival was not associated with neoadjuvant chemotherapy or adjuvant chemotherapy (hazard ratio, 1.1; 95% confidence interval, 0.64-1.90; P = .737), nor was overall survival (hazard ratio, 1.21; 95% confidence interval, 0.63-2.30; P = .572). The neoadjuvant chemotherapy group was more likely to receive full doses and cycles of chemotherapy (P = .014/0.005) and had fewer grade 3 or greater toxicities (P = .001). Response Evaluation Criteria In Solid Tumors response to neoadjuvant chemotherapy was associated with disease-free survival (P = .035); 15% of patients receiving neoadjuvant chemotherapy (14/92) had a major pathologic response.Conclusions
Timing of chemotherapy, before or after surgery, is not associated with an improvement in overall or disease-free survival among patients with cT2-4N0-1M0 non–small cell lung cancer who undergo complete surgical resection. 相似文献69.
70.
Metabolism describes the series of chemical reactions that are concerned with the provision of energy to biological systems. They may be divided into reactions involved in energy yield (catabolism: demand exceeds supply), and energy storage (anabolism: supply exceeds demand). Regulation of these pathways is critical for homeostasis, and derangements in metabolism are seen in a wide variety of pathological processes. Understanding metabolism is key to the treatment of many diseases, notably diabetes, as well as underpinning clinical nutritional support. 相似文献