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   14304篇
  免费   677篇
  国内免费   83篇
耳鼻咽喉   182篇
儿科学   279篇
妇产科学   279篇
基础医学   1682篇
口腔科学   716篇
临床医学   1429篇
内科学   3299篇
皮肤病学   241篇
神经病学   1181篇
特种医学   313篇
外科学   2190篇
综合类   82篇
一般理论   14篇
预防医学   1126篇
眼科学   263篇
药学   802篇
中国医学   52篇
肿瘤学   934篇
  2024年   15篇
  2023年   142篇
  2022年   283篇
  2021年   525篇
  2020年   313篇
  2019年   410篇
  2018年   476篇
  2017年   359篇
  2016年   360篇
  2015年   418篇
  2014年   599篇
  2013年   762篇
  2012年   1224篇
  2011年   1220篇
  2010年   685篇
  2009年   626篇
  2008年   1003篇
  2007年   979篇
  2006年   871篇
  2005年   862篇
  2004年   738篇
  2003年   620篇
  2002年   582篇
  2001年   74篇
  2000年   66篇
  1999年   86篇
  1998年   117篇
  1997年   76篇
  1996年   71篇
  1995年   60篇
  1994年   48篇
  1993年   45篇
  1992年   37篇
  1991年   32篇
  1990年   16篇
  1989年   14篇
  1988年   16篇
  1987年   22篇
  1986年   26篇
  1985年   19篇
  1984年   17篇
  1983年   9篇
  1982年   10篇
  1981年   18篇
  1980年   18篇
  1979年   13篇
  1977年   10篇
  1975年   11篇
  1974年   11篇
  1969年   6篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Loop ileostomy closure after colorectal surgery is often associated with Postoperative ileus, with an incidence between 13–20%. The aim of this study is to evaluate the efficacy and safety of preoperative stimulation of the efferent loop with probiotics prior to ileostomy closure in patients operated on for colorectal carcinoma. For this, a prospective, randomized, double-blind, controlled study is designed. All patients who underwent surgery for colorectal carcinoma with loop ileostomy were included. Randomized and divided into two groups, 34 cases and 35 controls were included in the study. Postoperative ileus, the need for nasogastric tube insertion, the time required to begin tolerating a diet, restoration of bowel function, and duration of hospital stay were evaluated. The incidence of Postoperative ileus was similar in both groups, 9/34 patients stimulated with probiotics and 10/35 in the control group (CG) with a p = 0.192. The comparative analysis showed a direct relationship between Postoperative ileus after oncological surgery and Postoperative ileus after reconstruction surgery, independently of stimulation. Postoperative ileus after closure ileostomy is independent of stimulation of the ileostomy with probiotics through the efferent loop. There seem to be a relationship between Postoperative ileus after reconstruction and the previous existence of Postoperative ileus after colorectal cancer surgery.  相似文献   
92.
PurposeThis study examines sociodemographic patterns of exclusive/dual/polytobacco use among U.S. high school students using multiple national surveys.MethodsUsing three national youth surveys (Population Assessment of Tobacco and Health [PATH] Wave 4 [2016–2017], 2017 Youth Risk Behavior Survey, and 2017 National Youth Tobacco Survey), we classified tobacco products into four groups: (1) electronic nicotine delivery systems (ENDS), (2) conventional cigarettes (CCs), (3) other combustible tobacco products, and (4) smokeless tobacco products. We created 16 categories of non/exclusive/dual/polytobacco use within the past 30 days using the four product groups and calculated weighted population prevalence by sex and race/ethnicity (all surveys) and parental education and income (PATH), based on variable availability.ResultsThe results from 9,331, 12,407, and 9,699 high school students in PATH, Youth Risk Behavior Survey, and National Youth Tobacco Survey, respectively, largely agreed and pointed to similar conclusions. ENDS was the most prevalent exclusive use product (3.8%–5.2% across surveys), with CCs falling to second or third (1.2%–2.0% across surveys). By sex, exclusive, dual, and poly smokeless tobacco product use were more common for males, whereas exclusive CC use was more common for females. By race/ethnicity, non-Hispanic Whites had a higher prevalence of exclusive ENDS use and ENDS/CC dual use than non-Hispanic Blacks. As income and parental education levels increased from low to high, the prevalence of exclusive CC use decreased, whereas the prevalence of exclusive ENDS use increased.ConclusionUnderstanding sociodemographic patterns of tobacco use can help identify groups who may be at greater risk for tobacco-related health outcomes.  相似文献   
93.
Neurosurgical Review - The current literature regarding surgical treatment for tumors in the sphenopetroclival (SPC) region is merely scarce. Through a comprehensive literature review, we...  相似文献   
94.
BackgroundRevision total knee arthroplasty (rTKA) rates are increasing in younger patients. Few studies have assessed outcomes of initial aseptic rTKA performed for younger patients compared with traditional-aged patients.MethodsA detailed medical record review was performed to identify patient demographics, medical comorbidities, surgical rTKA indications, timing from index TKA to rTKA, subsequent reoperation rates, component rerevision rates, and salvage procedures for 147 young patients (158 knees) aged 55 years and younger and for a traditional older cohort of 276 patients (300 knees) between 60 and 75 years. Univariate analysis was performed to assess differences in these primary variables, and a log-rank test was used to estimate 5-year implant survival based on either reoperation or component revision and salvage procedures.ResultsYounger TKA patients were more likely to undergo initial aseptic rTKA within 2 years of their primary TKA (52.5% vs 29.0%, P < .001) and were more likely to undergo early reoperation (17.7% vs 9.7%, P = .02) or component rerevision (11.4% vs 6.0%, P < .05) after rTKA. Infection and extensor mechanism complications were more commonly noted in younger patients. Estimated 5-year survival was also lower for both reoperation (59.4% vs 65.7%, P = .02) and component rerevision or salvage (65.8% vs 80.1%, P = .02).ConclusionEarly reoperation and component re-rTKA were performed nearly twice as often in younger rTKA than traditional-aged TKA patients. Care should be given to reduce perioperative infection and extensor mechanism failures after rTKA in younger patients.  相似文献   
95.
Background/PurposeThe aim of the study was to evaluate the postoperative quality of life (QoL) of patients who underwent minimally invasive repair of pectus excavatum (MIRPE) with a newly designed bar and bar stabilizers.MethodsWe conducted a prospective randomized study in which patients were operated either with standard perpendicular stabilizers (control group) or with the newly designed oblique stabilizers (intervention group). All patients were evaluated 6 months after the operation with the Pectus Excavatum Evaluation Questionnaire (PEEQ).ResultsThere were 16 patients in the control group and 14 in the intervention group. Mean age was 17 (SD: 3.3, range 14–27) years. There were no demographic differences between groups. Two patients in the control group and one in the intervention group were repaired with two bars instead of one. There was one reoperation in each group. There was a significant difference between the pre- and postoperative scores, in both groups, in the patient body image domain (control group: 9.5 to 3; p < 0.01; intervention group 10 to 3; p < 0.01), as well as in the psychosocial domain (control group: 13.5 to 24, p < 0.01; intervention group: 15 to 24, p < 0.01). With regards to the patients' perception of physical difficulties before and after MIRPE, the difference between pre- and postoperative scores was greater in the intervention group (8 to 12, p < 0.01) than in the control group (10 to 11, p = 0.04). The mean length of stay was 4.5 and 5 days in the intervention group and the control group, respectively.ConclusionOur study showed that patients who underwent MIRPE with the newly designed bars and stabilizers had non-inferior outcomes than patients reported in the literature who underwent MIRPE with standard bars and stabilizers. We found slightly better outcomes in patients in the intervention group compared to the control group, but larger studies will be needed to confirm if those differences are statistically significant.Level of evidenceII  相似文献   
96.
IntroductionLiver transplantation is the standard treatment for end-stage liver disease. Brazil holds the third highest number of liver transplants performed per year, but center maldistribution results in high discrepancies in accessing this treatment. In 2012, an interstate partnership successfully implemented a new liver transplantation program in the middle west of Brazil. Here, we report the results of the first 500 liver transplants performed in this new program and discuss the impacts of a new transplant center in regional transplantation dynamics.MethodsWe reviewed data from the first 500 consecutive deceased donor liver transplants performed in the new program during an 8-year period. We analyzed data on patients’ clinical and demographic profiles, postoperative outcomes, and graft and recipient survival rates. Univariate survival analysis was conducted using log-rank tests to compare the groups.ResultsAlmost half (48%) of the procured organs and 40% of the recipients transplanted in our center were from outside our state. Recipient 30-day mortality was 9%. Overall recipient survival at 1 year and 5 years was 85% and 80%, respectively. Mortality was significantly associated with higher Model for End-Stage Liver Disease (P < .001) but not with the presence of hepatocellular carcinoma (P = .795).DiscussionThe new transplantation program treated patients from different regions of Brazil and became the reference center in liver transplantation for the middle west region. Despite the recent implementation, our outcomes are comparable to experienced centers around the world. This model can inspire the creation of new transplantation programs aiming to democratize access to liver transplantation nationwide.  相似文献   
97.
98.
The net impact of cytomegalovirus (CMV) DNAemia on overall mortality (OM) and nonrelapse mortality (NRM) following allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains a matter of debate. This was a retrospective, multicenter, noninterventional study finally including 749 patients. CMV DNA monitoring was conducted by real-time polymerase chain reaction (PCR) assays. Clinical outcomes of interest were OM and NRM through day 365 after allo-HSCT. The cumulative incidence of CMV DNAemia in this cohort was 52.6%. A total of 306 out of 382 patients with CMV DNAemia received preemptive antiviral therapy (PET). PET use for CMV DNAemia, but not the occurrence of CMV DNAemia, taken as a qualitative variable, was associated with increased OM and NRM in univariate but not in adjusted models. A subcohort analysis including patients monitored by the COBAS Ampliprep/COBAS Taqman CMV Test showed that OM and NRM were comparable in patients in whom either low or high plasma CMV DNA threshold (<500 vs ≥500 IU/mL) was used for PET initiation. In conclusion, CMV DNAemia was not associated with increased OM and NRM in allo-HSCT recipients. The potential impact of PET use on mortality was not proven but merits further research.  相似文献   
99.
100.
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