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   4214篇
  免费   308篇
  国内免费   56篇
耳鼻咽喉   26篇
儿科学   121篇
妇产科学   89篇
基础医学   618篇
口腔科学   242篇
临床医学   360篇
内科学   1034篇
皮肤病学   46篇
神经病学   332篇
特种医学   221篇
外国民族医学   1篇
外科学   429篇
综合类   43篇
一般理论   24篇
预防医学   438篇
眼科学   48篇
药学   165篇
中国医学   5篇
肿瘤学   336篇
  2023年   19篇
  2022年   30篇
  2021年   59篇
  2020年   47篇
  2019年   92篇
  2018年   98篇
  2017年   79篇
  2016年   85篇
  2015年   92篇
  2014年   117篇
  2013年   138篇
  2012年   129篇
  2011年   139篇
  2010年   124篇
  2009年   133篇
  2008年   193篇
  2007年   183篇
  2006年   166篇
  2005年   147篇
  2004年   144篇
  2003年   134篇
  2002年   160篇
  2001年   151篇
  2000年   127篇
  1999年   141篇
  1998年   96篇
  1997年   87篇
  1996年   95篇
  1995年   64篇
  1994年   69篇
  1993年   43篇
  1992年   121篇
  1991年   111篇
  1990年   96篇
  1989年   117篇
  1988年   96篇
  1987年   79篇
  1986年   77篇
  1985年   68篇
  1984年   64篇
  1983年   23篇
  1982年   40篇
  1981年   21篇
  1980年   34篇
  1979年   29篇
  1978年   21篇
  1977年   20篇
  1976年   18篇
  1975年   18篇
  1968年   16篇
排序方式: 共有4578条查询结果,搜索用时 31 毫秒
991.
Medicine, Health Care and Philosophy -  相似文献   
992.
Medicine, Health Care and Philosophy -  相似文献   
993.

Introduction

In studies of colorectal cancer, the elderly have been frequently underrepresented because comorbid conditions and functional status often lead to study exclusion. For elderly patients with an indication for neoadjuvant chemoradiotherapy (nCRT), physicians usually decide using clinical factors whether nCRT should be offered. The aim of the present retrospective study was to assess the tolerability of nCRT with capecitabine and the surgical outcomes in patients aged ≥ 70 years with locally advanced rectal cancer.

Patients and Methods

Data from 1372 rectal cancer patients diagnosed from 2002 to 2012 at 4 Dutch hospitals were used. Patients aged ≥ 70 years were included if they had received nCRT, and their data were analyzed for treatment deviations, postoperative complications, mortality, disease-free survival (DFS), and overall survival (OS). The data were stratified into 3 age groups (ie, 70-74, 75-79, and ≥ 80 years).

Results

We identified 447 patients aged ≥ 70 years. Of these patients, 42 had received nCRT, and 37 (88%) had completed nCRT. Radiation dermatitis, fatigue, and diarrhea were reported in 62%, 57%, and 43% of the 42 patients, respectively. Of the 42 patients, 40 (95%) underwent surgery, 1 patient refused resection, and 1 patient died during nCRT of severe mucositis due to dihydropyrimidine dehydrogenase deficiency. The postoperative complication rate was 30%, and the 30-day mortality rate was 0%. A pathologic complete response was found in 7.5%. The 2- and 5-year DFS and OS rates were 58.5% and 40.7% and 81.0% and 58.2%, respectively.

Conclusion

The results of the present multicenter study have shown that if selected on clinical factors, nCRT with capecitabine is safe and well tolerated in elderly patients. No negative effect on surgical outcome was measured, and the beneficial effect (pathologic complete response, DFS, and OS) seemed comparable to that for younger age groups. We believe that elderly patients should not be excluded from nCRT on the basis of age only.  相似文献   
994.
Accidental injury is a principal public health issue with important individual, societal and economic consequences. Crude figures show that 2.7 million deaths from injury and poisoning are reported worldwide. In developing and industrialized countries 10–30% of all hospital admissions are due to accidental injuries. In particular, children and adolescents are at risk. In all industrialized countries accidental injuries are the major cause of death and morbidity among children above the age of one. In the domestic safety area much effort has to be invested in improving the safety of the environment and products. In the European region, collaboration among authorities in the framework of the European Community (EC) has been shown to be productive in the area of safety. Although trade interest is predominant in the EC objectives, the need to harmonize national regulations and standards towards common European standards has appeared to be an important vehicle for establishing standards at an optimum level of safety. It has also fostered some collaboration in data collection and analysis and in implementing prevention measures. An even stronger international collaboration is needed for ensuring that appropriate priorities are being set and prevention measures are effectively being implemented.  相似文献   
995.

Background

The LIRIK, an instrument for the assessment of child safety and risk, is designed to improve assessments by guiding professionals through a structured evaluation of relevant signs, risk factors, and protective factors.

Objective

We aimed to assess the interrater agreement and the predictive validity of professionals’ judgments made with the LIRIK in comparison to unstructured judgments.

Method

In study 1, professionals made safety and risk judgments for 12 vignettes with the LIRIK (group 1, n = 36) or without an instrument (group 2, n = 43). In study 2, we compared professionals’ safety and risk judgments for 370 children made with the LIRIK (group 1, n = 278) or with no instrument (group 2, n = 92), with outcomes indicating actual unsafety in files 6 months later.

Results

In study 1, agreement about safety and risks was poor to moderate in both groups. Differences between groups were small and inconsistent. In study 2, the predictive validity of judgments was weak to moderate in both groups. In neither group had unsafe outcomes increased consistently when unsafety or risks were assessed as higher.

Conclusions

Judgments made with the LIRIK were not more reliable or valid than unstructured professional judgments. These findings raise important questions about the value of risk assessment instruments and about how professional safety and risk judgments can be improved.
  相似文献   
996.
Lynch syndrome (LS) is the most common inherited cancer syndrome. It is inherited via a monoallelic germline variant in one of the DNA mismatch repair (MMR) genes. LS carriers have a broad 30% to 80% risk of developing various malignancies, and more precise, individual risk estimations would be of high clinical value, allowing tailored cancer prevention and surveillance. Due to MMR deficiency, LS cancers are characterized by the accumulation of frameshift mutations leading to highly immunogenic frameshift peptides (FSPs). Thus, immune surveillance is proposed to inhibit the outgrowth of MMR-deficient cell clones. Recent studies have shown that immunoediting during the evolution of MMR-deficient cancers leads to a counter-selection of highly immunogenic antigens. The immunogenicity of FSPs is dependent on the antigen presentation. One crucial factor determining antigen presentation is the HLA genotype. Hence, a LS carrier's HLA genotype plays an important role in the presentation of FSP antigens to the immune system, and may influence the likelihood of progression from precancerous lesions to cancer. To address the challenge of clarifying this possibility including diverse populations with different HLA types, we have established the INDICATE initiative (Individual cancer risk by HLA type, http://indicate-lynch.org/ ), an international network aiming at a systematic evaluation of the HLA genotype as a possible cancer risk modifier in LS. Here we summarize the current knowledge on the role of HLA type in cancer risk and outline future research directions to delineate possible association in the scenario of LS with genetically defined risk population and highly immunogenic tumors.  相似文献   
997.
Eleven patients with suspected adult respiratory distress syndrome (ARDS) and five control patients were studied using a computerized gamma imaging and analysis technique and 99mTc-labeled human serum albumin. The heart and right lung were imaged, lung:heart ratio was plotted vs. time, and a linear regression was fitted to the data points displayed. The slope of this fit was termed the "slope index." An index value of 2 standard deviations greater than the control mean was considered positive. Radiographs from the six positive studies revealed typical diffuse air-space disease. Radiographs from two of the five negative studies demonstrated air-space consolidation. Both of these patients had elevated pulmonary capillary wedge pressure, cardiomegaly, and clinical course consistent with cardiogenic pulmonary edema. These preliminary data demonstrated a good correlation between positive slope index and clinical ARDS.  相似文献   
998.
999.
1000.
All consecutive cases entering the mental health services cooperating with the cumulative psychiatric case register of Mannheim between 1-31 July 1976 were followed up until the end of June 1978 and compared with the consecutive cases entering the mental health services cooperating with the psychiatric case register of Groningen between 1 January and 1 May 1979. Patterns of in-, day- and outpatient care delivered to these 2 cohorts of patients, who were greater than or equal to 15 years of age, and who had not been in contact with one of the services for at least 6 months prior to entry, were compared by diagnostic category. The most common episode of care was the relatively brief outpatient one. Mixed types of care and chronic cases were more common among patients with a psychosis or an addiction than in other diagnostic categories. Between 6 and 24 months after first contact 76% of the patients in Mannheim and 43% of the patients in Groningen had no more contacts. Between 18 and 24 months after the first contact the percentages had increased to 90 and 72% (respectively). In Groningen a higher percentage of patients received outpatient care only. Although a larger percentage of patients in Mannheim received inpatient care, the accumulation of "new chronic" patients was larger in Groningen, as a result of a greater length of stay in Groningen.  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