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   33937篇
  免费   2548篇
  国内免费   186篇
耳鼻咽喉   446篇
儿科学   830篇
妇产科学   572篇
基础医学   4198篇
口腔科学   703篇
临床医学   3206篇
内科学   7179篇
皮肤病学   750篇
神经病学   2964篇
特种医学   1244篇
外国民族医学   2篇
外科学   5318篇
综合类   592篇
一般理论   29篇
预防医学   2449篇
眼科学   853篇
药学   2467篇
中国医学   172篇
肿瘤学   2697篇
  2023年   168篇
  2021年   732篇
  2020年   413篇
  2019年   683篇
  2018年   761篇
  2017年   580篇
  2016年   715篇
  2015年   915篇
  2014年   1160篇
  2013年   1520篇
  2012年   2300篇
  2011年   2185篇
  2010年   1300篇
  2009年   1117篇
  2008年   1852篇
  2007年   1916篇
  2006年   1887篇
  2005年   1863篇
  2004年   1702篇
  2003年   1567篇
  2002年   1451篇
  2001年   636篇
  2000年   549篇
  1999年   514篇
  1998年   317篇
  1997年   272篇
  1996年   253篇
  1995年   258篇
  1994年   221篇
  1993年   204篇
  1992年   340篇
  1991年   280篇
  1990年   307篇
  1989年   240篇
  1988年   265篇
  1987年   248篇
  1986年   231篇
  1985年   225篇
  1984年   226篇
  1983年   225篇
  1982年   224篇
  1981年   213篇
  1980年   223篇
  1979年   218篇
  1978年   171篇
  1977年   138篇
  1976年   149篇
  1975年   127篇
  1974年   159篇
  1973年   137篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
Child undernutrition is responsible for 45% of all under-five deaths in low- and middle-income countries (LMICs) and numerous morbidities. Although progress has been made, high levels of child undernutrition persist in Zambia. Existing studies have explored primary caretakers' (PCs) explanatory models of child undernutrition in LMICs, without comparison with those of health care providers (HCPs). This paper examines and compares the perceived causes of child undernutrition among PCs and HCPs in Zambia. We conducted a qualitative study, using semistructured one-to-one and group interviews, with 38 PCs and 10 HCPs to explore their perceptions of child undernutrition and its perceived causes in Lusaka district, Zambia. Interview data were analysed with thematic analysis. Our findings indicate that PCs and HCPs in Lusaka district have divergent explanatory models of child undernutrition and perceive parental agency differently. In divergently framing how they conceptualise undernutrition and who is able to prevent it, these models underpin different attributions of causality and different opportunities for intervention. PCs highlighted factors such as child food preferences, child health, and household finances. Contrarily, HCPs stressed factors such as ‘improper feeding’, only highlighting factors such as wider economic conditions when these impacted specifically on health care services. One factor, identified by both groups, was ‘inadequate mothering’. To accelerate the reduction of child undernutrition, interventions must address divergences between PCs and HCPs' explanatory models. Additionally, attention needs to be paid to how wider socio-economic and cultural contexts not only impact childhood undernutrition but shape attributions of causality.  相似文献   
4.
In this review we summarize the impact of the various modalities of breast cancer therapy coupled with intrinsic patient factors on incidence of subsequent treatment-induced myelodysplasia and acute myelogenous leukemia (t-MDS/AML). It is clear that risk is increased for patients treated with radiation and chemotherapy at younger ages. Radiation is associated with modest risk, whereas chemotherapy, particularly the combination of an alkylating agent and an anthracycline, carries higher risk and radiation and chemotherapy combined increase the risk markedly. Recently, treatment with granulocyte colony-stimulating factor (G-CSF), but not pegylated G-CSF, has been identified as a factor associated with increased t-MDS/AML risk. Two newly identified associations may link homologous DNA repair gene deficiency and poly (ADP-ribose) polymerase inhibitor treatment to increased t-MDS/AML risk. When predisposing factors, such as young age, are combined with an increasing number of potentially leukemogenic treatments that may not confer large risk singly, the risk of t-MDS/AML appears to increase. Patient and treatment factors combine to form a biological cascade that can trigger a myelodysplastic event. Patients with breast cancer are often exposed to many of these risk factors in the course of their treatment, and triple-negative patients, who are often younger and/or BRCA positive, are often exposed to all of them. It is important going forward to identify effective therapies without these adverse associated effects and choose existing therapies that minimize the risk of t-MDS/AML without sacrificing therapeutic gain.

Implications for Practice

Breast cancer is far more curable than in the past but requires multimodality treatment. Great care must be taken to use the least leukemogenic treatment programs that do not sacrifice efficacy. Elimination of radiation and anthracycline/alkylating agent regimens will be helpful where possible, particularly in younger patients and possibly those with homologous repair deficiency (HRD). Use of colony-stimulating factors should be limited to those who truly require them for safe chemotherapy administration. Further study of a possible leukemogenic association with HRD and the various forms of colony-stimulating factors is badly needed.
  相似文献   
5.
Background: Weight loss is frequently observed in pancreatic cancer patients. We aimed to study the prognostic impacts of weight loss early during chemotherapy.

Methods: A total of 72 patients of Chinese ethnicity with unresectable pancreatic cancer who underwent chemotherapy were reviewed. Critical weight loss (CWL) was defined as weight loss ≥ 5% within one month after treatment. The prognostic impact of weight loss and CWL were analyzed.

Results: 47 patients (65.3%) had weight loss after one month of treatment, with 14 (19.4%) suffering from CWL. Baseline characteristics were similar between patients with and without CWL. The median OS and Time-to-treatment-failure (TTF) of patients with CWL were shorter than those without CWL (OS: 4.8?months [CWL] versus [vs.] OS 7.1?months [No CWL]; TTF 1.6?months [CWL] vs. 3.2?months [No CWL]; both P?<?0.01). CWL was an independent adverse prognosticator for OS (Hazard Ratio [HR]?=?2.50; P?=?0.01) and TTF (HR = 2.71; P?<?0.01). Other independent prognosticators for OS were serum albumin <35?mg/dl and CA19-9?≥?1000?IU/ml, while CWL was the only independent prognosticator for TTF (HR 2.71 [95% CI 1.33–5.52]; P?<?0.01).

Conclusions: Development of CWL in early course of chemotherapy was associated with worse prognosis in Chinese patients with unresectable pancreatic cancers.  相似文献   

6.
Journal of Neuro-Oncology - Primary central nervous system lymphoma (PCNSL) is a subtype of non-Hodgkin’s lymphoma that involves the brain, spinal cord, or leptomeninges, without evidence of...  相似文献   
7.
Fordyce spots are ectopic sebaceous glands which typically present as asymptomatic, multiple whitish, or yellowish 1–3‐mm sized papules on the lips. Several therapeutic approaches have been proposed such as laser, electrical or chemical ablation, and micropunch excision. However, these modalities pose the risk of scarring from inevitable surface damage. In this report, we present a case of Fordyce spots which was successfully treated with intralesional electrocoagulation using a proximally insulated microneedle and monopolar radiofrequency device, resulting in marked cosmetic improvements without surface damage.  相似文献   
8.
9.
ObjectiveMost guidelines advise no adjuvant radiotherapy in vulvar squamous cell carcinoma and a single occult intracapsular lymph node metastasis. However, several recent studies have questioned the validity of this recommendation. The aim of this study was to analyze the groin recurrence rate in patients with a single intracapsular positive lymph node treated without adjuvant radiotherapy.MethodsPatients with a single clinically occult intracapsular lymph node metastasis, treated without adjuvant radiotherapy, formed the basis for this study. Groin recurrences, and the risk of death, were analyzed in relation to the size of the metastasis in the lymph node and the lymph node ratio. Data were analyzed using SPSS, version 26.0 for Windows.ResultsAfter a median follow-up of 64 months, one of 96 patients (1%) was diagnosed with an isolated groin recurrence and another two (2.1%) were diagnosed with a combination of a local and a groin recurrence. The only isolated groin recurrence occurred in a contralateral lymph node negative groin. Size of the metastasis and lymph node ratio had no impact on the groin recurrence risk, nor on survival. The 5-year actuarial disease-specific and overall survivals were 79% and 62.5% respectively. The 5-year actuarial groin recurrence-free survival was 97%.ConclusionBecause of the low risk of groin recurrence and the excellent groin recurrence-free survival, we recommend that adjuvant radiotherapy to the groin in patients with vulvar squamous cell carcinoma and a single occult intracapsular lymph node metastasis can be safely omitted to prevent unnecessary toxicity and morbidity.  相似文献   
10.
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