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   3449篇
  免费   274篇
  国内免费   13篇
耳鼻咽喉   26篇
儿科学   128篇
妇产科学   62篇
基础医学   461篇
口腔科学   98篇
临床医学   268篇
内科学   754篇
皮肤病学   25篇
神经病学   186篇
特种医学   62篇
外国民族医学   1篇
外科学   326篇
综合类   214篇
一般理论   1篇
预防医学   486篇
眼科学   105篇
药学   317篇
中国医学   57篇
肿瘤学   159篇
  2023年   35篇
  2022年   113篇
  2021年   235篇
  2020年   109篇
  2019年   148篇
  2018年   150篇
  2017年   122篇
  2016年   96篇
  2015年   112篇
  2014年   144篇
  2013年   168篇
  2012年   277篇
  2011年   268篇
  2010年   119篇
  2009年   82篇
  2008年   183篇
  2007年   165篇
  2006年   158篇
  2005年   145篇
  2004年   116篇
  2003年   103篇
  2002年   93篇
  2001年   74篇
  2000年   61篇
  1999年   56篇
  1998年   24篇
  1997年   18篇
  1996年   14篇
  1995年   18篇
  1994年   16篇
  1993年   11篇
  1992年   29篇
  1991年   27篇
  1990年   25篇
  1989年   20篇
  1988年   21篇
  1987年   17篇
  1986年   12篇
  1985年   16篇
  1984年   13篇
  1983年   13篇
  1980年   10篇
  1978年   7篇
  1976年   7篇
  1975年   11篇
  1974年   7篇
  1973年   6篇
  1972年   7篇
  1971年   9篇
  1970年   8篇
排序方式: 共有3736条查询结果,搜索用时 343 毫秒
131.

Background

Arsenic exposure and micronutrient deficiencies may alter immune reactivity to influenza vaccination in pregnant women, transplacental transfer of maternal antibodies to the foetus, and maternal and infant acute morbidity.

Objectives

The Pregnancy, Arsenic, and Immune Response (PAIR) Study was designed to assess whether arsenic exposure and micronutrient deficiencies alter maternal and newborn immunity and acute morbidity following maternal seasonal influenza vaccination during pregnancy.

Population

The PAIR Study recruited pregnant women across a large rural study area in Gaibandha District, northern Bangladesh, 2018–2019.

Design

Prospective, longitudinal pregnancy and birth cohort.

Methods

We conducted home visits to enrol pregnant women in the late first or early second trimester (11–17 weeks of gestational age). Women received a quadrivalent seasonal inactivated influenza vaccine at enrolment. Follow-up included up to 13 visits between enrolment and 3 months postpartum. Arsenic was measured in drinking water and maternal urine. Micronutrient deficiencies were assessed using plasma biomarkers. Vaccine-specific antibody titres were measured in maternal and infant serum. Weekly telephone surveillance ascertained acute morbidity symptoms in women and infants.

Preliminary Results

We enrolled 784 pregnant women between October 2018 and March 2019. Of 784 women who enrolled, 736 (93.9%) delivered live births and 551 (70.3%) completed follow-up visits to 3 months postpartum. Arsenic was detected (≥0.02 μg/L) in 99.7% of water specimens collected from participants at enrolment. The medians (interquartile ranges) of water and urinary arsenic at enrolment were 5.1 (0.5, 25.1) μg/L and 33.1 (19.6, 56.5) μg/L, respectively. Water and urinary arsenic were strongly correlated (Spearman's ⍴ = 0.72) among women with water arsenic ≥ median but weakly correlated (⍴ = 0.17) among women with water arsenic < median.

Conclusions

The PAIR Study is well positioned to examine the effects of low-moderate arsenic exposure and micronutrient deficiencies on immune outcomes in women and infants. Registration : NCT03930017.  相似文献   
132.

Large treatment deficits in child and adolescent mental health (CAMH) care exist in low and middle income countries (LMICs). This study reviewed CAMH training programs for non-specialist health professionals (NSHPs) in LMICs. Multiple databases were searched for peer-reviewed articles describing programs from 2005 to 2018. Educational source materials, trainee evaluation methods, and perspectives on teaching methods, course content and scheduling were studied. Six programs were identified. NSHPs were most appreciative of training which included case-based discussions, role plays and clinical demonstrations that were relevant to local contexts. A need for less intense and more flexible timetables to enable reflection was identified. WHO’s mental health gap action program intervention guide (mhGAP-IG) and international association of child and adolescent psychiatrists and allied professionals resources should be used; they are free, easily accessible, and developed with extensive international contributions. Additionally, mhGAP-IG assessment tool encourages mutual learning, thereby iteratively enhancing training programs.

  相似文献   
133.

Introduction and hypothesis

The prevalence of symptomatic pelvic organ prolapse (POP), diagnosed by a pre-tested structured questionnaire, is unknown in Bangladesh. We investigated the prevalence of, and risk factors for, symptomatic POP in women in rural Bangladesh, recruited from the community.

Methods

A cross-sectional survey of 787 women aged over 15 years was conducted in four villages in one district in rural Bangladesh. The prevalence of symptomatic POP and the risk factors associated with the condition was investigated, using Chi-squared and multivariate logistic regression.

Results

The prevalence of symptomatic POP was 15.6 %. The mean age of participants was 40.1 (±9.0) years. Women aged 35–44 years (odds ratio [OR] 1.96, 95 % confidence interval [CI] 1.03–3.73) and ≥45 years (OR 2.95, 95 % CI 1.62–5.38) were more likely to have POP compared with women aged ≤35 years. Having POP was positively associated with women having ≥5 children (OR 4.34, 95 % CI 1.39–13.58), having chronic obstructive pulmonary disease (COPD; OR 2.07, 95 % CI 1.02–4.21), and women having constipation (OR 3.54, 95 % CI 1.87–6.72). Women whose husband had >5 years of schooling were less likely to have POP (OR 0.37, 95 % CI 0.19–0.73) compared with women whose husband had no schooling.

Conclusions

Symptomatic POP affects a substantial proportion of women in rural Bangladesh and increases with age. Parity, COPD, constipation and husband’s education are associated with POP, all of which have the potential to be modified. Thus, interventions targeting these risk factors to prevent the condition are urgently needed in Bangladesh.
  相似文献   
134.
135.
Hemifacial hypertrophy (HFH) is rare and characterized by unilateral enlargement of the head and teeth. Hemifacial hypertrophy is classified as true HFH (THFH) with unilateral enlargement of the viscerocranium, and partial HFH (PHFH) in which not all structures are enlarged. We present a case of THFH and compare and contrast it with a case of PHFH. Hemifacial hypertrophy may cover a wide spectrum of defects or may involve only muscle or bone. Myohyperplasia, reported previously as a separate syndrome, may actually represent a forme fruste of PHFH or THFH. The PHFH patient lead a healthy, normal life without significant psychosocial problems and was reluctant to accept his deformity. Contrastingly, the THFH patient had significant social stigma and compromised health together with major aesthetic morbidity. Treatment planning in THFH is arduous and involves multiple modalities. Therefore, it is imperative to differentiate THFH and PHFH for better understanding and management of the condition.  相似文献   
136.
Zygomycosis or mucormycosis is an increasingly frequent life-threatening infection caused by opportunistic fungal organisms of the class Zygomycetes. The pathognomonic feature is the presence of invasive aseptate mycelia that are larger than other filamentous fungi with the hyphae exhibiting right angle and haphazard branching. Usually classified as rhinocerebral, disseminated, and cutaneous types, this classification serves as important predictor of pathogenesis and outcome. These occur mostly in immunosuppressed patients including individuals with diabetes (43% exhibit the rhino-cerebral form) and patients with organ transplants and hematologic malignancies. Without early aggressive treatment, the disease follows a dismal and fatal course. The prognosis has not shown any appreciable change in the past 40 years with a stagnant mortality rate of 44%. We present 2 cases of rhinocerebral zygomycosis (RCZ), in a 58-year-old male and a 63-year-old female; both were poorly controlled diabetic patients with maxillary lesions suggestive of osteomyelitis. The patients were leading a near normal life with minimal discomfort or signs and symptoms of underlying mycosis. Most of the health care professionals treating these patients often overlooked the disease or recommended inadequate therapy. Despite long delays and inadequate initial therapy these patients survived with little outward morbidity. The prognosis for this condition may therefore be considered less dire than previously thought.  相似文献   
137.
Dual localization of SLN in breast cancer patients using isotope & dye is the best‐approved modality with limitations such as high cost of radioactive materials, complex logistic preparations & scheduling issues, especially in developing countries. We investigated the feasibility & accuracy of a novel technique for SLN localization using silver wire insertion or liquid charcoal injection guided by CT lymphography. 120 patients with clinically node‐negative breast cancer were enrolled. In the test group, SLN was localized using preoperative CTLG guided injection of liquid charcoal or by placing a 3 cm silver wire. In addition, intraoperative SLN mapping was performed using methylene blue dye followed by searching for the SLN localized by both methods. In the control group, SLN was localized by the blue dye only. Feasibility, accuracy, detection rates, and number of SLNs retrieved were reported as well as matching between the LN detected with the CTLG and that detected with the dye technique. SLN could be detected in 59 out of 60 patients (98.3%) in the test group and in 54 out of 60 patients (90%) in the control group (P = .057). In self‐controlled analysis of the test group comparing CTLG only to dye only was significant (P = .050). Comparing charcoal to silver wire in detection was statistically insignificant (P = .5). This novel method can offer advantages which are as follows: being more accurate than the dye alone, saving operative time, abandoning complex logistic preparations for the radioisotope, and solving the problem of timing.  相似文献   
138.

Purpose

Compared to low-grade disease, high-grade prostate cancers exhibit a higher rate of disease progression. As a result, there has been a trend to treat high-risk disease with methods other than surgery. The purpose of this study is to evaluate the long-term survival following radical prostatectomy (RRP) for non-metastatic Gleason 8–10 prostate adenocarcinoma (CaP).

Methods

All patients 75 years or less with Gleason 8–10 CaP that underwent RRP were identified from the SEER 18 database. Patients with metastatic disease, those who underwent other modalities of treatment, or with more than one primary cancer, were excluded. Data were analyzed for demographics, stage at presentation, treatment modality, and overall survival and cancer-specific survival.

Results

A total of 30,379 men met inclusion criteria. Mean age was 62.5 years and 82.5 % of patients were white. A total of 52.8 % of patients had T2 disease, and 73.1 % had node-negative disease, 80.2 % of patients underwent pelvic lymph node dissection, and 12.9 % underwent adjuvant radiation therapy. Overall survival for the entire cohort was 92.8, 78.6, 59.5, 38.6, and 20.0 % for 5, 10, 15, 20, and 25 years, respectively. Cancer-specific survival was 96.4, 89.5, 82.0, 72.9, and 68.8 % for 5, 10, 15, 20, and 25 years, respectively.

Conclusions

Although historically underutilized in patients with poorly differentiated disease, radical prostatectomy provides excellent long-term survival and should be offered to healthy patients.  相似文献   
139.
140.
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