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   6552篇
  免费   468篇
  国内免费   28篇
耳鼻咽喉   43篇
儿科学   234篇
妇产科学   109篇
基础医学   758篇
口腔科学   206篇
临床医学   516篇
内科学   1555篇
皮肤病学   71篇
神经病学   241篇
特种医学   285篇
外国民族医学   1篇
外科学   641篇
综合类   432篇
一般理论   2篇
预防医学   794篇
眼科学   143篇
药学   573篇
中国医学   89篇
肿瘤学   355篇
  2023年   45篇
  2022年   135篇
  2021年   269篇
  2020年   139篇
  2019年   188篇
  2018年   176篇
  2017年   155篇
  2016年   165篇
  2015年   180篇
  2014年   237篇
  2013年   318篇
  2012年   541篇
  2011年   470篇
  2010年   281篇
  2009年   241篇
  2008年   354篇
  2007年   357篇
  2006年   310篇
  2005年   305篇
  2004年   244篇
  2003年   229篇
  2002年   179篇
  2001年   145篇
  2000年   126篇
  1999年   125篇
  1998年   101篇
  1997年   84篇
  1996年   72篇
  1995年   52篇
  1994年   41篇
  1993年   45篇
  1992年   68篇
  1991年   56篇
  1990年   43篇
  1989年   71篇
  1988年   55篇
  1987年   44篇
  1986年   51篇
  1985年   56篇
  1984年   33篇
  1983年   29篇
  1982年   24篇
  1981年   20篇
  1980年   21篇
  1979年   23篇
  1978年   17篇
  1977年   17篇
  1976年   13篇
  1975年   18篇
  1973年   16篇
排序方式: 共有7048条查询结果,搜索用时 31 毫秒
71.
72.
BACKGROUND: Although the recent decline in child mortality in Bangladesh is remarkable, death from causes other than infectious diseases and malnutrition remains an important component of child mortality. Death from drowning of children can be expected to be a problem in Bangladesh given the geographical features of the country. OBJECTIVE: The objectives of this study are to determine the trend, pattern, and correlates of drowning deaths. METHODS: Data are presented on deaths of children (1-4 years) due to drowning derived from a longitudinal, population-based surveillance system in operation in a rural area of Bangladesh in 1983-1995. Moreover, a case-control study was carried out to identify the risk factors associated with drowning. RESULTS: Deaths due to drowning ranged from about 10% to 25% of child deaths during 1983-1995. The absolute risk of dying from drowning remained almost the same over the study period but the proportion of drownings to all causes of death has increased. Drowning is especially prevalent in the second year of life. Age of the mother and parity have a significant impact on drowning. The risk of dying from drowning increases with the age of mother and much more sharply with the number of living children in the family. Two socioeconomic variables did not have an influence on the risk of drowning. CONCLUSIONS: A substantial proportion of child deaths could be averted if parents and other close relatives paid more attention to the safety of children. The Child Health Programme of the Ministry of Health and Family Welfare of Bangladesh should develop health education programmes for villagers alerting them to the dangers of drowning and measures to prevent it.  相似文献   
73.
An extensive iodine deficiency disorders survery was conducted in Bangladesh in 1993 to assess the latest iodine nutriture status of the country. The clinical variables of the survey were goitre and cretinism, and the biochemical variable was urinary iodine. The “EPI-30 cluster” sampling methodology was followed for selecting the survey sites. In each survey site, the study population consisted of boys and girls, aged 5–11 years, and men and women, aged 15–44 years, in about equal populations. the total number of survey sites was 78 and the total number of respondents was 30 072. The total number of urine samples was 4512 (15% sub-sample). The current total goitre rate (grade 1+grade 2) in Bangladesh is 47.1% (hilly, 44.4%; flood-prone, 50.7%; and plains, 45.6%). The prevalence of cretinism in the country is 0.5% (hilly, 0.8%; flood-prone, 0.5%; and plains, 0.3%). Nearly 69% of Bangladeshi population have biochemical iodine deficiency (urinary iodine excretion [UIE]<10 mg/dl) (hilly, 84.4; flood-prone, 67.1%; and plains 60.4%). Women and children are more affected than men, in terms of both goitre prevalence and UIE. The widespread severe iodine deficiency in all ecological zones indicates that the country as a whole is an iodine-deficient region. Important recommendations of global interest are made from the experience of the survey. An erratum to this article is available at .  相似文献   
74.
  • 1 It was first shown several years ago that the rostral part of the ventrolateral medulla (VLM) contains a high density of receptor binding sites for angiotensin II (AngII). In the present paper we briefly review recent studies aimed at determining the actions of both exogenous and endogenous angiotensin peptides in the rostral VLM, as well as their specific sites of action.
  • 2 The results of these studies have shown that angiotensin peptides can excite pressor and sympathoexcitatory neurons in the rostral VLM, but do not appear to affect non-cardiovascular neurons in this region.
  • 3 It is known that pressor neurons in the rostral VLM include both catecholamine and non-catecholamine neurons. There is evidence that, at least in conscious rabbits, both of these types of neurons are activated by AngII. The specific endogenous angiotensin peptide or peptides that affect pressor neurons in the rostral VLM have not yet been definitively identified.
  • 4 It is also possible that different angiotensin peptides may have different effects on pressor neurons in the rostral VLM, mediated by different receptors. Further studies will be needed to define these different functions as well as the specific receptors and cellular mechanisms that subserve them.
  相似文献   
75.
Few attempts have been made to determine the risk factors for diabetic retinopathy which is a major cause of visual impairment and blindness. One hundred and forty patients of diabetes mellitus were studied to determine the prevalence and types of retinopathy, and its relation to various risk factors. Nearly half (48.6%) of the patients suffered from retinopathy. The significant associated risk factors were long duration of diabetes, proteinuria and elevated serum creatinine level. However, there was no significant association between the prevalence of retinopathy and high levels of serum cholesterol, C-peptide levels, associated hypertension, and glycaemic control of diabetes mellitus. An effective screening programme for detection of retinopathy in the patients of diabetes as a regular practice is encouraged.  相似文献   
76.
In 6 hemodialysis patients, enriching the "base concentrate" of a bicarbonate-containing dialysate-generating system with phosphorus succeeded in raising plasma phosphorus levels.  相似文献   
77.
AIMS: To analyse retrospectively all referrals to the assessment unit during a seven year period, to determine their sources and destination. METHODS: All referrals over the seven year period were analysed. Parental satisfaction was determined using a questionnaire in some of the patients. The disease pattern and the investigations performed were determined. The community nurses' working hours and type of work done were analysed. RESULTS AND CONCLUSIONS: A total of 43 496 children were seen in the unit. Over 65% of the patients were referred by the general practitioners; 13 517 (34.2%) of those referred to the unit were discharged directly from the unit. Respiratory disorders and gastrointestinal problems were commonly seen. The children discharged from the unit did not have significantly more tests done on them. Most of the parents whose children were discharged from the unit were happy to be managed at home. The community nurses attended many children who needed intravenous therapy and advice on fluid rehydration. Community nurses reduce admission to the wards by working with other members in the assessment unit. This in turn provides a single point of entry and bridges the gap between primary and secondary care. We suggest recommendations on setting up such a unit.  相似文献   
78.
Infantile Systemic Hyalinosis is a rare autosomal recessive entity, characterised by deposition of hyaline material in skin and bone, often complicated by visceral involvement. The characteristic features are marked delay in motor milestones attributed to severe progressive flexion contractures of proximal and distal joints, and skin and mucosal hypertrophy and thickening, followed by failure to thrive. Pain secondary to osteolytic lesions is also a predominant feature. We report a patient with Infantile Systemic Hyalinosis, confirmed by the clinical findings, who also displayed clear evidence of proximal muscle weakness. Muscle biopsy revealed myopathic changes, which have not been reported previously. We suggest that skeletal muscle is involved in Infantile Systemic Hyalinosis and contributes to the characteristic poor outcome of these patients.  相似文献   
79.
80.
Evaluation of osteopontin as biomarker for pancreatic adenocarcinoma.   总被引:19,自引:0,他引:19  
OBJECTIVES: Pancreatic adenocarcinoma is a deadly disease with an overall 5-year patient survival of less than 5%. This dismal prognosis of pancreatic cancer is largely due to the advanced stage of the disease at presentation. If pancreatic cancer could be diagnosed more readily and accurately using serum markers, patient survival could theoretically be improved by enabling more patients to avail of surgical resection. One candidate tumor marker recently identified by global gene expression analysis of pancreatic cancer is the secreted glycophosphoprotein osteopontin (OPN). In this study, we evaluate OPN as a serum marker of pancreatic adenocarcinoma. METHODS: In situ hybridization for OPN was performed on a pancreatic adenocarcinoma tissue microarray. Serum OPN levels were determined in preoperative sera from 50 patients with pancreatic cancer and 22 healthy control individuals by competitive ELISA. RESULTS: In situ hybridization for OPN performed on a tissue microarray revealed strong OPN mRNA signal in tumor-infiltrating macrophages in 8 of 14 pancreatic adenocarcinomas. In contrast, OPN expression was not seen in the pancreatic cancer cells themselves, nor was it seen in normal pancreatic tissue or in the macrophages distant from the infiltrating cancer. Serum OPN levels, as measured by ELISA, were elevated in the sera of 50 patients with resectable pancreatic adenocarcinoma compared to 22 healthy control individuals (mean +/- SD for OPN was 482 +/- 170 ng/ml and 204 +/- 65 ng/ml, respectively; P < 0.001). Using a cutoff level of 2 SD above the mean for healthy individuals, elevated OPN had sensitivity of 80% and specificity of 97% for pancreatic cancer. In contrast, only 62% of these patients with resectable pancreatic cancer had elevated CA19-9. CONCLUSIONS: Serum OPN may have utility as a diagnostic marker in patients with pancreatic cancer.  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