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   377篇
  免费   74篇
  国内免费   1篇
儿科学   7篇
妇产科学   8篇
基础医学   46篇
临床医学   32篇
内科学   41篇
皮肤病学   11篇
神经病学   22篇
特种医学   6篇
外科学   58篇
综合类   12篇
预防医学   44篇
眼科学   1篇
药学   146篇
中国医学   1篇
肿瘤学   17篇
  2021年   5篇
  2019年   3篇
  2018年   4篇
  2017年   3篇
  2016年   7篇
  2015年   7篇
  2014年   9篇
  2013年   19篇
  2012年   21篇
  2011年   5篇
  2010年   11篇
  2009年   7篇
  2008年   17篇
  2007年   20篇
  2006年   15篇
  2005年   16篇
  2004年   15篇
  2003年   18篇
  2002年   18篇
  2001年   25篇
  2000年   20篇
  1999年   11篇
  1998年   3篇
  1997年   3篇
  1996年   9篇
  1995年   4篇
  1993年   4篇
  1992年   17篇
  1991年   11篇
  1990年   10篇
  1989年   6篇
  1988年   4篇
  1987年   7篇
  1986年   8篇
  1985年   7篇
  1983年   4篇
  1982年   6篇
  1979年   7篇
  1978年   3篇
  1976年   2篇
  1974年   4篇
  1973年   5篇
  1972年   8篇
  1971年   4篇
  1969年   6篇
  1968年   9篇
  1967年   4篇
  1966年   3篇
  1964年   2篇
  1949年   2篇
排序方式: 共有452条查询结果,搜索用时 0 毫秒
1.
In 38 miscarrying women and 38 pair-matched controls, all studied retrospectively, the mean pair-difference in MCV is + 1.2 fl, P less than 0.05 (one-tailed). As ethanol elevates MCV, this might weakly support the suggested role of ethanol in some miscarriages, although folate/B12 deficiencies cannot be excluded. The paper demonstrates only the feasibility of a first step in defining the possible role of ethanol in some miscarriages. It identifies a difficulty encountered from earlier attendance in the miscarrying group so that a later study could circumvent it and perhaps lead to a case for funding of a prospective enquiry into the dose-response relations of any association that might exist.  相似文献   
2.
The UK Northern Region Fetal Abnormality Survey was notified of 572 suspected fetal abnormalities in 1987. Of these, 265 (46%) had pediatric surgical implications. Because the registry traces the postnatal outcome of each notification and records congenital abnormalities diagnosed postnatally, it is possible to measure both sensitivity and selectivity of antenatal diagnosis of fetal abnormalities. Cases were divided into five groups: diaphragmatic hernia, abdominal wall defects, intestinal anomalies, neural tube defects, and urological anomalies. Each group comprised cases that were unsuspected, suspected but not confirmed, and suspected and confirmed. Sensitivity was highest in the urological group, but 30% of the notified cases were unconfirmed so selectivity was higher in the abdominal wall and neural tube groups. None of the diaphragmatic hernias and only 14.3% of the intestinal anomalies were correctly suspected. Only 13.5% of all neural tube defects were treated surgically. The Survey has improved cooperation and communication between specialists concerned with the management of fetal abnormalities and this in turn has improved patient care.  相似文献   
3.
4.
5.
Femoral shaft fracture treatment in patients age 6 to 16 years   总被引:2,自引:0,他引:2  
Traction followed by spica casting, the one method used to treat femoral shaft fractures in children that was used in the past, has given way to a multiplicity of methods today. To evaluate the morbidity and costs of these various methods, 85 fractures in 81 patients age six to 16 years were evaluated. Early spica casting gave excellent results with low complications and low costs. All surgical treatments cost approximately the same: 3 times the cost of early spica casting and equivalent to traction followed by spica casting. Intramedullary flexible rods resulted in quicker healing and return to full weight bearing than did external fixation, which had the highest complication rate. One case of avascular necrosis in an 11-year-old girl treated with a reamed intramedullary rod suggests that this method is best reserved for children at or near skeletal maturity.  相似文献   
6.
7.
The complete protocol for the treatment of breast cancer at the Institute Gustave Roussy, Villejuif, France, is presented. Treatment is carried out by a multidisciplinary committee dealing with nearly one thousand new breast cancers annually. The protocol is based on initial classification by the T.N.M. system and by characteristics indicating "aggressive biological behaviour". Patients are separated into three broad groups for which the mainstays of treatment are surgery, radiotherapy, and chemotherapy. The rationale and results of the protocol are presented.  相似文献   
8.
Sexual and nonsexual modes of transmission of human herpesvirus 8 (HHV8) have been suggested, but specific routes remain unclear. Therefore, the objective of this study was to assess risk factors for HHV8 seropositivity and determine specific sexual practices associated with HHV8 seroconversion. Sera from 1,458 homosexual men (Amsterdam Cohort Study, 1984-1996) were tested for antibodies to HHV8 with a modified version of an enzyme immunoassay, using recombinant HHV8 lytic phase capsid (ORF65) and latent phase nuclear (ORF73) proteins. HHV8 seroprevalence at study entry was 20.9% (305/1,458); was highest among those with positive human immunodeficiency virus (HIV) status, no steady partner, and southern European or Latin American nationality; and increased with older age and higher number of sexual partners. During follow-up, 215 men seroconverted for HHV8 (incidence: 3.6/100 person-years). Both prevalence and incidence rates remained more or less stable during the study period. Orogenital insertive sex (odds ratio (OR) = 5.95; 95% confidence interval (CI): 2.88, 12.29) or orogenital receptive sex (OR = 4.29; 95% CI: 2.11, 8.71) with more than five partners in the past 6 months, older age (OR = 2.89; 95% CI: 1.13, 7.34, when older than 45 years), and preceding HIV infection (OR = 2.47; 95% CI: 1.53, 3.99) were independent predictors for HHV8 seroconversion. The authors found strong evidence for orogenital transmission of HHV8 among homosexual men.  相似文献   
9.
The derivation of safe levels of exposure in humans for compounds that are assumed to cause threshold toxicity has relied on the application of a 100-fold uncertainty factor to a measure for the threshold, such as the no observed adverse effect level (NOAEL) or the benchmark dose (BMD). This 100-fold safety factor consists of the product of two 10-fold factors allowing for human variability and interspecies differences. The International Programme on Chemical Safety has suggested the subdivision of these 10-fold factors to allow for variability in toxicokinetics and toxicodynamics. This subdivision allows the replacement of the default uncertainty factors with a chemical-specific adjustment factor (CSAF) when suitable data are available. This short review describes potential options to refine safety factors used in risk assessment, with particular emphasis on pathway-related uncertainty factors associated with variability in kinetics. These pathway-related factors were derived from a database that quantified interspecies differences and human variability in phase I metabolism, phase II metabolism, and renal excretion. This approach allows metabolism and pharmacokinetic data in healthy adults and subgroups of the population to be incorporated in the risk-assessment process and constitutes an intermediate approach between simple default factors and chemical-specific adjustment factors.  相似文献   
10.
BACKGROUND: Mammographic screening for breast cancer not only reduces the overall mortality from breast cancer but allows greater opportunities for breast-conserving operations. The predicted degree of breast conservation is not being realized, but is increasing in centres that have published their results. METHODS: The operative management of breast cancers diagnosed by BreastScreen Central and Eastern Sydney Screening and Assessment Service were compared between two time periods: January 1988-December 1992 (group 1) and January 1993-December 1995 (group 2). The rate of breast conservation, and other data were compared between the two periods. An attempt was made with multivariate analysis to identify some of the factors that made mastectomy rather than conservation more likely. RESULTS: There were 723 cancers detected that were suitable for analysis (group 1, n = 273; group 2, n = 450). In group 1 the breast conservation rate was 42.9%; this increased significantly to 60.4% in group 2 (P < 0.001). The data were examined to determine if there was any other factor that had changed over the time periods which might account for the increased rate of breast conservation. The use of pre-operative diagnostic techniques such as fine needle aspirate cytology and core biopsy increased significantly. Multivariate analysis comparing the differences in patient age, diagnostic technique, tumour type, grade, size, location and lymph node status, both independently and compositely did not account for the increase in breast conservation in group 2. CONCLUSION: The increase in breast conservation is due to other factors such as the surgeons' approach and patient attitude. The use of pre-operative, minimally invasive tissue sampling techniques is increasing.  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