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   526篇
  免费   18篇
  国内免费   1篇
儿科学   52篇
妇产科学   4篇
基础医学   47篇
口腔科学   12篇
临床医学   58篇
内科学   112篇
皮肤病学   7篇
神经病学   7篇
特种医学   148篇
外科学   18篇
综合类   7篇
预防医学   25篇
眼科学   3篇
药学   29篇
肿瘤学   16篇
  2024年   1篇
  2021年   2篇
  2020年   1篇
  2018年   7篇
  2017年   3篇
  2016年   2篇
  2015年   6篇
  2014年   11篇
  2013年   17篇
  2012年   5篇
  2011年   7篇
  2010年   26篇
  2009年   19篇
  2008年   5篇
  2007年   5篇
  2006年   5篇
  2005年   19篇
  2004年   9篇
  2003年   10篇
  2002年   4篇
  2001年   10篇
  2000年   11篇
  1999年   9篇
  1998年   32篇
  1997年   27篇
  1996年   25篇
  1995年   26篇
  1994年   26篇
  1993年   19篇
  1992年   7篇
  1991年   7篇
  1990年   12篇
  1989年   17篇
  1988年   18篇
  1987年   14篇
  1986年   9篇
  1985年   17篇
  1984年   8篇
  1983年   9篇
  1982年   20篇
  1981年   12篇
  1980年   10篇
  1979年   1篇
  1978年   4篇
  1977年   8篇
  1976年   14篇
  1975年   8篇
  1973年   1篇
排序方式: 共有545条查询结果,搜索用时 15 毫秒
101.
AIMS: Few smokers who try to quit smoking use smoking cessation treatment (SCT), and cost could be one factor. To increase the number of successful quitters, we assessed whether financial reimbursement for SCT would encourage the use of SCT and would as a result increase the 6-month point abstinence rate. SETTING AND PARTICIPANTS: We recruited smokers aged over 18 years from a random sample of Dutch inhabitants insured by one health insurance company. INTERVENTION AND DESIGN: The smokers were assigned randomly to the intervention group (n = 632) or control group (n = 634). Respondents in the intervention group received an offer of reimbursement for nicotine replacement therapy, bupropion and behavioural counselling. No reimbursement was offered to the control group. To preclude a change of behaviour due to disappointment in the control group, we used a randomized consent design. FINDINGS: During the reimbursement period, 10.8% smokers in the intervention group reported having used SCT compared with 4.1% in the control group (OR = 2.9, 95% CI 1.8-4.7). In the intervention group, 23.4% smokers tried to stop compared with 20.8% in the control group (OR = 1.2, 95% CI 0.9-2.4). After 6 months, the biochemically validated 7-day point prevalence abstinence rate was 5.5% in the intervention group and 2.8% in the control group (OR = 2.3, 95% CI 1.2-4.1). CONCLUSIONS: Reimbursement for SCT seems efficacious in increasing the use of SCT and may double the number of successful quitters.  相似文献   
102.
BACKGROUND: The observations that smokers with chronic obstructive pulmonary disease (COPD) are at increased risk of depression and that nicotine may have antidepressant effects and regulate mood provide a rationale for the use of antidepressant drugs for smoking cessation in patients with COPD. No clinical trial has studied the efficacy of bupropion hydrochloride and nortriptyline hydrochloride for smoking cessation in this patient population, to our knowledge. METHODS: In a placebo-controlled double-dummy randomized trial, 255 adults at risk for COPD or with COPD were prescribed sustained-release bupropion (bupropion SR) (150 mg twice daily) or nortriptyline (75 mg once daily) for 12 weeks. All patients received smoking cessation counseling. The main outcome measure was prolonged abstinence from smoking from week 4 to week 26 after the target quit date. RESULTS: The use of bupropion SR and nortriptyline resulted in higher prolonged abstinence rates compared with placebo, although only the difference between bupropion SR and placebo was statistically significant (differences with placebo, 13.1% [95% confidence interval, 1.2%-25.1%] for bupropion SR and 10.2% [95% confidence interval, -1.7% to 22.2%] for nortriptyline). In patients with COPD, bupropion SR and nortriptyline seem efficacious in achieving prolonged abstinence (differences with placebo, 18.9% [95% confidence interval, 3.6%-34.2%] for bupropion SR and 12.9% [95% confidence interval, -0.8% to 26.4%] for nortriptyline). In participants at risk for COPD, no statistically significant differences with placebo in prolonged abstinence rates were found. CONCLUSIONS: Bupropion SR treatment is an efficacious aid to smoking cessation in patients with COPD. Nortriptyline treatment seems to be a useful alternative.  相似文献   
103.
104.
The EDTNA/ERCA survey of the treatment of water for dialysis was the third project organised through the Collaborative Research Programme (CRP). Data was collected from 69 haemodialysis facilities in 14 countries. Water quality in European dialysis units was mainly self‐regulated. The majority of centres aimed to meet the requirements of the European Pharmacopoeia, but only 50% carried out tests to check compliance. All facilities used reverse osmosis to treat water for dialysis, most also used softening and carbon adsorption. There was a wide variation in policies for the maintenance of carbon filters, and for the control and monitoring of contamination in the distribution system. Endotoxin tests carried out in 27 facilities showed that higher levels of contamination are associated with systems that are infrequently disinfected, and also with older system designs. The survey indicated that guidelines for water treatment are urgently needed. EDTNA/ERCA guidelines for microbiological monitoring are now being drafted, additional guidelines are under consideration.  相似文献   
105.
ObjectiveTo ascertain the socio-cultural factors influencing the rate of utilization of insecticide treated bed nets (ITNs) in a malaria endemic city of Makurdi, north central Nigeria.MethodsThe study was cross-sectional in nature using systematic sampling method to identify households. Both quantitative and qualitative data was generated from adult women using structured and semi structured questionnaires, and focused group discussions (FGDs) to obtain information on rate and patterns of utilization of ITNs. Information such as age, educational level, marital status, awareness or otherwise of the existence of malaria, and factors influencing rate of ownership and utilization of ITNs were obtained. FGDs were used to obtain qualitative information on rate of utilization of ITNs not captured in the questionnaires. Data obtained was analysed using Epi Info 6 statistical software.ResultsAmong the respondents interviewed, 97.0% (2 013/2 075) were aware of existence of malaria and 87.0% of these (1 751/2 013) would associate it with mosquitoes. The rate of ownership of any bed net, ITNs and untreated bed nets (UTNs) was 25.1%, 17.0% and 8.3%, respectively. Utilization of ITNs among children was 30.0% (112/373) and UTNs 12.9% (48/373). Positive contributors to ITNs utilization were literacy, enhanced economy, experience of marriage, and being gainfully employed (P<0.05); while negative contributors were ignorance, poverty and some cultural beliefs and values.ConclusionsA more synchronized advocacy should be carried out on the potential benefits of ITNs utilization and sustained. Also ITNs should be made available to the people of the community at minimal or no cost.  相似文献   
106.
The goal of this phase II multicenter clinical trial was to evaluate a new intensive chemotherapy program for adults with untreated acute lymphoblastic leukemia (ALL) and to examine prospectively the impact of clinical and biologic characteristics on the outcome. One hundred ninety-seven eligible and evaluable patients (16 to 80 years of age; median, 32 years of age) received cyclophosphamide, daunorubicin, vincristine, prednisone, and L-asparaginase; 167 patients (85%) achieved a complete remission (CR), 13 (7%) had refractory disease, and 17 (9%) died during induction. A higher CR rate was observed in younger patients (94% for those < 30 years old, 85% for those 30 to 59 years old, and 39% for those > or = 60 years old, P < .001) and in those who had a mediastinal mass (100%) or blasts with a T-cell immunophenotype. Eighty percent of B-lineage and 97% of T-cell ALL patients achieved a CR (P = .01). The coexpression of myeloid antigens did not affect the response rate or duration. Seventy percent of those with cytogenetic or molecular evidence of the Philadelphia (Ph) chromosome and 84% of those without such evidence achieved a CR (P = .11). Patients in remission received multiagent consolidation treatment, central nervous system prophylaxis, late intensification, and maintenance chemotherapy for a total of 24 months. After a median follow-up time of 43 months, the median survival for all 197 patients is 36 months; the median remission duration for the 167 CR patients is 29 months. Favorable pretreatment characteristics relative to remission duration or survival are younger age, the presence of a mediastinal mass or lymphadenopathy, a white blood cell count (WBC) less than 30,000/microL, L1 morphology, T or TMy immunophenotype, and the absence of the Ph chromosome. The estimates of the proportion surviving at 3 years are 69% for patients less than 30 years old, 39% for those 30 to 59 years old, 89% for those who had a mediastinal mass, 59% with WBC less than 30,000/microL, 63% with L1 morphology, 69% for T or TMy antigen expression, and 62% for those who lack the Ph chromosome. Fifteen patients (8%) had no unfavorable prognostic factors and have an estimated probability of survival at 5 years of 100% (95% confidence interval, 77% to 100%). This intensive chemotherapy regimen produces a high remission rate and a high proportion of durable remissions in adults with ALL.  相似文献   
107.
Corzo  D; Yunis  JJ; Salazar  M; Lieberman  JA; Howard  A; Awdeh  Z; Alper  CA; Yunis  EJ 《Blood》1995,86(10):3835-3840
Genes of the major histocompatibility complex (MHC) have been associated with susceptibility to drug-induced adverse reactions. We previously found that clozapine-induced agranulocytosis (CA) is associated with the HLA-DRB1*0402, DRB4*0101, DQB1*0302, DQA1*0301 haplotype in Ashkenazi Jewish patients and with the HLA-DRB1*1601, DRB5*02, DQB1*0502, DQA1*0102 haplotype in non-Jewish patients. In the present study, we tested the hypothesis that the variants of the heat- shock protein 70 (HSP-70) encoded by the HSP-70 loci located within the MHC region and known to be involved in apoptosis and regulation of cell proliferation could play an important role in molecular mechanisms of CA. First, we analyzed HSP70-2 polymorphism in risk-associated haplotypes from HLA homozygous cells and normal individuals and confirmed that the HSP70-2 9-kb variant was associated invariably with DR4 (HLA-DRB1*0402, DQB1*0302) and DR2 (HLA-DRB1*01601, DQB1*0502, DQA1*0102 and HLA-DRB1*1501, DQB1*0602) haplotypes, which were the haplotypes found increased in Jewish and non-Jewish patients with CA, respectively. The 9.0-kb variant was also found to be associated with HLA-B44, DRB1*0401 and HLA-B44, DRB1*07 haplotypes. Second, in patients with CA (12 Ashkenazi Jewish and 20 non-Jewish patients), HSP70-1 A and HSP70-2 9.0-kb variants were associated with the MHC haplotypes found by us to be markers of susceptibility to CA. The clozapine-treated control group had an excess number of HSP70-1 C and HSP70-2 8.5-kb variants, consistent with genetic resistance to CA associated with those variants. This finding supports our hypothesis that a dominant gene within the MHC region (marked by HSP70-1 and HSP70-2), but not necessarily HLA, is associated with CA in two different ethnic groups.  相似文献   
108.
Crosslineage T-cell receptor delta (TCR delta) rearrangements are widely used as tumor markers for the follow up of minimal residual disease in childhood B-precursor acute lymphoblastic leukemia (ALL) by polymerase chain reaction (PCR). The major drawback of this approach is the risk of false-negative results due to clonal evolution. We investigated the stability of V delta 2D delta 3 rearrangements in a group of 56 childhood B-precursor ALL patients by PCR and Southern blot analysis. At the PCR level, V delta 2D delta 3-to-J alpha rearranged subclones (one pathway for secondary TCR delta recombination) were demonstrated in 85.2% of V delta 2D delta 3-positive patients tested, which showed that small subclones are present in the large majority of patients despite apparently monoclonal TCR delta Southern blot patterns. Sequence analysis of V delta 2D delta 3J alpha rearrangements showed a biased J alpha gene usage, with HAPO5 and J alpha F in 26 of 32 and 6 of 32 clones, respectively. Comparison of V delta 2D delta 3 rearrangement status between diagnosis and first relapse showed differences in seven of eight patients studied. In contrast, from first relapse onward, no clonal changes were observed in six patients studied. To investigate the occurrence of crosslineage TCR delta rearrangements in normal B and T cells, fluorescence-activated cell sorter-sorted peripheral blood CD19+/CD3- and CD19-/CD3+ cell populations from three healthy donors were analyzed. V delta 2D delta 3 rearrangements were detected at low frequencies in both B and T cells, which suggests that V delta 2-to-D delta 3 joining also occurs during normal B-cell differentiation. A model for crosslineage TCR delta rearrangements in B-precursor ALL is deduced that explains the observed clonal changes between diagnosis and relapse and is compatible with multistep leukemogenesis of B-precursor ALL.  相似文献   
109.
Lee  EJ; Schiffer  CA 《Blood》1987,70(6):1727-1729
Serial evaluations of lymphocytotoxic antibody (LCTAb) and responsiveness to random donor platelet transfusion were reviewed in 234 patients who had developed LCTAb at some time during their treatment course. Seventy (30%) of these patients had significant falls in antibody levels. In 44 patients these declines occurred after further antigenic exposure was reduced either because no transfusions were administered or only histocompatible platelets were transfused. Forty patients with declines in LCTAb levels who were previously refractory to platelet transfusion were rechallenged with random donor platelets. Thirty-four of 35 clinically evaluable patients had good responses to these unmatched transfusions for 2 weeks to 36 months, and in 21 patients antibody did not return despite repeated transfusions. Thus, serial LCTAb measurements are helpful in the management of alloimmunized patients. Many patients will have decreases or a loss of LCTAb, either permanently or transiently, and can be successfully supported with more easily available unmatched random donor platelet transfusions.  相似文献   
110.
Masouredis  SP; Branks  MJ; Victoria  EJ 《Blood》1987,70(3):710-715
IgG autoantibodies eluted from RBCs of antiglobulin positive normal blood donors contained at least two antibody populations, an IgG autoantibody (Ab 1), and an IgG population (Ab 2) that agglutinated RBCs coated with some Rh(D) alloantibodies. Eight of 24 autoantibody eluates tested agglutinated 3 of 10 anti-Rh(D) sensitized RBCs. The agglutinating activity was inhibited specifically by preincubation of the autoantibody eluate with the reactive anti-D. The reaction did not require the Fc domain of the anti-Rh(D), since autoantibody eluates agglutinated RBCs coated with F(ab')2 prepared from the reactive anti-D sera. These findings indicate that the RBCs of some antiglobulin- positive blood donors contain an immunoglobulin auto-antiidiotype (Ab 2) against the RBC autoantibody (Ab 1) which is demonstrable through its cross-reactivity with selected Rh(D) alloantibodies. Identification of auto-antiidiotypes in RBC autoimmunity lends support to the idiotype- antiidiotype network hypothesis of immune regulation and is consistent with the bizarre and complex serology of autoimmune hemolytic anemia. The absence of clinical hemolysis in antiglobulin-positive normal blood donors suggests that immunoglobulin idiotype-antiidiotype interactions may play a role in modulating the effects of RBC autoimmunity.  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