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   230篇
  免费   21篇
儿科学   4篇
妇产科学   10篇
基础医学   38篇
口腔科学   3篇
临床医学   22篇
内科学   64篇
皮肤病学   8篇
神经病学   39篇
特种医学   1篇
外科学   20篇
综合类   2篇
预防医学   19篇
眼科学   2篇
药学   13篇
中国医学   1篇
肿瘤学   5篇
  2022年   3篇
  2021年   5篇
  2020年   4篇
  2019年   4篇
  2017年   1篇
  2016年   6篇
  2015年   4篇
  2013年   7篇
  2012年   7篇
  2011年   11篇
  2010年   9篇
  2008年   13篇
  2007年   13篇
  2006年   8篇
  2005年   13篇
  2004年   7篇
  2003年   14篇
  2002年   7篇
  2001年   9篇
  2000年   11篇
  1999年   11篇
  1998年   3篇
  1997年   4篇
  1995年   6篇
  1994年   3篇
  1993年   5篇
  1992年   12篇
  1991年   9篇
  1990年   9篇
  1989年   6篇
  1988年   6篇
  1987年   3篇
  1986年   7篇
  1985年   5篇
  1980年   2篇
  1979年   1篇
  1978年   2篇
  1977年   1篇
排序方式: 共有251条查询结果,搜索用时 15 毫秒
1.
We examined 161 human tissue samples using the spot hybridization technique with nonradioactive labeled DNA probes of human papillomavirus (HPV). Whole cells were spotted on nitrocellulose filters; DNA of the cells was denatured and fixed to the filter. Then the DNA spots were hybridized to nonradioactive labeled DNA and monitored by a sandwich immunoenzymatic reaction. This technique is simple, sensitive, specific, requires no special equipment, and can be used in clinical settings. HPV DNA was found in 92% of samples in which, on the basis of histologic and colposcopic criteria, its presence was suspected, as well as in 31 samples where it was not suspected.  相似文献   
2.
Epidermal growth factor excretion in burned rats   总被引:3,自引:0,他引:3  
Evidence for epidermal growth factor (EGF) involvement in the physiological response to burns was sought from urinary levels of EGF, urea and creatinine in male rats using a standardized thermal skin injury model (25 per cent body surface) and treated with fluid resuscitation. Postmortem, the skin lesions were studied by microscopy to guarantee the absence of inflammatory complications. Statistically significant differences were observed in body weight, urea and creatinine excretion when compared to the basal values. When EGF excretion results were evaluated as raw data (expressed as ng/mg of creatinine or ng/day) compared to basal levels, no statistically significant differences were observed. However, when the results were expressed as percentage increases with respect to the basal values, a statistically significant increase was found over the first 7 days postinjury (P = 0.029).  相似文献   
3.
The aim of this study was to investigate the attitudes of doctors performing surgery to the HIV antibody testing of surgical patients. Fifty of eighty (62.5%) doctors performing surgery who are working in two London teaching hospitals returned completed anonymous postal questionnaires. Sixty-six per cent of the sample would like some form of compulsory testing of pre-operative patients, although most of them feel that this is only necessary for patients considered to be in 'high-risk groups'. Eighty-four per cent believe that this would ensure their safety from infection during surgery. Forty-eight per cent agreed with testing patients without their consent. Results suggest that most of the doctors performing surgery in this study agree with compulsory HIV antibody testing of pre-operative patients in the belief that this would protect them from infection during surgery. The problems associated with compulsory testing and relying on such testing in order to protect doctors from infection during surgery are discussed.  相似文献   
4.
Antikinetochore antibodies and fluorescence in situ hybridizationwith an alphoid centromeric probe were applied to the cytokinesis-blockmicronucleus (MN) assay to study the suitability of these methodologiesto detect clastogenic/aneugenic activity in isolated human lymphocytes.The chemicals selected for this study were the herbicide alachlor,the clastogen mitomycin-C (MMC), and the aneugen vinblastinesulphate (VBL). Futhermore, MN frequencies obtained from slidesstained with May–Grünwald–Giemsa (MGG) andwith the DNA fluorochrome 4', 6'diamidino-2-phenylindole (DAPI)were compared to check if the DNA-specific DAPI facilitateda more accurate recording of MN than the unspecific MGG. Theresults showed that the detection of kinetochores (KC) or centromeres(CM) within MN are equally reliable and sensitive techniquesto study the mode of action of clastogenic and aneugenic agents.The comparison of CM and KC detection in control cultures suggestedthat up to 17% of spontaneous chromosomecontaining MN may bedue to KC disruption, whereas the majority are caused by dysfunctionin other components of the mitotic apparatus. Alachlor (7.5–20µg/ml) and MMC (0.6 µM) acted as pure clastogenswithout aneugenic activity, inducing exclusively KC- and CM-negativeMN. VBL produced primarily KC- and CM-positive MN, in accordancewith its known mechanism of action. A comparison between CMand KC data in the VBL treatment suggested that some 7% of KC-containingMN may not be detected by the probe. The frequencies of MN weregenerally higher in slides stained with DAPI than in those stainedwith MGG, especially in controls and clastogen-treated cultures.This finding probably reflects an underestimation with MGG ofsmall, light MN indistinguishable from the cytoplasmic background. 4To whom correspondence should be addressed  相似文献   
5.
BACKGROUND: We carried out a large randomized trial of a brief form of cognitive therapy, manual-assisted cognitive behaviour therapy (MACT) versus treatment as usual (TAU) for deliberate self-harm. METHOD: Patients presenting with recurrent deliberate self-harm in five centres were randomized to either MACT or (TAU) and followed up over 1 year. MACT patients received a booklet based on cognitive behaviour therapy (CBT) principles and were offered up to five plus two booster sessions of CBT from a therapist in the first 3 months of the study. Ratings of parasuicide risk, anxiety, depression, social functioning and global function, positive and negative thinking, and quality of life were measured at baseline and after 6 and 12 months. RESULTS: Four hundred and eighty patients were randomized. Sixty per cent of the MACT group had both the booklet and CBT sessions. There were seven suicides, five in the TAU group. The main outcome measure, the proportion of those repeating deliberate self-harm in the 12 months of the study, showed no significant difference between those treated with MACT (39%) and treatment as usual (46%) (OR 0.78, 95% CI 0.53 to 1.14, P=0.20). CONCLUSION: Brief cognitive behaviour therapy is of limited efficacy in reducing self-harm repetition, but the findings taken in conjunctin with the economic evaluation (Byford et al. 2003) indicate superiority of MACT over TAU in terms of cost and effectiveness combined.  相似文献   
6.
The African pygmy mice, subgenus Nannomys, constitute the most speciose lineage of the genus Mus with 19 recognized species. Although morphologically very similar, they exhibit considerable chromosomal diversity which is here confirmed and extended by the G-banding analysis of 65 mice from West and South Africa. On the basis of their karyotype and distribution area, the specimens were assigned to at least five species. Extensive differentiation both within and between species was observed that involved almost exclusively Robertsonian translocations, 23 of which are newly described. Two of the rearrangements were sex chromosome-autosome translocations, associated in some cases with partial deletions of the X or Y chromosomes. Several authors have predicted that the highly deleterious effect of this rearrangement would be reduced if the sex and autosomal segments were insulated by a block of centromeric heterochromatin. The C-banding analyses performed showed that among the species carrying X-autosome translocations, one followed the expected pattern, while the other did not. In this case, functional isolation of the sex and autosome compartments must involve other repetitive sequences or genomic traits that require further molecular characterization. Such studies will provide insight into the causes and consequences of the high diversity of sex chromosome rearrangements in this subgenus.  相似文献   
7.
Background. Klippel-Feil syndrome (KFS) is characterised by congenital vertebral fusion of the cervical spine and a wide spectrum of associated anomalies. KFS has often been considered a sporadic syndrome. However, since the publication of the original KFS classification early this century, a number of KFS families have indicated heterogeneity complicated by a broad range of variable expression. Objective. The two major objectives of this study were (1) to identify differences and similarities in the postnatal appearance, morphology, position and inheritance of vertebral fusions within and between KFS families and (2) to establish a new KFS classification focussed on KFS aetiology. Materials and methods. Vertebral fusions were assessed via spinal radiography. Chromosomal karyotypes were performed using routine cytogenetics. Results. The medical histories of three KFS families are presented. The postnatal time, position and appearance of vertebral fusions, associated anomalies and mode of inheritance were different for the three KFS families. Four classes of KFS are described in a comprehensive classification table that allays much of the uncertainty arising from KFS heterogeneity and variable expression. Conclusion. We have described four different KFS classes (KF1–4) within a comprehensive classification that addresses KFS genetic heterogeneity. The position of vertebral fusions in the cervical spine and their incidence within affected families are delineating features of KFS. Received: 10 October 1997 Accepted: 20 April 1998  相似文献   
8.
A group of 22 individuals with HIV infection who had made acts of self-harm were compared with a sex and age-matched control group of individuals without known HIV infection who had also being involved in acts of deliberate self-harm (DSH). Compared with all DSH individuals referred to the deliberate self-harm service during the same period. men were over-represented amongst HIV subjects. Compared with matched controls, HIV subjects were more likely to include gay/bisexual men, and not be employed. Individuals with HIV infection were more likely to be receiving outpatient psychiatric care at the time of DSH. and to have received it in the past A diagnosis of depression was given mom frequently to HIV subjects, while alcohol misuses was more often diagnosed in controls. Concerns about their physical health were prominent amongst HIV seropositives. Psychiatric follow-up was offered to HIV subjects more often than to controls. The results indicate that HIV disease is a potential contributing factor to deliberate self-harm. and highlight the need for efforts to identify individuals with HIV infection at risk of deliberate self-harm, ant to develop effective interventions to prevent suicidal behaviour in this group of individuals.  相似文献   
9.
Tick-borne encephalitis (TBE) virus is the most important human pathogen transmitted by ticks in Eurasia. Inactivated vaccines are available but require multiple doses and frequent boosters to induce and maintain immunity. Thus far, the goal of developing a safe, live attenuated vaccine effective after a single dose has remained elusive. Here we used a replication-defective (single-cycle) flavivirus platform, RepliVax, to generate a safe, single-dose TBE vaccine. Several RepliVax-TBE candidates attenuated by a deletion in the capsid gene were constructed using different flavivirus backbones containing the envelope genes of TBE virus. RepliVax-TBE based on a West Nile virus backbone (RV-WN/TBE) grew more efficiently in helper cells than candidates based on Langat E5, TBE, and yellow fever 17D backbones, and was found to be highly immunogenic and efficacious in mice. Live chimeric yellow fever 17D/TBE, Dengue 2/TBE, and Langat E5/TBE candidates were also constructed but were found to be underattenuated. RV-WN/TBE was demonstrated to be highly immunogenic in Rhesus macaques after a single dose, inducing a significantly more durable humoral immune response compared with three doses of a licensed, adjuvanted human inactivated vaccine. Its immunogenicity was not significantly affected by preexisting immunity against WN. Immunized monkeys were protected from a stringent surrogate challenge. These results support the identification of a single-cycle TBE vaccine with a superior product profile to existing inactivated vaccines, which could lead to improved vaccine coverage and control of the disease.  相似文献   
10.
Journal of Neurology - Parkinson’s disease (PD) patients with impulse control disorders (ICD) frequently report hypersensitivity to rewards. However, a few studies have explored the...  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