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   731篇
  免费   29篇
  国内免费   1篇
耳鼻咽喉   17篇
儿科学   24篇
妇产科学   13篇
基础医学   120篇
口腔科学   12篇
临床医学   57篇
内科学   76篇
皮肤病学   10篇
神经病学   36篇
特种医学   24篇
外科学   128篇
综合类   8篇
预防医学   46篇
眼科学   4篇
药学   60篇
中国医学   1篇
肿瘤学   125篇
  2023年   3篇
  2022年   1篇
  2021年   16篇
  2020年   9篇
  2019年   20篇
  2018年   21篇
  2017年   15篇
  2016年   16篇
  2015年   24篇
  2014年   29篇
  2013年   41篇
  2012年   50篇
  2011年   58篇
  2010年   41篇
  2009年   30篇
  2008年   40篇
  2007年   22篇
  2006年   20篇
  2005年   41篇
  2004年   28篇
  2003年   33篇
  2002年   18篇
  2001年   16篇
  2000年   7篇
  1999年   12篇
  1998年   5篇
  1997年   7篇
  1996年   5篇
  1995年   3篇
  1994年   3篇
  1993年   4篇
  1992年   5篇
  1991年   7篇
  1990年   12篇
  1989年   7篇
  1988年   16篇
  1987年   12篇
  1986年   8篇
  1985年   6篇
  1984年   10篇
  1983年   8篇
  1982年   7篇
  1981年   4篇
  1980年   5篇
  1979年   7篇
  1978年   3篇
  1977年   1篇
  1976年   1篇
  1975年   3篇
  1974年   1篇
排序方式: 共有761条查询结果,搜索用时 93 毫秒
1.
There is a sharp difference in how one views TCR structure–function–behaviour dependent on whether its recognition of major histocompatibility complex‐encoded restriction elements (R) is germline selected or somatically generated. The generally accepted or Standard model is built on the assumption that recognition of R is by the V regions of the αβ TCR, which is not driven by allele specificity, whereas the competing model posits that recognition of R is allele‐specific. The establishing of allele‐specific recognition of R by the TCR would rule out the Standard model and clear the road to a consideration of a competing construct, the Tritope model. Here, the case for allele‐specific recognition (germline selected) is detailed making it obvious that the Standard model is untenable.  相似文献   
2.
3.
We carried out a postal survey of randomly selected orthopaedic surgeons in the North East of England, enquiring about outpatient follow-up patterns after primary total hip replacement. The aim was to compare and contrast the number and timing of appointments as well as assess the involvement of orthopaedic nurse practitioners (ONP). The number of visits in the first post-operative year varied between two and five. The average duration before the first, second and third follow-up was 5 weeks, 4 months and 13 months respectively. Ninety-three percent of the consultants follow their patients indefinitely. For the patients who are followed for life, 71% are seen in the ONP clinic and 29% in the consultant clinic. Fifty percent of the consultants sub-specialising in lower limb arthroplasty follow their patients up to 1 year, after which the care is taken over by an orthopaedic nurse practitioner, compared to 70% of the general orthopaedic consultants. With increasing number of total hip replacement operations being performed, guidelines and consistency would be desirable in order to make the follow-up of patients efficient in terms of the time and cost.  相似文献   
4.
In the present paper fifty patients with symptoms of inner ear dysfunction, primarily deafness, vertigo or both, were subjected to a detailed history, pure tone audiometry and caloric tests. A detailed serum lipid analysis was done of all the patients. It was concluded that atherosclerotic disease of the labyrinthine vessels usually affects patients above forty years of age. It occurs bilaterally. Commonly both the cochlear and vestibular components are involved. Raised serum total cholesterol, L.D.L. cholesterol levels and hypertension, are more contributory as risk factors in its development.  相似文献   
5.
Cytochemical analysis of leukemic blasts from 46 patients with acute myeloblastic M2 leukemia (according to the FAB classification) was performed before and after cytostatic therapy, and compared with findings obtained in 20 age- and sex-matched control subjects. Cytochemical findings for myeloperoxidase (MPO), Sudan black B, acid phosphatase and alpha-naphthyl-acetate esterase (ANAE) were related to the achievement of the first complete remission (CR),i.e. data were compared after the patients had been divided into CR and non-CR groups. The analysis clearly showed that a high proportion of myeloperoxidase- and, to a lesser extent, Sudan black B-positive blasts before treatment may have constituted a significantly unfavourable prognostic factor.  相似文献   
6.
Incentives and disincentives in the Indian family welfare program   总被引:1,自引:0,他引:1  
The Indian family welfare program has offered financial incentives since the early 1960s to both family planning motivators and acceptors of sterilization and the IUD. This article reviews the available evidence regarding the impact of incentives on the quality and quantity of family planning services in India. Administrative concerns related to the implementation of incentive programs are discussed, and the current debate on disincentives, as well as the brief period when disincentives were used, is summarized. The studies reviewed, though few in number and varying in quality and methodology, indicate that incentives to acceptors help to increase the level of contraceptive acceptance, especially when they are part of a well designed strategy of service delivery and client motivation. Incentives do not appear to have an adverse effect on quality of services and acceptors, and they do not seem to influence method choice. Disincentives, if they are used, should not impinge on fundamental individual rights of either the parents or the child.  相似文献   
7.
A phase II study of a new anthracycline anti-cancer antibiotics, epirubicin (EPI), was undertaken in 71 patients with urothelial malignancies; 40 with advanced urothelial malignancies and 31 with superficial bladder cancer. Out of them 32 patients with advanced stage of urothelial cancer were evaluated for the systemic use of EPI, while 30 patients with superficial bladder cancer for intravesical use. Intravenous administration of this new anticancer antibiotic, at a dosage of 60 mg/m2 every three weeks, showed the response rate of 20.0% for advanced bladder cancer and 14.3% for renal pelvic and ureteral tumors. In cases of superficial bladder cancer, at a dosage of 60 mg/30 ml X 3 day every week in principal, the response rate was 66.7%. Eight out of 30 patients showed complete disappearance of the tumor. Twelve patients also showed more than 50% tumor regression. As for adverse effects no serious cardiotoxicity was demonstrated. Anorexia and other gastrointestinal side effects, such as nausea and vomiting, were also seen. Alopecia and myelosuppression were the major adverse effects among patients with systemic EPI administration. With intravesical use of EPI, cystitis syndrome was the major toxicity. However, no systemic side effects were noted in these cases. In conclusion, EPI was assumed to be effective for the treatment of advanced urothelial tumors and superficial bladder cancer.  相似文献   
8.
The role of hepatitis B virus (HBV) in carcinogenesis of hepatitis B surface antigen (HBsAg)-negative, anti-hepatitis C virus (anti-HCV)-positive hepatocellular carcinoma (HCC) remains unknown. To investigate the state of HBV DNA in such HCC, HBV DNA was examined by polymerase chain reaction (PCR) between HBV DNA and human Alu sequence (HBV-Alu PCR), which could detect integrated form of HBV DNA only, and by conventional HBV PCR, which could detect both integrated and episomal forms of HBV DNA. In all the 17 HBsAg-positive HCC, HBV DNA was detected by both HBV-Alu PCR method and conventional HBV PCR method. By contrast, in HBsAg-negative, anti-HCV-positive cases, HBV DNA was detected in 10 of 21 (47.6%) by conventional HBV PCR and in none of 21 (0%) by HBV-Alu PCR method. Thus, integrated form of HBV DNA was not found in most HbsAg-negative, anti-HCV-positive HCC in the current study. The role of episomal form of HBV DNA requires further investigation of its involvement in the process of the development of HBsAg-negative, anti-HCV-positive HCC.  相似文献   
9.
The medicinal leech is one of the few parasitic invertebrates widely used in medicine and as a scientific model object. Because of a dramatic decline in its natural populations, it is subject to considerable conservation effort. Despite all attention, there is confusion regarding the taxonomic status of different morphological forms. The prevailing view is that all varieties of medicinal leech in Europe represent the same species, Hirudo medicinalis. However, the present study based on RAPD molecular markers demonstrates that a second European taxon, H. verbana, forms a distinct species. Phenetic clustering and principal coordinate analysis of eight populations revealed the same basic structure, reflecting taxonomic rather than geographic subdivision. Variation between species explained 60% of the total molecular variance (CT=0.60, P<0.001). Both taxa displayed a significant number of specific RAPD markers. Conversely, no specific fragment supporting the geographic association of both taxa was found. Since the stronghold of commercially exploited medicinal leech populations in southeastern Europe and Turkey belongs to H. verbana, most medicinal and scientific applications probably use this species, not H. medicinalis. Appropriate taxonomic correction of international conservation conventions and legislation is essential.  相似文献   
10.
Immunoglobulin A and G (IgA, IgG) serum concentrations were detected in children with nonallergic/intrinsic (36 children) or allergic/extrinsic asthma (43 children) and in age-matching control children (40 children). Asthmatic children with allergic asthma had lower IgA (1.36+/-0.54 g/L) and higher IgG (10.48+/-2.77 g/L) levels than the age-matching control children group (1.63+/-0.69 vs. 9.01+/-2.32 g/L). Children with nonallergic/intrinsic asthma had lower IgA (1.03+/-0.41 g/L) ( p = 0.004) and IgG (8.38+/-1.93 g/L) (p = 0.001) levels than the allergic/extrinsic asthma group (1.36+/-0.54 vs. 10.48+/-2.77 g/L). Low IgA levels were found in children with nonallergic/intrinsic asthma and high IgG levels were found in those children with allergic/extrinsic childhood asthma. The hypothesis is that the increased incidence of asthma in the population may be caused by a decrease in childhood infections (hygiene hypothesis). Frequent infections in early life boost the immune system, stimulating Th1-type response in young children and reducing the risk of atopic diseases. Our hypothesis is that low IgA (and/or IgG) levels in our patients might be responsible for infection development among those children with nonallergic/intrinsic asthma. These infections stimulate the normal development of immune system in young children, reducing risk of atopy, so that those children do not get allergic/extrinsic childhood asthma. Intrinsic childhood asthma=nonallergic (nonatopic) childhood asthma. Extrinsic childhood asthma=allergic (atopic) childhood asthma.  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