全文获取类型
收费全文 | 594篇 |
免费 | 25篇 |
国内免费 | 22篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 34篇 |
妇产科学 | 8篇 |
基础医学 | 66篇 |
口腔科学 | 10篇 |
临床医学 | 59篇 |
内科学 | 83篇 |
皮肤病学 | 7篇 |
神经病学 | 5篇 |
特种医学 | 196篇 |
外科学 | 42篇 |
综合类 | 4篇 |
预防医学 | 27篇 |
眼科学 | 10篇 |
药学 | 50篇 |
肿瘤学 | 39篇 |
出版年
2021年 | 6篇 |
2019年 | 4篇 |
2018年 | 6篇 |
2016年 | 2篇 |
2015年 | 5篇 |
2014年 | 2篇 |
2013年 | 19篇 |
2012年 | 12篇 |
2011年 | 8篇 |
2010年 | 15篇 |
2009年 | 16篇 |
2008年 | 10篇 |
2007年 | 28篇 |
2006年 | 17篇 |
2005年 | 16篇 |
2004年 | 9篇 |
2003年 | 8篇 |
2002年 | 2篇 |
2001年 | 11篇 |
2000年 | 7篇 |
1999年 | 3篇 |
1998年 | 33篇 |
1997年 | 44篇 |
1996年 | 25篇 |
1995年 | 27篇 |
1994年 | 19篇 |
1993年 | 15篇 |
1992年 | 9篇 |
1991年 | 13篇 |
1990年 | 11篇 |
1989年 | 21篇 |
1988年 | 28篇 |
1987年 | 20篇 |
1986年 | 20篇 |
1985年 | 22篇 |
1984年 | 11篇 |
1983年 | 8篇 |
1982年 | 17篇 |
1981年 | 9篇 |
1980年 | 16篇 |
1979年 | 8篇 |
1978年 | 7篇 |
1977年 | 9篇 |
1976年 | 15篇 |
1975年 | 6篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1971年 | 2篇 |
1969年 | 3篇 |
1968年 | 4篇 |
排序方式: 共有641条查询结果,搜索用时 31 毫秒
101.
输血是挽救创伤患者生命而普遍使用的治疗方法,但其又存在着明显和潜在的危险性。当今,经血液传播传染病和输血反应很少发生,但仍然存在。尽管在临床治疗中试图控制创伤患者休克的发展及损伤的严重度,但其输血后细菌感染、多脏器功能衰竭、死亡的发生率仍较高。 相似文献
102.
GTA Jombo EM Mbaawuaga AN Gyuse MNO Enenebeaku EE Okwori EJ Peters S Akpan F Odey EA Etukumana JT Akosu 《Asian Pacific journal of tropical medicine》2010,3(5):402-406
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
103.
Ronald Boellaard Mike J. O’Doherty Wolfgang A. Weber Felix M. Mottaghy Markus N. Lonsdale Sigrid G. Stroobants Wim J. G. Oyen Joerg Kotzerke Otto S. Hoekstra Jan Pruim Paul K. Marsden Klaus Tatsch Corneline J. Hoekstra Eric P. Visser Bertjan Arends Fred J. Verzijlbergen Josee M. Zijlstra Emile F. I. Comans Adriaan A. Lammertsma Anne M. Paans Antoon T. Willemsen Thomas Beyer Andreas Bockisch Cornelia Schaefer-Prokop Dominique Delbeke Richard P. Baum Arturo Chiti Bernd J. Krause 《European journal of nuclear medicine and molecular imaging》2010,37(1):181-200
The aim of this guideline is to provide a minimum standard for the acquisition and interpretation of PET and PET/CT scans with [18F]-fluorodeoxyglucose (FDG). This guideline will therefore address general information about [18F]-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET/CT) and is provided to help the physician and physicist to assist to carrying out, interpret, and document quantitative FDG PET/CT examinations, but will concentrate on the optimisation of diagnostic quality and quantitative information. 相似文献
104.
Marleen?J?NahuisEmail author Nienke?S?Weiss Fulco?van der Veen Ben?Willem?J?Mol Peter?G?Hompes Jur?Oosterhuis Nils?B?Lambalk Jesper?MJ?Smeenk Carolien?AM?Koks Ron?JT?van Golde Joop?SE?Laven Ben?J?Cohlen Kathrin?Fleischer Angelique?J?Goverde Marie?H?Gerards Nicole?F?Klijn Lizka?CM?Nekrui Ilse?AJ?van Rooij Diederik?A?Hoozemans Madelon?van Wely 《BMC women's health》2013,13(1):42
Background
Clomiphene citrate (CC) is first line treatment in women with World Health Organization (WHO) type II anovulation and polycystic ovary syndrome (PCOS). Whereas 60% to 85% of these women will ovulate on CC, only about one half will have conceived after six cycles. If women do not conceive, treatment can be continued with gonadotropins or intra-uterine insemination (IUI). At present, it is unclear for how many cycles ovulation induction with CC should be repeated, and when to switch to ovulation induction with gonadotropins and/or IUI.Methods/Design
We started a multicenter randomised controlled trial in the Netherlands comparing six cycles of CC plus intercourse or six cycles of gonadotrophins plus intercourse or six cycles of CC plus IUI or six cycles of gonadotrophins plus IUI.Women with WHO type II anovulation who ovulate but did not conceive after six ovulatory cycles of CC with a maximum of 150 mg daily for five days will be included.Our primary outcome is birth of a healthy child resulting from a pregnancy that was established in the first eight months after randomisation. Secondary outcomes are clinical pregnancy, miscarriage, multiple pregnancy and treatment costs. The analysis will be performed according to the intention to treat principle. Two comparisons will be made, one in which CC is compared to gonadotrophins and one in which the addition of IUI is compared to ovulation induction only. Assuming a live birth rate of 40% after CC, 55% after addition of IUI and 55% after ovulation induction with gonadotrophins, with an alpha of 5% and a power of 80%, we need to recruit 200 women per arm (800 women in total).An independent Data and Safety Monitoring Committee has criticized the data of the first 150 women and concluded that a sample size re-estimation should be performed after including 320 patients (i.e. 80 per arm).Discussion
The trial will provide evidence on the most effective, safest and most cost effective treatment in women with WHO type II anovulation who do not conceive after six ovulatory cycles with CC with a maximum of 150 mg daily for five days. This evidence could imply the need for changing our guidelines, which may cause a shift in large practice variation to evidence based primary treatment for these women.Trial registration number
Netherlands Trial register NTR1449105.
Snuff use and smoking among senior high school students: effects of a snuff sales ban 总被引:1,自引:0,他引:1
OBJECTIVES: The popularity of snuff especially among adolescents is rising. The association between long-term snuff use and oral cancer discovered in epidemiological studies has prompted a variety of preventive measures to be taken to reduce snuff use and prevent adoption of the habit. In this study, the effect of a recent (I March, 1995) snuff sales ban introduced in Finland was investigated. Further, the rates of smoking, snuff use, alcohol use and drug experimenting were investigated before the introduction of the ban to characterize the study population.
DESIGN AND SUBJECTS: Two questionnaire studies were carried out. The first was carried out 3 months prior to the ban in 1994 and the second 9 months after the ban in 1995 in a senior high school population in southwestern Finland. The participants were 793 students (aged 15–22 years) in the first survey and 545 students (aged 16–23) in the second. Associations between variables were analyzed using cross-tabulation and stepwise logistic regression. The effects of the ban were determined on the basis of direct questions in the second questionnaire relating to the snuff sales ban.
RESULTS: Snuff was used by 9% of the students participating in the first study. The results of the second questionnaire indicate that the implementation of the snuff sales ban reduced the rate of snuff use by 1% in the study population. The majority of the snuff users (76%) reported that they had maintained their snuff habit. Of those reporting that they were snuff users before implementation of the snuff sales ban, 12% had switched to smoking and 5% to drugs.
CONCLUSIONS: The results of the present study suggest that the snuff sales ban in this population with a high rate of snuff use had little effect on snuff use rates and may have some short-term negative consequences as some snuff users switch to other substitutes, such as smoking, with known adverse health effects. 相似文献
DESIGN AND SUBJECTS: Two questionnaire studies were carried out. The first was carried out 3 months prior to the ban in 1994 and the second 9 months after the ban in 1995 in a senior high school population in southwestern Finland. The participants were 793 students (aged 15–22 years) in the first survey and 545 students (aged 16–23) in the second. Associations between variables were analyzed using cross-tabulation and stepwise logistic regression. The effects of the ban were determined on the basis of direct questions in the second questionnaire relating to the snuff sales ban.
RESULTS: Snuff was used by 9% of the students participating in the first study. The results of the second questionnaire indicate that the implementation of the snuff sales ban reduced the rate of snuff use by 1% in the study population. The majority of the snuff users (76%) reported that they had maintained their snuff habit. Of those reporting that they were snuff users before implementation of the snuff sales ban, 12% had switched to smoking and 5% to drugs.
CONCLUSIONS: The results of the present study suggest that the snuff sales ban in this population with a high rate of snuff use had little effect on snuff use rates and may have some short-term negative consequences as some snuff users switch to other substitutes, such as smoking, with known adverse health effects. 相似文献
106.
The membrane mucin MUC4 is elevated in breast tumor lymph node metastases relative to matched primary tumors and confers aggressive properties to breast cancer cells 下载免费PDF全文
Heather C Workman Jamie K Miller Ellen Q Ingalla Rouminder P Kaur Diane I Yamamoto Laurel A Beckett Lawrence JT Young Robert D Cardiff Alexander D Borowsky Kermit L Carraway Colleen Sweeney Kermit L Carraway III 《Breast cancer research : BCR》2009,11(5):R70
Introduction
Previous studies indicate that overexpression of the membrane-associated mucin MUC4 is potently anti-adhesive to cultured tumor cells, and suppresses cellular apoptotic response to a variety of insults. Such observations raise the possibility that MUC4 expression could contribute to tumor progression or metastasis, but the potential involvement of MUC4 in breast cancer has not been rigorously assessed. The present study aimed to investigate the expression of the membrane mucin MUC4 in normal breast tissue, primary breast tumors and lymph node metastases, and to evaluate the role of MUC4 in promoting the malignant properties of breast tumor cells.Methods
MUC4 expression levels in patient-matched normal and tumor breast tissue was initially examined by immunoblotting lysates of fresh frozen tissue samples with a highly specific preparation of anti-MUC4 monoclonal antibody 1G8. Immunohistochemical analysis was then carried out using tissue microarrays encompassing patient-matched normal breast tissue and primary tumors, and patient-matched lymph node metastases and primary tumors. Finally, shRNA-mediated knockdown was employed to assess the contribution of MUC4 to the cellular growth and malignancy properties of JIMT-1 breast cancer cells.Results
Immunoblotting and immunohistochemistry revealed that MUC4 levels are suppressed in the majority (58%, p < 0.001) of primary tumors relative to patient-matched normal tissue. On the other hand, lymph node metastatic lesions from 37% (p < 0.05) of patients expressed higher MUC4 protein levels than patient-matched primary tumors. MUC4-positive tumor emboli were often found in lymphovascular spaces of lymph node metastatic lesions. shRNA-mediated MUC4 knockdown compromised the migration, proliferation and anoikis resistance of JIMT-1 cells, strongly suggesting that MUC4 expression actively contributes to cellular properties associated with breast tumor metastasis.Conclusions
Our observations suggest that after an initial loss of MUC4 levels during the transition of normal breast tissue to primary tumor, the re-establishment of elevated MUC4 levels confers an advantage to metastasizing breast tumor cells by promoting the acquisition of cellular properties associated with malignancy. 相似文献107.
Dysautonomia refers to a disease where the autonomic nervous system is dysfunctional. This may be a central control mechanism, as in genetically determined familial dysautonomia (Riley-Day Syndrome), or peripherally in the distribution of the sympathetic and parasympathetic systems. There are multiple reports of a number of different diseases associated with dysautonomia. The etiology of this association has never been explained. There are also multiple publications on dysautonomia associated with specific non-caloric nutritional deficiencies. Beriberi is the prototype of autonomic dysfunction. It is the best known nutritional deficiency disease caused by an imbalance between ingested calories and the vitamins required for their oxidation, particularly thiamin. Long thought to be abolished in modern medical thinking, there are occasional isolated reports of the full-blown disease in developed Western cultures. Apart from genetically and epigenetically determined disease, evidence is presented that marginal high calorie malnutrition, particularly with reference to simple carbohydrates, is responsible for widespread dysautonomia. The brain and heart are the organs that have a fast rate of oxidative metabolism and are affected early by any mechanism that reduces oxidative efficiency. It is hypothesized that this results in a chaotic state of the hypothalamic/autonomic/endocrine axis. Due to the lack of adequate automatic controls, this may be responsible in some cases for breakdown of organ systems through long-standing energy deficiency, thus leading eventually to organic disease. 相似文献
108.
BACKGROUND: Limited axillary skin excision and selective sweat gland removal from adjacent skin (Shelley's procedure) is currently rarely used for hyperhidrosis. OBJECTIVES: To determine whether this technique is a good way of permanently reducing axillary sweating. METHODS: This was a prospective, open, nonrandomized trial of the therapy, conducted in a university dermatology department. A small skin ellipse, parallel to the skin crease lines, was excised from the centre of the area of maximal sweating. The wound edges were undermined to the extent of maximal sweating and the skin reflected. Large visible sweat glands attached to the undersurface of the adjacent skin could be readily identified and were snipped off using scissors. We treated 15 axillae in eight patients with axillary hyperhidrosis. Sweat reduction was assessed by the patients who estimated the percentage reduction in sweating postoperatively. The scar appearance was graded by the surgeon. Haematoxylin and eosin-stained transverse sections of eight axillary skin ellipses from five subjects were examined histologically to establish the size, position and depth of the sweat gland tissue. RESULTS: All of the patients responded to treatment: mean sweat reduction was 65% (range 40-90%). Mean follow up was 1.3 years (range 0.1-6) and sweat reduction was maintained over this period. Histological material was available from five patients: sweat glands lay slightly deeper than hair follicles; glandular tissue occupied an average thickness of 3.5 mm in the 5-mm thick piece of skin. Apocrine gland lobules were more numerous and larger than eccrine gland lobules. Both gland types were in close apposition and did not occupy distinctly different depths within the skin. CONCLUSIONS: Local surgery using limited axillary skin excision and selective sweat gland removal remains one of the safest ways of permanently reducing axillary sweating. 相似文献
109.
OBJECTIVE
To assess, in the newborn, the efficacy of a standard taping treatment used in children for two selected congenital toe abnormalities (curly/varus/underlapping toes and overlapping toes), and compare the outcome with the available world literature.METHODS
All children referred by their family physician between January 2004 and January 2006 were included. The newborns were reviewed by one author (WGS) within 10 days of birth, assessed for severity, and the toes were taped in a standard manner if the abnormalities met the study criteria. After one and two months, the same author reviewed the children, and retaped the toes. The children’s toes were photographed before the taping and then after three months when the tape was removed permanently. After six months, the children, with their pictures, were sent to a second author (JTS), and were scored for the grade of severity and improvement using standard criteria.RESULTS
The world literature and standard textbooks indicate a 25% spontaneous improvement of these abnormalities. The recommendation is for surgical correction at a later date because intervention with taping has not shown success after the newborn period. No prior studies have been undertaken in the newborn. In the present study of 84 toes, the abnormality occurred in 2.8% of newborns, and 94% of the toes were improved or cured with no complications related to the technique.CONCLUSION
A simple, office-friendly technique of taping underlapping and overlapping toes in the newborn proved successful in 94% of the toes. 相似文献110.
John J Ah-Chan BMedSc MBChB Gordon Sanderson BScFBOA Brendan JT Vote MBBS Anthony CB Molteno FRACO 《Clinical & experimental ophthalmology》2001,29(6):416-425
Aim : To determine what New Zealand ophthalmologists, general practitioners and optometrists consider important ophthalmic topic areas requiring emphasis in the medical undergraduate curriculum. Method : A total of 793 questionnaires related to the content and teaching of undergraduate ophthalmology were sent to ophthalmologists, general practitioners and optometrists. Results were analysed separately for the three respondent groups and as a whole. Results : Four hundred and fourteen questionnaires were returned (52% return rate). Overall responses of the three participant groups were similar and agreed favourably with the current curriculum. The ability to measure visual acuity (97%) and pupillary reflexes (93%), perform ophthalmoscopy (92%), and assess visual fields (68%) were regarded as ‘important or essential’ by the majority of respondents. Only 53% of respondents consider the ability to diagnose chronic open angle glaucoma as important. The respondents stressed the importance of the diagnosis of predominantly anterior segment disease contrasting with the traditional bias towards the teaching of ophthalmoscopy and posterior segment disease. The majority of respondents stressed the importance of graduating medical students being able to treat bacterial and allergic conjunctivitis, styes, blepharitis, corneal abrasion, and corneal and conjunctival foreign bodies, areas present but not normally emphasized in current curricula. Conclusion : The findings of this study provided additional data to facilitate curriculum design and illustrated the value of an integrated problem‐based learning approach in ophthalmology undergraduate teaching. 相似文献