全文获取类型
收费全文 | 4232篇 |
免费 | 425篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 46篇 |
儿科学 | 255篇 |
妇产科学 | 117篇 |
基础医学 | 522篇 |
口腔科学 | 37篇 |
临床医学 | 536篇 |
内科学 | 671篇 |
皮肤病学 | 35篇 |
神经病学 | 310篇 |
特种医学 | 315篇 |
外科学 | 597篇 |
综合类 | 87篇 |
预防医学 | 500篇 |
眼科学 | 55篇 |
药学 | 260篇 |
中国医学 | 1篇 |
肿瘤学 | 318篇 |
出版年
2021年 | 52篇 |
2019年 | 47篇 |
2018年 | 48篇 |
2017年 | 48篇 |
2016年 | 51篇 |
2015年 | 55篇 |
2014年 | 81篇 |
2013年 | 114篇 |
2012年 | 132篇 |
2011年 | 182篇 |
2010年 | 87篇 |
2009年 | 125篇 |
2008年 | 184篇 |
2007年 | 231篇 |
2006年 | 215篇 |
2005年 | 190篇 |
2004年 | 185篇 |
2003年 | 148篇 |
2002年 | 134篇 |
2001年 | 139篇 |
2000年 | 168篇 |
1999年 | 136篇 |
1998年 | 56篇 |
1997年 | 41篇 |
1996年 | 32篇 |
1995年 | 50篇 |
1994年 | 39篇 |
1993年 | 38篇 |
1992年 | 107篇 |
1991年 | 111篇 |
1990年 | 124篇 |
1989年 | 118篇 |
1988年 | 89篇 |
1987年 | 95篇 |
1986年 | 95篇 |
1985年 | 97篇 |
1984年 | 59篇 |
1983年 | 48篇 |
1982年 | 33篇 |
1980年 | 38篇 |
1979年 | 54篇 |
1978年 | 43篇 |
1977年 | 41篇 |
1976年 | 39篇 |
1975年 | 36篇 |
1974年 | 52篇 |
1973年 | 31篇 |
1971年 | 28篇 |
1970年 | 29篇 |
1969年 | 25篇 |
排序方式: 共有4662条查询结果,搜索用时 0 毫秒
1.
The connective tissue of the knee is frequently injured by athletes, especially those involved in contact sports. It would be important in the prevention of injury as well as the strategy of physical fitness training to know whether the connective tissue is modified in response to athletic stress or training. The potential modification investigated was variability in the concentration of hydroxyproline, a post-translationally modified imino acid found principally in collagen protein. A correlation was sought between this variability and the leg strength parameters torque (expressed as ft-lbs), torque/body weight and work (expressed as ft-lbs). In a preliminary study of five subjects, no correlation was found between hydroxyproline concentration of the patellar tendon and any of the leg strength parameters. These results suggest that this modification of the collagen in connective tissue does not occur in response to athletic stress or training, but rather, for the small number of subjects investigated, appeared to be relatively constant across a range of leg strengths. 相似文献
2.
3.
HEAD CIRCUMFERENCE AND INTELLECTUAL PERFORMANCE OF PATIENTS WITH DUCHENNE MUSCULAR DYSTROPHY 总被引:3,自引:1,他引:2
R. E. Appleton K. Bushby D. Gardner-Medwin J. Welch P. J. Kelly 《Developmental medicine and child neurology》1991,33(10):884-890
The head circumferences of 64 patients with Duchenne muscular dystrophy were measured and found to be greater than those of a normal population. The patients had relative, and in 12 cases, absolute macrocephaly. 47 of the 64 patients underwent intelligence testing and were found to be significantly intellectually impaired, particularly in verbal and language skills. There was no correlation between head circumference or absolute macrocephaly and intellectual performance. The cause of macrocephaly in these patients is unknown and its relevance to the aetiology of intellectual impairment in Duchenne muscular dystrophy is not yet clear. 相似文献
4.
Patrick N Smith Jeffrey R Balzer Mustafa H Khan Rick A Davis Donald Crammond William C Welch Peter Gerszten Robert J Sclabassi James D Kang William F Donaldson 《The spine journal》2007,7(1):83-87
BACKGROUND CONTEXT: Intraoperative somatosensory evoked potential (SSEP) monitoring has been shown to reduce the incidence of new postoperative neurological deficits in scoliosis surgery. However, its usefulness during cervical spine surgery remains a subject of debate. PURPOSE: To determine the utility of intraoperative SSEP monitoring in a specific patient population (those with cervical radiculopathy in the absence of myelopathy) who underwent anterior cervical discectomy and fusion (ACDF) surgery. STUDY DESIGN: Retrospective review. PATIENT SAMPLE: A total of 1,039 nonmyelopathic patients who underwent single or multilevel ACDF surgery. The control group (462 patients) did not have intraoperative SSEP monitoring, whereas the monitored group (577 patients) had continuous intraoperative SSEP monitoring performed. OUTCOME MEASURE: A new postoperative neurological deficit. METHODS: SSEP tracings were reviewed for all 577 patients in the monitored group and all significant signal changes were noted. Medical records were reviewed for all 1,039 patients to determine if any new neurological deficits developed in the immediate postoperative period. RESULTS: None of the patients in the control group had any new postoperative neurological deficits. In the monitored group there were six instances of transient SSEP changes (1 due to suspected carotid artery compression; 5 thought to be due to transient hypotension) which resolved with the appropriate intraoperative intervention (repositioning of retractors; raising the arterial blood pressure). Upon waking up from anesthesia, one patient in the monitored group had a new neurological deficit (partial central cord syndrome) despite normal intraoperative SSEP signals. CONCLUSIONS: ACDF appears to be a safe surgical procedure with a low incidence of iatrogenic neurological injury. Transient SSEP signal changes, which improved with intraoperative interventions, were not associated with new postoperative neurological deficits. An intraoperative neurological deficit is possible despite normal SSEP signals. 相似文献
5.
Primary squamous cell carcinoma is an extremely rare tumour of the thyroid gland. A case of an elderly lady who was diagnosed to have primary squamous cell carcinoma of the thyroid gland is presented and the role of radiotherapy is discussed. 相似文献
6.
David G Hicks Brian J Yoder Sarah Short Shannon Tarr Nichole Prescott Joseph P Crowe Andrea E Dawson G Thomas Budd Steven Sizemore Muzaffer Cicek Toni K Choueiri Raymond R Tubbs Daniel Gaile Norma Nowak Mary Ann Accavitti-Loper Andra R Frost Danny R Welch Graham Casey 《Clinical cancer research》2006,12(22):6702-6708
PURPOSE: This study aims to determine the effect of loss of breast cancer metastasis suppressor 1 (BRMS1) protein expression on disease-free survival in breast cancer patients stratified by estrogen receptor (ER), progesterone receptor (PR), or HER2 status, and to determine whether loss of BRMS1 protein expression correlated with genomic copy number changes. EXPERIMENTAL DESIGN: A tissue microarray immunohistochemical analysis was done on tumors of 238 newly diagnosed breast cancer patients who underwent surgery at the Cleveland Clinic between January 1, 1995 and December 31, 1996, and a comparison was made with 5-year clinical follow-up data. Genomic copy number changes were determined by array-based comparative genomic hybridization in 47 breast cancer cases from this population and compared with BRMS1 staining. RESULTS: BRMS1 protein expression was lost in nearly 25% of cases. Patients with tumors that were PR negative (P=0.006) or HER2 positive (P=0.039) and <50 years old at diagnosis (P=0.02) were more likely to be BRMS1 negative. No overall correlation between BRMS1 staining and disease-free survival was observed. A significant correlation, however, was seen between loss of BRMS1 protein expression and reduced disease-free survival when stratified by either loss of ER (P=0.008) or PR (P=0.029) or HER2 overexpression (P=0.026). Overall, there was poor correlation between BRMS1 protein staining and copy number status. CONCLUSIONS: These data suggest a mechanistic relationship between BRMS1 expression, hormone receptor status, and HER2 growth factor. BRMS1 staining could potentially be used in patient stratification in conjunction with other prognostic markers. Further, mechanisms other than genomic deletion account for loss of BRMS1 gene expression in breast tumors. 相似文献
7.
8.
9.
10.
Immunodiagnosis of Entamoeba histolytica and Ascaris lumbricoides infections in Caucasian and aboriginal Australians 总被引:1,自引:0,他引:1
J S Welch C Dobson S Chopra 《Transactions of the Royal Society of Tropical Medicine and Hygiene》1986,80(2):240-247
The immunodiagnostic efficiency of an indirect immunofluorescence test (IFAT) and in vitro lymphocyte proliferative responsiveness (cell mediated immunity test, CMIT) used to measure the immunological responses of individuals with known natural Entamoeba histolytica and Ascaris lumbricoides infections, was studied under survey conditions. E. histolytica was common among Aborigines from Cherbourg, Kowanyama and Central Australia, but it was not found in Brisbane Caucasians. The protozoan was selected for the study because it was prevalent and purified antigen was commercially available. Immunodiagnosis for A. lumbricoides was made using an antigen prepared by affinity chromatography. Diagnosis based on frequency distribution of immunological data gave valid assessment of the number of infected individuals in each population studied. 相似文献