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   40171篇
  免费   2093篇
  国内免费   142篇
耳鼻咽喉   528篇
儿科学   2571篇
妇产科学   698篇
基础医学   4772篇
口腔科学   1115篇
临床医学   2903篇
内科学   7193篇
皮肤病学   1119篇
神经病学   2385篇
特种医学   1198篇
外科学   6067篇
综合类   1282篇
一般理论   17篇
预防医学   2036篇
眼科学   1490篇
药学   4017篇
  1篇
中国医学   353篇
肿瘤学   2661篇
  2023年   338篇
  2022年   978篇
  2021年   1620篇
  2020年   890篇
  2019年   985篇
  2018年   1389篇
  2017年   1010篇
  2016年   1344篇
  2015年   1345篇
  2014年   1990篇
  2013年   2243篇
  2012年   3168篇
  2011年   3075篇
  2010年   1840篇
  2009年   1453篇
  2008年   2072篇
  2007年   2089篇
  2006年   1909篇
  2005年   1686篇
  2004年   1569篇
  2003年   1318篇
  2002年   1128篇
  2001年   773篇
  2000年   706篇
  1999年   591篇
  1998年   264篇
  1997年   213篇
  1996年   218篇
  1995年   184篇
  1994年   155篇
  1993年   130篇
  1992年   349篇
  1991年   337篇
  1990年   359篇
  1989年   330篇
  1988年   285篇
  1987年   241篇
  1986年   234篇
  1985年   228篇
  1984年   174篇
  1983年   122篇
  1982年   68篇
  1981年   75篇
  1980年   69篇
  1979年   109篇
  1978年   71篇
  1977年   87篇
  1976年   65篇
  1973年   62篇
  1971年   60篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
The authors report a 50-year-old man with progressive left hemispheric atrophy, cognitive decline, infrequent seizures, and spells suggestive of complicated migraine. They discuss the association between migraine and cerebral hemiatrophy and suggest that the spectrum of acquired cerebral hemiatrophy may be broader than what has been commonly recognized.  相似文献   
82.
83.
Despite the common occurrence of pleomorphic adenoma of major salivary glands, intranasal pleomorphic adenoma are rare. We present a ease of pleomorphic adenoma of the nasal septum along with a brief review of literature. The histological nature of this lesion in comparison to other salivary gland tumours and the importance of an accurate diagnosis has been stressed.  相似文献   
84.
BACKGROUND: The advantage of 4-field radiation to the pelvis is that the use of lateral portals spares a portion of the small bowel anteriorly and rectum posteriorly. The standard lateral portals defined in textbooks are not always adequate especially in advanced cancer cervix. METHODS: An analysis was done to determine adequacy of margins of standard lateral pelvic portals with CECT defined tumor volumes. The study included 40 patients of FIGO stage IIB and IIIB treated definitively for cancer cervix between 1998 and 2000. An inadequate margin was defined if the cervical growth and uterus were not encompassed by the 95% isodose. RESULTS: An inadequate posterior margin was common with bulky disease (P = 0.06) and with retroverted uterus (P = 0.08). Menopausal status, FIGO stage, associated myoma, and age were of no apparent prognostic significance. Bulk retained significant on multivariate analysis. An inadequate anterior margin was common in premenopausal (P = 0.01); anteverted uterus (P = 0.02); associated myoma (P = 0.01); and younger patients (P = 0.03). It was not influenced by bulk or stage. Menopausal status and associated myoma retained significant on multivariate analysis. CONCLUSION: Without the knowledge of precise tumor volume, the 4-field technique with standard portals is potentially risky as it may under dose the tumor through lateral portals and the standard AP/ PA portals are a safer option.  相似文献   
85.
OBJECTIVES: To evaluate the efficacy of oral lycopene therapy in patients with oral submucous fibrosis and to compare these effects with a placebo. STUDY DESIGN: Fifty-eight patients with oral submucous fibrosis formed the population for the study and were randomly divided into 3 groups, evaluated weekly over a 2-month period. Patients of group A (n = 21) received 16 mg of lycopene, those of group B (n = 19) received 16 mg of lycopene along with biweekly intralesional steroid injections, and those of group C (n = 18) were given a placebo. Paired and unpaired t tests were used for statistical evaluation. RESULTS: Mouth-opening values for the patients showed an average increase of 3.4 mm, 4.6 mm, and 0.0 mm for patients in groups A, B, and C, respectively. These values were statistically found to be highly significant. CONCLUSIONS: The observed effects suggest that lycopene can and should be used as a first line of therapy in the initial management of oral submucous fibrosis.  相似文献   
86.
87.
88.
A 48 year old male presented with a one and a half year history of a progressively increasing, asymptomatic lump in the left hypochondrium and no history of hematuria. His general physical examination was unremarkable, and an abdominal examination revealed a large, firm, irregular and tender mass in the left hypochondrium extending into the lumbar region. Chest X-ray was normal. An intravenous urogram revealed a normally functioning right kidney with non-visualization of the left kidney. CT-scan of the abdomen revealed a large, mixed attenuating mass replacing the left kidney. At laparotomy, a large, fleshy, well-encapsulated tumor was found in the left kidney with no surrounding infiltration and a left radical nephrectomy was performed. Microscopic examination revealed a poorly differentiated tumor comprised of small round cells with focal areas of abortive embryonal tubular and glomerular differentiation suggestive of Wilms' tumor. The patient was advised chemotherapy and radiotherapy but he absconded and was lost to follow-up.  相似文献   
89.
Pulmonary functions were measured in 15 patients with severe chronic anaemia (haemoglobin level < 5 g/dl). The measurements were repeated after correction of anaemia (Hb > 10 g/dl). Twenty age and sex matched, asymptomatic, non-smoker subjects served as controls. There was 80-100% improvement in various lung functions after correction of anaemia. Effort dependent parameters, viz FVC, ERV, IC, MVV were low in anaemic patients which improved with the rise of haemoglobin. The TLCO, DM, VC, KCO were not significantly influenced during anaemic state. FEV1, PEFR, RV/TLC were essentially normal. We conclude that the observed changes produced in lung functions during anaemic state are fully reversible after its correction.  相似文献   
90.
Protein A is an immunostimulating glycoprotein obtained from Staphylococcus aureus Cowan I. Its antitumour activity is proven in various tumour models. Its ability to provide protection against tumour initiation by the chemical carcinogen 7,12-dimethylbenzanthracene (DMBA) has been investigated in the present study using a mouse skin model of two-stage carcinogenesis. Protein A was administered intraperitoneally (1 microgram/animal 20 g body wt.) twice a week for 2 weeks, prior to initiation by DMBA. The promotion was performed by twice weekly applications of 12-O-tetradecanoyl phorbol-13-acetate (TPA) (3 or 5 micrograms/animal in 100 microliters acetone). Protein A provided significant protection to animals from DMBA-induced tumour initiation as was observed by the decrease in cumulative number of tumours, percent of animals developing tumours, number of tumours per animal and rate of tumour growth. Our data indicate that protein A has anticarcinogenic properties.  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