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   1293903篇
  免费   99750篇
  国内免费   2022篇
耳鼻咽喉   18692篇
儿科学   44974篇
妇产科学   35439篇
基础医学   184379篇
口腔科学   34074篇
临床医学   113277篇
内科学   261054篇
皮肤病学   28184篇
神经病学   101273篇
特种医学   51742篇
外国民族医学   660篇
外科学   198544篇
综合类   27450篇
现状与发展   1篇
一般理论   394篇
预防医学   97426篇
眼科学   28250篇
药学   95891篇
  2篇
中国医学   2493篇
肿瘤学   71476篇
  2018年   13386篇
  2017年   10166篇
  2016年   11103篇
  2015年   12588篇
  2014年   17513篇
  2013年   26715篇
  2012年   36787篇
  2011年   38859篇
  2010年   23218篇
  2009年   22158篇
  2008年   37294篇
  2007年   39976篇
  2006年   40196篇
  2005年   39142篇
  2004年   38228篇
  2003年   37047篇
  2002年   36338篇
  2001年   64474篇
  2000年   66913篇
  1999年   56845篇
  1998年   15318篇
  1997年   13944篇
  1996年   14374篇
  1995年   13598篇
  1994年   12906篇
  1993年   11907篇
  1992年   44894篇
  1991年   43789篇
  1990年   42533篇
  1989年   40387篇
  1988年   37172篇
  1987年   36482篇
  1986年   33874篇
  1985年   32545篇
  1984年   24337篇
  1983年   20448篇
  1982年   11860篇
  1981年   10826篇
  1980年   9634篇
  1979年   21552篇
  1978年   14992篇
  1977年   12684篇
  1976年   11823篇
  1975年   12752篇
  1974年   14816篇
  1973年   14291篇
  1972年   13081篇
  1971年   11861篇
  1970年   11186篇
  1969年   10147篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Inguinal hernia is a known complication after radical retropubic prostatectomy (RRP). We have investigated whether other types of lower midline incision surgery in males increase the risk of inguinal hernia. Male patients operated with open prostatectomy for benign prostate hyperplasia (n = 95), pelvic lymph node dissection for staging of prostate cancer (n = 88), or cystectomy for bladder cancer (n = 76) were identified and were sent questionnaires in which they were asked about postoperative inguinal hernia morbidity. Two-hundred and seventy-one men operated with RRP had previously received a similar questionnaire. The answers were compared with those from a control group of 953 men who had not undergone surgery. Annual attributional hernia morbidity and Kaplan–Meier hernia-free survival were calculated. The cumulative incidence of post-operative inguinal hernia and annual attributional hernia morbidity after the respective surgical procedures were clearly higher during the early years post-operation than for nonoperated patients. Inguinal hernia is a common postoperative complication in males after all the lower midline incision surgery investigated.  相似文献   
992.
The co-existence of fungal elements in allergic nasal Polyposis, has given rise to a distinct clinical entity known as ‘Allergic fungal sinusitis ’ (AF’S). Many a time, these fungal elements may not be diagnosed pre-operatively by routine diagnostic nasal endoscopy or CT scan of paranasal sinuses, due to the florid presentation of nasal polyps, which usually obscure the underlying fungal pathology. The diagnosis is often made intra-operatively. The post-operative confirmation of AFS is by histopathology, fungal smear, fungal culture, allergic murin study and fungal specific IgE titres. We report a series often such cases done in our institution, which highlight that AFS should be considered as a differential diagnosis in Sinonasal Polyposis cases, for their effective management.  相似文献   
993.
Exercise advice is a well established component of the conservative management of intermittent claudication. Supervised programmes of exercise remain relatively uncommon and are provided mainly in secondary care. This review outlines the evidence for the effectiveness of different exercise regimens and the relative benefits of exercise therapy, where comparisons have been made with medical therapy, angioplasty and surgery.  相似文献   
994.
Hepatitis is a rare complication of herpes simplex virus (HSV), often leading to acute liver failure (ALF), liver transplantation (LT), and/or death. Our aim was to identify variables associated with either survival or progression (death/LT), based on an analysis of cases in the literature and our institution. A total of 137 cases (132 literature, 5 institutional) of HSV hepatitis were identified. The main features at clinical presentation were fever (98%), coagulopathy (84%), and encephalopathy (80%). Rash was seen in less than half of patients. Most cases (58%) were first diagnosed at autopsy and the diagnosis was suspected clinically prior to tissue confirmation in only 23%. Overall, 74% of cases progressed to death or LT, with 51% in acyclovir-treated patients as compared to 88% in the untreated subjects (P=0.03). Variables on presentation associated with death or need for LT compared to spontaneous survival: male gender, age>40 yr, immunocompromised state, ALT>5,000 U/L, platelet count<75x10(3)/L, coagulopathy, encephalopathy, and absence of antiviral therapy. In conclusion, HSV hepatitis has a high mortality and is often clinically unsuspected. Patients who are male, older, immunocompromised, and/or presenting with significant liver dysfunction are more likely to progress to death and should thus be evaluated for LT early. Based on the frequent delay in HSV diagnosis, low risk-benefit ratio, and significantly improved outcomes, empiric acyclovir therapy for patients presenting with ALF of unknown etiology is recommended until HSV hepatitis is excluded.  相似文献   
995.
996.
Fractures of the calcaneus generally occur in the event of high-energy trauma, resulting in complex, three-dimensionally oriented fracture patterns. Surgical management is generally indicated for displaced intra-articular fractures, which allows restoration of calcaneal height, width and overall morphology, in addition to the posterior facet articular surface where possible, and allows for a late in situ arthrodesis as a means of salvage in the event of posttraumatic arthritis. What follows is a brief discussion of our preferred methods in the diagnosis and management of calcaneal fractures.  相似文献   
997.
&#;zkir  S.  Droste  P.  Echtermeyer  V. 《Trauma und Berufskrankheit》2007,9(3):S351-S358
The aims in implantation of an artificial replacement hip joint should be lasting fixation and pain-free functioning of the elements of the prosthesis in the bone and minimal friction between the articulating parts. Despite improvements in bone cement and in cementing techniques, the question of whether cemented or cement-free hip replacement systems give better results in the long term is still the subject of controversy. The basics of cemented and cement-free implantation of prostheses, of the surgical techniques and of the corresponding results and complications are presented. Despite all the advantages of cement-free implantation over cemented implantation of prostheses, while the former yield good results in the short term, long-term results with a follow-up period of over 10 years are available for only a limited number of cement-free implants. Therefore, until long-term (15-year) results for the cement-free prosthetic systems currently on the market are available, cemented anchorage as practised since the introduction and application of the second-generation cementing techniques with the reduction of the risk of revision surgery by approximately 20% at present should be regarded as standard despite the more demanding implantation process.  相似文献   
998.
999.
Deceased donor factors associated with poor graft outcome are well known, but how often these factors lead to livers left untransplanted is poorly defined. A nested, case-control study was conducted using the United Network for Organ Sharing (UNOS) database from 1987 to 2005. Only those donating >/=1 solid organ were included. Primary outcome was livers not transplanted (LNT, cases) versus transplanted (LT, controls). Primary variables for multivariate analysis were donor age and obesity. Covariates included donation after cardiac death (DCD), cerebral vascular accident death, viral serologies, cancer, ALT and bilirubin. There were 23 373 (26%) LNT's from 91 362 donors who donated at least one organ. Percent LNT fell over time (1987-1990: 48%; 1991-1995: 29%; 1996-2000: 21%; 2000-2005: 16%; p < 0.01). Increased age (odds ratio: 4.2, 95% confidence interval 3.6-4.9, p < 0.01) and obesity (2.1, 1.9-2.3, p < 0.01) were significantly associated with LNT across all time periods. Other significant factors included DCD and elevated ALT. For 2001-2005, population attributable risk indicate that age >40, abnormal ALT and obesity account for 32.6%, 25.3% and 9.2% of untransplanted livers, respectively. Use of expanded criteria livers has pushed LNT lower in spite of an aging and heavier donor population. Nevertheless, age and obesity still account for a significant portion of untransplanted livers.  相似文献   
1000.
AIM: This prospective, split mouth control study was planned to clinically evaluate shown short-term caries protection of glass ionomer cement on tooth enamel placed in contact to it, as a result of fluoride release. STUDY DESIGN: The sample consisted of 83 children, aged 4-7 years, visiting a private practice during the years 1999 and 2000. All subjects met the following criteria: a Class II restoration was needed to a maxillary or mandibular primary molar on both sides of the mouth, the adjacent molars being radiographically diagnosed as sound or with caries in the relative proximal enamel only. METHODS: A resin modified glass ionomer restoration (Vitremer, 3M) was placed at the test side chosen by chance, while an amalgam or composite restoration was placed at the control side. Lesion initiation or progression adjacent to each restoration was categorized in 5 stages radiographically. STATISTICS: The non-parametric Marginal Homogeneity test for paired observations was used. RESULTS: Differences between test and control were not statistically significant (p>0.1). Two years after restorations were placed bitewings were taken from 36 children (41 pairs of restorations). Uncontrolled brushing with fluoride dentifrice was reported. Mean fluoride treatments performed were 2.2, initial visit included. Lesion progression was: 14 pairs--no progression in either side; 9 pairs--equal progression by 1 stage in both sides; 9 pairs--progression by 1 stage at test side, no progression at control side; 6 pairs--progression by 1 stage at control side, no progression at test side; 3 pairs--various other combinations of scores. CONCLUSIONS: Under these clinical conditions, fluoride release from Class II Vitremer restorations did not affect the rate of caries progression at the adjacent enamel of proximal primary teeth.  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