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   1355490篇
  免费   101650篇
  国内免费   4319篇
耳鼻咽喉   17005篇
儿科学   44385篇
妇产科学   36906篇
基础医学   200634篇
口腔科学   36405篇
临床医学   132006篇
内科学   261899篇
皮肤病学   26690篇
神经病学   113539篇
特种医学   48914篇
外国民族医学   366篇
外科学   186540篇
综合类   29097篇
现状与发展   1篇
一般理论   497篇
预防医学   116462篇
眼科学   29332篇
药学   100021篇
  8篇
中国医学   3180篇
肿瘤学   77572篇
  2021年   11334篇
  2019年   12043篇
  2018年   16780篇
  2017年   12663篇
  2016年   13618篇
  2015年   15672篇
  2014年   21459篇
  2013年   32904篇
  2012年   45406篇
  2011年   48135篇
  2010年   27748篇
  2009年   25469篇
  2008年   43741篇
  2007年   46145篇
  2006年   46222篇
  2005年   44602篇
  2004年   42458篇
  2003年   40347篇
  2002年   39008篇
  2001年   61254篇
  2000年   62942篇
  1999年   52607篇
  1998年   14782篇
  1997年   13431篇
  1996年   13278篇
  1995年   12618篇
  1994年   11799篇
  1993年   11043篇
  1992年   41866篇
  1991年   41064篇
  1990年   39730篇
  1989年   37615篇
  1988年   34848篇
  1987年   33924篇
  1986年   32347篇
  1985年   30882篇
  1984年   23246篇
  1983年   19768篇
  1982年   11869篇
  1979年   20959篇
  1978年   14963篇
  1977年   12176篇
  1976年   11985篇
  1975年   12240篇
  1974年   14932篇
  1973年   14622篇
  1972年   13480篇
  1971年   12538篇
  1970年   11583篇
  1969年   10499篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
L. Klimek  C. Thorn  O. Pfaar 《HNO》2004,63(9):92
  相似文献   
992.
The main objective of this study was to examine the psychosocial stress model developed by Taylor and Aspinwall with emotional exhaustion as the outcome variable. Respondents, 409 men and 346 women, who had a paid job for at least 20 hours per week, completed questionnaires concerning demographic variables, personality, temperament, work pressure, workload, perceived social support, appraisal, coping, and emotional exhaustion. Structural equation analyses provided only partial support for the validity of the model. First, on theoretical and statistical grounds, one more path linking external resources to social support was added. Second, contrary to expectations, coping styles did not predict emotional exhaustion. To conclude, when coping is measured retrospectively, it does not add to our understanding of emotional exhaustion. It is suggested that future studies should be longitudinal and include objective measures of stressors and psychosocial health outcomes in addition to self‐reports. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   
993.
Background It is estimated that skin cancers cost $33 million per annum to the New Zealand healthcare system. Basal cell carcinoma and squamous cell carcinoma are the commonest types of non melanoma skin cancers (NMSCs). Anecdotal evidence indicates that there has been a doubling in the incidence of NMSCs in New Zealand over the last decade. Because of the high incidence mandatory reporting of NMSCs to the National Cancer Registry is not required. This lack of accurate data has led to poor health care policies and strategies including funding and workforce planning. Aims The aims of this study are to (1) present the latest statistics on NMSCs in New Zealand, including the incidence across different regions over the last decade, patient demographics, anatomic distribution of NMSCs, incidence and sites of metastasis, and disease‐specific survival; to (2) the histopathology of NMSCs, including surgical margins, histologic grade, and perineural, lymphatic, and vascular invasion; and (3) the relative role of different faculties treating NMSCs. Method This project has been approved by the multi‐centre ethics committee. A retrospective review was conducted from patients’ histology records from public and private pathology laboratories within defined catchment areas. Criterion for analysis is a confirmed diagnosis of NMSC treated surgically. A Microsoft Access database is created that will facilitate subsequent data retrieval and analysis. Results and Conclusion It is hoped that this up‐to‐date data will form the framework for the development of sound and sustainable healthcare policies of management of NMSCs including management strategies and workforce planning, and research direction on this common disease.  相似文献   
994.
Efficacy and safety of mycophenolate mofetil (MMF) may be optimized with individualized doses based on therapeutic monitoring of its active metabolite, mycophenolic acid (MPA). In this 12-month study, 137 renal allograft recipients from 11 French centers receiving basiliximab, cyclosporine A, MMF and corticosteroids were randomized to receive either concentration-controlled doses or fixed-dose MMF. A novel Bayesian estimator of MPA AUC based on three-point sampling was used to individualize doses on posttransplant days 7 and 14 and months 1, 3 and 6. The primary endpoint was treatment failure (death, graft loss, acute rejection and MMF discontinuation). Data from 65 patients/group were analyzed. At month 12, the concentration-controlled group had fewer treatment failures (p = 0.03) and acute rejection episodes (p = 0.01) with no differences in adverse event frequency. The MMF dose was higher in the concentration-controlled group at day 14 (p < 0.0001), month 1 (p < 0.0001) and month 3 (p < 0.01), as were median AUCs on day 14 (33.7 vs. 27.1 mg*h/L; p = 0.0001) and at month 1 (45.0 vs. 30.9 mg*h/L; p < 0.0001). Therapeutic MPA monitoring using a limited sampling strategy can reduce the risk of treatment failure and acute rejection in renal allograft recipients 12 months posttransplant with no increase in adverse events.  相似文献   
995.
OBJECTIVES: To present a single centers' 7-year experience in the endovascular treatment of acute traumatic lesions of the descending thoracic aorta (ATL of the DTA). MATERIALS & METHODS: Between March 1999 and December 2006, 34 consecutive acute traumatic lesions of the descending aorta (23 men, mean age 44 years) were treated endovascularly. Stentgrafts used were TAG Excluder, Zenith TX2 and Talent. In 23 patients the Left Subclavian Artery (LSA) was covered. Mean procedural duration was 20 to 75 minutes. RESULTS: Exclusion of the rupture site was achieved in all cases with no conversion to open surgery. Overall 30-day mortality was 8.8%. Two patients died on post operative day (pod) 1 and one on pod 22 from cranial injuries. No death or neurological deficit related to the endovascular treatment was reported. Four type I endoleaks required treatment either by balloon reexpansion (n=2) or by additional stentgraft implantation (n=2). In two patients the stentgraft collapsed totally several days postoperatively. Two patients required secondary surgical procedures (iliac access complication and revascularisation of the left subclavian artery n=1). The average follow-up was 43.8 months (1-93 months). No stentgraft related abnormality has been subsequently documented. CONCLUSIONS: The endovascular treatment of ATL of the DTA may offer the best means of therapy in a polytrauma patient.  相似文献   
996.
Presentations of acute appendicitis represent an ongoing challenge to surgeons. This case of retrocaecal perforated appendicitis presented clinically as a right lumbar abscess, with the concomitant new diagnosis of type 2 diabetes mellitus in a 66-year-old male. This case emphasises the importance of an abdominal CT scan in any patient presenting with unusual sepsis near the abdomen.  相似文献   
997.
Heart transplantation (HTx) is a useful therapy for end‐stage Chaga? cardiomyopathy; however, Chagas reactivation remains a mayor complication. Parasitological methods offer poor diagnostic sensitivity, and use of more sensitive tools such as the Polymerase chain reaction (PCR) is usually necessary. In the present study, reactivation incidence and PCR usefulness for early reactivation diagnosis, as well as for treatment response evaluation during follow‐up, were analyzed using Strout parasite detection test, in 10 of 222 consecutive HTx patients suffering Chagas cardiomyopathy. PCR strategies targeted to minicircle sequences (kDNA, detection limit 1 parasite/ 10 mL blood) and miniexon genes (SL‐DNA, 200 parasite/10 mL) were performed to compare parasite burdens between samples. No patients received prophylactic antiprotozoal therapy (benznidazole). Five patients (50%) exhibited clinical reactivation within a mean period of 71.6 days; positive Strout results were observed in most cases presenting clinical manifestations. kDNA‐PCR was positive 38–85 days before reactivation, whereas SLDNA‐PCR became positive only 7–21 days later, revealing post‐HTx parasitic load enhancement present prior to clinical reactivation development. Reactivations were successfully treated with benznidazole and generated negative PCR results. Results observed in this study indicate the value of PCR testing for an early diagnosis of Chagas reactivation as well as for monitoring treatment efficacy.  相似文献   
998.
Chronic, recurrent, multifocal osteomyelitis (CRMO) is an obscure disease of bone, occurring in children. It appears to be an inflammatory condition with no obvious microbiological cause. Current treatments of antibiotics and anti-inflammatory medication appear to have limited success. This case report looks at two separate cases of CRMO where partial resection of the affected bone—the clavicle—leads to complete resolution of symptoms and regrowth of the excised bone.  相似文献   
999.
Interleukin (IL)-13 plays a central role in asthma pathogenesis by binding to the IL-13 receptor, which is a heterodimer composed of the IL-13 receptor alpha1 subunit (IL-13Ralpha1) and IL-4Ralpha. The genetic diversity at the IL-13Ralpha1 gene (IL13RA1) locus on chromosome Xq24 was characterised and the association of identified polymorphisms with asthma and atopy phenotypes examined. The promoter and coding region of IL13RA1 were screened for common genetic variants, and polymorphisms found were genotyped in a large cohort of 341 asthmatic Caucasian families (each containing at least two asthmatic siblings) and 182 nonasthmatic control subjects. Genetic association was determined using case-control and transmission disequilibrium test analyses. Two common polymorphisms were identified, a newly found thymidine (T) to guanine (G) transition of nucleotide -281 (-281T>G) single nucleotide polymorphism in the IL13RA1 promoter and the previously described 1365A>G variant in the IL13RA1 proximal 3' untranslated region. No significant association of either -281T>G or 1365A>G with risk of asthma or atopy phenotypes was found, apart from a suggestive association between the IL13RA1 -281T/1365A haplotype and raised total serum immunoglobulin E levels in adult female asthmatics. These findings indicate that the interleukin-13 receptor alpha1 subunit gene -281T>G and 1365A>G polymorphisms do not contribute to asthma susceptibility or severity, although the interleukin-13 receptor alpha1 subunit gene locus might be involved in the control of immunoglobulin E production.  相似文献   
1000.
Pulmonary hypertension (PH) may complicate idiopathic pulmonary fibrosis (IPF) but the prevalence of PH in IPF remains undefined. The present authors sought to describe the prevalence of PH in IPF. The lung transplant registry for the USA (January 1995 to June 2004) was analysed and IPF patients who had undergone right heart catheterisation (RHC) were identified. PH was defined as a mean pulmonary arterial pressure ((Ppa)) > or =25 mmHg and severe PH as a (Ppa) >40 mmHg. Independent factors associated with PH were determined. Of the 3,457 persons listed, 2,525 (73.0%) had undergone RHC. PH affected 46.1% of subjects; approximately 9% had severe PH. Variables independently associated with mild-to-moderate PH were as follows: need for oxygen, pulmonary capillary wedge pressure (P(pcw)) and forced expiratory volume in one second (FEV(1)). Independent factors related to severe PH included the following: carbon dioxide tension, age, FEV(1), P(pcw), need for oxygen and ethnicity. A sensitivity analysis in subjects with P(pcw) <15 mmHg did not appreciably alter the present findings. Pulmonary hypertension is common in idiopathic pulmonary fibrosis patients awaiting lung transplant, but the elevations in mean pulmonary arterial pressure are moderate. Lung volumes alone do not explain the pulmonary hypertension. Given the prevalence of pulmonary hypertension and its relationship with surrogate markers for quality of life (e.g. activities of daily living), future trials of therapies for this may be warranted.  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