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   31098篇
  免费   2654篇
  国内免费   80篇
耳鼻咽喉   380篇
儿科学   851篇
妇产科学   541篇
基础医学   4124篇
口腔科学   423篇
临床医学   3308篇
内科学   6324篇
皮肤病学   431篇
神经病学   2726篇
特种医学   1010篇
外国民族医学   3篇
外科学   4727篇
综合类   600篇
一般理论   25篇
预防医学   2996篇
眼科学   951篇
药学   2188篇
中国医学   34篇
肿瘤学   2190篇
  2023年   236篇
  2022年   367篇
  2021年   895篇
  2020年   533篇
  2019年   844篇
  2018年   913篇
  2017年   642篇
  2016年   699篇
  2015年   787篇
  2014年   1105篇
  2013年   1463篇
  2012年   2183篇
  2011年   2200篇
  2010年   1129篇
  2009年   1061篇
  2008年   1674篇
  2007年   1807篇
  2006年   1676篇
  2005年   1657篇
  2004年   1555篇
  2003年   1333篇
  2002年   1236篇
  2001年   481篇
  2000年   489篇
  1999年   513篇
  1998年   335篇
  1997年   248篇
  1996年   255篇
  1995年   220篇
  1994年   190篇
  1993年   170篇
  1992年   321篇
  1991年   321篇
  1990年   308篇
  1989年   297篇
  1988年   270篇
  1987年   251篇
  1986年   282篇
  1985年   239篇
  1984年   212篇
  1983年   169篇
  1982年   162篇
  1981年   126篇
  1980年   126篇
  1979年   199篇
  1978年   147篇
  1977年   112篇
  1976年   110篇
  1974年   116篇
  1973年   133篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Clinical Rheumatology - Patients with rheumatoid arthritis (RA) often receive opioid analgesics for pain management. We examined the association between mental health conditions and the risk of...  相似文献   
992.
993.
There is increasing evidence for the role of exercise-based cardiac rehabilitation in the management of patients with atrial fibrillation (AF). However, this intervention has not yet been widely adopted within the National Health Service (NHS).We performed a feasibility study on the utilisation of an established NHS cardiac rehabilitation programme in the management of AF, and examined the effects of this intervention on exercise capacity, weight, and psychological health. We then identified factors that might prevent patients from enrolling on our programme.Patients with symptomatic AF were invited to participate in an established six-week exercise-based cardiac rehabilitation programme, composed of physical activity and education sessions. At the start of the programme, patients were weighed and measured, performed the six-minute walk test (6MWT), completed the Generalised Anxiety Disorder Questionnaire (GAD-7), and the Patient Health Questionnaire (PHQ-9). Measurements were repeated on completion of the programme.Over two years, 77 patients were invited to join the programme. Twenty-two patients (28.5%) declined participation prior to initial assessment and 22 (28.5%) accepted and attended the initial assessment, but subsequently withdrew from the programme. In total, 33 patients completed the entire programme (63.9 ± 1.7 years, 58% female). On completion, patients covered longer distances during the 6MWT, had lower GAD-7 scores, and lower PHQ-9 scores, compared with their baseline results. Compared with patients that completed the entire programme, those who withdrew from the study had, at baseline, a significantly higher body mass index (BMI), covered a shorter distance during the 6MWT, and had higher PHQ-9 and GAD-7 scores.In conclusion, enrolling patients with AF into an NHS cardiac rehabilitation programme is feasible, with nearly half of those invited completing the programme. In this feasibility study, cardiac rehabilitation resulted in an improved 6MWT, and reduced anxiety and depression levels, in the short term. Severe obesity, higher anxiety and depression levels, and lower initial exercise capacity appear to be barriers to completing exercise-based cardiac rehabilitation. These results warrant further investigation in larger cohorts.Key words: atrial fibrillation, cardiac rehabilitation, National Health Service  相似文献   
994.
Cone-beam CT (CBCT) using kV imagers integrated with linear accelerators is now widely used in verifying patient position during radiation therapy. Current CBCT acquisition protocols have lowered tube current to keep the imaging dose to a minimum. This affects the usability of CBCT data sets in treatment planning by reducing the soft tissue contrast and accuracy of CT numbers (Hounsfield values). The purpose of this study is to investigate the effect of reconstruction filters on full-fan and half-fan acquisition modes of CBCT and assess the image quality parameters of contrast- to -noise ratio, spatial resolution, pixel stability and uniformity. The results of this study show the relation between the noise and resolution of a CBCT image by using different reconstruction filters and provide possible estimations of the impact of filters on image quality and subsequent optimization for image-guided radiotherapy purposes.  相似文献   
995.
We examined whether outcomes of care (amputation and hospitalisation) among patients with diabetes and foot ulcer differ between those who received pre‐ulcer care from podiatrists and those who did not. Adult patients with diabetes and a diagnosis of a diabetic foot ulcer were found in the MarketScan Databases, 2005–2008. Multivariate Cox proportional hazard models estimated the hazard of amputation and hospitalisation. Logistic regression estimated the likelihood of these events. Propensity score weighting and regression adjustment were used to adjust for potentially different characteristics of patients who did and did not receive podiatric care. The sample included 27 545 patients aged greater than 65+ years (Medicare‐eligible patients with employer‐sponsored supplemental insurance) and 20 208 patients aged lesser than 65 years (non Medicare‐eligible commercially insured patients). Care by podiatrists in the year prior to a diabetic foot ulcer was associated with a lower hazard of lower extremity amputation, major amputation and hospitalisations in both non Medicare‐eligible commercially insured and Medicare‐eligible patient populations. Systematic differences between patients with diabetes and foot ulcer, receiving and not receiving care from podiatrists were also observed; specifically, patients with diabetes receiving care from podiatrists tend to be older and sicker.  相似文献   
996.
997.

Introduction

Although biomedical HIV prevention efforts have seen a number of recent promising developments, behavioural interventions have often been described as failing. However, clear lessons have been identified from past efforts, including the need to address influential social, economic and legal structures; to tailor efforts to local contexts; and to address multiple influencing factors in combination. Despite these insights, there remains a pervasive strategy to try to achieve sexual behaviour change through single, decontextualized, interventions or sets of activities. With current calls for structural approaches to HIV as part of combination HIV prevention, though, there is a unique opportunity to define a structural approach to HIV prevention as one which moves beyond these past limitations and better incorporates our knowledge of the social world and the lessons from past efforts.

Discussion

A range of interlinked concepts require delineation and definition within the broad concept of a structural approach to HIV. This includes distinguishing between “structural factors,” which can be seen as any number of elements (other than knowledge) which influence risk and vulnerability, and “structural drivers,” which should be reserved for situations where an empirically established relationship to a target group is known. Operationalizing structural approaches similarly can take different paths, either working to alter structural drivers or alternatively working to build individual and community resilience to infection. A “structural diagnostic approach” is further defined as the process one undertakes to develop structural intervention strategies tailored to target groups.

Conclusions

For three decades, the HIV prevention community has struggled to reduce the spread of HIV through sexual risk behaviours with limited success, but equally with limited engagement with the lessons that have been learned about the social realities shaping patterns of sexual practices. Future HIV prevention efforts must address the multiple factors influencing risk and vulnerability, and they must do so in ways tailored to particular settings. Clarity on the concepts, terminology and approaches that can allow structural HIV prevention efforts to achieve this is therefore essential to improve the (social) science of HIV prevention.  相似文献   
998.
Lateral humeral condyle fractures account for 17 % of the distal humeral condyle fractures. Displaced and/or rotated fractures require appropriate reduction and stabilisation. There are, however, a number of controversies in the surgical management of these patients. The aim of the present study was to review the results of patients with a displaced lateral humeral condyle fracture treated with open reduction and internal fixation (ORIF). We retrospectively reviewed children treated with ORIF of lateral humeral condyle fractures at a single institution over a period of 13 years. All cases were identified through the trauma register. Case notes and radiographs were retrieved. Fracture classification, mode of fixation, time to union, and final outcomes at the latest follow-up were reviewed. One hundred and five lateral condyle fractures were identified in 76 male and 29 female patients. Average age was 6.2 years. Ninety-two were Milch type II and 13 Milch type I. According to the Jacob’s classification, 38 were type II and 67 type III. All fractures were treated with open reduction and fixation with K-wires. Average time to radiological union was 33 days. Follow-up ranged between 2 and 8 years (average 3.2 years). Radiological hypertrophy of the lateral condyle was present in 45 cases (42 %). Three patients developed a pseudo-cubitus varus deformity. Further four patients developed a true cubitus varus. There was one case of superficial infection of the K-wires and one case of delayed union. At the latest follow-up, 96 % of the patients achieved an excellent final result and 4 % a good final result. Our results demonstrate that fracture union and excellent final outcomes can be expected in all patients using our protocol, whereby all patients with a displaced fracture are managed by ORIF with K-wire fixation, with the wires only being removed after there is evidence of radiological union. Compared to recent reports of closed reduction internal fixation, this series demonstrates good results with no complications directly relating to the open reduction technique. Level of evidence Case series, Level IV.  相似文献   
999.
Background: Mohs surgery is one of the most effective treatment options for skin cancers as it offers one of the highest chances for cure. Mohs surgery is a precise technique that removes a layer at a time. Although this may be advantageous, this treatment method is difficult in patients with immunobullous diseases. Currently the guidelines for Mohs surgery do not discuss the premanagement of immunobullous patients about to undergo Mohs surgery. Objective: To advocate for increasing prednisone dose in patients with immunobullous disease prior to undergoing Mohs surgery. Case Report: The authors present a case of an excision of a squamous cell carcinoma from a 94-year-old woman with a history of pemphigus vulgaris using Mohs micrographic surgery. Conclusion: Current preoperative guidelines for Mohs surgery do not address the issue of altering steroid medications for patients with immunobullous disease prior to the procedure. The authors suggest that patients with a history of immunobullous disease undergoing Mohs micrographic surgery should have an increase in steroid dose prior to surgery.A 94 year-old Caucasian woman with no prior history of A skin cancer presented for evaluation of a crusting Plaque on her mid-back that had been present for six months. The patient’s past medical history was significant for pemphigus vulgaris for the last 20 years for which she was on prednisone 2.5mg daily. The patient reported no allergies. She denied smoking and denied alcohol use. Review of systems was unremarkable and physical examination revealed a well-developed, well-nourished woman. Upon complete skin examination, the mid-back presented with a 5x4cm erythematous, waxy, and crusty plaque (Figure 1). The surrounding areas of skin were examined and no other suspicious lesions were noted. The lesion was biopsied and a diagnosis of squamous cell carcinoma (SCC) was established. Open in a separate windowFigure 1Left upper back—preoperativeOn the scheduled day of surgery, the patient did have a new oral ulcer on her left buccal mucosa. The patient did not exhibit any other active lesions. However, during curettage and the incision, her skin became positive for Nikolsky’s sign and the epidermis sloughed off immediately (Figure 2). The squamous cell carcinoma was then excised with wider margins using Mohs micrographic surgery (MMS) in one stage. Open in a separate windowFigure 2Left upper back—intraoperativeFurthermore, closing the lesion was very difficult (Figure 3). The defect was repaired utilizing 3-0 Vicryl and 4-0 Nylon, which were placed from opposite edges of the defect spanning the width of the opening to minimize tension at the wound edges. During microscopic examination of the frozen section, it was difficult to assess if the margins were still positive for cancer because the epidermis was not present anymore. A compression dressing consisting of xeroform was used to avoid the use of adhesive tape on surrounding tissue that had become prone to blistering. The authors’ goal was to avoid adhesives altogether, since they further traumatize the fragile skin. The patient returned for her two-week follow up for suture removal and was diagnosed with methicillin-resistant Staphylococcus aureus (MRSA) infection. This was subsequently cultured and treated with doxycycline. The patient returned one week thereafter for suture removal and healed well with no other complications. Open in a separate windowFigure 3Left upper back—postoperative  相似文献   
1000.
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