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   12444篇
  免费   984篇
  国内免费   22篇
耳鼻咽喉   111篇
儿科学   497篇
妇产科学   279篇
基础医学   1556篇
口腔科学   119篇
临床医学   1504篇
内科学   2506篇
皮肤病学   210篇
神经病学   1241篇
特种医学   483篇
外科学   1550篇
综合类   117篇
一般理论   35篇
预防医学   1650篇
眼科学   124篇
药学   773篇
中国医学   35篇
肿瘤学   660篇
  2024年   25篇
  2023年   187篇
  2022年   258篇
  2021年   564篇
  2020年   335篇
  2019年   515篇
  2018年   534篇
  2017年   398篇
  2016年   375篇
  2015年   368篇
  2014年   536篇
  2013年   631篇
  2012年   1004篇
  2011年   947篇
  2010年   441篇
  2009年   377篇
  2008年   690篇
  2007年   676篇
  2006年   600篇
  2005年   561篇
  2004年   464篇
  2003年   397篇
  2002年   370篇
  2001年   161篇
  2000年   174篇
  1999年   164篇
  1998年   86篇
  1997年   72篇
  1996年   81篇
  1995年   48篇
  1994年   51篇
  1993年   42篇
  1992年   134篇
  1991年   120篇
  1990年   106篇
  1989年   82篇
  1988年   84篇
  1987年   77篇
  1986年   101篇
  1985年   88篇
  1984年   54篇
  1983年   49篇
  1982年   30篇
  1981年   40篇
  1980年   26篇
  1979年   36篇
  1978年   27篇
  1976年   21篇
  1972年   28篇
  1971年   20篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.

Introduction and hypothesis

To determine risk factors for sling revision after midurethral sling (MUS) placement.

Methods

This multicenter case-control study included patients who underwent MUS placement and subsequent revision secondary to voiding dysfunction from January 1999–2007 from nine Urogynecology centers across the USA. Direct logistic regression analysis was used to determine which diagnostic variables predicted sling revision.

Results

Of the patients, 197 met the study criteria. Patient demographics, urodynamic findings, and operative differences did not increase the risk for sling revision. Risk factors for sling revision did include: pre-existing voiding symptoms (OR 2.76, 95% CI 1.32–5.79; p?=?0.004) retropubic sling type (OR?=?2.28, 95% CI 1.08–4.78; p?=?0.04) and concurrent surgery (OR?=?4.88, 95% CI 2.16–11.05; p?<?0.001)

Conclusions

This study determined that pre-existing obstructive voiding symptoms, retropubic sling type, and concurrent surgery at the time of sling placement are risk factors for sling revision.  相似文献   
92.
93.
Background: Children and parents experience significant anxiety and distress during the preoperative period. Currently available interventions are having limited efficacy. Based on an integration of the literature in both the anesthesia and psychological milieus, the authors developed a behaviorally oriented perioperative preparation program for children undergoing surgery that targets the family as a whole.

Methods: Children and their parents (n = 408) were randomly assigned to one of four groups: (1) control: received standard of care; (2) parental presence: received standard parental presence during induction of anesthesia; (3) ADVANCE: received family-centered behavioral preparation; and (4) oral midazolam. The authors assessed the effect of group assignment on preoperative anxiety levels and postoperative outcomes such as analgesic consumption and emergence delirium.

Results: Parents and children in the ADVANCE group exhibited significantly lower anxiety in the holding area as compared with all three other groups (34.4 +/- 16 vs. 39.7 +/- 15; P = 0.007) and were less anxious during induction of anesthesia as compared with the control and parental presence groups (44.9 +/- 22 vs. 51.6 +/- 25 and 53.6 +/- 25, respectively; P = 0.006). Anxiety and compliance during induction of anesthesia was similar for children in both the ADVANCE and midazolam groups (44.9 +/- 22 vs. 42.9 +/- 24; P = 0.904). Children in the ADVANCE group exhibited a lower incidence of emergence delirium after surgery (P = 0.038), required significantly less analgesia in the recovery room (P = 0.016), and were discharged from the recovery room earlier (P = 0.04) as compared with children in the three other groups.  相似文献   

94.
Carcinoid cancers arise from the neuroendocrine cell system of the gastrointestinal tract, lungs, and other organs. Hepatic metastases are common, and patients often suffer from endocrinopathies secondary to tumor secretion of various hormones and peptides. As complete surgical resection is often not possible because of widespread disease, new therapeutic and palliative treatments are needed. In this study, we characterized the effects of suberoyl bishydroxamic acid (SBHA), a histone deacetylase inhibitor, on the growth and neuroendocrine phenotype of carcinoid cancer cells. SBHA treatment of human gastrointestinal and pulmonary carcinoid cancer cells resulted in a dose-dependent inhibition of cell proliferation. Western blot analysis showed a decrease in cyclin D1 and an increase in p21 and p27, indicating that the mechanism of this growth inhibition is cell cycle arrest. Furthermore, SBHA treatment suppressed two neuroendocrine tumor markers, chromogranin A and achaete-scute complex-like 1. These changes in the growth and neuroendocrine phenotype of carcinoid cells were associated with activation of the Notch1 signaling cascade. We conclude that SBHA shows promise as a potential anticancer agent for the treatment of patients with advanced carcinoid tumor disease. This paper was presented at the 48th Annual Meeting of the Society for Surgery of the Alimentary Tract, May 19–23, 2007, Washington, DC, USA.  相似文献   
95.
In the last four decades the survival of patients with corrected or palliated congenital heart disease has increased dramatically. However, post-operative abnormalities frequently occur and therefore a noninvasive imaging tool is mandatory for the timely detection of morphological as well as functional abnormalities. Magnetic resonance imaging (MRI) is ideally suited for the noninvasive diagnosis and post-operative follow-up of congenital heart disease. Spin-echo MRI is able to visualize structures that may be difficult to assess with other noninvasive image modalities and is sensitive in the detection of post-interventional stenoses or aneurysms. Because the function of the ventricles may deteriorate over time after correction or palliation of a congenital cardiac malformation, the use of gradient-echo MRI is essential in the follow-up after correction or palliation, as no other conventional technique allows such detailed evaluation of ventricular function, without geometrical assumptions. Phase-contrast MRI is well suited to assess valvular function, allowing accurate measurement of regurgitation or stenosis. Shunt quantification is another application of phase-contrast MRI. J. Magn. Reson. Imaging 1999;10:656-666.  相似文献   
96.
Manhattan residents living near the World Trade Center may have been particularly vulnerable to posttraumatic stress disorder (PTSD) after the September 11, 2001 (9/11) terrorist attacks. In 2003-2004, the authors administered the PTSD Checklist to 11,037 adults who lived south of Canal Street in New York City on 9/11. The prevalence of probable PTSD was 12.6% and associated with older age, female gender, Hispanic ethnicity, low education and income, and divorce. Injury, witnessing horror, and dust cloud exposure on 9/11 increased risk for chronic PTSD. Postdisaster risk factors included evacuation and rescue and recovery work. The results indicate that PTSD is a continued health problem in the local community. The relationship between socioeconomic status and PTSD suggests services must target marginalized populations. Followup is necessary on the course and long-term consequences of PTSD.  相似文献   
97.
Endoscopic pelvic osteotomy for the treatment of hip dysplasia.   总被引:2,自引:0,他引:2  
Adolescent and adult hip dysplasia can be surgically treated by rotating the acetabulum into a better weight-supporting position; however, open pelvic osteotomies are among the most invasive of all pediatric orthopaedic procedures. Endoscopic pelvic osteotomy offers the theoretical advantages of magnified visualization of the bone cuts, minimized surgical dissection, and rapid postoperative recovery. The technique of endoscopically assisted triple innominate osteotomy requires the combination of endoscopic skills and facility with more standard surgical approaches.  相似文献   
98.
BACKGROUND: Reverse total shoulder arthroplasty provides a surgical alternative to standard total shoulder arthroplasty for the treatment of selected complex shoulder problems. The purpose of the present study was to evaluate the effects of etiology on the results of reverse total shoulder arthroplasty. METHODS: Between May 1995 and June 2003, 240 consecutive reverse total shoulder arthroplasties were performed in 232 patients with an average age of 72.7 years. Patients were grouped according to etiology, and the clinical and radiographic outcomes for each group were measured and compared. RESULTS: One hundred and eighty-six patients with 191 retained reverse total shoulder arthroplasty prostheses were followed for an average of 39.9 months. Overall, the average Constant score improved from 23 points before surgery to 60 points at the time of follow-up and 173 of the 186 patients were satisfied or very satisfied with the result. Although substantial clinical and functional improvement was observed in all etiology groups, patients with primary rotator cuff tear arthropathy, primary osteoarthritis with a rotator cuff tear, and a massive rotator cuff tear had better outcomes, on average, than patients who had posttraumatic arthritis and those managed with revision arthroplasty. Dislocation (fifteen cases) and infection (eight cases) were the most common complications among the 199 shoulders that were followed for two years or were revised prior to the minimum two-year follow-up. Patients who received the reverse prosthesis at the time of a revision arthroplasty had a higher complication rate than did those who received the reverse prosthesis at the time of a primary arthroplasty. CONCLUSIONS: The reverse total shoulder arthroplasty prosthesis can produce good results when used for the treatment of a number of other complex shoulder problems in addition to cuff tear arthropathy. Patients with posttraumatic arthritis and those undergoing revision arthroplasty may have less improvement and higher complication rates in comparison with patients with other etiologies. The advanced age of the patients in the present series and the relatively short duration of follow-up suggest that the prosthesis should continue to be used judiciously.  相似文献   
99.
BACKGROUND: The incidence of venous thromboembolism (VTE) without prophylaxis is as high as 80% after major trauma. Initiation of prophylaxis is often delayed because of concerns of injury-associated bleeding. As the effect of delays in the initiation of prophylaxis on VTE rates is unknown, we set out to evaluate the relationship between late initiation of prophylaxis and VTE. METHODS: Data were derived from a multicenter prospective cohort study evaluating clinical outcomes in adults with hemorrhagic shock after injury. Analyses were limited to patients with an Intensive Care Unit length of stay >or=7 days. The rate of VTE was estimated as a function of the time to initiation of pharmacologic prophylaxis. A multivariate stepwise logistic regression model was used to evaluate factors associated with late initiation. RESULTS: There were 315 subjects who met inclusion criteria; 34 patients (11%) experienced a VTE within the first 28 days. Prophylaxis was initiated within 48 hours of injury in 25% of patients, and another one-quarter had no prophylaxis for at least 7 days after injury. Early prophylaxis was associated with a 5% risk of VTE, whereas delay beyond 4 days was associated with three times that risk (risk ratio, 3.0, 95% CI [1.4-6.5]). Factors associated with late (>4 days) initiation of prophylaxis included severe head injury, absence of comorbidities, and massive transfusion, whereas the presence of a severe lower extremity fracture was associated with early prophylaxis. CONCLUSIONS: Clinicians are reticent to begin timely VTE prophylaxis in critically injured patients. Patients are without VTE prophylaxis for half of all days within the first week of admission and this delay in the initiation of prophylaxis is associated with a threefold greater risk of VTE. The relative risks and benefits of early VTE prophylaxis need to be defined to better direct practice in this high-risk population.  相似文献   
100.
In the tropics thyroid surgery is carried out either by general surgeons or ear, nose and throat surgeons and there are few places with a subspecialist endocrine or head and neck surgeon. The aim of this review is to determine the pattern of thyroid pathology, surgery and surgical outcomes in the tropics. A review of thyroid surgery in tropical regions was carried out based on published articles in English in Medline (1965-2004). The findings are also discussed in the light of the authors' own experience of thyroid disease and thyroid surgery in four continents. The pattern of thyroid pathology varies in the tropics, particularly in regions where endemic goitre is common. Endemic goitre usually regresses with iodine therapy. There is a rising incidence of thyroid autoimmune disease, particularly Graves' disease and Hashimoto's thyroiditis, probably related to an environmental immunological stimulus associated with development. Surgery is indicated for the same reasons as in the developed countries: thyrotoxicosis (more often in the absence of radioactive iodine therapy), solitary thyroid nodule and multinodular or malignant goitre. However, a preoperative cytological diagnosis will only be available in important centres where there is a pathologist. Malignancy appears more prevalent in nodules and goitres in the tropics than in the developed countries, perhaps because patients with malignancy are more likely to be referred to a surgeon. Nonetheless, the evidence suggests that thyroid surgery can be carried out safely with a minimum of complications even in remote mission hospitals with limited facilities for investigation. Standards can be set in terms of surgical outcomes; for example, mortality (0%), permanent recurrent laryngeal nerve (RLN) injury (<2%), re-exploration for haematoma(<2%), permanent hypocalcaemia (<5%) and wound infection (2.5%). The choice of operation depends on the local pathology and the likelihood of being able to obtain lifelong thyroxine. Total thyroidectomy should be avoided whenever possible if thyroxine supplies are unreliable. Advanced thyroid cancer presents a therapeutic challenge and some cases will be unresectable. The management options are limited by the resources available. Similar surgical outcomes should be able to be achieved no matter where the surgery is carried out.  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