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   1384篇
  免费   88篇
  国内免费   12篇
耳鼻咽喉   1篇
儿科学   73篇
妇产科学   16篇
基础医学   121篇
口腔科学   155篇
临床医学   128篇
内科学   198篇
皮肤病学   9篇
神经病学   39篇
特种医学   84篇
外科学   261篇
综合类   13篇
预防医学   75篇
眼科学   47篇
药学   59篇
肿瘤学   205篇
  2022年   5篇
  2021年   20篇
  2020年   12篇
  2019年   25篇
  2018年   36篇
  2017年   21篇
  2016年   13篇
  2015年   25篇
  2014年   35篇
  2013年   42篇
  2012年   56篇
  2011年   58篇
  2010年   44篇
  2009年   36篇
  2008年   58篇
  2007年   79篇
  2006年   70篇
  2005年   74篇
  2004年   54篇
  2003年   55篇
  2002年   44篇
  2001年   46篇
  2000年   55篇
  1999年   55篇
  1998年   39篇
  1997年   29篇
  1996年   25篇
  1995年   16篇
  1994年   19篇
  1993年   21篇
  1992年   33篇
  1991年   22篇
  1990年   25篇
  1989年   22篇
  1988年   14篇
  1987年   16篇
  1986年   12篇
  1985年   22篇
  1984年   17篇
  1983年   8篇
  1980年   8篇
  1979年   7篇
  1977年   13篇
  1976年   12篇
  1975年   8篇
  1974年   7篇
  1970年   7篇
  1969年   7篇
  1967年   8篇
  1966年   7篇
排序方式: 共有1484条查询结果,搜索用时 19 毫秒
21.
Objectives: A prospective study comparing the efficiacy and side-effects of oral sulindac with intravenous indomethacin in clinically stable preterm infants (<1750 g) requiring non-invasive closure of haemodynamically significant patent ductus arteriosus.
Methodology: As maturity and birthweight are the two major determinants of ductal closure, infants were matched as closely as possible for these parameters. An eligible patient was first assigned to the sulindac group and a subsequent patient with similar gestational age (± 1 week) and birthweight (±100 g) to the previously recruited infant would automatically receive indomethacin. A total of eight infants were enrolled in each group.
Results: The ductus arteriosus was successfully closed in all eight infants receiving indomethacin, and in seven of eight infants receiving sulindac. No significant differences were found with regards to the ductal size between the two groups at diagnosis or on each of the consecutive days of treatment ( P >0.25). More renal adverse effects were encountered in the indomethacin group. Significant differences in changes from baseline value for urine output, plasma sodium, urea and creatinine concentrations were noted at 24, 48 and 72 h after commencement of treatment between the two groups ( P <0.05). All the parameters returned to normal or pre-treatment levels 48 h after stopping therapy. Unexpectedly, severe gastrointestinal complications were encountered in the sulindac group.
Conclusions: Sulindac is capable of promoting ductal constriction in clinically stable preterm infants without compromising the renal function. The spectrum of gastrointestinal complications observed in sulindac treated infants were similar to those described for indomethacin. The use of sulindac for ductal closure in the preterm infant should remain experimental.  相似文献   
22.
The level of satisfaction with telepsychiatry evaluations was determined in a sample of 43 forensic psychiatric patient inmates in a large urban jail. A forensic psychiatrist interviewed 20 patients in person, the other 23 remotely via interactive video. Demographic characteristics, physical health status, and psychiatric symptom severity on the Global Severity Index of the Brief Symptom Inventory were comparable in the two groups. Patient satisfaction with the evaluations was moderately high for patients in both groups, with no significant differences between them.  相似文献   
23.
24.
25.
The effect of body composition on the thermal and metabolic responses of 24 male volunteers (20 to 35 years) was examined during 90 min of moderately cold (18, 22, or 26 degrees C) water immersion to the first thoracic vertebrae. Body composition was determined via underwater densitometry. Subjects were divided with respect to body fat (high fat (HF) = 18-22%, n = 12; Low fat (LF) = 8-12%, n = 12) and randomly assigned to one of three water temperatures. Rectal temperature (degree C) after 90 min of immersion did not differ in LF and HF at 18 degrees C (35.9 vs. 36.2), 22 degrees C (36.0 vs. 36.0), and 26 degrees C (36.0 vs. 36.3). Oxygen uptake (VO2, ml-kg-1.min-1) was greater in LF than in HF in all water temperatures. Oxygen uptake at 90 min was greater for LF than HF in 18 degrees C (11.48 vs. 9.19), 22 degrees C (9.79 vs. 4.70), and 26 degrees C (6.21 vs. 5.44). Mean skin temperature in LF and HF approached water temperature within the first 5 min. Despite the thermal strain of cold water immersion, the LF subjects were able to maintain a similar Tre compared to the HF due to a significantly greater shivering thermogenesis.  相似文献   
26.
Trauma to the spinal cord creates an initial physical injury damaging neurons, glia, and blood vessels, which then induces a prolonged inflammatory response, leading to secondary degeneration of spinal cord tissue, and further loss of neurons and glia surrounding the initial site of injury. Angiogenesis is a critical step in tissue repair, but in the injured spinal cord angiogenesis fails; blood vessels formed initially later regress. Stabilizing the angiogenic response is therefore a potential target to improve recovery after spinal cord injury (SCI). Vascular endothelial growth factor (VEGF) can initiate angiogenesis, but cannot sustain blood vessel maturation. Platelet-derived growth factor (PDGF) can promote blood vessel stability and maturation. We therefore investigated a combined application of VEGF and PDGF as treatment for traumatic spinal cord injury, with the aim to reduce secondary degeneration by promotion of angiogenesis. Immediately after hemisection of the spinal cord in the rat we delivered VEGF and PDGF and to the injury site. One and 3 months later the size of the lesion was significantly smaller in the treated group compared to controls, and there was significantly reduced gliosis surrounding the lesion. There was no significant effect of the treatment on blood vessel density, although there was a significant reduction in the numbers of macrophages/microglia surrounding the lesion, and a shift in the distribution of morphological and immunological phenotypes of these inflammatory cells. VEGF and PDGF delivered singly exacerbated secondary degeneration, increasing the size of the lesion cavity. These results demonstrate a novel therapeutic intervention for SCI, and reveal an unanticipated synergy for these growth factors whereby they modulated inflammatory processes and created a microenvironment conducive to axon preservation/sprouting.  相似文献   
27.
Resection arthroplasty of the first metatarsophalangeal joint is a well-known operation. The follow-up results more than 17 years after arthroplasty for hallux valgus are reported and discussed. Between 1971 and 1980, 335 resection arthroplasties were performed on 205 patients. The sole indication for resection arthroplasty of the great toe in this study was hallux valgus. The technique involved removal of the proximal one-third of the phalanx with interposition of a capsular flap, occasionally including temporary Kirschner wire fixation. After 17.6 years on average, 102 patients were re-examined clinically and radiographically. Questionnaire assessment revealed a significantly prolonged walking distance, and 70% of the patients were pain-free at follow-up investigation, whereas 67% suffered from severe pain before the operation. Clinical evaluation showed diminished weight-bearing of the great toe during walking and a reduced range of motion of the resected first metatarsophalangeal joint. Radiographic shortening of the proximal phalanx was 37%. The average hallux valgus anlge was 23° at follow-up and 34° prior to surgery. The unacceptably high rate of hallux valgus relapse, especially due to a high intermetatarsal angle, emphasizes the unsatisfactory long-term results of the resection arthrosplasty. We now recommend this operation for older patients only, and a differentiated approach using reconstructive procedures according to the clinical and radiographical situation for younger patients. Received: 29 September 1997  相似文献   
28.
Symptomatic shoulder instability due to lesions of the glenoid labrum   总被引:1,自引:0,他引:1  
Lesions of the glenoid labrum can be associated with and cause shoulder instability and symptomatology by (1) allowing the shoulder to dislocate recurrently (anatomical instability); (2) allowing the shoulder to subluxate (anatomical instability); and (3) allowing the shoulder to click, catch, and lock secondary to partially attached fragments becoming interposed between the articular surfaces (functional instability). The latter two clinical entities are usually associated with "lesser" labral damage and diagnosis can be difficult. Six illustrative cases are presented and salient diagnostic and therapeutic points are discussed. The glenohumeral axillary arthrotomogram is presented as a sensitive diagnostic test for detecting labral lesions.  相似文献   
29.

Objective

To determine the accuracy of MR imaging for the evaluation of the subscapularis tendon as well as define imaging findings that will increase accuracy.

Materials and methods

Retrospective review of the MR and operative (OR) reports of 286 patients was conducted and reviewed for the presence/degree (partial (PT)/full-thickness (FT)) of tearing; only PT articular tears were included. The presence of a supraspinatus tear and time interval between surgery and MRI were also documented. All of the PT tears called on MRI were also reviewed to see if there was a statistically significant association between certain imaging characteristics and the presence of a tear in surgery. Statistical analysis included 95 % confidence intervals, Fisher’s exact, and exact Mann–Whitney tests.

Results

A total of 244 patients were included in the study with a total of 25 subscapularis tears, 16 PT and nine FT, and 219 intact tendons in arthroscopy; 20/25 tears and 200 intact tendons were diagnosed correctly on MRI, resulting in sensitivity of 80 %, specificity of 91 %, accuracy of 90 %, positive predictive value of 51 %, and negative predictive value of 98 %. There was a significant association between the presence of a PT tear during arthroscopy and fluid-like signal within the tendon on more than one imaging plane (p?<?0.001) with an accuracy of 90 %.

Conclusions

This study reflects a musculoskeletal radiology section’s experience with the diagnosis of subscapularis tendon pathology, demonstrating that MRI could be used to accurately evaluate the subscapularis tendon. An understanding of certain imaging pitfalls and the presence of fluid-like signal on multiple imaging planes should increase the diagnostic accuracy of the radiologist evaluating the subscapularis tendon for the presence of a tear.  相似文献   
30.
In patients with early-stage breast cancer, all recurrences are associated with an increased risk of mortality, especially distant metastases. Adjuvant tamoxifen therapy for 5 years is effective in postmenopausal patients for the prevention of disease recurrence but is associated with increased risk of rare, potentially fatal adverse events such as endometrial cancer, stroke, and pulmonary embolism. Recently, randomized clinical trials have shown aromatase inhibitor therapy to be superior to tamoxifen therapy for the prevention of disease recurrence. Switching to an aromatase inhibitor after 2-3 years of tamoxifen treatment has been shown to provide superior disease-free survival compared with completing 5 years of tamoxifen. Among approved aromatase inhibitors (letrozole, anastrozole, and exemestane), letrozole is the only one approved as extended adjuvant therapy after completing 5 years of tamoxifen. These results suggest that 10 years of adjuvant endocrine therapy is superior to 5 years of tamoxifen alone.  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