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   880篇
  免费   103篇
  国内免费   2篇
耳鼻咽喉   8篇
儿科学   36篇
妇产科学   9篇
基础医学   162篇
口腔科学   23篇
临床医学   83篇
内科学   144篇
皮肤病学   15篇
神经病学   43篇
特种医学   50篇
外科学   202篇
综合类   6篇
预防医学   69篇
眼科学   8篇
药学   32篇
中国医学   2篇
肿瘤学   93篇
  2022年   7篇
  2021年   10篇
  2019年   11篇
  2018年   17篇
  2017年   13篇
  2015年   12篇
  2014年   13篇
  2013年   19篇
  2012年   42篇
  2011年   38篇
  2010年   13篇
  2009年   18篇
  2008年   26篇
  2007年   28篇
  2006年   31篇
  2005年   37篇
  2004年   30篇
  2003年   22篇
  2002年   22篇
  2001年   29篇
  2000年   18篇
  1999年   25篇
  1998年   10篇
  1997年   12篇
  1996年   10篇
  1993年   9篇
  1992年   17篇
  1991年   17篇
  1990年   24篇
  1989年   26篇
  1988年   20篇
  1987年   14篇
  1986年   14篇
  1985年   19篇
  1984年   14篇
  1983年   12篇
  1980年   7篇
  1979年   31篇
  1978年   24篇
  1977年   28篇
  1976年   12篇
  1975年   19篇
  1974年   23篇
  1973年   18篇
  1972年   22篇
  1971年   12篇
  1970年   8篇
  1969年   11篇
  1968年   9篇
  1965年   10篇
排序方式: 共有985条查询结果,搜索用时 15 毫秒
51.
The optimum timing of lumbar discectomy for sciatica is imprecise. We have investigated a number of prognostic factors in relation to the outcome of radiculopathy after lumbar discectomy. We recruited 113 consecutive patients of whom 103 (91%) were followed up at one year. We found a significant association between the duration of radiculopathy and the changes in the Oswestry Disability Index score (p = 0.005) and the low back outcome score (p = 0.03). Improvement in pain was independent of all variables. Patients with an uncontained herniated disc had a shorter duration of symptoms and a better functional outcome than those with a contained herniation. Our study suggests that patients with sciatica for more than 12 months have a less favourable outcome. We detected no variation in the results for patients operated on in whom the duration of sciatica was less than 12 months.  相似文献   
52.
Background: Soccer heading has been proposed as a potential cause of cerebral dysfunction.

Objective: To examine the acute effects of two types of soccer heading on postural control.

Methods: Collegiate soccer players were randomly assigned to one of four groups: control, linear heading, simulated rotational heading, or rotational heading. Each subject completed a baseline postural stability assessment on day 1. On day 2 the same assessment was completed for the control subjects. The simulated rotational heading group completed a simulated heading drill before postural stability testing. The linear and rotational heading groups performed a heading drill with 20 balls at 88.71 km/h (55 mph), before postural stability testing. Separate one between (group), three within (surface, eyes, and day), mixed model, repeated measures analyses of variance were conducted on values for total sway and mean centre of pressure.

Results: The mixed model analysis of variance of results showed no significant differences (p>0.05) for the interactions of interest for either variable. Results suggest no acute changes in measures of postural control in soccer players completing either a linear or rotational soccer heading drill of 20 balls at a fixed speed.

Conclusion: Non-significant interactions between surface, eyes, day, and group indicate that sensory interaction of the balance mechanism components are not be compromised by the heading drill. This research supports previous studies suggesting that there are no acute risks associated with routine soccer heading. A direct comparison between these findings and those suggesting long term chronic deficits, however, cannot be made. Other studies that report chronic cerebral deficits in soccer players may have resulted from factors other than soccer heading and warrant further examination.

  相似文献   
53.
54.
Introduction To investigate the efficacy of treatment with diclofenac-cholestyramine on postoperative pain and functional outcome after total hip arthroplasty, a randomised double-blind study was conducted.Materials and methods A total of 245 patients received postoperative treatment with 75 mg or 150 mg diclofenac p.o. daily for 14 days.Results Patients who received 75 mg diclofenac per day needed paracetamol as an additional analgesic significantly more often (p=0.0162) than patients who were treated with 150 mg diclofenac daily (75 mg twice a day). The incidence of adverse gastrointestinal events was significantly lower in the group receiving 75 mg diclofenac daily than in the group receiving the higher dose (23.1% vs 37.1%; p=0.025). Six months after the operation, no differences were observed between the two groups with regard to pain or functionality measured in terms of overall mobility of the hip. No patient of either group developed clinically relevant heterotopic ossifications.Conclusion Treatment with a dose of 75 mg diclofenac once daily—if necessary with the additional use of paracetamol—is a favourable option for the postoperative care of THA.  相似文献   
55.
The purpose of this study was to assess the outcome of peri-radicular infiltration for radicular pain in patients with spinal stenosis and lumbar disc herniation (LDH). Patients with spinal stenosis ( n=62) or LDH ( n=55) who met our criteria received fluoroscopically guided peri-radicular infiltration of local anaesthetic and steroid at the site of documented pathology. All the patients were followed-up at 3 months. There was a statistically significant difference in the functional outcome between the spinal stenosis group and the LDH group. The mean change in the Oswestry disability index (ODI) score for the spinal stenosis group was 5.5% compared to 12% for the LDH group. The spinal stenosis group had a mean change in visual analogue scales (VAS) of 1.2 compared to 2 for the LDH group. The higher the modified somatic perception score, modified zung depression and age at injection, the less favourable the outcome. There was a significantly better response to peri-radicular infiltration for radicular pain in patients with LDH than the spinal stenosis. Our findings help us to provide a better information for future patients. We do not know if this is a treatment effect or natural history of the pathology, as this is a cohort study and not a randomised controlled trial.  相似文献   
56.
Chordomas are rare, slow-growing and often recurrent neoplasms being composed of various cell types (physaliferous, epitheloid, chondroid), thus, showing a wide range of histological features. To study the relationship between histological and immunohistochemical pattern and biological behavior according to different cell types, the authors studied 33 specimens of 17 patients with and without recurrent tumors. Additionally, the histological features according to nuclear atypia and mitotic activity of both groups were analyzed and compared with each other. Predominance of one cell type was observed in 19 specimens (10 were composed mainly of physaliferous, 8 of the epitheloid and one of chondroid cell type). In 7 cases, areas of chondroid differentiation were present. MIB proliferation index tended not to be higher in recurrent tumors but in cases with nuclear atypia and nuclear pleomorphism seems to be predictive for recurrency. Immunohistochemically, nearly all cell types (physaliferous, epithelial-like and cells of chondroid differentiation) of both recurrent and non recurrent chordomas stained positive for epithel membrane antigen (EMA), cytokeratins (KL1, AE1/AE3), S100, vimentin and negative for HMB45 and desmin. Positive staining for NSE was observed in 70% of cases, however, the chondroid componente stained negative in every case.  相似文献   
57.
We have recently shown that activation of the immune system with lipopolysaccharide (LPS) results in memory-processing deficits for the passive avoidance learning task in the day-old chick. The current study examined two important issues in understanding the mechanisms underlying these memory deficits associated with immune system activation, namely, whether LPS (1) impairs Na(+)/K(+)-ATPase functioning and (2) increases corticosterone (CORT) concentrations in chicks trained on the task. As the effects of LPS on sickness behavior have only previously been characterized in older chickens, this study also tested whether LPS is able to produce similar alterations in day-old chicks. LPS decreased brain Na(+)/K(+)-ATPase activity and increased plasma concentrations of CORT in chicks trained on the passive avoidance learning task. These findings give an insight into some of the mechanisms that may be responsible for the LPS-induced memory-processing deficits. Consistent with previous research in older chickens, LPS increased body temperature in a dose-dependent manner, however, only the lowest dose of LPS tested significantly decreased food intake in the day-old chicks.  相似文献   
58.
59.
60.
Postoperative irradiation of the operative field is an established method to prevent heterotopic ossification in total hip arthroplasty. In this study two theoretical dose-equivalent regimens of radiation therapy were compared. Allogenic bone matrix was implanted in both thighs of 50 adult male Wistar rats to induce heterotopic ossification. Immediately after operation the implants of 40 animals were irradiated using a single-dose of 7 Gy or 5 fractions of 2 Gy each. Ten rats served as a controlgroup and did not undergo irradiation. Radiation therapy with 5 x 2 Gy led to a highly significantly better suppression of heterotopic ossification than irradiation with 1 x 7 Gy (p < 0.001; paired-t-test). Single-dose irradiation reduced the mean calcium contents to 138.87 +/- 22.84 micrograms Ca2+/mg implanted bone matrix; fractionated irradiation obtained a reduction to 63.35 +/- 21.16 micrograms Ca2+/mg implanted bone matrix. In thigh implants not exposed to irradiation the mean calcium content was 191.50 +/- 11.46 micrograms Ca2+/mg implanted bone matrix. Radiographically better suppression of bone formation could be documented after irradiation with 5 x 2 Gy compared to 1 x 7 Gy and non-irradiated implants. The histological aspect of the explanted specimens showed quantitatively more new bone formation in the non-irradiated controls than in both irradiation groups. In view of experimentally demonstrated better effects, as well as the reduced side effects, fractionated irradiation appears preferable.  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