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   2538篇
  免费   167篇
  国内免费   11篇
耳鼻咽喉   63篇
儿科学   73篇
妇产科学   63篇
基础医学   272篇
口腔科学   177篇
临床医学   227篇
内科学   488篇
皮肤病学   81篇
神经病学   175篇
特种医学   46篇
外科学   346篇
综合类   63篇
一般理论   4篇
预防医学   227篇
眼科学   134篇
药学   151篇
中国医学   12篇
肿瘤学   114篇
  2023年   27篇
  2022年   55篇
  2021年   121篇
  2020年   70篇
  2019年   115篇
  2018年   93篇
  2017年   58篇
  2016年   76篇
  2015年   86篇
  2014年   101篇
  2013年   149篇
  2012年   176篇
  2011年   163篇
  2010年   112篇
  2009年   86篇
  2008年   133篇
  2007年   138篇
  2006年   116篇
  2005年   112篇
  2004年   91篇
  2003年   82篇
  2002年   54篇
  2001年   36篇
  2000年   42篇
  1999年   37篇
  1998年   17篇
  1997年   22篇
  1996年   9篇
  1994年   8篇
  1992年   18篇
  1991年   23篇
  1990年   17篇
  1989年   30篇
  1988年   19篇
  1987年   16篇
  1986年   14篇
  1985年   22篇
  1984年   14篇
  1983年   12篇
  1981年   10篇
  1979年   13篇
  1975年   6篇
  1974年   9篇
  1973年   6篇
  1972年   9篇
  1971年   12篇
  1969年   15篇
  1968年   8篇
  1967年   7篇
  1966年   7篇
排序方式: 共有2716条查询结果,搜索用时 15 毫秒
11.
Background

Cardiovascular disease (CVD) risks are of concern among immigrants and refugees settling in affluent host countries. The prevalence of CVD and risk factors among Somali African immigrants to the U.S. has not been systematically studied.

Methods

In 2015–2016, we surveyed 1156 adult Somalis in a Midwestern metropolitan area using respondent-driven sampling to obtain anthropometric, interview, and laboratory data about CVD and associated risk factors, demographics, and social factors.

Results

The prevalence of diabetes and low physical activity among men and women was high. Overweight, obesity, and dyslipidemia were also particularly prevalent. Levels of calculated CVD risk across the community were greater for men than women.

Conclusion

Though CVD risk is lower among Somalis than the general U.S. population, our results suggest significant prevalence of risk factors among Somali immigrants. Comparison with prior research suggests that CVD risks may be increasing, necessitating thoughtful intervention to prevent adverse population outcomes.

  相似文献   
12.
13.
Annals of Surgical Oncology - Telemedicine was adopted to minimize exposure risks for patients and staff during the coronavirus disease 2019 pandemic. This study measured patient satisfaction and...  相似文献   
14.
The case of a young patient with left accessory nerve paralysis is reported. He had slight tilting of the head to the right side, developed over a period of about 6 months. On neurological examination hypotrophy of the left sternocleidomastoid and trapezius muscles was observed. MRI and MR-angiography imaged the presence of a neurovascular compression between the medulla oblungata, at the level of the nerve entry zone, and a vessel loop of an elongated left vertebral artery. In spite of the absence of a surgical demonstration it is our opinion that the neurovascular conflict is the cause of the accessory nerve palsy.  相似文献   
15.
When parietal-damaged patients fail to report a contralesional stimulus because of extinction, is this because the stimulus is not perceived, or because it is perceived but cannot reach conscious awareness? VOLPE et al. [10] reported an intriguing study that seemed to locate the problem at least partly in the transfer of information to conscious awareness. They showed patients with extinction pairs of stimuli, one in each hemifield. Although patients were predictably poor at reporting the identity of the contralesional stimulus, they were able to make accurate same/different judgements comparing the two stimuli. This was interpreted as evidence that both stimuli were perceived. In the present paper, we point out that the dissociation between identification and same/different matching could also be due to the possibility that less visual information about the contralesional stimulus is necessary to make a same/different judgement than to identify the stimulus, and that chance performance is considerably higher in the first than in the second type of task. In Experiment 1, we verified this by degrading one side of a stimulus display and "replicating" the dissociation with normal subjects. We also equated the amount of visual information needed for the two tasks by yoking the stimulus pairs on "different" trials of the same/different matching task with the choice pairs on a forced choice identification task. Under these conditions, the dissociation vanished. In Experiment 2, we administered these tasks to three parietal-damaged patients with extinction. When the original method was used, same/different matching was better than identification of the contralesional stimulus. With the forced choice identification method, the dissociation again vanished.  相似文献   
16.
Behcet's disease is a chronic multisystem vasculitis that is frequent in Lebanon. The great arteries involvement is rare. We report here an unusual case of subclavian artery occlusion (pseudo-Takayasu) with a literature review.  相似文献   
17.
STUDY OBJECTIVE: The objective of this retrospective study was to report the long-term results of distal revascularization at the ankle in patients with critical ischemia. PATIENTS AND METHODS: From January 1989 to November 1999, 50 inframalleolar bypasses were performed in 49 patients (35 males and 14 females with a mean age of 75 years [range: 51 to 95 years]). Twenty-five patients (50%) were diabetics. All patients presented with critical ischemia of the lower limb. Distal anastomosis was performed at the retromalleolar posterior tibial artery in 28 cases (56%), pedal artery in 20 cases (40%) and distal fibular artery in two cases (4%). Bypasses were performed using a greater saphenous vein (n = 38), a cryopreserved arterial allograft (n = 9), or a PTFE graft (n = 2). A composite graft with greater saphenous vein and arterial allograft was performed in two cases. RESULTS: There were two early postoperative deaths. One patient presented a blow-out of the distal anastomosis that required bypass ligation and subsequent leg amputation. Early thrombosis of the graft occurred in four cases, leading to major amputation in three cases. No patients were lost to follow-up and mean follow-up was 26.7 months (range: 1 to 86 months). Graft thrombosis occurred in 15 patients and led to amputation in 6 cases. Bypass graft patency rate was 72% and 61% at 1 year and 3 years, respectively, yielding a 80% limb salvage rate at 3 years. The 3-year actuarial survival rate was 53%. CONCLUSION: Inframalleolar bypasses are a valuable tool in patients with critical ischemia. The lower limb salvage rate is satisfactory in this elderly population. Based on this experience, angiography with good run-off and, when necessary, a surgical approach to verify patency of the arteries at the ankle should always be performed before undertaking a major amputation.  相似文献   
18.
Retinoblastoma is an ocular tumor that occurs in young children, in either heritable or sporadic manner. The relative rarity of retinoblastoma, and the need for expensive equipment, anesthesia, and pediatric ophthalmologic expertise, are barriers for effective treatment in developing countries. Also, with an average age‐adjusted incidence of two to five cases per million children, patient number limits development of local expertise in countries with small populations. Lebanon is a small country with a population of approximately 4.5 million. In 2012, a comprehensive retinoblastoma program was formalized at the Children's Cancer Institute (CCI) at the American University of Beirut Medical Center, and resources were allocated for efficient interdisciplinary coordination to attract patients from neighboring countries such as Syria and Iraq, where such specialized therapy is also lacking. Through this program, care was coordinated across hospitals and borders such that patients would receive scheduled chemotherapy at their institution, and monthly retinal examinations and focal laser therapy at the CCI in Lebanon. Our results show the feasibility of successful collaboration across borders, with excellent patient and physician adherence to treatment plans. This was accompanied by an increase in patient referrals, which enables continued expertise development. However, the majority of patients presented with advanced intraocular disease, necessitating enucleation in 90% of eyes in unilateral cases, and more than 50% of eyes in bilateral cases. Future efforts need to focus on expanding the program that reaches to additional hospitals in both countries, and promoting early diagnosis, for further improvement of globe salvage rates.  相似文献   
19.
BACKGROUND/AIMS: To determine the potential of an intravitreal sustained release naproxen and 5-fluorouracil (NA/5-FU) codrug for the treatment of experimental proliferative vitreoretinopathy (PVR) in a model for trauma associated tractional retinal detachment (TRD). METHODS: Sustained release pellets were prepared by covalently linking naproxen to 5-fluorouracil. Drug release was tested in vitro and toxic effects were evaluated by electroretinography and light microscopy. Traumatic PVR was induced in pigmented rabbits by performing a scleral laceration, followed by repair and intravitreal injection of 0.4 ml of autologous blood. Thirty six eyes were treated with a sustained release implant containing 1.5 mg NA/5-FU as a codrug and 36 control eyes were submitted to surgery alone. Eyes were evaluated for TRD by serial indirect ophthalmoscope examination at different time points followed by postmortem fundus evaluation of the enucleated eye RESULTS: The NA/5-FU pellets were found to provide linear release of 5-FU and naproxen over the 30 day duration of the in vitro release test. Both the severity of PVR grade and the percentage of eyes with moderate or worse tractional detachment were significantly lower in eyes treated with the codrug pellet. There were no drug related toxic effects evident on histopathological or electroretinograph examination of eyes containing the NA/5-FU pellet. CONCLUSIONS: The results suggest that this NA/5-FU codrug device effectively inhibits the progression of PVR in a rabbit trauma model that closely resembles PVR in humans. Additional studies to add knowledge to these initial findings and to clarify the potential of the codrug device for the treatment of human PVR are warranted.  相似文献   
20.
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