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   1524篇
  免费   88篇
  国内免费   10篇
耳鼻咽喉   13篇
儿科学   96篇
妇产科学   15篇
基础医学   170篇
口腔科学   29篇
临床医学   101篇
内科学   445篇
皮肤病学   29篇
神经病学   96篇
特种医学   37篇
外科学   270篇
综合类   5篇
预防医学   23篇
眼科学   1篇
药学   101篇
中国医学   4篇
肿瘤学   187篇
  2023年   8篇
  2021年   29篇
  2020年   15篇
  2019年   31篇
  2018年   26篇
  2017年   27篇
  2016年   36篇
  2015年   39篇
  2014年   57篇
  2013年   56篇
  2012年   92篇
  2011年   77篇
  2010年   49篇
  2009年   49篇
  2008年   78篇
  2007年   109篇
  2006年   122篇
  2005年   82篇
  2004年   75篇
  2003年   79篇
  2002年   78篇
  2001年   20篇
  2000年   15篇
  1999年   21篇
  1998年   31篇
  1997年   44篇
  1996年   33篇
  1995年   24篇
  1994年   24篇
  1993年   24篇
  1992年   19篇
  1991年   10篇
  1990年   11篇
  1989年   8篇
  1988年   7篇
  1987年   7篇
  1986年   6篇
  1985年   10篇
  1984年   4篇
  1983年   5篇
  1981年   4篇
  1980年   4篇
  1979年   5篇
  1978年   5篇
  1958年   18篇
  1957年   8篇
  1956年   10篇
  1955年   4篇
  1954年   6篇
  1940年   2篇
排序方式: 共有1622条查询结果,搜索用时 312 毫秒
51.
Adenoid cystic carcinoma (ACC) of the head and neck region is an uncommon epithelial tumor of the major and minor salivary glands. In the oral region, although ACC arising from the minor salivary glands is the second most commonly found tumor in the tongue base, its occurrence in the anterior part of the tongue is rare. Histopathologically, ACC is categorized into three growth patterns (tubular, cribriform, and solid types) and three histologic grades (I?CIII) that are based on the proportions of these patterns. According to this classification, tubular- and cribriform-type ACCs are considered to be lower grade lesions, while solid-type ACCs are considered to be higher grade lesions. A fourth histopathological type has recently been reported by some authors, namely, dedifferentiation or high-grade transformation of ACC. However, very few studies have focused on the imaging features of these ACCs. We report here the case of a 63-year-old female patient with ACC of the tongue with dedifferentiated components, together with the radiological images and pathological features of this ACC.  相似文献   
52.
ObjectivesA global consensus on how to treat recurrent pancreatic cancer after adjuvant chemotherapy with gemcitabine (ADJ-GEM) does not exist.MethodsWe retrospectively reviewed the clinical data of 41 patients with recurrences who were subsequently treated with chemotherapy.ResultsThe patients were divided into two groups according to the time until recurrence after the completion of ADJ-GEM (ADJ-Rec): patients with an ADJ-Rec < 6 months (n = 25) and those with an ADJ-Rec ≥ 6 months (n = 16). The disease control rate, the progression-free survival after treatment for recurrence and the overall survival after recurrence for these two groups were 68 and 94% (P = 0.066), 5.5 and 8.2 months (P = 0.186), and 13.7 and 19.8 months (P = 0.009), respectively. Furthermore, we divided the patients with an ADJ-Rec < 6 months into two groups: patients treated with gemcitabine (n = 6) and those treated with alternative regimens including fluoropyrimidine-containing regimens (n = 19) for recurrent disease. Patients treated with the alternative regimens had a better outcome than those treated with gemcitabine.ConclusionsFluoropyrimidine-containing regimens may be a reasonable strategy for recurrent disease after ADJ-GEM and an ADJ-Rec < 6 months.  相似文献   
53.

Purpose

Although a pancreaticoduodenectomy (PD) has been recently regarded as a safe surgical procedure at high-volume centers, the efficacy of PD for patients 80 years of age and older is controversial. The aim of this study was to evaluate the perioperative and long-term outcomes following PD in patients 80 years of age and older.

Methods

Elderly patients 80 years of age and older who underwent PD between 2001 and 2009 were identified. The perioperative and long-term outcomes were compared with patients younger than 80 years of age.

Results

Of 561 total patients, 22 patients (3.9 %) were 80 years of age or older. Mortality occurred in one patient (4.5 %). Postoperative major complications (Clavien–Dindo classification ≥grade III) occurred in six patients (27.3 %) in this group, which was significantly higher than in patients younger than 80 years of age (P?=?0.008). The survival of the elderly patients undergoing PD for pancreatic cancer was significantly shorter than that for the same patient group with other diseases (median survival, 13 versus 82 months; P?=?0.014). Only one elderly patient with pancreatic cancer survived more than 3 years.

Conclusions

PD for pancreatic cancer in patients aged 80 and older should be carefully selected, because it is associated with a higher incidence of severe postoperative complications and a small change of long-term survival.  相似文献   
54.
55.
A patient presented with malignant melanoma of the parotid gland with no obvious primary lesions, which was treated by total parotidectomy with excision of skin. Despite radiotherapy for brain metastases and combination chemotherapy for lung and lymph node metastases, she died 13 months after the initial operation.  相似文献   
56.

Objective

The characteristic pathological muscular findings of polymyositis (PM) and dermatomyositis (DM) have been shown to reflect their different pathogeneses. Here, we characterized the muscle biopsy findings of PM and DM patients with or without malignancy.

Methods

We evaluated the muscle biopsy findings of 215 consecutive PM and DM patients admitted to our hospital between 1970 and 2009. Pathology of the lesion biopsy sections was classified into 3 types: endomysial infiltration-type, perivascular infiltration-type, and rare-infiltrative-type.

Results

There was no difference between the muscle pathology of PM patients with and without malignancy. However, the incidence of rare-infiltrative type muscle pathology in DM patients with malignancy was significantly higher than in those without such tumors (p = 0.0345).

Conclusion

The incidence of rare-infiltrative type muscle pathology may be a predictive marker of DM with malignancy.  相似文献   
57.
58.
59.

Background

A retrospective analysis indicated that the incidence of delayed gastric emptying (DGE) was less after using a circular stapler (CS) for duodenojejunostomy than that after hand-sewn (HS) anastomosis in pylorus-preserving pancreaticoduodenectomy (PpPD). This randomized clinical trial compared the incidence of DGE postoperative after CS duodenojejunostomy with that of conventional HS anastomosis in PpPD.

Methods

We randomly assigned 101 patients (age 20–80) undergoing PpPD to receive CS duodenojejunostomy (group CS, n?=?50) or HS duodenojejunostomy (group HS, n?=?51) in two Japanese cancer center hospitals between 2011 and 2013. The patients were stratified by institution and size of the main pancreatic duct (<3 or ≥3 mm). The primary endpoint was the incidence of grade B or C DGE according to the international definition with a non-inferiority margin of 5 %. This trial is registered with University hospital Medical Information Network (UMIN) Center: UMIN000005463.

Results

Per-protocol analysis of data on 95 patients showed that grade B or C DGE was found in 4 (8.9 %) of 45 patients who underwent CS anastomosis and in 8 (16 %) of 50 patients who underwent HS anastomosis (P?=?0.015). There were no differences in the overall incidence of DGE (P?=?0.98), passage of the contrast medium through the anastomosis (P?=?0.55), or hospital stays (P?=?0.22).

Conclusions

CS duodenojejunostomy is not inferior to HS anastomosis with respect to the incidence of clinically significant DGE, justifying its use as treatment option.
  相似文献   
60.
Carotid endarterectomy (CEA) is intended to remove atheromatous plaque by dissecting a plane between the intima and the media (circular medial fibers), but this may not be the optimal dissection plane. The present technique is based on identifying the plane that divides the media from the plaque, so preserving the media on the adventitia as much as possible. This plane is more difficult to find and follow than the easy-to-dissect plane usually located between the media and the adventitia, because the plaque invades the media and so the dividing plane is located within the media. In this prospective observational study, CEA was performed in 22 patients to histologically examine the excised plaques and small samples of the whole arterial wall, and evaluate the clinical outcomes. Plaque had invaded the luminal part of the media in the whole arterial wall sample of 80% of cases. Thin medial layers covering > 80% of the surface of the plaque were found in 16 of 22 plaques (73%). Some atheromatous component was sometimes left in the preserved media, rather than completely removed with the media. No morbidity or mortality had occurred by discharge. Only 1 small ipsilateral infarction (4.5%) and no restenosis of greater than 50% were detected during the mean follow-up period of 7 years. Since the plaque usually invades the media, the optimum dissection plane may be located within the media, dividing it into two layers. The presence of some remnant atheromatous components in the preserved media was not associated with surgical complications or restenosis.  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