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   17223篇
  免费   969篇
  国内免费   142篇
耳鼻咽喉   139篇
儿科学   397篇
妇产科学   356篇
基础医学   1882篇
口腔科学   460篇
临床医学   1862篇
内科学   3966篇
皮肤病学   206篇
神经病学   1839篇
特种医学   498篇
外科学   2398篇
综合类   73篇
现状与发展   1篇
一般理论   12篇
预防医学   1310篇
眼科学   353篇
药学   949篇
中国医学   22篇
肿瘤学   1611篇
  2024年   16篇
  2023年   143篇
  2022年   287篇
  2021年   550篇
  2020年   304篇
  2019年   512篇
  2018年   553篇
  2017年   442篇
  2016年   430篇
  2015年   510篇
  2014年   747篇
  2013年   925篇
  2012年   1324篇
  2011年   1436篇
  2010年   737篇
  2009年   669篇
  2008年   1228篇
  2007年   1200篇
  2006年   1073篇
  2005年   1074篇
  2004年   1014篇
  2003年   892篇
  2002年   808篇
  2001年   108篇
  2000年   80篇
  1999年   114篇
  1998年   144篇
  1997年   114篇
  1996年   106篇
  1995年   105篇
  1994年   77篇
  1993年   68篇
  1992年   49篇
  1991年   46篇
  1990年   49篇
  1989年   45篇
  1988年   37篇
  1987年   32篇
  1986年   28篇
  1985年   30篇
  1984年   26篇
  1983年   33篇
  1982年   32篇
  1981年   21篇
  1980年   19篇
  1979年   21篇
  1978年   11篇
  1977年   11篇
  1975年   6篇
  1974年   7篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Sport Sciences for Health - The practice of physical activity has been recommended during the pandemic period of COVID-19 as a way of preventing the worsening of physical and mental health. After...  相似文献   
102.
Abstract: Ductal carcinoma in situ (DCIS) describes a wide spectrum of non‐invasive tumors which carry a significant risk of invasive relapse, thus prevention of local recurrence is vital. For appropriate patients with limited disease, management with breast conserving surgery (BCS) followed by whole‐breast radiation (RT) is supported by multiple Phase III studies, but mastectomy may be appropriate in selected patients. Omission of RT may also be reasonable in some patients, though which criteria are to be utilized remain unclear, and the existing data are contradictory with limited follow‐up. Various RT techniques such as boost to the tumor bed, partial breast radiation or hypofractionated, whole‐breast RT are increasingly utilized but the data to support their use specifically in DCIS is limited. Tamoxifen also increases local control for ER + DCIS, adding to the complexity of the local treatment management. This article reviews the existing scientific evidence, the controversies surrounding local management, and clinical guidelines for DCIS based on the group consensus by the ACR Breast Expert Panel. The American College of Radiology Appropriateness Criteria are evidence‐based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer‐reviewed journals and the application of a well established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.  相似文献   
103.
Despite much advancement in preoperative evaluation and perioperative care of patients with thoracoabdominal aortic aneurysms (TAAA), open surgical repair of TAAAs remains a formidable challenge for the vascular surgeon. It requires extensive dissection and mobilization of the aorta and its branches, as well as cross-clamping of the aorta above intercostal and visceral arteries. Over the past decade, the mortality and morbidity associated with open TAAA repair have improved significantly. However, it remains one of the most complex, extensive surgical procedures performed in the field of vascular surgery. Recently, there has been much attention directed at less invasive methods such as the so-called "hybrid" or "debranching" procedure, or complete endovascular repair with fenestrated and branched endografts for repairing TAAAs. However, the gold standard for repair of TAAA remains open surgery, and this article summarizes the clinical outcomes of open surgical repair of TAAAs during the past decade (2000-2010) to provide a benchmark for comparison with results from previous decades and also with which to compare the results of modern-day hybrid and/or complete endovascular techniques.  相似文献   
104.

Background

Information from randomized trials on the role of combination chemotherapy in the adjuvant treatment of pancreatic adenocarcinoma is limited. This randomized phase II trial aimed to identify the most promising regimen warranting phase III evaluation.

Methods

Therapy-naive patients, age 18?C75?years, Karnofsky Performance Status (KPS) >60, gross total resection of stage IB?CIII pancreatic adenocarcinoma, stratified for center and surgical margins, were randomly assigned to receive either gemcitabine 1?g/m2 weekly on days 1, 8, and 15 (arm A) or the PEFG regimen (cisplatin and epirubicin 40?mg/m2, day 1; gemcitabine 600?mg/m2, days 1, 8; 5-fluorouracil 200?mg/m2 daily, days 1?C28) (arm B). Chemotherapy was administered every 4?weeks for 3?months and followed by irradiation concurrent to continuous infusion of 5-fluorouracil 250?mg/m2 daily. Primary endpoint was the probability of being disease-free at 1?year from surgery. Assuming P0?=?35% and P1?=?55%, ???=?.05 and ???=?.10, the study was to enroll 51 patients per arm.

Results

A total of 102 patients were randomized; 100 were eligible (arm A: 51; arm B: 49). Baseline characteristic (A/B) were: Median age was 61/60?years; 75% had KPS >80 75/76%; 36% grade 3 tumor 29/43%, 79% stage IIB/III 75/84%, 31% R1 resection 35/29%. Survival figures (A/B) were: Median disease-free survival was 11.7 and 15.2?months; 1-year disease-free survival 49.0% (95% confidence interval [95% CI] 35?C63%) and 69.4% (95% CI 56?C83%); median survival 24.8 and 28.9?months. Combination chemotherapy produced more hematological toxicity without relevant differences in nonhematological toxicities.

Conclusions

The 4-drug regimen deserves further assessment in resectable pancreatic cancer.  相似文献   
105.

Background

Complete pathologic response (CPR) after neoadjuvant chemoradiotherapy (combined modality treatment, CMT) for rectal cancer seems associated with improved survival compared to partial or no response (NPR). However, previous reports have been limited by small sample size and single-institution design.

Methods

A systematic literature review was conducted to detect studies comparing long-term results of patients with CPR and NPR after CMT for rectal cancer. Variables were pooled only if evaluated by 3 or more studies. Study end points included rates of CPR, local recurrence (LR), distant recurrence (DR), 5-year overall survival (OS), and disease-free survival (DFS).

Results

Twelve studies (1,913 patients) with rectal cancer treated with CMT were included. CPR was observed in 300 patients (15.6%). CPR and NPR patient groups were similar with respect to age, sex, tumor size, distance of tumor from the anus, and stage of disease before treatment. Median follow-up ranged from 23 to 46?months. CPR patients had lower rates of LR [0.7% vs. 2.6%; odds ratio (OR) 0.45, 95% confidence interval (CI) 0.22?C0.90, P?=?0.03], DR (5.3% vs. 24.1%; OR 0.15, 95% CI 0.07?C0.31, P?=?0.0001), and simultaneous LR?+?DR (0.7% vs. 4.8%; OR 0.32, 95% CI 0.13?C0.79, P?=?0.01). OS was 92.9% for CPR versus 73.4% for NPR (OR 3.6, 95% CI 1.84?C7.22, P?=?0.002), and DFS was 86.9% versus 63.9% (OR 3.53, 95% CI 1.62?C7.72, P?=?0.002).

Conclusions

CPR after CMT for rectal cancer is associated with improved local and distal control as well as better OS and DFS.  相似文献   
106.

Background

Simple tumor enucleation (TE) showed excellent oncologic results in large retrospective series. No study has compared oncologic outcomes after TE and radical nephrectomy (RN) for the treatment of pT1 renal cell carcinoma (RCC). The aim of the present study is to compare the oncologic outcomes after TE and RN in pT1 RCCs.

Methods

We retrospectively analyzed 475 patients who underwent TE or RN for pT1 RCC, N0, M0, between 1995 and 2007. TE was performed in 332 patients and RN in 143. Local recurrence, progression-free survival (PFS), and cancer-specific survival (CSS) were the main outcomes of this study. The Kaplan-Meier method was used to calculate survival functions, and differences were assessed with the log rank statistic. Univariate and multivariate Cox regression models were also used.

Results

The 5- and 10-year PFS estimates were 91.3 and 88.7% after RN and 95.3 and 92.8% after TE (P?=?NS), respectively. The 5- and 10-year CSS estimates were 92.1 and 89.4% after RN and 94.4% (5- and 10-year CSS) after TE (P?=?NS), respectively. No statistically significant differences between RN and TE were found after adjusting CSS probabilities according to age at surgery, grade, stage, or clear cell subtype. Surgical treatment was not a predictor of PFS or CSS by both univariate and multivariate analyses. The potential limitation of this study is that the data originate from a retrospective review.

Conclusions

TE can achieve oncologic results similar to those of RN for the treatment of pT1 RCCs, provided tumors are carefully selected on the basis of their safe and complete removal.  相似文献   
107.
108.

Introduction

Gemcitabine is standard treatment for pancreatic cancer but has limited clinical benefit due to chemoresistance. Nuclear factor-kappaB (NF-??B) can promote chemoresistance and is therefore an attractive therapeutic target. We hypothesize that NF-??B suppression with the novel, orally bioavailable inhibitor dimethylamino parthenolide (DMAPT) will sensitize pancreatic cancer cells to gemcitabine.

Methods

BxPC-3, PANC-1, and MIA PaCa-2 human pancreatic cancer cell lines were treated with gemcitabine and/or DMAPT. Effects on the NF-??B pathway were determined by electrophoretic mobility shift assay, ELISA, or Western blot. Proliferation and apoptosis were measured by cell counts and ELISA, respectively. The effect of gemcitabine in vivo was determined using a MIA PaCa-2 heterotopic xenograft model.

Results

Gemcitabine induced NF-??B activity in BxPC-3, PANC-1, and MIA PaCa-2 cells and decreased the level of the NF-??B inhibitor I??B?? in BxPC-3 and PANC-1 cells. DMAPT prevented the gemcitabine-induced activation of NF-??B. The combination of DMAPT/gemcitabine inhibited pancreatic cancer cell growth more than either agent alone. Gemcitabine also induced intratumoral NF-??B activity in vivo.

Conclusions

DMAPT enhanced the anti-proliferative effects of gemcitabine in association with NF-??B suppression in pancreatic cancer cells in vitro. Furthermore, gemcitabine induced NF-??B activity in vivo, thus supporting the evaluation of NF-??B-targeted agents to complement gemcitabine-based therapies.  相似文献   
109.

Background

The positioning of an intragastric saline-filled balloon has been developed as temporary and reversible therapeutic option for treatment of morbid obesity. Recently, an air-filled balloon was also developed. The aim of this study is to prospectively compare these two devices in terms of weight loss parameters, safety, and tolerance.

Methods

Sixty patients were randomized into two groups: group A (Bioenterics Intragastric Balloon?CBIB; n?=?30; 20?F/10?M, mean age 36.7?±?10.9; mean BMI 46.5?±?5.9) and group B (Endobag-Heliosphere; n?=?30; 20?F/10?M, mean age 37.8?±?10.6; mean BMI 46.1?±?5.6). All patients of both groups were sedated with midazolam (5?mg)?+?Propofol (2?mg/kg i.v.). The Heliosphere Bag was air-filled with 950?ml while BIB? was inflated with 500?ml of saline and 10?ml of methylene blue. Percentage of excess weight loss (%EWL) and body mass index (BMI) were evaluated. Student t test, Fisher exact test, and ?? 2 test were used for statistical analysis.

Results

Similar weight loss parameters were observed in patients treated with liquid or air-filled balloon at time of removal: mean BMI was 40.8?±?6.2 and 41.9?±?6.5(p?=?ns), and mean %EWL was 20?±?12 and 18?±?14 (p?=?ns) in groups A and B, respectively. Significant longer extraction time, with high patient discomfort, was observed in group B due to difficult passage through the cardia and the lower pharynx.

Conclusions

Air-filled balloon can be another valid therapeutic option in the temporary treatment of obesity, but at this time, the quality of the device must be improved to ameliorate the patient compliance at removal and avoid the spontaneous deflations.  相似文献   
110.

Background

Five percent of all patients with breast cancer have distant metastatic disease at initial presentation. Because metastatic breast cancer is considered to be an incurable disease, it is generally treated with a palliative intent. Recent non-randomized studies have demonstrated that (complete) resection of the primary tumor is associated with a significant improvement of the survival of patients with primary metastatic breast cancer. However, other studies have suggested that the claimed survival benefit by surgery may be caused by selection bias. Therefore, a randomized controlled trial will be performed to assess whether breast surgery in patients with primary distant metastatic breast cancer will improve the prognosis.

Design

Randomization will take place after the diagnosis of primary distant metastatic breast cancer. Patients will either be randomized to up front surgery of the breast tumor followed by systemic therapy or to systemic therapy, followed by delayed local treatment of the breast tumor if clinically indicated. Patients with primary distant metastatic breast cancer, with no prior treatment of the breast cancer, who are 18 years or older and fit enough to undergo surgery and systemic therapy are eligible. Important exclusion criteria are: prior invasive breast cancer, surgical treatment or radiotherapy of this breast tumor before randomization, irresectable T4 tumor and synchronous bilateral breast cancer. The primary endpoint is 2-year survival. Quality of life and local tumor control are among the secondary endpoints. Based on the results of prior research it was calculated that 258 patients are needed in each treatment arm, assuming a power of 80%. Total accrual time is expected to take 60 months. An interim analysis will be performed to assess any clinically significant safety concerns and to determine whether there is evidence that up front surgery is clinically or statistically inferior to systemic therapy with respect to the primary endpoint.

Discussion

The SUBMIT study is a randomized controlled trial that will provide evidence on whether or not surgery of the primary tumor in breast cancer patients with metastatic disease at initial presentation results in an improved survival.

Trial registration

NCT01392586.  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