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   6343篇
  免费   540篇
  国内免费   12篇
耳鼻咽喉   50篇
儿科学   131篇
妇产科学   81篇
基础医学   913篇
口腔科学   111篇
临床医学   862篇
内科学   1346篇
皮肤病学   134篇
神经病学   424篇
特种医学   220篇
外国民族医学   1篇
外科学   825篇
综合类   41篇
预防医学   589篇
眼科学   210篇
药学   507篇
中国医学   39篇
肿瘤学   411篇
  2024年   8篇
  2023年   93篇
  2022年   210篇
  2021年   394篇
  2020年   216篇
  2019年   256篇
  2018年   227篇
  2017年   181篇
  2016年   198篇
  2015年   198篇
  2014年   248篇
  2013年   275篇
  2012年   455篇
  2011年   455篇
  2010年   237篇
  2009年   240篇
  2008年   385篇
  2007年   401篇
  2006年   326篇
  2005年   310篇
  2004年   256篇
  2003年   213篇
  2002年   159篇
  2001年   146篇
  2000年   130篇
  1999年   113篇
  1998年   48篇
  1997年   45篇
  1996年   26篇
  1995年   23篇
  1994年   26篇
  1993年   21篇
  1992年   58篇
  1991年   40篇
  1990年   27篇
  1989年   57篇
  1988年   24篇
  1987年   32篇
  1986年   23篇
  1985年   24篇
  1984年   11篇
  1983年   14篇
  1982年   7篇
  1981年   13篇
  1980年   5篇
  1979年   11篇
  1978年   5篇
  1977年   5篇
  1975年   4篇
  1974年   7篇
排序方式: 共有6895条查询结果,搜索用时 29 毫秒
991.
992.
993.

Background

Metastases to the brain occur in 10%-16% of patients with breast cancer, with incidence reportedly increasing. Historically, brain metastases (BM) have been treated with whole-brain radiation therapy (WBRT), but stereotactic radiosurgery (SRS) is an increasingly favored treatment option. In this study we used a population-level database to compare patterns of care and survival between WBRT and SRS for BM from breast cancer.

Materials and Methods

The National Cancer Database was used to select patients treated with radiation for BM from primary breast cancer. Groups were classified on the basis of the modality of radiation delivered to the brain and compared across several demographic factors. A Kaplan–Meier survival curve and Cox multivariate analysis were used to compare overall survival. A matched analysis using propensity scores was used to further reduce confounders and compare survival.

Results

The treatment groups were significantly different across several socioeconomic variables including income, insurance status, and treatment setting. The percentage of patients who received SRS increased dramatically in the second half of the analyzed time period (P < .001). Unadjusted median survival was significantly longer for patients who received SRS versus those who received WBRT (P < .001). This finding persisted after propensity score-matching.

Conclusion

Receipt of SRS was associated with different socioeconomic variables and longer overall survival compared with WBRT, highlighting the need for less toxic treatment for patients who are now living longer. The results revealed important socioeconomic differences between patients selected for SRS versus WBRT and emphasizes disparities in access to modern radiation techniques across the United States.  相似文献   
994.
995.
Objectives

Prosthetic joint infections (PJI) and especially tuberculosis (TB) PJI are rare diseases and hard to cure. The effectiveness of treatments for tuberculous PJI still remains a problem. The objective of this research was to indicate the success of two-stage revision replacement and also giving the associated criteria.

Methods

From 2015 to 2020, five patients with tuberculous PJI were treated with two-stage revision at Cho Ray hospital, Vietnam. We collected the dataset which included demographic data, the interval from the time of joint replacement to reported infection, records of tuberculous PJI, administration of anti-TB medications (duration, months), history of operation(s), duration of follow-up, and specific type(s) of antibiotics loaded in bone cement. The approval for this study was made by the institutional review board from Cho Ray Hospital, Vietnam. We conducted a literature review based on the keywords “PJI” and “TB” on PubMed.

Results

Five patients [median age 66 years (range 35–84)] had found tuberculous PJI. The median time from arthroplasty to diagnosis was 19 months (range 4–48). The diagnosis was confirmed by joint aspirates or synovial tissue. Positive PCR was also reported in all cases. The average duration of anti-tuberculosis polytherapy administration was 14.4 months. The operative techniques on five patients included debridement and using spacer loaded with 2 g streptomycin (and 2 g vancomycin if they got a coinfection) for 1 pack of bone cement, and revision arthroplasty. In most cases, the outcome of treatment using two-stage revision replacement was 80%. Overall, the auxiliary bacterial infections were recognized in three patients with tuberculous PJI and Staphylococcus aureus. Streptomycin and vancomycin were loaded in a cement spacer to increase the success rate, and tuberculous PJI was controlled for all patients.

Conclusion

Tuberculous PJI can be controlled with two-stage revision replacement with an antibiotic-loaded cement spacer that is molded intraoperatively with custom mold and prolonged anti-tuberculosis treatment in all cases.

Level of evidence

IV.

  相似文献   
996.
997.
998.
T. Godel  M. Pham 《Der Radiologe》2018,58(11):1004-1010

Clinical/methodical issue

Entrapment syndromes of peripheral nerves at the elbow are common and are often diagnostically challenging disorders. Difficulties consist in lesion localization and recognition of complex spatial lesion patterns as well as in differentiation of focal and multifocal disorders.

Standard diagnostic methods

Medical history taking, neurological examination and neurophysiological tests represent the gold standard in the diagnosis of peripheral nerve lesions at the elbow, but have known methodical limitations.

Methodical innovations

Additional diagnostic imaging tools recently developed for high-resolution visualization of extended peripheral nerve segments include 3?T magnetic resonance neurography (MRN) and neurosonography.

Performance

MRN and neurosonography can directly visualize and thus precisely localize focal and nonfocal peripheral nerve lesions of various origins with high spatial resolution at the anatomical level of nerve fascicles.

Achievements

MRN can cover peripheral nerve structures at the elbow, evaluate spatial nerve lesion patterns and partly disclose underlying causes.

Practical recommendations

Imaging of peripheral nerves is a valuable addition in the diagnostic work-up of entrapment syndromes at the elbow and provides important assistance in the differentiation of nonfocal differential diagnoses, especially in cases that cannot be clarified using standard diagnostic methods. The evaluation of spatial nerve lesion pattern may give additional information on the origin of the underlying disease, which is essential for further treatment.
  相似文献   
999.
The efficacy of cisplatin (CIS) and 5-fluorouracil (5-FU) against squamous cell carcinomas of the head and neck (SCCHN) remains restricted due to their severe toxic side effects on non-cancer (normal) tissues. Recently, the broccoli extract sulforaphane (SF) was successfully tested as a combination therapy to target cancer cells. However, the effect of lower doses of CIS or 5-FU combined with SF on SCCHN remained unknown. This study tested the chemotherapeutic efficacies of SF combined with much lower doses of CIS or 5-FU against SCCHN cells aiming to reduce cytotoxicity to normal cells. Titrations of SF standalone or in combination with CIS and 5-FU were tested on SCCHN human cell lines (SCC12 and SCC38) and non-cancerous human cells (fibroblasts, gingival, and salivary cells). Concentrations of SF tested were comparable to those found in the plasma following ingestion of fresh broccoli sprouts. The treatment effects on cell viability, proliferation, DNA damage, apoptosis, and gene expression were measured. SF reduced SCCHN cell viability in a time- and dose-dependent manner. SF-combined treatment increased the cytotoxic activity of CIS by twofolds and of 5-FU by tenfolds against SCCHN, with no effect on non-cancerous cells. SF-combined treatment inhibited SCCHN cell clonogenicity and post-treatment DNA repair. SF increased SCCHN apoptosis and this mechanism was due to a down-regulation of BCL2 and up-regulation of BAX, leading to an up-regulation of Caspase3. In conclusion, combining SF with low doses of CIS or 5-FU increased cytotoxicity against SCCHN cells, while having minimal effects on normal cells.  相似文献   
1000.
  1. The progressive motor neuronopathy (pmn) mouse is an autosomal recessive mutant, in which the homozygotes suffer caudio-cranial degeneration of motor axons and die several weeks after birth. This strain provides the opportunity of testing potential therapeutic strategies for the treatment of motor neurone diseases such as amyotrophic lateral sclerosis. We have performed a study of the effects on the pmn mouse of SR 57746A, an orally-active, non-peptide compound which has been found to exhibit neurotrophic effects in vitro and in vivo. In order to treat the affected mice from birth, the mothers were administered 2.5 mg kg−1, p.o., SR 57746A every two days until the weaning of the offspring (at day 20); then the offspring were given every two days a dose of 30 μg kg−1, p.o., until their death.
  2. Affected mice treated with SR 57746A had a lifespan 50% longer than that of the vehicle-treated mice (P=0.01). Compared to vehicle-treated pmn mice, SR 57746A improved the performance of the pmn mice in three different behavioural tasks. SR 57746A also maintained the amplitude of the motor evoked response of the gastrocnemius muscle, reduced the distal motor latency, and delayed the occurrence of the spontaneous denervation activity in this muscle. Histological studies indicated that at 20 days of age the mean surface areas of the fibres of the sciatic nerve were higher in SR 57746A-treated than in vehicle-treated mice.
  3. At present, SR 57746A is the only orally active, nonpeptide compound known to be capable of delaying the progression of the motor neurone degeneration in pmn mice.
  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