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   14047篇
  免费   1236篇
  国内免费   25篇
耳鼻咽喉   219篇
儿科学   561篇
妇产科学   379篇
基础医学   1694篇
口腔科学   171篇
临床医学   1562篇
内科学   2472篇
皮肤病学   258篇
神经病学   1561篇
特种医学   303篇
外科学   1634篇
综合类   132篇
一般理论   21篇
预防医学   2212篇
眼科学   326篇
药学   832篇
  1篇
中国医学   15篇
肿瘤学   955篇
  2024年   37篇
  2023年   288篇
  2022年   468篇
  2021年   931篇
  2020年   539篇
  2019年   791篇
  2018年   858篇
  2017年   576篇
  2016年   594篇
  2015年   576篇
  2014年   725篇
  2013年   885篇
  2012年   1278篇
  2011年   1254篇
  2010年   612篇
  2009年   491篇
  2008年   807篇
  2007年   746篇
  2006年   573篇
  2005年   537篇
  2004年   431篇
  2003年   348篇
  2002年   267篇
  2001年   48篇
  2000年   39篇
  1999年   51篇
  1998年   46篇
  1997年   33篇
  1996年   28篇
  1995年   26篇
  1994年   26篇
  1993年   31篇
  1992年   29篇
  1991年   22篇
  1990年   13篇
  1989年   19篇
  1987年   11篇
  1985年   20篇
  1984年   20篇
  1983年   11篇
  1982年   22篇
  1981年   14篇
  1980年   11篇
  1979年   19篇
  1978年   13篇
  1977年   10篇
  1976年   13篇
  1974年   9篇
  1972年   11篇
  1970年   9篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
BackgroundIn counseling patients about the complications of revision total hip arthroplasty (revTHA), it is imperative that mortality be considered. The actual mortality rate by indication of revision is ill-defined. The purpose of this study is to determine the mortality rate after revTHA.MethodsAn institutional database identified 596 patients who had undergone revTHA between 2012 and 2018. Medical records, national, state, and local death indexes were queried for mortality status and indication for revTHA. For survivors, the last clinical visit date was used for censoring in the mortality analysis. Mortality rates were calculated for all clinical patients and then by specific indication for revision.ResultsThe overall 2-year mortality rate following revTHA was 19.5 deaths per 1000 or 1 in 51 patients. Patients presenting with a periprosthetic fracture had a significantly higher 2-year mortality rate of 74.5 deaths per 1000 or 1 in 13 patients (P < .001), while an indication of dislocation or instability had a slightly higher 2-year mortality rate of 50.3 per 1000 (1 in 20) but this difference was not significant (P = .531). Other indications such as mechanical loosening or infection did not have a significantly different mortality rate.ConclusionThe overall 2-year mortality rate following revTHA was 19.5 deaths per 1000 which was largely attributed to patients with a periprosthetic fracture (74.5 per 1000) with other indications not significantly impacting mortality. Mortality rates and specific rates by indication for revision should be considered when counseling patients prior to revTHA.  相似文献   
93.
Background/purposeThough evidence-based clinical pathways for the diagnosis and treatment of pediatric appendicitis have been established, protocols guiding management of percutaneous abscess drains are lacking. We hypothesized a drain management protocol utilizing drain output and clinical factors instead of fluoroscopic drain studies would reduce interventional radiologic procedures without adversely impacting clinical outcomes.MethodsA standardized protocol was uniformly adopted at a tertiary-care children's hospital in April 2016. A retrospective chart review included all cases of appendicitis requiring abscess drainage by interventional radiology three years pre- and postprotocol implementation.ResultsFifty-eight patients (preprotocol = 39, postprotocol = 19) underwent percutaneous abscess drainage, of whom 52 (preprotocol = 34, postprotocol = 18) required a drain. Baseline demographics and clinical presentation were similar across groups. Following protocol implementation, total number of IR procedures decreased from 2.4 to 1.3 per patient (p = 0.004). There was no significant difference in the number of postprocedure diagnostic imaging studies, readmissions, or inpatient days, and there was a trend towards a decrease in number of drain days (10.7 to 5.7, p = 0.067).ConclusionA standardized protocol for management of abscess drains for complicated appendicitis reduced the number of IR procedures without a negative impact on clinical outcomes or increase in alternative imaging studies. This approach may decrease radiation exposure, anesthetic administration, and resource utilization.Type of studyTreatment study (retrospective comparative study).Level of evidenceLevel III.  相似文献   
94.
Skeletal muscle has remarkable regenerative ability after injury. Mesenchymal fibro-adipogenic progenitors (FAPs) are necessary, active participants during this repair process, but the molecular signatures of these cells and their functional relevance remain largely unexplored. Here, using a lineage tracing mouse model (Gli1-CreER Tomato), we demonstrate that Gli1 marks a small subset of muscle-resident FAPs with elevated Hedgehog (Hh) signaling. Upon notexin muscle injury, these cells preferentially and rapidly expanded within FAPs. Ablation of Gli1+ cells using a DTA mouse model drastically reduced fibroblastic colony-forming unit (CFU-F) colonies generated by muscle cells and impaired muscle repair at 28 days. Pharmacologic manipulation revealed that Gli1+ FAPs rely on Hh signaling to increase the size of regenerating myofiber. Sorted Gli1+ FAPs displayed superior clonogenicity and reduced adipogenic differentiation ability in culture compared to sorted Gli1− FAPs. In a glycerol injury model, Gli1+ FAPs were less likely to give rise to muscle adipocytes compared to other FAPs. Further cell ablation and Hh activator/inhibitor treatments demonstrated their dual actions in enhancing myogenesis and reducing adipogenesis after injury. Examining single-cell RNA-sequencing dataset of FAPs from normal mice indicated that Gli1+ FAPs with increased Hh signaling provide trophic signals to myogenic cells while restrict their own adipogenic differentiation. Collectively, our findings identified a subpopulation of FAPs that play an essential role in skeletal muscle repair. © 2021 American Society for Bone and Mineral Research (ASBMR).  相似文献   
95.
Bone metastasis is a complication of prostate cancer in up to 90% of men afflicted with advanced disease. Therapies that reduce androgen exposure remain at the forefront of treatment. However, most prostate cancers transition to a state whereby reducing testicular androgen action becomes ineffective. A common mechanism of this transition is intratumoral production of testosterone (T) using the adrenal androgen precursor dehydroepiandrosterone (DHEA) through enzymatic conversion by 3β- and 17β-hydroxysteroid dehydrogenases (3βHSD and 17βHSD). Given the ability of prostate cancer to form blastic metastases in bone, we hypothesized that osteoblasts might be a source of androgen synthesis. RNA expression analyses of murine osteoblasts and human bone confirmed that at least one 3βHSD and 17βHSD enzyme isoform was expressed, suggesting that osteoblasts are capable of generating androgens from adrenal DHEA. Murine osteoblasts were treated with 100 nM and 1 μM DHEA or vehicle control. Conditioned media from these osteoblasts were assayed for intermediate and active androgens by liquid chromatography–tandem mass spectrometry. As DHEA was consumed, the androgen intermediates androstenediol and androstenedione were generated and subsequently converted to T. Conditioned media of DHEA-treated osteoblasts increased androgen receptor (AR) signaling, prostate-specific antigen (PSA) production, and cell numbers of the androgen-sensitive prostate cancer cell lines C4-2B and LNCaP. DHEA did not induce AR signaling in osteoblasts despite AR expression in this cell type. We describe an unreported function of osteoblasts as a source of T that is especially relevant during androgen-responsive metastatic prostate cancer invasion into bone. © 2021 American Society for Bone and Mineral Research (ASBMR). This article has been contributed to by US Government employees and their work is in the public domain in the USA.  相似文献   
96.
97.
Background

Metaplastic breast carcinoma (MBC) is a rare, aggressive subtype of breast cancer associated with poorer overall survival than other triple-negative breast cancers. This study sought to compare survival outcomes among histologic subtypes of MBC with those of non-metaplastic triple-negative breast cancer.

Methods

Clinicopathologic and treatment data for all patients with non-metastatic, pure MBC undergoing surgery from 1995 to 2017 and for a large cohort of patients with other types of triple-negative breast cancer during that period were collected from an institutional database. The MBC tumors were classified as having squamous, spindle, heterologous mesenchymal, or mixed histology. Survival outcomes were compared using the Kaplan-Meier method.

Results

Of 132 MBC patients, those with heterologous mesenchymal MBC (n?=?45) had the best 5-year overall and breast cancer-specific survival (BCSS, 88%; 95% confidence interval [CI], 0.78–0.99), whereas those with squamous MBC had the worst survival (BCSS, 56%; 95% CI, 0.32–0.79). Overall survival, BCSS, and recurrence-free survival were worse for the patients with MBC than for the patients who had non-MBC triple-negative breast cancer, with a clinicopathologically adjusted recurrence hazard ratio of 2.4 (95% CI, 1.6–3.3; p?<?0.001). Of the 10 MBC patients who received neoadjuvant chemotherapy, 4 progressed while receiving treatment, and 3 had no response.

Conclusions

Metaplastic breast carcinoma is associated with worse survival than other triple-negative breast cancers. The heterologous mesenchymal subtype is associated with the best survival, whereas the squamous subtype is associated with the worst survival. These data call for research to identify therapies tailored to MBC’s unique biology.

  相似文献   
98.
Annals of Surgical Oncology - Black women with breast cancer have a worse overall survival compared with White women; however, no difference in Oncotype DX? (ODX) recurrence scores has been...  相似文献   
99.
BackgroundPreoperative carbohydrate loading is a component of Enhanced Recovery After Surgery (ERAS) protocols, but there is limited literature in bariatric surgery patients.ObjectivesThe objective of this study was to characterize the impact of preoperative carbohydrate loading on postoperative bariatric surgery outcomes.SettingUniversity Hospital.MethodsPatients undergoing a primary minimally invasive Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) between 2018 and 2020 were randomized to standard management or intervention. Standard management patients were nothing by mouth (NPO) after midnight prior to surgery. Intervention patients consumed 2 carbohydrate drinks: 1 the night before and another 3 hours prior to surgery. Primary outcomes analyzed included postoperative nausea and vomiting (PONV), length of stay, and overall complications.ResultsIn total, 134 patients were analyzed: 64 intervention (47.8%) and 70 (52.2%) standard. In the end, 7% and 15% of patients were lost to follow-up at 6-weeks and 3-months, respectively. There was no statistically significant difference in length of stay (2.0 ± 1.2 vs 2.1 ± .9 d; P = .65) or postoperative outcomes between the 2 groups. There were no episodes of aspiration among the intervention group. Among RYGB patients, intervention patients had a shorter duration of nausea compared with standard patients. There was no significant difference in glycemic control among patients with and without diabetes.ConclusionsPreoperative carbohydrate drinks can be administered to bariatric surgery patients without significant risks. Carbohydrate loading preoperatively can decrease the duration of PONV in RYGB patients. Carbohydrate drinks can be safely included in bariatric ERAS protocols for patients with and without diabetes, although the benefits remain unknown.  相似文献   
100.
Background: Hand and distal forearm allotransplantation has advanced over the last 20 years from experimental to a viable treatment option for bilateral upper extremity amputation. Despite widespread growth of this field, there are few technical reports that elaborate the details of donor arm procurement. This article details a technique for rapid donor procurement through the elbow for mid to distal forearm-level hand allograft procurement. Methods: Nine arm procurements were performed on deceased tissue-only donors provided by the local organ procurement organization, including two bilateral and five unilateral cases. Technique highlights include using a fishmouth incision through the lateral and medical epicondyles, identification of the neurovascular structures, and disarticulating the elbow joint. Results: Procuring through the elbow provides straightforward anatomy, bypasses the need to cut through bone, and allows tissue allotransplantation teams to achieve procurement, flushing, and packaging within 20 minutes. Conclusions: Procurement through the elbow is a simple procedure that streamlines the process for multi-organ donors by minimizing the time needed for hand allograft procurement. Team coordination and surgical rehearsals are essential for successful hand and upper extremity procurement and allotransplantation.  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