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   28311篇
  免费   3307篇
  国内免费   2063篇
耳鼻咽喉   457篇
儿科学   307篇
妇产科学   179篇
基础医学   2610篇
口腔科学   456篇
临床医学   3709篇
内科学   3296篇
皮肤病学   501篇
神经病学   1226篇
特种医学   1150篇
外国民族医学   6篇
外科学   2751篇
综合类   6357篇
现状与发展   11篇
一般理论   1篇
预防医学   2517篇
眼科学   601篇
药学   3179篇
  47篇
中国医学   2251篇
肿瘤学   2069篇
  2025年   8篇
  2024年   492篇
  2023年   647篇
  2022年   1390篇
  2021年   1673篇
  2020年   1430篇
  2019年   989篇
  2018年   1119篇
  2017年   1112篇
  2016年   942篇
  2015年   1502篇
  2014年   1864篇
  2013年   1925篇
  2012年   2496篇
  2011年   2699篇
  2010年   1982篇
  2009年   1663篇
  2008年   1736篇
  2007年   1614篇
  2006年   1385篇
  2005年   1156篇
  2004年   782篇
  2003年   742篇
  2002年   523篇
  2001年   406篇
  2000年   327篇
  1999年   219篇
  1998年   128篇
  1997年   124篇
  1996年   104篇
  1995年   90篇
  1994年   69篇
  1993年   44篇
  1992年   51篇
  1991年   41篇
  1990年   29篇
  1989年   42篇
  1988年   27篇
  1987年   26篇
  1986年   23篇
  1985年   22篇
  1984年   22篇
  1983年   3篇
  1982年   1篇
  1981年   6篇
  1980年   1篇
  1979年   3篇
  1978年   1篇
  1975年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
Severe fever with thrombocytopenia syndrome virus (SFTSV) is a tickborne bandavirus mainly transmitted by Haemaphysalis longicornis ticks in East Asia, mostly in rural areas. As of April 2022, the amplifying host involved in the natural transmission of SFTSV remained unidentified. Our epidemiologic field survey conducted in endemic areas in China showed that hedgehogs were widely distributed, had heavy tick infestations, and had high SFTSV seroprevalence and RNA prevalence. After experimental infection of Erinaceus amurensis and Atelerix albiventris hedgehogs with SFTSV, we detected robust but transitory viremias that lasted for 9–11 days. We completed the SFTSV transmission cycle between hedgehogs and nymph and adult H. longicornis ticks under laboratory conditions with 100% efficiency. Furthermore, naive H. longicornis ticks could be infected by SFTSV-positive ticks co-feeding on naive hedgehogs; we confirmed transstadial transmission of SFTSV. Our study suggests that the hedgehogs are a notable wildlife amplifying host of SFTSV in China.  相似文献   
103.
Background: The nutritional risk index (NRI) is an independent prognostic factor for overall survival in various cancers, but its prognostic value in breast cancer remains unclear. This study aimed to explore the relationship between the NRI and overall survival (OS) in breast cancer and to develop a predictive nomogram. Methods: We retrospectively enrolled 1347 breast cancer patients who underwent mastectomy or lumpectomy between January 2011 and November 2012. Using a cutoff value of 110.59, patients were divided into a high-NRI group and a low-NRI group. OS was compared between the two groups. Clinicopathological factors independently associated with survival were used to construct a predictive nomogram. Results: Of the 1347 patients, 534 patients were classified as high NRI and 813 as low NRI. OS was significantly shorter in low-NRI patients. The 3- and 5-year OS rates were 87.3% and 73.4%, respectively, in the high-NRI group whereas they were 83.0% and 67.2%, respectively, in the low-NRI group. Cox regression analysis found that histopathological type, tumor size, lymph node status, progesterone receptor (PR) status, Ki-67, and NRI were independently associated with OS. Conclusions: NRI is an independent prognostic factor of OS in breast cancer patients. The proposed nomogram model may be a useful tool for individualized survival prediction.  相似文献   
104.
胡菲  谢晓华 《口腔医学》2021,41(7):644-648
骨形态发生蛋白1(bone morphogenetic protein 1,BMP1)和哺乳动物tolloid样1(mammalian tolloid-like 1,mTLL1)是细胞外基质金属蛋白酶,同属于虾红素家族(astacin family),在包括牙在内的多种组织中共表达.BMP1和mTLL1具有功能冗余性,...  相似文献   
105.
Background and ObjectivesAromatase inhibitors (AIs) provide an alternative to tamoxifen as an adjuvant therapy for postmenopausal patients with breast cancer (BC). Large trials resulted better outcomes with AIs. Adjuvant therapy with AIs reduced the risk of relapse compared with tamoxifen. Systemic therapies for BC can interfere with bone turnover, either by affecting gonadal steroid hormone production or by inhibiting peripheral aromatization into estrogen. We aimed to evaluate the safety profile of bone-related events by comparing 3 AIs with tamoxifen and a placebo.MethodsThe Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines were used for network meta-analyses (NMAs). Searches were performed using PubMed, Embase/Medline, Cochrane, and Ovid databases. Randomized controlled trials comparing tamoxifen and placebo or other AIs to steroidal or nonsteroidal AIs in patients with BC reporting bone-related safety events were included in NMA. NMA in a Bayesian approach was performed using R software (ver 3.2), Gemtc package.ResultsSeventeen studies reporting 4 different bone-related endpoints were included. Although there was no statistical significance, treatment with exemestane lowered the incidence of bone pain (odds ratio [OR] vs. anastrozole and letrozole: 0.63, 0.54), fracture episodes (OR vs. anastrozole and letrozole: 0.84, 0.80), and osteoporosis (OR vs. anastrozole and letrozole: 0.85, 0.73) compared with letrozole and anastrozole. Reduction in bone mineral density was lesser in exemestane than in anastrozole (mean reduction in hip: 1.05; lumbar spine: 1.25). Treatment ranking with the surface under the cumulative ranking curve showed that exemestane was found to reduce the incidence of bone-related adverse events.ConclusionA lower incidence of bone-related safety events was observed in patients treated with exemestane.  相似文献   
106.
ObjectiveAdequacy of decompression for oblique lateral interbody fusion (OLIF) is a real concern in patients with severe lumbar spinal stenosis (LSS). With this in mind, we combined OLIF with spinal endoscopic technique to achieve a solid fusion and an adequate decompression after one operation.MethodsThis is a technical note. The theoretical basis and operation process of this technique were introduced, and consecutive cases were retrospectively collected. Consecutive patients diagnosed with monosegmental severe LSS (L4/5) and underwent oblique lateral endoscopic decompression and interbody fusion (OLEDIF) from January 2018 to February 2020 were retrospectively collected. Clinical outcomes were assessed by claudication distance, Visual Analog Scale (VAS), and Oswestry Disability Index (ODI) scores. Secondary indicators included operation time, operative blood loss, and postoperative complications.ResultsTen patients were selected for the OLEDIF procedure. They were five women and five men ranging in age from 49 to 75 years (mean age of 63.9 years) and in BMI from 25.4 to 30.2 kg/m2 (mean BMI of 27.5 kg/m2). The preoperative claudication distance was 160.00 ± 68.96 m (range 70–250 m), which was significantly extended on the 3‐month and 1‐year follow‐up (1020.00 ± 407.70 m and 1040.00 ± 416.87 m, respectively). The preoperative VAS score of back pain and radiating leg pain was 5.50 ± 0.97 (range 4–7) and 6.40 ± 0.97 (range 5–8). The score on postoperative month 3 was 1.60 ± 0.52 (range 1–2) and 1.20 ± 0.79 (range 0–2), and the 1‐year follow‐up score was 1.90 ± 0.74 (range 1–3) and 1.60 ± 0.70 (range 1–3), respectively. The preoperative ODI was 72.23 ± 6.30 (range 64.4–82.2), the 3‐month follow‐up ODI was 31.12 ± 4.20 (range 24.4–35.6), and the 1‐year follow‐up ODI was 29.33 ± 5.92 (range 20.0–37.8). Compared with the transforaminal lumbar interbody fusion (TLIF) in the literature, the operation time was not prolonged (189.3 ± 32.5 min vs. 214.9 ± 60.0 min) but the amount of blood loss decreased significantly (113.3 ± 26.7 ml vs. 366.8 ± 298.2 ml). No complications were found except one case presented with dysesthesia of the left leg. Imaging results showed good fusion without cage subsidence during 1‐year follow‐up.ConclusionOLEDIF can achieve complete ventral decompression of the spinal canal and solid fusion of the lumbar spine at one time. It is an effective minimally invasive technique for the treatment of monosegmental severe LSS, which is promising and worthy of further clinical practice.  相似文献   
107.
It remains challenging to determine the regions of metastasis to lymph nodes during operation for clinical stage I non-small cell lung cancer (NSCLC). This study aimed to establish intraoperative mathematical models with nomograms for predicting the hilar-intrapulmonary node metastasis (HNM) and the mediastinal node metastasis (MNM) in patients with clinical stage I NSCLC. The clinicopathological variables of 585 patients in a derivation cohort who underwent thoracoscopic lobectomy with complete lymph node dissection were retrospectively analyzed for their association with the HNM or the MNM. After analyzing the variables, we developed multivariable logistic models with nomograms to estimate the risk of lymph node metastasis in different regions. The predictive efficacy was then validated in a validation cohort of 418 patients. It was confirmed that carcinoembryonic antigen (>5.75 ng/mL), CYFRA211 (>2.85 ng/mL), the maximum diameter of tumor (>2.75 cm), tumor differentiation (grade III), bronchial mucosa and cartilage invasion, and vascular invasion were predictors of HNM, and carcinoembryonic antigen (>8.25 ng/mL), CYFRA211 (>2.95 ng/mL), the maximum diameter of tumor (>2.75 cm), tumor differentiation (grade III), bronchial mucosa and cartilage invasion, vascular invasion, and visceral pleural invasion were predictors of MNM. The validation of the prediction models based on the above results demonstrated good discriminatory power. Our predictive models are helpful in the decision-making process of specific therapeutic strategies for the regional lymph node metastasis in patients with clinical stage I NSCLC.  相似文献   
108.
109.
110.
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