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   22419篇
  免费   2010篇
  国内免费   1742篇
耳鼻咽喉   159篇
儿科学   192篇
妇产科学   204篇
基础医学   2631篇
口腔科学   322篇
临床医学   3077篇
内科学   3309篇
皮肤病学   250篇
神经病学   1066篇
特种医学   762篇
外国民族医学   16篇
外科学   2345篇
综合类   4059篇
现状与发展   4篇
一般理论   1篇
预防医学   1301篇
眼科学   718篇
药学   2505篇
  27篇
中国医学   1234篇
肿瘤学   1989篇
  2024年   134篇
  2023年   406篇
  2022年   1061篇
  2021年   1211篇
  2020年   958篇
  2019年   711篇
  2018年   763篇
  2017年   787篇
  2016年   693篇
  2015年   1080篇
  2014年   1322篇
  2013年   1139篇
  2012年   1708篇
  2011年   1787篇
  2010年   1099篇
  2009年   830篇
  2008年   1137篇
  2007年   1106篇
  2006年   1164篇
  2005年   992篇
  2004年   741篇
  2003年   709篇
  2002年   622篇
  2001年   497篇
  2000年   571篇
  1999年   554篇
  1998年   379篇
  1997年   321篇
  1996年   229篇
  1995年   229篇
  1994年   223篇
  1993年   119篇
  1992年   149篇
  1991年   149篇
  1990年   94篇
  1989年   100篇
  1988年   81篇
  1987年   90篇
  1986年   66篇
  1985年   42篇
  1984年   42篇
  1983年   28篇
  1982年   19篇
  1981年   10篇
  1980年   7篇
  1979年   12篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
曾毅 《安徽医学》2006,27(5):364-365
目的探讨血脂水平与脑梗死的关系。方法通过对137例急性脑梗死患者与对照组血脂变化观察,多因素分析用SPSS10.0软件包中的Logistic回归方程,计算相对危险度(RR),RR的95%可信限(CI)。结果脑梗死组TC、TG、LDL-C浓度均明显高于对照组,而HDL-C浓度明显低于对照组。结论血清TC>6.0mmol/L才增加脑梗死的风险,而HDL-C浓度≥0.85mmol/L可降低脑梗死的风险。  相似文献   
62.
63.
模拟生物矿化制备多糖铁的新方法   总被引:7,自引:0,他引:7  
目的建立模拟生物矿化制备多糖铁的新方法.方法选用壳聚糖,与FeCl3制成复合膜,模拟铁矿化过程,制备多糖铁.结果多糖铁为β-FeOOH晶形,且为纳米级.结论为开发补铁药提供了新途径,丰富和发展了纳米药学理论.  相似文献   
64.
陈怀生  龙波  梁玉佳  陈玉成  曾智 《中药材》2005,28(10):903-906
目的:观察兔髂动脉损伤后,丹参酮ⅡA治疗组中膜平滑肌细胞(SMC)周围胶原变化的趋势.方法:取体重2.5~3kg纯种雄性新西兰大白兔30只,球囊导管扩张法制作左髂动脉内膜球囊损伤模型,术后分配到治疗组和对照组.治疗组丹参酮ⅡA稀释静脉注射,疗程6天;对照组采用等量生理盐水静脉注射.术后7天、14天和28天处死实验兔,将左侧髂动脉取出制作石蜡切片,并作胶原染色.结论:术后7天治疗组和对照组胶原纤维染色均不明显,术后14天和28天对照组SMCs周围可见胶原染色阳性,红染增多;治疗组14天SMCs周围也可见红染增多,但28天红染不明显;两组差异以术后28天明显(P=0.017);胶原染色随时间变化的趋势有统计学意义(P=0.005).结论:丹参酮ⅡA有抑制血管损伤后细胞外基质堆积的作用,从而可能有防治术后再狭窄的效应.  相似文献   
65.
ObjectivesIn geriatric acetabular fractures, the quadrilateral surface (QLS) was frequently involved in acetabular fracture patterns and accompanied by medial displacement. It was important to buttress the medial displaced QLS and reconstruct the congruity of the affected acetabulum. To evaluate the clinical effectiveness of the novel infra‐pectineal quadrilateral surface buttress plates for the treatment of geriatric acetabular fractures.MethodsTwenty‐three geriatric patients who were treated for acetabular fractures involving QLS with the novel infra‐pectineal buttress plates (NIBP) through a single supra‐ilioinguinal approach between January 2015 and June 2019 were retrospectively analyzed; all patients received at least 1 year''s follow‐up. All patients were aged ≥60 years old and including 18 males and five females. Radiologic and clinical outcomes of patients involved in the study were collated and analyzed according to the Matta scoring system and the Merle D''Aubigné–Postel scoring system. The functional recovery scoring was compared using q‐test.ResultsAll 23 consecutive patients had relatively satisfactory clinical treatment effectiveness. Average ages, length of incision, operation time, and intraoperative blood loss were 69.8 ± 6.1 years, 12.1 ± 2.6 cm, 166.5 ± 43.5 min, and 500 (500,700) ml, respectively. According to the Matta scoring system, 14 cases of reduction were graded as excellent, five as good, and four as fair. At the last follow‐up, the clinical outcome evaluation was excellent in 13 cases, good in seven cases, and poor in three cases with the use of the Merle D''Aubigné–Postel scoring system. The difference of modified Merle D''Aubigne‐Postel score at 3 months, 6 months and last follow up was statistically significant (F = 21.56, p < 0.05). Postoperative lateral femoral cutaneous nerve injury occurred in three patients and heterotopic ossification occurred in one patient.ConclusionsFor the treatment of geriatric acetabular fractures, the NIBP could provide stable and effective fixation to the QLS involved acetabular fractures, and related satisfactory clinical results with few complications were noted.  相似文献   
66.
ObjectiveThe postoperative role of adjuvant radiotherapy in non-metastatic head and neck adenoid cystic carcinoma (ACC) remains controversial. We analyzed adjuvant radiotherapy’s effect on surgical patient survival.MethodsPatients diagnosed with ACC from 2004 to 2015 in the Surveillance, Epidemiology, and End Results database were analyzed. The overall survival (OS) and disease-specific survival (DSS) of patients after adjuvant radiotherapy were assessed using the Kaplan–Meier and multivariate Cox methods. Propensity score matching (PSM) was performed to adjust confounders between patients with or without adjuvant radiotherapy; a forest plot was generated by subgroup analysis.ResultsThe study included 742 patients. In the PSM cohort, adjuvant radiotherapy did not improve OS or DSS. Radiotherapy was not a protective factor for OS or DSS in the univariate and multivariate Cox proportional hazard models. In the subgroup analysis, postoperative radiotherapy improved the OS of female and N1-stage patients and those with oropharyngeal tumors or over 79 years and the DSS of N1-stage patients.ConclusionsPostoperative radiotherapy showed different benefits in ACC patients, and postoperative radiotherapy recommendations should be individualized. Female and N1-stage ACC patients and those with oropharyngeal tumors or patients over 79 years without distant metastases postoperatively could benefit from adjuvant radiotherapy.  相似文献   
67.
系统性硬化病是一种罕见的自身免疫病,可累及多器官系统,以免疫紊乱、血管损伤及过度纤维化沉积为主要特点。该病发病机制未完全阐明,尚缺乏特效药物来阻断疾病进展。间充质干细胞是一种具有低免疫源性、多向分化潜力、免疫调节及改善微环境等多种特性的细胞群,其在自身免疫病中的应用前景广受关注。目前,已有多项应用间充质干细胞治疗系统性...  相似文献   
68.
Porcine epidemic diarrhea (PED), characterized by diarrhea, vomiting, and dehydration, is an acute enteric infectious disease of pigs. The disease is caused by porcine epidemic diarrhea virus (PEDV), which infects the intestinal mucosal surface. Therefore, mucosal immunization through the oral route is an effective method of immunization. Lactic acid bacteria, which are acid resistant and bile-salt resistant and improve mucosal immunity, are ideal carriers for oral vaccines. The S1 glycoprotein of PEDV mediates binding of the virus with cell receptors and induces neutralizing antibodies against the virus. Therefore, we reversely screened the recombinant strain pPG-SD-S1/Δupp ATCC 393 expressing PEDV S1 glycoprotein by Lactobacillus casei deficient in upp genotype (Δupp ATCC 393). Mice were orally immunized three times with the recombinant bacteria that had been identified for expression, and the changes of anti-PEDV IgG and secreted immunoglobulin A levels were observed over 70 days. The results indicated that the antibody levels notably increased after oral administration of recombinant bacteria. The detection of extracellular cytokines on the 42nd day after immunization indicated high levels of humoral and cellular immune responses in mice. The above results demonstrate that pPG-SD-S1/Δupp ATCC 393 has great potential as an oral vaccine against PEDV.  相似文献   
69.
In this paper, the phase structure, composition distribution, grain morphology, and hardness of Al6061 alloy samples made with additive friction stir deposition (AFS-D) were examined. A nearly symmetrical layer-by-layer structure was observed in the cross section (vertical with respect to the fabrication-tool traversing direction) of the as-deposited Al6061 alloy samples made with a back-and-forth AFS-D strategy. Equiaxed grains were observed in the region underneath the fabrication tool, while elongated grains were seen in the “flash region” along the mass flow direction. No clear grain size variance was discovered along the AFS-D build direction except for the last deposited layer. Grains were significantly refined from the feedstock (~163.5 µm) to as-deposited Al6061 alloy parts (~8.5 µm). The hardness of the as-fabricated Al6061 alloy was lower than those of the feedstock and their heat-treated counterparts, which was ascribed to the decreased precipitate content and enlarged precipitate size.  相似文献   
70.
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