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   15490篇
  免费   821篇
  国内免费   73篇
耳鼻咽喉   131篇
儿科学   295篇
妇产科学   475篇
基础医学   1876篇
口腔科学   565篇
临床医学   1252篇
内科学   4378篇
皮肤病学   394篇
神经病学   1373篇
特种医学   317篇
外科学   2232篇
综合类   98篇
一般理论   2篇
预防医学   1113篇
眼科学   217篇
药学   845篇
中国医学   79篇
肿瘤学   742篇
  2024年   11篇
  2023年   160篇
  2022年   390篇
  2021年   652篇
  2020年   350篇
  2019年   532篇
  2018年   707篇
  2017年   410篇
  2016年   420篇
  2015年   481篇
  2014年   734篇
  2013年   842篇
  2012年   1326篇
  2011年   1335篇
  2010年   683篇
  2009年   612篇
  2008年   1023篇
  2007年   955篇
  2006年   908篇
  2005年   877篇
  2004年   767篇
  2003年   603篇
  2002年   604篇
  2001年   70篇
  2000年   71篇
  1999年   87篇
  1998年   93篇
  1997年   64篇
  1996年   73篇
  1995年   60篇
  1994年   46篇
  1993年   33篇
  1992年   38篇
  1991年   25篇
  1990年   23篇
  1989年   19篇
  1988年   19篇
  1987年   11篇
  1986年   27篇
  1985年   19篇
  1984年   22篇
  1983年   17篇
  1982年   23篇
  1981年   20篇
  1980年   22篇
  1979年   8篇
  1978年   12篇
  1974年   12篇
  1973年   20篇
  1972年   10篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
OBJECTIVE: Mounting evidence supports the view that intimate partner violence (IPV) is an important cause of maternal mortality. Some, but not all, prior studies suggest that IPV is associated with increased risks of maternal medical conditions such as hypertensive disorders of pregnancy which are leading causes of maternal mortality worldwide. We assessed the relation between IPV and risk of preeclampsia among Peruvian women. STUDY DESIGN: We conducted a case-control study at two large hospitals in Lima, Peru. Preeclampsia cases were 339 women with pregnancy-induced hypertension and proteinuria (i.e., preeclampsia). Controls were 337 normotensive women. Information concerning women's exposure to physical and emotional violence during pregnancy was collected during in-person interviews conducted after delivery and while patients were in hospital. Odds ratios (OR) and 95% confidence intervals (CI) were estimated from logistic regression models. RESULTS: The prevalence of IPV was 43.1% among cases and 24.3% among controls. Compared with those reporting never exposure to IPV during pregnancy, women reporting any exposure had a 2.4-fold increased risk of preeclampsia (OR=2.4; 95% CI: 1.7-3.3). The association was strengthened slightly after adjusting for maternal age, parity and pre-pregnancy adiposity (OR=2.7; 95% CI: 1.9-3.9). Emotional abuse in the absence of physical violence was associated with a 3.2-fold (95% CI: 2.1-4.9) increased risk of preeclampsia. Emotional and physical abuse during pregnancy was associated with a 1.9-fold increased risk of preeclampsia (95% CI: 1.1-3.5). CONCLUSIONS: IPV among pregnant women is common and is associated with an increased risk of preeclampsia. These data support recent calls for coordinated global health efforts to prevent violence against women.  相似文献   
93.

Background

The increasing role of robotic surgery in gynecologic oncology may impact fellowship training. The purpose of this study was to review the proportion of robotic procedures performed by fellows at the console, and compare operative times and lymph node yields to faculty surgeons.

Methods

A prospective database of women undergoing robotic gynecologic surgery has been maintained since 2008. Intra-operative datasheets completed include surgical times and primary surgeon at the console. Operative times were compared between faculty and fellows for simple hysterectomy (SH), bilateral salpingo-oophorectomy (BSO), pelvic (PLND) and paraaortic lymph node dissection (PALND) and vaginal cuff closure (VCC). Lymph nodes counts were also compared.

Results

Times were recorded for 239 SH, 43 BSOs, 105 right PLNDs, 104 left PLNDs, 34 PALND and 269 VCC. Comparing 2008 to 2011, procedures performed by the fellow significantly increased; SH 16% to 83% (p < 0.001), BSO 7% to 75% (p = 0.005), right PLND 4% to 44% (p < 0.001), left PLND 0% to 56% (p < 0.001), and VCC 59% to 82% (p = 0.024). Console times (min) were similar for SH (60 vs. 63, p = 0.73), BSO (48 vs. 43, p = 0.55), and VCC (20 vs. 22, p = 0.26). Faculty times (min) were shorter for PLND (right 26 vs. 30, p = 0.04, left 23 vs. 27, p = 0.02). Nodal counts were not significantly different (right 7 vs. 8, p = 0.17 or left 7 vs. 7, p = 0.87).

Conclusions

Robotic surgery can be successfully incorporated into gynecologic oncology fellowship training. With increased exposure to robotic surgery, fellows had similar operative times and lymph node yields as faculty surgeons.  相似文献   
94.

Objetive

: To know Spanish Obstetrics and Gynaecology Society (SEGO) members about cesarean section on request.

Method

Three questions appeared on SEGO web: 1) If a normal primigravid with a term, cephalic presentation foetus ask you for a caesarean section, would you do it?; 2) If a normal primigravid with a term, breach presentation foetus ask you for a caesarean section, would you do it?; 3) If a woman on her normal third pregnancy with two previous vaginal and with a term, breach presentation foetus ask you for a caesarean section, would you do it? Questions were asked in May 2006 and answers were collected 19th October 2006. Data analysis was processed with web page statistic method.

Results

Among the 5300 members of SEGO, 1222 contacted the web page (23%). To question n° 1, 57.8% answered no, 24.8% yes and 17.4% had no answer. To question n° 2, 6.1% answered no, 93.8% yes and there were no abstention. To n° 3 question, 16.7% said no, 74.5% said yes and 8.8% has no opinion.Results are commented, advantages and disadvantages of caesarean are discussed as well as sanitary consequences of such an indication.  相似文献   
95.
96.
97.
BackgroundBlood transfusion centres should understand the epidemiology of emerging diseases that are transmissible through the transfusion of blood components. The risk of transmission of arboviruses through this route has become apparent in recent years. The aim of our study is to summarise the reported prevalence (viraemic rate, seroprevalence and/or antigen detection) of Chikungunya (CHIKV), Dengue (DENV) and Zika (ZIKV) viruses in blood donors according to screening test used and world region.Materials and methodsWe conducted a systematic literature review and meta-analysis having searched for information in the main bibliographic databases (MEDLINE, Embase, and Scopus). The prevalence for each of the viruses was calculated according to the screening test used and geographic location.ResultsWe included 18 records on CHIKV, 71 on DENV, and 27 on ZIKV. The highest prevalences of RNA for CHIKV were 1.9% in Puerto Rico (2014), 1.0% in Thailand (2009), and 1.0% in French Polynesia (2014–15). The highest prevalences of RNA for DENV were 5.5% in Saudi Arabia (2015–16), 2.3% in Madeira, Portugal (2012–13), and 0.6% in Brazil (2012). The highest prevalences of RNA for ZIKV were 2.8% in French Polynesia (2013–14), 2.7% in Brazil (2015–16), and 1.8% in Martinique (2016). Overall seroprevalence, as assessed by IgG antibodies, was 21.6% for CHIKV, 24.0% for DENV, and 5.1% for ZIKV.DiscussionOur study shows a high proportion of donors who are viraemic and asymptomatic, especially during outbreaks, with prevalences surpassing 5% for DENV, 1% for CHIKV, and 2% for ZIKV. These data confirm a clear threat to blood transfusion safety. The elevated seroprevalence for these three arboviruses is also indicative of their wide circulation in populations, correlating with an increased risk of infected but asymptomatic donors. Health centres and institutions must address this threat, especially in tropical regions where the biggest outbreaks occur.  相似文献   
98.
Context Opioids have been used as the reference treatment on chronic pain. However, they are related to serious adverse effects which affect the patient compliance to treatment, as well as, his quality of life. Particulate formulations have been investigated as an alternative to improve opioid efficacy and safety. Objective Summarise the available studies concerning micro and nanoencapsulated opioid formulations discussing their biopharmaceutical characteristics, such as composition, size, in vitro release, pharmacokinetic and antinociceptive profile. Methods Papers available in 1995–2015 at Medline, Science Direct and Web of Science databases were collected and assessed. Searches were performed using varied combinations of the keywords of this work. Results Opioid-loaded particles showed prolonged drug release with maintenance of serum therapeutic concentrations and extended analgesia when compared with the free drugs. The side effects incidences were reduced or maintained the same. Conclusion Particulate formulations can significantly increase both potency and safety profiles of opioids.  相似文献   
99.
This study is framed within the circular economy model through the valorisation of industrial by-products. This research shows the results of producing self-compacting mortars (SCMs) with electric arc furnace dust (EAFD) and other industrial by-products such as fly ash, conforming (FA) or not conforming (NcFA), from coal-fired power plants, or recovery filler (RF) from hot-mix asphalt plants. Three batches of SCMs, each with one industrial-by product (FA, NcFA, or RF), and three levels of EAFD ratio incorporation (0%, 10%, 20%), were tested. An extra batch with a greater amount of FA was manufactured. When the incorporation ratio of EAFD rose, the mechanical strength decreased, due to the presence of a calcium zinc hydroxide dihydrate phase; nevertheless, this decrease diminished over time. All SCM mixes, except the 40C 40FA 20 EAFD mix, were above 20 MPa at 28 days. All mixes named 70C and 40C reached 40 and 30 MPa, respectively, at 90 days. Mixes with EAFD showed less capillarity and no difference in water absorption by immersion with respect to mixes without EAFD after 91 days. The SCMs designed proved to be stable in terms of leaching of the heavy metals contained in EAFD, where all the hardened SCMs were classified as inert.  相似文献   
100.
目的:报道经玻璃体腔内注射高剂量曲安奈德(triamcinolone acetonide,TA)联合光动力学疗法(photodynamic therapy,PDT)治疗老年性黄斑变性( age related macular degeneration, AMD)的脉络膜新生血管(choroidal neovascularization,CNV)后发生的脉络膜毛细血管萎缩。方法:我们采用非随机回顾性干涉治疗病例。在阿利坎特学院眼科,连续观察51眼(实验组)玻璃体腔内的注射(19.4±2.1)mg/0.1mL TA联合PDT治疗AMD的全部中心凹下型CNV患者,经过2a的随访,检查黄斑部脉络膜毛细血管和视网膜色素上皮细胞(RPE)萎缩情况。同时,采用单独PDT治疗的连续30眼患者作为对照组,其年龄,性别和AMD的CNV类型及大小与实验组相匹配。结果:随访24mo后,在治疗区域21/47眼(45%,实验组)和7/30眼(23%,对照组)发展成黄斑部RPE和脉络膜毛细血管萎缩(P=0.04,卡方检验)。实验组平均最大萎缩区域的直径为(5044±1666)μm,而对照组为(4345±1550)μm。在实验组中,RPE萎缩患者的平均最佳矫正视力为(0.87±0.33),而非RPE萎缩患者的平均最佳矫正视力为(0.66±0.26) (P=0.11,秩和U检验)。结论:玻璃体腔内注射大剂量TA联合PDT治疗可能会增加RPE和脉络膜毛细血管萎缩的风险。  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