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   22449篇
  免费   753篇
  国内免费   255篇
耳鼻咽喉   178篇
儿科学   644篇
妇产科学   4370篇
基础医学   1277篇
口腔科学   115篇
临床医学   2521篇
内科学   2442篇
皮肤病学   262篇
神经病学   1389篇
特种医学   325篇
外科学   2535篇
综合类   2374篇
预防医学   2738篇
眼科学   32篇
药学   1576篇
  8篇
中国医学   242篇
肿瘤学   429篇
  2023年   290篇
  2022年   686篇
  2021年   1030篇
  2020年   895篇
  2019年   834篇
  2018年   849篇
  2017年   787篇
  2016年   837篇
  2015年   771篇
  2014年   1740篇
  2013年   1797篇
  2012年   1208篇
  2011年   1428篇
  2010年   1135篇
  2009年   1277篇
  2008年   1160篇
  2007年   1096篇
  2006年   1017篇
  2005年   778篇
  2004年   660篇
  2003年   483篇
  2002年   374篇
  2001年   307篇
  2000年   343篇
  1999年   231篇
  1998年   198篇
  1997年   190篇
  1996年   127篇
  1995年   121篇
  1994年   104篇
  1993年   74篇
  1992年   63篇
  1991年   66篇
  1990年   47篇
  1989年   45篇
  1988年   45篇
  1987年   37篇
  1986年   24篇
  1985年   59篇
  1984年   43篇
  1983年   24篇
  1982年   32篇
  1981年   23篇
  1980年   19篇
  1979年   16篇
  1978年   21篇
  1977年   13篇
  1976年   8篇
  1975年   13篇
  1973年   8篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
《Vaccine》2016,34(39):4732-4737
Shiga toxin producing Escherichia coli (STEC) are bacterial pathogens involved in food-borne diseases. Shiga toxin (Stx) is the main virulence factor of STEC and is responsible for systemic complications including Hemolytic Uremic Syndrome (HUS). It has been previously demonstrated that Shiga toxin type 2 (Stx2) induces pregnancy loss in rats in early stage of pregnancy. The main purpose of this study was to determine if an active immunization prevents Stx2 mediated pregnancy loss and confers passive protective immunity to the offspring. For that purpose Sprague Dawley female rats were immunized with the chimera based on the enzyme lumazine synthase from Brucella spp. (BLS) and the B subunit of Shiga toxin 2 (Stx2B) named BLS-Stx2B. After immunization females were mated with males. At day 8 of gestation, dams were challenged intraperitoneally with a sublethal and abortifacient dose of Stx2. The immunization induced high anti-Stx2B-specific antibody titers in sera and most important, prevented pregnancy loss. Pups born and breastfeed by immunized dams had high anti-Stx2B-specific antibody titers in sera. Cross-fostering experiments indicated that passive protective immunity against Stx2 was transmitted through lactation. These results indicate that immunization of adult female rats with BLS-Stx2B prevents Stx2-induced pregnancy loss and confers anti Stx2 protective immunity to the offspring.  相似文献   
22.
目的 探析正念减压疗法对妊娠呕吐妇女负性情绪和生活质量的影响。 方法 将2017年5月-2018年5月在我院治疗的90例妊娠呕吐妇女纳入本研究,采用数字表法随机分成研究组和对照组,每组各45例。对照组接受宣教,研究组在对照组上实施正念减压疗法。分别于入组时、干预4周和干预8周采用焦虑自评量表(self-rating anxiety scale,SAS)、抑郁自评量表(self-rating depression scale,SDS)、生活质量综合评定问卷(generic quality of life inventory-74,GQOLI-74)进行评估,比较2组妊娠呕吐妇女负性情绪和生活质量。 结果 2组SAS、SDS评分及生活质量综合评定问卷总分在组间效应、时间效应及交互效应上差异具统计学意义。 结论 妊娠呕吐妇女进行正念减压疗法,能够显著减轻妊娠呕吐妇女负性情绪和提高生活质量,值得在临床上广泛应用。  相似文献   
23.
李焱  翟凤霞 《陕西中医》2020,(5):660-662
妊娠期间,咳嗽不已,称"妊娠咳嗽",亦称"子嗽",孕妇咳嗽日久未见好转,咳嗽胸痛甚则咳而呕吐,或咳嗽剧烈或久咳不愈,可损伤胎气,导致堕胎、小产。笔者运用六经辨证治疗外感型中表寒里热证子嗽,认为此类患者病在太阳阳明,属于寒热错杂之表寒里热,采用《伤寒论》中方证麻杏甘石汤合止嗽散,使热从外泄,宣发卫气,散寒不助热、解表不伤正,故辨证论治取得了显著的疗效。同时子嗽治疗还需注意健脾固肾安胎,应将顾护胎元贯穿治疗妊娠咳嗽的始终。  相似文献   
24.
张莹莹  王才智 《安徽医药》2016,37(5):550-553
目的 研究胎膜早破孕妇生殖道感染情况及对妊娠结局的影响。方法 选择2014年5月至2015年1月住院分娩的胎膜早破孕妇70例为早破组,同期无胎膜早破70例为对照组,检测两组生殖道病原微生物感染情况,并比较两组的妊娠结局。结果 早破组生殖道感染阳性率高于对照组,且剖宫产率,母体发生产后出血,绒毛膜羊膜炎,胎儿窘迫及新生儿窒息发生率均高于对照组,差异均有统计学意义(P<0.05)。结论 生殖道感染是胎膜早破最常见的诱因,积极筛查及治疗孕妇生殖道感染可以减少相关产科并发症的发生。  相似文献   
25.
ObjectiveBorderline ovarian tumours (BOTs) are characterized by the presence of cellular proliferation and nuclear atypia without stromal invasion. Compared to malignant ovarian tumours, BOTs have better prognoses. The most important treatment of BOT is surgery. Considering the good prognosis of BOT, fertility-sparing surgery (FSS) can be considered for young women who desire to preserve fertility. Our study evaluated the pregnancy rate in patients with childbearing desire, the efficacy and risk of recurrence of women affected by BOTs who have undergone FSS.Materials and methodsPatients characteristics have been restrospectively retrieved for diagnosis made from June 2000 to December 2017 from San Raffaele Hospital and Policlinico Cagliari. Patients underwent FSS for BOT were interviewed about child wishing and pregnancy outcomes.Results85 patients were recruited for the study. Median age at diagnosis was 33 years. Unilateral salpingo-oophorectomy was performed in 33 patients (38%), unilateral cystectomy in 40 (47%) and 12 underwent both procedures (14%). 40 women (50%) tried to conceive after surgery. The pregnancy rate was 73% and live birth rate was 67%. Childbearing desire and age at diagnosis were significantly associated with the pregnancy rate.ConclusionsConservative surgical treatment seems to be a reasonable therapeutic option for women with BOTs who wish to preserve fertility. Our results suggest that the obstetric outcomes after FSS are promising. Maternal desire and the age of diagnosis are the most important factors affecting PR after surgery. Fertility counselling should be an integral part of the clinical management of women with BOT.  相似文献   
26.
目的探讨胎盘植入性疾病的危险因素及妊娠结局。 方法回顾性分析2009年1月至2017年12月广州医科大学附属第三医院/广州重症孕产妇救治中心围产资料数据库中信息完整的单胎妊娠孕妇48 650例临床资料,将这些孕妇分为胎盘植入性疾病组和非胎盘植入性疾病组,分析胎盘植入性疾病的危险因素及其妊娠结局。 结果单因素分析显示,年龄≥35岁、高中教育水平及以下、孕次≥3次、经产妇、人工流产史、剖宫产史、体外受精-胚胎移植受孕、合并前置胎盘是胎盘植入性疾病的相关危险因素(P<0.05)。多因素logistic回归分析显示,胎盘植入性疾病的独立危险因素为剖宫产史(OR=2.254,95%CI:1.917~2.650)、体外受精-胚胎移植受孕(OR=1.591,95%CI:1.212~2.089)、合并前置胎盘(OR=28.282,95%CI:24.338~32.866);与非胎盘植入性疾病产妇相比,患有胎盘植入性疾病产妇早产、剖宫产、产后出血、弥散性血管内凝血、产褥期感染、子宫切除、低出生体重儿、新生儿Apgar评分相对较低(1 min)、产妇入住重症监护病房的发生率明显升高(P<0.05)。 结论剖宫产史、辅助生殖受孕、合并前置胎盘是引起胎盘植入性疾病的独立危险因素,胎盘植入性疾病的妊娠结局不良。  相似文献   
27.
目的探讨3D打印模型在儿童先天性脊柱侧凸治疗中的应用疗效。方法回顾性分析2015年12月至2016年12月于首都医科大学附属北京儿童医院接受手术治疗的83例先天性脊柱侧凸患儿临床及影像学资料,根据是否使用3D打印模型分为试验组(n=44)和对照组(n=39),比较两组手术时间、术中透视次数、置钉准确性、矫形效果及并发症情况。结果本研究共纳入83例先天性脊柱侧凸患儿,其中男童47例,女童36例,平均手术年龄5.98 (1.5~13)岁。行半椎体切除术40例,Ponte截骨术31例,经椎弓根截骨术8例,全脊椎切除术4例。随访时间24~35个月。试验组患儿手术时间短于对照组[(180.92±16.74) min (201.51±27.60) min],差异有统计学意义(t=2.798,P<0.05),试验组术中出血量[(340.23±89.52) mL vs.(392.64±100.41) mL]及术中透视次数(4.36±0.89 6.05±1.28)明显少于对照组,差异有统计学意义(P<0.05);试验组置钉准确率高于对照组(93.55%vs 79.91%)(X^2=218.00,P<0.05),平均置钉时间明显短于对照组[(4.24±1.05) min vs.(8.35±2.29) min],差异有统计学意义(t=10.71,P<0.05)。两组患儿矫形率无明显差异(t=-1.135,P=0.272)。试验组与对照组患儿术后胸膜损伤、硬膜损伤发生率无明显差异(P>0.05)。结论 3D打印模型能清晰、直观显示先天性脊柱侧凸患儿的脊柱结构及形态,为制定手术计划及手术置钉提供帮助,从而提高置钉准确率,减少术中透视次数,缩短手术时间,减少术中出血量。  相似文献   
28.

BACKGROUND CONTEXT

Health-related quality of life (HRQOL) parameters have been shown to be reliable and valid in patients with adult spinal deformity (ASD). Minimum clinically important difference (MCID) has become increasingly important to clinicians in evaluating patients with a threshold of improvement that is clinically relevant.

PURPOSE

To calculate MCID and minimum detectable change (MDC) values of total scores of the Core Outcome Measures Index (COMI), Oswestry Disability Index (ODI), Physical Component Summary (PCS), Mental Component Summary (MCS) of the Short Form 36 (SF-36), and Scoliosis Research Society 22R (SRS-22R) in surgically and nonsurgically treated ASD patients who have completed an anchor question at pretreatment and 1-year follow-up.

STUDY DESIGN/SETTING

Prospective cohort.

PATIENT SAMPLE

Surgical and nonsurgical patients from a multicenter ASD database.

OUTCOME MEASURES

Self-reported HRQOL measures (COMI, ODI, SF-36, SRS-22R, and anchor question).

METHODS

A total of 185 surgical and 86 nonsurgical patients from a multicenter ASD database who completed pretreatment and 1-year follow-up HRQOL scales and the anchor question at the first year follow-up were included. The anchor question was used to determine MCID for each HRQOL measure. MCIDs were calculated by an anchor-based method using latent class analysis (LCA) and MDCs by a distribution-based method.

RESULTS

All differences between means of baseline and first year postoperative total score measures for all scales demonstrated statistically significant improvements in the overall population as well as the surgically treated patients but not in the nonsurgical group. The calculated MDC and MCID values of HRQOL parameters in the entire study population were 1.34 and 2.62 for COMI, 10.65 and 14.31 for ODI, 6.09 and 7.33 for SF-36 PCS, 6.14 and 4.37 for SF-36 MCS, and 0.42 and 0.71 for SRS-22R. The calculated MCID values for surgical and non-surgical treatment groups were 2.76 versus 1.20 for COMI, 14.96 versus 2.45 for ODI, 7.83 versus 2.15 for SF-36 PCS, 5.14 versus 2.03 for SF-36 MCS, and 0.94 versus 0.11 for SRS-22R; the MDC values for surgical and nonsurgical treatment groups were 1.22 versus 1.51 for COMI, 10.27 versus 9.45 for ODI, 5.16 versus 6.77 for SF-36 PCS, 6.05 versus 5.67 for SF-36 MCS, and 0.38 versus 0.43 for SRS-22R.

CONCLUSIONS

This study has demonstrated that MCID calculations for the HRQOL scales in ASD using LCA yield values comparable to other studies that had used different methodologies. The most important finding was the significantly different MCIDs for COMI, ODI, SF-36 PCS and SRS-22 in the surgically and nonsurgically treated cohorts. This finding suggests that a universal MCID value, inherent to a specific HRQOL for an entire cohort of ASD may not exist. Use of different MCIDs for surgical and nonsurgical patients may be warranted.  相似文献   
29.

Background

Herbal medicine has been widely utilized by pregnant women despite the limited available evidence regarding the safety and efficacy of that practice. The current available studies, from different countries, estimated that the use of herbal medicine during pregnancy range from 7% up to 96%. The aim of this study is to determine the prevalence, attitude, source of information, and reasoning behind the use of herbal medicine among pregnant women in Saudia Arabia.

Methods

A cross-sectional study conducted using a convenience sample including pregnant women who visited the obstetric clinics at King Abdulaziz Medical City in Riyadh, Saudi Arabia. A survey was administered in order to evaluate the prevalence and perception toward herbal medicine use among pregnant women in Saudi Arabia.

Results

A total of 297 pregnant women completed the survey. The results showed that 56% of the respondents have used some type of herbal medicine during their pregnancy. Olive oil was utilized in 26% of the respondents followed by cumin 20% and garlic 15%. In addition, 37% of the respondents used herbal medicine by their own initiative, while 33% and 12% used herbal medicine based on recommendations from their families and friends, respectively. Furthermore, 19% of the respondents reported a positive attitude toward herbal medicine use during pregnancy. In addition, the percentage of women with positive attitude was marginally higher among respondents with lower educational level.

Conclusion

The prevalence of using herbal medicine is considerably high among pregnant women in Saudi Arabia. Unfortunately, the majority of the users relied on informal sources to use herbal medicine during pregnancy.  相似文献   
30.
ObjectiveThe aim of this study was to discuss the clinical characteristics and the prognosis of surgically diagnosed endometriosis complicated by endometrial polyps and investigate the association between pregnancy outcomes during subsequent pregnancies.Materials and methodsFrom January 2013 to December 2016, 1263 infertile patients were enrolled in the study. We identified 451 patients with endometriosis, and divided them into a polyp group (n = 204) and a non-polyp group (n = 247) based on whether or not they were associated with endometrial polyps. Postoperative clinical pregnant women (n = 82) among the polyp group were then classified into a study group and a control group composed of those undergoing a singleton pregnancy (n = 164) who delivered during the same time period. Clinical statuses and complications during pregnancy and delivery were collected from hospitals and by telephone interviews and surveys through the mail.ResultsThe prevalence rate of endometriosis infertile group was obviously higher than the non-endometriosis infertile group ([45.23%; 204/451] versus [17.12%; 139/812]). Women suffering from stage 1 to 4 endometriosis had a 42.44% (73/172), 40.69% (59/145), 55.89% (38/68) and 51.52% (34/66) occurrence rate of endometrial polyps, respectively. The frequency of endometrial polyps for stage 3 and 4 patients was obviously higher than that of stage 1 and 2 patients ([53.73%; 72/134] versus [41.64%; 132/317]). Moreover, the occurrence rate of deep infiltrating endometriosis (DIE) was 57.81% (37/64), which was obviously higher than that of ovarian endometriosis (42.42%; 98/231) and peritoneal endometriosis (44.23%; 69/156). Of the 204 women diagnosed with posterior endometrial polyps, 89 became pregnant, 7 pregnancies ended in a spontaneous abortion, and 82 successfully delivered a baby. The clinical pregnancy rate of patients in stages 1 and 2 was wholly higher than that of patients in stages 3 and 4 ([48.70%; 56/115] versus [37.71%; 26/82]). The postsurgical pregnancy status of patients suffering from peritoneal endometriosis was slightly better than those with ovarian or DIE, but differences were not statistically significant (P = 0.626). We also found that the pregnancy rate was statistically elevated in patients whose EFI scores range from 7 to 10. When compared to the control group, women with endometriosis and endometrial polyps had a higher risk of their pregnancy being complicated by placenta previa (13.41%) and cesarean delivery (59.76%).ConclusionPatients with endometriosis have a higher frequency of endometrial polyps. We found that a combined hysteroscopy and laparoscopy surgical procedure is an effective way to increase pregnancy rates. Different endometriosis stages and types in patients were associated with clinical pregnancy and spontaneous abortion rates. Women affected by both endometriosis and endometrial polyps have an independently elevated risk of placenta previa and cesarean delivery during pregnancy.  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