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   26959篇
  免费   1607篇
  国内免费   95篇
耳鼻咽喉   287篇
儿科学   697篇
妇产科学   599篇
基础医学   3758篇
口腔科学   1508篇
临床医学   1913篇
内科学   6562篇
皮肤病学   671篇
神经病学   2281篇
特种医学   584篇
外科学   3266篇
综合类   153篇
一般理论   14篇
预防医学   2124篇
眼科学   750篇
药学   1573篇
中国医学   108篇
肿瘤学   1813篇
  2023年   228篇
  2022年   466篇
  2021年   975篇
  2020年   585篇
  2019年   790篇
  2018年   943篇
  2017年   612篇
  2016年   675篇
  2015年   870篇
  2014年   1041篇
  2013年   1369篇
  2012年   2075篇
  2011年   2288篇
  2010年   1244篇
  2009年   1117篇
  2008年   1836篇
  2007年   1891篇
  2006年   1796篇
  2005年   1602篇
  2004年   1374篇
  2003年   1268篇
  2002年   1130篇
  2001年   221篇
  2000年   162篇
  1999年   216篇
  1998年   183篇
  1997年   155篇
  1996年   133篇
  1995年   123篇
  1994年   115篇
  1993年   99篇
  1992年   72篇
  1991年   78篇
  1990年   67篇
  1989年   59篇
  1988年   57篇
  1987年   49篇
  1986年   51篇
  1985年   44篇
  1984年   61篇
  1983年   56篇
  1982年   42篇
  1981年   61篇
  1980年   27篇
  1979年   32篇
  1978年   37篇
  1977年   31篇
  1976年   34篇
  1974年   23篇
  1973年   29篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
Journal of Neurology - To investigate the association of chronic obstructive pulmonary disease (COPD) and Preserved Ratio Impaired Spirometry (PRISm) with cognitive performance and presence of...  相似文献   
952.
European Archives of Psychiatry and Clinical Neuroscience - The hypothesis of the psychosis continuum enables to study the mechanisms of psychosis risk not only in clinical samples but in...  相似文献   
953.
954.
De novo donor‐specific antibodies (dDSA) relevance in simultaneous pancreas–kidney (SPK) transplantation has been scarcely investigated. We analyzed dDSA relationship with grafts outcomes in a long‐term follow‐up SPK‐transplanted cohort. In 150 patients that received SPK transplant between 2000 and 2013, post‐transplant anti‐human leukocyte antigen (HLA) antibodies were screened and identified using Luminex‐based assays in sera collected at 3, 6, and 12 months, then yearly. dDSA were detected in 22 (14.7%) patients at a median 3.1 years after transplant. Pretransplant anti‐HLA sensitization (OR = 4.64), full HLA‐DR mismatch (OR = 4.38), and previous acute cellular rejection (OR = 9.45) were significant risk factors for dDSA. dDSA were significantly associated with kidney (in association with acute rejection) and pancreas graft failure. In dDSA+ patients, those with at least one graft failure presented more frequently dDSA against class II or I + II (P = 0.011) and locusDQ (P = 0.043) and had a higher median dDSA number (P = 0.014) and strength (P = 0.030). Median time between dDSA emergence and pancreas and kidney graft failure was 5 and 12 months, respectively. Emergence of dDSA increased the risk of grafts failure in SPK‐transplanted patients. Full HLA‐DR mismatch was associated with dDSA emergence. dDSA characteristics might help identify patients at a higher risk of graft failure.  相似文献   
955.
956.

Purpose

The non-invasive expandable prosthesis for skeletally immature patients is used after limb salvage surgery following tumor resection. The aim of the study was to assess the effectiveness of this treatment.

Methods

Seven paediatric patients with femoral tumors had resection and limb salvage with an uncemented non-invasive growing prosthesis. Mean age at the time of surgery was 9.8 (range 8–12) years. There were six distal femur osteosarcomas and one proximal femur Ewing sarcoma. Six total knee prosthesis were implanted at the time of primary tumor resection and one bipolar hip prosthesis was a revision from a failed osteoarticular hip allograft. Functional outcomes and emotional acceptance were assessed using the MSTS score.

Results

The mean follow-up was 65.3 months (range 29–91) months. Two patients died of pulmonary metastasis and there was no local recurrence. The mean femoral resection was 18 cm (range 17–19) on the knee, and 24 cm on the hip. Mean total expansion was 36.4 mm (range 12.3–63.5). The mean MSTS score after rehabilitation was 26.3 (range 21–29). There was one lengthening device failure, one late infection and one patient who required iliofemoral bypass grafting surgery for a pelvic metastasis. No local recurrence occurred.

Conclusions

The non-invasive expandable prosthesis reduces the final limb-length discrepancy in growing patients with an acceptable function and appears to have an advantage as compared to invasive expandable prostheses which require multiple surgical procedures, but the complications rate is still high.
  相似文献   
957.
958.
Child and adolescent measures of the quality of life or subjective well-being are scarce in Latin American countries. Chile is no exception to this situation that represents a gap in the literature for South American countries research. Thus, the aim was to analyze the psychometric properties of the Personal Well-being Index for School Children (PWI-SC) of Cummins et al. Social Indicators Research, 64(2), 159–190, (2003) in a sample of Chilean school children. We use a sample of 1096 pupils between 10 and 12 years old (M?=?11.03; SD?=?0.89) and residents of three major Chilean cities. Results of Exploratory and Confirmatory Factor Analysis provided evidence for only one single factor solution. Moreover, an acceptable level of internal reliability was observed (α?=?0.77). The discussion of results considers other internationals applications of PWI-SC.  相似文献   
959.
Objective: The objective was to evaluate and compare the whole blood nitrite concentration in the three trimesters of pregnancy. Additionally, we investigate whether there is any relation between nitrite concentrations and Doppler ultrasound analysis of some maternal and fetal vessels.

Methods: Thirty-three healthy pregnant women were examined at the first (11–14 weeks), second (20–24 weeks) and third trimester (34–36 weeks) of pregnancy. In the three exams, we determined the maternal whole blood nitrite concentration and uterine arteries Doppler analysis to determine pulsatility index (PI), and resistance index (RI). In the second and third trimester we also performed fetal umbilical and middle cerebral arteries PI and RI. We compared the concentrations of nitrite in three trimesters and correlated with Doppler parameters.

Results: No difference was observed in the whole blood nitrite concentrations across trimesters: 151.70?±?77.90?nmol/ml, 142.10?±?73.50?nmol/ml and 147.10?±?87.30?nmol/ml; first, second and third trimesters, respectively. We found no difference in correlation between whole blood nitrite concentration and Doppler parameters from the evaluated vessels.

Conclusions: In healthy pregnant women, the nitrite concentrations did not change across gestational trimesters and there was also no strong correlation with Doppler impedance indices from maternal uterine arteries and fetal umbilical and middle cerebral arteries.  相似文献   
960.
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