全文获取类型
收费全文 | 429篇 |
免费 | 25篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 18篇 |
妇产科学 | 6篇 |
基础医学 | 26篇 |
口腔科学 | 14篇 |
临床医学 | 30篇 |
内科学 | 99篇 |
皮肤病学 | 2篇 |
神经病学 | 10篇 |
特种医学 | 94篇 |
外科学 | 33篇 |
综合类 | 21篇 |
预防医学 | 48篇 |
眼科学 | 5篇 |
药学 | 15篇 |
肿瘤学 | 36篇 |
出版年
2021年 | 8篇 |
2020年 | 5篇 |
2018年 | 9篇 |
2017年 | 6篇 |
2016年 | 6篇 |
2015年 | 12篇 |
2014年 | 8篇 |
2013年 | 21篇 |
2012年 | 12篇 |
2011年 | 5篇 |
2010年 | 19篇 |
2009年 | 10篇 |
2008年 | 20篇 |
2007年 | 7篇 |
2006年 | 7篇 |
2005年 | 11篇 |
2004年 | 9篇 |
2002年 | 6篇 |
2001年 | 5篇 |
2000年 | 7篇 |
1999年 | 6篇 |
1998年 | 19篇 |
1997年 | 20篇 |
1996年 | 18篇 |
1995年 | 12篇 |
1994年 | 14篇 |
1993年 | 9篇 |
1992年 | 5篇 |
1991年 | 5篇 |
1990年 | 7篇 |
1989年 | 13篇 |
1988年 | 6篇 |
1987年 | 7篇 |
1986年 | 11篇 |
1985年 | 6篇 |
1984年 | 10篇 |
1982年 | 5篇 |
1981年 | 5篇 |
1980年 | 10篇 |
1979年 | 3篇 |
1978年 | 8篇 |
1977年 | 9篇 |
1976年 | 6篇 |
1975年 | 5篇 |
1974年 | 3篇 |
1973年 | 3篇 |
1972年 | 6篇 |
1971年 | 3篇 |
1968年 | 4篇 |
1966年 | 3篇 |
排序方式: 共有458条查询结果,搜索用时 15 毫秒
21.
22.
23.
24.
Ting Ting Fu Heather C. Kaplan Trayce Fields Alonzo T. Folger Katelyn Gordon Brenda B. Poindexter 《Nutrients》2021,13(8)
Protein content is often inadequate in donor breast milk (DBM), resulting in poor growth. The use of protein-enriched target-pooled DBM (DBM+) has not been examined. We compared three cohorts of very low birth weight (VLBW) infants, born ≤ 1500 g: DBM cohort receiving > 1-week target-pooled DBM (20 kcal/oz), MBM cohort receiving ≤ 1-week DBM, and DBM+ cohort receiving > 1-week DBM+. Infants followed a standardized feeding regimen with additional fortification per clinical discretion. Growth velocities and z-scores were calculated for the first 4 weeks (n = 69 for DBM, 71 for MBM, 70 for DBM+) and at 36 weeks post-menstrual age (n = 58, 64, 59, respectively). In total, 60.8% MBM infants received fortification >24 kcal/oz in the first 30 days vs. 78.3% DBM and 77.1% DBM+. Adjusting for SGA, length velocity was greater with DBM+ than DBM in week 1. Average weight velocity and z-score change were improved with MBM compared to DBM and DBM+, but length z-score decreased similarly across all groups. Incidences of NEC and feeding intolerance were unchanged between eras. Thus, baseline protein enrichment appears safe in stable VLBW infants. Weight gain is greatest with MBM. Linear growth comparable to MBM is achievable with DBM+, though the overall length trajectory remains suboptimal. 相似文献
25.
Erythrocytes from individuals with pyruvate kinase (PK) deficiency have approximately half the total (oxidized and reduced) nicotinamide adenine dinucleotide (NAD) of normal erythrocytes. In order to elucidate the mechanism(s) for the decrease in total NAD, we examined NAD synthesis in intact erythrocytes. It is demonstrated that NAD synthesis is impaired in PK-deficient erythrocytes to a degree that is dependent on the PK activity and adenosine 5'-triphosphate (ATP) concentration of these cells. After incubation in the presence of fluoride, which simulates the characteristics of PK deficiency by inhibiting enolase, normal erythrocytes had impaired NAD synthesis and decreased ATP concentrations. Fluoride did not inhibit NAD synthesis in a hemolysate system that is not dependent on glycolysis for ATP generation. These data suggest that fluoride does not inhibit the enzymes of NAD synthesis and that impairment of NAD synthesis by fluoride is mediated by decreased ATP formation. Thus, it is concluded that impaired NAD synthesis in PK-deficient erythrocytes is caused by decreased ATP formation due to the PK deficiency. Since the rate of glycolysis is limited by the availability of NAD+, it is suggested that impaired NAD synthesis causes further ATP depletion and thereby may enhance hemolysis in PK-deficient erythrocytes. 相似文献
26.
SUSAN F. VERVOORDELDONK PAULINE A. MERLE HENK BEHRENDT ERIC J. STEENBERGEN HENK VAN DEN BERG ELISABETH R. VAN WERING ALBERT E. G. KR. VON DEM BORNE C. ELLEN VAN DER SCHOOT ELEONORE F. VAN LEEUWEN & INEKE C. M. SLAPER-CORTENBACH 《British journal of haematology》1997,96(2):395-402
Purging of autologous bone marrow (BM) grafts of children in second remission after a relapse of precursor B acute lymphoblastic leukaemia (ALL) in the BM has been carried out in our laboratory since 1987, initially by complement mediated cell lysis. This protocol was extended by performing an immunorosette depletion before lysis with complement. The aim of the present study was to assess by polymerase chain reaction the presence of residual leukaemic cells in the BM grafts before and after purging. The results were then correlated to clinical outcome. In 24/28 patients a PCR product was obtained by amplification of IgH and/or TcR junctional regions. BM before purging was available for analysis in 13 patients. We found that leukaemic cells could be detected in 8/13 (62%) of these grafts before purging . All these eight patients experienced a relapse, regardless of whether the purging procedure had been successful (defined as achievement of PCR-negativity) or not. In contrast, none of the five patients with PCR-negative grafts before purging relapsed ( P = 0.0008). One patient died due to transplant-related toxicity. Of the remaining 23 patients, nine patients received a PCR-positive BM graft after purging. All these nine patients experienced a relapse as compared to 6/14 whose BM was PCR-negative after purging ( P = 0.0072). Two of eight PCR-positive BM grafts could be purged to PCR-negativity. Thus, improvements both in treatment of leukaemia and in purging efficacy are still needed. 相似文献
27.
28.
Background: Nephrotic syndrome in children usually has an onset between 2–8 years of age and steroids form the mainstay of management. Therapy may affect growth in children with relapsing nephrotic syndrome. This study was carried out to correlate growth with the cumulative dose of steroids in children with steroid sensitive nephrotic syndrome (SSNS). 相似文献
29.
Templeton AW; Johnson JA; Anderson WH; Cook LT; Dwyer SJ d; Preston DF; Lee KR; Rosenthal SJ; Batnitzky S; Levine E 《Radiology》1984,151(2):527-528
The increasing use of digitally formatted imaging systems requires high-quality interactive gray-scale computer raster graphics systems for the management, display, and analog film recording of digital image and alphanumeric information. These systems are a combination of computer hardware and software and implement a set of graphics protocols. This paper describes a set of interactive graphics protocols that has been developed for clinical use. 相似文献
30.
The case of a newborn who had an umbilical catheter inserted in the intensive care unit is discussed. This catheter was meant to be inserted into the umbilical artery, but was instead inadvertently inserted into the umbilical vein. It crossed a patent foramen ovale into the left atrium. This fact was not known at the time of echocardiographic evaluation. At echocardiography, abnormal echoes within the left atrium were seen. Findings were typical for a catheter within the heart, and the umbilical catheter was subsequently withdrawn. There is a potential for mistaking the echocardiographic findings for a left atrial abnormality and echocardiographers should be alert to this possibility. 相似文献