全文获取类型
收费全文 | 4320篇 |
免费 | 241篇 |
国内免费 | 36篇 |
专业分类
耳鼻咽喉 | 68篇 |
儿科学 | 96篇 |
妇产科学 | 52篇 |
基础医学 | 583篇 |
口腔科学 | 111篇 |
临床医学 | 485篇 |
内科学 | 823篇 |
皮肤病学 | 33篇 |
神经病学 | 350篇 |
特种医学 | 180篇 |
外科学 | 802篇 |
综合类 | 71篇 |
一般理论 | 2篇 |
预防医学 | 275篇 |
眼科学 | 81篇 |
药学 | 333篇 |
中国医学 | 11篇 |
肿瘤学 | 241篇 |
出版年
2022年 | 37篇 |
2021年 | 62篇 |
2020年 | 27篇 |
2019年 | 44篇 |
2018年 | 65篇 |
2017年 | 44篇 |
2016年 | 57篇 |
2015年 | 77篇 |
2014年 | 105篇 |
2013年 | 164篇 |
2012年 | 201篇 |
2011年 | 202篇 |
2010年 | 106篇 |
2009年 | 123篇 |
2008年 | 176篇 |
2007年 | 195篇 |
2006年 | 184篇 |
2005年 | 225篇 |
2004年 | 189篇 |
2003年 | 167篇 |
2002年 | 166篇 |
2001年 | 163篇 |
2000年 | 144篇 |
1999年 | 138篇 |
1998年 | 50篇 |
1997年 | 45篇 |
1996年 | 36篇 |
1995年 | 37篇 |
1992年 | 101篇 |
1991年 | 79篇 |
1990年 | 82篇 |
1989年 | 78篇 |
1988年 | 74篇 |
1987年 | 75篇 |
1986年 | 50篇 |
1985年 | 63篇 |
1984年 | 50篇 |
1983年 | 31篇 |
1982年 | 34篇 |
1981年 | 36篇 |
1980年 | 32篇 |
1979年 | 38篇 |
1978年 | 36篇 |
1976年 | 29篇 |
1975年 | 28篇 |
1974年 | 32篇 |
1973年 | 33篇 |
1972年 | 31篇 |
1971年 | 36篇 |
1970年 | 28篇 |
排序方式: 共有4597条查询结果,搜索用时 0 毫秒
11.
12.
The v-erbA oncogene, a mutated version of the thyroid hormone receptor alpha (c-erbA/TR-alpha), cooperates with tyrosine kinase oncogenes in erythroblast transformation. Here we show that the ligand-activated, endogenous retinoic acid receptor (RAR-alpha), in cooperation with c-erbA/TR-alpha, efficiently reverses the transforming effect of kinase oncogenes, overcoming oncogene-induced self-renewal by triggering terminal differentiation of the transformed cells into healthy erythrocytes. This differentiation induction was accompanied by up-regulation of erythrocyte gene expression. Similarly, RAR-alpha and over-expressed exogenous c-erbA/TR-alpha efficiently abolished the differentiation arrest caused by v-erbA, while the low levels of endogenous TR-alpha had no effect. In contrast, transformation by v-erbA plus a kinase oncogene was not affected at all by ligand-activated endogenous or over-expressed exogenous TR-alpha and RAR-alpha. These results suggest that oncogene cooperation is required to protect leukemic erythroblasts from differentiation induction via endogenous, nuclear hormone receptors. Endogenous c-erbA/TR-alpha and RAR-alpha apparently cooperated in abolishing erythroblast self-renewal and inducing differentiation, since the respective ligands acted in a synergistic fashion, and overexpressed, non-ligand-bound c-erbA/TR-alpha suppressed endogenous RAR-alpha function in differentiation induction. Genetic evidence is presented that this functional cooperation requires the receptor dimerization domain, suggesting that TR-alpha/RAR-alpha heterodimers play a role in regulation of erythroid differentiation. 相似文献
13.
H Schroeder C R Pinkerton R L Powles S T Meller D Tait S Milan T J McElwain 《Bone marrow transplantation》1991,7(1):11-15
High dose melphalan (HDM 110-140 mg/m2) and total body irradiation (TBI, 10.5 Gy, single fraction) followed by infusion of autologous bone marrow (ABMT) was evaluated for toxicity and efficacy in 24 children with acute lymphoblastic leukaemia (ALL) in second (CR2) or third remission (CR3). Marrow was purged with Campath 1 in six children (four were children in CR3). All children had engraftment with a median of 30 days (range 18-70 days) to neutrophil count greater than 0.5 x 10(9)/l. Four children (16%) died from toxicity 1-4 months after autograft, two from pneumonitis, one from an intracerebral haemorrhage and one from sepsis. Apart from fever and mucositis the procedure was well tolerated. Nine of 17 children treated in CR2 remain in complete remission 6-72 months after ABMT (median 25 months). Seven of these have a follow-up of greater than 12 months. Three of the seven children treated in CR3 are alive 17, 22 and 29 months post ABMT. Seven children relapsed within 10 months (median 4 months) of the autograft. Only one relapse has occurred beyond 10 months. HDM and TBI followed by ABMT is a relatively well tolerated regimen and may contribute to survival in children with relapsed ALL. 相似文献
14.
15.
H H Euler J O Schroeder 《The New England journal of medicine》1992,327(14):1028; author reply 1029-1028; author reply 1030
16.
P R Turkki L Ingerman L A Schroeder R S Chung M Chen M A Russo-Mcgraw J Dearlove 《Journal of the American College of Nutrition》1992,11(3):272-282
To assess the need for postoperative vitamin supplements, intakes and nutritional status of thiamin (B1) and vitamin B6 were studied in 18 female gastroplasty patients who received a placebo or different levels of supplemental vitamins. Postoperative erythrocyte transketolase basal (BA) and thiamin pyrophosphate-stimulated (SA) activities and activity coefficients (AC) correlated significantly with B1 intake. Despite a decrease in apotransketolase, low thiamin intakes were associated with increased AC values during the first 3 months. With return to low B1 intakes following repletion during month 4, the AC values remained normal with low total activities. Both alanine (EALT) and aspartate (EAST) aminotransferase apoenzyme levels declined and AC values increased significantly during the first 3 months. Although the EALT-indices were more sensitive to changes in B6 intake than the EAST-indices, the EASTBA and SA correlated most consistently with the intake. Postoperative dietary intakes of both vitamins were inadequate for maintenance of normal activities of these erythrocyte enzymes. Although B1 intake of greater than or equal to 1.0 mg/day was adequate for maintenance of normal thiamin status in most subjects of this study, supplementation with greater than or equal to 1.5 mg/day is prudent even though it may not prevent the early postoperative loss of apotransketolase. Vitamin B6 intake at the current recommended dietary allowance (1.6 mg) was not adequate to maintain coenzyme saturation of the erythrocyte aminotransferases. Marginal intake of other nutrients may have affected the utilization of both thiamin and vitamin B6. 相似文献
17.
H H Euler J O Schroeder R A Zeuner E Teske 《The International journal of artificial organs》1991,14(10):639-646
A group of clinics cooperating as the Lupus Plasmapheresis Study Group (LPSG) is starting an international multicenter study of the treatment of severe systemic lupus erythematosus. The primary goal of this randomized and prospective trial is to establish whether treatment with plasmapheresis and subsequent pulse cyclophosphamide improves the outcome compared to treatment with pulse cyclophosphamide alone. The underlying rationale assumes that plasmapheresis: a) eliminates pathogenic autoantibodies and immune complexes and b) induces a compensatory activation of pathogenic lymphocyte clones through a feed-back between circulating antibodies and their respective antibody-producing clones. Synchronization of plasmapheresis with subsequent pulse cyclophosphamide should enhance the deletion of pathogenic clones during the period of greatest vulnerability. This overview reviews the first results of treatment approaches based on this concept and summarizes the design of the LPSG trial. 相似文献
18.
19.
E. Eric Muirhead David H. P. Streeten Bennie Brooks Edward T. Schroeder Lawrence W. Byers 《Blood pressure》1992,1(3):138-148
A new syndrome is described in a patient with advanced renal insufficiency. This consists of severe and persistent hypotension causing weakness but associated with a clear mental status. Also present is evidence for decreased vascular reactivity. The hypotension was not orthostatic. The hypotension was associated with a circulating vasodepressor substance having the characteristics of medullipin I. The medullipin appears to have been derived from the remaining right kidney. Hypotension existed despite the presence of major prohypertensive mechanisms, including an endstage kidney, hyperreninemia and hyperaldosteronemia. It is likely that hypotension due to hypermedullipinemia is an entity occurring in the human being. 相似文献
20.
W J Chwals M E Fernandez B J Charles L A Schroeder C S Turner 《Journal of pediatric surgery》1992,27(3):317-20; discussion 320-1
Protein catabolism resulting from acute metabolic stress causes significant postoperative decreases in visceral proteins, including albumin (Alb) and prealbumin (PA). Although clinical trials have suggested an advantage of PA over Alb in monitoring the visceral protein response to nutritional supplementation following surgery, the capability of the neonate to generate such a response has yet to be evaluated. Therefore, this study was undertaken to determine if PA is superior to Alb in assessing postoperative repletion of the visceral protein pool in neonates. Serum Alb and PA levels were measured and energy balance (EB) and protein intake (PI) were recorded in 10 neonates less than 48 hours after major surgery and again following 4 consecutive days of positive EB. Resting energy expenditure (REE) was measured using indirect calorimetric methodology. Mean PI (g/kg/d) was lower (0.78 +/- 0.78) and mean EB (kcal/kg/d) was negative (-2.92 +/- 10.05) less than 48 hours postoperatively compared with mean PI (2.52 +/- 0.57; P = .0006) after 4 consecutive days of positive EB (34.84 +/- 16.5; P = .0004). Mean percent change (mean% delta) from negative EB to positive EB was significantly greater for PA (100%; P = .0002) as compared with Alb (18.5%). These data appear to support the conclusion that serial serum PA levels are superior to Alb to monitor the visceral protein response to nutritional supplementation in neonates following surgery. 相似文献