全文获取类型
收费全文 | 25304篇 |
免费 | 2156篇 |
国内免费 | 80篇 |
专业分类
耳鼻咽喉 | 233篇 |
儿科学 | 510篇 |
妇产科学 | 352篇 |
基础医学 | 3493篇 |
口腔科学 | 763篇 |
临床医学 | 2731篇 |
内科学 | 5085篇 |
皮肤病学 | 362篇 |
神经病学 | 2255篇 |
特种医学 | 1272篇 |
外科学 | 3872篇 |
综合类 | 406篇 |
一般理论 | 22篇 |
预防医学 | 1967篇 |
眼科学 | 686篇 |
药学 | 1681篇 |
中国医学 | 19篇 |
肿瘤学 | 1831篇 |
出版年
2023年 | 164篇 |
2022年 | 288篇 |
2021年 | 595篇 |
2020年 | 361篇 |
2019年 | 505篇 |
2018年 | 577篇 |
2017年 | 462篇 |
2016年 | 510篇 |
2015年 | 632篇 |
2014年 | 804篇 |
2013年 | 1042篇 |
2012年 | 1668篇 |
2011年 | 1712篇 |
2010年 | 998篇 |
2009年 | 937篇 |
2008年 | 1432篇 |
2007年 | 1529篇 |
2006年 | 1360篇 |
2005年 | 1326篇 |
2004年 | 1195篇 |
2003年 | 1139篇 |
2002年 | 949篇 |
2001年 | 532篇 |
2000年 | 547篇 |
1999年 | 458篇 |
1998年 | 237篇 |
1997年 | 214篇 |
1996年 | 173篇 |
1995年 | 159篇 |
1994年 | 159篇 |
1993年 | 146篇 |
1992年 | 308篇 |
1991年 | 291篇 |
1990年 | 268篇 |
1989年 | 251篇 |
1988年 | 244篇 |
1987年 | 249篇 |
1986年 | 207篇 |
1985年 | 239篇 |
1984年 | 207篇 |
1983年 | 164篇 |
1982年 | 136篇 |
1981年 | 119篇 |
1979年 | 200篇 |
1978年 | 130篇 |
1977年 | 134篇 |
1976年 | 107篇 |
1973年 | 132篇 |
1972年 | 116篇 |
1971年 | 116篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
63.
The sonographic appearances in postpartum thyroiditis. 总被引:2,自引:0,他引:2
H Adams M C Jones S Othman J H Lazarus A B Parkes R Hall D I Phillips C J Richards 《Clinical radiology》1992,45(5):311-315
During the postpartum period about 50% of women with circulating thyroid autoantibodies develop a transient autoimmune thyroiditis. To determine the sonographic appearances in postpartum thyroiditis (PPT), serial ultrasound (US) scans of the thyroid were performed in 135 postpartum women who were divided into three clinical groups: Group 1, 37 antibody positive subjects who developed PPT; Group 2, 28 antibody positive subjects in whom thyroid function remained normal; Group 3, 70 antibody negative controls. Thyroid hypoechogenicity was observed in 14/31 patients (45%) who were scanned between 4 and 8 weeks postpartum and who subsequently developed PPT (Group 1) compared with 4/24 patients (17%) in Group 2 (P less than 0.05) and 1/65 patients (1.5%) in Group 3 (P less than 0.001). In antibody positive patients, the positive predictive value of an abnormal scan during this period was 78%. Between 15 and 25 weeks postpartum thyroid hypoechogenicity was present in 32/37 patients (86%) in Group 1 compared with 11/28 patients (39%) in Group 2 (P less than 0.001) and 2/70 patients (3%) in Group 3 (P less than 0.001). Sonographic abnormality persisted beyond 32 weeks postpartum in 36/41 antibody positive patients (87%) who had exhibited thyroid hypoechogenicity earlier during the study and who had late scans. The characteristic US appearance in PPT is thyroid hypoechogenicity. The role of sonography in the prediction, diagnosis and follow up of patients with PPT is discussed. 相似文献
64.
Summary Salvage radical retroperitoneal node dissection for large residual masses remaining after chemotherapy for testicular cancer was performed in 41 patients. In 10 instances it was possible to carry out a radical removal and attempt to preserve the sympathetic chain on one side. Ejaculation was preserved in 8 of these cases. Where removal of the mass was complete (33 cases) active cancer was present in 6, only one of whom developed tumor recurrence. Salvage node dissection is worthwhile, and in about 25% of cases can be performed with preservation of ejaculation. 相似文献
65.
David A. Sloan David M. Fleiszer Geoffrey K. Richards David Murray Rea A. Brown 《Journal of surgical oncology》1993,52(2):77-82
Sixty Sprague-Dawley rats were pair-fed one of three nutritionally identical diets. One diet contained “low-fiber” (3.8% crude fiber); the others contained “high fiber” (28.7% crude fiber) composed of either cellulose or lignin. Although both “high fiber” diets had similar stool bulking effects, only the cellulose diet was associated with a reduction in 1,2-dimethylhydrazine (DMH)-induced colon neoplasms. The cellulose diet was also associated with distinct changes in the gut bacterial profile and with a lowered serum cholesterol. © 1993 Wiley-Liss, Inc. 相似文献
66.
67.
IgA nephropathy and polycystic kidney disease 总被引:1,自引:0,他引:1
J M Panisello A Martinez-Vea C Garcia M Carrera J A Oliver C Richart 《American journal of nephrology》1988,8(6):477-478
We report a patient with polycystic kidney disease, advanced renal failure, and nephrotic-range proteinuria. Kidney biopsy revealed IgA nephropathy with lesions of focal and segmental glomerular sclerosis. This association had not been previously described and is probably coincidental. This case supports the assumption that the nephrotic-range proteinuria observed in some polycystic patients could be the consequence of another superimposed glomerular disease. This glomerulopathy can worsen the course of azotemia in these patients. 相似文献
68.
M. Sivakumaran Stephen J. Richards Kaye M. Hunt rew J. Steed A. Geraldine Bynoe Mary M. Morgan Roger Pyrah Bryon E. Roberts Colin Stephen Scott 《British journal of haematology》1991,78(3):368-377
Phenotypic characteristics, and correlations between the expression of membrane NK-associated (NKa) determinants (CD11b, CD16, CD56 and CD57) and T cell receptor (TCR) genotypic patterns, were examined in 25 patients with persistent (greater than 6 months) expansions of CD3+WT31+NKa+ (CD8+ and CD8dim+) lymphocytes. These studies showed that distinct NKa phenotypic profiles were restricted to cases with rearranged TCR configurations and that clonal CD3+NKa+ components could be predicted in most cases by assessing relationships between membrane CD16 and CD56 expression. For all normal NKa subpopulations, there was a high correlation (P less than 0.0001; n = 31) between the expression of these two membrane determinants. Markedly increased CD16 expression by CD3+NKa+ cells, in relation to CD56 (i.e. a high CD16:CD56 ratio), was found exclusively in cases with rearranged TCR (13/16 cases); 2/3 of the remaining cases showing significantly reduced CD16:CD56 ratios and high (greater than 2.0) CD3+CD56+ absolute numbers. In contrast, 7/9 of the germline TCR cases had a normal CD16:CD56 ratio and 2/9 a decreased ratio with low (less than 1.0) CD3+CD56+ absolute numbers. A high ratio of CD16:CD56 expression by CD3+NKa+ lymphocytes was therefore informative for 82% of TCR rearrangements in this series; and analysis of CD16 and CD56 expression was predictive for germline and rearranged TCR configurations in 24/25 persistent CD3+NKa+ expansions. 相似文献
69.
The retinal pigment epithelium (RPE) plays several important roles in the continual support and renewal of photoreceptor outer segments. In the present study, we have demonstrated that RPE cells contain a low molecular weight protein with a high capacity for zinc binding that is dependent on available sulfhydryl groups. This protein is inducible by a 24 hour incubation of cultured RPE in medium supplemented with zinc, cadmium, or dexamethasone. The induction of this protein is correlated with an increased capacity for zinc-65 uptake into cultured RPE. Analysis with a cDNA probe specific for the human metallothionein II gene corroborated the existence and induction of metallothionein gene products in RPE cells. Based on these properties, we have identified this protein as metallothionein. The induction of metallothionein likely has a critical influence on the zinc economy of the RPE. 相似文献
70.
Intensive versus standard blood glucose awareness training (BGAT) with insulin-dependent diabetes: mechanisms and ancillary effects 总被引:1,自引:0,他引:1
D J Cox L Gonder-Frederick D Julian P Cryer J H Lee F E Richards W Clarke 《Psychosomatic medicine》1991,53(4):453-462
Insulin-dependent diabetes mellitus (IDDM) patients make critical daily self-care decisions on the basis of what they estimate their blood glucose (BG) levels to be. This study: a) replicated efficacy of Standard Blood Glucose Awareness Training (BGAT), b) evaluated the relative efficacy of an Intensive Blood Glucose Awareness Training (BGAT) to enhance patient accuracy of BG estimation, and c) evaluated the mechanisms and ancillary effects of BGAT. Thirty-nine subjects were randomly assigned to one of three groups. Compared with Control, both Standard and Intensive BGAT improved accuracy (p less than 0.001). Intensive BGAT post-treatment accuracy relative to Standard BGAT did not reach statistical significance (p = 0.177). Greater improvement in accuracy was associated with poorer pretreatment accuracy. Only Intensive BGAT improved metabolic control (glycosylated hemoglobin), and this improvement was associated with poorer pretreatment control. The effects of BGAT were highly specific, affecting only accuracy and metabolic control, and not affecting fear of hypoglycemia, diabetes knowledge, of frequency of blood glucose monitoring. 相似文献