全文获取类型
收费全文 | 1473358篇 |
免费 | 104073篇 |
国内免费 | 2379篇 |
专业分类
耳鼻咽喉 | 20768篇 |
儿科学 | 48378篇 |
妇产科学 | 41840篇 |
基础医学 | 215414篇 |
口腔科学 | 40122篇 |
临床医学 | 124009篇 |
内科学 | 294703篇 |
皮肤病学 | 31832篇 |
神经病学 | 117144篇 |
特种医学 | 56031篇 |
外国民族医学 | 457篇 |
外科学 | 222176篇 |
综合类 | 27376篇 |
现状与发展 | 1篇 |
一般理论 | 359篇 |
预防医学 | 110833篇 |
眼科学 | 33081篇 |
药学 | 111704篇 |
1篇 | |
中国医学 | 3095篇 |
肿瘤学 | 80486篇 |
出版年
2019年 | 11509篇 |
2018年 | 18417篇 |
2017年 | 13283篇 |
2016年 | 14410篇 |
2015年 | 16429篇 |
2014年 | 21038篇 |
2013年 | 32471篇 |
2012年 | 47706篇 |
2011年 | 50060篇 |
2010年 | 28224篇 |
2009年 | 25229篇 |
2008年 | 47032篇 |
2007年 | 50837篇 |
2006年 | 50308篇 |
2005年 | 49470篇 |
2004年 | 47197篇 |
2003年 | 45262篇 |
2002年 | 44226篇 |
2001年 | 62628篇 |
2000年 | 64181篇 |
1999年 | 54762篇 |
1998年 | 15012篇 |
1997年 | 13464篇 |
1996年 | 13666篇 |
1995年 | 12895篇 |
1994年 | 12241篇 |
1992年 | 43375篇 |
1991年 | 42507篇 |
1990年 | 41949篇 |
1989年 | 40563篇 |
1988年 | 37851篇 |
1987年 | 36937篇 |
1986年 | 35215篇 |
1985年 | 33535篇 |
1984年 | 24945篇 |
1983年 | 21697篇 |
1982年 | 12923篇 |
1981年 | 11364篇 |
1979年 | 23551篇 |
1978年 | 16511篇 |
1977年 | 14300篇 |
1976年 | 13468篇 |
1975年 | 14814篇 |
1974年 | 17426篇 |
1973年 | 16852篇 |
1972年 | 16016篇 |
1971年 | 14929篇 |
1970年 | 13886篇 |
1969年 | 13423篇 |
1968年 | 12574篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
Fady K. Baddoura Isam W. Nasr Barbara Wrobel Qi Li Nancy H. Ruddle Fadi G. Lakkis 《American journal of transplantation》2005,5(3):510-516
Lymphoid neogenesis is the process by which ectopic lymphoid accumulations that resemble lymph nodes arise in nonlymphoid tissues. Such lymphoid accumulations, known as tertiary lymphoid organs (TLO), are observed in chronic autoimmunity and they propagate immune pathology by setting up local antigen presenting sites. Whether lymphoid neogenesis occurs in transplanted organs and contributes to rejection is not well understood. To begin to address this question, we retrospectively analyzed 319 murine cardiac allografts for microscopic evidence of lymph-node-like structures. We found 78 allografts that had either classical TLO, characterized by discrete T- and B-cell zones and high endothelial venules (HEV) expressing peripheral node addressin (PNAd) (n = 34), or PNAd(+) HEV without organized lymphoid accumulations (n = 44). These changes were present in both short- and long-lived allografts and were invariably associated with rejection. Importantly, they occurred in 78% of allografts undergoing chronic rejection (n = 85) but in only 7% of allografts undergoing primarily acute rejection (n = 184). These findings indicate that, like autoimmunity, alloimmunity is associated with lymphoid neogenesis in the target organ and suggest a role for local T-cell activation in chronic allograft rejection. 相似文献
994.
U. Bolm-Audorff S. Brandenburg T. Brüning H. Dupuis R. Ellegast G. Elsner K. Franz H. Grasshoff V. Grosser L. Hanisch B. Hartmann E. Hartung K. G. Hering G. Heuchert M. Jäger J. Krämer Dr. A. Kranig E. Ludolph A. Luttmann A. Nienhaus W. Pieper K.-D. Pöhl T. Remé D. Riede G. Rompe K. Schäfer S. Schilling E. Schmitt F. Schröter A. Seidler M. Spallek M. Weber 《Trauma und Berufskrankheit》2005,7(3):211-252
Occupational diseases Nos. 2108 and 2110 correspond to intervertebral disc-related diseases of the lumbar spine from many years of carrying or lifting heavy loads, occupations in extreme postures of full flexion or oscillation of the whole body when seated, and which compel the cessation of all activities which are or could be the cause for the origin, exacerbation or recurrence of the disease. These occupational diseases came into force at the start of 1993, but there have been considerable problems in their implementation. The present Part I of the contribution is the result of the work of an interdisciplinary study group and contains medical criteria for the assessment of possibly strain-related clinical characteristics and the evaluation of other possible causes. Part II is to be published in Volume 4/2005 and will deal with questions related to forced cessation and to the assessment of the loss of earning ability. Agreement was reached in many areas related to the assessment of occupational claims. This should allow for evidence-based decision making in the future for the occupational diseases Nos. 2108 and 2110. 相似文献
995.
P. Nowakowski K. Ziaja T. Ludyga W. Kuczmik G. Biolik P. wik D. Ziaja 《Diseases of the esophagus》2007,20(4):358-360
Esophageus or gaster resection in patients with malignant disease is still a treatment of choice. It is obvious that each surgical procedure in these patients carries some possibility of complications. Esophageo-gastric or esophageo-jejuno anastomosis has a 4-27% frequency of fistula occurrence. All these result in 65% mortality in cases of poorer prognosis. The aim of this paper is not to present all types of complications but to objectively analyse the usefulness of the covered stent placement in the treatment of anastomotic fistulas. We present six patients who were treated for postoperative fistula of esophageo-gastric anastomosis (1 case) or esophageo-jejuno anastomosis (5 cases). All patients were treated with stapler suture for digestive tract reconstruction after malignancy removal during the primary surgical procedure. Signs and symptoms of suture leak between 5-8 days post-surgery were observed. Conservative therapy was not effective. Thus a new method of treatment was employed - covered stent placement. The procedure was performed under X-ray control. In all treated patients there was change for the better and quick reduction of secretion from the fistulas was observed. All patients were discharged from the department after several days and all had survived at 30 days follow-up. Covered esophageal stent placement seems to be a safe and promising method of treatment for patients with anastomotic fistula which significantly reduces mortality and improves quality of live. Our experiences confirms that of other investigators. 相似文献
996.
Michael Rosenzweig Martha Skinner Tatiana Prokaeva Roger Théberge Catherine Costello Brian M Drachman Lawreen H Connors 《Amyloid》2007,14(1):65-71
We report the identification of a new transthyretin (TTR) gene mutation and variant protein, Glu61Gly, in a 55-year-old man with progressive cardiomyopathy, mild peripheral neuropathy and bilateral carpal tunnel syndrome. A diagnosis of TTR-associated familial amyloidosis (ATTR) was considered after an endomyocardial biopsy revealed amyloid deposits in the heart of a patient who had no family history of amyloidosis and no evidence of a plasma cell dyscrasia. Serum screening for a TTR variant by isoelectric focusing (IEF) was positive and prompted further studies to identify the genetic abnormality and to characterize the amyloidogenic protein. Direct DNA sequence analysis of all four coding regions in the TTR gene demonstrated heterozygosity in exon 3. Near equal amounts of guanine (G) and adenine (A) were observed at the second base position of codon 61. The wild-type (GAG) and mutated (GGG) sequences found in codon 61 correspond to glutamic acid (Glu) and glycine (Gly) residues, amino acids which differ in mass by -72 Da. Mass spectrometric analyses of TTR immunoprecipitated from serum showed the presence of both wild-type and variant proteins. The observed mass results for the wild-type and variant proteins were consistent with the predicted values calculated from the genetic analysis data. 相似文献
997.
N Deb-Joardar N Germain G Thuret A -F Garcin P Manoli A Defreyn P Gain B Estour 《Diabetic medicine》2007,24(3):303-307
AIMS: Screening for diabetic retinopathy (DR) is highly inadequate in France because of insufficient infrastructure and increasing disease prevalence. We describe the results of the first systematic DR screening programme established in a university diabetes department. METHODS: In this cross-sectional study conducted over 1 year, consecutive adult patients underwent three-field retinal photography with the Topcon TRC NW6S digital fundus camera following pupillary dilatation with Tropicamide 1%. A questionnaire provided information on patients' systemic and ocular history. Glycated haemoglobin (HbA1c) was measured at the screening visit.Two ophthalmologists graded the retinal photographs in a masked fashion. RESULTS: Of 1157 patients attending the diabetes department, 1153 (99.7%)underwent photographic screening. Images were gradable in 96% patients.Diabetic retinopathy was detected in 522 (45%) patients and sight-threatening DR in 167 (14%). Of 704 (61%) patients previously believed to have no DR,254 (34%) screened positive. The presence of DR was associated with age,insulin use and non-Caucasian ethnicity in Type 2 patients, and with duration of diabetes and HbA1c in Type 1 and Type 2 patients. Associated ocular pathologies were diagnosed in 612 (53%) patients. CONCLUSIONS: Our photographic screening programme using pharmacological mydriasis provided a high screening coverage feasible in a hospital setting. We obtained information regarding prevalence and associated risk factors of DR inpatients attending a tertiary care centre. Screening was well accepted by patients and met with no protest from city ophthalmologists. It generated considerable interest among endocrinologists and feedback of results is expected to improve optimization of glycaemic control. 相似文献
998.
999.
1000.
Scott S Auerbach Joshua G Dekeyser Matthew A Stoner Curtis J Omiecinski 《Drug metabolism and disposition》2007,35(3):428-439
The constitutive androstane receptor (CAR; NR1I3) regulates the expression of genes involved in xenobiotic metabolism. Alternative splicing of the human CAR gene yields an array of mRNAs that encode structurally diverse proteins. One form of CAR, termed CAR2, contains an additional four amino acids (SPTV) that are predicted to reshape the ligand-binding pocket. The current studies show a marked, ligand-independent, CAR2-mediated transactivation of reporters containing optimal DR-3, DR-4, and DR-5 response elements, and reporters derived from the natural CYP2B6 and CYP3A4 gene promoters. Overexpression of the RXRalpha ligand binding domain was critical for achieving these effects. CAR2 interaction with SRC-1 was similarly dependent on the coexpression of RXRalpha. Mutagenesis of Ser233 (SPTV) to an alanine residue yielded a receptor possessing higher constitutive activity. Alternatively, mutating Ser233 to an aspartate residue drastically reduced the transactivation capacity of CAR2. The respective abilities of these mutagenized forms of CAR2 to transactivate a DR-4 x 3 reporter element correlated with their ability to interact with RxRalpha and to recruit SRC-1 in a ligand-regulated manner. Together, these results demonstrate a robust RXRalpha-dependent recruitment of coactivators and transactivation by CAR2. In addition, CAR2 displays novel dose responses to clotrimazole and androstanol compared with the reference form of the receptor while at the same time retaining the ability to bind CITCO. This result supports a hypothesis whereby the four-amino-acid insertion in CAR2 structurally modifies its ligand binding pocket, suggesting that CAR2 is regulated by a set of ligands distinct from those governing the activity of reference CAR. 相似文献