全文获取类型
收费全文 | 1106篇 |
免费 | 86篇 |
国内免费 | 59篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 51篇 |
妇产科学 | 15篇 |
基础医学 | 99篇 |
口腔科学 | 19篇 |
临床医学 | 169篇 |
内科学 | 280篇 |
皮肤病学 | 25篇 |
神经病学 | 35篇 |
特种医学 | 235篇 |
外科学 | 79篇 |
综合类 | 39篇 |
一般理论 | 1篇 |
预防医学 | 106篇 |
眼科学 | 12篇 |
药学 | 51篇 |
中国医学 | 2篇 |
肿瘤学 | 31篇 |
出版年
2022年 | 5篇 |
2021年 | 15篇 |
2020年 | 8篇 |
2019年 | 7篇 |
2018年 | 19篇 |
2017年 | 12篇 |
2016年 | 8篇 |
2015年 | 25篇 |
2014年 | 23篇 |
2013年 | 37篇 |
2012年 | 33篇 |
2011年 | 34篇 |
2010年 | 26篇 |
2009年 | 31篇 |
2008年 | 25篇 |
2007年 | 58篇 |
2006年 | 12篇 |
2005年 | 18篇 |
2004年 | 23篇 |
2003年 | 22篇 |
2002年 | 13篇 |
2001年 | 11篇 |
2000年 | 12篇 |
1999年 | 17篇 |
1998年 | 53篇 |
1997年 | 41篇 |
1996年 | 63篇 |
1995年 | 47篇 |
1994年 | 43篇 |
1993年 | 55篇 |
1992年 | 18篇 |
1991年 | 16篇 |
1990年 | 30篇 |
1989年 | 38篇 |
1988年 | 41篇 |
1987年 | 50篇 |
1986年 | 34篇 |
1985年 | 45篇 |
1984年 | 18篇 |
1983年 | 13篇 |
1982年 | 16篇 |
1981年 | 22篇 |
1980年 | 22篇 |
1979年 | 12篇 |
1978年 | 13篇 |
1977年 | 20篇 |
1976年 | 12篇 |
1975年 | 11篇 |
1972年 | 5篇 |
1971年 | 4篇 |
排序方式: 共有1251条查询结果,搜索用时 15 毫秒
41.
Identification of the multiple endocrine neoplasia type 1 (MEN1) gene. The European Consortium on MEN1 总被引:10,自引:0,他引:10
Lemmens I; Van de Ven WJ; Kas K; Zhang CX; Giraud S; Wautot V; Buisson N; De Witte K; Salandre J; Lenoir G; Pugeat M; Calender A; Parente F; Quincey D; Gaudray P; De Wit MJ; Lips CJ; Hoppener JW; Khodaei S; Grant AL; Weber G; Kytola S; Teh BT; Farnebo F; Thakker RV 《Human molecular genetics》1997,6(7):1177-1183
42.
43.
Fleischer AC; Dudley BS; Entman SS; Baxter JW; Kalemeris GC; James AE Jr 《Radiology》1987,162(2):307-310
The depth of myometrial invasion by endometrial carcinoma was evaluated using real-time sonography (US) in 20 patients with histologically proved adenocarcinoma of the endometrium. In 14 of 20 (70%) cases, US-based estimation of the depth of myometrial invasion was within 10% of the actual measurement in the gross specimen. The US-based estimation of tumor invasion was low in seven patients, high in four patients, and agreed with pathologic findings (+/- 5%) in nine patients. In four patients with polypoid intraluminal extension of tumor, a deeply invasive tumor was suspected on US but was not found on pathologic examination. In 12 superficially invasive tumors, the continuity of the demarcating subendometrial halo was intact in nine and incomplete in three. In six patients with deeply invasive tumors, this zone was partially disrupted in four, totally disrupted in one, and intact in one. Errors of estimation of the depth of myometrial invasion on US most frequently occurred when a tumor had a significant intraluminal polypoid extension. Demonstration of a subendometrial halo usually indicated superficial invasion, whereas the absence of a halo was frequently associated with deep invasion. 相似文献
44.
Insertion of a screw biopsy stylet into a thin-walled biopsy needle greatly enhances detection of the needle during ultrasound-guided percutaneous biopsy. This technique is helpful when precise needle-tip localization is needed for biopsies of small lesions. 相似文献
45.
Occlusion of varicoceles wih detachable balloons 总被引:1,自引:0,他引:1
46.
47.
Erythropoietin production in a primary culture of human renal carcinoma cells maintained in nude mice 总被引:4,自引:1,他引:4
The present studies report erythropoietin (Ep) production in primary cultures of a human renal carcinoma from a patient with erythrocytosis that has been serially transplanted to BALB/c nude mice. The levels of erythropoietin in the culture media were estimated using the exhypoxic polycythemic mouse assay (EHPCMA), fetal mouse liver erythroid colony- forming technique (FMLC), and a radioimmunoassay (RIA). The spent culture media of the exponentially growing cells contained less than 10 mU/ml of Ep measured by RIA. However, after the cells became confluent, Ep levels (RIA) in the spent media showed a marked increase to approximately 300 mU/ml. Ep levels estimated using the FMLC and EHPCMA were approximately 2/3 and 1/10, respectively, of those measured by RIA. Rabbit antiserum to highly purified human urinary Ep (70,400 U/mg protein) was utilized for immunocytochemical (peroxidase-antiperoxidase method) localization of Ep in the cultured cells. Very few of the cells in exponential growth exhibited Ep-like immunoreactivity, whereas intense Ep-like immunoreactivity was observed in the cytoplasm of the cells maintained in culture for a prolonged period after reaching confluency. The most intense staining was observed in some of the cells forming domes. The domes developed after the cells reached confluency, and their numbers increased with increasing time in confluent culture, in parallel with the increase in Ep levels in the spent media. This primary cell culture system of a renal cell carcinoma maintained in nude mice, which produces immunologically and biologically active Ep, may provide a useful model for studies of the mechanism of Ep production. 相似文献
48.
49.
Sixteen cases of histopathologically proved solitary rectal ulcer syndrome were encountered. Fifteen patients underwent barium enema study; in nine cases the findings--including rectal stricture, granularity of the mucosa, and thickened rectal folds-were nonspecific. In six cases the study was normal. All patients had a long history of defecation disorders, and defecography was performed in all. In seven cases, intussusception of the rectal wall was seen; in another case the intussusception was accompanied by a rectocele. One case showed rectal prolapse. In four cases, failed relaxation of the puborectalis occurred and prevented the passage of the bolus; in another case there was abnormal perineal descent. In two patients studies were normal. In patients with defecation disorders, the possibility of this syndrome should be considered. Defecography is the method of choice for establishing the diagnosis. 相似文献
50.
Short-Ti inversion-recovery pulse sequence: analysis and initial experience in cancer imaging 总被引:2,自引:0,他引:2
Inversion recovery (IR), commonly considered a pulse sequence capable of producing T1-weighted images with excellent display of normal anatomy, is versatile: The null point and peak time provide a useful, succinct summary of the properties of IR and its capacity for producing both T1- and T2-weighted images. Shortening of the inversion time (TI) and creation of a short-TI inversion-recovery (STIR) pulse sequence increases sensitivity to malignancy and other abnormalities by making the effects of prolonged T1 and T2 on signal intensity additive and by nulling the signal from fat. The authors examined over 300 patients with various malignancies and compared STIR images with T1- and T2-weighted images obtained at 0.5 T. In 43 cases, signal-difference-to-noise ratios (SD/Ns) were calculated between tumor, fat, and muscle. In general, STIR images demonstrated tumor as a conspicuously high-intensity area in a background of muted, discernible anatomic detail. The good contrast achieved with STIR sequences between tumor and fat (SD/N = 18.1) and tumor and muscle (SD/N = 12.9) consolidated into a single image the information contained separately on T1- and T2-weighted images, which facilitates efficient detection and localization of malignancy. 相似文献