全文获取类型
收费全文 | 1990篇 |
免费 | 93篇 |
国内免费 | 35篇 |
专业分类
耳鼻咽喉 | 18篇 |
儿科学 | 138篇 |
妇产科学 | 23篇 |
基础医学 | 312篇 |
口腔科学 | 48篇 |
临床医学 | 168篇 |
内科学 | 344篇 |
皮肤病学 | 74篇 |
神经病学 | 136篇 |
特种医学 | 246篇 |
外科学 | 174篇 |
综合类 | 44篇 |
预防医学 | 79篇 |
眼科学 | 129篇 |
药学 | 81篇 |
中国医学 | 3篇 |
肿瘤学 | 101篇 |
出版年
2022年 | 24篇 |
2021年 | 45篇 |
2020年 | 31篇 |
2019年 | 32篇 |
2018年 | 59篇 |
2017年 | 36篇 |
2016年 | 33篇 |
2015年 | 50篇 |
2014年 | 51篇 |
2013年 | 83篇 |
2012年 | 90篇 |
2011年 | 92篇 |
2010年 | 91篇 |
2009年 | 79篇 |
2008年 | 83篇 |
2007年 | 97篇 |
2006年 | 82篇 |
2005年 | 73篇 |
2004年 | 58篇 |
2003年 | 56篇 |
2002年 | 33篇 |
2001年 | 38篇 |
2000年 | 49篇 |
1999年 | 48篇 |
1998年 | 56篇 |
1997年 | 52篇 |
1996年 | 55篇 |
1995年 | 36篇 |
1994年 | 44篇 |
1993年 | 42篇 |
1992年 | 25篇 |
1991年 | 32篇 |
1990年 | 19篇 |
1989年 | 36篇 |
1988年 | 57篇 |
1987年 | 42篇 |
1986年 | 27篇 |
1985年 | 38篇 |
1984年 | 7篇 |
1983年 | 7篇 |
1982年 | 10篇 |
1981年 | 9篇 |
1980年 | 11篇 |
1979年 | 13篇 |
1977年 | 8篇 |
1976年 | 13篇 |
1975年 | 6篇 |
1973年 | 8篇 |
1972年 | 12篇 |
1971年 | 12篇 |
排序方式: 共有2118条查询结果,搜索用时 15 毫秒
151.
Isthmic spondylolysis of the lumbar spine: MR imaging at 1.5 T 总被引:4,自引:0,他引:4
The appearance on magnetic resonance (MR) images of the normal pars interarticularis in 13 patients was reviewed and contrasted with that of the pars in eight patients with spondylolysis. The pars defect usually had an intermediate signal intensity with all pulse sequences; however, this intensity was somewhat variable depending on the exact ratio of cartilage, fat, and fluid within each bone defect. The pars defect was best seen with spin-echo 600/20 (repetition time msec/echo time msec) images. In three cases, out-of-phase images showed the spondylolysis best, because of extension of fat to the borders of the defect. The sagittal view allowed one to separate spondylolysis from the joint space of posterior facets since the orientation of the defects is perpendicular to the facets; thus, a common pitfall encountered with cross-sectional axial imaging techniques is avoided. MR imaging poorly delineated bone fragments around the defect, which may produce nerve root impingement, but revealed other numerous complications that occur with spondylolysis, including spondylolisthesis and herniation of the disk above. 相似文献
152.
153.
Transabdominal and endovaginal pelvic sonograms were obtained in 108 nonpregnant patients referred for pelvic sonography. The studies were independently obtained by two radiologists and interpreted on the basis of identical clinical information. The sonograms were then compared for anatomic detail and abnormalities. A determination was made about which examination, if either, was superior. Follow-up was performed through a review of the medical records and follow-up studies. Overall, the endovaginal study was judged superior in 65 cases (60.2%), equal in 39 (36.1%), and inferior in four (3.7%). The authors conclude that the endovaginal examination can effectively replace the transabdominal examination as the initial approach for routine pelvic sonography. 相似文献
154.
155.
Williamson MR; Boyd CM; McGuire EL; Angtuaco T; Westbrook KC; Lang NP; Alston J; Broadwater JR; Navab F; Bersey ML 《Radiology》1986,159(1):272-273
The nuclear medicine bleeding scan is frequently insufficient to locate sites of bleeding precisely, in spite of its great sensitivity. A small, hand-held Geiger-Müller counter, placed directly on exposed intestine in the operating room, enables precise location of the probable bleeding site. In three patients, the technique allowed a minimal amount of intestine to be resected, distinguished between large- and small-intestinal hemorrhage, and eliminated other foci as sites of bleeding. 相似文献
156.
Chopra H Khurana A. S. Malhotra U. Mathur N. Sidhu U. S. 《Indian journal of otolaryngology and head and neck surgery》2000,52(4):364-365
This study was undertaken to study early and late post extubation complications following endotracheal intubation and tracheostomy.
A total 60 patients who were admitted in Dayanand Medical College and Hospital were studied prospectively. They were divided
into 3 groups and were screened with various modalities like fiberoptic laryngoscopy. Bronchoscope, X-Ray Soft Tissue Neck
and CT Scan, Complications like glottic edema, vocal tears, vocal granuhmas and tracheal stenosis were seen and were accordingly
managed. 相似文献
157.
Liu J Zheng BS Aposhian HV Zhou YS Chen ML Zhang AH Waalkes MP. 《Journal of the peripheral nervous system : JPNS》2002,7(3):208-208
Optimization of a previously disclosed sorbitol dehydrogenase inhibitor (SDI, II) for potency and duration of action was achieved by replacing the metabolically labile N,N-dimethylsulfamoyl group with a variety of heterocycles. Specifically, this effort led to a series of novel, in vitro potent SDIs with longer serum half-lives and acceptable in vivo activity in acutely diabetic rats (e.g., 62, 67, and 69). However, the desired in vivo potency in chronically diabetic rats, ED90 less than or equal to 5 mg/kg/day, was achieved only through further modification of the piperazine linker. Several members of this family, including 86, showed better than the targeted potency with ED90 values of 1-2 mg/kg/day. Compound 86 was further profiled and found to be a selective inhibitor of sorbitol dehydrogenase, with excellent pharmacodynamic/pharmacokinetic properties, demonstrating normalization of sciatic nerve fructose in a chronically diabetic rat model for approximately 17 h, when administered orally at a single dose of 2 mg/kg/day. 相似文献
158.
159.
S Paeschke N Horn C Fotopoulou A Zambon-Bertoja A Sollwedel ML Zenclussen P Casalis J Dudenhausen HD Volk F Chen A Zenclussen 《American journal of reproductive immunology (New York, N.Y. : 1989)》2005,54(2):120-121
The acceptance of the semiallogeneic fetus within the maternal environment requires tolerance mechanisms not fully characterized yet. Normal pregnancy is known to be associated with a Th2 profile. Furthermore, T-regulatory cells were proposed to regulate the Th2/Th1 balance at early stages of pregnancy. Treg may avoid the shift to a Th1 profile preventing miscarriage. Accordingly, spontaneous abortion is characterized by a Th1 dominance and diminished levels of Tregulatory cells (Treg). The major aim of the present work was to investigate if pre-eclampsia, a late immunological complication of pregnancy, is characterized by similar hallmarks. Therefore, we measured the surface antigens CD4, CD25, CD8, CTLA4 (as well as the secretion of IL-10) in peripheral blood from patients suffering from pre-eclampsia (n = 8) and age-matched patients undergoing normal pregnancies (n = 9) by 4-colour flow-cytometry. We were not able to find any significant differences in the levels of CD4+ , CD25+ , CD8+ , CTLA4, CD4+ /CD25+ , CD4+ /CD25bright , CD4+ /CTLA4, CD25+ /CTLA4, CD4+ /CD25+ /CTLA4, CD8+ /CD25+ , CD8+ /CTLA4 or CD8+ /CD25+ /CTLA4 cell subsets. Our data suggest that Treg may not participate in the onset of pre-eclampsia and suggest other regulatory mechanisms during late pregnancy. 相似文献
160.