全文获取类型
收费全文 | 5362篇 |
免费 | 554篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 31篇 |
儿科学 | 151篇 |
妇产科学 | 104篇 |
基础医学 | 688篇 |
口腔科学 | 112篇 |
临床医学 | 620篇 |
内科学 | 1241篇 |
皮肤病学 | 78篇 |
神经病学 | 466篇 |
特种医学 | 201篇 |
外科学 | 720篇 |
综合类 | 19篇 |
一般理论 | 3篇 |
预防医学 | 468篇 |
眼科学 | 132篇 |
药学 | 437篇 |
中国医学 | 2篇 |
肿瘤学 | 451篇 |
出版年
2024年 | 17篇 |
2023年 | 118篇 |
2022年 | 66篇 |
2021年 | 167篇 |
2020年 | 182篇 |
2019年 | 178篇 |
2018年 | 289篇 |
2017年 | 281篇 |
2016年 | 279篇 |
2015年 | 232篇 |
2014年 | 266篇 |
2013年 | 459篇 |
2012年 | 536篇 |
2011年 | 521篇 |
2010年 | 229篇 |
2009年 | 156篇 |
2008年 | 221篇 |
2007年 | 196篇 |
2006年 | 200篇 |
2005年 | 153篇 |
2004年 | 130篇 |
2003年 | 116篇 |
2002年 | 102篇 |
2001年 | 56篇 |
2000年 | 53篇 |
1999年 | 59篇 |
1998年 | 51篇 |
1997年 | 40篇 |
1996年 | 45篇 |
1995年 | 34篇 |
1994年 | 35篇 |
1993年 | 20篇 |
1992年 | 26篇 |
1991年 | 39篇 |
1990年 | 36篇 |
1989年 | 22篇 |
1988年 | 32篇 |
1987年 | 32篇 |
1986年 | 25篇 |
1985年 | 39篇 |
1984年 | 32篇 |
1983年 | 16篇 |
1982年 | 12篇 |
1981年 | 16篇 |
1980年 | 10篇 |
1979年 | 11篇 |
1978年 | 12篇 |
1977年 | 14篇 |
1976年 | 7篇 |
1969年 | 6篇 |
排序方式: 共有5924条查询结果,搜索用时 34 毫秒
991.
992.
MRI with an endorectal coil for staging of clinically localised prostate cancer prior to radical prostatectomy 总被引:2,自引:0,他引:2
J. Rørvik O. J. Halvorsen G. Albrektsen L. Ersland L. Dæhlin S. Haukaas 《European radiology》1999,9(1):29-34
The purpose of this study was to evaluate the ability of MR imaging with an endorectal coil (erMRI) to predict the local
pathological stage of prostatic carcinoma prior to radical prostatectomy. Thirty-one consecutive patients (median age 61 years,
range 40–71 years) with clinically localised prostate cancer were assessed preoperatively by endorectal MRI (at 1.0 T). The
pulse sequences consisted of fast spin-echo axial and coronal T2-weighted images and inversion recovery with two echoes for
axial fat-suppressed images. The assessment of tumour stage and measurement of tumour dimension by erMRI were compared with
the corresponding findings on whole-mount step sections of the surgical specimens. Postoperatively, 14 of the 31 patients
(45 %) were found to have extracapsular extension, 7 with capsular penetration (CP) only, and 7 had a combination of CP and
seminal vesicle invasion (SVI). Capsular penetration was detected by erMRI with a sensitivity of 0.71 and specificity of 0.47,
whereas the sensitivity for SVI detection was 0.71 and the specificity 0.83. Endorectal MRI for staging clinically localised
prostatic carcinoma gives a good prediction of invasion of the seminal vesicles but is unreliable in predicting capsular penetration.
Received: 25 November 1997; Revision received: 8 April 1998; Accepted: 8 May 1998 相似文献
993.
Presentation of cytosolic glycosylated peptides by human class I major histocompatibility complex molecules in vivo. 总被引:1,自引:0,他引:1
John S. Haurum Ingelise Bjerring H?ier Gemma Arsequell Anne Neisig Gregorio Valencia Jesper Zeuthen Jacques Neefjes Tim Elliott 《The Journal of experimental medicine》1999,190(1):145-150
Antigens presented by class I major histocompatibility complex (MHC) molecules for recognition by cytotoxic T lymphocytes consist of 8-10-amino-acid-long cytosolic peptides. It is not known whether posttranslationally modified peptides are also presented by class I MHC molecules in vivo. Many different posttranslational modifications occur on cytoplasmic proteins, including a cytosolic O-beta-linked glycosylation of serine and threonine residues with N-acetylglucosamine (GlcNAc). Using synthetic glycopeptides carrying the monosaccharide O-beta-GlcNAc substitution on serine residues, we have shown that glycopeptides bind efficiently to class I MHC molecules and elicit a glycopeptide-specific cytotoxic T lymphocyte response in mice. In this study, we provide evidence that peptides presented by human class I MHC molecules in vivo encompass a small, significant amount of glycopeptides, constituting up to 0.1% of total peptide. Furthermore, we find that carbohydrate structures present on glycopeptides isolated from class I MHC molecules are dominated by the cytosolic O-beta-GlcNAc substitution, and synthetic peptides carrying this substitution are efficiently transported by TAP (transporter associated with antigen presentation) into the endoplasmic reticulum. Thus, in addition to unmodified peptides, posttranslationally modified cytosolic peptides carrying O-beta-linked GlcNAc can be presented by class I MHC molecules to the immune system. 相似文献
994.
F. B. Christensen M. Lind S. P. Eiskjær K. Thomsen E. S. Hansen C. E. Bünger 《European spine journal》1999,8(1):54-60
The capacity of the individual patient to initiate osteoblast proliferation as a predictor for successful lumbar spinal fusion
has not yet been reported. The objectives of this study were, first, to analyze the relationship between in vitro osteoblast
proliferation and clinical bony fusion in the individual patient in order to predict the fusion outcome and, second, to measure
the effect of preoperative tobacco smoking on osteoblast proliferation. Sixty-one patients (mean age 46 years) underwent posterolateral
lumbar fusion in the period 1994–1995. Thirty-eight patients received CD pedicle screw implants and 23 received posterolateral
fusions alone. During surgery, autogenous iliac bone was harvested and 1 g of trabecular bone without blood or bone marrow
was then isolated for cell culturing. The cultures were classified as excellent (confluence within 4 weeks), good (confluence
between 4 and 6 weeks) and poor (no or poor growth). Spine fusion was evaluated by two independent observers from plain anterior-posterior,
lateral, and flexion/extension radiographs taken 1 year postoperatively, and the functional outcome was measured by the Dallas
Pain Questionnaire (DPQ). Twenty-three patients had excellent, 19 good, and 19 poor in vitro osteoblast proliferation. Bony
fusion was obtained in 77% of patients: 83% in the CD instrumentation group and 70% in the non-instrumentation group (NS).
There was no significant correlation between osteoblast proliferation and spinal fusion or functional outcomes when analyzing
the CD instrumentation and non-instrumentation groups together or separately. Elderly patients had a significantly poorer
osteoblast proliferation than younger patients (P < 0.008). Preoperative tobacco consumption had no discernible effect on osteoblast proliferation, and no correlation between
smoking and fusion was found. Further refinement of autologous osteoblast culturing may provide a biological tool for selection
of patients who require biological enhancement of their bone fusion capacity. The poorer osteoblast proliferation related
to advanced age supports the important negative biological influence of age on bony fusion. However, with more sensitive testing
and better discrimination, other results are possible – or can in any event not be excluded.
Received: 17 April 1998 Revised: 10 September 1998 Accepted: 12 October 1998 相似文献
995.
Three-Year Results of Laparoscopic Vertical Banded Gastroplasty 总被引:2,自引:0,他引:2
Erik Näslund MD PhD Jacob Freedman MD Jesper Lagergren MD PhD Dag Stockeld MD Lars Granström MD PhD 《Obesity surgery》1999,9(4):369-373
Background: Despite the development of pharmacologic agents for the treatment of massive obesity, surgery remains the only
treatment option that has been shown to offer long-term weight reduction. Laparoscopic surgery appears to offer rapid recovery
and low postoperative morbidity. The aim of the present study was to assess the outcome of laparoscopic vertical banded gastroplasty
(lap VBG) in 60 obese patients. Patients and Methods: 60 massively obese patients (50 female) with a mean ± SEM body mass
index (BMI) of 44.4 ± 1.0 kg/m2 were followed up prospectively for an average of 23.0 ± 1.5 months. Lap VBG was performed using 5 trocars placed in a standard
fashion for laparoscopic upper gastrointestinal surgery. A 4-row stapler was used for the vertical staple-line, and a stretched
polytetrafluoroethylene (Gore-Tex) band was used to reinforce the outlet. The patients were seen postoperatively 2, 6, 12,
24, and 36 months after surgery. Results: Conversion to open surgery was performed in 15 cases. Preoperative median BMI and
postoperative hospital stay were higher in the open group than in the laparoscopic group: 47.8 kg/m2 (37.7-65.7) and 5 days (3-13), and 41.9 kg/m2 (32.5-57.3) and 3 days (2-6), respectively (P < 0.01 for both). After 36 months of follow-up, the median BMI was 36.9 kg/m2 (24.6-50.7) (n = 9) in the open group and 37.0 kg/m2 (25.8-53.3) (n = 14) (NS) in the laparoscopic group. The number of conversions to open surgery and the median operating time
were higher in the first 30 cases than in the last 30 cases: 11 and 137.5 min (96-225) and 4 and 115.0 min (85-190), respectively,
with similar preoperative BMI: 44.1 kg/m2 (33.8-65.8) and 41.2 kg/m2 (32.4-57.8). Conclusions: Lap VBG can be performed safely and results in a shorter postoperative stay than does open surgery.
Weight loss was maintained over the 3-year follow-up period. There is a learning curve, resulting in fewer conversions to
open surgery and shorter operating time. Long follow-up studies are needed to ascertain that long-term weight loss equals
that of open VBG. 相似文献
996.
997.
U.B. Hartling B. Fischer Hansen L.T. Skovgaard I. Kjær 《American journal of medical genetics. Part A》2001,99(2):154-158
Prenatal standards of bi‐iliac width were not found in the literature based on autopsy investigations, nor was the caudo‐cranial position of the ilia compared to the vertebral column. The first purpose of the present study was to establish normal standard values for the bi‐iliac distance in fetal life, the second to evaluate the level of the iliac bones proportional to the ossified vertebral column. Whole body radiographs in antero‐posterior projections from 98 human fetuses (36 female and 44 male fetuses, as well as 18 fetuses on which the sex had not been determined) were analyzed in the study. The fetuses derived from spontaneous or induced abortions and they were radiographed as part of the required autopsy procedure. The crown‐rump‐length (CRL) of the fetuses varied from 32 to 245 mm. The outer and inner bi‐iliac distance was measured from the radiographs with a digital Helios slide caliper. The caudo‐cranial position of the iliac bones was evaluated. The present study shows that in normal fetal development there is a continuous linear enlargement of the pelvic region in the transverse and vertical planes. The upper iliac contour stays at the level of the first sacral vertebral body, whereas the lower iliac line moves caudally. Significant differences between male and female fetuses were not found. The value of the present study is that the results can be used as reference standards in prenatal pathology. © 2001 Wiley‐Liss, Inc. 相似文献
998.
999.
1000.
PURPOSE: To examine and compare the diagnostic accuracy of retinal nerve fibre layer (RNFL) thickness measurements using different Stratus optical coherence tomography (OCT) scanning protocols. METHODS: Stratus OCT data for 90 healthy subjects and 62 glaucoma patients with mild or moderate visual field loss were prospectively collected and analysed using four RNFL thickness protocols that differed in terms of image resolution and number of scans. Cut-off levels corrected for age and refractive error were defined by reference values derived from an independent normal database. Sensitivity and specificity were calculated for average RNFL thickness for the full circle scan, and for the quadrant and clock hour circle scan sectors at p < 5% and p < 1% cut-off values. RESULTS: Regular- and high-resolution images performed equally well, and single best-quality scans were as good as the average of three scans to distinguish between healthy and glaucomatous eyes. Full circle RNFL thickness yielded similar or better diagnostic accuracy than that of sectors. Sensitivities ranged from 84% to 87% and specificities from 89% to 93% for full circle RNFL thickness at the p < 5% cut-off level. CONCLUSIONS: The abilities of four different Stratus OCT RNFL thickness protocols to distinguish between eyes with predominantly mild glaucomatous field loss and healthy eyes were very similar. Thus diagnostic accuracy did not differ between high- and regular-resolution protocols, nor between global (full circle) and localized (sector) OCT parameters, which suggests a diffuse component in early glaucomatous RNFL damage. 相似文献