全文获取类型
收费全文 | 5122篇 |
免费 | 403篇 |
国内免费 | 21篇 |
专业分类
耳鼻咽喉 | 28篇 |
儿科学 | 99篇 |
妇产科学 | 134篇 |
基础医学 | 599篇 |
口腔科学 | 92篇 |
临床医学 | 566篇 |
内科学 | 1116篇 |
皮肤病学 | 55篇 |
神经病学 | 358篇 |
特种医学 | 174篇 |
外国民族医学 | 1篇 |
外科学 | 1081篇 |
综合类 | 88篇 |
一般理论 | 3篇 |
预防医学 | 303篇 |
眼科学 | 161篇 |
药学 | 295篇 |
中国医学 | 14篇 |
肿瘤学 | 379篇 |
出版年
2023年 | 46篇 |
2022年 | 109篇 |
2021年 | 201篇 |
2020年 | 101篇 |
2019年 | 166篇 |
2018年 | 176篇 |
2017年 | 154篇 |
2016年 | 149篇 |
2015年 | 167篇 |
2014年 | 234篇 |
2013年 | 262篇 |
2012年 | 440篇 |
2011年 | 424篇 |
2010年 | 217篇 |
2009年 | 181篇 |
2008年 | 280篇 |
2007年 | 265篇 |
2006年 | 283篇 |
2005年 | 272篇 |
2004年 | 225篇 |
2003年 | 232篇 |
2002年 | 196篇 |
2001年 | 72篇 |
2000年 | 66篇 |
1999年 | 57篇 |
1998年 | 37篇 |
1997年 | 26篇 |
1996年 | 23篇 |
1995年 | 21篇 |
1994年 | 15篇 |
1993年 | 13篇 |
1992年 | 38篇 |
1991年 | 29篇 |
1990年 | 27篇 |
1989年 | 28篇 |
1988年 | 21篇 |
1987年 | 17篇 |
1986年 | 15篇 |
1985年 | 14篇 |
1984年 | 19篇 |
1983年 | 15篇 |
1982年 | 14篇 |
1980年 | 11篇 |
1979年 | 14篇 |
1978年 | 11篇 |
1977年 | 13篇 |
1976年 | 15篇 |
1973年 | 13篇 |
1972年 | 25篇 |
1971年 | 21篇 |
排序方式: 共有5546条查询结果,搜索用时 15 毫秒
61.
Marco?Moschini Beat?Foerster Mohammad?Abufaraj Francesco?Soria Thomas?Seisen Morgan?Roupret Pierre?Colin Alexandre?De la?Taille Benoit?Peyronnet Karim?Bensalah Roman?Herout Manfred?Peter?Wirth Vladimir?Novotny Piotr?Chlosta Marco?Bandini Francesco?Montorsi Giuseppe?Simone Michele?Gallucci Giuseppe?Romeo Kazumasa?Matsumoto Pierre?Karakiewicz Alberto?Briganti Shahrokh?F.?Shariat
Introduction
To evaluate temporal trends in the delivery and extent of lymphadenectomy (LND) in radical nephroureterectomy (RNU) performed in upper tract urothelial carcinoma (UTUC) patients.Methods
We evaluated a multi institutional collaborative database composed by 1512 consecutive patients diagnosed with UTUC treated with RNU between 1990 and 2016. Year of surgery were grouped in five periods: 1990–1996, 1997–2002, 2003–2007, 2008–2012 and 2013–2016. Data about LND were available for all patients and numbers of nodes removed and positive were reported by dedicate uropathologists. The Mann–Whitney and Chi square tests were used to compare the statistical significance of differences in medians and proportions, respectively.Results
Five hundred forty-five patients (36.0%) received a concomitant LND while 967 (64.0%) did not; 41.9% of open RNU patients received a concomitant LND compared to 24.4% of laparoscopic RNU patients. The rate of concomitant LND increased with time in the overall, laparoscopic and open RNU patients (all p?<?0.03). Patients treated with open RNU also had an increasing likelihood to receive an adequate concomitant LND (p?<?0.001) while those undergoing a laparoscopic approach did not (p?=?0.1). Patients treated with concomitant LND had a median longer operative time of 20 min (p?=?0.01). There were no differences in perioperative outcomes and complications between patients who received a concomitant LND and those who did not (p?>?0.1).Conclusion
Although an increased trend was observed, most patients treated with RNU did not receive LND. Surgeons using a laparoscopic RNU were less likely to perform a concomitant LND, and when done, they remove less nodes.62.
Franklin D. Gaylis Jae E. Choi Zachary Hamilton Paul Dato Edward Cohen Renee Calabrese Hilary Prime Aaron Rosenbaum Andrew Karim Kader 《Urologic oncology》2017,35(11):663.e1-663.e7
Objective
The benefits of prostate-specific antigen (PSA)–based prostate cancer screening are controversial. We sought to determine the change in prostate cancer presentation coinciding with the release of the United States Preventative Services Task Force recommendations against screening in a high-volume community-based urology practice.Methods
Characteristics of men presenting for an elevated PSA at a community urology practice from August 2011 to August 2015 were queried from a prospectively collected database. A retrospective analysis of presenting PSA, Gleason grade at biopsy, and prostatectomy as well as clinical and pathologic stage was performed. Kruskal-Wallis rank sum and chi-square tests were used for analysis.Results
Referrals for elevated PSA decreased from 933 in year 1 to 816 by year 4 (12.5% decrease) with a concomitant reduction in biopsies performed in newly referred men from 461 to 356 (22.8% decrease, P = 0.02). The proportion of men presenting with PSAs>10 increased from 28.1% to 36.8% (P = 0.009). First-time biopsy-positivity rate increased from 48.4% to 62.4% with a rise in the proportion having Gleason≥7 from 51.6% to 69.7% (P = 0.0001). Of the 578 men who underwent radical prostatectomy, there was a 19.4% increase in Gleason≥7 tumors (P = 0.01).Conclusions
Our findings demonstrate a decrease in elevated PSA referrals, increase in PSA at the time of referral, decrease in detection of low-risk disease, and increase in detection of intermediate-/high-risk disease in a high-volume, multisite, community-based urology practice, coinciding with the United States Preventative Services Task Force recommendations against PSA screening. 相似文献63.
64.
Technical feasibility and safety of image‐guided parieto‐occipital ventricular catheter placement with the assistance of a wearable head‐up display 下载免费PDF全文
65.
Impact of Calcium and Two Doses of Vitamin D on Bone Metabolism in the Elderly: A Randomized Controlled Trial 下载免费PDF全文
Maya Rahme Sima Lynn Sharara Rafic Baddoura Robert H Habib Georges Halaby Asma Arabi Ravinder J Singh Moustapha Kassem Ziyad Mahfoud Maha Hoteit Rose T Daher Darina Bassil Karim El Ferkh Ghada El‐Hajj Fuleihan 《Journal of bone and mineral research》2017,32(7):1486-1495
The optimal dose of vitamin D to optimize bone metabolism in the elderly is unclear. We tested the hypothesis that vitamin D, at a dose higher than recommended by the Institute of Medicine (IOM), has a beneficial effect on bone remodeling and mass. In this double‐blind trial we randomized 257 overweight elderly subjects to receive 1000 mg of elemental calcium citrate/day, and the daily equivalent of 3750 IU/day or 600 IU/day of vitamin D3 for 1 year. The subjects’ mean age was 71 ± 4 years, body mass index 30 ± 4 kg/m2, 55% were women, and 222 completed the 12‐month follow‐up. Mean serum 25 hydroxyvitamin D (25OHD) was 20 ng/mL, and rose to 26 ng/mL in the low‐dose arm, and 36 ng/mL in the high‐dose arm, at 1 year (p < 0.05). Plasma parathyroid hormone, osteocalcin, and C‐terminal telopeptide (Cross Laps) levels decreased significantly by 20% to 22% in both arms, but there were no differences between the two groups for any variable, at 6 or 12 months, with the exception of serum calcitriol, which was higher in the high‐dose group at 12 months. Bone mineral density (BMD) increased significantly at the total hip and lumbar spine, but not the femoral neck, in both study arms, whereas subtotal body BMD increased in the high‐dose group only, at 1 year. However, there were no significant differences in percent change BMD between the two study arms at any skeletal site. Subjects with serum 25OHD <20 ng/mL and PTH level >76 pg/mL showed a trend for higher BMD increments at all skeletal sites, in the high‐dose group, that reached significance at the hip. Adverse events were comparable in the two study arms. This controlled trial shows little additional benefit in vitamin D supplementation at a dose exceeding the IOM recommendation of 600 IU/day on BMD and bone markers, in overweight elderly individuals. © 2017 American Society for Bone and Mineral Research. 相似文献
66.
MRI assessment of tissue effects after 180‐W XPS greenlight laser vaporization of the prostate 下载免费PDF全文
67.
We conducted an observational cross-sectional study to determine if the prevalence of hematologic and metabolic abnormalities in chronic kidney disease (CKD) varied in different ethnic groups. We used a CKD provincial database where a complete data set at the time of registration was available as well as an estimated glomerular filtration rate (eGFR), which showed using the abbreviated MDRD formula that the patients had CKD of stages 3-5. We included patients with self-reported race of Caucasian, Oriental Asian, or South Asian. Primary outcomes were the prevalence of at least one of the following: anemia, hypocalcemia, hyperphosphatemia, hyperparathyroidism, hypoalbuminemia, and three or more laboratory abnormalities. All definitions were consistent with K/DOQI guidelines. When compared with Caucasians, Oriental Asians and South Asians had a higher prevalence of many of the metabolic abnormalities during most stages of CKD and were more likely to have any abnormality at all levels of eGFR. The prevalence of three or more laboratory abnormalities was higher in Oriental Asians at all stages and in South Asians at some levels of eGFR. These results were unchanged or exaggerated when controlled for age, gender, diabetes, and a primary diagnosis of renal disease. Hence, it appears that South Asians and Oriental Asians have more laboratory abnormalities compared with Caucasians at most levels of eGFR. 相似文献
68.
Examining bone surfaces across puberty: a 20-month pQCT trial. 总被引:2,自引:0,他引:2
Saija A Kontulainen Heather M Macdonald Karim M Khan Heather A McKay 《Journal of bone and mineral research》2005,20(7):1202-1207
This follow-up study assessed sex differences in cortical bone growth at the tibial midshaft across puberty. In both sexes, periosteal apposition dominated over endosteal resorption. Boys had a greater magnitude of change at both surfaces, and thus, a greater increase in bone size across puberty. Relative increase in cortical bone area was similar between sexes. INTRODUCTION: Generally, sex differences in bone size become most evident as puberty progresses. This was thought to be caused, in part, by greater periosteal apposition in boys, whereas endosteal apposition prevailed in girls. However, this premise is based on evidence from cross-sectional studies and planar measurement techniques. Thus, our aim was to prospectively evaluate sex-specific changes in cortical bone area across puberty. MATERIALS AND METHODS: We used pQCT to assess the tibial midshaft (50% site) at baseline and final (20 months) in girls (N = 68) and boys (N = 60) across early-, peri-, and postpuberty. We report total bone cross-sectional area (ToA, mm2), cortical area (CoA, mm2), marrow cavity area (CavA, mm2), and CoA/ToA ratio. RESULTS: Children were a mean age of 11.9 +/- 0.6 (SD) years at baseline. At the tibia, CoA ranged from 230 +/- 44, 261 +/- 50, and 258 +/- 46 in early-, peri-, and postpubertal girls. In boys, comparable values were 223 +/- 36 (early), 264 +/- 38 (peri), and 281 +/- 77 (postpubertal). There was no sex difference for ToA or CoA at baseline. Increase in ToA and CoA was, on average, 10% greater for boys than girls across maturity groups. The area of the marrow cavity increased in all groups, but with considerable variability. The increase in CavA was significantly less for girls than boys in the early- and postpubertal groups. Change in CoA/ToA was similar between sexes across puberty. CONCLUSION: Both sexes showed a similar pattern of change in CoA at the tibial midshaft, where periosteal apposition dominated over endosteal resorption. Boys showed a greater magnitude of change at both surfaces, and thus, showed a greater increase in bone size across puberty. The relative increase in cortical area was similar between sexes. These pQCT findings provide no evidence for endosteal apposition in postmenarchal girls. 相似文献
69.
70.
Plomgaard P Bouzakri K Krogh-Madsen R Mittendorfer B Zierath JR Pedersen BK 《Diabetes》2005,54(10):2939-2945
Most lifestyle-related chronic diseases are characterized by low-grade systemic inflammation and insulin resistance. Excessive tumor necrosis factor-alpha (TNF-alpha) concentrations have been implicated in the development of insulin resistance, but direct evidence in humans is lacking. Here, we demonstrate that TNF-alpha infusion in healthy humans induces insulin resistance in skeletal muscle, without effect on endogenous glucose production, as estimated by a combined euglycemic insulin clamp and stable isotope tracer method. TNF-alpha directly impairs glucose uptake and metabolism by altering insulin signal transduction. TNF-alpha infusion increases phosphorylation of p70 S6 kinase, extracellular signal-regulated kinase-1/2, and c-Jun NH(2)-terminal kinase, concomitant with increased serine and reduced tyrosine phosphorylation of insulin receptor substrate-1. These signaling effects are associated with impaired phosphorylation of Akt substrate 160, the most proximal step identified in the canonical insulin signaling cascade regulating GLUT4 translocation and glucose uptake. Thus, excessive concentrations of TNF-alpha negatively regulate insulin signaling and whole-body glucose uptake in humans. Our results provide a molecular link between low-grade systemic inflammation and the metabolic syndrome. 相似文献