全文获取类型
收费全文 | 8820篇 |
免费 | 850篇 |
国内免费 | 38篇 |
专业分类
耳鼻咽喉 | 212篇 |
儿科学 | 211篇 |
妇产科学 | 380篇 |
基础医学 | 887篇 |
口腔科学 | 173篇 |
临床医学 | 819篇 |
内科学 | 1937篇 |
皮肤病学 | 218篇 |
神经病学 | 746篇 |
特种医学 | 523篇 |
外国民族医学 | 2篇 |
外科学 | 1463篇 |
综合类 | 120篇 |
一般理论 | 3篇 |
预防医学 | 681篇 |
眼科学 | 269篇 |
药学 | 361篇 |
中国医学 | 4篇 |
肿瘤学 | 699篇 |
出版年
2021年 | 77篇 |
2019年 | 98篇 |
2018年 | 111篇 |
2017年 | 94篇 |
2016年 | 117篇 |
2015年 | 126篇 |
2014年 | 171篇 |
2013年 | 239篇 |
2012年 | 328篇 |
2011年 | 353篇 |
2010年 | 210篇 |
2009年 | 176篇 |
2008年 | 303篇 |
2007年 | 345篇 |
2006年 | 389篇 |
2005年 | 344篇 |
2004年 | 320篇 |
2003年 | 335篇 |
2002年 | 289篇 |
2001年 | 267篇 |
2000年 | 319篇 |
1999年 | 277篇 |
1998年 | 110篇 |
1997年 | 85篇 |
1996年 | 92篇 |
1995年 | 87篇 |
1994年 | 85篇 |
1993年 | 75篇 |
1992年 | 221篇 |
1991年 | 233篇 |
1990年 | 234篇 |
1989年 | 215篇 |
1988年 | 196篇 |
1987年 | 191篇 |
1986年 | 207篇 |
1985年 | 210篇 |
1984年 | 139篇 |
1983年 | 135篇 |
1982年 | 94篇 |
1981年 | 91篇 |
1980年 | 81篇 |
1979年 | 155篇 |
1978年 | 107篇 |
1977年 | 112篇 |
1976年 | 95篇 |
1975年 | 105篇 |
1974年 | 129篇 |
1973年 | 109篇 |
1972年 | 97篇 |
1971年 | 74篇 |
排序方式: 共有9708条查询结果,搜索用时 0 毫秒
1.
2.
3.
4.
5.
C. M. Gordon E. Binello M. S. LeBoff M. E. Wohl C. J. Rosen A. A. Colin 《Osteoporosis international》2006,17(5):783-790
Introduction Patients with cystic fibrosis (CF) are known to be at risk for early osteoporosis, and the mechanisms that mediate bone loss
are still being delineated. The aim of the present investigation was to investigate if a correlation exists in these patients
between skeletal measurements by dual-energy x-ray absorptiometry (DXA) and two anabolic factors, dehydroepiandrosterone (DHEA)
and insulin-like growth factor I (IGF-I), and proresorptive factors such as the cytokines interleukin-1β, tumor necrosis factor α,
and interleukin-6.
Methods We studied 32 outpatients (18 females; mean age: 26.2 ± 7.9 years) at a tertiary care medical center. The subjects had venous
samples obtained, underwent anthropometric and bone mineral density (BMD) measurements, and completed a health survey. Serum
IGF-I concentrations were below the age-adjusted mean in 78% of the participants, and DHEA sulfate (DHEAS) concentrations
were low in 72%. Serum concentrations of all cytokines were on the low side of normal; nonetheless, there was a modest inverse
correlation between IL-1β and BMD at all sites.
Results In univariate analyses, IGF-I and DHEAS were significant correlates of BMD or bone mineral content. In final multivariate
models controlling for anthropometric and other variables of relevance to bone density, only IGF-I was identified as a significant
independent skeletal predictor. While alterations in DHEAS, IGF-I, and specific cytokines may contribute to skeletal deficits
in patients with CF, of these factors a low IGF-I concentration appears to be most strongly correlated with BMD.
Conclusions These findings may have therapeutic implications for enhancing bone density in these patients. 相似文献
6.
Clinical experience with immediate breast reconstruction using tissue expansion or transverse rectus abdominis musculocutaneous flaps 总被引:5,自引:0,他引:5
We retrospectively reviewed our experience with immediate breast reconstruction in 103 consecutive patients with stage 0 or I breast carcinoma between May 1983 and April 1988. Two reconstructive techniques were used, that is, either tissue expansion with secondary prosthesis implantation (60%) or transverse rectus abdominis musculocutaneous (TRAM) flap (40%). Chemotherapy was administered in 22% of patients without delay or compromise. The mean length of follow-up is 30 months. The complication rate was equal for both groups (24%) with infection being most common in the group of patients with tissue expansion and partial flap necrosis being most common in the group of patients with TRAM flaps. Aesthetic results were superior with use of the TRAM flap. Our experience concurs with previous reports that documented satisfactory results with immediate breast reconstruction without compromising further therapy. We conclude that although the tissue expansion technique yields acceptable results, the TRAM flap yields superior aesthetic results in terms of both appearance and consistency. 相似文献
7.
8.
Scott A Fields Elizabeth Morrison Ernie Yoder Kevin Krane Thomas Agresta Rich Esham Frederick McCurdy Jonathan Rosen James Shumway 《Academic medicine》2002,77(6):543-546
PURPOSE: Chart notes are used to support billing codes under the evaluation and management guidelines of the Health Care Financing Administration (HCFA), in addition to serving as a record of the visit. To better understand the effect of the HCFA documentation guidelines, the authors collected data on how the guidelines affect participation by university- and community-based faculty in clinical education programs. METHOD: In 2000, the authors sent six copies of their questionnaire to the associate deans of the 125 U.S. medical schools and requested they distribute them to all core clerkship directors. The questionnaire consisted of multiple-choice and short-answer questions regarding documentation of medical visits, participation of community-based faculty, understanding of HCFA documentation guidelines, and effects on education programs. RESULTS: The response rate was about 50%. Most of the 379 clerkship directors who responded (77%) stated they were aware the HCFA documentation guidelines include specifications regarding the role medical students can play and documentation of medical visits, and 64% indicated they were concerned the guidelines would affect their educational programs. Concerns included the loss of student independence and active participation in the patient care environment (37), time constraints and the changing balance between education and service (16), loss of faculty and decreased morale (11), and decreased quality of care for patients (7). CONCLUSION: Leaders of medical education must work to modify these guidelines to protect the quality of patients' care, while maximizing students' educational opportunity and participation. 相似文献
9.
Sodium MRI of the human kidney at 3 Tesla. 总被引:6,自引:0,他引:6
Nimrod Maril Yael Rosen Glenn H Reynolds Alex Ivanishev Long Ngo Robert E Lenkinski 《Magnetic resonance in medicine》2006,56(6):1229-1234
The sodium concentration gradient in the kidney (from the cortex to the medulla) serves to regulate fluid homeostasis and is tightly coupled to renal function. It was previously shown that renal function and pathophysiology can be characterized in rat kidneys by measuring the sodium gradient with (23)Na MRI. This study demonstrates for the first time the ability of (23)Na MRI to map the distribution of sodium in the human kidney and to quantify the corticomedullary sodium gradient. The study was performed on a 3T Signa LX scanner (GE) using an in-house-built quadrature surface coil. (23)Na images of volunteers were acquired using a 3D coronal gradient-echo sequence at a spatial resolution of 0.3 x 0.3 x 1.5 cm(3) in a 25-min scan time. The signal intensity (relative to the noise) increased linearly from the cortex to each of the medullae with a mean slope of 1.6 +/- 0.2 in relative arbitrary units per mm (Rel.u./mm, N = 6) and then decreased, as expected, toward the renal pelvis. Water deprivation (12 hr) induced a significant increase of 25% (P < 0.05) in this gradient. Based on these results, we suggest that sodium MRI can serve as a valuable noninvasive method for functional imaging of the human kidney. 相似文献
10.