全文获取类型
收费全文 | 988篇 |
免费 | 74篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 12篇 |
儿科学 | 42篇 |
妇产科学 | 31篇 |
基础医学 | 95篇 |
口腔科学 | 31篇 |
临床医学 | 106篇 |
内科学 | 203篇 |
皮肤病学 | 12篇 |
神经病学 | 39篇 |
特种医学 | 24篇 |
外科学 | 158篇 |
综合类 | 73篇 |
一般理论 | 1篇 |
预防医学 | 97篇 |
眼科学 | 3篇 |
药学 | 81篇 |
中国医学 | 3篇 |
肿瘤学 | 53篇 |
出版年
2024年 | 2篇 |
2023年 | 20篇 |
2022年 | 49篇 |
2021年 | 57篇 |
2020年 | 36篇 |
2019年 | 56篇 |
2018年 | 43篇 |
2017年 | 33篇 |
2016年 | 35篇 |
2015年 | 33篇 |
2014年 | 30篇 |
2013年 | 36篇 |
2012年 | 78篇 |
2011年 | 67篇 |
2010年 | 39篇 |
2009年 | 34篇 |
2008年 | 52篇 |
2007年 | 50篇 |
2006年 | 36篇 |
2005年 | 38篇 |
2004年 | 47篇 |
2003年 | 40篇 |
2002年 | 27篇 |
2001年 | 22篇 |
2000年 | 20篇 |
1999年 | 11篇 |
1998年 | 8篇 |
1997年 | 7篇 |
1996年 | 6篇 |
1995年 | 5篇 |
1994年 | 4篇 |
1993年 | 6篇 |
1992年 | 7篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1971年 | 1篇 |
排序方式: 共有1064条查询结果,搜索用时 24 毫秒
11.
Muhammad Amjad Awan Javeria Arshad Bushra Allah Rakha Muhammad Sajjad Ansari Muhammad Waseem Ali Fouladi-Nashta David Miller Shamim Akhter 《Andrologia》2021,53(3):e13991
This study reports the first evaluation of sperm hyaluronan binding assay (HBA) for predicting the fertility of Nili-Ravi buffalo bulls in relation to standard parameters of sperm quality. Cryopreserved semen doses of low (n = 6), medium (n = 3) and high fertility (n = 8) bulls based on their respective return rates were used. Significantly, more spermatozoa bound to hyaluronan from the most fertile bulls (57.15% ± 1.44) compared with medium (42.46% ± 1.08) and low fertility bulls (29.70% ± 0.78). A strongly positive correlation (r = .824, p < .01) was found between HBA and fertility that predicts a 67.9% variability (r2 = .679, p < .01) in fertility. HBA was also strongly positively correlated with sperm viability (r = .679, p < .01) followed by their live/dead ratio (r = .637, p < .01), uncapacitated spermatozoa (r = .631, p < .01), normal apical ridge (r = .459, p < .01), motility (r = .434, p < .01), mature spermatozoa with low residual histones (r = .364, p < .01), high plasma membrane integrity (r = .316, p < .01) and nonfragmented DNA levels (r = .236, p < .05). It was negatively correlated with spermatozoa having reacted acrosome (r = −.654, p < .01). A fertility model built using a combination of sperm HBA and either sperm livability or viability predicts, respectively, 86.1% (r2 = .861, p < .01) and 85.9% (r2 = .859, p < .01) variability in buffalo bull fertility. In conclusion, sperm HBA may prove to be a single robust predictor of Nili-Ravi buffalo bull fertility. 相似文献
12.
Akhter MP Iwaniec UT Covey MA Cullen DM Kimmel DB Recker RR 《Calcified tissue international》2000,67(4):337-344
The purpose of this study was to assess breed-related differences in bone histomorphometry, bone biomechanics, and serum
biochemistry in three mouse breeds shown to differ in bone mineral density (BMD) (as measured by DXA) and bone mineral content
(BMC). Femurs, tibiae, and sera were collected from 16-week-old C3H/HeJ {C3H}, C57BL/6J {BL6}, and DBA/2J {DBA}mice (n = 12/breed).
Data collected included BMC and BMD (femora), histomorphometry of cancellous (distal femur) and cortical bone (diaphyseal
tibiae and femora), bone strength (femora), and serum alkaline phosphatase (ALP). Consistent with previous reports, BMC and
BMD were higher in C3H than in BL6 or DBA mice. The higher BMD in the C3H breed was associated with greater cancellous bone
volume, cortical bone area, periosteal bone formation rate, biomechanical strength, and serum ALP. However, mid-diaphyseal
total femoral and tibial cross-sectional area and moment of inertia were greatest in BL6, intermediate in C3H, and lowest
in DBA mice. The specific distribution of cortical bone in C3H, BL6, DBA mice represents a difference in adaptive response
to similar mechanical loads in these breeds. This difference in adaptive response may be intrinsic to the adaptive mechanism,
or may be intrinsic to the bone tissue material properties. In either case, the bone-adaptive response to ordinary mechanical
loads in the BL6 mice yields bones of lower mechanical efficiency (less stiffness per unit mass of bone tissue) and does not
adapt as well as that of the C3H mice where the final product is a bone with greater resistance to bending under load. We
suggest that the size, shape, and BMD of the bone are a result of breed-specific genetically regulated cellular mechanisms.
Compared with the C3H mice, the lower BMD in BL6 mice is associated with long bones that are weaker because the larger cross-sectional
area fails to compensate completely for their lower BMD and BMC.
Received: 16 November 1999 / Accepted: 19 April 2000 / Online publication: 27 July 2000 相似文献
13.
Iwaniec UT Fung YK Cullen DM Akhter MP Haven MC Schmid M 《Calcified tissue international》2000,67(1):68-74
Limited research in young adults and immature animals suggests a detrimental effect of tobacco on bone during growth. This
study investigated the effects of nicotine, the major alkaloid component of tobacco, on calciotropic hormone concentrations
and bone status in growing female rats. One-month-old animals received either saline (n = 10), nicotine at 3.0 mg/kg/day (n
= 10), or nicotine at 4.5 mg/kg/day (n = 10) administered subcutaneously via osmotic minipumps for either 2 or 3 months. Sera,
femora, tibiae, and lumbar vertebrae (3–5) were collected at necropsy. The concentrations of serum calcium, phosphorus, 25-hydroxyvitamin
D, 1,25-dihydroxyvitamin D, parathyroid hormone, calcitonin, and insulin-like growth factor-I were determined. Bone variables
evaluated included mineral content and density (vertebrae and femora), cancellous and cortical histomorphometry (tibiae),
and bone strength (vertebrae and femora). Statistically significant differences in serum mineral and hormone concentrations
were not associated with nicotine dose or exposure time. No significant nicotine treatment effects were detected for bone
mineral content and density, bone histomorphometry, or bone strength. We conclude that nicotine treatment for 2 or 3 months
at serum concentrations in the upper range of those found in smokers has no detrimental effect on bone mass, volume, or strength
in the growing rat.
Received: 20 May 1999 / Accepted: 21 January 2000 相似文献
14.
15.
This urban community clinic had poor asthma outcomes compared to the state of Minnesota. The standard of care supports an annual Asthma Action Plan (AAP). However, the majority of patients at this clinic had not received one. This quality improvement project aimed to improve asthma control, measured by an asthma control test of at least 20, through AAP implementation supported by all team members. The clinic’s interdisciplinary champion group implemented workflow changes via practice facilitation and Plan-Do-Study-Act cycles. Asthma control rates increased from 23% to 58% in adults and 45% to 63% in children over one year, a statistically significant change. 相似文献
16.
17.
Kohel Kara Hatton-Bowers Holly Williams Natalie Dev Dipti Behrends Donnia Hulse Emily Rida Zainab Dingman Holly Dinkel Danae Gebhart Liz 《Maternal and child health journal》2021,25(4):510-520
Maternal and Child Health Journal - Breastfeeding and responsive feeding are important practices that support the health of infants and women. In the United States, breastfeeding continuation rates... 相似文献
18.
Mubin I. Syed Talal Akhter Uzma Wahid Azim Shaikh Mohsin Mirza Granville J. Tengesdahl 《Cardiovascular Revascularization Medicine》2012,13(2):141.e7-141.e11
Subclavian stenting can be extremely difficult in a hostile type II aortic arch (with acute angulation of the subclavian artery origin) or type III aortic arch. This case illustrates use of a low-profile system to gain through-and-through (flossing) access through the brachial artery to facilitate stenting via the femoral approach. This approach can be useful in patients with small brachial arteries where the risk of complication may be high if a standard vascular sheath was placed for stenting via the brachial approach. This technique also avoids the use of a surgical cut down. 相似文献
19.
20.
The additional utility of two‐dimensional strain in detection of coronary artery disease presence and localization in patients undergoing dobutamine stress echocardiogram
下载免费PDF全文
![点击此处可从《Echocardiography (Mount Kisco, N.Y.)》网站下载免费的PDF全文](/ch/ext_images/free.gif)