全文获取类型
收费全文 | 2310篇 |
免费 | 149篇 |
国内免费 | 1篇 |
专业分类
耳鼻咽喉 | 21篇 |
儿科学 | 80篇 |
妇产科学 | 58篇 |
基础医学 | 295篇 |
口腔科学 | 33篇 |
临床医学 | 298篇 |
内科学 | 509篇 |
皮肤病学 | 14篇 |
神经病学 | 198篇 |
特种医学 | 88篇 |
外科学 | 260篇 |
综合类 | 75篇 |
一般理论 | 1篇 |
预防医学 | 262篇 |
眼科学 | 23篇 |
药学 | 113篇 |
中国医学 | 1篇 |
肿瘤学 | 131篇 |
出版年
2023年 | 14篇 |
2022年 | 20篇 |
2021年 | 46篇 |
2020年 | 18篇 |
2019年 | 40篇 |
2018年 | 56篇 |
2017年 | 41篇 |
2016年 | 36篇 |
2015年 | 50篇 |
2014年 | 60篇 |
2013年 | 113篇 |
2012年 | 130篇 |
2011年 | 145篇 |
2010年 | 77篇 |
2009年 | 90篇 |
2008年 | 126篇 |
2007年 | 113篇 |
2006年 | 139篇 |
2005年 | 112篇 |
2004年 | 147篇 |
2003年 | 135篇 |
2002年 | 127篇 |
2001年 | 58篇 |
2000年 | 48篇 |
1999年 | 48篇 |
1998年 | 33篇 |
1997年 | 24篇 |
1996年 | 7篇 |
1995年 | 15篇 |
1994年 | 8篇 |
1993年 | 10篇 |
1992年 | 34篇 |
1991年 | 24篇 |
1990年 | 40篇 |
1989年 | 20篇 |
1988年 | 23篇 |
1987年 | 19篇 |
1986年 | 25篇 |
1985年 | 19篇 |
1984年 | 11篇 |
1983年 | 15篇 |
1982年 | 10篇 |
1981年 | 8篇 |
1979年 | 18篇 |
1978年 | 9篇 |
1976年 | 8篇 |
1975年 | 9篇 |
1973年 | 7篇 |
1972年 | 12篇 |
1971年 | 11篇 |
排序方式: 共有2460条查询结果,搜索用时 31 毫秒
1.
2.
Various forms of signal processing are used in modern ASP hearing aids. The present study investigated the relationship between sentence recognition ability and two types of signal processing used in commercially available hearing aids. Results indicated a significant improvement in sentence recognition ability employing an instrument with adaptive compression (variable release time) versus an instrument with an adaptive high-pass filter with short attack and release times. Data were obtained for a single-talker competing message at several message-to-competition ratios. The adaptive compression system may prove to be beneficial to hearing-impaired listeners in certain background noise environments. 相似文献
3.
Margaret J Bowers Nick J Orr Si Dempsey H Denis Alexander 《Blood coagulation & fibrinolysis》2006,17(5):409-411
We present a case of Bernard Soulier syndrome in a 9-year-old boy caused by a novel genetic mutation. This child was shown to be homozygous for a single nucleotide deletion (c.1077delG) in the GP1BA gene not previously reported. Clinically, the boy has become refractory to platelet transfusions with both allo-antibodies and iso-antibodies and a massive transfusion requirement for ongoing haemorrhage. We describe the critical role that the blood product transfusion continues to play in the management of Bernard Soulier syndrome and discuss therapeutic options in these patients. 相似文献
4.
JoAnn D'Avirro Teresa Dotson Barbara LaPierre Wendy Marshall MaryBeth Mishler Jennifer L. Tanger 《Rehabilitation nursing》1996,21(3):132-138
Restructuring in health care does not have to compromise the pursuit of clinical excellence and quality patient care. The clinical advancement program (CAP) at the Hospital for Special Care is a newly developed multidisciplinary reward and recognition program for clinical staff. The program is integrated into the hospital's structure of service line management and, unlike traditional advancement programs, is open to all levels of care providers: professional personnel, technical staff, and aides. This article describes the basic features of the CAP model and how it was developed by a multidisciplinary task force. 相似文献
5.
Altered gastric emptying in the head-injured patient: relationship to feeding intolerance 总被引:12,自引:0,他引:12
L Ott B Young R Phillips C McClain L Adams R Dempsey P Tibbs U Y Ryo 《Journal of neurosurgery》1991,74(5):738-742
Most patients with moderate to severe head injury initially do not tolerate enteral feedings postinjury. This intolerance is more prolonged than that found in patients suffering other types of trauma. The authors prospectively evaluated 12 patients with moderate to severe head injury (Glasgow Coma Scale score between 4 and 10) throughout their hospitalization for liquid gastric emptying as a possible mechanism for intolerance to enteral feeding. During Week 1, the majority of patients displayed a delay in gastric emptying. Patients also displayed an abnormal biphasic response (gastric emptying faster than normal during the early stage but prolonged later). By Week 2, many patients still had delayed and abnormal biphasic responses to gastric emptying. By Week 3, an improvement was observed with the majority of patients exhibiting rapid gastric emptying, but delays and abnormal biphasic responses were still seen. Patients who initially had rapid or normal gastric emptying tolerated full-strength full-rate feedings significantly earlier compared with those who experienced delayed gastric emptying (8.5 +/- 0.5 days vs. 13.7 +/- 3.2 days, p less than 0.001). All patients tolerated full-strength full-rate feedings by Day 16 postinjury (range 7 to 16 days) except the two patients who displayed delayed gastric emptying for prolonged periods of time (mean 25 days). This is the first study to longitudinally evaluate gastric emptying following head injury. The authors suggest that patients with moderate to severe head injury often experience alterations in gastric emptying which may affect their ability to tolerate enteral feedings. 相似文献
6.
Using abdominal ultrasonographic data and laboratory tests, radiologists often find differential diagnoses of hepatic masses difficult. A computerized second opinion would be especially helpful for clinicians in diagnosing liver cancer because of the difficulty of such diagnoses. A back-propagation neural network was designed to diagnose five classifications of hepatic masses: hepatoma, metastic carcinoma, abscess, cavernous hemangioma, and cirrhosis. The network input consisted of 35 numbers per patient case that represented ultrasonographic data and laboratory tests. The network architecture had 35 elements in the input layer, two hidden layers of 35 elements each, and 5 elements in the output layer. After being trained to a learning tolerance of 1%, the network classified hepatic masses correctly in 48 of 64 cases. An accuracy of 75% is higher than the 50% scored by the average radiology resident in training but lower than the 90% scored by the typical board-certified radiologist. When sufficiently sophisticated, a neural network may significantly improve the analysis of hepatic-mass radiographs. 相似文献
7.
JoAnn G. Congdon Ph.D. R.N. Joan K. Magilvy Ph.D. R.N. FAAN 《Public health nursing (Boston, Mass.)》1995,12(1):18-24
Abstract Rural community and public health nursing are characterized by an impressive commitment of nurses to their communities and a connectedness of people to one another. Home care as an integral part of long-term and acute care for the older adult population has emerged as a vital practice area in community health nursing. The purpose of this ethnographic field study was to describe rural home care for frail older adults from the perspective of those providing and receiving care. More than 250 interviews were conducted with home care providers, recipients and their families, and other community members. The setting included eight culturally and geographically diverse counties in rural Colorado. One major theme is presented: the perceived change in the spirit of rural community nursing due to the overwhelming documentation required for home care reimbursement. Oppressive paperwork requirements impeded practice and resulted in fewer home visits per day, low job satisfaction, increased nursing staff turnover, decreased quality of care, and changed the spirit of community nursing from an emphasis on caring and community service to a focus on reimbursement. The study results have timely implications for health policy formulation as the United States undergoes major health care reform. 相似文献
8.
Low DA Markman J Dempsey JF Mutic S Oldham M Venkatesan R Haacke EM Purdy JA 《Medical physics》2000,27(8):1814-1817
With the development of conformal radiotherapy, particularly intensity modulated radiation therapy (IMRT), there is a clear need for multidimensional dosimeters. A commercial polymerizing gel, BANG-2 gel (MGS Research, Inc., Guilford, CT), has recently been developed that shows potential as a multi-dimensional dosimeter. This study investigates and characterizes the noise and magnetic resonance (MR) artifacts from imaging BANG-2 gels. Seven cylindrical vials (4 cm diam, 20 cm length) were irradiated end on in a water bath and read using MRI (B0=1.5 T, TE=20 ms/100 ms, TR=3000 ms). The gel calibration compared the measured depth-dose distributions in water against the change in solvent-proton R2 relaxivity of the gel. A larger vial (13 cm diam, 14 cm length) was also irradiated to test the calibration accuracy in a vial of sufficient volume for dose distribution measurements. The calibration curve proved accurate to within 1.3% in determining the depth dose measured by the larger vial. An investigation of the voxel-to-voxel (IXIX 3 mm3) noise and sensitivity response curve showed that the voxel-to-voxel variation dominated the dose measurement uncertainty. The voxel-to-voxel standard deviation ranged from 0.2 Gy for the unirradiated gel to 0.7 Gy at 20 Gy. Slice-to-slice R2 magnitude deviations were also observed corresponding to 0.2 Gy. These variations limited the overall accuracy of the gel dose measurements and warrant an investigation of more accurate MR readout sequences. 相似文献
9.
10.
Characterization of the progeny of precursor-T (pre-T) cells maintained in vitro by interleukin-3 (IL-3). Development of T-cell function in vivo. 下载免费PDF全文
We have recently described a bone marrow culture system which is able to maintain a portion of the precursor-T (pre-T) cell compartment of adult murine marrow in vitro, in the presence of interleukin-3 (IL-3), for at least 2 weeks. However, because growth in IL-3 might also induce the differentiation of the pre-T cells, it is necessary to determine the extent to which the developmental potential of the pre-T cells is altered during their residency in vitro. Previously, we analysed the progeny of cultured pre-T cells and compared their intrathymic development, their appearance in the periphery, and their V beta gene utilization to that of the progeny of fresh pre-T cells. Within these parameters, the cells derived from cultured marrow cells did not differ significantly from cells derived from fresh marrow cells. However, these studies did not allow us to determine the functional status of the T-cell progeny of cultured marrow. In the work presented here, we analysed the functional potential of T cells which were derived either from fresh pre-T cells or pre-T cells which had been maintained for 1 week in vitro. The T-cell mediated functions analysed included mitogen- and alloantigen-induced proliferation, IL-2 production, and generation of cytotoxic T cells. We found that the cultured pre-T cells were capable of giving rise to mature, immunocompetent T cells which did not differ significantly from the progeny of fresh pre-T cells in their functional potential. 相似文献