全文获取类型
收费全文 | 2556篇 |
免费 | 195篇 |
国内免费 | 7篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 68篇 |
妇产科学 | 63篇 |
基础医学 | 276篇 |
口腔科学 | 81篇 |
临床医学 | 335篇 |
内科学 | 516篇 |
皮肤病学 | 14篇 |
神经病学 | 109篇 |
特种医学 | 296篇 |
外科学 | 296篇 |
综合类 | 70篇 |
一般理论 | 2篇 |
预防医学 | 269篇 |
眼科学 | 38篇 |
药学 | 173篇 |
中国医学 | 1篇 |
肿瘤学 | 143篇 |
出版年
2022年 | 13篇 |
2021年 | 30篇 |
2020年 | 24篇 |
2019年 | 32篇 |
2018年 | 55篇 |
2017年 | 37篇 |
2016年 | 35篇 |
2015年 | 50篇 |
2014年 | 58篇 |
2013年 | 79篇 |
2012年 | 85篇 |
2011年 | 97篇 |
2010年 | 75篇 |
2009年 | 63篇 |
2008年 | 89篇 |
2007年 | 80篇 |
2006年 | 79篇 |
2005年 | 73篇 |
2004年 | 64篇 |
2003年 | 50篇 |
2002年 | 60篇 |
2001年 | 56篇 |
2000年 | 58篇 |
1999年 | 47篇 |
1998年 | 63篇 |
1997年 | 66篇 |
1996年 | 76篇 |
1995年 | 55篇 |
1994年 | 59篇 |
1993年 | 45篇 |
1992年 | 55篇 |
1991年 | 57篇 |
1990年 | 72篇 |
1989年 | 67篇 |
1988年 | 71篇 |
1987年 | 43篇 |
1986年 | 67篇 |
1985年 | 67篇 |
1984年 | 46篇 |
1983年 | 46篇 |
1982年 | 40篇 |
1981年 | 24篇 |
1980年 | 22篇 |
1979年 | 35篇 |
1978年 | 27篇 |
1977年 | 19篇 |
1976年 | 39篇 |
1975年 | 18篇 |
1970年 | 14篇 |
1969年 | 18篇 |
排序方式: 共有2758条查询结果,搜索用时 15 毫秒
1.
Anuj Shrestha Zeeshan Jawa Kathryn L. Koch Amy B. Rankin Qun Xiang Anand Padmanabhan Matthew S. Karafin Joshua J. Field 《Journal of clinical apheresis》2015,30(6):353-358
Red cell exchange (RCE) is a common procedure in adults with sickle cell disease (SCD). Implantable dual lumen Vortex (DLV) ports can be used for RCE in patients with poor peripheral venous access. We performed a retrospective cohort study of RCE procedures performed in adults with SCD. The main objective of the study was to compare the inlet speed, duration of procedures and rate of complications performed through DLV ports to those performed through temporary central venous and peripheral catheters. Twenty‐nine adults with SCD underwent a total of 318 RCE procedures. Twenty adults had DLV ports placed and 218 procedures were performed using DLV ports. Mean length of follow‐up after DLV port placement was 397 ± 263 days. Six DLV ports were removed due to infection and 1 for malfunction after a mean of 171 ± 120 days. Compared to temporary central venous and peripheral catheters, DLV port procedures had a greater rate of procedural complications, a longer duration, and a lower inlet speed (all P < 0.01). When accounting for the maximum allowable inlet speed to avoid citrate toxicity, 40% of DLV port procedures were greater than 10% below maximum speed, compared to 7 and 14% of procedures performed through temporary central venous and peripheral catheters (P < 0.0001). In conclusion, DLV ports can be used for RCE in adults with SCD, albeit with more procedural complications and longer duration. The smaller internal diameter and longer catheter of DLV ports compared to temporary central venous catheters likely accounts for the differences noted. J. Clin. Apheresis 30:353–358, 2015. © 2015 Wiley Periodicals, Inc. 相似文献
2.
3.
4.
5.
Intracranial circulation: pulse-sequence considerations in three- dimensional (volume) MR angiography 总被引:2,自引:0,他引:2
The technique and feasibility of magnetic resonance (MR) angiography of intracranial vessels were studied in 35 healthy volunteers. Variations in image orientation, repetition time (TR), and flip angle were evaluated to determine their effects on flow-related enhancement. Gradient modifications--including echo time (TE), motion compensation, bandwidth, and field of view--were also studied in an effort to reduce motion-induced phase shifts. Results indicated that a FISP (fast imaging with steady precession) sequence with a TR of 50 msec, TE of 15 msec, velocity compensation in the read and section-select directions, acceleration compensation in the read direction, anisotropic volume, and a 1.25-mm partition thickness produced three-dimensional angiographic MR images that were accurate and reproducible in the depiction of the major intracranial vessels. Difficulties with field of view, persistent signal void secondary to higher-order motion, and spatial resolution remain major problems requiring additional study. 相似文献
6.
While the family's primacy in the patient's adaptation to chronic illness increasingly is being recognized by health professionals and social scientists, the reverse side of the coin, that is, the impact of chronicity on the family, has received little attention. A life-span development perspective is used to enrich the more traditional frameworks employed to study family development and also as a unifying framework from which to view the impact of illness on individual family members and the family as a unit. A review of selected literature reveals a profile of families most at risk for serious disruption in situations involving chronic illness. Propositions suggesting interventions directed at patients and families experiencing chronicity are derived. 相似文献
7.
8.
9.
Background
Glioblastoma multiforme is the most malignant form of brain tumor. Despite treatment including surgical resection, adjuvant chemotherapy, and radiation, these tumors typically recur. The recurrent tumor is often resistant to further therapy with the same agent, suggesting that the surviving cells that repopulate the tumor mass have an intrinsic genetic advantage. We previously demonstrated that cells selected for resistance to 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) are near-diploid, with over-representation of part or all of chromosomes 7 and 22. While cells from untreated gliomas often have over-representation of chromosome 7, chromosome 22 is typically under-represented. 相似文献10.