全文获取类型
收费全文 | 7867篇 |
免费 | 728篇 |
国内免费 | 83篇 |
专业分类
耳鼻咽喉 | 55篇 |
儿科学 | 337篇 |
妇产科学 | 122篇 |
基础医学 | 1031篇 |
口腔科学 | 272篇 |
临床医学 | 945篇 |
内科学 | 1422篇 |
皮肤病学 | 281篇 |
神经病学 | 857篇 |
特种医学 | 703篇 |
外科学 | 1034篇 |
综合类 | 145篇 |
一般理论 | 4篇 |
预防医学 | 644篇 |
眼科学 | 63篇 |
药学 | 423篇 |
2篇 | |
中国医学 | 2篇 |
肿瘤学 | 336篇 |
出版年
2021年 | 79篇 |
2020年 | 70篇 |
2019年 | 86篇 |
2018年 | 126篇 |
2017年 | 95篇 |
2016年 | 100篇 |
2015年 | 128篇 |
2014年 | 178篇 |
2013年 | 251篇 |
2012年 | 276篇 |
2011年 | 293篇 |
2010年 | 236篇 |
2009年 | 241篇 |
2008年 | 292篇 |
2007年 | 310篇 |
2006年 | 310篇 |
2005年 | 305篇 |
2004年 | 290篇 |
2003年 | 264篇 |
2002年 | 264篇 |
2001年 | 283篇 |
2000年 | 268篇 |
1999年 | 235篇 |
1998年 | 210篇 |
1997年 | 213篇 |
1996年 | 208篇 |
1995年 | 179篇 |
1994年 | 189篇 |
1993年 | 158篇 |
1992年 | 171篇 |
1991年 | 184篇 |
1990年 | 173篇 |
1989年 | 182篇 |
1988年 | 157篇 |
1987年 | 154篇 |
1986年 | 132篇 |
1985年 | 131篇 |
1984年 | 105篇 |
1982年 | 71篇 |
1981年 | 65篇 |
1980年 | 67篇 |
1979年 | 62篇 |
1978年 | 60篇 |
1977年 | 69篇 |
1976年 | 80篇 |
1975年 | 81篇 |
1974年 | 59篇 |
1973年 | 57篇 |
1972年 | 59篇 |
1971年 | 48篇 |
排序方式: 共有8678条查询结果,搜索用时 0 毫秒
21.
22.
23.
A fatal case of penicillin resistant Staphylococcus lugdunensis endocarditis on a native valve damaged by rheumatic fever is described. A retrospective examination of 978 tube coagulase negative staphylococcal blood culture isolates was also performed to determine how often this species is isolated. None of the 978 isolates was identified as S lugdunensis. It is concluded that ornithine decarboxylase production is the only reliable method of identifying this species. 相似文献
24.
Association of atrophy of the medial temporal lobe with reduced blood flow in the posterior parietotemporal cortex in patients with a clinical and pathological diagnosis of Alzheimer''s disease. 下载免费PDF全文
K A Jobst A D Smith C S Barker A Wear E M King A Smith P A Anslow A J Molyneux B J Shepstone N Soper et al. 《Journal of neurology, neurosurgery, and psychiatry》1992,55(3):190-194
A combination of medial temporal lobe atrophy, shown by computed tomography, and reduced blood flow in the parietotemporal cortex, shown by single photon emission tomography, was found in 86% (44/51) of patients with a clinical diagnosis of senile dementia of the Alzheimer type (SDAT). The same combination of changes was found in four out of 10 patients with other clinical types of dementia and in two out of 18 with no evidence of cognitive deficit. Of the 12 patients who died, 10 fulfilled histopathological criteria for Alzheimer's disease, nine of them having a clinical diagnosis of SDAT, and one a clinical diagnosis of multi-infarct dementia. All 10 patients with histopathologically diagnosed Alzheimer's disease had shown a combination of hippocampal atrophy and reduced parietotemporal blood flow in life. In 10 patients (nine with SDAT) out of 12 in whom the hippocampal atrophy was more noticeable on one side of the brain than on the other the parietotemporal perfusion deficit was also asymmetrical, being greater on the side showing more hippocampal atrophy. These results suggest that the combination of atrophy of the hippocampal formation and reduced blood flow in the parietotemporal region is a feature of dementia of the Alzheimer type and that the functional change in the parietotemporal region might be related to the loss of the projection neurons in the parahippocampal gyrus that innervate this region of the neocortex. 相似文献
25.
Ralls PW; Johnson MB; Kanel G; Dobalian DM; Colletti PM; Boswell WD Jr; Radin DR; Halls JM 《Radiology》1986,161(2):451-454
FM sonography - a signal-processing technique that uses frequency and phase information as well as amplitude data - shows promise in evaluation of patients with diffuse liver disease. In a prospective blinded review of 37 patients with biopsy-proved liver disease and 42 healthy volunteers, FM sonography was clearly superior to traditional amplitude-based (AM) sonography in distinguishing healthy from diseased subjects. Statistically significant differences were seen in accuracy (FM, 98.7%; AM, 84.8%), sensitivity (FM, 97.3%; AM, 70.3%), and negative predictive value (FM, 97.7%; AM, 78.8%). Our data also suggest that current FM sonographic techniques cannot differentiate among histologic findings associated with different hepatic parenchymal abnormalities. It is unclear, therefore, whether FM imaging can reduce the numbers of patients who require biopsy for diagnosis or the frequency of biopsy procedures in patients with known disease. 相似文献
26.
Among the 81 cultures of Salmonella typhimurium of phage type 141 examined, 72 had been isolated from Sheffield incidents in 1984-5 and 9 were Scottish isolates from 1986-7. All of these cultures from diverse sources belonged to primary biotype 31; 79 were of full biotype 31beg and 2 anaerogenic cultures were of full biotype 31begj. This is the first known occasion on which an epidemic strain of S. typhimurium of phage type/biotype 141/31beg has been implicated in outbreaks of human or animal infection in the UK. Because previous epidemic strains of S. typhimurium of phage type 141 in the UK belonged to biotypes 1f and 9f which are phylogenetically unrelated to biotype 31beg, the likely origin of this most recent epidemic S. typhimurium strain of phage type/biotype 141/31beg is discussed. 相似文献
27.
S F Johnson S B Johnson W E Strodel D E Barker P A Kearney 《The Journal of trauma》1991,31(11):1546-1550
Proximal upper extremity (subclavian and axillary) vascular injury (SAVI) and brachial plexus injury (BPI) occur uncommonly. However, BPI may be associated with SAVI and frequently is an important determinant of long-term disability. The medical records of patients with traumatic SAVI, BPI, or both over a 5-year period were reviewed. A total of 31 patients were identified. The group was predominantly male (28 men/3 women) with a mean age of 30.5 +/- 1.8 years (range, 15-63 years). Blunt trauma accounted for 43.5% of SAVI cases and 77.8% of BPI cases. Thirteen patients (41.9%) sustained SAVI alone (group I), 10 patients (32.2%) had combined SAVI and BPI (group II), and 8 patients (25.9%) had BPI alone (group III). Subclavian and axilliary vascular injury occurred in 10 of 18 patients (55.6%) with a BPI. Brachial plexus injury occurred in 10 of 23 patients (43.5%) with a SAVI. Patients with SAVI from blunt trauma were significantly more likely to have an associated complete BPI than patients with penetrating trauma. All patients with a complete BPI (6 patients) had an associated SAVI regardless of mechanism of injury. Only one patient with a partial BPI from blunt trauma had an associated SAVI. The Injury Severity Score was significantly higher for patients in group II. An average of 2.8 and 3.3 associated injuries were observed in patients with SAVI (groups I and II) versus patients without SAVI (group III), respectively. No patient who had a complete BPI showed an improvement in neurologic status during a mean follow-up of 7.2 months. No late vascular sequelae occurred in group-III patients.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
28.
A questionnaire was sent to 101 Nucleus 22-channel cochlear implant recipients aged 65 years and older to investigate the perceived impact of cochlear implantation on their quality of life. The questionnaire was designed to gain insight into the patient's daily use of the Nucleus implant. Sixty-seven questionnaires were returned over a 3-month period. The results of the survey showed that elderly cochlear implant patients obtained similar benefits to younger adult patients who were implanted with the same device. We believe that the results of this study will aid other centers when counseling elderly patients on the expected daily functional benefits of this device. 相似文献
29.
Brian J. Soher Peter C. M. van Zijl Jeffrey H. Duyn Peter B. Barker 《Magnetic resonance in medicine》1996,35(3):356-363
Multislice proton MR spectroscopic images (SI) of the brain were quantitated, using the phantom replacement technique. In 16 normal volunteers, ranging in age from 5 to 74 years, average “whole brain” concentrations of choline (Cho), creatine (Cr), and N-acetylaspartate (NAA) were found to be 2.4 ± 0.4, 7.9 ± 1.3, and 11.8 ± 1.0 (mM, mean ± SD), respectively. These values are in good general agreement with those previously determined by single-voxel localization techniques. Cortical gray matter was found to have lower Cho and NAA levels, compared to those of white matter, corpus callosum, and basal ganglia. Cho was also found to increase significantly with age in several locations. Quantitative multislice proton SI is feasible in the clinical environment, and regional and age-dependent variations occur that must be accounted for when evaluating spectra from pathological conditions. 相似文献
30.
D Macfoy J Hewitt E Barker W A Francis 《European journal of obstetrics, gynecology, and reproductive biology》1992,43(1):35-37
Over a 13-month period in a newly opened assisted conception unit at the Women's Hospital, Liverpool, gamete intra-fallopian transfer using donor semen, GIFT (D) was offered to eighteen couples who had failed to conceive after numerous cycles of treatment with artificial insemination by donor semen (AID). The indication for the use of donor semen was either azo- or severe oligoaesthenospermia, and, in addition, the female partners have been exhaustively investigated with no major cause found to account for the couple's infertility. Using a basic clomiphene citrate and human menopausal gonadotrophin protocol it was possible to achieve a pregnancy rate of 56% per GIFT (D) cycle. As a consequence of these results it is now our policy to treat couples whose infertility is due to an unresolvable male factor with AID for 12 cycles only. If they have been unsuccessful in achieving a pregnancy after this time, they are offered GIFT (D). 相似文献