全文获取类型
收费全文 | 9342篇 |
免费 | 637篇 |
国内免费 | 26篇 |
专业分类
耳鼻咽喉 | 73篇 |
儿科学 | 413篇 |
妇产科学 | 213篇 |
基础医学 | 1215篇 |
口腔科学 | 242篇 |
临床医学 | 925篇 |
内科学 | 2056篇 |
皮肤病学 | 128篇 |
神经病学 | 826篇 |
特种医学 | 190篇 |
外科学 | 1154篇 |
综合类 | 161篇 |
一般理论 | 6篇 |
预防医学 | 993篇 |
眼科学 | 163篇 |
药学 | 659篇 |
2篇 | |
中国医学 | 39篇 |
肿瘤学 | 547篇 |
出版年
2023年 | 110篇 |
2022年 | 173篇 |
2021年 | 362篇 |
2020年 | 222篇 |
2019年 | 291篇 |
2018年 | 316篇 |
2017年 | 230篇 |
2016年 | 198篇 |
2015年 | 221篇 |
2014年 | 320篇 |
2013年 | 441篇 |
2012年 | 647篇 |
2011年 | 637篇 |
2010年 | 373篇 |
2009年 | 324篇 |
2008年 | 508篇 |
2007年 | 542篇 |
2006年 | 475篇 |
2005年 | 411篇 |
2004年 | 429篇 |
2003年 | 391篇 |
2002年 | 337篇 |
2001年 | 142篇 |
2000年 | 142篇 |
1999年 | 133篇 |
1998年 | 78篇 |
1997年 | 61篇 |
1996年 | 48篇 |
1995年 | 44篇 |
1994年 | 51篇 |
1993年 | 43篇 |
1992年 | 80篇 |
1991年 | 82篇 |
1990年 | 76篇 |
1989年 | 70篇 |
1988年 | 67篇 |
1987年 | 79篇 |
1986年 | 57篇 |
1985年 | 58篇 |
1984年 | 45篇 |
1983年 | 71篇 |
1982年 | 39篇 |
1981年 | 30篇 |
1980年 | 32篇 |
1979年 | 36篇 |
1978年 | 32篇 |
1976年 | 35篇 |
1974年 | 35篇 |
1970年 | 35篇 |
1969年 | 31篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
S K Gupta A K Abraham G K Mani K M Cherian J S Moorthy K Bhaskaran 《Japanese heart journal》1987,28(4):507-514
Three cases of chronic rheumatic heart disease with involvement of all four valves are presented. The involvement of tricuspid and pulmonary valves was suspected clinically and was confirmed by two-dimensional echo, Doppler, hemodynamic and angiographic findings. These findings were also verified surgically and histopathologically in 2 cases. One of the cases died after cardiac catheterization; the other 2 cases were treated surgically with success. 相似文献
22.
Teng-Nan Lin BS Albert Y. Sun PhD Grace Y. Sun PhD 《Alcoholism, clinical and experimental research》1988,12(6):795-800
In the presence of ATP, MgCl2, and CoASH, somal plasma membranes isolated from rat cerebral cortex were active in transferring arachidonic acid to phosphatidylinositols, phosphatidylcholines, and triacylglycerols. Ethanol (350-525 mM) added to the incubation mixture inhibited arachidonic acid incorporation into phospholipids, while it enhanced the incorporation into triacylglycerols. Under these conditions, ethanol was found to react with arachidonic acid to form arachidonoyl ethyl ester. The incorporation of labeled arachidonic acid into glycerolipids as well as the synthesis of ethyl esters required the presence of ATP and CoASH for maximal activity. Nevertheless, each uptake process exhibited a unique pH profile. The esterification of arachidonic acid was not specific for ethanol as other aliphatic alcohols (e.g., propanol and butanol) were also able to react with labeled arachidonic acid to form the respective esters. Somal plasma membranes isolated from mice after chronic ethanol administration showed an increase in arachidonoyl transfer to both phospholipids and triacylglycerols. When these membranes were challenged with ethanol (325 mM), those isolated from the chronic ethanol group showed a greater increase in the labeling of triacylglycerols and ethyl esters than those from controls. Thus, different acyltransferases exhibite different responses to the effects of ethanol in vitro and in vivo. 相似文献
23.
Actinobacillus actinomycetemcomitans, a fastidious gram-negative bacillus, has been reported as the cause of prosthetic valve endocarditis in 11 patients. Two additional patients are reported and the literature is reviewed. All cases occurred greater than 1 year after implantation of the prosthesis. Six of the 13 patients had had recent dental work or had poor dentition. Three patients had received endocarditis prophylaxis. Ten of 13 were cured with antibiotics alone. Only one patient suffered from congestive heart failure, and only one had documented evidence of major systemic emboli during antimicrobial therapy. Valve replacement was necessary in only two during antimicrobial therapy. A actinomycetemcomitans should be considered as a possible etiologic agent in late prosthetic valve endocarditis, particularly when blood cultures are initially negative. A regimen of a beta-lactam antibiotic in combination with an aminoglycoside is recommended for 4-6 weeks. The excellent in vitro activity of the third-generation cephalosporins and rifampin promise new therapeutic options. 相似文献
24.
Patellar instability after total knee arthroplasty 总被引:4,自引:0,他引:4
Twenty-five knees with symptomatic lateral patellar instability after total knee arthroplasty (TKA) were treated by operative realignment. Causes of instability include errors in surgical technique, quadriceps imbalance, and trauma. Fourteen knees had proximal realignment, nine had combined proximal and distal realignment, and two had component revision. At an average follow-up period of 50 months, 20 knees had normal patellar tracking and five had recurrent instability. Two patellar tendon ruptures occurred after combined realignment. Proximal realignment alone, in the absence of component malposition, is recommended for the management of patellar instability. Component malposition should be corrected by component revision. Combined proximal and distal realignment procedures are recommended only with great caution because of the predisposition to serious complications such as patellar tendon rupture. 相似文献
25.
26.
M Grace 《British dental journal》1992,173(8):282-285
The problem with improving quality in dental practice is not so much a difficulty with understanding exactly what quality means, but more a lack of clear guidance as to how to take the simple, practical steps to achieving that improvement in the daily pressures of practice life. This article describes Quality Development, a simple and practical method that can be used in general practice to help the dental team achieve the objectives in quality care that are appropriate to them. 相似文献
27.
Extensive intraductal component (EIC) has been reported to have a prominent role in local recurrence after treatment of early-stage breast cancer with lumpectomy and irradiation. Pathologic specimens from 250 breasts (245 patients) treated between June 1982 and June 1990 with lumpectomy, immediate (boost) interstitial iridium-192 to 15-20 Gy, and external-beam irradiation to the entire breast to 45-50 Gy were reviewed. EIC was present in 61 breasts. At a median follow-up period of 58 months (range, 14-110 months), there were 10 recurrences in the 250 treated breasts. Of these 10, three were in patients from the group with EIC. The 10-year actuarial recurrence rates in breasts with and without EIC were 9.1% and 5.2%, respectively. The difference between the two rates was not significant. If an immediate boost with interstitial iridium is used in therapy, the influence of EIC on local failure is insignificant. 相似文献
28.
Nimodipine treatment in poor-grade aneurysm patients. Results of a multicenter double-blind placebo-controlled trial 总被引:4,自引:0,他引:4
K C Petruk M West G Mohr B K Weir B G Benoit F Gentili L B Disney M I Khan M Grace R O Holness 《Journal of neurosurgery》1988,68(4):505-517
A multicenter, randomized placebo-controlled double-blind trial of nimodipine in poor-grade aneurysm patients was carried out in 17 Canadian hospitals. Of 188 patients enrolled in the trial, 32 were excluded for protocol violations and two were excluded due to statistical considerations, leaving 154 patients for valid outcome analysis. Nimodipine treatment was associated with a significantly better outcome (p less than 0.001): 21 (29.2%) of 72 nimodipine-treated patients had a good outcome at 3 months after subarachnoid hemorrhage (SAH) compared to eight (9.8%) of 82 placebo-treated patients. Delayed ischemic deficits from vasospasm alone were significantly less frequent in the nimodipine group (p less than 0.05) with permanent deficits occurring in five nimodipine-treated patients (6.9%) and in 22 placebo-treated patients (26.8%). Improvement in the good outcome rate and reduction in delayed ischemic deficits from vasospasm alone occurred in both Grade 3 and 4 patients, with no difference between nimodipine- and placebo-treated patients being found in Grade 5 patients. Repeat angiography after Day 4 was carried out in 124 patients. There was no significant difference in the incidence of moderate or severe diffuse spasm, which was seen in 64.3% of nimodipine-treated patients and 66.2% of placebo-treated patients. The authors conclude that nimodipine treatment in poor-grade patients with SAH results in an increase in the number of good outcomes and a reduction in the incidence of delayed neurological deterioration due to vasospasm. This effect occurs by a mechanism other than prevention of large-vessel spasm as visualized on angiography. 相似文献
29.
This investigation used a derivation of acoustic reflection (AR) technology to make cross-sectional measurements of changes due to aging in the oral and pharyngeal lumina of male and female speakers. The purpose of the study was to establish preliminary normative data for such changes and to obtain acoustic measurements of changes due to aging in the formant frequencies of selected spoken vowels and their long-term average spectra (LTAS) analysis. Thirty-eight young men and women and 38 elderly men and women were involved in the study. The oral and pharyngeal lumina of the participants were measured with AR technology, and their formant frequencies were analyzed using the Kay Elemetrics Computerized Speech Lab. The findings have delineated specific and similar patterns of aging changes in human vocal tract configurations in speakers of both genders. Namely, the oral cavity length and volume of elderly speakers increased significantly compared to their young cohorts. The total vocal tract volume of elderly speakers also showed a significant increment, whereas the total vocal tract length of elderly speakers did not differ significantly from their young cohorts. Elderly speakers of both genders also showed similar patterns of acoustic changes of speech production, that is, consistent lowering of formant frequencies (especially F1) across selected vowel productions. Although new research models are still needed to succinctly account for the speech acoustic changes of the elderly, especially for their specific patterns of human vocal tract dimensional changes, this study has innovatively applied the noninvasive and cost-effective AR technology to monitor age-related human oral and pharyngeal lumina changes that have direct consequences for speech production. 相似文献
30.