全文获取类型
收费全文 | 2080篇 |
免费 | 95篇 |
国内免费 | 114篇 |
专业分类
儿科学 | 69篇 |
妇产科学 | 13篇 |
基础医学 | 208篇 |
口腔科学 | 27篇 |
临床医学 | 223篇 |
内科学 | 459篇 |
皮肤病学 | 43篇 |
神经病学 | 64篇 |
特种医学 | 452篇 |
外国民族医学 | 1篇 |
外科学 | 344篇 |
综合类 | 46篇 |
预防医学 | 85篇 |
眼科学 | 27篇 |
药学 | 128篇 |
中国医学 | 3篇 |
肿瘤学 | 97篇 |
出版年
2023年 | 7篇 |
2022年 | 10篇 |
2021年 | 22篇 |
2020年 | 9篇 |
2019年 | 18篇 |
2018年 | 26篇 |
2016年 | 25篇 |
2015年 | 31篇 |
2014年 | 34篇 |
2013年 | 63篇 |
2012年 | 55篇 |
2011年 | 60篇 |
2010年 | 66篇 |
2009年 | 63篇 |
2008年 | 67篇 |
2007年 | 106篇 |
2006年 | 70篇 |
2005年 | 92篇 |
2004年 | 50篇 |
2003年 | 59篇 |
2002年 | 46篇 |
2001年 | 47篇 |
2000年 | 45篇 |
1999年 | 45篇 |
1998年 | 101篇 |
1997年 | 99篇 |
1996年 | 108篇 |
1995年 | 70篇 |
1994年 | 66篇 |
1993年 | 67篇 |
1992年 | 23篇 |
1991年 | 46篇 |
1990年 | 39篇 |
1989年 | 60篇 |
1988年 | 44篇 |
1987年 | 59篇 |
1986年 | 40篇 |
1985年 | 53篇 |
1984年 | 26篇 |
1983年 | 21篇 |
1982年 | 29篇 |
1981年 | 24篇 |
1980年 | 39篇 |
1979年 | 17篇 |
1978年 | 20篇 |
1977年 | 20篇 |
1976年 | 30篇 |
1975年 | 18篇 |
1974年 | 6篇 |
1973年 | 9篇 |
排序方式: 共有2289条查询结果,搜索用时 15 毫秒
991.
Riera C Fisa R Ribera E Carrió J Falcó V Gállego M Moner L Molina I Portús M 《The American journal of tropical medicine and hygiene》2005,73(6):1012-1015
The use of culture and a nested polymerase chain reaction (PCR) of blood in predicting the probability of relapse was evaluated in 20 patients co-infected with Leishmania and human immunodeficiency virus (HIV). Fourteen of 20 patients relapsed, with 24 clinical relapses diagnosed. During clinical relapse, the parasite was detected by culture in 21 of 24 blood samples and by nested PCR in 23 of 24 blood samples. After treatment and during asymptomatic periods, the parasite was detected by culture in 18 (19.1%) of 94 blood samples and by nested PCR in 58 (61.7%) of 94 blood samples. For positive blood cultures, the Kaplan-Meier probability estimates for relapse at 6, 12, 18, and 24 months were 44%, 68%, 76%, and 76%, respectively, while for positive nested PCRs, the estimates were 20%, 33%, 45%, and 50%, respectively. For negative blood cultures, relapse probabilities for the same time points were 7%, 12%, 12%, and 12%, while for negative nested PCRs, these probabilities were 8%, 14%, 21%, and 26%. Nested PCR-positive results in asymptomatic periods indicated presence of the parasite, but not necessarily relapse. However, the presence of viable parasites during post-treatment follow-up increased the probability of relapse and showed that culture positivity could be a good relapse marker. 相似文献
992.
993.
Background
There is a considerable body of literature which indicates that contrast thresholds for the detection of sinusoidal grating patterns are abnormally high in glaucoma, though just how these elevations are related to the location of visual field loss remains unknown. Our aim, therefore, has been to determine the relationship between contrast threshold elevation and visual field loss in corresponding regions of the peripheral visual field in glaucoma patients. 相似文献994.
Respiratory tract tumors in hamsters induced by benzo(a)pyrene 总被引:1,自引:0,他引:1
995.
Male rats received 25 Gy (2,500 rad) of gamma rays to the right hemithorax and were killed three or six months later. Microscopic pulmonary abnormalities developed sooner and progressed more rapidly in animals given control feed than in those given the collagen antagonist D-penicillamine (10 mg/day, p.o.). Three and four months after irradiation, hypoperfusion and radiographic hyperlucency of the right lung were observed in both the treated and control animals. 相似文献
996.
Three dimensional imaging of the myocardium with radionuclides 总被引:1,自引:0,他引:1
997.
Al-Maiyah M Bajwa A Mackenney P Port A Gregg PJ Hill D Finn P 《The Journal of bone and joint surgery. British volume》2005,87(4):556-559
We conducted a randomised, controlled trial to determine whether changing gloves at specified intervals can reduce the incidence of glove perforation and contamination in total hip arthroplasty. A total of 50 patients were included in the study. In the study group (25 patients), gloves were changed at 20-minute intervals or prior to cementation. In the control group (25 patients), gloves were changed prior to cementation. In addition, gloves were changed in both groups whenever there was a visible puncture. Only outer gloves were investigated.Contamination was tested by impression of gloved fingers on blood agar and culture plates were subsequently incubated at 37 degrees C for 48 hours. The number of colonies and types of organisms were recorded. Glove perforation was assessed using the water test. The incidence of perforation and contamination was significantly lower in the study group compared with the control group. Changing gloves at regular intervals is an effective way to decrease the incidence of glove perforation and bacterial contamination during total hip arthroplasty. 相似文献
998.
Impact of the expanded criteria donor allocation system on the use of expanded criteria donor kidneys 总被引:10,自引:0,他引:10
Sung RS Guidinger MK Lake CD McBride MA Greenstein SM Delmonico FL Port FK Merion RM Leichtman AB 《Transplantation》2005,79(9):1257-1261
BACKGROUND: The U.S. Organ Procurement and Transplantation Network recently implemented a policy allocating expanded criteria donor (ECD) kidneys by waiting time alone. ECD kidneys were defined as having a risk of graft failure > or = 1.7 times that of ideal donors. ECDs include any donor > or = 60 years old and donors 50 to 59 years old with at least two of the following: terminal creatinine >1.5 mg/dL, history of hypertension, or death by cerebrovascular accident. The impact of this policy on use of ECD kidneys is assessed. METHODS: The authors compared use of ECD kidneys recovered in the 18 months immediately before and after policy implementation. Differences were tested using t test and chi2 analyses. RESULTS: There was an 18.3% increase in ECD kidney recoveries and a 15.0% increase in ECD kidney transplants in the first 18 months after policy implementation. ECD kidneys made up 22.1% of all recovered kidneys and 16.8% of all transplants, compared with 18.8% (P<0.001) and 14.5% (P<0.001), respectively, in the prior period. The discard rate was unchanged. The median relative risk (RR) for graft failure for transplanted ECD kidneys was 2.07 versus 1.99 in the prepolicy period (P=not significant); the median RR for procured ECD kidneys was unchanged at 2.16. The percentage of transplanted ECD kidneys with cold ischemia times (CIT) <12 hr increased significantly; the corresponding percentage for CIT > or = 24 hr decreased significantly. CONCLUSIONS: The recent increase in ECD kidney recoveries and transplants appears to be related to implementation of the ECD allocation system. 相似文献
999.
Recent advances in iron oxide nanocrystal technology for medical imaging 总被引:25,自引:0,他引:25
Superparamagnetic iron oxide particles (SPIO and USPIO) have a variety of applications in molecular and cellular imaging. Most of the recent research has concerned cellular imaging with imaging of in vivo macrophage activity. According to the iron oxide nanoparticle composition and size which influence their biodistribution, several clinical applications are possible: detection liver metastases, metastatic lymph nodes, inflammatory and/or degenerative diseases. USPIO are investigated as blood pool agents with T1 weighted sequence for angiography, tumour permeability and tumour blood volume or steady-state cerebral blood volume and vessel size index measurements using T2 weighted sequences. Stem cell migration and immune cell trafficking, as well as targeted iron oxide nanoparticles for molecular imaging studies, are at the stage of proof of concept, mainly in animal models. 相似文献
1000.
JL.?NovellaEmail author F.?Boyer C.?Jochum N.?Jovenin I.?Morrone D.?Jolly S.?Bakchine F.?Blanchard 《Quality of life research》2006,15(5):811-819
Objective: The purpose of the present study was to examine the level of agreement between health status ratings provided by patients
with Alzheimer’s disease and by their proxies. Background: Because proxy-completed responses are often necessary in assessing health outcomes for the elderly, it is necessary to determine
the feasibility and potential limitations of using proxies as a patient substitutes. Methods: To assess the potential utility of proxy responses on health status when subjects present a cognitive impairment, this study
compared the responses of 70 subjects with Alzheimer‘s disease and those of their family and/or care provider proxy using
the SF-36. Agreement between proxies and patients was measured by intraclass correlation coefficients (ICCs). Results: The proportion of exact agreement between patients and proxies on the 36 items ranged from 3.3 to 41.7%. Results reveal
poor to moderate agreement between patient and proxy reports. Proxy reliability varied according to the relationship of the
proxy to the index subject. Agreement decreased significantly with increasing severity of dementia and with increasing severity
of Physical status (Katz ADL). Agreement was better for measures of functions that are directly observable and relatively
poor for more subjective measures. Conclusions: Our results confirm the importance of the information source used for patient health status. 相似文献