全文获取类型
收费全文 | 5402篇 |
免费 | 457篇 |
国内免费 | 28篇 |
专业分类
耳鼻咽喉 | 55篇 |
儿科学 | 220篇 |
妇产科学 | 108篇 |
基础医学 | 710篇 |
口腔科学 | 104篇 |
临床医学 | 495篇 |
内科学 | 1178篇 |
皮肤病学 | 204篇 |
神经病学 | 444篇 |
特种医学 | 399篇 |
外科学 | 830篇 |
综合类 | 27篇 |
预防医学 | 424篇 |
眼科学 | 66篇 |
药学 | 282篇 |
中国医学 | 5篇 |
肿瘤学 | 336篇 |
出版年
2023年 | 38篇 |
2022年 | 44篇 |
2021年 | 138篇 |
2020年 | 72篇 |
2019年 | 125篇 |
2018年 | 156篇 |
2017年 | 101篇 |
2016年 | 102篇 |
2015年 | 126篇 |
2014年 | 180篇 |
2013年 | 214篇 |
2012年 | 279篇 |
2011年 | 277篇 |
2010年 | 165篇 |
2009年 | 160篇 |
2008年 | 214篇 |
2007年 | 242篇 |
2006年 | 214篇 |
2005年 | 235篇 |
2004年 | 200篇 |
2003年 | 196篇 |
2002年 | 174篇 |
2001年 | 143篇 |
2000年 | 139篇 |
1999年 | 129篇 |
1998年 | 140篇 |
1997年 | 106篇 |
1996年 | 106篇 |
1995年 | 81篇 |
1994年 | 94篇 |
1993年 | 90篇 |
1992年 | 90篇 |
1991年 | 97篇 |
1990年 | 88篇 |
1989年 | 106篇 |
1988年 | 91篇 |
1987年 | 103篇 |
1986年 | 78篇 |
1985年 | 83篇 |
1984年 | 62篇 |
1983年 | 48篇 |
1982年 | 41篇 |
1981年 | 44篇 |
1980年 | 38篇 |
1979年 | 28篇 |
1978年 | 33篇 |
1977年 | 34篇 |
1976年 | 32篇 |
1975年 | 26篇 |
1972年 | 17篇 |
排序方式: 共有5887条查询结果,搜索用时 15 毫秒
71.
Huisman JA; Paulussen RJ; Geurts TB; Odink J; Rekers H 《Human reproduction (Oxford, England)》1997,12(1):34-38
The objective was to demonstrate bioequivalence between s.c. and i.m.
administration of Humegon (FSH/LH ratio 1:1) and Normegon (FSH/LH ratio
3:1). In two randomized, single-centre, cross-over studies, 18 healthy
volunteers on each formulation were assigned to one of the two
administration sequences. Subjects were given single doses of one of the
above gonadotrophins after endogenous gonadotrophin production had first
been suppressed using high-dose oral contraceptive. Subsequently, rate
(Cmax, tmax) and extent (AUC) of absorption of follicle stimulating hormone
(FSH) and luteinizing hormone (LH) were determined for 14 days. For Cmax
and AUC, analysis of variance (ANOVA) was performed on log-transformed data
and for tmax ANOVA was performed on ranks. Intramuscular and s.c.
injections of Humegon were bioequivalent with respect to the main
pharmacokinetic parameters, being AUC and Cmax of FSH absorption.
Intramuscular and s.c. injections of Normegon were bioequivalent with
respect to the AUC of FSH and not bioequivalent with respect to the Cmax of
FSH. For tmax of FSH as well as for most LH variables of both preparations,
bioequivalence could not be proven due to the high intra- and
interindividual variability and/or concentrations being close to the
detection limit. Thus, the main pharmacokinetic FSH variables after i.m.
and s.c. administration of Humegon and Normegon were bioequivalent.
相似文献
72.
Molecular cloning and characterization of the 120-kilodalton protein gene of Ehrlichia canis and application of the recombinant 120-kilodalton protein for serodiagnosis of canine ehrlichiosis 下载免费PDF全文
The 120-kDa outer membrane protein (p120) is a potential adhesin of Ehrlichia chaffeensis, and recombinant p120 is very useful for serodiagnosis of human monocytotropic ehrlichiosis. The analogous gene of p120 in Ehrlichia canis was cloned, sequenced, and expressed. Like the E. chaffeensis p120, the E. canis p120 contains tandem repeat units. However, neither the repeat number nor the amino acid sequences in the repeats are identical in the two Ehrlichia species. The repeat units are hydrophilic and by probability analysis are predicted to be surface exposed in both species. The repeat regions of the p120s of the two species have common amino acid sequences that are predicted to be surface exposed. The overall amino acid sequence of the E. canis p120 is 30% homologous to that of E. chaffeensis p120. Protein immunoblotting demonstrated that the recombinant E. canis p120 reacted with convalescent sera from dogs with canine ehrlichiosis. These results indicate that the recombinant p120 is a potential antigen for the serodiagnosis of canine ehrlichiosis. 相似文献
73.
Sciamanna CN Clark MA Diaz JA Newton S 《International journal of medical informatics》2003,72(1-3):1-8
BACKGROUND: Millions of people use the Internet as a source for health information yet little is understood about how the use of the Internet for health information is related to the doctor-patient relationship. OBJECTIVE: We conducted the present study to understand the association between one's interest in using the Internet for general and quality-oriented health information and attitudes about one's communications with health care provider(s). DESIGN: Cross-sectional survey. SETTING: Four community-based primary care practices in Rhode Island. MEASUREMENTS: A single self-administered survey included items to measure: interest in using the Internet to look for general and quality-oriented information and a patient's perceptions of the degree to which their doctors over the previous year have: (1) given them information and (2) engaged them in the decision-making process. RESULTS: A total of 300 patients completed the survey. Among patients without Internet access, interest in using the Internet for health related activities was less among patients who felt that their doctor gave less information: Odds ratio 0.83 (95% CI, 0.70-0.98) and greater among patients who felt that their doctor engaged them more in decision making: Odds ratio 1.3 (95% CI, 1.1-1.6). Among patients with Internet access, we found no relationship between interest in using the Internet for health related activities and measures of patient-physician communication or patient-physician decision making. CONCLUSIONS: Interest in using the Internet for health information is greater for those who (1) felt their doctors provided less information and (2) felt their doctors engaged them more in the decision-making process, but this is true only for those without access to the Internet. 相似文献
74.
The effects of sleep posture and sleep stage on apnea frequency 总被引:6,自引:0,他引:6
The Apnea Plus Hypopnea Index (A + HI) of 60 male positional sleep apneics was analyzed by sleep stage to determine if positional differences are limited to NREM sleep. Differences in apnea severity by sleep position were found to persist in REM sleep and to be of equal extent to those differences found in NREM sleep, despite the fact that there is also a significant increase in the frequency of apneic events associated with REM sleep. The positional effect persists in REM sleep, making treatments to control sleep posture a viable option. 相似文献
75.
Lesions of the articular surfaces of the knee have been managed by various techniques over the last 50 years. Surgical management has involved: excising the damaged area, refashioning the underlying bone to produce a fibrous response, and introducing allograft, autograft and synthetic materials to encourage a repair matrix. The techniques and their pitfalls are reviewed and discussed, and suggestions made as to the direction of future studies for the repair of osteochondral lesions in the painful knee. 相似文献
76.
The sudden death of five sulphur-crested cockatoos (Cacatua galerita) with no apparent clinical signs was investigated. The birds had hepatitis with intranuclear inclusion bodies (IIBs), as well as IIBs in mononuclear spleen cells, epithelial cells of the kidney tubules and endothelial cells of the glomerular capillaries. Ultrastructurally, icosahedral herpesvirus-like particles, 110 to 115 nm in diameter were found consistent with Pacheco's disease. This is the first time the disease has been reported in cockatoos in Spain. 相似文献
77.
Hoover EL Hsu HK Diaz C Khan R Reddy CV Gross AM Webb H El-Sherif N Griepp RB 《Texas Heart Institute journal / from the Texas Heart Institute of St. Luke's Episcopal Hospital, Texas Children's Hospital》1985,12(2):187-193
One-stage surgery was successfully performed in a 44-year-old hypertensive man with uncontrolled angina, multiple coarctations of the thoracic and abdominal aorta, and a previous subtotal gastrectomy. There was a gradient of 120 mm Hg between the thoracic and abdominal aorta. A graft was placed retroperitoneally from the infrarenal aorta to the ascending aorta and was followed by a coronary artery bypass graft. Twenty-four months postoperatively, the patient was free of angina, and his hypertension was easily controlled. 相似文献
78.
A sialic acid-specific O-acetylesterase in human erythrocytes: possible identity with esterase D, the genetic marker of retinoblastomas and Wilson disease. 总被引:2,自引:2,他引:0 下载免费PDF全文
A Varki E Muchmore S Diaz 《Proceedings of the National Academy of Sciences of the United States of America》1986,83(4):882-886
The "nonspecific" esterases are a family of enzymes that were originally identified because of their reaction with synthetic O-acetyl ester substrates. While the electrophoretic polymorphisms of these enzymes have been extremely useful for genetic studies, their biological functions have remained completely unknown. Esterase D is characterized by its reactivity with 4-methylumbelliferyl acetate. This enzyme has recently been of particular interest because of its tight linkage to the putative recessive gene causing retinoblastomas, and to the recessive gene causing Wilson disease. We describe here the partial purification of a human erythrocyte esterase that appears to be highly specific for O-acetylated sialic acids. We next present evidence that suggests that esterase D is identical to this sialic acid-specific O-acetylesterase. First, both activities copurify from human erythrocyte lysates through several different purification steps, each of which use different principles of separation. Second, both activities show a remarkably similar profile of inhibition with a variety of different agents. Third, they both show a nearly identical heat-inactivation profile. This cytosolic sialic acid-specific O-acetylesterase appears to be involved in the "recycling" of O-acetylated sialic acid molecules. Thus, esterase D may be the first nonspecific esterase for which a specific biological role can be predicted. 相似文献
79.
Power Thomas G. Garcia Karina Silva Martinez AnaMaria Diaz Parker Louise A. Hidalgo-Mendez Jackelyn Ramos Guadalupe 《Prevention science》2022,23(6):1018-1028
Prevention Science - “Madres Apoyando el Desarrollo Emocional de Sus Hijos” (“Mothers Supporting the Emotional Development of Their Children”) is a parenting... 相似文献
80.
André Luís Conde Watanabe Mateus Silva Feijó Vinícius Paulo Lima de Menezes Mayara Regina Galdino-Vasconcelos Jorge Luis Salinas Caballero Gustavo Ferreira Fernando Jorge Natália Trevizoli Luiz Gustavo Diaz Priscila Brizolla de Campos Gabriel Cajá Raquel Ullmann Ana Virgínia Figueira Tiago Morato Adriano Moraes Juan Rafael Branez Pereira Marcelo Perosa 《Transplantation proceedings》2021,53(1):73-82
IntroductionLiver transplantation is the standard treatment for end-stage liver disease. Brazil holds the third highest number of liver transplants performed per year, but center maldistribution results in high discrepancies in accessing this treatment. In 2012, an interstate partnership successfully implemented a new liver transplantation program in the middle west of Brazil. Here, we report the results of the first 500 liver transplants performed in this new program and discuss the impacts of a new transplant center in regional transplantation dynamics.MethodsWe reviewed data from the first 500 consecutive deceased donor liver transplants performed in the new program during an 8-year period. We analyzed data on patients’ clinical and demographic profiles, postoperative outcomes, and graft and recipient survival rates. Univariate survival analysis was conducted using log-rank tests to compare the groups.ResultsAlmost half (48%) of the procured organs and 40% of the recipients transplanted in our center were from outside our state. Recipient 30-day mortality was 9%. Overall recipient survival at 1 year and 5 years was 85% and 80%, respectively. Mortality was significantly associated with higher Model for End-Stage Liver Disease (P < .001) but not with the presence of hepatocellular carcinoma (P = .795).DiscussionThe new transplantation program treated patients from different regions of Brazil and became the reference center in liver transplantation for the middle west region. Despite the recent implementation, our outcomes are comparable to experienced centers around the world. This model can inspire the creation of new transplantation programs aiming to democratize access to liver transplantation nationwide. 相似文献