全文获取类型
收费全文 | 222571篇 |
免费 | 5358篇 |
国内免费 | 50篇 |
专业分类
耳鼻咽喉 | 1687篇 |
儿科学 | 7998篇 |
妇产科学 | 4098篇 |
基础医学 | 22751篇 |
口腔科学 | 2603篇 |
临床医学 | 17894篇 |
内科学 | 39636篇 |
皮肤病学 | 1400篇 |
神经病学 | 21399篇 |
特种医学 | 10887篇 |
外国民族医学 | 4篇 |
外科学 | 35320篇 |
综合类 | 3080篇 |
一般理论 | 36篇 |
预防医学 | 22698篇 |
眼科学 | 3990篇 |
药学 | 12647篇 |
2篇 | |
中国医学 | 683篇 |
肿瘤学 | 19166篇 |
出版年
2021年 | 730篇 |
2020年 | 410篇 |
2019年 | 706篇 |
2018年 | 22601篇 |
2017年 | 17919篇 |
2016年 | 20070篇 |
2015年 | 1630篇 |
2014年 | 1791篇 |
2013年 | 2311篇 |
2012年 | 9070篇 |
2011年 | 23158篇 |
2010年 | 19948篇 |
2009年 | 12556篇 |
2008年 | 21330篇 |
2007年 | 23745篇 |
2006年 | 2535篇 |
2005年 | 4025篇 |
2004年 | 5195篇 |
2003年 | 6017篇 |
2002年 | 4220篇 |
2001年 | 1823篇 |
2000年 | 2005篇 |
1999年 | 1548篇 |
1998年 | 738篇 |
1997年 | 710篇 |
1996年 | 564篇 |
1995年 | 563篇 |
1994年 | 499篇 |
1993年 | 407篇 |
1992年 | 1220篇 |
1991年 | 1260篇 |
1990年 | 1218篇 |
1989年 | 1179篇 |
1988年 | 974篇 |
1987年 | 1080篇 |
1986年 | 983篇 |
1985年 | 1010篇 |
1984年 | 789篇 |
1983年 | 650篇 |
1982年 | 426篇 |
1981年 | 375篇 |
1980年 | 409篇 |
1979年 | 716篇 |
1978年 | 535篇 |
1977年 | 453篇 |
1976年 | 472篇 |
1975年 | 404篇 |
1974年 | 550篇 |
1973年 | 463篇 |
1972年 | 386篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
As the biological width is established around neighboring implants, there is a flattening of the interimplant bone and a change in the position of the soft tissue. As a result, a normal progression of papilla from natural teeth through the adjacent implant area is lost. This presentation describes various techniques and strategies to improve the aesthetic outcome of anterior implant restorations, together with the use of a scalloped implant designed to sustain the interdental bony peaks, and in doing so, maintain the interimplant papillae. 相似文献
102.
Antigenic evidence for simultaneous expression of two different lipooligosaccharides by some strains of Haemophilus influenzae type b. 总被引:8,自引:5,他引:3
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
C C Patrick S E Pelzel E E Miller E Haanes-Fritz J D Radolf P A Gulig G H McCracken Jr E J Hansen 《Infection and immunity》1989,57(7):1971-1978
Isolates of Haemophilus influenzae type b (Hib) can be divided into three antigenic groups based on their reactivities with a set of two monoclonal antibodies (MAbs) directed against epitopes in the oligosaccharide region of Hib lipooligosaccharide (LOS) (P. A. Gulig, C. C. Patrick, L. Hermanstorfer, G. H. McCracken, Jr., and E. J. Hansen, Infect. Immun. 55:513-520, 1987). Approximately 24% of Hib strains react with both of these LOS-specific MAbs. Immunoprecipitation experiments involving several of these strains indicated that the epitopes recognized by these MAbs resided in two different LOS molecules, both of which were synthesized by these particular Hib strains. In addition, Western blot (immunoblot) analysis of proteinase K-treated cell extracts of these strains that had been subjected to sodium dodecyl sulfate-polyacrylamide gradient gel electrophoresis revealed two different LOS staining patterns when they were probed independently with the two MAbs. Colony blot radioimmunoassay of hundreds of colonies of one of these Hib strains showed that each colony bound both MAbs. Immune electron microscopy confirmed that individual cells of this same Hib strain expressed both types of LOS molecule at the same time. An antibody accessibility radioimmunoassay was used to show that different Hib strains of this type varied in the relative amounts of each of the two MAbs that they could bind to their cell surfaces. These findings indicate that some Hib strains can synthesize two antigenically distinct LOS molecules simultaneously. 相似文献
103.
In a study of rock music preferences, listening/watching behavior, and views on destructive rock lyrics, 894 adolescents in grades 9 through 12 in rural, urban, suburban public, and metropolitan parochial schools were administered a questionnaire. Demographic information on parents was also collected. It was found that 17.5% of the students were fans of rock music with lyrics that promote homicide, suicide, or satanic practices (HSSR). Loglinear and multiple regression analyses were used to analyze the data. Parents' marital status, student sex, race, and school environment (urban, rural, suburban, etc.) were found to be significant predictors of HSSR status. As compared with non-HSSR fans, the HSSR fans were more likely to have parents who were “Never married” or “Remarried” and less likely to have parents in the “married” category. The HSSR fans were more likely to be male, white, and enrolled in urban schools but not parochial schools than expected; HSSR status also significantly predicted other music-related attitudes and behaviors. The HSSR fans reported liking both the sound and the lyrics of rock music more often than did non-HSSR fans, as did females and urban students. The HSSR fans more often felt that children under 10 years of age should be allowed to listen to HSSR lyrics, and they more frequently expressed the conviction that HSSR music does not affect adolescents' homicidal or self-destructive behavior. The HSSR fans and females reported more nearly complete knowledge of lyrics than did non-HSSR fans and males. The HSSR fans reported that they watch more MTV than did any other group except rural students. 相似文献
104.
John P Elliott Hugh S Miller Suzanne Coleman Debbie Rhea Diana Abril Karen Hallbauer Niki B Istwan Gary J Stanziano 《Journal of perinatology》2005,25(10):626-630
OBJECTIVE: To assess the impact of activity restriction (AR) on the incidence of preterm birth in women treated for preterm labor testing negative for fetal fibronectin (fFN). STUDY DESIGN: Women who were diagnosed with preterm labor and tocolyzed with magnesium sulfate were concurrently screened with fFN for the purpose of subsequent management. Included were consenting patients with negative fFN, gestational age 23 0/7-33 6/7 weeks, cervical dilation < or =3 cm, and minimal vaginal bleeding. Patients were randomized to AR or no AR. Primary study outcome was incidence of preterm delivery and interval from randomization to delivery. RESULTS: A total of 73 women with negative fFN were randomized (36 with AR, 37 without AR). The overall preterm birth rate was 40%, with 44.4% of patients with AR and 35.1% of patients without AR delivering preterm, p=0.478. CONCLUSION: Maternal AR did not impact pregnancy outcome. The incidence of preterm birth in symptomatic women testing fFN negative was higher than previously reported. 相似文献
105.
106.
107.
Chad G. Ball Andrew W. Kirkpatrick Matthew Smith Robert H. Mulloy Leonard Tse Ian B. Anderson 《European journal of trauma and emergency surgery》2007,33(5):550-552
Abstract We report a case of SMV injury in a critically ill patient. The patient was a 19-year-old woman involved in a motor vehicle
collision. Her injuries included grade II splenic and renal lacerations, devascularized and lacerated right and transverse
colon, a transected transverse mesocolon, a massive shear injury of her abdominal wall, and two partial SMV transections.
At initial damage control laparotomy, the SMV was ligated, the devascularized bowel resected and a temporary abdominal closure
applied. At re-operation, a mesocaval shunt using saphenous vein was employed. The shunt failed and the patient required a
saphenous vein jump graft. Although visceral vascular injuries are rare, ligation of the SMV in a damage control situation
is acceptable. This case study is the first to discuss appropriate treatment when interruption to a patient's collateral visceral
venous drainage limits the surgeon’s ability to ligate. In these situations, bypass shunts may be successful. 相似文献
108.
Henry Cisneros 《AIDS and behavior》2007,11(2):7-8
For persons battling HIV/AIDS a stable place to live may decide the length and quality of life itself. It is nearly impossible for a person on the streets to engage in a needed continuous AIDS treatment regimen when the very basic question of where that person will rest his or her head when darkness comes in just a few hours is unresolved. When danger lurks on the streets, when cold numbs the limbs, when tiredness overwhelms the mind, when fear breaks the spirit, a place to call home would make all the difference. 相似文献
109.
Hoon-Chul Kang Ji Won Kwon Young Mock Lee Heung Dong Kim Hong Jin Lee Si Houn Hahn 《Child's nervous system》2007,23(11):1301-1307
OBJECTIVES: This study sought to characterize epileptic phenotypes in children with nonspecific mitochondrial disease (MD) and to evaluate MD diagnostic approaches. METHODS: A retrospective analysis of the medical, electroencephalogram, and laboratory records of 142 patients with epilepsy was performed. The patients were evaluated for MD, and 124 patients were included in the final cohort. The MD criteria used included an oral glucose lactate stimulation test (OGLST) and urine organic acid/plasma amino acid (UOA/PAA) assays as metabolic indicators of modified Walker criteria, as suggested by Bernier et al. (Neurology 59:1406-1411, 2002). RESULTS: Twenty-two patients were classified as having definite MD (9), probable MD (5), possible MD (6), or pyruvate dehydrogenase (PDH) deficiency (3), including one patient which showed a respiratory chain (RC) defect and PDH deficiency. Seven out of eight patients in whom significant RC defects were observed showed complex I defects. In 14 patients, epileptic seizures start at infantile ages. Of 17 patients who substantially presented generalized seizures, 4 patients started with partial seizures. Five patients consistently presented only partial seizures. The OGLST and UOA/PAA assays were useful for a more precise diagnosis of MD, although low positive predictive value of the OGLST was regrettable. No patient was classified as definite MD by Walker's original criteria, but the use of our revised MD criteria resulted in the classification of nine additional patients as definite MD. CONCLUSIONS: MD manifested considerable diverse epileptic phenotypes and should be considered in the differential diagnosis of epilepsy in children with unexplained encephalomyopathy and progressive and fluctuating clinical courses. 相似文献
110.