全文获取类型
收费全文 | 3672篇 |
免费 | 302篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 17篇 |
儿科学 | 97篇 |
妇产科学 | 84篇 |
基础医学 | 454篇 |
口腔科学 | 54篇 |
临床医学 | 483篇 |
内科学 | 589篇 |
皮肤病学 | 43篇 |
神经病学 | 420篇 |
特种医学 | 129篇 |
外科学 | 507篇 |
综合类 | 112篇 |
一般理论 | 1篇 |
预防医学 | 363篇 |
眼科学 | 128篇 |
药学 | 269篇 |
1篇 | |
肿瘤学 | 233篇 |
出版年
2023年 | 11篇 |
2022年 | 52篇 |
2021年 | 109篇 |
2020年 | 59篇 |
2019年 | 103篇 |
2018年 | 131篇 |
2017年 | 82篇 |
2016年 | 81篇 |
2015年 | 85篇 |
2014年 | 129篇 |
2013年 | 218篇 |
2012年 | 268篇 |
2011年 | 288篇 |
2010年 | 171篇 |
2009年 | 143篇 |
2008年 | 234篇 |
2007年 | 210篇 |
2006年 | 208篇 |
2005年 | 173篇 |
2004年 | 174篇 |
2003年 | 173篇 |
2002年 | 142篇 |
2001年 | 42篇 |
2000年 | 35篇 |
1999年 | 30篇 |
1998年 | 18篇 |
1997年 | 20篇 |
1996年 | 17篇 |
1995年 | 21篇 |
1994年 | 27篇 |
1993年 | 13篇 |
1992年 | 22篇 |
1991年 | 30篇 |
1990年 | 22篇 |
1989年 | 17篇 |
1988年 | 23篇 |
1987年 | 28篇 |
1986年 | 28篇 |
1985年 | 26篇 |
1984年 | 25篇 |
1983年 | 20篇 |
1982年 | 23篇 |
1981年 | 17篇 |
1980年 | 14篇 |
1979年 | 17篇 |
1978年 | 12篇 |
1972年 | 11篇 |
1970年 | 14篇 |
1969年 | 10篇 |
1967年 | 12篇 |
排序方式: 共有3984条查询结果,搜索用时 531 毫秒
11.
12.
13.
14.
PURPOSE: The purpose of this study was to examine the predictive validity of a collection of prelinguistic skills measured longitudinally in the 2nd year of life to language outcome in the 3rd year in children with typical language development. METHOD: A collection of prelinguistic skills was assessed in 160 children early (M = 14.31 months; SD = 1.36) and late (M = 19.76 months; SD = 1.16) in their 2nd year by using the Communication and Symbolic Behavior Scales Developmental Profile Behavior Sample (A. Wetherby & B. Prizant, 2002). The relation between the prelinguistic skills and the receptive and expressive language near the 3rd birthday was examined. RESULTS: Significant correlations were observed between many prelinguistic skills and language outcome. Regression analyses indicated that comprehension both early and late contributed unique variance to receptive and expressive language outcome. In addition, early in the 2nd year, inventory of conventional gestures contributed uniquely to receptive language outcome, and acts for joint attention contributed uniquely to expressive outcome. Late in the 2nd year, inventory of consonants contributed uniquely to expressive outcome. CONCLUSIONS: The findings demonstrate continuity between prelinguistic and linguistic skills and how individual differences in a number of prelinguistic skills contribute collectively and uniquely to language outcome in typically developing children. 相似文献
15.
Analysis of orthologous gene expression between human pulmonary adenocarcinoma and a carcinogen-induced murine model 下载免费PDF全文
Stearman RS Dwyer-Nield L Zerbe L Blaine SA Chan Z Bunn PA Johnson GL Hirsch FR Merrick DT Franklin WA Baron AE Keith RL Nemenoff RA Malkinson AM Geraci MW 《The American journal of pathology》2005,167(6):1763-1775
Human adenocarcinoma (AC) is the most frequently diagnosed human lung cancer, and its absolute incidence is increasing dramatically. Compared to human lung AC, the A/J mouse-urethane model exhibits similar histological appearance and molecular changes. We examined the gene expression profiles of human and murine lung tissues (normal or AC) and compared the two species' datasets after aligning approximately 7500 orthologous genes. A list of 409 gene classifiers (P value <0.0001), common to both species (joint classifiers), showed significant, positive correlation in expression levels between the two species. A number of previously reported expression changes were recapitulated in both species, such as changes in glycolytic enzymes and cell-cycle proteins. Unexpectedly, joint classifiers in angiogenesis were uniformly down-regulated in tumor tissues. The eicosanoid pathway enzymes prostacyclin synthase (PGIS) and inducible prostaglandin E(2) synthase (PGES) were joint classifiers that showed opposite effects in lung AC (PGIS down-regulated; PGES up-regulated). Finally, tissue microarrays identified the same protein expression pattern for PGIS and PGES in 108 different non-small cell lung cancer biopsies, and the detection of PGIS had statistically significant prognostic value in patient survival. Thus, the A/J mouse-urethane model reflects significant molecular details of human lung AC, and comparison of changes in orthologous gene expression may provide novel insights into lung carcinogenesis. 相似文献
16.
The clinical-grade 42-kilodalton fragment of merozoite surface protein 1 of Plasmodium falciparum strain FVO expressed in Escherichia coli protects Aotus nancymai against challenge with homologous erythrocytic-stage parasites 总被引:4,自引:0,他引:4 下载免费PDF全文
Darko CA Angov E Collins WE Bergmann-Leitner ES Girouard AS Hitt SL McBride JS Diggs CL Holder AA Long CA Barnwell JW Lyon JA 《Infection and immunity》2005,73(1):287-297
A 42-kDa fragment from the C terminus of major merozoite surface protein 1 (MSP1) is among the leading malaria vaccine candidates that target infection by asexual erythrocytic-stage malaria parasites. The MSP1(42) gene fragment from the Vietnam-Oak Knoll (FVO) strain of Plasmodium falciparum was expressed as a soluble protein in Escherichia coli and purified according to good manufacturing practices. This clinical-grade recombinant protein retained some important elements of correct structure, as it was reactive with several functional, conformation-dependent monoclonal antibodies raised against P. falciparum malaria parasites, it induced antibodies (Abs) that were reactive to parasites in immunofluorescent Ab tests, and it induced strong growth and invasion inhibitory antisera in New Zealand White rabbits. The antigen quality was further evaluated by vaccinating Aotus nancymai monkeys and challenging them with homologous P. falciparum FVO erythrocytic-stage malaria parasites. The trial included two control groups, one vaccinated with the sexual-stage-specific antigen of Plasmodium vivax, Pvs25, as a negative control, and the other vaccinated with baculovirus-expressed MSP1(42) (FVO) as a positive control. Enzyme-linked immunosorbent assay (ELISA) Ab titers induced by E. coli MSP1(42) were significantly higher than those induced by the baculovirus-expressed antigen. None of the six monkeys that were vaccinated with the E. coli MSP1(42) antigen required treatment for uncontrolled parasitemia, but two required treatment for anemia. Protective immunity in these monkeys correlated with the ELISA Ab titer against the p19 fragment and the epidermal growth factor (EGF)-like domain 2 fragment of MSP1(42), but not the MSP1(42) protein itself or the EGF-like domain 1 fragment. Soluble MSP1(42) (FVO) expressed in E. coli offers excellent promise as a component of a vaccine against erythrocytic-stage falciparum malaria. 相似文献
17.
K. B. Carter J. K. Drury J. R. Richards 《Medical & biological engineering & computing》1976,14(4):465-470
Calorimetry, using the gradient layer technique, has become well established in the study of energy metabolism. The use of a commercially constructed gradient layer box within a calorimetry system designed to measure directly and indirectly the metabolic sequelae of thermal injury in rats, is described. Variations in the signal output were discovered. These were found to be dependent upon:
- stability of the ambient temperature
- stability of the gradient layer box water jacket temperature
- position and size of the calibrating heat source.
18.
Differences in host susceptibility to disease progression in the human challenge model of Haemophilus ducreyi infection 下载免费PDF全文
Spinola SM Bong CT Faber AL Fortney KR Bennett SL Townsend CA Zwickl BE Billings SD Humphreys TL Bauer ME Katz BP 《Infection and immunity》2003,71(11):6658-6663
With human volunteers inoculated at two sites with Haemophilus ducreyi, outcomes for a subject were not independent. In a reinfection trial, 2 of 11 previous pustule formers and 6 of 10 previous resolvers resolved all sites of infection. There was no correlation between serum bactericidal or phagocytic activity and outcome in the trial. These data indicate that different hosts are differentially susceptible to disease progression versus resolution in the model. 相似文献
19.
Chatterjea D Burns-Guydish SM Sciuto TE Dvorak A Contag CH Galli SJ 《Immunology letters》2005,99(1):122-129
Mast cells are important effector cells in IgE-associated immune responses, but also can contribute to host defense in certain examples of bacterial infection. We found that genetically mast cell-deficient WBB6F1-Kit(W)/Kit(W-v) mice exhibited more bacterial CFUs per spleen by 6 days after intraperitoneal injection of bioluminescent Salmonella typhimurium, and died more rapidly after infection, than did the congenic WBB6F1-Kit(+/+) wild type mice. Adoptive transfer of bone marrow-derived cultured mast cells of Kit(+/+) origin to the peritoneal cavity of Kit(W)/Kit(W-v) mice resulted in engraftment of mast cells in the peritoneal cavity and mesentery of the recipient mice, and the development of large numbers of mast cells in the spleen. However, such mast cell-engrafted Kit(W)/Kit(W-v) mice appeared sicker after intraperitoneal injection with S. typhimurium than did mast cell-deficient Kit(W)/Kit(W-v) mice, and exhibited numbers of CFUs of bacteria per spleen, and a survival curve, that were not significantly different than those of Kit(W)/Kit(W-v) mice. These results, when taken together with prior studies investigating the roles of mast cells in innate immunity, strongly suggest that whether mast cells can be shown to have a significant role in enhancing survival during bacterial infections may depend critically on the details of the particular experimental systems examined. 相似文献
20.
Toni Marie Torres-McGehee Dawn M. Emerson Erin M. Moore Stacy E. Walker Kelly Pritchett Allison B. Smith Taylor A. Lyles Greg Wakefield Kacey Ohlemeyer 《Journal of Athletic Training》2021,56(3):311
ContextResearch exists on energy balances (EBs) and eating disorder (ED) risks in physically active populations and occupations by settings, but the EB and ED risk in athletic trainers (ATs) have not been investigated.ObjectiveTo assess ATs'' energy needs, including the macronutrient profile, and examine ED risk and pathogenic behavioral differences between sexes (men, women) and job statuses (part time or full time) and among settings (college or university, high school, nontraditional).DesignCross-sectional study.SettingFree living in job settings.Patients or Other ParticipantsAthletic trainers (n = 46; male part-time graduate assistant ATs = 12, male full-time ATs = 11, female part-time graduate assistant ATs = 11, female full-time ATs = 12) in the southeastern United States.Main Outcome Measure(s)Anthropometric measures (sex, age, height, weight, body composition), demographic characteristics (job status [full- or part-time AT], job setting [college/university, high school, nontraditional], years of AT experience, exercise background, alcohol use), resting metabolic rate, energy intake (EI), total daily energy expenditure (TDEE), EB, exercise energy expenditure, macronutrients (carbohydrates, protein, fats), the Eating Disorder Inventory-3, and the Eating Disorder Inventory-3 Symptom Checklist.ResultsThe majority of participants (84.8%, n = 39) had an ED risk, with 26.1% (n = 12) engaging in at least 1 pathogenic behavior, 50% (n = 23) in 2 pathogenic behaviors, and 10.8% (n = 5) in >2 pathogenic behaviors. Also, 82.6% of ATs (n = 38) presented in negative EB (EI < TDEE). Differences were found in resting metabolic rate for sex and job status (F1,45 = 16.48, P = .001), EI (F1,45 = 12.01, P = .001), TDEE (F1,45 = 40.36, P < .001), and exercise energy expenditure (F1,38 = 5.353, P = .026). No differences were present in EB for sex and job status (F1,45 = 1.751, P = .193); χ2 analysis revealed no significant relationship between ATs'' sex and EB (= 0.0, P = 1.00) and job status and EB ( = 2.42, P = .120). No significant relationship existed between Daily Reference Intakes recommendations for all macronutrients and sex or job status.ConclusionsThese athletic trainers experienced negative EB, similar to other professionals in high-demand occupations. Regardless of sex or job status, ATs had a high ED risk and participated in unhealthy pathogenic behaviors. The physical and mental concerns associated with these findings indicate a need for interventions targeted at ATs'' health behaviors. 相似文献