全文获取类型
收费全文 | 21073篇 |
免费 | 1667篇 |
国内免费 | 49篇 |
专业分类
耳鼻咽喉 | 194篇 |
儿科学 | 686篇 |
妇产科学 | 597篇 |
基础医学 | 2986篇 |
口腔科学 | 260篇 |
临床医学 | 2574篇 |
内科学 | 3923篇 |
皮肤病学 | 367篇 |
神经病学 | 2109篇 |
特种医学 | 621篇 |
外国民族医学 | 5篇 |
外科学 | 2366篇 |
综合类 | 186篇 |
一般理论 | 14篇 |
预防医学 | 2445篇 |
眼科学 | 314篇 |
药学 | 1449篇 |
中国医学 | 19篇 |
肿瘤学 | 1674篇 |
出版年
2024年 | 34篇 |
2023年 | 258篇 |
2022年 | 470篇 |
2021年 | 872篇 |
2020年 | 461篇 |
2019年 | 836篇 |
2018年 | 916篇 |
2017年 | 630篇 |
2016年 | 681篇 |
2015年 | 751篇 |
2014年 | 1013篇 |
2013年 | 1161篇 |
2012年 | 1769篇 |
2011年 | 1805篇 |
2010年 | 885篇 |
2009年 | 762篇 |
2008年 | 1273篇 |
2007年 | 1228篇 |
2006年 | 1131篇 |
2005年 | 1078篇 |
2004年 | 982篇 |
2003年 | 786篇 |
2002年 | 704篇 |
2001年 | 155篇 |
2000年 | 155篇 |
1999年 | 154篇 |
1998年 | 166篇 |
1997年 | 112篇 |
1996年 | 100篇 |
1995年 | 92篇 |
1994年 | 75篇 |
1993年 | 68篇 |
1992年 | 89篇 |
1991年 | 98篇 |
1990年 | 75篇 |
1989年 | 78篇 |
1988年 | 93篇 |
1987年 | 75篇 |
1986年 | 64篇 |
1985年 | 69篇 |
1984年 | 64篇 |
1983年 | 47篇 |
1982年 | 40篇 |
1981年 | 30篇 |
1980年 | 33篇 |
1979年 | 40篇 |
1978年 | 26篇 |
1977年 | 25篇 |
1976年 | 35篇 |
1972年 | 25篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
Infant rats exhibit sensitive-period odor learning characterized by olfactory bulb neural changes and odor preference acquisitions critical for survival. This sensitive period is coincident with low endogenous corticosterone (CORT) levels and stress hyporesponsivity. The authors hypothesized that low corticosterone levels modulate sensitive-period learning. They assessed the effects of manipulating CORT levels by increasing and removing CORT during (Postnatal Day 8) and after (Postnatal Day 12) the sensitive period. Results show that (a) exogenous CORT prematurely ends sensitive-period odor-shock-induced preferences; (b) adrenalectomy developmentally extends the sensitive period as indicated by odor-shock-induced odor-preference learning in older pups, whereas CORT replacement can reinstate fear learning; and (c) CORT manipulation modulates olfactory bulb correlates of sensitive-period odor learning in a manner consistent with behavior. 相似文献
92.
Barton A Lamb R Symmons D Silman A Thomson W Worthington J Donn R 《Genes and immunity》2003,4(7):487-491
The aim of the study was to investigate whether polymorphisms of macrophage migration inhibitory factor (MIF) determine susceptibility to or severity of inflammatory polyarthritis (IP). Genotypes for a single-nucleotide polymorphism (MIF-173*G/C) and a tetranucleotide (CATT)(n) repeat mapping to the promoter region of the MIF gene were compared between UK Caucasian IP cases (n=438) and controls (n=343). Both polymorphisms were also investigated for association with features of disease activity and severity at baseline and by 5 years. The MIF-173*C allele (OR 1.7, 95% CI 1.3-2.4, P=1.8 x 10(-4)) and the CATT(7) allele (OR 1.5, 95% CI 1.0-2.1, P=0.02) were found to be associated with increased susceptibility to IP. Furthermore, presence of the haplotype containing both associated polymorphisms was associated with a three-fold increase risk of developing IP. No association with disease severity or activity either at baseline or by 5 years was detected for either of the promoter polymorphisms studied. In conclusion, MIF is a susceptibility gene for the development of IP. The same alleles previously reported to be associated with susceptibility to juvenile idiopathic arthritis account for the increased risk. The promoter polymorphisms of MIF, investigated in this study, do not influence the severity of disease outcome by 5 years. 相似文献
93.
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
94.
Stephanie Spranger Matthias Spranger Hans-Michael Meinck Gholamali Tariverdian 《American journal of medical genetics. Part A》1995,57(3):425-428
We report on 2 sisters with an autosomal-recessive multiple pterygium syndrome, type Escobar, consisting of multiple pterygia with severe contractures, short stature, and minor facial and external genital anomalies. The striking finding was severe muscular atrophy. We speculate that a neu-romuscular disorder is the underlying pathogenesis of Escobar syndrome. © 1995 Wiley-Liss, Inc. 相似文献
95.
There are conflicting reports regarding type and extent of the change in couples' lives due to the arrival of a 1st baby. The present short-term longitudinal study of 39 volunteer couples had 2 major objectives: 1) to examine changes in couples' division of labor during the transition to parenthood; and 2) to investigate husband-wife differences in the associations between indices of marital and parental adjustment during the early postpartum months. Individual questionnaires and interviews were administered in couples' homes on 3 occasions: early pregnancy, late pregnancy, and 3-4 months postpartum. The major findings were that changes in household division of labor from early pregnancy to late pregnancy to 3-4 months postpartum demonstrated a curvilinear pattern, such that late pregnancy was characterized by more egalitarian household roles than was found in early pregnancy or postpartum. Marital adjustment mean scores suggested that marriages were functioning well at 3-4 momnths postpartum. Fathers' greater involvement with the baby was associated with better marital and parental adjustment, whereas fathers' postpartum participation in feminine household tasks was correlated with lower adjustment. In contrast to father, mothers' greater participation in baby care tasks was associated with lower marital adjustment. Mothers usually perceived changes in marriage and lifestyle due to the baby as more bothersome than did fathers. Adjustment to parenthood and marital adjustment measures were more interrelated more frequently for fathers than mothers. These findings underscore the complex associations among husbands' and wives' household roles, marital adjustment, involvement with baby, and adjustment to parenthood. 相似文献
96.
Wong Jasin Ezeife Nnaemezie Kudla Angelika Crown Deborah Trierweiler Robert Capraro Pamela Tomazin Stephanie Su Han Pham Tri Heinemann Allen W. 《Journal of occupational rehabilitation》2022,32(3):464-472
Journal of Occupational Rehabilitation - Purpose The COVID-19 pandemic has disproportionately affected the lives of people with disabilities (PWD). How the pandemic affects the employment of PWD... 相似文献
97.
Stephanie Andraos Beatrix Jones Clare Wall Eric Thorstensen Martin Kussmann David Cameron-Smith Katherine Lange Susan Clifford Richard Saffery David Burgner Melissa Wake Justin OSullivan 《Nutrients》2021,13(3)
Scope: B vitamers are co-enzymes involved in key physiological processes including energy production, one-carbon, and macronutrient metabolism. Studies profiling B vitamers simultaneously in parent–child dyads are scarce. Profiling B vitamers in parent–child dyads enables an insightful determination of gene–environment contributions to their circulating concentrations. We aimed to characterise: (a) parent–child dyad concordance, (b) generation (children versus adults), (c) age (within the adult subgroup (age range 28–71 years)) and (d) sex differences in plasma B vitamer concentrations in the CheckPoint study of Australian children. Methods and Results: 1166 children (11 ± 0.5 years, 51% female) and 1324 parents (44 ± 5.1 years, 87% female) took part in a biomedical assessment of a population-derived longitudinal cohort study: The Growing Up in Australia’s Child Health CheckPoint. B vitamer levels were quantified by UHPLC/MS-MS. B vitamer levels were weakly concordant between parent–child pairs (10–31% of variability explained). All B vitamer concentrations exhibited generation-specificity, except for flavin mononucleotide (FMN). The levels of thiamine, pantothenic acid, and 4-pyridoxic acid were higher in male children, and those of pantothenic acid were higher in male adults compared to their female counterparts. Conclusion: Family, age, and sex contribute to variations in the concentrations of plasma B vitamers in Australian children and adults. 相似文献
98.
Maternal and Child Health Journal - The maternal health field has recently focused on the importance of interpersonal quality of care and continues to cite structural deficits as a contributor to... 相似文献
99.
100.
Beomyoung Cho Jana L. Hirschtick Bukola Usidame Rafael Meza Ritesh Mistry Stephanie R. Land David T. Levy Theodore Holford Nancy L. Fleischer 《The Journal of adolescent health》2021,68(4):750-757
PurposeThis study examines sociodemographic patterns of exclusive/dual/polytobacco use among U.S. high school students using multiple national surveys.MethodsUsing three national youth surveys (Population Assessment of Tobacco and Health [PATH] Wave 4 [2016–2017], 2017 Youth Risk Behavior Survey, and 2017 National Youth Tobacco Survey), we classified tobacco products into four groups: (1) electronic nicotine delivery systems (ENDS), (2) conventional cigarettes (CCs), (3) other combustible tobacco products, and (4) smokeless tobacco products. We created 16 categories of non/exclusive/dual/polytobacco use within the past 30 days using the four product groups and calculated weighted population prevalence by sex and race/ethnicity (all surveys) and parental education and income (PATH), based on variable availability.ResultsThe results from 9,331, 12,407, and 9,699 high school students in PATH, Youth Risk Behavior Survey, and National Youth Tobacco Survey, respectively, largely agreed and pointed to similar conclusions. ENDS was the most prevalent exclusive use product (3.8%–5.2% across surveys), with CCs falling to second or third (1.2%–2.0% across surveys). By sex, exclusive, dual, and poly smokeless tobacco product use were more common for males, whereas exclusive CC use was more common for females. By race/ethnicity, non-Hispanic Whites had a higher prevalence of exclusive ENDS use and ENDS/CC dual use than non-Hispanic Blacks. As income and parental education levels increased from low to high, the prevalence of exclusive CC use decreased, whereas the prevalence of exclusive ENDS use increased.ConclusionUnderstanding sociodemographic patterns of tobacco use can help identify groups who may be at greater risk for tobacco-related health outcomes. 相似文献