全文获取类型
收费全文 | 1828篇 |
免费 | 151篇 |
国内免费 | 23篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 55篇 |
妇产科学 | 59篇 |
基础医学 | 244篇 |
口腔科学 | 80篇 |
临床医学 | 151篇 |
内科学 | 305篇 |
皮肤病学 | 61篇 |
神经病学 | 133篇 |
特种医学 | 192篇 |
外科学 | 187篇 |
综合类 | 38篇 |
一般理论 | 3篇 |
预防医学 | 171篇 |
眼科学 | 22篇 |
药学 | 160篇 |
2篇 | |
肿瘤学 | 131篇 |
出版年
2021年 | 16篇 |
2019年 | 16篇 |
2018年 | 29篇 |
2017年 | 21篇 |
2016年 | 27篇 |
2015年 | 32篇 |
2014年 | 29篇 |
2013年 | 50篇 |
2012年 | 68篇 |
2011年 | 60篇 |
2010年 | 39篇 |
2009年 | 46篇 |
2008年 | 64篇 |
2007年 | 74篇 |
2006年 | 70篇 |
2005年 | 66篇 |
2004年 | 56篇 |
2003年 | 55篇 |
2002年 | 42篇 |
2001年 | 41篇 |
2000年 | 55篇 |
1999年 | 38篇 |
1998年 | 43篇 |
1997年 | 44篇 |
1996年 | 37篇 |
1995年 | 32篇 |
1994年 | 36篇 |
1993年 | 38篇 |
1992年 | 42篇 |
1991年 | 38篇 |
1990年 | 37篇 |
1989年 | 71篇 |
1988年 | 60篇 |
1987年 | 54篇 |
1986年 | 54篇 |
1985年 | 55篇 |
1984年 | 40篇 |
1983年 | 25篇 |
1982年 | 20篇 |
1981年 | 19篇 |
1980年 | 21篇 |
1979年 | 20篇 |
1978年 | 17篇 |
1977年 | 24篇 |
1976年 | 18篇 |
1974年 | 13篇 |
1972年 | 10篇 |
1970年 | 9篇 |
1969年 | 9篇 |
1967年 | 10篇 |
排序方式: 共有2002条查询结果,搜索用时 218 毫秒
21.
22.
23.
Antigenic structure and variation of canine parvovirus type-2, feline panleukopenia virus, and mink enteritis virus 总被引:15,自引:0,他引:15
The antigenic structure and variation of canine parvovirus type-2 (CPV), feline panleukopenia virus (FPV), mink enteritis virus (MEV), and a closely related virus of raccoons (RPV) was investigated using a panel of 13 monoclonal antibodies (mAb) formed against CPV and 8 mAb formed against FPV. Each mAb both neutralized and inhibited the hemagglutination of the homologous virus. All mAb tested immunoprecipitated the two capsid proteins. Five mAb were specific for the CPV isolates and one reacted with the FPV, MEV, and RV isolates, but not the CPV. Another mAb reacted only with certain FPV and MEV isolates. The remaining 14 mAb reacted with most parvoviral isolates from the four animal species. Antigenic variation was observed both within and between the parvovirus isolates from each species. The 12 MEV isolates could be grouped into three antigenic types based on their reactivity with the panel of mAb. Antigenic variants of either CPV or FPV were readily selected with several mAb. Analysis of these variant viruses by direct serological tests and competition radioimmune assays between different mAb revealed that the capsid surface contained at least two determinants, each being comprised of many different but overlapping epitopes. 相似文献
24.
25.
A nonhemagglutinating mutant of a 1978 isolate of canine parvovirus (CPV) was derived after repeated passages in the NLFK feline kidney cell line. The mutant CPV was antigenically indistinguishable from wild-type virus when tested with 82 monoclonal antibodies, and it replicated in cat and dog cell lines in culture. Sequences of the VP-1 and VP-2 genes revealed two nucleotide and two predicted amino acid sequence differences at 77 and 88 genome map units in the mutant compared to hemagglutinating viruses. One or both of those two mutations must determine the difference in the ability of the virus to agglutinate erythrocytes. 相似文献
26.
Carolina Tisnado Garland Line Guénette Edeltraut Kröger Pierre-Hugues Carmichael Rachel Rouleau Caroline Sirois 《Journal of the American Medical Directors Association》2021,22(1):141-147
ObjectivesAssess the impact of a new pharmaceutical care model on (1) polypharmacy and (2) potentially inappropriate medication (PIM) use in long-term care facilities (LTCFs).DesignPragmatic quasi-experimental study with a control group. This multifaceted model enables pharmacists and nurses to increase their professional autonomy by enforcing laws designed to expand their scope of practice. It also involves a strategic reorganization of care, interdisciplinary training, and systematic medication reviews.Setting and ParticipantsTwo LTCFs exposed to the model (409 residents) were compared to 2 control LTCFs (282 residents) in Quebec, Canada. All individuals were aged 65 years or older and residing in included LTCFs.MeasuresPolypharmacy (≥10 medications) and PIM (2015 Beers criteria) were analyzed throughout 12 months between March 2017 and June 2018. Groups were compared before and after implementation using repeated measures mixed Poisson or logistic regression models, adjusting for potential confounding variables.ResultsOver 12 months, for regular medications, polypharmacy decreased from 42% to 20% (exposed group) and from 50% to 41% (control group) [difference in differences (DID): 13%, P < .001]. Mean number of PIMs also decreased from 0.79 to 0.56 (exposed group) and from 1.08 to 0.90 (control group) (DID: 0.05, P = .002).Conclusions and ImplicationsCompared with usual care, this multifaceted model reduced the probability of receiving ≥10 medications and the mean number of PIMs. Greater professional autonomy, reorganization of care, training, and medication review can optimize pharmaceutical care. As the role of pharmacists is expanding in many countries, this model shows what could be achieved with increased professional autonomy of pharmacists and nurses in LTCFs. 相似文献
27.
Dellucci Trey V. Carmichael Cheryl Starks Tyrel J. 《Archives of sexual behavior》2021,50(4):1689-1700
Archives of Sexual Behavior - One- to two-thirds of new HIV infections among sexual minority men occur within the context of main partnerships. This has led to increasing attention to the rules and... 相似文献
28.
29.
Mayer-Davis EJ Vitolins MZ Carmichael SL Hemphill S Tsaroucha G Rushing J Levin S 《Annals of epidemiology》1999,9(5):314-324
PURPOSE: There is limited support for the validity and reproducibility of dietary assessment in culturally diverse populations. The goal of this study was to evaluate the comparative validity and reproducibility of a Food Frequency Questionnaire (FFQ) used in the observational, multi-cultural Insulin Resistance Atherosclerosis Study (IRAS). METHODS: Women (n = 186) were approximately equally distributed by ethnicity from one urban center (African Americans and non-Hispanic whites) and one rural center (Hispanics and non-Hispanic whites). The IRAS FFQ was modified from the National Cancer Institute Health Habits and History Questionnaire to include ethnic and regional foods. Validity was assessed by comparing dietary values, including supplements, obtained from the FFQ to the average intake estimated from a series of 8 24-hour dietary recalls collected by telephone over the same 1-year period. Reproducibility was assessed among women who reported no change in their usual diet (n = 133) by comparing data from the original IRAS FFQ (in-person) with the FFQ administered for the validity study (two to four years later, by telephone). RESULTS: Correlation coefficients for validity were statistically significant for most nutrients (mean r = 0.62 urban non-Hispanic white, 0.61 rural non-Hispanic whites, 0.50 African American, 0.41 Hispanic) and did not differ among subgroups of obesity or diabetes status. The median correlation coefficient for the total sample was 0.49. Correlations were lower for women with less than 12 years of education (mean r = 0.30; median r = 0.25). The lower correlations among Hispanics was largely explained by the lower educational attainment in that sample. For reproducibility, the mean correlation for nutrients evaluated was r = 0.62 (median r = 0.63) and did not differ for subgroups. CONCLUSIONS: Although educational attainment must be considered, the IRAS FFQ appears to be reasonably valid and reliable in a diverse cohort. 相似文献
30.
Viollon-Abadie C Lassere D Debruyne E Nicod L Carmichael N Richert L 《Toxicology and applied pharmacology》1999,155(1):1-12
The effects of representative liver enzyme inducers such as clofibrate (CLO), phenobarbital (PB), pregnenolone-16alpha-carbonitrile (PCN), and beta-naphthoflavone (NF) on hepatic microsomal thyroxin (T4)- UDP-glucuronosyl transferase (UGT) and triiodothyronine (T3)- UGT activities and thyroid function were evaluated in OF-1 male mice after a 14-day po administration. CLO, PB, and PCN induced histological liver hypertrophy, increases in liver weights, in microsomal protein and cytochrome P450 contents as well as increases in specific UGT activities. Despite this, no significant changes in T4-UGT and T3-UGT activities occurred after treatment by any of these compounds. Furthermore, no significant changes in serum T4 and T3 levels were observed and thyroid histology was not affected. NF treatment induced microvacuolation of hepatocytes but did not affect any of the other tested parameters. The results show that, in contrast to the widely described effects in rats, liver enzyme inducers do not affect hepatic thyroid hormone metabolism and thyroid function in mice, suggesting that this species should be less sensitive to thyroid tumor promotion by hepatic microsomal enzyme inducers than rats. 相似文献