全文获取类型
收费全文 | 9159篇 |
免费 | 666篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 52篇 |
儿科学 | 264篇 |
妇产科学 | 242篇 |
基础医学 | 1041篇 |
口腔科学 | 409篇 |
临床医学 | 1008篇 |
内科学 | 1683篇 |
皮肤病学 | 94篇 |
神经病学 | 832篇 |
特种医学 | 459篇 |
外科学 | 1259篇 |
综合类 | 403篇 |
一般理论 | 11篇 |
预防医学 | 955篇 |
眼科学 | 175篇 |
药学 | 449篇 |
中国医学 | 5篇 |
肿瘤学 | 495篇 |
出版年
2022年 | 53篇 |
2021年 | 138篇 |
2020年 | 69篇 |
2019年 | 127篇 |
2018年 | 150篇 |
2017年 | 120篇 |
2016年 | 131篇 |
2015年 | 142篇 |
2014年 | 193篇 |
2013年 | 312篇 |
2012年 | 418篇 |
2011年 | 446篇 |
2010年 | 249篇 |
2009年 | 226篇 |
2008年 | 387篇 |
2007年 | 420篇 |
2006年 | 395篇 |
2005年 | 391篇 |
2004年 | 388篇 |
2003年 | 354篇 |
2002年 | 370篇 |
2001年 | 300篇 |
2000年 | 289篇 |
1999年 | 264篇 |
1998年 | 120篇 |
1997年 | 95篇 |
1996年 | 85篇 |
1995年 | 75篇 |
1994年 | 86篇 |
1993年 | 79篇 |
1992年 | 223篇 |
1991年 | 217篇 |
1990年 | 231篇 |
1989年 | 192篇 |
1988年 | 209篇 |
1987年 | 210篇 |
1986年 | 189篇 |
1985年 | 191篇 |
1984年 | 97篇 |
1983年 | 100篇 |
1982年 | 72篇 |
1981年 | 66篇 |
1980年 | 59篇 |
1979年 | 84篇 |
1978年 | 84篇 |
1977年 | 55篇 |
1974年 | 60篇 |
1972年 | 59篇 |
1971年 | 65篇 |
1970年 | 49篇 |
排序方式: 共有9836条查询结果,搜索用时 15 毫秒
91.
Cervical smear results reporting the presence of inflammation are regularly encountered by smeartakers, yet the significance of this finding is not clear. We wished to evaluate whether the presence of inflammation on smear test was associated with a higher incidence of lower genital tract infection. A retrospective review was carried out on women attending our colposcopy unit for their first visit during 2001. Results of 256 women were available for analysis. Evidence of inflammation was found in 9.7% of smears. Genital tract infection was found in 29.2% of women overall. Infection with more than one micro-organism was present in 8.9 percent. Forty eight percent of women having inflammatory changes on smear test had genital tract infection. This compared with 27.3% of women whose smear tests showed no evidence of inflammation. Prevalence of infection with Chlamydia trachomatis, Candida, Bacteroides and Gardnerella vaginalis was higher in the inflammatory smear group. This study shows that women with an inflammatory smear are more likely to harbour genital tract infection than women whose smear shows no evidence of inflammation. Chlamydia infection in particular has long-term fertility consequences through its potential to cause asymptomatic tubal damage: it was present in a substantial proportion of women with inflammation on smear (20%). Screening for lower genital tract infection via high vaginal swab and either intracervical swab or urinary screening for Chlamydia infection should be carried out in all women with smear tests reporting the presence of inflammation. 相似文献
92.
Ciancio G Burke GW Roth D Miller J 《BioDrugs : clinical immunotherapeutics, biopharmaceuticals and gene therapy》1999,11(6):395-407
Immunosuppression, although necessary to enable the graft to escape the consequences of immune surveillance, carries some risks for the patient. There is an associated increase in neoplasms, opportunistic infections and end-organ toxicity. In addition, even with excellent patient compliance, rejection (acute and chronic) remains a major limitation that contributes to the loss or decrease in the function of the allograft. New drugs have been added to the armamentarium of immunosuppressive agents to suppress allograft rejection and to rescue grafts from cyclosporin-resistant rejection. With the availability of these immunosuppressive agents, it has become increasingly difficult to choose the appropriate combination of immunosuppressants with a beneficial effect for the patient and for the allograft. We describe 2 new immunosuppressive agents and some of their different uses in solid organ transplantation. 相似文献
93.
1. The responses of 62 putative muscle spindle afferents innervating the pretibial flexor muscles of normal human subjects were studied during graded twitch contractions of the receptor-bearing muscle to search for possible in-series coupling between spindle endings and motor units. 2. The majority of afferents (n = 57) responded unequivocally in an in-parallel manner to the twitch contractions, regardless of contraction strength. There were two patterns of in-parallel response: afferents without background activity discharged during the relaxation phase of the twitch; afferents with a background discharge were transiently silenced during the contraction phase and resumed their discharge on the relaxation phase. 3. Evidence of in-series coupling was found for five afferents during submaximal twitch contractions, to which each afferent responded in a mixed "biphasic" manner, with increases in discharge during both the contraction and relaxation phases of the twitch. Background discharge, response to stretch, and response during isometric voluntary contractions suggested that four of the afferents innervated primary spindle endings and the fifth a secondary spindle ending. 4. It is argued that the five atypical spindle endings responded in an ambiguous manner during twitch contractions of the receptor-bearing muscle because there was an in-series mechanical coupling between motor units and the spindle. The incidence of demonstrable in-series responses has serious implications for the mechanisms of spindle activation during normal motor behavior, but has only minor implications for the use of the twitch test to identify muscle spindle endings. 相似文献
94.
Luis F Gonzalez-Cuyar Dora Lam-Himlin Fabio Tavora Allen Burke Rudy J Castellani 《Cardiovascular pathology》2008,17(2):113-116
BACKGROUND: Bilateral internal carotid artery agenesis (ICAA) is a rare developmental anomaly of unknown etiology that is often associated with disruption of adequate perfusion to the central nervous system. Nevertheless, some patients remain asymptomatic due to collateral circulation involving the communicating arteries of the Circle of Willis. Secondary to the hemodynamical stress through the collateral circulation, affected patients are at an increased risk of developing subarachnoid hemorrhage and intracranial aneurysms. METHODS AND RESULTS: We report an unusual case of a 62-year-old man with bilateral ICAA who expired following two asystolic events during minor surgery. CONCLUSION: This case emphasizes the plasticity of the cerebral collateral circulation during development, to the point of normal cerebral perfusion throughout life with no ischemic complications. 相似文献
95.
Michael A Burke Dorothy Hutter Rita P Reshamwala Janice E Knepper 《Developmental dynamics》2003,227(3):315-322
Involution of the mammary gland after weaning occurs in two stages. The first stage is reversible, whereas the second stage is characterized by the irreversible collapse of the alveolar structure. A differential display analysis using cDNAs from tissues obtained at various times after forced weaning of pups identified cathepsin L as up-regulated during early involution. Levels of cathepsin L mRNA were dramatically increased within 24 hr after weaning. Cathepsin L protein detected by immunoblot was also increased during involution, reaching near maximal levels by 36 hr after weaning. In situ immunohistochemistry detected pronounced cathepsin L protein in the cytoplasm and cell periphery. Mice treated with a specific inhibitor of cathepsin L exhibited substantially reduced numbers of apoptotic cells at times up to 72 hr after weaning when compared with untreated animals. The cathepsin L inhibitor did not alter levels of cathepsin L detected in immunoblots or influence molecular weight of the cathepsin L species detected. These data suggest that cathepsin L plays a regulatory role early in the process of mammary gland involution. 相似文献
96.
Cook JA Cohen MH Burke J Grey D Anastos K Kirstein L Palacio H Richardson J Wilson T Young M 《Journal of acquired immune deficiency syndromes (1999)》2002,30(4):401-409
This study examines the effects of depressive symptoms and mental health quality of life on utilization of highly active antiretroviral therapy (HAART) among HIV-seropositive women. Data were collected biannually from 1996 through 1998 in a prospective cohort study. Women reported use of antiretroviral therapy, health and mental health status, demographics, and social and behavioral factors; CD4 count and viral load also were assessed. Random effects regression models estimated the longitudinal effects of depressive symptoms and mental health quality of life on the probability of HAART utilization, controlling for clinical indicators (CD4 count, viral load, symptom presence), demographics (race, age, education), behavioral factors (drug/alcohol use, clinical trials participation), service features (insurance status, mental health service utilization), and study site. High levels of depressive symptoms and poor mental health quality of life were found, and they significantly reduced the probability of HAART utilization. Receiving mental health services significantly increased the probability of utilizing HAART. HIV-seropositive women characterized as being in poor mental health were less likely to use HAART, whereas those receiving treatment of mental health difficulties were more likely to use HAART. These findings suggest that efforts to enhance women's access to psychological treatment may increase their use of the latest HIV therapies. 相似文献
97.
Anti-heart antibodies in postpericardiotomy syndrome: cause or epiphenomenon? A prospective,longitudinal pilot study 总被引:3,自引:0,他引:3
OBJECTIVES: To assess the role of anti-heart antibodies (AHA) in postpericardiotomy syndrome (PPS) and the timing of their appearance in relation to the initial manifestations of PPS. DESIGN AND SUBJECTS: Twenty patients who were scheduled to undergo elective coronary artery bypass grafting (CABG) were enrolled in a prospective, longitudinal pilot study. METHODS: Serum was sampled for AHA on the day prior to surgery and at regular intervalsfollowing surgery in all patients. In those who developed PPS, the serum AHA was determined on the day that typical clinical manifestations of PPS appeared and at regular intervals following the onset of PPS. RESULTS: All patients were negative for AHA on the day precedingsurgery. Three(15%) patients developed PPS. Their sera were negative for AHA on the day they were diagnosed as sufferingfrom PPS and the sera became positive for AHA within 14 days from the time of diagnosis. The intensity of immunofluorescence decreased markedly 30 days afterwards and AHA had disappeared within 90days after diagnosis of PPS. The other 17 (85%) patients were negative for AHA prior to surgery and remained so during the six-month postoperative follow-up period. CONCLUSION: The findings of this study suggest that serum AHA may not play a causal role inthe pathogenesis of PPS, but may rather be an epiphenomenon, reflecting an immune response to pericardial and/or myocardial injury. 相似文献
98.
A Meager H E Graves J R Walker D C Burke D M Swallow A Westerveld 《The Journal of general virology》1979,45(2):309-321
Forty-two primary human-mouse cell hybrids, derived in two separate experiments, were treated with Newcastle disease virus (NDV): eight hybrids were found to produce human interferon and this was shown in every case to be predominantly of the fibroblast type. An extensive analysis was made in terms of karyotype and marker enzymes on all the eight hybrids producing interferon and also on five hybrids which did not produce interferon, five randomly selected hybrids and eleven subclones resistant to diphtheria toxin. The results suggest that, contrary to previous reports, a gene on chromosome 5 is not involved in production of human interferon. Its production was however correlated with the presence of chromosome 9 in the hybrids. Analyses of two sets of human-Chinese hamster hybrid subclones from two different crosses were also consistent with the assignment of a human interferon gene to chromosome 9. 相似文献
99.
G B Stickler M H Shin E C Burke K E Holley R H Miller W E Segar 《The New England journal of medicine》1968,279(20):1077-1082
100.
To see whether genetic polymorphisms regulate inter-individual differences in T cell subset levels, we have conducted a genome scan in two populations of mice, bred as the progeny of a cross between CB6F1 females and C3D2F1 males. The data document quantitative trait loci (QTL) with statistically significant effects on CD4, CD8, and CD8 memory T cells, and on subsets of CD4 and CD8 T cells that express P-glycoprotein. Some of the loci detected were robust, in the sense that they produced effects of similar size both in mated female mice, and in a population that included male and female virgin animals. Some of the effects were stable, in that they were apparent at both 8 and 18 months of age, but others were age-specific, showing effects either at 8 or at 18 months but not at both ages. Genes that had an effect on the same T cell subset were in almost all cases additive rather than epistatic, and their combined effects could produce large overall effects, leading in the most dramatic case to a two-fold difference in CD8 memory cells. The analysis also documented two QTL, on chromosomes 4 and 13, that regulate an age-sensitive composite index of T cell subset pattern which has been shown previously to be a predictor of life expectancy in these mice. The analysis thus reveals both subset-specific genes and others which modulate the overall pattern of age-sensitive changes in T cell subset distributions. 相似文献