全文获取类型
收费全文 | 5857篇 |
免费 | 296篇 |
国内免费 | 18篇 |
专业分类
耳鼻咽喉 | 102篇 |
儿科学 | 190篇 |
妇产科学 | 251篇 |
基础医学 | 777篇 |
口腔科学 | 241篇 |
临床医学 | 465篇 |
内科学 | 1012篇 |
皮肤病学 | 94篇 |
神经病学 | 477篇 |
特种医学 | 239篇 |
外科学 | 856篇 |
综合类 | 53篇 |
一般理论 | 2篇 |
预防医学 | 392篇 |
眼科学 | 196篇 |
药学 | 329篇 |
中国医学 | 7篇 |
肿瘤学 | 488篇 |
出版年
2023年 | 40篇 |
2022年 | 73篇 |
2021年 | 126篇 |
2020年 | 100篇 |
2019年 | 128篇 |
2018年 | 145篇 |
2017年 | 96篇 |
2016年 | 169篇 |
2015年 | 162篇 |
2014年 | 190篇 |
2013年 | 278篇 |
2012年 | 374篇 |
2011年 | 358篇 |
2010年 | 212篇 |
2009年 | 199篇 |
2008年 | 376篇 |
2007年 | 353篇 |
2006年 | 374篇 |
2005年 | 323篇 |
2004年 | 294篇 |
2003年 | 276篇 |
2002年 | 260篇 |
2001年 | 85篇 |
2000年 | 80篇 |
1999年 | 104篇 |
1998年 | 82篇 |
1997年 | 62篇 |
1996年 | 55篇 |
1995年 | 40篇 |
1994年 | 50篇 |
1993年 | 68篇 |
1992年 | 48篇 |
1991年 | 51篇 |
1990年 | 44篇 |
1989年 | 53篇 |
1988年 | 34篇 |
1987年 | 27篇 |
1986年 | 28篇 |
1985年 | 37篇 |
1984年 | 21篇 |
1983年 | 23篇 |
1982年 | 21篇 |
1981年 | 23篇 |
1980年 | 13篇 |
1979年 | 33篇 |
1978年 | 20篇 |
1977年 | 13篇 |
1974年 | 17篇 |
1973年 | 13篇 |
1972年 | 18篇 |
排序方式: 共有6171条查询结果,搜索用时 15 毫秒
11.
Exclusive expression of MHC class II proteins on CD45+ cells in pancreatic islets of NOD mice. 总被引:6,自引:0,他引:6
The expression of MHC class II molecules on beta-cells of the pancreatic islet has been proposed to play a role in the genesis of insulin-dependent diabetes mellitus in the NOD mouse. We investigated this by immunofluorescent double labeling of islet cells with anti-MHC and anti-CD45 to identify cells of hematopoietic origin. MHC class I expression increased with age on CD45- islet cells. MHC class II expression was not observed on CD45- islet cells at any age; the only cells in the islet that were MHC class II positive were also CD45+. This indicates that all MHC class II-positive cells in the islet are lymphoid cells that infiltrate the islet, whereas the islet endocrine cells express no MHC class II molecules. However, an increase in MHC class I expression occurred on beta-cells, and this may play a role in immunopathogenesis. 相似文献
12.
P-fimbriae vaccines 总被引:3,自引:0,他引:3
M. Bernice Kaack Auli Pere Timo K. Korhonen Stefan B. Svenson James A. Roberts 《Pediatric nephrology (Berlin, Germany)》1989,3(4):386-390
To test for cross-protective capacity of two different P-fimbriae vaccines we vaccinated baboons with fimbriae purified from either Escherichia coli strain ER2 or strain JR1. The vaccinated animals showed elevated antibody titers to P-fimbriae from each of the E. coli strains used, suggesting cross-reactivity as was expected from the results of immunoprecipitation of the fimbriae. Enzyme-linked immunosorbent assay inhibition by heterologous P-fimbriae proved this to be true immunologic cross-reactivity. 相似文献
13.
Pekka Jousilahti Veikko Salomaa Katri Hakala Vesa Rasi Elina Vahtera Timo Palosuo 《Annals of allergy, asthma & immunology》2002,89(4):381-385
BACKGROUND: Airway inflammation is a characteristic feature of bronchial asthma. Previous studies have shown an increased local inflammatory activity in the airway mucosa of asthma patients. OBJECTIVES: To analyze the association of asthma with three sensitive markers of systemic inflammation, C-reactive protein, serum amyloid-A (SAA), and plasma fibrinogen. METHODS: A cross-sectional, population-based study including 1,513 Finnish men aged 45 to 74 years, who participated in a chronic disease risk factor survey in 1997. Of the participating men, 97 were classified as asthma patients. The odds ratios of asthma were analyzed by quartile of each inflammation marker. RESULTS: In logistic regression models the age-adjusted odds ratios (second, third, and fourth quartile as compared with the first quartile) of asthma increased gradually with increasing quartile of C-reactive protein (1.28, 1.19, 1.96, P for trend = 0.039), SAA (1.20, 3.00, 3.49, P for trend < 0.001), and fibrinogen (1.22, 1.79, 3.16, P for trend < 0.001). The associations were independent of smoking. Further adjustment for waist-to-hip ratio, a marker of central obesity, and symptoms of chronic bronchitis weakened the observed association, but the increasing trend in the association of SAA and fibrinogen with asthma remained highly significant. CONCLUSIONS: Sensitive markers of systemic inflammation, particularly SAA and fibrinogen, were positively and significantly associated with asthma prevalence. These findings support the hypothesis that not only local, but also systemic, inflammation exist in bronchial asthma. 相似文献
14.
Timo Laatikainen Henri Kurunmäki Aarne Koskimies 《Journal of assisted reproduction and genetics》1988,5(1):14-17
Of 70 cycles stimulated with clomiphene and human menopausal gonadotropin (hMG) for an in vitro fertilization-embryo transfer (IVF-ET) program, a short luteal phase of 11 days or less was found in 18. In this group the mean estradiol and progesterone levels were elevated in the early luteal phase. Despite the elevated initial values, progesterone levels fell rapidly at the mid luteal phase as a sign of premature luteolysis. The mean total amount of gonadotropin administered and the mean number of follicles punctured and of oocytes recovered did not show any significant difference between the groups of normal and short luteal phases. The present findings support the theory that hyperestrogenism in the early luteal phase may initiate the premature luteolysis observed in clomiphene-menopausal gonadotropin-stimulated cycles. 相似文献
15.
16.
17.
Depression-executive dysfunction syndrome in stroke patients. 总被引:6,自引:0,他引:6
Risto Vataja Tarja Pohjasvaara Riitta M?ntyl? Raija Ylikoski Maarit Leskel? Hely Kalska Marja Hietanen Hannu Juhani Aronen Oili Salonen Markku Kaste Antero Lepp?vuori Timo Erkinjuntti 《The American journal of geriatric psychiatry》2005,13(2):99-107
OBJECTIVE: It has been suggested that executive dysfunction could be the core defect in patients with geriatric or vascular depression, and that this depression-dysexecutive syndrome (DES) might be related to frontal-subcortical circuit dysfunction. The authors tested this hypothesis in 158 poststroke patients, of whom 21 had both depression and executive dysfunction. Methods: In this cross-sectional cohort study, a neurological, psychiatric, and neuropsychological examination was carried out 3 months after ischemic stroke, and brain infarcts, white-matter changes, and brain atrophy were recorded by MRI. RESULTS: The 21 patients with DES had significantly more brain infarcts affecting their frontal-subcortical circuit structures than the 137 patients without DES, or the 41 patients with depression but without executive dysfunction. Patients with DES also had more severe depressive symptoms and worse psychosocial functioning, and they coped less well in complex activities of daily living. CONCLUSIONS: DES is a valid concept and may define a subgroup of poststroke patients with frontal-subcortical pathology and with distinct prognosis and treatment options. 相似文献
18.
Primary breast lymphoma. 总被引:2,自引:0,他引:2
Primary breast lymphoma (PBL) is a rare tumor of the breast. Three cases of PBL are being described. All three cases achieved remission following biopsy, chemotherapy, and/or radiotherapy. The literature is extensively reviewed with emphasis on true incidence of PBL and survival rates. 相似文献
19.
Anita Kumari Muni Arundhati Rath Aparajita Choudhury 《Early child development and care》1997,132(1):105-114
Family resources in terms of their qualitative (process) and quantitative (structure) nature influences the development of social competence in children/adolescents. Present study aims at exploring the relationship of family resource variables with three measures of social competence of 300 adolescent belonging to different socio-cultural status. Socio-culturally advantaged group samples were found to have healthy family environment, whereas, socio-culturally disadvantaged group perceived themselves as at disadvantages and were deprived in seeking positive intra-family support. However inspite of their disadvantages, they were found to be more self-competent. On the other hand, advantaged group adolescents were found to be more competent in the areas of peer and teacher related social competence. Product-moment coefficient correlation analysis revealed that parental education, occupation and family income were found to be significantly associated with positive peer and teacher related social competence in case of the samples belonging to the advantaged socio-cultural group. However, negative responses and outside family support was found to be positively associated with the development of disadvantaged group adolescent's self-related competence. In general, present study supports the hypothesis that Indian family system still continues to be considered as the major source of support for the adolescents, in spite of their growing tendency for independence, self-definition and autonomy. 相似文献
20.
V. Ramesh G. K. Rath S. Chandar S. Bahadur 《Indian journal of otolaryngology and head and neck surgery》1993,45(3):154-155
A sixty year old patient underwent radical Radiotherapy for a transglottic laryngeal carcinoma and the primary site was free of disease 6 weeks later. The initial work up showed a clear roentgenogram of the chest and the vertebral architecture was normal. The patient had neurological symptoms few months later and a diagnostic CT Scan of brain showed intracranial metastases. Locally he was disease free as in the chest. After a palliative course of radiotherapy of the brain, the patient expired. The probable route of spread was discussed. 相似文献