全文获取类型
收费全文 | 46777篇 |
免费 | 4952篇 |
国内免费 | 1346篇 |
专业分类
耳鼻咽喉 | 224篇 |
儿科学 | 1158篇 |
妇产科学 | 376篇 |
基础医学 | 15465篇 |
口腔科学 | 541篇 |
临床医学 | 3480篇 |
内科学 | 7760篇 |
皮肤病学 | 1404篇 |
神经病学 | 1674篇 |
特种医学 | 2495篇 |
外国民族医学 | 12篇 |
外科学 | 3102篇 |
综合类 | 5482篇 |
现状与发展 | 14篇 |
预防医学 | 1957篇 |
眼科学 | 346篇 |
药学 | 2813篇 |
10篇 | |
中国医学 | 1337篇 |
肿瘤学 | 3425篇 |
出版年
2024年 | 105篇 |
2023年 | 692篇 |
2022年 | 1217篇 |
2021年 | 1806篇 |
2020年 | 1584篇 |
2019年 | 1849篇 |
2018年 | 1926篇 |
2017年 | 1747篇 |
2016年 | 1670篇 |
2015年 | 1852篇 |
2014年 | 2653篇 |
2013年 | 3056篇 |
2012年 | 2381篇 |
2011年 | 2720篇 |
2010年 | 2175篇 |
2009年 | 2024篇 |
2008年 | 2103篇 |
2007年 | 2033篇 |
2006年 | 1857篇 |
2005年 | 1622篇 |
2004年 | 1584篇 |
2003年 | 1456篇 |
2002年 | 1168篇 |
2001年 | 1088篇 |
2000年 | 936篇 |
1999年 | 840篇 |
1998年 | 897篇 |
1997年 | 836篇 |
1996年 | 738篇 |
1995年 | 756篇 |
1994年 | 771篇 |
1993年 | 666篇 |
1992年 | 416篇 |
1991年 | 338篇 |
1990年 | 347篇 |
1989年 | 269篇 |
1988年 | 224篇 |
1987年 | 165篇 |
1986年 | 146篇 |
1985年 | 358篇 |
1984年 | 373篇 |
1983年 | 239篇 |
1982年 | 294篇 |
1981年 | 243篇 |
1980年 | 184篇 |
1979年 | 174篇 |
1978年 | 111篇 |
1977年 | 101篇 |
1976年 | 115篇 |
1975年 | 68篇 |
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
61.
对28例Graves病的可溶性白介素2受体(sIL2R)和各种甲状腺激素以及甲状腺自身抗体治疗前后比较,并进行逐步回归,结果表明:治疗后Graves病患者除TSH外,各种甲状腺激素及甲状腺自身抗体显著降低(P<001),并对sIL2R的上升与下降呈显著相关。 相似文献
62.
63.
64.
M. M. Moens A. V. Mertens L. S. De Clerck H. P. Van Bever C. H. Bridts W. J. Stevens 《Pediatric allergy and immunology》1993,4(2):89-92
In patients with allergic asthma and rhinitis high numbers of hypodense eosinophils (HE) have been demonstrated. In a previous study we reported that asthmatic and healthy children had more HE than their adult counterparts. We assumed that this might, in part, he due to the presence of immature eosinophils in children. To distinguish between immature and activated eosinophils, determination of eosinophil cationic protein (ECP) might be interesting as it is known that high serum levels of ECP are associated with increased activation of eosinophiis. In this study we determined (he levels of ECP in scrum in asthmatic and healthy children and adults trying to distinguish activated from immature eosinophils. We found that ECP levels were not increased in children (healthy and asthmatic) compared to adults (healthy and asthmatic). This supports the hypothesis that increased numbers of HE in childhood are, at least in part, immature eosinophils. Nevertheless, we could confirm that inflammation was present in children because soluble interleukin-2-receptor (slL-2R), a marker of lymphocyte activation, was higher in asthmatic children as compared to healthy children. IL-6, a marker of macrophage/monocyte activation, was not different in the different patient groups. We conclude that although signs of inflammation are present in childhood asthma, the increased numbers of HE in children are in part due to the presence of immature eosinophils. 相似文献
65.
BACKGROUND: We have previously demonstrated that the proteolytic activity of Der p 1 selectively cleaves human CD25, the 55 kDa alpha subunit of the IL-2 receptor. As a result of cleavage of surface CD25, peripheral blood T cells produce less IFN-gamma and more IL-4, thereby leading to progressive polarization of the T cells towards a Th2 cytokine profile. Therefore, these observations underline the potential role of the proteolytic activity of Der p 1 in creating a microenvironment conducive for IgE synthesis. OBJECTIVE: To study the effect of T cells that have been conditioned by the proteolytic activity of Der p 1 on IgE synthesis by B cells. METHODS: We have examined this concept in experiments whereby T cells that have been exposed to either proteolytically active or inactive Der p 1 were cocultured with autologous B cells and IgE antibody synthesis was monitored. RESULTS: Here we demonstrate for the first time that coculturing T cells that have been in contact with proteolytically active Der p 1 with autologous B cells leads to augmentation of IgE antibody responses. CONCLUSIONS: The proteolytic activity of Der p 1 conditions human T cells, which then become empowered to trigger enhanced IgE synthesis by B cells. 相似文献
66.
M. KROTKIEWSKI L. SJ
STR
M L. SULLIVAN P.-A. LUNDBERG G. LINDSTEDT H. WETTERQVIST P. BJ
RNTORP 《Journal of internal medicine》1984,216(3):269-275
Abstract Thyroid hormones were measured before, during and after acute exercise (60 min) or physical training (3 months) in obese women. Thyroid stimulating hormone concentration increased during acute work and decreased immediately after. No changes were seen during the two following days. An increase was seen after ten days as well as after three months of physical training. Thyroxine concentrations showed no changes. 3,5,3′-Triiodothyronine decreased slightly immediately after acute exercise, and after three months of physical training, 3,3′,5′-triiodothyronine (reverse triiodothyronine) increased slowly during and after acute exercise. A negative correlation was found between changes in fasting insulin and thyroxine and a positive correlation between changes in blood pressure and triiodothyronine after training. Lack of agreement in previous reports is probably due to methodological differences such as methods more or less susceptible to fatty acid interference, and thyroid hormones changing differently during acute work and before and after physical training. The duration of the study may also be of importance, even 3 months possibly being too short for attaining equilibrium in thyroid homeostasis. 相似文献
67.
Manjula K. Gupta Karen Seifarth Sharad D. Deodhar O. P. Schumacher 《Journal of clinical laboratory analysis》1987,1(1):124-128
A sensitive, simultaneous sandwich enzyme immunoassay for TSH was evaluated especially for its ability to distinguish hyperthyroid patients from the euthyroid population. A total of 140 patient samples was analzyed by this assay as well as with a two-step sandwich radioimmunoassay. The diagnostic sensitivity of the thyrotropin assay was 92.5% and the specificity was 88%. False negatives by thyrotropin assay included two patients with Graves' disease who were being treated with propranolol at the time of testing and one patient who was considered hyperthyroid while receiving synthroid. Twelve patients with elevated free thyroxine index levels were considered euthyroid and 50% of these had thyrotropin values that were undetectable; most were elderly patients with nonthyroidal illnesses. Although the thyrotropin enzyme immunoassay had good sensitivity and precision for the detection of hyperthyroidism, our data suggest the limitation of a single thyrotropin determination in establishing the euthyroid state, especially in elderly patients with associated nonthyroidal illnesses and hyperthyroxinemia. 相似文献
68.
Katherine Wiegmann Shylaja Muthyala Duk Hwan Kim Barry G. W. Arnason Ewa Chelmicka-Schorr 《Journal of neuroimmunology》1995,56(2)
Chronic/relapsing experimental allergic encephalomyelitis (CREAE) serves as an animal model for relapsing/remitting multiple sclerosis. Treatment with the β-adrenergic agonist isoproterenol or the β2-adrenergic agonist terbutaline significantly suppressed both the first acute attack and the number of relapses in CREAE Lewis rats. The number of relapses was decreased even when treatment with β-adrenergic agonist was started after the onset of the first acute attack of CREAE. β-adrenergic receptor number was increased significantly on splenocytes from CREAE rats as compared to healthy controls or CFA-injected rats. Terbutaline treatment of CREAE rats lowered the splenocyte receptor number to normal values. 相似文献
69.
Peripheral blood CD3 and CD4 T-lymphocyte reduction correlates with severity of liver cirrhosis 总被引:2,自引:0,他引:2
L. Lombardo A. Capaldi G. Poccardi P. Vineis 《International Journal of Clinical & Laboratory Research》1995,25(3):153-156
Summary Immunological disturbances with impairment of immune function and a higher incidence of lymphoproliferative disorders and
other malignancies have been described in liver cirrhosis patients. To investigate the pathogenetic mechanism(s) involved
in such associated we looked for a possible imbalance in peripheral blood T-lymphocyte subpopulations in patients with liver
cirrhosis of differing severity. Immunophenotyping and counts of peripheral blood T-lymphocyte subpopulations were carried
out using monoclonal antibodies conjugated with different fluorochromes in 31 consecutive cirrhotic patients and 23 matched
healthy volunteers. Univariate and multivariate analyses of lymphocyte phenotype counts were performed and odds ratios were
computed. Statistically significant associations, according to both univariate and multivariate analyses, were found between
case/control status and mean CD3 and CD4 T-lymphocyte counts (P<0.0001). A strong correlation was found between the Pugh’s index and CD3 and CD4 lymphocyte counts, with a clear reduction
of these phenotypes with increasing liver cirrhosis. Median CD3 and CD4 values were 2,283 and 1,329/μl respectively among
controls and 896, 801, and 492/μl and 515, 514, and 307/μl, respectively in categories A, B, and C of Pugh’s classification.
Very high odds ratios were found using the median values of CD3 and CD4 as a threshold. There was a statistically significant
decrease for each of the T-cell phenotypes studied (CD2, CD3, CD4, CD8, CD16, CD19, CD20, CD56, CD57) between patients and
controls (P<0.0001). The progressive and severity-related decrease in mean peripheral blood CD3 and CD4 counts in liver cirrhosis suggests
a progressive impairment of protective immune function and may be a factor facilitating malignancy in cirrhotic patients. 相似文献
70.
Demetrius Moskophidis Elisabeth Laine Rolf M. Zinkernagel 《European journal of immunology》1993,23(12):3306-3311
Antiviral cytotoxic memory CD8+ T cells adoptively transferred to mice which are persistently infected with lymphocytic choriomeningitis virus WE or DOCILE initially proliferated extensively; they either caused the death of the recipient or, alternatively, disappeared within a few days. Apparently, the complete and coordinated induction and stimulation by widely distributed viral antigen caused these memory T cells to die before virus had been eliminated from the host. Thus memory T cells are as susceptible to peripheral exhaustion/deletion as unprimed T cells. These results indicate possible limitations of exclusively CD8+ T cell-mediated adoptive immunotherapy against viral infections or tumors. 相似文献