全文获取类型
收费全文 | 4855篇 |
免费 | 255篇 |
国内免费 | 34篇 |
专业分类
耳鼻咽喉 | 46篇 |
儿科学 | 99篇 |
妇产科学 | 209篇 |
基础医学 | 740篇 |
口腔科学 | 38篇 |
临床医学 | 305篇 |
内科学 | 1233篇 |
皮肤病学 | 159篇 |
神经病学 | 410篇 |
特种医学 | 144篇 |
外科学 | 714篇 |
综合类 | 16篇 |
预防医学 | 217篇 |
眼科学 | 55篇 |
药学 | 224篇 |
中国医学 | 5篇 |
肿瘤学 | 530篇 |
出版年
2023年 | 32篇 |
2022年 | 56篇 |
2021年 | 128篇 |
2020年 | 67篇 |
2019年 | 78篇 |
2018年 | 113篇 |
2017年 | 95篇 |
2016年 | 103篇 |
2015年 | 133篇 |
2014年 | 149篇 |
2013年 | 224篇 |
2012年 | 308篇 |
2011年 | 297篇 |
2010年 | 172篇 |
2009年 | 182篇 |
2008年 | 262篇 |
2007年 | 295篇 |
2006年 | 302篇 |
2005年 | 254篇 |
2004年 | 257篇 |
2003年 | 222篇 |
2002年 | 213篇 |
2001年 | 104篇 |
2000年 | 89篇 |
1999年 | 108篇 |
1998年 | 58篇 |
1997年 | 61篇 |
1996年 | 51篇 |
1995年 | 43篇 |
1994年 | 38篇 |
1993年 | 33篇 |
1992年 | 57篇 |
1991年 | 57篇 |
1990年 | 54篇 |
1989年 | 48篇 |
1988年 | 40篇 |
1987年 | 45篇 |
1986年 | 45篇 |
1985年 | 37篇 |
1984年 | 23篇 |
1983年 | 18篇 |
1982年 | 20篇 |
1981年 | 12篇 |
1979年 | 14篇 |
1978年 | 14篇 |
1977年 | 13篇 |
1974年 | 15篇 |
1972年 | 11篇 |
1969年 | 14篇 |
1968年 | 13篇 |
排序方式: 共有5144条查询结果,搜索用时 15 毫秒
71.
72.
73.
Leptin, the product of the ob gene, is a hormone mainly secreted by the adipose tissue, which acts through specific receptors (Ob-R) widely distributed in the body tissues. Ob-Rs are present in the mammalian hypothalamo-pituitary-adrenal axis, and evidence indicates that leptin regulates adrenocortical secretion. Moreover, leptin is known to act as a growth promoting factor in some tissues, including the endocrine ovary. We have investigated the effects of three subcutaneous injections of 2 nmol/100 g of native murine leptin[1-147] and of its biologically active fragment 116-130 on the secretory and proliferative activity of the regenerating rat adrenal cortex. Leptin[1-147] increased plasma aldosterone concentration at day 8 and plasma corticosterone concentration (PBC) at day 5 of regeneration, without affecting mitotic index. In contrast, leptin[116-130] lowered PBC and mitotic index at both times of adrenal regeneration. In light of the fact that adrenal regeneration is at least in part dependent on the pituitary ACTH, we conclude that: (i) native leptin moderately stimulates steroid secretion, acting directly on the adrenal cortex, through signaling mechanisms other than those involved in the ACTH action; (ii) native leptin is unable to enhance the proliferative activity of regenerating adrenals, which conceivably is maximally stimulated by ACTH; (iii)leptin[1-147] and leptin[116-130] differently interact with Ob-Rs or interact with different receptors; and (iv) leptin[116-130] inhibits the signaling pathways mediating both the secretagogue effect of native leptin and the proliferogenic effect of ACTH. 相似文献
74.
75.
76.
77.
Left ventricular false tendons (or anomalous bands) have been described in several anatomic studies. Recently the echocardiographic features of such false tendons have been reported also. We have found a prevalence of 36 cases in 1,600 consecutive patients examined (2.2%). False tendons represent a rather common and benign phenomenon. Echocardiography is the most useful tool in the detection of false tendons. 相似文献
78.
A. Lonardo P. Loria F. Leonardi A. Borsatti P. Neri M. Pulvirenti A. M. Verrone A. Bagni M. Bertolotti D. Ganazzi N. Carulli POLI.ST.E.N.A. Study Group 《Digestive and liver disease》2002,34(3):204-211
BACKGROUND: Non-alcoholic fatty liver disease is a common reason for hepatological consultation and may herald severe hepatic and extra-hepatic disease. The aetiopathogenesis of this condition is an area of increasing interest. AIM: To evaluate anthropometric and biochemical factors associated to non-alcoholic fatty liver disease in a case-control study. Methods. Demographic and biochemical data of 60 consecutive patients with bright liver absent-to-low alcohol consumption, no evidence of viral, genetic and autoimmune diseases, were compared to those of 60 age- and gender-matched historical controls without fatty liver by univariate and multiple logistic regression analysis. RESULTS: Patients were more often hypertriglyceridaemic, obese and diabetic than controls (p<.01). Mean values of alanine transaminase, gammaglutamyltranspeptidase, triglycerides, uric acid, fasting and log insulin, transferrin percent saturation and ferritin were significantly higher in the patients, while transferrin and quantitative insulin sensitivity check index, a quantitative insulin sensitivity index, were lower. No iron storage was found in those who underwent liver biopsy At univariate analysis the relative risk for non-alcoholic fatty liver disease significantly increased (p<0. 05) with increasing body mass index, fasting insulin, alanine transaminase, uric acid, triglycerides and gammaglutamyltranspeptidase; it decreased with increasing transferrin and quantitative insulin sensitivity check index. Multiple logistic regression analysis disclosed only fasting insulin and uric acid to be independent predictors of non-alcoholic fatty liver disease (p<0.05). CONCLUSIONS: Fasting insulin and serum uric acid levels indicating insulin resistance, but not indices of iron overload, are independent predictors of non-alcoholic fatty liver disease. 相似文献
79.
Coppola L Caserta F Grassia A Mastrolorenzo L Altrui L Tondi G Verde S Coppola A 《Archives of gerontology and geriatrics》2002,35(1):27-34
Urinary incontinence is a common problem in older subjects, very often wrongfully accepted as a normal part of the aging process. A total of 520 subjects (208 males and 312 females; mean age 74.8 +/- 11.8 years), from both private- and nursing-home dwelling populations, were included in this study aimed to estimate the incidence of urinary incontinence and identify factors associated with condition, in aged subjects. The incidence and type of urinary incontinence (stress, urge or mixed incontinence) were assessed by structured questionnaires and diagnosis was confirmed by a seven-day consecutive voiding diary. Assessment of physical, cognitive and emotional functions was performed on each subject using the Mini Mental State Examination (MMSE), Instrumental Activities of Daily Living Scale (IADL), Tinetti Scale (gait), Tinetti Scale (balance) and Geriatric Depression Scale (GDS) instruments. In the total population sample the incidence of urinary incontinence was 47.9%. The incontinence cases were classified, according to the different types, as: stress incontinence (males: 3.4%; females: 8.7%; males+females: 6.5%); urge incontinence (males: 27.4%; females: 31.4%; males+females: 29.8%); mixed incontinence (males: 20.2%; females: 5.8%; males+females: 11.5%). In the total population sample, no significant relationship was found between age and prevalence of urinary incontinence. In the elderly female group, age significantly correlated in a direct manner with urge incontinence (P<0.01) and inversely with stress incontinence (P<0.001). Only in the male sex group age significantly correlated with mixed incontinence (P<0.005). Multiple linear regression analysis showed that the dependent variable 'incontinence' could be predicted by MMSE (P<0.001) in the male sex group and by the Tinetti Scale (gait) (P<0.001) in the female sex group. 相似文献
80.
Reza Ghasemi Antonino Grassadonia Nicola Tinari Enza Piccolo Clara Natoli Federica Tomao Stefano Iacobelli 《Medical hypotheses》2013
Metastasis is the leading cause of cancer death, yet it is mechanistically considered a very inefficient process suggesting the presence of some sort of (e.g. systemic) routes for fuelling the process. The pre-metastatic niche formation is described as one such metastasis promoting route. Now, the emerging potentials of tumor-derived microvesicles (TDMVs), not only in formulating the pre-metastatic niche, but also conferring neoplastic phenotypes onto normal cells, has integrated new concepts into the field. Here, we note as an ancillary proposition that, exerting functional disturbances in other sites, TDMVs (we have termed them metastasomes) may aid foundation of the secondary lesions via two seemingly interrelated models: (i) tumor-organ-training (TOTr), training a proper niche for the growth of the disseminated tumor cells; (ii) tumor-organ-targeting (TOTa), contribution to the propagation of the transformed phenotype via direct or indirect (TOTr-mediated disturbed stroma) transformation and/or heightened growth/survival states of the normal resident cells in the secondary organs. Respecting the high content of the RNA molecules (particularly microRNAs) identified in the secretory MVs, they may play crucial parts in such “malignant trait” spreading system. That is, the interactions between tumor tissue-specific RNA signatures, being transferred via metastasomes, and the cell-type/tissue-specific RNA stockrooms in other areas may settle a unique outcome in each organ. Thus, serving as tumor-organ matchmakers, the RNA molecules may also play substantial roles in the seeding and tropism of the process. 相似文献