全文获取类型
收费全文 | 1829篇 |
免费 | 137篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 32篇 |
儿科学 | 57篇 |
妇产科学 | 42篇 |
基础医学 | 202篇 |
口腔科学 | 23篇 |
临床医学 | 132篇 |
内科学 | 321篇 |
皮肤病学 | 29篇 |
神经病学 | 140篇 |
特种医学 | 56篇 |
外科学 | 278篇 |
综合类 | 21篇 |
一般理论 | 1篇 |
预防医学 | 169篇 |
眼科学 | 91篇 |
药学 | 102篇 |
中国医学 | 13篇 |
肿瘤学 | 262篇 |
出版年
2023年 | 23篇 |
2022年 | 50篇 |
2021年 | 100篇 |
2020年 | 60篇 |
2019年 | 79篇 |
2018年 | 97篇 |
2017年 | 58篇 |
2016年 | 93篇 |
2015年 | 61篇 |
2014年 | 76篇 |
2013年 | 91篇 |
2012年 | 164篇 |
2011年 | 164篇 |
2010年 | 69篇 |
2009年 | 69篇 |
2008年 | 96篇 |
2007年 | 97篇 |
2006年 | 90篇 |
2005年 | 68篇 |
2004年 | 62篇 |
2003年 | 54篇 |
2002年 | 56篇 |
2001年 | 20篇 |
2000年 | 31篇 |
1999年 | 23篇 |
1998年 | 7篇 |
1997年 | 3篇 |
1996年 | 7篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 9篇 |
1991年 | 7篇 |
1990年 | 5篇 |
1989年 | 9篇 |
1988年 | 8篇 |
1987年 | 4篇 |
1985年 | 2篇 |
1979年 | 3篇 |
1976年 | 5篇 |
1975年 | 9篇 |
1974年 | 5篇 |
1972年 | 7篇 |
1971年 | 3篇 |
1967年 | 2篇 |
1966年 | 4篇 |
1956年 | 1篇 |
1947年 | 1篇 |
1946年 | 1篇 |
1939年 | 1篇 |
排序方式: 共有1971条查询结果,搜索用时 31 毫秒
1.
The relationship between methylxanthine intake (caffeine, theobromine and theophylline) and risk of benign proliferative epithelial disorders (BPED) of the breast was examined in a case-control study conducted in Adelaide, South Australia. The study involved 383 cases with biopsy-confirmed BPED, 192 controls whose biopsy did not show epithelial proliferation, and 383 unbiopsied community controls individually matched to cases on age and area of residence. Overall, there was relatively little variation in risk of BPED with total methylxanthine intake, or with intake of caffeine or theophylline, while there was a positive association between theobromine intake and risk of BPED, but only when cases were compared with biopsy controls. Total methylxanthine intake was positively associated with risk of BPED showing severe atypia, but the trend in risk was statistically significant only when community controls formed the comparison group. These data do not provide strong support for an association between methylxanthine intake and risk of BPED. 相似文献
2.
3.
Current models hold that CD4+ depletion occurs as a result of direct and indirect effects of HIV, which both kill peripheral
CD4+ cells and prevent adequate regeneration. Although age-associated involution diminishes thymic reserve and HIV is clearly
thymotoxic, clinical trials have nonetheless shown that large proportions of patients who sustain adequate control of viral
replication with highly active antiretroviral therapy (HAART) will demonstrate some evidence for thymic-dependent immune reconstitution,
which is associated with improved immune competence. Furthermore, patients with insufficient or absent immune reconstitution
following HAART generally lack evidence for thymopoiesis. Current studies are focused on improving our understanding of the
causes for thymic failure in HIV infection. Recent work has demonstrated that some HIV strains, especially those that are
CXCR4 trophic, are more thymotoxic and may contribute to irreversible thymic damage in this population. 相似文献
4.
Current models hold that CD4+ depletion occurs as a result of direct and indirect effects of HIV, which both kill peripheral CD4+ cells and prevent adequate regeneration. Although age-associated involution diminishes thymic reserve and HIV is clearly thymotoxic, clinical trials have nonetheless shown that large proportions of patients who sustain adequate control of viral replication with highly active antiretroviral therapy (HAART) will demonstrate some evidence for thymic-dependent immune reconstitution, which is associated with improved immune competence. Furthermore, patients with insufficient or absent immune reconstitution following HAART generally lack evidence for thymopoiesis. Current studies are focused on improving our understanding of the causes for thymic failure in HIV infection. Recent work has demonstrated that some HIV strains, especially those that are CXCR4 trophic, are more thymotoxic and may contribute to irreversible thymic damage in this population. 相似文献
5.
The Mouse Secretome: Functional Classification of the Proteins Secreted Into the Extracellular Environment 总被引:1,自引:0,他引:1
下载免费PDF全文
![点击此处可从《Genome research》网站下载免费的PDF全文](/ch/ext_images/free.gif)
6.
Humphrey RK Beattie GM Lopez AD Bucay N King CC Firpo MT Rose-John S Hayek A 《Stem cells (Dayton, Ohio)》2004,22(4):522-530
7.
Repertoire of transcribed peripheral blood T-cell receptor beta chain variable-region genes in acute rheumatic fever.
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
W G Abbott M A Skinner L Voss D Lennon P L Tan J D Fraser I J Simpson R Ameratunga A Geursen 《Infection and immunity》1996,64(7):2842-2845
Patients with severe group A streptococcal infections have abnormalities in the Vbeta repertoire of peripheral blood T cells that are consistent with superantigen stimulation by cytoplasmic membrane proteins. The purpose of this study was to determine whether similar changes in Vbeta repertoire could be found for patients with acute rheumatic fever (ARF). The mean Vbeta repertoire of peripheral blood T cells in nine hospitalized ARF patients was similar to that of 34 controls and did not change during 6 months of follow-up in 6 of the ARF subjects. We were unable to detect changes in the Vbeta repertoire of peripheral blood T cells from patients with ARF that could be attributed to the influence of a superantigen. 相似文献
8.
Rohan LC Edwards RP Kelly LA Colenello KA Bowman FP Crowley-Nowick PA 《Clinical and diagnostic laboratory immunology》2000,7(1):45-48
Measurement of immune components in mucosal secretions is important for the evaluation of local immunity at the mucosal surfaces. The Weck-Cel ophthalmic sponge provides a method for the collection of these secretions. The sponge absorbs a relatively large volume of material, therefore allowing for quantitation of multiple immune components. Additionally, it provides a method in which the same device may be used to collect specimens from different mucosal sites, such as the genital tract and oral cavity. This sampling technique has successfully been applied for collection and measurement of antibody in oral and genital tract secretions. The purpose of this work was to optimize the extraction of protein from the sponge matrix. Of particular interest was the recovery of cytokines from the sponge. Satisfactory recovery of the cytokines interleukin 1beta (IL-1beta), IL-2, IL-5, IL-12, IL-6, IL-8, IL-10, and granulocyte-macrophage colony-stimulating factor was obtained. However, IL-4 and gamma interferon recovery rates remained low. Using an alteration of the published extraction method, cytokine concentrations were measured in cervical secretions from women using oral contraceptives. The data revealed detectable concentrations of IL-6, IL-10, IL-8, and IL-12 on cycle days 9 and 20. The proposed technique provides an easy, practical, and consistent method for collection of nonconventional body fluids, such as cervicovaginal fluids and saliva, for the assay of immunoglobulins and several cytokines. 相似文献
9.
Lai M Wang F Rohan JG Maeno-Hikichi Y Chen Y Zhou Y Gao G Sather WA Zhang JF 《Nature neuroscience》2005,8(4):435-442
Voltage-gated Ca(2+) channels (VGCCs) are important in regulating a variety of cellular functions in neurons. It remains poorly understood how VGCCs with different functions are sorted within neurons. Here we show that the t-complex testis-expressed 1 (tctex1) protein, a light-chain subunit of the dynein motor complex, interacts directly and selectively with N- and P/Q-type Ca(2+) channels, but not L-type Ca(2+) channels. The interaction is insensitive to Ca(2+). Overexpression in hippocampal neurons of a channel fragment containing the binding domain for tctex1 significantly decreases the surface expression of endogenous N- and P/Q-type Ca(2+) channels but not L-type Ca(2+) channels, as determined by immunostaining. Furthermore, disruption of the tctex1-Ca(2+) channel interaction significantly reduces the Ca(2+) current density in hippocampal neurons. These results underscore the importance of the specific tctex1-channel interaction in determining sorting and trafficking of neuronal Ca(2+) channels with different functionalities. 相似文献
10.
Adrian Trenholme Rachel Webb Shirley Lawrence Sharon Arrol Susan Taylor Shanthi Ameratunga Catherine A. Byrnes 《Emerging infectious diseases》2021,27(2):641
In March 2020, a national elimination strategy for coronavirus disease was introduced in New Zealand. Since then, hospitalizations for lower respiratory tract infection among infants <2 years of age and cases of respiratory syncytial or influenza virus infection have dramatically decreased. These findings indicate additional benefits of coronavirus disease control strategies. 相似文献