全文获取类型
收费全文 | 15014篇 |
免费 | 838篇 |
国内免费 | 145篇 |
专业分类
耳鼻咽喉 | 96篇 |
儿科学 | 322篇 |
妇产科学 | 225篇 |
基础医学 | 1694篇 |
口腔科学 | 377篇 |
临床医学 | 1305篇 |
内科学 | 4738篇 |
皮肤病学 | 179篇 |
神经病学 | 1479篇 |
特种医学 | 603篇 |
外科学 | 2149篇 |
综合类 | 26篇 |
预防医学 | 494篇 |
眼科学 | 132篇 |
药学 | 649篇 |
中国医学 | 9篇 |
肿瘤学 | 1520篇 |
出版年
2023年 | 126篇 |
2022年 | 212篇 |
2021年 | 405篇 |
2020年 | 283篇 |
2019年 | 346篇 |
2018年 | 408篇 |
2017年 | 329篇 |
2016年 | 404篇 |
2015年 | 428篇 |
2014年 | 591篇 |
2013年 | 798篇 |
2012年 | 1145篇 |
2011年 | 1198篇 |
2010年 | 662篇 |
2009年 | 685篇 |
2008年 | 1054篇 |
2007年 | 1120篇 |
2006年 | 1023篇 |
2005年 | 989篇 |
2004年 | 980篇 |
2003年 | 799篇 |
2002年 | 722篇 |
2001年 | 100篇 |
2000年 | 68篇 |
1999年 | 99篇 |
1998年 | 118篇 |
1997年 | 122篇 |
1996年 | 89篇 |
1995年 | 81篇 |
1994年 | 61篇 |
1993年 | 74篇 |
1992年 | 47篇 |
1991年 | 57篇 |
1990年 | 39篇 |
1989年 | 24篇 |
1988年 | 27篇 |
1987年 | 29篇 |
1986年 | 37篇 |
1985年 | 24篇 |
1984年 | 29篇 |
1983年 | 23篇 |
1982年 | 17篇 |
1981年 | 15篇 |
1980年 | 15篇 |
1978年 | 9篇 |
1977年 | 8篇 |
1972年 | 8篇 |
1968年 | 7篇 |
1967年 | 10篇 |
1966年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Role of Th1 and Th2 Cytokines in Immune Response to Uncomplicated Plasmodium falciparum Malaria
下载免费PDF全文
![点击此处可从《Clinical and Vaccine Immunology : CVI》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Donato Torre Filippo Speranza Massimo Giola Alberto Matteelli Roberto Tambini Gilberto Biondi 《Clinical and Vaccine Immunology : CVI》2002,9(2):348-351
The relative balance between Th1 and Th2 cytokines appears crucial, since the role of cytokines has been evaluated in several studies by comparison of clinically heterogeneous groups of patients. The aim of this study is to determine the role of proinflammatory Th1 cytokines, interleukin-12 (IL-12) and gamma interferon (IFN-γ), and anti-inflammatory Th2 cytokines, IL-4 and IL-10, in a homogeneous group of patients with uncomplicated Plasmodium falciparum malaria. Levels of IL-12, IFN-γ, Il-4, and IL-10 in serum for 20 adult patients and 15 healthy control subjects were determined by an immunoenzymatic assay. Serum levels of Th1 cytokines, IL-12 (8.6 ± 2.8 pg/ml; controls, 3.2 ± 0.7 pg/ml) and IFN-γ (39.2 ± 67.6 pg/ml; controls, 8.4 ± 6.3 pg/ml), were significantly increased at admission; 3 days later, levels of IL-12 in serum remained significantly high (8.8 ± 2.6 pg/ml), whereas IFN-γ levels returned to control values. The anti-inflammatory response of Th2 cytokines (IL-10 and IL-4) was distinct. Levels of IL-10 in serum were not significantly increased at day 0 and day 3 (306.6 ± 200.4 pg/ml and 56.6 ± 38.4 pg/ml, respectively; controls, 17.4 ± 9.0 pg/ml). In contrast, levels of IL-4 in serum were not increased on admission (3.4 ± 1.2 pg/ml; controls, 2.4 ± 0.8 pg/ml), but at day 3 a moderate and significant increase of IL-4 levels was observed (4.5 ± 1.7 pg/ml). In conclusion, the increase of Th1 cytokine IL-12 and IFN-γ levels during the acute phase of uncomplicated P. falciparum malaria may reflect an early and effective immune response regulated by proinflammatory Th1 cytokines, and in particular IFN-γ may play a role in limiting progression from uncomplicated malaria to severe and life-threatening complications. 相似文献
62.
Both Human Immunodeficiency Virus Cellular DNA Sequencing and Plasma RNA Sequencing Are Useful for Detection of Drug Resistance Mutations in Blood Samples from Antiretroviral-Drug-Naive Patients
下载免费PDF全文
![点击此处可从《Journal of clinical microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
63.
Hepatitis B virus (HBV) is a virus that infects about 350,000,000 people worldwide with a clinical spectrum of acute hepatitis, the healthy carrier state, cirrhosis and hepatocellular carcinoma (HCC). The outcome of HBV infection is the result of complicated viral-host interactions. As in other infections with non-cythopatic viruses, the immune response is thought to play a crucial role in disease pathogenesis but there is increasing evidence that a variety of viral mechanisms, some depending on the function of virally encoded proteins, have a profound impact on the infected hepatocytes, the liver microenvironment, and host anti-viral responses. Indeed, the virus has evolved multiple mechanisms to ensure its success in infecting a susceptible host. The essential aspects of the life cycle of HBV and the host immune response are reviewed and recent new developments in the molecular virology of HBV, including experimental animal models, in the role of accessory viral proteins in disease pathogenesis and HCC development and in the characterisation of the T cell response in the control of HBV infection, are highlighted. 相似文献
64.
Massimo Pignatelli Tareq W. Ansari Pat Gunter Dan Liu Shinji Hirano Masatoshi Takeichi Günter Klppel Nicholas R. Lemoine 《The Journal of pathology》1994,174(4):243-248
Epithelial cadherin (E-cadherin) is a Ca2+-dependent cell-cell adhesion molecule that connects cells via homotypic interactions. Its function is critical in the induction and maintenance of cell polarity and differentiation, and its loss of downregulation is associated with an invasive and poorly differentiated phenotype in colon and other tumours. We have used an avidin-biotin immunoperoxidase technique to localize E-cadherin in microwave-treated, paraffin-embedded sections from 36 patients with pancreatic adenocarcinomas. E-cadherin was expressed by normal ductal and acinar cells with typical membranous staining at the intercellular junctions. Loss of normal surface E-cadherin expression was found in 19/36 (53 per cent) tumours compared to the adjacent normal ductal cells. Abnormal E-cadherin expression was found more frequently in poorly differentiated (grade III) (6/7, 86 per cent) than in well-differentiated tumours (grade I) (4/14, 28 per cent) (P=0·012). Membranous E-cadherin expression was also lost more frequently in primary tumours with lymph node (stage III) (14/23, 61 per cent) and distant metastasis (stage IV) (2/2, 100 per cent) compared with 3/11 (27 per cent) lymph node-negative tumours (stage I) (P=0·043). In conclusions, our data indicate that loss of membranous E-cadherin expression is associated with high grade and advanced stage in pancreatic cancer. 相似文献
65.
Carlo Capelli Guglielmo Antonutto Paola Zamparo Massimo Girardis Pietro Enrico di Prampero 《European journal of applied physiology》1993,66(3):189-195
Summary The mechanical power (Wtot, W·kg–1) developed during ten revolutions of all-out periods of cycle ergometer exercise (4–9 s) was measured every 5–6 min in six subjects from rest or from a baseline of constant aerobic exercise [50%–80% of maximal oxygen uptake (VO2max)] of 20–40 min duration. The oxygen uptake [VO2 (W·kg–1, 1 ml O2 = 20.9 J)] and venous blood lactate concentration ([la]b, mM) were also measured every 15 s and 2 min, respectively. During the first all-out period, Wtot decreased linearly with the intensity of the priming exercise (Wtot = 11.9–0.25·VO2). After the first all-out period (i greater than 5–6 min), and if the exercise intensity was less than 60% VO2max, Wtot, VO2 and [la]b remained constant until the end of the exercise. For exercise intensities greater than 60% VO2max, VO2 and [la]b showed continuous upward drifts and Wtot continued decreasing. Under these conditions, the rate of decrease of Wtot was linearly related to the rate of increase of V [(d Wtot/dt) (W·kg–1·s–1) = 5.0·10–5 –0.20·(d VO2/dt) (W·kg–1·s–1)] and this was linearly related to the rate of increase of [la]b [(d VO2/dt) (W·kg–1·s–1) = 2.310–4 + 5.910–5·(d [la]b/dt) (mM·s–1)]. These findings would suggest that the decrease of Wtot during the first all-out period was due to the decay of phosphocreatine concentration in the exercising muscles occurring at the onset of exercise and the slow drifts of VO2 (upwards) and of Wtot (downwards) during intense exercise at constant Wtot could be attributed to the continuous accumulation of lactate in the blood (and in the working muscles). 相似文献
66.
Recovery of the endogenous beta cell function in the NOD model of autoimmune diabetes 总被引:7,自引:0,他引:7
Zorina TD Subbotin VM Bertera S Alexander AM Haluszczak C Gambrell B Bottino R Styche AJ Trucco M 《Stem cells (Dayton, Ohio)》2003,21(4):377-388
In light of accumulating evidence that the endocrine pancreas has regenerative properties and that hematopoietic chimerism can abrogate destruction of beta cells in autoimmune diabetes, we addressed the question of whether recovery of physiologically adequate endogenous insulin regulation could be achieved in the nonobese diabetic (NOD) mice rendered allogeneic chimerae. Allogeneic bone marrow (BM) was transplanted into NOD mice at the preclinical and overtly clinical stages of the disease using lethal and nonlethal doses of radiation for recipient conditioning. Islets of Langerhans, syngeneic to the BM donors, were transplanted under kidney capsules of the overtly diabetic animals to sustain euglycemia for the time span required for recovery of the endogenous pancreas. Nephrectomies of the graft-bearing organs were performed 14 weeks later to confirm the restoration of endogenous insulin regulation. Reparative processes in the pancreata were assessed histologically and immunohistochemically. The level of chimerism in NOD recipients was evaluated by flow cytometric analysis. We have shown that as low as 1% of initial allogeneic chimerism can reverse the diabetogenic processes in islets of Langerhans in prediabetic NOD mice, and that restoration of endogenous beta cell function to physiologically sufficient levels is achievable even if the allogeneic BM transplantation is performed after the clinical onset of diabetes. If the same pattern of islet regeneration were shown in humans, induction of an autoimmunity-free status by establishment of a low level of chimerism, or other alternative means, might become a new therapy for type 1 diabetes. 相似文献
67.
68.
Cova L Ratti A Volta M Fogh I Cardin V Corbo M Silani V 《Stem cells and development》2004,13(1):121-131
In the past few years research on stem cells has exploded as a tool to develop potential therapies to treat incurable neurodegenerative diseases. Stem cell transplantation has been effective in several animal models, but the underlying restorative mechanisms are still unknown. Several events such as cell fusion, neurotrophic factor release, endogenous stem cell proliferation, and transdifferentiation (adult cell acquisition of new unexpected identities) may explain therapeutic success, in addition to replacement of lost cells. This issue needs to be clarified further to maximize the potential for effective therapies. Preliminary stem transplantation trials have already been performed for some neurodegenerative diseases. There is no effective pharmacological treatment for amyotrophic lateral sclerosis, but recent preliminary data both in experimental and clinical settings have targeted it as an ideal candidate disease for the development of stem cell therapy in humans. This review summarizes recent advances gained in stem cell research applied to neurodegenerative diseases with a special emphasis to the criticisms put forward. 相似文献
69.
70.
Macchi C Popolizio A Casamorata F Bicchi S Pieroni A Molino Lova R Miniati B Gulisano M Catini C Conti AA Gensini GF 《Italian journal of anatomy and embryology = Archivio italiano di anatomia ed embriologia》2002,107(2):93-97
Fifty-four subjects, aged between 20 and 35 years, divided into two subgroups, respectively 30 healthy subjects (17 males and 13 females) and 24 subjects with "gonalgia sine materia" (13 males and 11 females) underwent isokinetic exercise test in order to compare their dominant limb with the not dominant one as regard as the strength of extensor and flexor muscles of the knee. No statistically significant difference was found in any of the studied parameters in the comparison between the dominant limb and the not dominant one, both within the subgroup of healthy subjects and within the subgroup of subjects with "gonalgia sine materia". Authors conclude that psychological features may play a preeminent role in the genesis, as well as in the maintenance of "gonalgia sine materia", thus confirming previous data available in medical literature. 相似文献