全文获取类型
收费全文 | 2441篇 |
免费 | 142篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 12篇 |
儿科学 | 181篇 |
妇产科学 | 57篇 |
基础医学 | 365篇 |
口腔科学 | 108篇 |
临床医学 | 215篇 |
内科学 | 427篇 |
皮肤病学 | 122篇 |
神经病学 | 237篇 |
特种医学 | 64篇 |
外科学 | 235篇 |
综合类 | 14篇 |
一般理论 | 2篇 |
预防医学 | 199篇 |
眼科学 | 20篇 |
药学 | 186篇 |
中国医学 | 4篇 |
肿瘤学 | 146篇 |
出版年
2023年 | 13篇 |
2022年 | 26篇 |
2021年 | 49篇 |
2020年 | 38篇 |
2019年 | 54篇 |
2018年 | 66篇 |
2017年 | 50篇 |
2016年 | 68篇 |
2015年 | 55篇 |
2014年 | 99篇 |
2013年 | 132篇 |
2012年 | 166篇 |
2011年 | 175篇 |
2010年 | 95篇 |
2009年 | 85篇 |
2008年 | 165篇 |
2007年 | 185篇 |
2006年 | 165篇 |
2005年 | 143篇 |
2004年 | 158篇 |
2003年 | 122篇 |
2002年 | 141篇 |
2001年 | 24篇 |
2000年 | 21篇 |
1999年 | 17篇 |
1998年 | 20篇 |
1997年 | 35篇 |
1996年 | 19篇 |
1995年 | 33篇 |
1994年 | 20篇 |
1993年 | 19篇 |
1992年 | 19篇 |
1991年 | 13篇 |
1990年 | 9篇 |
1989年 | 8篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 8篇 |
1984年 | 14篇 |
1983年 | 10篇 |
1982年 | 9篇 |
1981年 | 4篇 |
1980年 | 5篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 6篇 |
1975年 | 2篇 |
1974年 | 4篇 |
1973年 | 3篇 |
1965年 | 2篇 |
排序方式: 共有2594条查询结果,搜索用时 15 毫秒
21.
Effects of chronic treatment with valproate on serotonin-1A receptor binding and function 总被引:1,自引:0,他引:1
Valproate is effective in treating bipolar disorder characterized by rapid cycling or acute mania, although the mechanism of action is unclear. In contrast to other treatments for depression, 21 days of treatment in rats with valproate (100, 200 or 400 mg/kg) did not significantly alter the hypothermia induced by 8-hydroxy-2-(di-n-propyl)aminotetralin (8-OH-DPAT), an agonist at serotonin-1A receptors. Treatment with valproate also had no effect on radioligand binding to serotonin-1A, serotonin-2 or -adrenergic receptors. Based on these animal studies in frontal cortex and hippocampus, the therapeutic benefit of valproate in mood disorders does not appear to involve adaptive changes in serotonin-1A, serotonin-2 or -adrenergic receptor number. 相似文献
22.
Leena Hilakivi-Clarke 《Breast cancer research and treatment》1997,46(2-3):143-159
The possible role of personality patterns and psychosocial factors in breast cancer has been studied extensively, through both human and animal experiments. The data are conflicting, and the conclusions controversial. This review will serve two purposes. First, we present evidence that behavioral patterns most commonly linked to breast cancer risk are at least partly regulated by estrogens. This section will suggest that some estrogen-regulated behaviors may be markers of increased breast cancer risk. Second, we will briefly review recent findings in animals connecting psychosocial factors to cancer. We also will address the plausible biological mechanisms. The literature suggests that estrogens, particularly when exposure occurs during the critical developmental periods, such as in utero, puberty, pregnancy, and menopause, influence affective behaviors and increase breast cancer risk. The affective behaviors include depression, aggression, and alcohol intake. Thus, psychosocial and personality factors do not necessarily have a direct impact on breast cancer risk; instead, estrogens have a dual effect on behavior and on the breast. 相似文献
23.
Tarja Anttila Leena Tenkanen Sonja Lumme Maija Leinonen Randi Elin Gislefoss G?ran Hallmans Steinar Thoresen Timo Hakulinen Tapio Luostarinen P?r Stattin Pekka Saikku Joakim Dillner Matti Lehtinen Matti Hakama 《Cancer epidemiology, biomarkers & prevention》2005,14(2):385-389
OBJECTIVE: We assessed the risk of prostate cancer by exposure to Chlamydia trachomatis. METHOD: Seven hundred thirty eight cases of prostate cancer and 2,271 matched controls were identified from three serum sample banks in Finland, Norway, and Sweden by linkage to the population based cancer registries. RESULTS: A statistically significant inverse association (odds ratio, 0.69; 95% confidence interval, 0.51-0.94) was found. It was consistent by different serotypes and there was a consistent dose-response relationship. CONCLUSION: C. trachomatis infection is not likely to increase the risk of prostate cancer. Whether the inverse relationship is true or due to difficulties in measuring the true exposure in prostatic tissue by serology, confounders or other sources of error remain open. 相似文献
24.
Mikaela Porkholm Anna Raunio Reetta Vainionpää Tarja Salonen Juha Hernesniemi Leena Valanne Jarno Satopää Atte Karppinen Minna Oinas Olli Tynninen Virve Pentikäinen Sanna‐Maria Kivivuori 《Pediatric blood & cancer》2018,65(1)
1 Background
Diffuse intrinsic pontine gliomas (DIPGs) have a dismal prognosis. Previously, diagnosis was based on a typical clinical presentation and magnetic resonance imaging findings. After the start of the era of biopsies, DIPGs bearing H3 K27 mutations have been reclassified into a novel entity, diffuse midline glioma, based on the presence of this molecular alteration. However, it is not well established how clinically diagnosed DIPG overlap with H3 K27‐mutated diffuse midline gliomas, and whether rare long‐term survivors also belong to this group.2 Methods
We studied tumor samples obtained at diagnosis or upon autopsy from 23 children, including two long‐term survivors. Based on clinical, radiological, and histological findings, all tumors were previously diagnosed as DIPGs. All samples were analyzed for genetic alterations by next‐generation sequencing (NGS) and for protein expression by immunohistochemistry (IHC).3 Results
H3 K27 was mutated in NGS or IHC in 20 patients, excluding both long‐term survivors. One of these long‐term survivors harbored a mutation in IDH1, formerly considered to be an alteration absent in pediatric diffuse brainstem gliomas. Other altered genes in NGS included TP53 (10 patients), MET and PDGFRA (3 patients each), VEGFR and SMARCA4 (2 patients each), and PPARγ, PTEN and EGFR in 1 patient, respectively. IHC revealed cMYC expression in 15 of 24 (63%) of all samples, exclusively in the biopsies.4 Conclusions
Eighty‐seven percent of the tumors formerly diagnosed as DIPGs could be reclassified as H3 K27‐mutated diffuse midline gliomas. Both long‐term survivors lacked this alteration. Contrary to former conceptions, IDH1 mutations may occur also in pediatric brainstem gliomas. 相似文献25.
26.
Brooke Kania Erinie Mekheal Sindhusha Veeraballi Leena Bondili Michael Maroules 《Radiology Case Reports》2022,17(9):3097
Nonbacterial thrombotic endocarditis (NBTE) also called, "Marantic endocarditis" occurs due to an underlying hypercoagulable state causing tissue damage and upregulation of the coagulation cascade, with noninfective vegetation formation on heart valves. Mitral and aortic valves are most commonly involved. NBTE is rare, with an incidence of 1.6%, with 65 cases identified during a 10-year autopsy analysis. The most common malignancies associated with NBTE include gynecological cancers, lung cancer, gastric cancer, and pancreatic cancers with adenocarcinoma histology being the greatest risk. Herein, we present a rare case of a 55-year-old male who presented with acute hypoxic respiratory failure secondary to pulmonary embolism due to nonbacterial thrombotic endocarditis. He was found to have advanced pancreatic adenocarcinoma on further investigation of the 2.2 cm hypodense cystic mass in the distal pancreatic body and tail, and complex liver masses which were incidentally found on computed tomography angiography (CTA) of the chest. This is a rare phenomenon and clinicians have to consider the hypercoagulable state associated with cancers, particularly pancreatic adenocarcinoma, and the risk of NBTE. 相似文献
27.
Shuai Wang Xiaolu Wang Leena Penttinen Huiying Luo Yuhong Zhang Bo Liu Bin Yao Nina Hakulinen Wei Zhang Xiaoyun Su 《Toxins》2022,14(7)
The fungal secondary metabolite patulin is a mycotoxin widespread in foods and beverages which poses a serious threat to human health. However, no enzyme was known to be able to degrade this mycotoxin. For the first time, we discovered that a manganese peroxidase (MrMnP) from Moniliophthora roreri can efficiently degrade patulin. The MrMnP gene was cloned into pPICZα(A) and then the recombinant plasmid was transformed into Pichia pastoris X-33. The recombinant strain produced extracellular manganese peroxidase with an activity of up to 3659.5 U/L. The manganese peroxidase MrMnP was able to rapidly degrade patulin, with hydroascladiol appearing as a main degradation product. Five mg/L of pure patulin were completely degraded within 5 h. Moreover, up to 95% of the toxin was eliminated in a simulated patulin-contaminated apple juice after 24 h. Using Escherichia coli as a model, it was demonstrated that the deconstruction of patulin led to detoxification. Collectively, these traits make MrMnP an intriguing candidate useful in enzymatic detoxification of patulin in foods and beverages. 相似文献
28.
Ins Reigada Karmen Kapp Claire Maynard David Weinkove Marta Sofía Valero Elisa Langa Leena Hanski Carlota Gmez-Rincn 《Nutrients》2022,14(9)
Guarana (Paullinia cupana) is a widely consumed nutraceutical with various health benefits supported by scientific evidence. However, its indirect health impacts through the gut microbiota have not been studied. Caenorhabditis elegans is a useful model to study both the direct and indirect effects of nutraceuticals, as the intimate association of the worm with the metabolites produced by Escherichia coli is a prototypic simplified model of our gut microbiota. We prepared an ethanoic extract of guarana seeds and assessed its antioxidant capacity in vitro, with a 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, and in vivo, utilizing C. elegans. Additionally, we studied the impact of this extract on C. elegans lifespan, utilizing both viable and non-viable E. coli, and assessed the impact of guarana on E. coli folate production. The extract showed high antioxidant capacity, and it extended worm lifespan. However, the antioxidant and life-extending effects did not correlate in terms of the extract concentration. The extract-induced life extension was also less significant when utilizing dead E. coli, which may indicate that the effects of guarana on the worms work partly through modifications on E. coli metabolism. Following this observation, guarana was found to decrease E. coli folate production, revealing one possible route for its beneficial effects. 相似文献
29.
Reference Values for Echocardiography in Middle‐Aged Population: The Cardiovascular Risk in Young Finns Study
下载免费PDF全文
![点击此处可从《Echocardiography (Mount Kisco, N.Y.)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Saku Ruohonen Ph.D Juha W. Koskenvuo M.D. Ph.D. Maria Wendelin‐Saarenhovi M.D. Ph.D. Mikko Savontaus M.D. Ph.D. Mika Kähönen M.D. Ph.D. Tomi Laitinen M.D. Ph.D. Terho Lehtimäki M.D. Ph.D. Eero Jokinen M.D. Ph.D. Jorma Viikari M.D. Ph.D. Markus Juonala M.D. Ph.D. Leena Taittonen M.D. Ph.D. Päivi Tossavainen M.D. Ph.D. Merja Kallio M.D. Ph.D. Jeroen J. Bax M.D. Ph.D. Olli Raitakari M.D. Ph.D. 《Echocardiography (Mount Kisco, N.Y.)》2016,33(2):193-206
30.