全文获取类型
收费全文 | 1838篇 |
免费 | 113篇 |
国内免费 | 9篇 |
专业分类
耳鼻咽喉 | 13篇 |
儿科学 | 61篇 |
妇产科学 | 60篇 |
基础医学 | 249篇 |
口腔科学 | 67篇 |
临床医学 | 202篇 |
内科学 | 386篇 |
皮肤病学 | 58篇 |
神经病学 | 117篇 |
特种医学 | 65篇 |
外科学 | 146篇 |
综合类 | 69篇 |
一般理论 | 1篇 |
预防医学 | 133篇 |
眼科学 | 34篇 |
药学 | 195篇 |
中国医学 | 7篇 |
肿瘤学 | 97篇 |
出版年
2024年 | 6篇 |
2023年 | 37篇 |
2022年 | 87篇 |
2021年 | 97篇 |
2020年 | 74篇 |
2019年 | 85篇 |
2018年 | 84篇 |
2017年 | 60篇 |
2016年 | 52篇 |
2015年 | 71篇 |
2014年 | 97篇 |
2013年 | 124篇 |
2012年 | 184篇 |
2011年 | 165篇 |
2010年 | 92篇 |
2009年 | 54篇 |
2008年 | 89篇 |
2007年 | 79篇 |
2006年 | 104篇 |
2005年 | 86篇 |
2004年 | 72篇 |
2003年 | 46篇 |
2002年 | 52篇 |
2001年 | 2篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1997年 | 4篇 |
1996年 | 6篇 |
1995年 | 2篇 |
1994年 | 8篇 |
1993年 | 5篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1983年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1967年 | 2篇 |
1945年 | 2篇 |
排序方式: 共有1960条查询结果,搜索用时 15 毫秒
91.
Gene expression profile of esophageal cancer in North East India by cDNA microarray analysis 总被引:2,自引:0,他引:2
Chattopadhyay I Kapur S Purkayastha J Phukan R Kataki A Mahanta J Saxena S 《World journal of gastroenterology : WJG》2007,13(9):1438-1444
AIM: To identify alterations in genes and molecular functional pathways in esophageal cancer in a high incidence region of India where there is a widespread use of tobacco and betel quid with fermented areca nuts. METHODS: Total RNA was isolated from tumor and matched normal tissue of 16 patients with esophageal squamous cell carcinoma. Pooled tumor tissue RNA was labeled with Cy3-dUTP and pooled normal tissue RNA was labeled with Cy5-dUTP by direct labeling method. The labeled probes were hybridized with human 10K cDNA chip and expression profiles were analyzed by Genespring GX V 7.3 (Silicon Genetics). RESULTS: Nine hundred twenty three genes were differentially expressed. Of these, 611 genes were upregulated and 312 genes were downregulated. Using stringent criteria (P ≤ 0.05 and ≥ 1.5 fold change), 127 differentially expressed genes (87 upregulated and 40 downregulated) were identified in tumor tissue. On the basis of Gene Ontology, four different molecular functional pathways (MAPK pathway, G-protein coupled receptor family, ion transport activity, and serine or threonine kinase activity) were most significantly upregulated and six different molecular functional pathways (structural constituent of ribosome, endopeptidase inhibitor activity, structural constituent of cytoskeleton, antioxidant activity, acyl group transferase activity, eukaryotic translation elongation factor activity) were most significantly downregulated. CONCLUSION: Several genes that showed alterations in our study have also been reported from a high incidence area of esophageal cancer in China. This indicates that molecular profiles of esophageal cancer in these two different geographic locations are highly consistent. 相似文献
92.
Srividya N. Iyer Sally S. Mustafa Laura Moro G. Eric Jarvis Ridha Joober Sherezad Abadi Nicola Casacalenda Howard C. Margolese Amal Abdel-Baki Martin Lepage Ashok Malla 《Revue canadienne de psychiatrie》2021,66(5):468
Objective:We aimed to investigate whether individuals with first-episode psychosis (FEP) receiving extended early intervention (EI) were less likely to experience suicidal ideation and behaviors than those transferred to regular care after 2 years of EI. Another objective was to examine the 5-year course of suicidality in FEP.Methods:We conducted a secondary analysis of a randomized controlled trial where 220 patients were randomized after 2 years of EI to receive extended EI or regular care for the subsequent 3 years. Suicidality was rated using the Brief Psychiatric Rating Scale. Linear mixed model analysis was used to study time and group effects on suicidality.Results:Extended EI and regular care groups did not differ on suicidality. There was a small decrease in suicidality over time, F(7, 1038) = 1.84, P = 0.077, with an immediate sharp decline within a month of treatment, followed by stability over the remaining 5 years. Patients who endorsed suicidality at entry (46.6%) had higher baseline positive, negative, and depressive symptoms. The 5-year course fell in 3 groups: never endorsed suicidality (33.9%), endorsed suicidality at low-risk levels (43.1%), and endorsed high-risk levels (23.0%). The high-risk group had a higher proportion of affective versus nonaffective psychosis diagnosis; higher baseline positive and depressive symptoms; higher 5-year mean depression scores, and fewer weeks of positive symptom remission over the 5-year course.Conclusions:The first month of treatment is a critical period for suicide risk in FEP. Although early reductions in suicidality are often maintained, our findings make the case for sustained monitoring for suicide risk management. 相似文献
93.
94.
Amal H. Abd El Hameed Osama E. Negm Osama M. El-Gamal Hala E. Hamouda Kholoud A. El Nouby Ghada M. Ismail 《Urologic oncology》2010,28(3):296-301
ObjectiveTo assess the influence of glutathione S-transferases M1 and T1 (GSTM1 and T1) genotype on the risk of bladder cancer in patients with urinary bilharziasis.Materials and methodsThis study was designed as a case-control study that involved 60 individuals who were enrolled into 3 equal groups. The first one included patients with bilharzial bladder cancer, the second one had those with nonmalignant urinary bilharziasis, and the last one was the control group. All of the participants were adult males, nonsmokers, and with matched ages. All of them underwent an assessment of the serum level of the total GST concentration and the polymerase chain reaction (PCR) was used for determination of the GSTM1 and T1 genotypes.ResultsThe lower most GST enzyme concentration was reported in patients with bilharzial bladder cancer (26 ± 4.4 ng/ml) with significant difference between it and that of the second group (36.8 ± 4.1 ng/ml, P < 0.05) and that of the controls (40.4 ± 4 ng/ml, P < 0.005). The PCR results have demonstrated that the frequency of combined GSTM1 and T1 genes deletion (M1–ve T1–ve) was significantly higher in cases of bladder cancer (40%) than those of the controls (5%, P < 0.005) and those of the second group (10%, P < 0.05). The unconditional logistic regression test revealed that patients with urinary bilharziasis and combined GSTM1 and T1 genes deletion are at a significant risk for malignant transformation (OR = 6.3, P < 0.05).ConclusionsPatients with urinary bilharziasis and GSTM1–ve and T1–ve genes might be at increased risk of bladder cancer. However, larger studies are needed for confirmation of these results. 相似文献
95.
96.
Witiw CD Abou-Hamden A Kulkarni AV Silvaggio JA Schneider C Wallace MC 《Neurosurgery》2012,71(3):626-631
BACKGROUND:: Cerebral cavernous malformations are brain vascular malformations associated with intracranial hemorrhage. It is unclear whether pregnancy is a risk factor for hemorrhage, yet there is speculation that it may be. OBJECTIVE:: To compare the risk of clinically significant hemorrhage during pregnancy and nonpregnancy. METHODS:: A total of 186 patients from the University of Toronto Vascular Malformations Study Group were enrolled. The obstetrical history of each patient was collected and matched to their neurological history from the records of the study group. All hemorrhagic events occurring during childbearing years were associated with either a defined pregnancy risk period or nonpregnancy period. Patients were also asked to recall advice that they received from health care professionals regarding risk of hemorrhage in pregnancy. RESULTS:: Among our patient population there were 349 pregnancies (283 live births) and 49 hemorrhages during childbearing years, 3 of which were during pregnancy but none during delivery or within 6 weeks post partum. The hemorrhage rate for pregnant women was 1.15% (95% confidence interval: 0.23-3.35) per person-year and 1.01% (95% confidence interval: 0.75-1.36) per person-year for nonpregnant women. Relative risk of pregnancy was 1.13 (95% confidence interval: 0.34-3.75) (P = .84). Neurosurgeons and obstetricians were the source of most hemorrhage risk advice. The majority of neurosurgeons suggested that the risk was unchanged, but the obstetricians were divided. Four patients never conceived, and 2 others began contraception because of the advice that they received. CONCLUSION:: The risk of intracranial hemorrhage from cerebral cavernous malformations is likely not changed during pregnancy, delivery, or post partum. ABBREVIATIONS:: CCM, cerebral cavernous malformationCI, confidence interval. 相似文献
97.
Amal Chandra Das Sakti Dey 《Bulletin of environmental contamination and toxicology》2013,90(6):666-672
An experiment was conducted under laboratory conditions to investigate the effect of three herbicides, viz., fenoxaprop, pendimethalin and paraquat, at their recommended field application rates (50 g, 1.0 kg and 1.0 kg a.i. ha?1, respectively), on the changes of microbial biomass C, N and P in relation to transformations and availability of plant nutrients in an alluvial soil (Typic Orchraqualf) from West Bengal, India. Application of herbicides, in general, significantly increased the microbial biomass C, N and P, resulting in greater availability of these plant nutrients in soil. The microbial biomass C was highly increased due to application of fenoxaprop (39.8 %) followed by paraquat (28.2 %). Application of pendimethalin led to the maximum stimulation of microbial biomass N (37.1 %), while microbial biomass P was increased by 15.2 % following the incorporation of paraquat into the soil. Compared to untreated control soil, the soil retained the highest amount of organic C (19.8 %) when it was treated with pendimethalin. A similar trend was recorded with fenoxaprop for total N (19.6 %) and exchangeable NH4 + (21.3 %) in soil. The stimulation of soluble NO3 ? was highest under fenoxaprop (22.3 %) followed by paraquat (20.7 %). Regarding the availability of P in soil, paraquat manifested greater stimulation (17.8 %) than fenoxaprop (15.4 %) or pendimethalin (13.1 %). Application of paraquat also gave the highest amount of total P (17.8 %) in the soil solution. 相似文献
98.
99.
Amal Jubran Gerald Lawm Joanne Kelly Lisa A. Duffner Gokay Gungor Eileen G. Collins Dorothy M. Lanuza Leslie A. Hoffman Martin J. Tobin 《Intensive care medicine》2010,36(5):828-835
Purpose
Patients who require mechanical ventilation are at risk of emotional stress because of total dependence on a machine for breathing. The stress may negatively impact ventilator weaning and survival. The purpose of this study was to determine whether depressive disorders in patients being weaned from prolonged mechanical ventilation are linked to weaning failure and decreased survival. 相似文献100.
Amal Kambal Gaela Mitchell Whitney Cary William Gruenloh Yunjoon Jung Stefanos Kalomoiris Catherine Nacey Jeannine McGee Matt Lindsey Brian Fury Gerhard Bauer Jan A Nolta Joseph S Anderson 《Molecular therapy》2011,19(3):584-593
Induced pluripotent stem cells (iPSCs) have radically advanced the field of regenerative medicine by making possible the production of patient-specific pluripotent stem cells from adult individuals. By developing iPSCs to treat HIV, there is the potential for generating a continuous supply of therapeutic cells for transplantation into HIV-infected patients. In this study, we have used human hematopoietic stem cells (HSCs) to generate anti-HIV gene expressing iPSCs for HIV gene therapy. HSCs were dedifferentiated into continuously growing iPSC lines with four reprogramming factors and a combination anti-HIV lentiviral vector containing a CCR5 short hairpin RNA (shRNA) and a human/rhesus chimeric TRIM5α gene. Upon directed differentiation of the anti-HIV iPSCs toward the hematopoietic lineage, a robust quantity of colony-forming CD133+ HSCs were obtained. These cells were further differentiated into functional end-stage macrophages which displayed a normal phenotypic profile. Upon viral challenge, the anti-HIV iPSC-derived macrophages exhibited strong protection from HIV-1 infection. Here, we demonstrate the ability of iPSCs to develop into HIV-1 resistant immune cells and highlight the potential use of iPSCs for HIV gene and cellular therapies. 相似文献