全文获取类型
收费全文 | 1699篇 |
免费 | 110篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 49篇 |
妇产科学 | 26篇 |
基础医学 | 204篇 |
口腔科学 | 76篇 |
临床医学 | 157篇 |
内科学 | 381篇 |
皮肤病学 | 22篇 |
神经病学 | 141篇 |
特种医学 | 67篇 |
外国民族医学 | 1篇 |
外科学 | 198篇 |
综合类 | 46篇 |
一般理论 | 3篇 |
预防医学 | 115篇 |
眼科学 | 35篇 |
药学 | 155篇 |
中国医学 | 5篇 |
肿瘤学 | 133篇 |
出版年
2023年 | 22篇 |
2022年 | 58篇 |
2021年 | 85篇 |
2020年 | 52篇 |
2019年 | 64篇 |
2018年 | 91篇 |
2017年 | 45篇 |
2016年 | 48篇 |
2015年 | 55篇 |
2014年 | 59篇 |
2013年 | 72篇 |
2012年 | 126篇 |
2011年 | 98篇 |
2010年 | 78篇 |
2009年 | 62篇 |
2008年 | 73篇 |
2007年 | 83篇 |
2006年 | 71篇 |
2005年 | 83篇 |
2004年 | 56篇 |
2003年 | 70篇 |
2002年 | 57篇 |
2001年 | 23篇 |
2000年 | 21篇 |
1999年 | 16篇 |
1998年 | 21篇 |
1997年 | 8篇 |
1996年 | 8篇 |
1995年 | 5篇 |
1993年 | 7篇 |
1992年 | 15篇 |
1991年 | 10篇 |
1990年 | 16篇 |
1989年 | 14篇 |
1988年 | 17篇 |
1987年 | 13篇 |
1986年 | 12篇 |
1985年 | 15篇 |
1984年 | 14篇 |
1983年 | 6篇 |
1982年 | 5篇 |
1980年 | 4篇 |
1979年 | 12篇 |
1978年 | 9篇 |
1977年 | 4篇 |
1976年 | 4篇 |
1975年 | 5篇 |
1974年 | 4篇 |
1973年 | 5篇 |
1970年 | 3篇 |
排序方式: 共有1820条查询结果,搜索用时 15 毫秒
31.
Serum levels of carbonic anhydrase IX (CAIX) and the tissue inhibitor of metalloproteinase 1 (TIMP-1) have been demonstrated to be associated with clinical outcomes. Elevated TIMP-1 levels have been associated with a poor prognosis of breast cancer. Therefore, this study was performed to explore the relationships between serum CAIX, TIMP-1, and clinical outcomes. One hundred and five female breast cancer patients, who do not receive adjuvant therapy at Mansoura University Hospital were recruited with informed consent for this study. Preoperative serum levels of CAIX and TIMP-1 were measured using an enzyme-linked immunosorbent assay. Among the breast cancer patients, 16.1 and 20.9 % had elevated TIMP-1 and CAIX l levels, respectively. In addition, 13.3 % had elevated both CAIX and TIMP-1 levels. Elevated serum levels CAIX was significantly associated with advanced histological grade, estrogen receptor status and progesterone receptor status. Moreover, Elevated TIMP-1 was significantly associated with number of tumor-positive lymph nodes and advanced histological grade. In Kaplan–Meier analysis, the disease-free survival (DFS) was lower in patients with high serum levels of CAIX and TIMP-1 compared to patients with normal serum concentration of CAIX and TIMP-1. Including TIMP-1, CAIX, and established prognostic factors in the multivariate analysis, the presence of elevated CAIX and TIMP-1 levels remained independent predictors of overall survival time (OS). A high serum TIMP-1 and CAIX levels were significantly associated with poorer DFS and OS among Egyptian primary breast cancer patients with elevated serum levels of CAIX and TIMP-1. 相似文献
32.
Nida Yousef Molly Philips Ira Shetty Vivian Wei Cui Frank Zimmerman David A. Roberson 《Pediatric cardiology》2014,35(7):1099-1107
Transesophageal echocardiography (TEE) is used in atrial flutter or fibrillation (AFF) before electric cardioversion to detect intracardiac thrombi. Previous studies have described the use of TEE to diagnose intracardiac thrombi in the left atrium and left atrial appendage, which has an incidence of 8 % among patients without congenital heart disease (CHD). In their practice the authors have noted a significant incidence of intracardiac thrombi in other structures of patients with CHD and AFF. This study aimed to determine the incidence and location of intracardiac thrombi using TEE in patients with CHD requiring electric cardioversion of AFF and to compare the use of TEE and transthoracic echo (TTE) to detect intracardiac thrombus in this population. A retrospective chart review of TEE and TTE findings for all patients with CHD who had electric cardioversion of AFF at our institution from 2005 to 2013 was conducted. The diagnosis, presence, and location of intracardiac thrombus were determined. The TEE and TTE results were compared. The study identified 27 patients with CHD who met the study entry criteria at our institution between 2005 and 2013. Seven of these patients had a single ventricle with Fontan palliation. All the patients presented with AFF and had TEE before electric cardioversion. No patients were excluded from the study. The patients ranged in age from 2 to 72 years (median, 21 years) and weighed 17–100 kg (median, 65 kg). The duration of AFF before TEE and attempted cardioversion ranged from 1 day to 3 weeks (median, 3.5 days). Intracardiac thrombus was present in 18 % (5/27) of the patients and in 57 % (4/7) of the Fontan patients with AFF. No embolic events were reported acutely or during a 6-month follow-up period. Among patients with CHD who present with AFF, a particularly high incidence of intracardiac thrombi is present in the Fontan patients that may be difficult to detect by TTE. Thorough TEE examination of the Fontan and related structures is indicated before electric cardioversion of AFF. The incidence of intracardiac thrombus in CHD patients is more than double that reported in non-CHD patients. 相似文献
33.
Fatemeh Bitarafan Seyed Yousef Seyedena Mahdi Mahmoudi Masoud Garshasbi 《Journal of clinical laboratory analysis》2020,34(12):e23544
BackgroundThe extremely high genetic heterogeneity of hearing loss due to diverse group of genes encoding proteins required for development, function, and maintenance of the complex auditory system makes the genetic diagnosis of this disease challenging. Up to now, 121 different genes have been identified for nonsyndromic hearing loss (NSHL), of which 76 genes are responsible for the most common forms of NSHL, autosomal recessive nonsyndromic hearing loss (ARNSHL).MethodsAfter excluding mutations in the most common ARNSHL gene, GJB2, by Sanger sequencing, genetic screening for a panel of genes responsible for hereditary hearing impairment performed in 9 individuals with ARNSHL from unrelated Iranian consanguineous pedigrees.ResultsOne compound heterozygote and eight homozygote variants, of which five are novel, were identified: CDH23:p.(Glu1970Lys), and p.(Ala1072Asp), GIPC3:p.(Asn82Ser), and (p.Thr41Lys), MYO7A:p.[Phe456Phe]; p.[Met708Val], and p.(Gly163Arg), TECTA:p.(Leu17Leufs*19), OTOF:c.1392+1G>A, and TRIOBP:p.(Arg1068*). Sanger sequencing confirmed the segregation of the variants with the disease in each family.ConclusionFinding more variants and expanding the spectrum of hearing impairment mutations can increase the diagnostic value of molecular testing in the screening of patients and can improve counseling to minimize the risk of having affected children for at risk couples. 相似文献
34.
Adekunle Dawodu Yousef M. Abdulrazzaq Abdulbari Bener Inge Kappel Larry Liddle Mani Varghese 《American journal of human biology》1996,8(3):341-345
A prospective study of biological factors for low birthweight (LBW) among UAE nationals in the Al Ain Medical District was undertaken from 15 January 1992 to 14 January 1993, using a case control method. All 293 mothers of LBW infants and an equal number of mothers of the next normal weight infants born after the LBW infant were studied. Of the 3,485 live births, 293 (8.4%) were LBW (less than 2,500 g). Maternal age less than 25 years, lighter weight at booking, nulliparity, first cousin marriage and short interpregnancy interval (IPI) of 3 months or less significantly increased the risk of LBW in this population. After adjusting for other biologic confounders, only low maternal weight and short IPI significantly increased the risk of LBW. Modification of these biologic risk factors would help to reduce the incidence of LBW among the UAE population. © 1996 Wiley-Liss, Inc. 相似文献
35.
Aim: We assess the accuracy of torque controllers after several aging processes and the bacterial leakage on implant-abutment complexes (IAC). Methods: A total of 12 spring-type and 12 friction-type torque controllers and 48 IAC (24 conical and 24 hexagonal connections) were evaluated. Chemical, mechanical, temperature, and pressure-aging methods were applied individually to replicate clinical use. Torque controller accuracy was analyzed before and after aging using a calibrated gauge. To assess bacterial leakage, the IAC were suspended in a bacterial medium for 24 h. Direct Contact Test (DCT) and Polymerase Chain Reaction Test (RT-PCR) analyzed the infiltration of F. nucleatum and P. gingivalis into the IAC micro-gap. Results: A significant decrease in torque after 10 days of aging was found. The spring-type torque controller was affected the most, regardless of the aging method (P < 0.05). PCR results indicated that all groups exhibited significantly more bacterial leakage, regardless of the method used (P < 0.05). The conical IAC demonstrated more bacterial leakage of P. gingivalis compared with the hexagonal IAC (P = 0.07). DCT found bacterial growth in the IAC only before aging and was not identified after aging. Conclusion: Aging affects torque accuracy. A reduction in force was noticed after 10 days. The conical IAC exhibits more bacterial leakage, although this was not statistically significant. 相似文献
36.
Tantawy Azza Abdel Gawad Adly Amira Abdel Moneam Abdeen Mai Seif El Din Salah Nouran Yousef 《Neurogenetics》2020,21(3):159-167
neurogenetics - Evidence about the link between glucocerebrosidase (GCase) and parkinsonism is growing. Parkinsonism was described in adult type 1 Gaucher disease (GD); few case reports described... 相似文献
37.
38.
Sabbah Ataya Mohamed M. Z. Ahmed Mohamed M. El-Sayed Seleman Khalil Hajlaoui Fahamsyah H. Latief Ahmed M. Soliman Yousef G. Y. Elshaghoul Mohamed I. A. Habba 《Materials》2022,15(4)
In the current study, a 2 mm thick low-carbon steel sheet (A283M—Grade C) was joined with a brass sheet (CuZn40) of 1 mm thickness using friction stir spot welding (FSSW). Different welding parameters including rotational speeds of 1000, 1250, and 1500 rpm, and dwell times of 5, 10, 20, and 30 s were applied to explore the effective range of parameters to have FSSW joints with high load-carrying capacity. The joint quality of the friction stir spot-welded (FSSWed) dissimilar materials was evaluated via visual examination, tensile lap shear test, hardness test, and macro- and microstructural investigation using SEM. Moreover, EDS analysis was applied to examine the mixing at the interfaces of the dissimilar materials. Heat input calculation for the FSSW of steel–brass was found to be linearly proportional with the number of revolutions per spot joint, with maximum heat input obtained of 11 kJ at the number of revolutions of 500. The temperature measurement during FSSW showed agreement with the heat input dependence on the number of revolution. However, at the same revolutions of 500, it was found that the higher rotation speed of 1500 rpm resulted in higher temperature of 583 °C compared to 535 °C at rotation speed of 1000 rpm. This implies the significant effect for the rotation speed in the increase of temperature. The macro investigations of the friction stir spot-welded joints transverse sections showed sound joints at the different investigated parameters with significant joint ligament between the steel and brass. FSSW of steel/brass joints with a number of revolutions ranging between 250 to 500 revolutions per spot at appropriate tool speed range (1000–1500 rpm) produces joints with high load-carrying capacity from 4 kN to 7.5 kN. The hardness showed an increase in the carbon steel (lower sheet) with maximum of 248 HV and an increase of brass hardness at mixed interface between brass and steel with significant reduction in the stir zone hardness. Microstructural investigation of the joint zone showed mechanical mixing between steel and brass with the steel extruded from the lower sheet into the upper brass sheet. 相似文献
39.
Yousef GM Stephan C Scorilas A Ellatif MA Jung K Kristiansen G Jung M Polymeris ME Diamandis EP 《The Prostate》2003,56(4):287-292
BACKGROUND: Many members of the human kallikrein gene family are differentially expressed in cancer and a few have potential as diagnostic/prognostic markers. KLK14 is a newly discovered human kallikrein gene that is mainly expressed in the central nervous system and endocrine tissues. Since KLK14 was found to be regulated by steroid hormones in prostate cancer cell lines, we hypothesized that it will be differentially expressed in prostate cancer tissues compared to their normal counterparts. METHODS: Matched prostate tissue samples from the cancerous and non-cancerous parts of the same prostates were obtained from 100 patients who underwent radical prostatectomy. Quantitative analysis of KLK14 expression levels were performed by real-time RT-PCR using SYBR Green I dye on the LightCycler trade mark system. Associations with clinico-pathological parameters were analyzed. RESULTS: KLK14 overexpression in the cancerous compared to non-cancerous tissue was found in 74% of patients (P < 0.001). Mean level of expression was 154 arbitrary units (Au) in cancerous tissues and 14.2 Au in the non-cancerous tissues. The ratio of the cancerous to non-cancerous KLK14 expression values was higher in patients with late stage (stage III) compared to stage II (P = 0.002), and in grade 3 compared to grade 1/2 tumors (P = 0.001). A statistically significant increase was also observed in patients with higher in Gleason score (>6) compared to Gleason score = 6 tumors (P = 0.027). No correlation was found between KLK14 tissue expression levels and serum prostate-specific antigen. CONCLUSIONS: KLK14 expression is significantly higher in cancerous compared to non-cancerous prostatic tissue. The up-regulation of the KLK14 gene in advanced and more aggressive tumors may indicate a possible role for the hK14 protein in tumor spread and opens the possibility of hK14 being a candidate new marker for prostate cancer diagnosis and prognosis. 相似文献
40.
Abdulaziz Joury MD Mona Alshehri MD Arjun Mahendra MD Mahmoud Anteet MD Mohammad A. Yousef MD Abdul M. Khan MD 《Journal of clinical apheresis》2020,35(2):131-137
Hypertriglyceridemia-induced acute pancreatitis (HGAP) is the third most common etiology of acute pancreatitis. HGAP can be attributed to genetic disturbances in triglyceride metabolism or multiple secondary causes. Here, we presented three cases for HGAP and explored different therapeutic approaches for treating HGAP. A case series of three patients who presented with HGAP and underwent different therapeutic approaches was conducted. The first patient was a 37-year-old male who presented with nonsevere HGAP; he was treated with conservative therapy with insulin and heparin infusion, which resulted in clinical and laboratory improvement. The second patient was a 64-year-old male with human immunodeficiency virus on multiple highly active antiretroviral therapy. He presented with severe HGAP and multiorgan failure. After initiation of therapeutic plasma exchange, his HGAP resolved. The third patient was a 28-year-old male who presented with recurrent episodes of HGAP; his conservative therapy failed and was eventually escalated to therapeutic plasma exchange (TPE). HGAP can be attributed to genetic disturbances of lipid or secondary etiologies. A nonsevere form of HGAP can be managed with conventional therapy including insulin and heparin; however, severe HGAP may require TPE. 相似文献