首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   5338篇
  免费   326篇
  国内免费   30篇
耳鼻咽喉   60篇
儿科学   143篇
妇产科学   192篇
基础医学   505篇
口腔科学   123篇
临床医学   490篇
内科学   1118篇
皮肤病学   74篇
神经病学   311篇
特种医学   207篇
外国民族医学   3篇
外科学   920篇
综合类   74篇
一般理论   10篇
预防医学   414篇
眼科学   209篇
药学   453篇
中国医学   28篇
肿瘤学   360篇
  2024年   11篇
  2023年   57篇
  2022年   157篇
  2021年   221篇
  2020年   161篇
  2019年   223篇
  2018年   296篇
  2017年   214篇
  2016年   199篇
  2015年   200篇
  2014年   265篇
  2013年   348篇
  2012年   475篇
  2011年   483篇
  2010年   276篇
  2009年   218篇
  2008年   333篇
  2007年   303篇
  2006年   266篇
  2005年   228篇
  2004年   192篇
  2003年   190篇
  2002年   153篇
  2001年   32篇
  2000年   19篇
  1999年   15篇
  1998年   20篇
  1997年   19篇
  1996年   20篇
  1995年   19篇
  1994年   8篇
  1993年   5篇
  1992年   11篇
  1991年   7篇
  1990年   8篇
  1989年   5篇
  1988年   2篇
  1987年   5篇
  1986年   2篇
  1985年   2篇
  1983年   2篇
  1982年   2篇
  1980年   2篇
  1979年   4篇
  1978年   2篇
  1975年   5篇
  1973年   2篇
  1971年   2篇
  1968年   1篇
  1963年   1篇
排序方式: 共有5694条查询结果,搜索用时 16 毫秒
51.
β-Thalassemia major (β-TM) is an inherited disease and efforts have been made in several countries to reduce the number of affected births. In the present study, we aimed to evaluate the Iranian thalassemia prevention program, considered to be an important program in the region. The time period of the present study ranges from 2007–2009, during which new thalassemic births and the relevant causes were evaluated throughout the country. A cross-sectional analytical study was conducted at the Iranian Blood Transfusion Organization (IBTO), Tehran, Iran. A questionnaire was forwarded to all blood centers of the IBTO so as to obtain information about the new cases of thalassemia and the causes of these thalassemic births. Provincial thalassemia societies also received the questionnaires so that screening and prenatal diagnosis (PND) errors would be recorded. The results showed that 755 new thalassemia cases were born during 2007–2009 with the average fall in affected thalassemia births of 80.82%. The main cause of the new births was attributed to unregistered “timeless religious marriages” based on the conventions of the Sunni community which accounted for 43.17% of all new cases mainly having occurred in Sistan & Baluchestan Province. Not using PND was evaluated to be another main cause. Although the prevention program has led to a great reduction in thalassemic births, new measures are required, including research on how to make the program compatible with social and economic conventions and norms of Sistan & Baluchestan Province. The province of Kohgiluyeh Boyer Ahmad also needs to be revisited in terms of the program efficacy.  相似文献   
52.
53.
Journal of Assisted Reproduction and Genetics - Ferroptosis is associated with oxidative stress (OS) and is caused by iron-dependent lipid-peroxidative damage, but its role in PE is unclear. The...  相似文献   
54.
55.
56.
Aim: Several tests are available for aphasia screening following stroke. However, some of them have shortcomings such as need of specialist knowledge, low sensitivity and/or specificity and lengthy administration time. Our study aims to evaluate the language component of the Addenbrooke's Cognitive Examination – Revised (ACE‐R) as a screening tool for aphasia in stroke patients. Methods: The language component of ACE‐R was administered to consecutive patients admitted to a post‐acute stroke unit. Patients who were medically unstable or had a significant history of sensory impairment or mental health issues were excluded. The test was administered by two junior doctors with basic training in ACE‐R administration. Patients recruited were also assessed by an experienced speech and language therapist (SLT). The results of the two assessments were documented by a different member of the team and the SLT results were used as the benchmark to calculate the ACE‐R language component sensitivity and specificity. Results: Fifty‐nine participants were recruited and 27 of them were women. The mean age was 72 (SD 11.9). Thirty‐four participants had left and 11 right hemisphere stroke. Fourteen had bilateral affection. Six participants were left handed. A cut‐off value of 22/26 of ACE‐R language component showed 100% specificity and 83.1% sensitivity, while a cut‐off value of 16/26 had 88.2% specificity and 100% sensitivity. Conclusion: Our results suggest that the language component of ACE‐R has a satisfactory sensitivity and specificity compared with other screening tests used in strokes. It is easy to administer and free to use.  相似文献   
57.
The cells as a tissue component need to viscoelastic, biocompatible, biodegradable, and wettable extracellular matrix for their biological activity. In this study, in order to prepare biomedical polyurethane elastomers with good mechanical behavior and biodegradability, a series of novel polyester–polyether- based polyurethanes (PUs) were synthesized using a two-step bulk reaction by melting pre-polymer method, taking 1,4-Butanediol (BDO) as chain extender, hexamethylene diisocyanate as the hard segment, and poly (tetramethylene ether) glycol (PTMEG) and poly (ε-caprolactone diol) (PCL-Diol) as the soft segment without a catalyst. The soft to the hard segment ratio was kept constant in all samples. Polyurethane characteristics such as thermal and mechanical properties, wettability and water adsorption, biodegradability, and cellular behavior were changed by changing the ratio of polyether diol to polyester diol composition in the soft segment. Our present work provides a new procedure for the preparation of engineered polyurethanes in surface properties and biodegradability, which could be a good candidate for bone, cartilage, and skin tissue engineering.  相似文献   
58.
59.
Neurologic sequelae remain a common and destructive problem in patients with acute kidney injury. The objective of this study was to evaluate the possible neuroprotective effect of erythropoietin (EPO) on motor impairments following bilateral renal ischemia (BRI) in two time points after reperfusion: short term (24 h) and long term (1 week). Male Wistar rats underwent BRI or sham surgery. EPO or saline administration was performed 30 min before surgery (1000 U/kg, i.p.). Explorative behaviors and motor function of the rats were evaluated by open field, rotarod, and wire grip tests. Plasma concentrations of blood urea nitrogen (BUN) and creatinine (Cr) were significantly enhanced in BRI rats 24 h after reperfusion. BRI group had only an increased level of BUN but not Cr 1 week after reperfusion. Impairment of balance function by BRI was not reversed by EPO 24 h after reperfusion, but counteracted 7 days after renal ischemia. Muscle strength had no significant differences between the groups. BRI group had a decrease in locomotor activity, and EPO could not reverse this reduction in both time points of the experiment. Although EPO could not be offered as a potential neuroprotective agent in the treatment of motor dysfunctions induced by BRI, it could be effective against balance dysfunction 1 week after renal ischemia.  相似文献   
60.
Our study aimed to determine the number of couples with normal hemoglobin (Hb) electrophoresis and low-borderline hematological values, which may come up with a clinically critical status in their offspring. The number of couples at risk for severe α-thalassemia (α-thal) needed to be estimated before recommending genetic counseling and prenatal diagnosis (PND). During the past 14 years, from at least 7000 referrals, 754 couples were investigated for α-thal by direct mutation detection methods followed by reverse strip assay and α-globin gene sequencing for inconclusive cases. Detection of silent β-thalassemia (β-thal) mutations was done in suspected cases by complete β-globin gene sequencing. We were able to provide a molecular diagnosis in 87.3% (658/754) of couples. A total of 9.1% (60/658) may have a clinically significant hemoglobinopathy in their offspring. Significant conditions included hydrops fetalis (20.0%; 12/60), certain Hb H (β4) genotypes (78.3%; 47/60) and β-thal intermedia (β-TI) (1.7%; 1/60). The diagnostic flowchart for couples with microcytic hypochromic anemia in countries with a high prevalence of hemoglobinopathies should include α and β gene sequencing. As our results indicate, every nine out of 100 of these couples will face significant hemoglobinopathies and every two out of 100 can carry Hb Bart’s (γ4) hydrops fetalis in their pregnancies. For such cases, PND should be utilized to allow the carrier couples to decide whether or not to abort the fetus.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号