全文获取类型
收费全文 | 42722篇 |
免费 | 4595篇 |
国内免费 | 3147篇 |
专业分类
耳鼻咽喉 | 457篇 |
儿科学 | 486篇 |
妇产科学 | 584篇 |
基础医学 | 4291篇 |
口腔科学 | 724篇 |
临床医学 | 5449篇 |
内科学 | 5817篇 |
皮肤病学 | 461篇 |
神经病学 | 1787篇 |
特种医学 | 1584篇 |
外国民族医学 | 15篇 |
外科学 | 4259篇 |
综合类 | 8674篇 |
现状与发展 | 18篇 |
一般理论 | 5篇 |
预防医学 | 3854篇 |
眼科学 | 971篇 |
药学 | 4772篇 |
49篇 | |
中国医学 | 2771篇 |
肿瘤学 | 3436篇 |
出版年
2024年 | 152篇 |
2023年 | 570篇 |
2022年 | 1540篇 |
2021年 | 2019篇 |
2020年 | 1570篇 |
2019年 | 1372篇 |
2018年 | 1422篇 |
2017年 | 1476篇 |
2016年 | 1293篇 |
2015年 | 1940篇 |
2014年 | 2407篇 |
2013年 | 2473篇 |
2012年 | 3305篇 |
2011年 | 3442篇 |
2010年 | 2559篇 |
2009年 | 2167篇 |
2008年 | 2415篇 |
2007年 | 2446篇 |
2006年 | 2257篇 |
2005年 | 2081篇 |
2004年 | 1828篇 |
2003年 | 2067篇 |
2002年 | 1765篇 |
2001年 | 1392篇 |
2000年 | 966篇 |
1999年 | 773篇 |
1998年 | 447篇 |
1997年 | 442篇 |
1996年 | 276篇 |
1995年 | 273篇 |
1994年 | 246篇 |
1993年 | 158篇 |
1992年 | 167篇 |
1991年 | 155篇 |
1990年 | 123篇 |
1989年 | 98篇 |
1988年 | 72篇 |
1987年 | 59篇 |
1986年 | 58篇 |
1985年 | 49篇 |
1984年 | 22篇 |
1983年 | 25篇 |
1982年 | 13篇 |
1981年 | 13篇 |
1979年 | 12篇 |
1977年 | 10篇 |
1976年 | 7篇 |
1974年 | 7篇 |
1973年 | 8篇 |
1972年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
151.
152.
Mersedeh Rohanizadegan Sarah Tracy Carolina I. Galarreta Tabitha Poorvu Terry L. Buchmiller Lynne M. Bird Judy A. Estroff Wen‐Hann Tan 《American journal of medical genetics. Part A》2020,182(8):1890-1895
Esophageal atresia (EA) is a congenital anomaly occurring in 2.3 per 10,000 live births. Due to advances in prenatal imaging, EA is more readily diagnosed, but data on the associated genetic diagnoses, other anomalies, and postnatal outcome for fetuses diagnosed prenatally with EA are scarce. We collected data from two academic medical centers (n = 61). Our data included fetuses with suspected EA on prenatal imaging that was confirmed postnatally and had at least one genetic test. In our cohort of 61 cases, 29 (49%) were born prematurely and 19% of those born alive died in the first 9 years of life. The most commonly associated birth defects were cardiac anomalies (67%) and spine anomalies (50%). A diagnosis was made in 61% of the cases; the most common diagnoses were vertebral defects, anal atresia, cardiac anomalies, tracheoesophageal fistula with esophageal atresia, radial or renal dysplasia, and limb anomalies association (43%, although 12% met only 2 of the criteria), trisomy 21 (5%), and CHARGE syndrome (5%). Our findings suggest that most fetuses with prenatally diagnosed EA have one or more additional major anomaly that warrants a more comprehensive clinical genetics evaluation. Fetuses diagnosed prenatally appear to represent a cohort with a worse outcome. 相似文献
153.
Shyh Ren Chiang Hung Jen Tang Ping Chin Chang Kuo Chen Cheng Wen Chien Ko Chung Hua Chen Yin Ching Chuang 《Journal of microbiology, immunology, and infection》2007,40(2):123-133
BACKGROUND AND PURPOSE: Vibrio vulnificus causes primary bacteremia and necrotizing wound infection, leading to high morbidity and mortality in humans. This study aimed to evaluate the antimicrobial effect of cefotaxime and minocycline on proinflammatory cytokine levels in a murine model of V. vulnificus infection. METHODS: We investigated the dynamics of proinflammatory cytokines and their modulation by antimicrobial agents using a murine model of V. vulnificus infection. The change in cytokine levels was followed over a time course to identify the antimicrobial activity of the drugs against V. vulnificus. BALB/c female mice were challenged with an intraperitoneal infection using a clinical invasive isolate of Vv05191, and their cytokine levels were assayed over various time points. RESULTS: Serum levels of tumor necrosis factor-alpha, interleukin (IL)-1 beta, and IL-6 post-infection were found to be inoculum dose-dependent and positively correlated to the subsequent fatality rate in the infected mice. With an inoculum of 6.6 x 10(6) colony-forming units and intraperitoneal administration of cefotaxime, minocycline, or both, the serum and peritoneal fluid cytokine levels increased and then declined gradually. Comparison of the 3 antimicrobial regimens revealed that the magnitude of reduction in cytokine levels was greatest in mice treated with cefotaxime-minocycline combination. Moreover, the peritoneal fluid cytokine level in the combination group was significantly lower than that in the groups treated with minocycline or cefotaxime alone. CONCLUSIONS: The current results support the superiority of the combination therapy in treating invasive V. vulnificus infections. 相似文献
154.
Mao-Tsair Lin Yin-Hsiu Chien Shyh-Dar Shyur Li-Hsin Huang Yi-Chi Chiang Da-Chin Wen Pei-Hsuan Liang Hwai-Chih Yang 《Annals of allergy, asthma & immunology》2006,96(5):744-748
BACKGROUND: X-linked agammaglobulinemia (XLA), characterized by a profound deficiency of all immunoglobulins and the absence of mature B cells, is caused by mutations in the gene encoding Bruton tyrosine kinase (BTK). Most patients have recurrent sinopulmonary infection. Infections usually occur in multiple locations across time, but single infection may be limited to one anatomic location. OBJECTIVES: To report a case of atypical XLA with recurrent pyoderma and to observe the immunologic changes in the patient in 10 years. METHODS: Immunologic investigations, skin wound culture, and molecular study with DNA sequencing were performed. RESULTS: The patient was originally diagnosed as having common variable immunodeficiency disease because of the presence of circulating B cells (CD19+ B cells: 7%) at 11 years old. On further evaluation at the age of 20 years, flow cytometric analysis of lymphocytes showed only 0.4% B cells. The molecular study with DNA sequencing of the patient showed a point mutation in complementary DNA 1630 A>G(p.R544G) in the BTK gene, indicating that the patient has XLA. The mutation analysis of the BTK gene revealed a normal DNA sequence in the other family members. CONCLUSIONS: This case is an important example of a possible presentation of XLA with a predominant skin manifestation, and it demonstrates that maintaining a high level of clinical suspicion is essential for the diagnosis of XLA in a child with recurrent pyoderma. 相似文献
155.
目的 应用核酸扩增产物测定的固相杂交酶联显色法(RT-PCR-ELISA)检测甲肝减毒活疫苗病毒滴度。方法 应用RT-PCR-ELISA。将标记有生物素的寡核苷酸引物所扩增的疫苗病毒基因产物。与微孔反应板上的特异性探针进行快速杂交,通过辣根过氧化物酶标记的链亲和素进行酶联显色。读取吸光度(A值)。判断结果。应用此法检测了11批甲肝活疫苗滴度。并与常规细胞培养法(CCID50)比较。结果 本方法与细胞培养法的敏感性相仿,具有简便、快速、特异的优点。结论 RTPCR-ELISA法有望代替常规细胞培养法应用于甲肝减毒活疫苗病毒滴度的检测。 相似文献
156.
低粘低切流场中渗透压对红细胞取向与变形的影响 总被引:2,自引:0,他引:2
本文研究了低粘低切流场中渗透压对红细胞取向与变形的影响,发现随着渗透压的变化,DI、DIor有相同的变化形式,而DId基本保持不变。说明低粘低切流场中,DId可能只与红细胞膜的力学性质有关。而DIor可能反映红细胞膜及其整体的弯曲弹性膜量。 相似文献
157.
PKA对跨膜型和分泌TNF—α胞毒效应的影响 总被引:4,自引:1,他引:4
目的:研究PKA对跨膜型TNFα(mTNF-α)杀瘤效应的影响。方法:用TNF生物活性检测方法在体外观察PKA激活剂和抑制剂对一型TNF-α杀伤不同肿瘤细胞的影响。结果:PKA激活剂Forskolin(10μmol/L)和抑制剂H8(15μmol/L)可分别增强和抑制sTNF-α对其第三靶细胞的胞毒活性,对其余4株耐受细胞却无逆转使用,而且对mTNF-α的胞毒效应无任何影响。此外,PKA活性增强, 相似文献
158.
目的 全面了解维吾尔族(维族)大学生的人格特征及其相关因素,为健康人格教育提供依据.方法 采用卡特尔16种人格因素问卷对666名维族大学生进行测试.结果 ①维族大学生在大部分人格特质上表现出与大学生常模显著不同的特征;②不同性别、来自不同地区、不同年级、不同专业的维族大学生人格特征之间存在一定的显著差异.结论 维族大学生人格有一定的民族性,而其人格发展受到很多因素的制约. 相似文献
159.
Chung-Chuan Chou Shengmei Zhou Hideki Hayashi Motoki Nihei Yen-Bin Liu Ming-Shien Wen San-Jou Yeh Michael C. Fishbein James N. Weiss Shien-Fong Lin Delon Wu Peng-Sheng Chen 《The Journal of physiology》2007,580(3):895-906
We hypothesize that remodelling of action potential and intracellular calcium (Cai ) dynamics in the peri-infarct zone contributes to ventricular arrhythmogenesis in the postmyocardial infarction setting. To test this hypothesis, we performed simultaneous optical mapping of Cai and membrane potential ( V m ) in the left ventricle in 15 rabbit hearts with myocardial infarction for 1 week. Ventricular premature beats frequently originated from the peri-infarct zone, and 37% showed elevation of Cai prior to V m depolarization, suggesting reverse excitation–contraction coupling as their aetiology. During electrically induced ventricular fibrillation, the highest dominant frequency was in the peri-infarct zone in 61 of 70 episodes. The site of highest dominant frequency had steeper action potential duration restitution and was more susceptible to pacing-induced Cai alternans than sites remote from infarct. Wavebreaks during ventricular fibrillation tended to occur at sites of persistently elevated Cai . Infusion of propranolol flattened action potential duration restitution, reduced wavebreaks and converted ventricular fibrillation to ventricular tachycardia. We conclude that in the subacute phase of myocardial infarction, the peri-infarct zone exhibits regions with steep action potential duration restitution slope and unstable Cai dynamics. These changes may promote ventricular extrasystoles and increase the incidence of wavebreaks during ventricular fibrillation. Whereas increased tissue heterogeneity after subacute myocardial infarction creates a highly arrhythmogenic substrate, dynamic action potential and Cai cycling remodelling also contribute to the initiation and maintenance of ventricular fibrillation in this setting. 相似文献
160.
压阻传感器在脉搏信号测试上的应用研究 总被引:3,自引:0,他引:3
脉搏是心脏和血管状态重要生理信息的外在反映,作者首先分析了在脉搏测量中传感器和放大电路设计的问题-即脉搏信号的特殊性,然后介绍膜型及囊型两种压力传感器;并给出脉搏信号放大电路。指出测量方法的进一步发展和对临床应用的意义。 相似文献