全文获取类型
收费全文 | 20314篇 |
免费 | 1559篇 |
国内免费 | 136篇 |
专业分类
耳鼻咽喉 | 242篇 |
儿科学 | 573篇 |
妇产科学 | 342篇 |
基础医学 | 2492篇 |
口腔科学 | 281篇 |
临床医学 | 2271篇 |
内科学 | 4887篇 |
皮肤病学 | 276篇 |
神经病学 | 1379篇 |
特种医学 | 838篇 |
外科学 | 2990篇 |
综合类 | 574篇 |
一般理论 | 9篇 |
预防医学 | 1469篇 |
眼科学 | 660篇 |
药学 | 1305篇 |
3篇 | |
中国医学 | 149篇 |
肿瘤学 | 1269篇 |
出版年
2023年 | 101篇 |
2022年 | 156篇 |
2021年 | 315篇 |
2020年 | 222篇 |
2019年 | 373篇 |
2018年 | 374篇 |
2017年 | 329篇 |
2016年 | 327篇 |
2015年 | 368篇 |
2014年 | 556篇 |
2013年 | 818篇 |
2012年 | 1174篇 |
2011年 | 1132篇 |
2010年 | 732篇 |
2009年 | 723篇 |
2008年 | 1187篇 |
2007年 | 1249篇 |
2006年 | 1263篇 |
2005年 | 1183篇 |
2004年 | 1115篇 |
2003年 | 1050篇 |
2002年 | 982篇 |
2001年 | 350篇 |
2000年 | 330篇 |
1999年 | 279篇 |
1998年 | 239篇 |
1997年 | 230篇 |
1996年 | 191篇 |
1995年 | 229篇 |
1994年 | 192篇 |
1993年 | 151篇 |
1992年 | 214篇 |
1991年 | 183篇 |
1990年 | 189篇 |
1989年 | 179篇 |
1988年 | 194篇 |
1987年 | 183篇 |
1986年 | 154篇 |
1985年 | 150篇 |
1984年 | 152篇 |
1983年 | 150篇 |
1982年 | 141篇 |
1981年 | 129篇 |
1980年 | 128篇 |
1979年 | 102篇 |
1978年 | 101篇 |
1977年 | 117篇 |
1957年 | 88篇 |
1956年 | 88篇 |
1955年 | 92篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Dongbing Lai Emma C. Johnson Sarah Colbert Gayathri Pandey Grace Chan Lance Bauer Meredith W. Francis Victor Hesselbrock Chella Kamarajan John Kramer Weipeng Kuang Sally Kuo Samuel Kuperman Yunlong Liu Vivia McCutcheon Zhiping Pang Martin H. Plawecki Marc Schuckit Jay Tischfield Leah Wetherill Yong Zang Howard J. Edenberg Bernice Porjesz Arpana Agrawal Tatiana Foroud 《Alcoholism, clinical and experimental research》2022,46(3):374-383
2.
Anela Stanic Denis Rybin Francis Cannata Carole Hohl Jennifer Brody Jessie Gaeta 《AIDS care》2021,33(1):1-9
ABSTRACT The lack of stable housing can impair access and continuity of care for patients living with human immunodeficiency virus (HIV). This study investigated the relationship between housing status assessed at multiple time points and several core HIV-related outcomes within the same group of HIV patients experiencing homelessness. Patients with consistently stable housing (CSH) during the year were compared to patients who lacked CSH (non-CSH group). The study outcomes included HIV viral load (VL), CD4 counts, and health care utilization. Multivariable and propensity weighted analyses were used to assess outcomes adjusting for potential group differences. Of 208 patients, 88 (42%) had CSH and 120 (58%) were non-CSH. Patients with CSH had significantly higher proportion of VL suppression and higher mean CD4 counts. The frequency of nurse visits in the CSH group was less than a half of that in the non-CSH group. Patients with CSH were less likely to be admitted to the medical respite facility, and if admitted, their length of stay was about a half of that for the non-CSH group. Our study findings show that patients with CSH had significantly better HIV virologic control and immune status as well as improved health care utilization. 相似文献
3.
Dynamic LVOT Obstruction and Aortic Stenosis in the Same Patient: A Case of Challenging Doppler Hemodynamics
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)
Matthew W. Parker M.D. Francis J. Kiernan M.D. 《Echocardiography (Mount Kisco, N.Y.)》2015,32(6):1030-1032
We present a patient with both dynamic left ventricular outflow tract obstruction and valvular aortic stenosis. The aortic valve was calcified, and velocities and gradients measured by continuous‐wave Doppler met standard criteria for severe aortic stenosis. The increased subvalvular velocities invalidated assumptions of the simplified Bernoulli equation; correction using the longer form of the Bernoulli equation suggested a lower but still significant gradient. The complex shape of the subvalvular spectral Doppler envelope indicated supranormal systolic function and dynamic left ventricular outflow obstruction. Left heart catheterization with an end‐hole catheter was required to determine the subvalvular and valvular components of the obstruction. 相似文献
4.
5.
Bernard Natukunda Grace Ndeezi Lay See Er Francis Bajunirwe Gayle Teramura Meghan Delaney 《ISBT科学丛刊》2019,14(4):366-373
6.
7.
乐敏飞 《中国公共卫生管理》2016,(4):477-479
目的调查宁波市北仑区0~14岁儿童哮喘发病率、发病规律及危险因素,为制定防治措施提供参考。方法2013年1月-2014年1月,采用整群抽样法抽取北仑区19所学校0~14岁儿童为调查对象进行问卷调查,对筛查出的疑似哮喘儿童进行确诊,并对其人口学特征进行分析,采用logistic回归方程分析危险因素。结果调查收回有效问卷23 781份,共检出哮喘患儿534例,发病率为2.25%,男女发病率比例为1.92:1。其中发病较轻患儿占44.01%,中度占31.46%,重度占24.53%。发病时间以换季、冬季为主,分别占35.96%、32.02%。多因素logistic回归分析显示,呼吸道感染、药物过敏史、家族过敏史和食物过敏史是儿童哮喘发病的危险因素(P<0.05)。结论北仑区儿童哮喘发病率较高,具有性别和季节发病差异,应加大对患病危险因素的宣传,规范标准化治疗方案,减少儿童哮喘疾病的发生。 相似文献
8.
Agenesis of the Gallbladder Revisited Laparoscopically 总被引:1,自引:0,他引:1
Najam Azmat M.D. Kenneth R. Francis M.D. Neal Mandava M.D. Walter F. Pizzi M.D. 《The American journal of gastroenterology》1993,88(8):1269-1270
Gallbladder agenesis is an extremely rare disease. Necropsy incidence has been reported to be 0.016%. Failure lo locate the gallbladder at the time of a planned cholecystectomy can be very challenging. We report such a case during a laparoscopic cholecystectomy. The indication for surgery in these patients are complaints of gallbladder symptoms along with a false-positive ultrasound study. During exploration, an abnormal location of the gallbladder has to be excluded. Ectopic gallbladder locations include intrahepatic, lesser omentum, retroperitoneal, retrohepatic, within the falciform ligament, retroduodenal, and retrohepatic areas. Thorough exploration and cholangiography are essential. Embryologically, the gallbladder and cystic duct arise from the caudal portion of the hepatic bud. All of the previously reported cases of gallbladder agenesis have shown an absence of both the gallbladder and cystic duct. We report an embryological oddity wherein a patent cystic duct was found along with an agenetic gallbladder. This is the first case report of this finding, along with this being the first absent gallbladder discovered laparoscopically. 相似文献
9.
Reactive oxygen species and human spermatozoa: physiology and pathology 总被引:20,自引:1,他引:19
The role of reactive oxygen species (ROS) in the pathophysiology of human sperm function has been emphasized in recent years. ROS production in semen has been associated with loss of sperm motility, decreased capacity for sperm–oocyte fusion and loss of fertility. There is a current presumption that the most prolific source of ROS in sperm suspensions is an NADPH oxidase located in leukocytes or in spermatozoa which produces superoxide which is further converted to peroxide by the action of superoxide dismutase. Hydrogen peroxide has been recognized as the most toxic oxidizing species for human spermatozoa, which are very sensitive to lipid peroxidation owing to the high content of polyunsaturated fatty acids in their plasma membrane, though this is not the sole mechanism by which sperm function might be impaired by ROS. Although the excessive production of ROS is detrimental to human spermatozoa, there is a growing body of evidence which suggests that ROS are also involved in the physiological control of some sperm functions. This review focuses on the nature and source of the ROS generated by human spermataozoa as well as their operational mechanisms and their effects, which may be detrimental or beneficial. 相似文献
10.
BACKGROUND: Human serum albumin (HAS) is used to treat hypoproteinaemia in neonates and as a volume expander. The aim of this study was to quantify the decrease in serum concentration of ionized magnesium ([Mg2+]) when human serum albumin is added to neonatal serum in vitro. METHODS: Human serum albumin was added to 20 cord serum samples of term infants to reach incremental concentrations of 0 to 20.0 g/l and [Mg2+] were measured. RESULTS: Serum [Mg2+] decreased significantly with the addition of serum albumin. At incremental serum albumin concentration of 10 to 20 g/l, which is within the range of the desired aim in the treatment of hypoalbuminaemia, the magnitude of the decrease in serum [Mg2+] was approximately 0.041 to 0.052 mmol/l (10 to 13 per cent) from the average baseline value. CONCLUSION: The addition of albumin causes a decrease in [Mg2+]. From this in vitro study we speculate that fast infusion of albumin in human neonates may potentially cause a clinically significant decrease in serum [Mg2+]. 相似文献