全文获取类型
收费全文 | 4026篇 |
免费 | 337篇 |
国内免费 | 39篇 |
专业分类
耳鼻咽喉 | 21篇 |
儿科学 | 163篇 |
妇产科学 | 72篇 |
基础医学 | 738篇 |
口腔科学 | 63篇 |
临床医学 | 536篇 |
内科学 | 876篇 |
皮肤病学 | 81篇 |
神经病学 | 264篇 |
特种医学 | 327篇 |
外科学 | 323篇 |
综合类 | 33篇 |
预防医学 | 325篇 |
眼科学 | 41篇 |
药学 | 355篇 |
中国医学 | 8篇 |
肿瘤学 | 176篇 |
出版年
2023年 | 59篇 |
2021年 | 67篇 |
2020年 | 110篇 |
2019年 | 41篇 |
2018年 | 119篇 |
2017年 | 95篇 |
2016年 | 97篇 |
2015年 | 92篇 |
2014年 | 131篇 |
2013年 | 159篇 |
2012年 | 134篇 |
2011年 | 132篇 |
2010年 | 113篇 |
2009年 | 146篇 |
2008年 | 110篇 |
2007年 | 125篇 |
2006年 | 117篇 |
2005年 | 91篇 |
2004年 | 68篇 |
2003年 | 70篇 |
2002年 | 77篇 |
2001年 | 87篇 |
2000年 | 61篇 |
1999年 | 69篇 |
1998年 | 97篇 |
1997年 | 102篇 |
1996年 | 89篇 |
1995年 | 81篇 |
1994年 | 54篇 |
1993年 | 55篇 |
1992年 | 66篇 |
1991年 | 84篇 |
1990年 | 98篇 |
1989年 | 105篇 |
1988年 | 98篇 |
1987年 | 92篇 |
1986年 | 89篇 |
1985年 | 90篇 |
1984年 | 62篇 |
1983年 | 42篇 |
1982年 | 36篇 |
1979年 | 44篇 |
1978年 | 41篇 |
1976年 | 44篇 |
1975年 | 50篇 |
1974年 | 41篇 |
1973年 | 53篇 |
1971年 | 44篇 |
1970年 | 34篇 |
1969年 | 37篇 |
排序方式: 共有4402条查询结果,搜索用时 31 毫秒
81.
82.
Diana Ivanova Oskan Tasinov Yoana Kiselova-Kaneva 《International journal of food sciences and nutrition》2014,65(6):740-744
This study aimed to establish the effect of Sambucus ebulus L. (SE) ripe fruit infusion on body weight, blood pressure, glucose levels, lipid profile and antioxidant markers in healthy volunteers in respect of its possible protective activity against cardiovascular diseases and other oxidative stress-related diseases. The study involved 21 healthy volunteers, aged between 20 and 59, BMI 23.12?±?1.31, who consumed 200?ml SE infusion/day for a period of 30?d. Blood samples were collected before and at the end of the intervention. Significant decrease in triglycerides (14.92%), total cholesterol (15.04%) and LDL-C (24.67%) was established at the end of the study. In addition, HDL-C/LDL-C ratio increased by 42.77%. Improved serum antioxidant capacity and total thiol levels were also established. The results presented in this first human intervention study with SE fruit infusion indicate the potential of the plant to improve lipid profile and serum antioxidant capacity in humans. 相似文献
83.
Saline contrast echocardiography for the detection of anomalous origin of pulmonary artery from aorta 下载免费PDF全文
Saurabh Kumar Gupta MD DM Abhishek Gupta MD 《Echocardiography (Mount Kisco, N.Y.)》2017,34(1):145-146
Saline contrast echocardiography is a well‐established modality for the diagnosis of right‐to‐left shunt lesions. In this brief report, we demonstrate, for the first time, its usefulness in the diagnosis of anomalous origin of right pulmonary artery from aorta. 相似文献
84.
85.
Dr. R. K. Dhiman MD DM V. A. Saraswat MD. DM A. Mishra PhD S. R. Naik MD 《Digestive diseases and sciences》1996,41(4):764-772
Prolonged esophageal pH monitoring is the most accurate method for detecting abnormal gastroesophageal reflux (GER) in patients with gastroesophageal reflux disease (GERD). However, some investigators have found that short-duration postprandial pH monitoring in the upright position is also useful, while others have failed to find such results. Therefore, we have compared a 6-hr period of pH monitoring (3-hr postprandial period after daytime meal and 3-hr supine period) with a total 24-hr period in detecting abnormal gastroesophageal reflux. Sixty-five patients (44 men, mean age 41.3 years) with GERD and 16 healthy volunteers (11 men, mean age 34.3 years) underwent 24-hr pH monitoring according to a standard protocol. Various reflux parameters during 24-hr pH monitoring were compared with reflux parameters during the 6-hr period. Abnormal GER was detected in 56 patients presenting with typical symptoms of GERD (sensitivity 86.2%). These patients could be further divided into upright (N=18), supine (N=15), and combined (N=23) refluxers, depending on the posture in which abnormal reflux occurred. Esophageal pH monitoring during the 3-hr postprandial upright period showed abnormal reflux in only 35 patients (sensitivity 53.8%;P<0.00005, compared with the 24-hr pH monitoring period). Abnormal GER was identified in 13 of 18 upright, 19 of 23 combined, and only one of 15 supine refluxers, as well as in two of nine patients with normal 24-hr pH-metry. However, inclusion of the 3-hr supine monitoring period in the 3-hr postprandial upright period improved detection of abnormal GER to 78.5% (51 patients;P=NS compared with 24-hr pH monitoring period). This was related mainly to improved detection of abnormal GER in supine refluxers (11 of 15; 73.3%). Esophageal acid exposure time correlated significantly with severity of esophagitis only during the total and supine periods of both the 24- and 6-hr periods and not during the upright period. Esophageal acid clearance correlated significantly with increasing grades of esophagitis for the supine and total periods only. We conclude that 3-hr postprandial pH monitoring, as has been conventionally practiced, is not appropriate in the detection of abnormal GER; inclusion of a supine period in the short-duration pH monitoring schedule increases the detection of pathological reflux. We therefore recommend that a supine period should be included in short-duration pH monitoring schedules. We also found that supine reflux was the most important factor in the development of esophagitis. 相似文献
86.
S. Coughlin BSc MSc PhD P. Calverley MB FRCP FRCPE J. Wilding DM FRCP 《Obesity reviews》2001,2(4):267-274
Sleep disordered breathing (SDB) is a complication of obesity estimated to occur in about 4–6% of overweight individuals. These respiratory disturbances during sleep incorporate a number of conditions including snoring, upper airway resistance syndrome and obstructive sleep apnoea syndrome (OSAS). It is thought that as well as having deleterious effects on sleep quality these conditions may also promote cardiovascular and hormonal changes leading to an elevated blood pressure and an increased incidence of cardiovascular morbidity. Evidence reviewed here points to an alteration in sympathovagal balance, baroreceptor sensitivity, insulin resistance and leptin, growth hormone and lipid levels. Whether these changes are a consequence of the associated obesity or the SDB itself remains to be proven. 相似文献
87.
B. S. Ramakrishna MD DM Prof. V. I. Mathan MD PhD 《Digestive diseases and sciences》1987,32(5):500-505
Colonic perfusion studies in 10 southern Indian patients with tropical sprue and nine matched healthy adults revealed a defect of water and sodium absorption from the colon in sprue. Heat-labile and heat-stable enterotoxin production was not detected in coliforms cultured from the feces of any of the 19 subjects. The 24-hr fecal bile acid output was increased in patients with sprue, but fecal aqueous bile acid concentrations remained within normal limits, and these did not correlate with defects in colonic water and sodium absorption. Fecal free fatty acid excretion was markedly increased in sprue. There was a negative correlation between fecal excretion of unsaturated free fatty acids and colonic water and sodium absorption. 相似文献
88.
In the last few years BCG vaccination has covered 97% of the newborns, but in 45% of them this vaccination proves to be low effective since no more than 2- or 3-mm long postvaccination cicatrix disappears by the 2-nd or 3-d year of their lives. The reasons of a low efficacy of BCG vaccination include inadequate BCG vaccination techniques, incomplete administration of the inoculation dose, etc. Cases of M. tuberculosis infection in children ineffectively vaccinated with BCG are 3 times more than among those effectively vaccinated and having postvaccination cicatrix. 相似文献
89.
90.
Factor VIII coagulant protein (VIII:C) functions as a critical cofactor with factor IXa, calcium ions, and phospholipid during the activation of factor X. In the course of this reaction, the activity of VIII:C is first increased and then is destroyed by one or more serine proteases that are part of the coagulation sequence. In this study, we have investigated the influence of platelets on the inactivation of VIII:C by plasmin. Platelets were separated from plasma proteins in the presence of granule release inhibitors and were incubated with plasmin and isolated VIII:C or the complex of purified VIII:C/von Willebrand factor (vWF); VIII:C activity and antigen levels were assessed over time. In the presence of platelets, the isolated VIII:C showed an initial increase in VIII:C activity that was not present when platelets were absent, and the VIII:C/vWF showed an increase in VIII:C activity over that seen when platelets were absent. In addition, platelets stabilized VIII:C activity over a one-hour time course when compared with buffer. The VIII:C antigen did not increase and decreased slowly whether platelets were present or absent. Preincubating the platelets with ristocetin, collagen, or plasmin did not alter the results, and experiments using platelets from a patient with severe von Willebrand's disease also showed a pattern similar to that seen with normal platelets. Experiments using fixed platelets or phospholipid vesicles showed that they did not support the activation reaction or delay the inactivation reaction. These studies demonstrate that platelets modulate the activation and inactivation of VIII:C by plasmin, apparently by a mechanism that is independent of the platelet release reaction. 相似文献