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   41298篇
  免费   2292篇
  国内免费   142篇
耳鼻咽喉   535篇
儿科学   2594篇
妇产科学   738篇
基础医学   5083篇
口腔科学   1128篇
临床医学   2966篇
内科学   7487篇
皮肤病学   1185篇
神经病学   2432篇
特种医学   1207篇
外科学   6149篇
综合类   1376篇
一般理论   17篇
预防医学   2107篇
眼科学   1482篇
药学   4096篇
  1篇
中国医学   357篇
肿瘤学   2792篇
  2023年   334篇
  2022年   971篇
  2021年   1636篇
  2020年   912篇
  2019年   1006篇
  2018年   1416篇
  2017年   1022篇
  2016年   1347篇
  2015年   1376篇
  2014年   2018篇
  2013年   2287篇
  2012年   3206篇
  2011年   3140篇
  2010年   1883篇
  2009年   1481篇
  2008年   2102篇
  2007年   2140篇
  2006年   1969篇
  2005年   1743篇
  2004年   1628篇
  2003年   1385篇
  2002年   1184篇
  2001年   825篇
  2000年   752篇
  1999年   626篇
  1998年   279篇
  1997年   228篇
  1996年   228篇
  1995年   192篇
  1994年   167篇
  1993年   141篇
  1992年   373篇
  1991年   367篇
  1990年   380篇
  1989年   350篇
  1988年   303篇
  1987年   259篇
  1986年   254篇
  1985年   251篇
  1984年   189篇
  1983年   136篇
  1982年   79篇
  1981年   83篇
  1980年   76篇
  1979年   124篇
  1978年   85篇
  1977年   96篇
  1976年   83篇
  1975年   81篇
  1973年   74篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Eight healthy, young adult males underwent three separate, 10-min 70 degrees head-up tilts (HUT) over a period of nine days, in order to assess the intra- and inter-individual variability of cardiovascular and plasma norepinephrine (NE) responses to the manoeuvre. Cardiovascular parameters and plasma NE were measured in the basal state and at 2-min intervals during the HUT. The results indicate that: (1) the intra-individual variability is a smaller component of the total variability of both cardiovascular and plasma NE responses to HUT; (2) the variability in cardiovascular parameters is smaller than that in plasma NE levels, both basal and in response to postural stress; (3) there does not appear to be any difference in variability when expressed either as the maximal or the mean response to HUT; and (4) there does not appear to be an increase in the variability of the measured parameters over the duration of the HUT.  相似文献   
102.
103.
Recurrence of hepatitis C (HCV) following liver transplantation is common. Herpesvirus reactivation following transplant may have an immunomodulatory effect resulting in increased HCV replication. We studied whether cytomegalovirus (CMV) and human herpesvirus-6 (HHV-6) may be associated with HCV recurrence and viral load after transplant. We prospectively followed 66 HCV liver-transplant recipients with serial viral load testing for CMV and HHV-6. Infection and viral load were correlated with the development of biopsy-proven HCV recurrence and HCV viral loads. Histologic recurrence of HCV occurred in 41/66 (62.1%) patients. In the primary analysis, CMV infection and disease, and HHV-6 infection were not associated with HCV recurrence. Peak CMV and HHV-6 viral loads were not significantly different in patients with and without recurrence. No correlation was observed between HCV viral loads at 1 and 3 months post-transplant and peak HHV-6 or CMV viral loads. In a subgroup analysis, HHV-6 infection was associated with the development of more severe recurrence (hepatitis and/or fibrosis score > or = 2) (p = 0.01). Also, fibrosis scores at last follow up were higher in patients with CMV disease (1.67 vs. 0.56; p = 0.016) and in patients with HHV-6 infection (1.18 vs. 0.55; p = 0.031). In conclusion, HHV-6 and CMV infection and viral load were not associated with increased overall rates of HCV recurrence or HCV viral load after liver transplantation but may be associated with more severe forms of recurrence.  相似文献   
104.
A total of 1000 slit-skin smears were taken from multiple sites (both ear lobules, right elbow, dorsal aspect of middle phalanx of the left finger, and dorsum of middle phalanx of the right foot) from 558 leprosy patients. There were 319 sets (1595 smears) from untreated patients and 681 sets (3405 smears) from the treated group. The duration of treatment varied from 6 months (multidrug therapy) to 7 years (dapsone monotherapy). The ear lobules gave significantly higher values for the bacterial index (BI) compared to toes and fingers in the untreated group. The morphological index (MI) was also significantly higher from the ear lobules compared to toes, elbows, and fingers. In five patients from the untreated group, bacilli were found in some other sites when the earlobes did not reveal any. In the treated group, all sites yielded similar BI and MI values, the figures being lowest from elbows and toes but not different statistically. In 20 long-treated patients, bacilli were detected at sites other than the ear lobules. In 28 patients, sites other than the ear lobules gave a higher MI and in 20 patients, solid bacilli were seen at sites other than the ear lobules.  相似文献   
105.
106.
107.
A study of DNA content by flow cytometry revealed a significant difference between rhabdomyosarcomas, which were mainly non-diploid, and other sarcomas of children which were mainly diploid (p = 0.01). There was no association between DNA ploidy and survival or aggressive behaviour of the tumour as indicated for example by advanced clinical stage or unfavourable histology. While DNA ploidy correlated with age, it did not correlate with any other clinical characteristic. The apparent lack of prognostic value of DNA content may have been masked by some high CV values and overridden by the effect of chemotherapy which was the most significant variable in determining a patient's survival (p = 0.00005).  相似文献   
108.
A total of 675 strains of Salmonella bareilly received from different parts of India and France during 1959-92 were phage typed using six bacteriophages. Overall typability achieved was 90.8% with 23 distinct phage types excluding a group of untypable strains. Phage types have been defined in octal code. Simpson''s coefficient was applied for diversity index having a value of 0.839. This system was found to be reproducible, stable and epidemiologically useful.  相似文献   
109.
Behavioural studies were conducted on a random sample of 38 glass bangle workers engaged in various occupations and exposed to high ambient temperature (38.2 +/- 3.4 degrees C) and radiant heat (46.2 +/- 5.1 degrees C) during their work in the glass bangle industries at Firozabad, India. Twenty-two control subjects of similar age and socio-economic status unexposed to heat during their work were also studied for comparison. The digit span test, digit symbol test, Bourdon-Wiersma vigilance test, flicker fusion test and Maudsley personality inventory (MPI) were used to assess the behavioural changes induced by the existing heat stress. The mean scores of immediate memory were much lower in the exposed population than in the controls thereby indicating impairment of immediate memory in the study group. The visuo-motor coordination and vigilance were also significantly affected. Visual perception showed a downward trend among the glass bangle workers, although the MPI test indicated no personality changes.  相似文献   
110.
Gastrointestinal manifestations of dengue fever are mainly in the form of bleeding or liver function abnormalities. Dengue fever presenting as acute colitis-like picture is not reported to date. We report a 50-year-old man with dengue fever presenting with lower gastrointestinal bleeding and colonoscopic features of acute inflammatory colitis.  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