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   16137篇
  免费   696篇
  国内免费   88篇
耳鼻咽喉   203篇
儿科学   278篇
妇产科学   132篇
基础医学   1904篇
口腔科学   395篇
临床医学   1111篇
内科学   3997篇
皮肤病学   313篇
神经病学   1076篇
特种医学   720篇
外科学   2757篇
综合类   51篇
预防医学   499篇
眼科学   431篇
药学   1355篇
中国医学   38篇
肿瘤学   1661篇
  2023年   71篇
  2022年   147篇
  2021年   247篇
  2020年   125篇
  2019年   183篇
  2018年   258篇
  2017年   201篇
  2016年   243篇
  2015年   236篇
  2014年   351篇
  2013年   504篇
  2012年   753篇
  2011年   900篇
  2010年   527篇
  2009年   482篇
  2008年   846篇
  2007年   949篇
  2006年   936篇
  2005年   992篇
  2004年   1009篇
  2003年   1011篇
  2002年   1010篇
  2001年   377篇
  2000年   424篇
  1999年   380篇
  1998年   234篇
  1997年   192篇
  1996年   186篇
  1995年   162篇
  1994年   146篇
  1993年   151篇
  1992年   255篇
  1991年   220篇
  1990年   222篇
  1989年   218篇
  1988年   211篇
  1987年   186篇
  1986年   154篇
  1985年   156篇
  1984年   128篇
  1983年   92篇
  1982年   53篇
  1981年   56篇
  1980年   52篇
  1979年   83篇
  1978年   65篇
  1977年   57篇
  1973年   55篇
  1969年   54篇
  1968年   53篇
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
1.
Objective: Polyunsaturated fatty acids n-3 (PUFA n-3) have shown effects in reducing tumor growth, in particular eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) abundantly present in fish oil (FO). When these fatty acids are provided in the diet, they alter the functions of the cells, particularly in tumor and immune cells. However, the effects of α-linolenic fatty acid (ALA), which is the precursor of EPA and DHA, are controversial. Thus, our objective was to test the effect of this parental fatty acid. Methods: Non-tumor-bearing and tumor-bearing Wistar rats (70 days) were supplemented with 1 g/kg body weight of FO or Oro Inca® (OI) oil (rich in ALA). Immune cells function, proliferation, cytokine production, and subpopulation profile were evaluated. Results: We have shown that innate immune cells enhanced phagocytosis capacity, and increased processing and elimination of antigens. Moreover, there was a decrease in production of pro-inflammatory cytokines (tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6)) by macrophages. Lymphocytes showed decreased proliferation capacity, increased cluster of differentiation 8 (CD8+) subpopulation, and increased TNF-α production. Conclusions: Oil rich in ALA caused similar immune modulation in cancer when compared with FO.  相似文献   
2.

Background

On April 1, 2016, the Ministerial ordinance was enforced, and musculoskeletal examination of the extremities was made mandatory. From 2008, the University of us started musculoskeletal direct examination. To expand the examination, from 2016, we started to use the marksheet-type questionnaire. This study aimed to report the results of a musculoskeletal examination and investigate the association between musculoskeletal examination and age/gender and reports the reliability of the collected questionnaire data.

Methods

Direct musculoskeletal examination was performed in K school by 7 orthopedic surgeons. A marksheet-type screening questionnaire was distributed to all the elementary and junior high school students in Tsukuba and Hitachiomiya cities. The rates of abnormal findings for scoliosis, standing flexion, full squatting with the heels on the floor, general joint laxity, and standing on one leg, torticollis, and flat feet were calculated. We compared the results of the questionnaire and direct examination and calculated sensitivity, specificity, and odds ratio.

Results

A total of 1844 students in K school had direct examination, and 22,494 questionnaires were able to correct in Tsukuba and Hitachiomiya cities. The rates of abnormal findings in direct examination/questionnaire in scoliosis, standing flexion, full squat, general joint laxity, standing on one leg, torticollis and flat foot were 18.7% (344/1842)/5.1% (1094/21441), 20.2% (372/1841)/26.6% (5817/22078), 6.2% (114/1832)/6.9% (1516/22101), 7.5% (1648/22252), 4.9% (1100/22077), 2.2% (31/1844)/1.2% (272/21687), and 12.5% (231/1842)/8.7% (1785/20871), respectively. Sensitivities of the questionnaire for scoliosis, stand flexion, full squatting, torticollis, and flat feet were 16.8% (53/316), 67.9% (250/368), 48.2% (55/114), 18.9% (7/37), and 32.2% (65/202), respectively.

Conclusion

We reported the result of musculoskeletal examination. Accuracy and reliability of this questionnaire were not satisfactory. To perform high quality musculoskeletal examinations, we will aim to increase the quality of screening methods.  相似文献   
3.
4.
5.
Two patients with mesenteric panniculitis are presented. In the first patient, a provisional diagnosis of ileus was made, based on the clinical features and imaging data. Laparotomic findings showed that the ileum was bound tightly by a fibrous strip and dilated, with thickened and swollen mesentery. Incision of the fibrous strip was performed, and the clinical symptoms were improved. The second patient was strongly suspected to have mesenteric panniculitis, from characteristic features on abdominal computed tomography and barium enema. Conservative therapy was effective in this case. We emphasize the variety of clinical courses in mesenteric panniculitis, requiring selection of the most suitable treatment.  相似文献   
6.
7.
Obstructive sleep apnea syndrome (OSAS) is a common condition characterized by repetitive sleep‐induced collapse of the upper airways. It is associated with increased risk for hypertension, ischemic heart disease, cerebral stroke, and traffic accidents. In contrast, gastroesophageal reflux disease (GERD) is a very common disorder defined as various symptoms or esophageal mucosal damage generated by the abnormal reflux of gastric contents into the esophagus. Patients with OSAS have been reported to have a high prevalence of gastroesophageal reflux (GER) symptoms. The increase of transdiaphragmatic pressure in parallel with the large negative intrathoracic pressure produced during apnea events may directly lead to GER. In addition, some studies have demonstrated improvement in GERD with the application of continuous positive airway pressure, most consistently effective treatment for OSAS. However, GER dose not occur with every apnea. Moreover, the common conditions observed in patients with OSAS, including obesity or alcohol ingestion, are also predisposing factors for GER. A more recent investigation in over 1000 subjects failed to show a causal link between both diseases. Thus, the potential relationship between OSAS and GERD remains controversial. Inconsistencies in definitions of both diseases or sampling biases may contribute to the confusing results.  相似文献   
8.
9.
The contents of free and conjugated polyamines in cyst fluids of brain tumours were analysed. The putrescine and N1-acetylspermidine levels in cyst fluids of malignant brain tumours were significantly higher than those of benign tumours. The free spermidine levels in malignant and benign tumours were about the same, while the total spermidine levels were higher in malignant than those in benign tumours. These results suggest that polyamine levels in cyst fluids reflect the altered polyamine metabolism in brain tumours.  相似文献   
10.
This article describes the construction and use of a new end graft holder during coronary artery bypass grafting (CABG). The instrument consists of a pinching device attached to a flexible arm and a fixation clamp. This device provides secure stabilization and enables excellent positioning of the graft without producing graft injury.  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