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   246870篇
  免费   11936篇
  国内免费   435篇
耳鼻咽喉   3260篇
儿科学   7695篇
妇产科学   5108篇
基础医学   35262篇
口腔科学   6124篇
临床医学   19549篇
内科学   54660篇
皮肤病学   6529篇
神经病学   21974篇
特种医学   7294篇
外国民族医学   102篇
外科学   30753篇
综合类   1048篇
一般理论   67篇
预防医学   22509篇
眼科学   4868篇
药学   17163篇
中国医学   760篇
肿瘤学   14516篇
  2023年   1356篇
  2022年   1111篇
  2021年   3909篇
  2020年   2357篇
  2019年   4325篇
  2018年   7826篇
  2017年   5161篇
  2016年   5205篇
  2015年   5815篇
  2014年   6187篇
  2013年   9832篇
  2012年   16835篇
  2011年   16895篇
  2010年   8480篇
  2009年   6393篇
  2008年   14434篇
  2007年   15403篇
  2006年   14231篇
  2005年   14037篇
  2004年   13116篇
  2003年   11944篇
  2002年   11347篇
  2001年   6474篇
  2000年   6560篇
  1999年   5807篇
  1998年   983篇
  1997年   815篇
  1996年   782篇
  1995年   707篇
  1992年   3357篇
  1991年   2997篇
  1990年   2858篇
  1989年   2623篇
  1988年   2439篇
  1987年   2265篇
  1986年   2150篇
  1985年   1954篇
  1984年   1439篇
  1983年   1224篇
  1979年   1236篇
  1978年   874篇
  1977年   812篇
  1975年   829篇
  1974年   1010篇
  1973年   1021篇
  1972年   964篇
  1971年   946篇
  1970年   886篇
  1969年   927篇
  1968年   810篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.

Background

Since recent reports have shown that (-)-Epigallocatechin-3-gallate (EGCG) could be used for treating proliferative and inflammatory disorders, we explored its use for the management of corneal chemical burns.

Materials and methods

Initially, EGCG was assayed on the rabbit corneal epithelial cell line RCE1(5T5) to establish the best testing conditions, and to avoid unwanted outcomes in the experimental animals. Then, we studied its effects on cell proliferation, cell cycle progression and cell differentiation. Afterwards, we instilled EGCG in experimental grade II corneal alkali burns in mice, three times a day up to 21 days, and evaluated by slit lamp examination and histological sections of corneal epithelial, corneal endothelial and stromal edema, as well as the presence of inflammatory cells and neovascularization.

Results

EGCG reduced cell growth and led to a decline in the proportion of proliferative cells in a concentration dependent manner. At 10 μM, EGCG promoted cell differentiation, an effect not related with apoptosis or cytotoxicity. When 10 μM EGCG was instilled in corneal alkali burns in mice three times a day up to 21 days, EGCG significantly reduced corneal opacity and neovascularization. The improved clinical appearance of the cornea was associated to a controlled epithelial growth; epithelial morphology was similar to that observed in normal epithelium and contrasted with the hyperproliferative, desquamating epithelium observed in control burn wounds. EGCG reduced corneal, stromal and endothelial edema, and wound inflammation.

Conclusion

This work constitutes the first evidence for the use of EGCG in the acute phase of a corneal alkali burn, representing a possible novel alternative to improve patient outcomes as an add-on therapy.  相似文献   
3.
4.
5.
6.
7.

Objective

To systematically review literature on uptake and timeliness of diphtheria-tetanus-pertussis, measles-mumps-rubella, and/or polio-containing vaccines in infants who were born preterm, with a low birth weight, and/or with chronic health conditions that were diagnosed within the first 6?months of life.

Methods

Using a standardized search strategy developed by a medical librarian, records were extracted from MEDLINE, Embase, Database of Abstracts of Reviews of Effects, and CINAHL up to May 8, 2018.

Results

Out of the 1997 records that were screened, we identified 21 studies that met inclusion criteria. Eleven studies assessed vaccine coverage and/or timeliness in preterm infants, 6 in low birth weight infants, and 7 in children with chronic health conditions. Estimates of coverage in these populations were highly variable, ranging from 40% to 100% across the vaccines and population groups.

Conclusions

There is a lack of studies reporting coverage and timeliness of routine immunizations in special populations of children.

Policy implications

Our review suggests a need for improved surveillance of immunization status in special populations of infants, as well as a need for standardization of reporting practices.  相似文献   
8.
Objective: To assess the quality of images and video clips of fetal central nervous (CNS) structures obtained by ultrasound and transmitted via tele-ultrasound from Brazil to Australia.

Methods: In this cross-sectional study, 15 normal singleton pregnant women between 20 and 26 weeks were selected. Fetal CNS structures were obtained by images and video clips. The exams were transmitted in real-time using a broadband internet and an inexpensive video streaming device. Four blinded examiners evaluated the quality of the exams using the Likert scale. We calculated the mean, standard deviation, mean difference, and p values were obtained from paired t tests.

Results: The quality of the original video clips was slightly better than that observed by the transmitted video clips; mean difference considering all observers = 0.23 points. In 47/60 comparisons (78.3%; 95% CI?=?66.4–86.9%) the quality of the video clips were judged to be the same. In 182/240 still images (75.8%; 95% CI?=?70.0–80.8%) the scores of transmitted image were considered the same as the original.

Conclusion: We demonstrated that long distance tele-ultrasound transmission of fetal CNS structures using an inexpensive video streaming device provided images of subjective good quality.  相似文献   
9.
10.
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