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   26258篇
  免费   1358篇
  国内免费   252篇
耳鼻咽喉   213篇
儿科学   530篇
妇产科学   626篇
基础医学   2764篇
口腔科学   527篇
临床医学   2288篇
内科学   7661篇
皮肤病学   570篇
神经病学   2310篇
特种医学   912篇
外科学   4339篇
综合类   62篇
一般理论   5篇
预防医学   915篇
眼科学   350篇
药学   1385篇
中国医学   44篇
肿瘤学   2367篇
  2024年   18篇
  2023年   213篇
  2022年   163篇
  2021年   776篇
  2020年   490篇
  2019年   651篇
  2018年   769篇
  2017年   590篇
  2016年   735篇
  2015年   791篇
  2014年   1006篇
  2013年   1391篇
  2012年   2138篇
  2011年   2103篇
  2010年   1232篇
  2009年   1099篇
  2008年   1928篇
  2007年   1821篇
  2006年   1664篇
  2005年   1676篇
  2004年   1528篇
  2003年   1357篇
  2002年   1249篇
  2001年   167篇
  2000年   116篇
  1999年   171篇
  1998年   222篇
  1997年   202篇
  1996年   157篇
  1995年   184篇
  1994年   152篇
  1993年   136篇
  1992年   88篇
  1991年   76篇
  1990年   89篇
  1989年   53篇
  1988年   47篇
  1987年   39篇
  1986年   53篇
  1985年   51篇
  1984年   58篇
  1983年   41篇
  1982年   51篇
  1981年   32篇
  1980年   43篇
  1979年   26篇
  1978年   16篇
  1977年   18篇
  1975年   24篇
  1974年   20篇
排序方式: 共有10000条查询结果,搜索用时 211 毫秒
11.
12.
13.
14.
15.
16.
The main purpose of this study was to assess whether it is possible to improve the prognostic impact of international prognostic index (IPI) score by combining it with peripheral blood counts. Thus, we evaluated the prognostic power of lymphocyte, neutrophil, and monocyte counts in 520 patients with diffuse large B cell lymphoma treated with R-CHOP, confirming that these parameters have a strong impact on overall survival (OS). Using revised IPI (R-IPI), 44% of patients were categorized as poor-risk and showed an OS at 5 years of 46%. As OS at 5 years of the 520 patients is 67%, it is clearly evident that R-IPI tends to overestimate the proportion of patients with poor prognosis. Accordingly, in an attempt to improve the discriminating power of R-IPI, we evaluated and compared three different scores by combining the neutrophil lymphocyte ratio (NLR) and absolute monocyte count (AMC) with the following values: (a) IPI score 3-5, (b) age > 60 years and performance status, (c) age ≥ 65 years and LDH > ULN. The three indexes studied, had a similar 5 years OS for the high-risk group (46%-52%), but the proportion of patients classified as poor-risk were 37%, 20%, and 32%, respectively, which are lower than 44% identified with R-IPI. Thus, while R-IPI overestimates the number of high-risk patients, after applying our models, it is possible to recognize patients who are truly at high-risk. Of the three scores, the most accurate appears to be that based on NLR, AMC, LDH > ULN and age ≥ 65 years, which identifies 32% of high-risk patients, correlating well with what is seen in clinical practice.  相似文献   
17.
18.
19.
ABSTRACT

Introduction: Steroid hormones are responsible for specific changes in the endometrium during the menstrual cycle, when they are sequentially secreted and, because of this, in the early days sequential combined oral contraceptive regimens were utilized. The same basic concept has been utilized with multi-phasic regimens, in order to produce endometrial pictures mimicking the normal cycle.

Areas covered: The Endometrial effects of progestins and estrogens; combined monophasic high- (50 μg), medium- (30 μg), low- (20 μg), ultralow- (15 μg) estrogen content; sequential regimens; multiphasic combinations; treatment schedules.

Cervical effects of combined high-dose and sequential combinations, including evidence for an increase in malignant lesions.

Expert opinion: Overall, combined oral contraceptives (COCs) inhibit normal proliferative changes and the endometrium becomes thin, narrow, with widely spaced glands and pre-decidual changes in the stroma. During the first few cycles the progestin induces a coexistence of proliferative and secretory features; with time, the picture changes because the progestin induces a down-regulation of estrogen receptors, resulting in tortuous glands similar to those in the secretory phase, but characterized by a quiescent, atrophic glandular epithelium.

In the cervical epithelium, under the influence of high-dose COCs, endocervical glands became hypersecretory and in some instances, distinctive type of atypical polypoid endocervical hyperplasia is found.  相似文献   
20.

Background

Total ankle replacement (TAR) represents an alternative to fusion for the treatment of end-stage ankle osteoarthritis. The aim of the present study was to retrospectively assess the frequency of infections between TARs with anterior and lateral transfibular approach at 12-months follow-up.

Methods

81 TARs through an anterior approach and 69 TARs through a lateral approach were performed between May 2011 and July 2015. We compared surgical time and tourniquet time, as well as superficial and deep infections frequency during the first 12 postoperative months.

Results

In the anterior approach group, there were 3 (3.7%) deep infections and 4 (4.9%) superficial wound infections. In the lateral approach group, there were 1 (1.4%) deep infection and 2 superficial wound infections (2.9%). There were not statistically significant differences between the groups. There was a significant difference between anterior approach (115 minutes) and lateral approach group (179 minutes) in terms of surgical time (P < 0.001).

Conclusions

The frequency of superficial and deep periprosthetic infections during the first postoperative year was not significantly different in the lateral approach group compared to the anterior approach group, despite the significantly longer surgical time in the lateral transfibular approach group.  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