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   779篇
  免费   48篇
  国内免费   7篇
耳鼻咽喉   15篇
儿科学   59篇
妇产科学   59篇
基础医学   100篇
口腔科学   18篇
临床医学   63篇
内科学   127篇
皮肤病学   12篇
神经病学   158篇
特种医学   17篇
外科学   42篇
综合类   5篇
一般理论   1篇
预防医学   50篇
眼科学   11篇
药学   44篇
中国医学   3篇
肿瘤学   50篇
  2023年   5篇
  2022年   12篇
  2021年   29篇
  2020年   18篇
  2019年   28篇
  2018年   36篇
  2017年   33篇
  2016年   31篇
  2015年   27篇
  2014年   28篇
  2013年   44篇
  2012年   59篇
  2011年   75篇
  2010年   46篇
  2009年   36篇
  2008年   50篇
  2007年   53篇
  2006年   44篇
  2005年   42篇
  2004年   33篇
  2003年   34篇
  2002年   23篇
  2001年   3篇
  2000年   2篇
  1999年   1篇
  1998年   5篇
  1997年   7篇
  1993年   3篇
  1992年   1篇
  1987年   2篇
  1986年   3篇
  1985年   1篇
  1983年   1篇
  1980年   1篇
  1979年   1篇
  1977年   4篇
  1976年   2篇
  1975年   4篇
  1974年   2篇
  1972年   2篇
  1971年   1篇
  1969年   1篇
  1965年   1篇
排序方式: 共有834条查询结果,搜索用时 0 毫秒
31.
Aim: To evaluate the performance of exchange transfusion in very low birth weight (VLBW) infants with excessively high serum bilirubin levels. Methods: A population‐based observational study using data collected by the Israel National VLBW Infant Database. The study sample comprised 13 499 infants. Two definitions of excessively high‐peak bilirubin levels that might be considered as threshold levels for performance of exchange transfusion were used. First, a bilirubin level of ≥15 mg/dL for all infants (PSB‐15), and second, incremental bilirubin levels ranging from 12 to 17 mg/dL according to gestational age (PSB‐GA). Results: Four hundreds sixty‐eight (3.5%) and 1035 infants (7.7%) infants in the PSB‐15 and in the PSB‐GA groups respectively had peak serum bilirubin levels above thresholds for exchange transfusion. Exchange transfusions were performed in 66 (14.1%) of these infants in the PSB‐15 group and 91 (8.8%) in the PSB‐GA group. Using logistic regression analysis, peak serum bilirubin was found as an independent factor for performing exchange transfusion. Conclusion: Exchange transfusion was performed in only 9–14% of VLBW infants with excessively high bilirubin levels. We speculate that this may be a result of an absence of definitive guidelines or the possible belief that the risks of exchange transfusion outweigh the potential risk of bilirubin‐induced neurological injuries.  相似文献   
32.
Objective: Evaluate physiologic factors associated with reduced maternal perception of fetal movements (RFM).

Methods: A historical cohort study of all women (years 2011–2013, n?=?399) that visited the maternal emergency room (ER) (gestational age 24?+?0–42?+?0) due to RFM (group A), that was compared to a control group consisted from women with normal perception of fetal movements (group B). Groups were compared for maternal characteristics (age, gravity, parity, BMI), gestational age, placental location, gestational age at birth and fetal outcomes (birth-weight and Apgar scores).

Results: In a multivariate regression analysis, including maternal age, height, weight, BMI, gestational age on admission to ER, gravity, parity and placental location, only two variables remained significantly associated with RFM – nulliparity (OR?=?2.28, p?=?0.001) and anterior placenta (OR?=?1.44, p?=?0.034). Group A was not associated with lower Apgar scores (1 and 5-min, p?=?0.40 and 0.57, respectively) or low birth-weight (p?=?0.76), nor was it associated with prematurity (p?=?0.41), low (<7) 5-min Apgar score, fetal death or neonatal death.

Conclusions: Reduced fetal movements are associated with anterior placenta and nulliparity.  相似文献   
33.
PROBLEM: The present study aimed at investigating the presence of Interleukin-10 (IL-10) in preovulatory follicular fluid (FF) and its possible correlation with 17-β-estradiol (E2) and progesterone (P) levels, and treatment outcome in patients undergoing in-vitro fertilization-embryo transfer (IVF-ET). METHODS: Twenty consecutive patients with tubal factor infertility who underwent oocyte retrieval for IVF-ET were assayed for pooled, preovulatory FF levels of IL-10, E2, and P. RESULTS: The mean FF levels of IL-10, E2, and P were 78.7 ± 104.7 pg/ml, 2,787.0 ± 726.1 pg/ml, and 1.5 ± 0.8 ng/ml, respectively. No correlation was found between preovulatory FF concentration of IL-10, E2, oocyte number, oocyte fertilization rate, embryo quality, and pregnancy rate. The levels of IL-10 were found to be negatively correlated with P concentration, although not significantly (P = 0.057). CONCLUSION: Interleukin-10 exists in the preovulatory FF. Further investigations are needed to determine the role of IL-10 in the folliculogenesis.  相似文献   
34.
35.
36.
The study examined differences in division of household tasks and spousal support among a sample of educated dual‐earner families from two national groups in Israel: Jews (n = 116), and Arabs (n = 163). The contribution of the spousal interaction variables (household roles and spousal support) toward explaining two dimensions of psychological well‐being (burnout and life satisfaction) was also examined. The research findings indicate that in general, the Arabs maintain a more traditional orientation toward gender roles than their Jewish counterparts. Arab men showed a greater tendency to perform outside tasks than their Jewish counterparts who participate more in domestic chores. By contrast, no differences were found between the two groups with regard to the mutual support provided by spouses. Gender role attitudes were found to be a key predictor of the two psychological well‐being dimensions in both national groups. Regarding sex differences, men of both nationalities were more likely than women to report that they perform all types of household tasks. Concomitantly, the women reported higher levels of burnout, while no differences between the sexes were found with respect to life satisfaction. © 2003 Wiley Periodicals, Inc.  相似文献   
37.
Collagen, fibrin and albumin are popular proteins for making biological scaffolds for tissue engineering because of their biocompatibility, biodegradability, and availability. A major drawback of biological protein-based biomaterials is the limited control over their physical and biodegradation properties. Our laboratory has been developing new protein-based biomaterials with tunable properties without the use of cytotoxic protein cross-linking techniques. We describe the formation and assembly of photopolymerizable biomimetic hydrogel scaffolds made from protein-polymer conjugates of poly(ethylene glycol) (PEG) and collagen, fibrin or albumin. The conjugation of PEG to these proteins (PEGylation) was verified by SDS-PAGE and the polymerization reaction into a hydrogel network was confirmed by shear rheometry. The differences in rheology and swelling characteristics of the three hydrogel materials underscore the importance of the molecular relationship between the PEG and the protein constituent in this protein-polymer arrangement. The biofunctionality of the PEGylated collagen and fibrinogen hydrogels sustained both cell adhesion and proteolytic degradation that enabled 3-D cell spreading and migration within the hydrogel network. PEG-albumin hydrogels exhibited poor cell spreading and migration by virtue of the fact that the albumin backbone lacks any known cell adhesion sites. Despite differences in the biological and structural composition of the PEGylated fibrinogen and collagen hydrogels, the rate of cellular migration within each material was not significantly different.  相似文献   
38.

Introduction  

Splenic metastasis from endometrial carcinoma is a rare clinical event, with only 11 cases documented previously in the literature.  相似文献   
39.
PURPOSE: The Met receptor tyrosine kinase and its ligand, hepatocyte growth factor/scatter factor (HGF/SF), are involved in a wide range of biological activities, including cell proliferation, motility, invasion, and angiogenesis. The HGF/SF-Met signaling pathway is frequently activated in a variety of cancers, and uncontrolled Met activation correlates with highly invasive tumors and poor prognosis. In this study, we investigated the inhibitory effect of a novel soluble splice variant of Met on the HGF/SF-Met pathway. EXPERIMENTAL DESIGN: Using our alternative splicing modeling platform LEADS, we have identified a novel splice variant of the Met receptor, which encodes a truncated soluble form of the receptor. This variant was produced as a recombinant Fc-fused protein named Cgen-241A and was tested in various cell-based assays representing different outcomes of the HGF/SF-Met pathway. RESULTS: Cgen-241A significantly inhibited HGF/SF-induced Met phosphorylation as well as cell proliferation and survival. In addition, Cgen-241A showed a profound inhibitory effect on cell scattering, invasion, and urokinase up-regulation. The inhibitory effects of Cgen-241A were shown in multiple human and nonhuman cell types, representing different modes of Met activation. Furthermore, Cgen-241A showed direct binding to HGF/SF. CONCLUSIONS: Taken together, our results indicate that Cgen-241A is a potent antagonist of the HGF/SF-Met pathway, underlining its potential as a therapeutic agent for the treatment of a wide variety of human malignancies that are dependent on this pathway.  相似文献   
40.
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