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   1334篇
  免费   54篇
  国内免费   13篇
耳鼻咽喉   54篇
儿科学   107篇
妇产科学   90篇
基础医学   75篇
口腔科学   35篇
临床医学   78篇
内科学   287篇
皮肤病学   39篇
神经病学   99篇
特种医学   20篇
外科学   338篇
综合类   16篇
预防医学   32篇
眼科学   23篇
药学   75篇
中国医学   9篇
肿瘤学   24篇
  2024年   1篇
  2023年   12篇
  2022年   16篇
  2021年   36篇
  2020年   17篇
  2019年   28篇
  2018年   35篇
  2017年   25篇
  2016年   42篇
  2015年   53篇
  2014年   56篇
  2013年   66篇
  2012年   90篇
  2011年   89篇
  2010年   57篇
  2009年   55篇
  2008年   89篇
  2007年   95篇
  2006年   113篇
  2005年   98篇
  2004年   94篇
  2003年   73篇
  2002年   80篇
  2001年   17篇
  2000年   11篇
  1999年   8篇
  1998年   3篇
  1997年   7篇
  1996年   10篇
  1995年   10篇
  1994年   7篇
  1989年   1篇
  1988年   1篇
  1985年   2篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
  1959年   1篇
排序方式: 共有1401条查询结果,搜索用时 0 毫秒
61.
Thrombocytopenia and absent radii (TAR) syndrome is a rare disorder. It may be associated with, for example, as cardiovascular, genitourinary, gastrointestinal, skeletal, neurological, ophthalmic, and facial anomalies. Esophageal atresia is also a rare anomaly associated with genitourinary, skeletal, and cardiovascular anomalies, among others. Here, the authors present a child with TAR syndrome and esophageal atresia with tracheoesophageal fistula. This association has been reported in only one other case in literature.  相似文献   
62.
63.
OBJECTIVE: To assess whether a relationship existed between the T102C polymorphism of 5-HT2A receptor gene and temporomandibular dysfunction. METHODS: Sixty-three patients with temporomandibular dysfunction, and 54 healthy volunteer controls were included in the study. Molecular analysis of the T102C polymorphism of the 5-HT2A receptor gene was performed using PCR technique. RESULTS: The C/C genotype was over represented in the patients whereas T/T genotype was over represented in the controls (P < 0.05). The genotype distribution of the patients who had temporomandibular dysfunction was not different than those who did not have temporomandibular dysfunction (P > 0.05). CONCLUSION: The T102C polymorphism may be involved in the etiology of temporomandibular dysfunction. The overrepresentation of the C/C variant of 5-HT2A receptor gene in temporomandibular dysfunction suggests a possible role of the serotonergic system in this disease, particularly at the receptor level.  相似文献   
64.
65.
OBJECTIVES: To determine the effects of 'coasting' on the outcome of controlled ovarian hyperstimulation (COH) and intracytoplasmic sperm injection-embryo transfer (ICSI-ET). DESIGN: Retrospective study. SETTING: IVF Centre, Ozel Ege Tup Bebek Merkezi, Izmir, Turkey. SAMPLE: Twenty-six coasted and 52 non-coasted COH and ICSI-ET patients were enrolled in this retrospective study. METHODS: Coasted patients were enrolled consecutively during the study period, and two non-coasted controls were selected from our database for each coasted patient. Coasting was decided when serum oestradiol level was > or = 4000 pg/mL. Groups were compared using chi2 and Mann-Whitney U-tests for statistical analysis. MAIN OUTCOME MEASURES: Number of oocytes collected, metaphase II (MII) oocytes and cleaving embryos, the fertilisation rate and clinical pregnancy rate were the main outcome measures. RESULTS: Number of oocytes collected, number of MII oocytes, number of cleaving embryos, fertilisation rate and clinical pregnancy rate for the coasted and non-coasted groups were 15.5 +/- 5.2 and 14.0 +/- 7.1, 9.7 +/- 4.8 and 9.3 +/- 3.9, 6.8 +/- 3.9 and 5.8 +/- 3.1, 0.85 +/- 0.18 and 0.78 +/- 0.18, 13/26 and 24/52, respectively; these differences were not statistically significant. None of the patients in the coasted group were hospitalised for signs or findings of severe ovarian hyperstimulation syndrome. CONCLUSIONS: Coasting does not adversely affect the number and the function of mature oocytes and the clinical pregnancy rate.  相似文献   
66.
The effect of mid-luteal estradiol level on the outcome of ICSI-ET cycles   总被引:3,自引:0,他引:3  
Methods We investigated if mid-luteal estradiol levels could predict the outcome in intracytoplasmic sperm injection embryo transfer (ICSI-ET) cycles (n=231). Pregnant and non-pregnant women were compared regarding their peak estradiol levels on human chorionic gonadotropin (hCG) injection day, and mid-luteal estradiol levels on the 7th day following oocyte recovery. Pregnancy rates of the groups that were designed according to the "peak/mid-luteal estradiol level" and the mid-luteal estradiol levels were also compared.Results Peak and mid-luteal estradiol levels in pregnant women were higher than in non-pregnant women in all patients, although the difference between peak and mid-luteal estradiol levels were similar in pregnant and non-pregnants. Pregnant women had higher mid-luteal estradiol levels in good responders, but the peak estradiol levels of pregnant and non-pregnant women were similar. In poor responders, pregnant and non-pregnant women were similar with respect to peak and mid-luteal estradiol levels. Both in all patients and good responders, women with mid-luteal estradiol levels <200 pg/ml had lower pregnancy rates than those with >2,000 pg/ml. Peak/mid-luteal estradiol ratios of pregnant and non-pregnant women were not significantly different in all patients, good responders and poor responders; although a tendency for a lower ratio in pregnants was encountered in good responders. Pregnancy rates of the groups according to the "peak/mid-luteal estradiol ratio" were similar; in all patients, good responders and poor responders.Conclusion A relation between the mid-luteal estradiol level and the outcome is encountered only in good responders.  相似文献   
67.
Acrocallosal syndrome is characterized by agenesis of the corpus callosum, craniofacial anomalies, psychomotor retardation, and polydactyly. The clinical spectrum of this syndrome is broader than previous reports suggest. Five Turkish patients including dizygotic twins are reported.  相似文献   
68.
BACKGROUND/AIMS: The aim of this study was to evaluate the predictive accuracy of P-POSSUM and O-POSSUM models on patients undergoing elective gastric resection. METHODOLOGY: P-POSSUM and O-POSSUM predictor equations for mortality were applied retrospectively to 126 patients who had undergone elective gastrectomy for cancer. Observed mortality rates were compared with rates predicted by P-POSSUM and O-POSSUM using the Hosmer-Lemeshow goodness-of-fit test. Evaluation of the discriminative capability of both models was performed using receiver-operating characteristic (ROC) curve analysis. RESULTS: Overall fourteen deaths were observed. O-POSSUM predicted 15 deaths (chi2=14.61, p=0.13) and P-POSSUM predicted 20 deaths (chi2=25.41, p=0.002) using the Hosmer-Lemeshow test. ROC curves analysis revealed that O-POSSUM had better discriminatory power for mortality compared to P-POSSUM (area under curve=0.880, for O-POSSUM and area under curve=0.703 for P-POSSUM). CONCLUSIONS: These data suggest that O-POSSUM predicts mortality more accurately than P-POSSUM in patients undergoing elective gastrectomy for cancer.  相似文献   
69.
Measurement of ionized magnesium (IMg) provides an accurate assessment of the free form of Mg, which is the physiologically active form and is most reflective of the biologically active and not easily measurable intracellular Mg fraction. Plasma levels of IMg were measured by ion-selective electrode method in premature newborns with respiratory distress syndrome (RDS), and relationships and correlations between IMg levels and various demographic, prognostic and laboratory characteristics were investigated by comparing the premature newborns with (study group; n = 19) and without RDS (control group; n = 20) in the present study. The values of the postnatal arterial pH and base excess and plasma IMg levels were significantly different between the study and control groups, and the number of newborns with any morbidity was significantly higher in the study group. Within the study group there were significant negative correlations between the plasma IMg levels and the values of the umbilical cord arterial pH (r = -0.621, p = 0.005) and base excess (r = -0.746, p = 0.001), and the value of the postnatal arterial base excess (r = -0.585, p = 0.008). The newborns who died later had higher plasma IMg levels than those who survived (0.89 +/- 0.45 vs. 0.63 +/- 0.24 mmol/l, p = 0.026). These findings suggest that increase of plasma IMg may be due to extracellular movement of Mg, which is a principally intracellular ion, as a result of acidosis, hypoxia and probable cellular injury during the early course of RDS. The exact pathophysiological mechanism responsible for IMg increase, and whether determination of plasma IMg level, including umbilical cord blood IMg measurement, can be used as an early or predictive indicator of RDS in the diagnosis remain to be determined in further large-scale studies.  相似文献   
70.
Inhibition of human cytochromes P450 by components of Ginkgo biloba   总被引:3,自引:0,他引:3  
The extraction, isolation and characterization of 29 natural products contained in Ginkgo biloba have been described, which we have now tested for their in-vitro capacity to inhibit the five major human cytochrome P450 (CYP) isoforms in human liver microsomes. Weak or negligible inhibitory activity was found for the terpene trilactones (ginkgolides A, B, C and J, and bilobalide), and the flavonol glycosides. However 50% inhibitory activity (IC50) was found at concentrations less than 10 microg L(-1) for the flavonol aglycones (kaempferol, quercetin, apigenin, myricetin, tamarixetin) with CYP1A2 and CYP3A. Quercetin, the biflavone amentoflavone, sesamin, as well as (Z,Z)-4,4'-(1,4-pentadiene-1,5-diyl)diphenol and 3-nonadec-8-enyl-benzene-1,2-diol, were also inhibitors of CYP2C9. The IC50 of amentoflavone for CYP2C9 was 0.019 microg mL(-1) (0.035 microM). Thus, the principal components of Ginkgo biloba preparations in clinical use (terpene trilactones and flavonol glycosides) do not significantly inhibit these human CYPs in-vitro. However, flavonol aglycones, the biflavonol amentoflavone and several other non-glycosidic constituents are significant in-vitro inhibitors of CYP. The clinical importance of these potential inhibitors will depend on their amounts in ginkgo preparations sold to the public, and the extent to which their bioavailability allows them to reach the CYP enzymes in-situ.  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