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   7499篇
  免费   405篇
  国内免费   44篇
耳鼻咽喉   81篇
儿科学   188篇
妇产科学   180篇
基础医学   1081篇
口腔科学   321篇
临床医学   608篇
内科学   1296篇
皮肤病学   116篇
神经病学   751篇
特种医学   507篇
外科学   1120篇
综合类   34篇
一般理论   2篇
预防医学   392篇
眼科学   204篇
药学   524篇
中国医学   14篇
肿瘤学   529篇
  2023年   42篇
  2022年   113篇
  2021年   206篇
  2020年   146篇
  2019年   169篇
  2018年   178篇
  2017年   166篇
  2016年   222篇
  2015年   252篇
  2014年   310篇
  2013年   454篇
  2012年   583篇
  2011年   576篇
  2010年   347篇
  2009年   307篇
  2008年   504篇
  2007年   493篇
  2006年   437篇
  2005年   415篇
  2004年   358篇
  2003年   350篇
  2002年   335篇
  2001年   62篇
  2000年   42篇
  1999年   57篇
  1998年   53篇
  1997年   39篇
  1996年   54篇
  1995年   50篇
  1994年   41篇
  1993年   28篇
  1992年   30篇
  1991年   23篇
  1990年   15篇
  1989年   21篇
  1988年   17篇
  1987年   27篇
  1986年   22篇
  1985年   30篇
  1984年   28篇
  1983年   21篇
  1982年   26篇
  1981年   17篇
  1980年   18篇
  1979年   14篇
  1978年   16篇
  1977年   16篇
  1974年   18篇
  1971年   13篇
  1967年   17篇
排序方式: 共有7948条查询结果,搜索用时 15 毫秒
91.
92.

Background

The right ventricular ejection fraction (RVEF) is a surrogate marker of right ventricular function in pulmonary hypertension (PH), but its measurement is complicated and time consuming. The tricuspid annular plane systolic excursion (TAPSE) measures only the longitudinal component of RV contraction while the right ventricular fractional area change (RVFAC) takes into account both the longitudinal and the transversal components. The aim of our study was to evaluate the relationship between RVEF, RVFAC, and TAPSE according to hemodynamic severity in two groups of patients with PH: pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH).

Methods and Results

Fifty-four patients with PAH (n?=?15) and CTEPH (n?=?39) underwent right heart catheterization and cardiac magnetic resonance (CMR). The ventricular volumes and areas, TAPSE, and eccentricity index were measured. The RVFAC was more strongly correlated with the RVEF (r?=?0.81, p?<?0.0001) than the TAPSE (r?=?0.63, p?<?0.0001). RVEF?<?35% was better predicted by the RVFAC than the TAPSE (TAPSE: AUC?=?0.77 and RVFAC: AUC?=?0.91; p?=?0.042). In the group with the worse hemodynamic status, the RVFAC correlated much better with the RVEF than the TAPSE. There were no significant differences in the CMR data analyzed between the groups of PAH and CETPH patients.

Conclusions

The RVFAC is a good index to estimate RVEF in PH patients; even better than the TAPSE in patients with more severe hemodynamic profile, possibly for including the transversal component of right ventricular function in its measurement. Furthermore, RVFAC performance was similar in the two PH groups (PAH and CTEPH).
  相似文献   
93.
94.
The aim of our study is to investigate whether single-nucleotide dystrophin gene (DMD) variants associate with variability in cognitive functions in healthy populations. The study included 1240 participants from the Erasmus Rucphen family (ERF) study and 1464 individuals from the Rotterdam Study (RS). The participants whose exomes were sequenced and who were assessed for various cognitive traits were included in the analysis. To determine the association between DMD variants and cognitive ability, linear (mixed) modeling with adjustment for age, sex and education was used. Moreover, Sequence Kernel Association Test (SKAT) was used to test the overall association of the rare genetic variants present in the DMD with cognitive traits. Although no DMD variant surpassed the prespecified significance threshold (P<1 × 10−4), rs147546024:A>G showed strong association (β=1.786, P-value=2.56 × 10−4) with block-design test in the ERF study, while another variant rs1800273:G>A showed suggestive association (β=−0.465, P-value=0.002) with Mini-Mental State Examination test in the RS. Both variants are highly conserved, although rs147546024:A>G is an intronic variant, whereas rs1800273:G>A is a missense variant in the DMD which has a predicted damaging effect on the protein. Further gene-based analysis of DMD revealed suggestive association (P-values=0.087 and 0.074) with general cognitive ability in both cohorts. In conclusion, both single variant and gene-based analyses suggest the existence of variants in the DMD which may affect cognitive functioning in the general populations.  相似文献   
95.
96.
97.
98.
99.

After the use of thallium as rat poison was banned, the knowledge about the severe and treacherous course of poisonings with this toxic metal has widely been lost. In the present case, the male victim sustained two insidious poisoning attacks in 2017 and 2020 by the perpetrator, his female life partner. In the first poisoning episode, he suffered from increasing heavy pain of the abdomen, stinging pain of both legs, persistent obstipation, hyperesthesia, and, after about 2 weeks, tuft-wise loss of hair as typical symptoms of the thallium poisoning. Within 7 weeks, he was successively examined in six hospitals with a wide variety of diagnostic methods, but a conclusive explanation of the complaints was not found. The possibility of a metal intoxication was then suggested by the perpetrator who privately arranged the analysis of a blood sample with the result of 175 µg/l thallium. Although a criminal poisoning was assumed, the perpetrator was not identified. After the victim left the perpetrator, she subtly executed a second poisoning attack with thallium sulfate (blood level 1230 µg/l after 1 day, urine level 4760 µg/l after 10 days, and hair concentrations 3.26–0.49 from proximal to distal in 9 segments). The perpetrator was sentenced to 10.5 years imprisonment for grievous bodily harm and attempted murder. Because of the behavior of the perpetrator, a Munchausen by proxy syndrome was discussed as a motivation of the first poisoning but was excluded by the psychiatric expert because of a missing antisocial personality disorder.

  相似文献   
100.
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