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   84600篇
  免费   5662篇
  国内免费   2132篇
耳鼻咽喉   478篇
儿科学   1216篇
妇产科学   730篇
基础医学   10285篇
口腔科学   1355篇
临床医学   6238篇
内科学   10100篇
皮肤病学   1708篇
神经病学   6630篇
特种医学   1650篇
外国民族医学   9篇
外科学   7138篇
综合类   10554篇
现状与发展   5篇
预防医学   6011篇
眼科学   871篇
药学   15936篇
  9篇
中国医学   4236篇
肿瘤学   7235篇
  2023年   1081篇
  2022年   1617篇
  2021年   2752篇
  2020年   1963篇
  2019年   4772篇
  2018年   4277篇
  2017年   3028篇
  2016年   2142篇
  2015年   2624篇
  2014年   4864篇
  2013年   4974篇
  2012年   4124篇
  2011年   4717篇
  2010年   4276篇
  2009年   4657篇
  2008年   3872篇
  2007年   4563篇
  2006年   4085篇
  2005年   3293篇
  2004年   2303篇
  2003年   2269篇
  2002年   1719篇
  2001年   1399篇
  2000年   1376篇
  1999年   1122篇
  1998年   1106篇
  1997年   982篇
  1996年   880篇
  1995年   808篇
  1994年   704篇
  1993年   607篇
  1992年   596篇
  1991年   532篇
  1990年   441篇
  1989年   411篇
  1988年   329篇
  1987年   359篇
  1986年   359篇
  1985年   867篇
  1984年   1000篇
  1983年   657篇
  1982年   705篇
  1981年   607篇
  1980年   567篇
  1979年   453篇
  1978年   343篇
  1977年   265篇
  1976年   236篇
  1975年   185篇
  1974年   169篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.

Background

Controversy continues as to whether single-incision laparoscopic cholecystectomy, with the somewhat larger incision at the umbilicus, may lead to a worse postoperative quality of life and more pain compared with the more classic 4-port laparoscopic cholecystectomy. The aim of this study was to compare single-incision and 4-port laparoscopic cholecystectomy from the perspective of quality of life.

Methods

This study was a multicenter, parallel-group, open-label, randomized clinical trial. A total of 120 patients who were scheduled to undergo elective cholecystectomy were randomly assigned 1:1 into the single-incision laparoscopic cholecystectomy or the 4-port laparoscopic cholecystectomy group and then assessed continuously for 2 weeks during the postoperative period. The primary outcome was quality of life, defined as the time to resume normal daily activities. Postoperative pain was also assessed. To explore the heterogeneity of treatment effects, we assessed the interactions of sex, age, and working status on recovery time.

Results

A total of 58 patients in the single-incision group and 53 in the 4-port group (n?=?111, 47 male, mean age 57 years) were analyzed. The mean time to resume daily activities was 10.2 days and 8.8 days, respectively, for single-incision and 4-port laparoscopic cholecystectomy (95% confidence interval –0.4 to 3.2, P?=?.12). Similarly, the time to relief from postoperative pain did not differ significantly between the groups. Statistically insignificant but qualitative interactions were noted; in the subgroups of women, full-time workers, and patients younger than 60 years, recovery tended to be slower after single-incision laparoscopic cholecystectomy.

Conclusion

Postoperative quality of life did not differ substantially between single-incision laparoscopic cholecystectomy and 4-port laparoscopic cholecystectomy. Patients younger than 60 years, women, and full-time workers tended to have a somewhat slower recovery after single-incision laparoscopic cholecystectomy.  相似文献   
93.
目的探讨重睑术中采用经重睑切口的上睑旋转皮瓣矫正轻、中度内眦赘皮的疗效。方法回顾分析 2016 年 7 月—2017 年 10 月,重睑术中采用经重睑切口的上睑旋转皮瓣矫正轻、中度睑板型内眦赘皮合并单睑的 34 例患者(试验组)临床资料;以同期 38 例接受传统“Z”成形内眦开大术联合重睑术患者为对照(对照组)。两组患者年龄及内侧赘皮分度比较,差异无统计学意义(P>0.05)。于术前及术后 6 d、6 个月测量眼裂长度,计算眼裂长度改善程度;参照内眦赘皮矫正标准评价手术疗效。 结果两组患者切口均Ⅰ期愈合,并获随访 6 个月。两组内眦赘皮明显矫正。试验组内眦处无切口;对照组遗留瘢痕,其中 6 例增生明显。术后 6 d 试验组及对照组眼裂长度改善程度分别为 3.63%±0.07%、3.70%±0.05%;术后 6 个月分别为 4.64%±0.09%、4.46%±0.10%;两组比较差异均无统计学意义(t=0.005,P=0.996;t=0.287,P=0.871)。术后 6 个月疗效评价,试验组优 20 例、良 12 例、差 2 例,优良率 94.12%;对照组优 16 例、良 16 例、差 6 例,优良率 84.21%;差异无统计学意义(χ2=0.796,P=0.372)。 结论经重睑切口的上睑旋转皮瓣矫正轻、中度内眦赘皮手术操作简便、效果满意,内眦处无瘢痕形成。  相似文献   
94.
Sorafenib provides survival benefits in patients with advanced renal cell carcinoma (RCC), but its use is hampered by acquired drug resistance. It is important to fully clarify the molecular mechanisms of sorafenib resistance, which can help to avoid, delay or reverse drug resistance. Extracellular vesicles (EVs) can mediate intercellular communication by delivering effector molecules between cells. Here, we studied whether EVs are involved in sorafenib resistance of RCC and its possible molecular mechanisms. Using differential centrifugation, EVs were isolated from established sorafenib-resistant RCC cells (786-0 and ACHN), and EVs derived from sorafenib-resistant cells were uptaken by sensitive parental RCC cells and thus promoted drug resistance. Elevated exogenous miR-31-5p within EVs effectively downregulated MutL homolog 1 (MLH1) expression and thus promoted sorafenib resistance in vitro. Mice experiments also confirmed that miR-31-5p could mediate drug sensitivity in vivo. In addition, low expression of MLH1 was observed in sorafenib-resistant RCC cells and upregulation of MLH1 expression restored the sensitivity of resistant cell lines to sorafenib. Finally, miR-31-5p level in circulating EVs of RCC patients with progressive disease (PD) during sorafenib therapy was higher when compared to that in the pretherapy status. In conclusion, EVs shuttled miR-31-5p can transfer resistance information from sorafenib-resistant cells to sensitive cells by directly targeting MLH1, and thus magnify the drug resistance information to the whole tumor. Furthermore, miR-31-5p and MLH1 could be promising predictive biomarkers and therapeutic targets to prevent sorafenib resistance.  相似文献   
95.
BackgroundThe peripheral level of matrix metalloproteinase (MMP)-9 and polymorphism of MMP9 -1562C>T in patients with obstructive sleep apnea (OSA) remains controversial. Therefore, the aims of this systemic review and meta-analysis are to assess the MMP9 level in OSA patients and identify the relationship between MMP9 -1562C>T and OSA susceptibility.MethodsThis systematic review was performed following the PRISMA guideline. We searched for studies in major databases, identifying those indexed from inception to July 3, 2019 which related to MMP9 level, MMP9 -1562C>T and OSA. The pooled standardized mean differences (SMDs) and 95% confidence interval (CI) of MMP9 levels were calculated. In addition, the relationship between MMP9 -1562C>T and OSA susceptibility was assessed by three genetic models. The heterogeneity analysis and calculation of the pooled odds ratio (OR) were also performed, followed by quality assessment using the Newcastle-Ottawa Scale (NOS).ResultsIn sum, our review included 15 eligible studies regarding MMP9 level and three regarding MMP9 -1562C>T. The pooled results showed that peripheral level of MMP9 was increased in OSA patients (SMD = 1.37; 95% CI = 1.15–1.59). Furthermore, significant difference of MMP9 level can be found between severe and mild-to-moderate OSA patients (SMD = 28.17; 95% CI = 4.23–52.11) or between moderate-severe and mild OSA (SMD = 36.62; 95% CI = 12.19–61.04). However, no relationship was observed between MMP9 -1562C>T and OSA susceptibility in three genetic models (Homozygote model, OR = 1.37; 95% CI = 0.87–2.18); (Recessive model, OR = 1.42; 95% CI = 0.83–2.42); (Allele model, OR = 1.07; 95% CI = 0.96–1.18).ConclusionsThis systemic review and meta-analysis indicated that the level of MMP9 was increased in patients with OSA and this increase is relevant to OSA severity. Moreover, the relationship between MMP9 -1562 C>T and OSA susceptibility has currently not been proven by current merging values. Further analyses with larger sample size are required to verify these associations.  相似文献   
96.
97.
98.
99.
The aim of this study was to evaluate learners’ acceptance of a webinar for continuing medical education that was instigated by the International Association of Oral and Maxillofacial Surgeons (IAOMS). A live, interactive webinar on orthognathic surgery was broadcast via the Internet. The learners’ acceptance of the webinar was evaluated using a standardized, validated questionnaire (Student Evaluation of Educational Quality, SEEQ). One hundred and fifty-three participants attended the webinar; 55 participants (46 male, nine female) completed the questionnaire. The mean age of the respondents was 41.6 ± 10.0 years. The age of male and female respondents did not differ significantly. The respondents were spread over five continents, with the highest number from Brazil. The SEEQ showed a high level of acceptance for almost all subscales. There was no statistically significant difference between male and female respondents concerning acceptance of the webinar (P = 0.614). The wide distribution of participants shows the potential for webinars as facilitators of barrier-free distribution of knowledge. The webinar was well accepted by the attendees independent of sex, specialty, and work experience. However, the sex ratio reflects the underrepresentation of women in oral and maxillofacial surgery.  相似文献   
100.

Purpose

To quantify eating disorder (ED) stability and diagnostic transition among a community-based sample of adolescents and young adult females in the United States.

Methods

Using 11 prospective assessments from 9,031 U.S. females ages 9–15 years at baseline of the Growing Up Today Study, we classified cases of the following EDs involving bingeing and purging: bulimia nervosa (BN), binge ED, purging disorder (PD), and subthreshold variants defined by less frequent (monthly vs. weekly) bingeing and purging behaviors. We measured number of years symptomatic and probability of maintaining symptoms, crossing to another diagnosis, or resolving symptoms across consecutive surveys.

Results

Study lifetime disorder prevalence was 2.1% for BN and roughly 6% each for binge ED and PD. Most cases reported symptoms during only one survey year. Twenty-six percent of cases crossed between diagnoses during follow-up. Among participants meeting full threshold diagnostic criteria, transition from BN was most prevalent, crossing most frequently from BN to PD (12.9% of BN cases). Within each disorder phenotype, 20%–40% of cases moved between subthreshold and full threshold criteria across consecutive surveys.

Conclusions

Diagnostic crossover is not rare among adolescent and young adult females with an ED. Transition patterns from BN to PD add support for considering these classifications in the same diagnostic category of disorders that involve purging. The prevalence of crossover between monthly and weekly symptom frequency suggests that a continuum or staging approach may increase utility of ED classification for prognostic and therapeutic intervention.  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