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   155271篇
  免费   7367篇
  国内免费   482篇
耳鼻咽喉   2594篇
儿科学   4651篇
妇产科学   3544篇
基础医学   20789篇
口腔科学   5573篇
临床医学   9693篇
内科学   37444篇
皮肤病学   4959篇
神经病学   12435篇
特种医学   3603篇
外国民族医学   2篇
外科学   18736篇
综合类   962篇
一般理论   43篇
预防医学   16689篇
眼科学   3340篇
药学   10801篇
中国医学   870篇
肿瘤学   6392篇
  2023年   963篇
  2022年   753篇
  2021年   4148篇
  2020年   2136篇
  2019年   3950篇
  2018年   5726篇
  2017年   3429篇
  2016年   3276篇
  2015年   3660篇
  2014年   4861篇
  2013年   7013篇
  2012年   10802篇
  2011年   11636篇
  2010年   6192篇
  2009年   4837篇
  2008年   8993篇
  2007年   9508篇
  2006年   8822篇
  2005年   8770篇
  2004年   7835篇
  2003年   7274篇
  2002年   6801篇
  2001年   4464篇
  2000年   5003篇
  1999年   3998篇
  1998年   979篇
  1997年   827篇
  1996年   728篇
  1995年   590篇
  1994年   424篇
  1993年   418篇
  1992年   1504篇
  1991年   1244篇
  1990年   1132篇
  1989年   949篇
  1988年   827篇
  1987年   755篇
  1986年   770篇
  1985年   657篇
  1984年   464篇
  1983年   398篇
  1979年   434篇
  1975年   305篇
  1974年   384篇
  1973年   387篇
  1972年   330篇
  1971年   359篇
  1970年   324篇
  1969年   348篇
  1968年   304篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
43.
44.

Objectives

To determine the incidence of incisional hernia (IH) in the extraction incision (EI) in colorectal resection for cancer. To analyze whether the location of the incision has any relationship with the incidence of hernias and whether mesh could be useful for prevention in high-risk patients.

Methods

Retrospective review of the colon and rectal surgery database from January 2015 to December 2016. Data were classified into 2 groups, transverse (TI) and midline incision (MI), and the latter was divided into 2 subgroups (mesh [MIM] and suture [MIS]). Patients were classified using the HERNIAscore. Hernias were diagnosed by clinical and/or CT examination.

Results

A total of 182 out of 210 surgical patients were included. After a median follow-up of 13.0 months, 39 IH (21.9%) were detected, 23 of which (13.4%) were in the EI; their frequency was lower in the TI group (3.4%) and in the MIM group (5.9%) than in the MIS group (29.5%; p = 0.007). The probability of developing IH in the MIS group showed an OR = 11.7 (95%CI: 3.3-42.0) compared to the TI group and 4.3 (IC 95%: 1.1-16.3) versus the MIM group.

Conclusions

The location of the incision is relevant to avoid incisional hernias. Transverse incisions should be used as the first option. When a midline incision is needed, a prophylactic mesh could be considered in high risk patients because it is safe and associated with low morbidity.  相似文献   
45.
Clinical Oral Investigations - The aim of this study was the analysis of WNT10A variants in seven families of probands with various forms of tooth agenesis and self-reported family history of...  相似文献   
46.
Background: Egyptian street youth use substances including tobacco, illicit drugs, and pharmaceutical drugs. To understand the circumstances, including adverse childhood experiences, that place adolescents at risk for engaging in substance use, we conducted in-depth interviews among a sample of Egyptian street children. Methods: From youth residing at or attending Caritas, a non-profit organization, which provides shelter and education to street youth, seven girls and twelve boys, aged 12–18 years, participated in open-ended, in-depth interviews. Results: Eight out of the 19 participants reported family history (early exposure) to substance use; and seven of them were initiated by either a family member (sibling), friend or coworker. Most of the participants reported a history of conflict with or abuse (verbal or physical) by their parents or siblings, or stressful situations at home; they used substance(s) to alleviate their stress. Few attended school, and some were forced to work and help their family. Conclusions: Among Egyptian youth, adverse childhood experiences, such as poverty, child abuse, and family substance use, challenge somewhat susceptible youths and lead them to the path of substance use and addiction. Prevention intervention should be multifaceted, culturally adaptable, and primarily targeting the social environment during childhood.  相似文献   
47.
Food-grade titanium dioxide (E171) is widely used as a food additive, and it is known that after oral consumption, E171 is translocated into the bloodstream reaching the highest titanium level at 6 h. E171 is accumulated in some organs triggering toxicity, but the effects on the blood parameters after oral consumption have been less studied. Recently, evidence shows that oral exposure to E171 induces behavioral signs of anxiety and depression. The relation between blood alterations and psychiatric disorders has been previously demonstrated. However, the oral exposure to E171 effects on alterations in blood parameters and effects linked to alterations in animal behavior has not been explored. In this short communication, we aimed to investigate the effects of E171 on specific blood parameters (hematocrit, hemoglobin, number of erythrocytes, and leukocytes) and anxiety and compulsive-like behavior in males and females orally exposed to ~5 mg/kg for 4 weeks. The results showed that E171 decreased hematocrit and hemoglobin in male but not in female mice while leukocyte and erythrocyte count remained unaltered. Oral consumption of E171 decreased the levels of anxiety-like behavior in females but not in male mice, while compulsive-like behavior was increased in both male and female mice.  相似文献   
48.
49.
Background: Most theoretical models of self-determination suggest that both environmental and personal factors influence the development of self-determination. The design and implementation of interventions must be conducted with foreknowledge of such mediating and moderating factors if the intervention is to be successful.

Methods: The purpose of this study was to examine the degree to which several personal factors and school characteristics affect and explain students’ self-determination. A total of 232 students with intellectual disability from Spain participated. Their self-determination level was assessed by the ARC-INICO Scale.

Results: Students with moderate levels of intellectual disability obtained significantly lower scores on self-determination than their peers with mild intellectual disability. There were significant differences in relation to the level of support needs and their experience with transition programs. The level of support needs was a significant predictor.

Conclusion: These findings contribute to current research in this field and practical implications were discussed.  相似文献   

50.
Abstract

Objectives: This study examined word use as an indicator of interpersonal positive reframing in daily conversations of couples coping with breast cancer and as a predictor of stress.

Design: The Electronically Activated Recorder (EAR) and Linguistic Inquiry and Word Count (LIWC) were used to examine naturally occurring word use conceptually linked to positive reframing (positive emotion, negative emotion, and cognitive processing words).

Sample: Fifty-two couples coping with breast cancer.

Methods: Couples wore the EAR, a device participants wear, that audio-recorded over one weekend (>16,000 sound files), and completed self-reports of positive reframing (COPE) and stress (Perceived Stress Scale). LIWC, a software program, measured word use.

Findings: Both partners’ word use (i.e., positive emotion and cognitive processing words) was associated with their own reported positive reframing, and spouses’ word use was also indicative of patients’ positive reframing. Results also revealed that, in general, words indicating positive reframing predicted lower levels of stress.

Conclusions: Findings supported the hypothesis that partners—and particularly spouses of breast cancer patients—may assist each other’s coping by positively reframing the cancer experience and other negative experiences in conversation.  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