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   6846篇
  免费   325篇
  国内免费   144篇
耳鼻咽喉   74篇
儿科学   102篇
妇产科学   133篇
基础医学   886篇
口腔科学   112篇
临床医学   551篇
内科学   1511篇
皮肤病学   116篇
神经病学   464篇
特种医学   670篇
外科学   876篇
综合类   75篇
预防医学   200篇
眼科学   67篇
药学   746篇
中国医学   92篇
肿瘤学   640篇
  2023年   44篇
  2022年   141篇
  2021年   223篇
  2020年   102篇
  2019年   147篇
  2018年   160篇
  2017年   143篇
  2016年   198篇
  2015年   260篇
  2014年   299篇
  2013年   350篇
  2012年   520篇
  2011年   516篇
  2010年   363篇
  2009年   253篇
  2008年   399篇
  2007年   395篇
  2006年   318篇
  2005年   313篇
  2004年   253篇
  2003年   213篇
  2002年   163篇
  2001年   161篇
  2000年   152篇
  1999年   127篇
  1998年   104篇
  1997年   98篇
  1996年   87篇
  1995年   82篇
  1994年   48篇
  1993年   53篇
  1992年   42篇
  1991年   51篇
  1990年   48篇
  1989年   74篇
  1988年   57篇
  1987年   56篇
  1986年   32篇
  1985年   41篇
  1984年   24篇
  1983年   18篇
  1982年   20篇
  1981年   24篇
  1980年   25篇
  1979年   19篇
  1978年   10篇
  1977年   17篇
  1976年   14篇
  1975年   9篇
  1969年   7篇
排序方式: 共有7315条查询结果,搜索用时 15 毫秒
71.
Objective The aim of the study was to develop a checklist for mental health clinicians to predict and manage suicidality. Methods A literature review of the risk and protective factors for suicide was conducted to develop a checklist for evaluating suicidality. Results The fixed risk factors included sex (male), age (older individuals), history of childhood adversity, and a family history of suicide. Changeable risk factors included marital status (single), economic status (poverty), physical illness, history of psychiatric hospitalization, and history of suicide attempts. Recent discharge from a mental hospital and a recent history of suicide attempts were also included. Manageable risk factors included depression (history and current), alcohol problems (frequent drinking and alcohol abuse), hopelessness, agitation, impulsivity, impaired reality testing, and command hallucinations. Protective factors included responsibility to family, social support, moral objections to suicide, religiosity, motivation to get treatment, ability to cope with stress, and a healthy lifestyle. A final score was assigned based on the sum of the risk and protective factor scores. Conclusion We believe that the development of this checklist will help mental health clinicians to better assess those at risk for suicidal behavior. Further studies are necessary to validate the checklist.  相似文献   
72.
We investigated whether dining with companions is correlated with the alleviation of depression and differs by sex among Korean adults. We used 4-year data from the 2014, 2016, 2018, and 2020 Korea National Health and Nutrition Examination Survey. We surveyed 11,055 participants (4699 men, 6356 women) using the Patient Health Questionnaire-9 to measure their depression scores. We evaluated participants’ meal companionship status by asking whether they had usually dined with companions for breakfast, lunch, or dinner during the past year. Statistical analysis was performed using chi-square tests and multivariate/multinomial logistic regression. We found depression to be less prevalent among participants who dined with companions at least once a day (adjusted OR: 0.26, 95% CI: 0.15–0.45, men; adjusted OR: 0.50, 95% CI: 0.34–0.74, women). In the moderate depression subgroup, participants who dined with companions at least once a day showed lower OR (adjusted OR: 0.28, 95% CI: 0.16–0.50, men; adjusted OR: 0.50, 95% CI: 0.32–0.76, women). Among participants who dined together, men’s severe depression dramatically decreased (adjusted OR: 0.05, 95% CI: 0.01–0.31). Thus, we found an association between dining with companions and the prevalence of depression among Korean adults. Dining with companions compared with dining alone signified a lower depression rate, especially among men. This study can provide an initiative to further analyze psychological and physiological effects of dining together and be applied to practical fields as education and societal campaigns.  相似文献   
73.
The coronavirus disease 2019 (COVID-19) resulted in a marked decrease in the number of patient visits for acute myocardial infarction and delayed patient response and intervention in several countries. This study evaluated the effect of the COVID-19 pandemic on the number of patients, patient response time (pain-to-door), and intervention time (door-to-balloon) for patients with ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation myocardial infarction (NSTEMI).Patients with STEMI or NSTEMI visiting a hospital in South Korea who underwent primary coronary intervention during the COVID-19 pandemic (January 29, 2020, to December 31, 2020) were compared with those in the equivalent period from 2018 to 2019. Patient response and intervention times were compared for the COVID-19 pandemic window (2020) and the equivalent period from 2018 to 2019.We observed no decrease in the number of patients with STEMI (P = .88) and NSTEMI (P = 1.00) during the COVID-19 pandemic compared to that in the previous years. Patient response times (STEMI: P = .39; NSTEMI: P = .59) during the overall COVID-19 pandemic period did not differ significantly. However, we identified a significant decrease in door-to-balloon time among patients with STEMI (14%; P < .01) during the early COVID-19 pandemic.We found that the number of patients with STEMI and NSTEMI was consistent during the COVID-19 pandemic and that no time delays in patient response and intervention occurred. However, the door-to-balloon time among patients with STEMI significantly reduced during the early COVID-19 pandemic, which could be attributed to decreased emergency care utilization during the early pandemic.  相似文献   
74.
Background  The technical difficulty of lymph node dissection in laparoscopy-assisted distal gastrectomy (LADG) remains a barrier for extending the indication for this modality and limits its widespread clinical practice. The aim of this study was to evaluate our institutional guidelines for LADG, limiting the indications for this modality to only clinical stage T1N0 or T1N1 gastric cancer. Methods  From January 2002 to October 2006, a total of 294 cases of LADG and 664 cases of open distal gastrectomy (ODG) for clinical T1N0 or T1N1 gastric cancer were performed at the National Cancer Center, Korea. The two groups’ clinicopathologic characteristics, surgical outcome, morbidity, and survival were compared. Results  The mean operating time for the LADG group was significantly longer than that for the ODG group (265.8 ± 56.3 vs. 171.4 ± 43.1 minutes, P < .001). The mean number of retrieved lymph nodes in the LADG group was higher than that of the ODG group (39.5 ± 14.7 vs. 37.2 ± 12.9, P = .017). The postoperative hospital stay was shorter in the LADG group (8.0 ± 3.3 vs. 10.5 ± 4.1 days, P < .001). The complications rate was lower for the LADG group than that for the ODG group (6.8% vs. 11.3%, P = .032). The overall survival rate was not significantly different between the two groups (P = .880). Conclusions  Before considering expanding the indications for LADG, developing a carefully thought-out guideline and conducting an audit are mandatory.  相似文献   
75.
Background Information on surgical complications of laparoscopy-assisted distal gastrectomy (LADG) and their risk factors is limited in the literature despite increasing popularity of this procedure. This study was performed to identify the surgical complications and their associated risk factors of LADG in early gastric cancer. Methods LADG was performed in 347 gastric cancer patients from January 2002 to December 2006 at the Korean National Cancer Center by four surgeons with ample experience of open gastric surgery before LADG. LADG indications for cases of gastric cancer at our institution are preoperatively diagnosed cT1N0 or cT1N1, except in cases with an absolute indication for endoscopic resection. Lymph node dissection of more than D1 + β was performed in all patients. Intraoperative and postoperative complications were reviewed and their risk factors were retrospectively analyzed by prospective database information. Results Forty complications occurred in 34 patients (9.8%), but there was no mortality. Intraoperative complications occurred in nine patients (2.6%), and open conversion was performed in eight (2.3%) of these patients. Early and late postoperative complications occurred in 21 (6.1%) and 10 (2.9%) patients, respectively. The most serious complication was vascular injury resulting in bleeding or organ ischemia, which occurred in seven patients. Degree of lymph node dissection and surgical inexperience were found to be risk factors of surgical complication (P = .023, odds ratio 2.832, 95% confidence interval 1.155–6.946 vs. P = .028, odds ratio 2.975, 95% confidence interval 1.127–7.854). Conclusions Lymph node dissection during LADG should be performed cautiously to prevent surgical complications like vascular injuries, especially during the surgeon’s early learning period.  相似文献   
76.
AIM: To investigate the anti-diabetogenic mechanism of Nardostachys jatamansi extract (NJE). METHODS: Mice were injected with streptozotocin viaa tail vein to induce diabetes. Rat insulinoma RINm5F cells and isolated rat islets were treated with interleukin1β and interferon-γ to induce cytotoxicity. RESULTS: Treatment of mice with streptozotocin resulted in hyperglycemia and hypoinsulinemia, which was conf irmed by immunohistochemical staining of the islets. The diabetogenic effects of streptozotocin were c...  相似文献   
77.
The epidemiology of hyperuricaemia and gout in Taiwan aborigines   总被引:4,自引:1,他引:4  
To determine the prevalence of hyperuricaemia, gout and gout-related factors in Central Taiwan Atayal aborigines, 342 subjects over 18 yr old were interviewed and examined. A questionnaire was designed to screen for signs and symptoms of gout and gout-related risk factors. Serum uric acid, triglyceride and creatinine were measured in all subjects. The prevalence of hyperuricaemia was 41.4% and that of gout 11.7% in aborigines. The uric acid level was 7.9+/-1.7 mg/dl in males and 5.7+/-1.5 in females, and differed significantly under age 70 yr (P < 0.001). Significantly increased triglyceride, creatinine and alcoholism was found in gouty patients compared with non-gouty patients. In 40 cases with gout, 54% had tophi and 35% of their first- degree relatives had gout. The high prevalence of hyperuricaemia and gout in Taiwan Atayal aborigines, a significant family predisposition, increased creatinine level and alcoholism suggest multiple factors affecting the hyperuricaemia.   相似文献   
78.
Two children are reported in whom intestinal pseudo-obstruction was the initial manifestation of systemic sclerosis. Gastrointestinal symptoms and skin changes resolved or improved in both children following treatment with prednisone and penicillamine (case 1) or methotrexate (case 2), although radiological changes of the gastrointestinal tract persisted at 3 and 2 yr of follow-up, respectively.   相似文献   
79.

Background/Aims

We evaluated the effectiveness of an endoscopic ultrasonography (EUS)-based treatment plan compared to an endoscopy-based treatment plan in selecting candidates with early gastric cancer (EGC) for endoscopic submucosal dissection based on the prediction of invasion depth.

Methods

We reviewed 393 EGCs with differentiated histology from 380 patients who underwent EUS from July 2007 to April 2010. The effectiveness of the EUS-based and endoscopy-based plans was evaluated using a simplified hypothetical treatment algorithm.

Results

The numbers of endoscopically determined mucosal, indeterminate, and submucosal cancers were 253 (64.4%), 56 (14.2%), and 84 (21.4%), respectively. Overall, the appropriate treatment selection rates were 75.3% (296/393) in the endoscopy-based plan and 71.5% (281/393) in the EUS-based plan (p=0.184). For endoscopic mucosal cancers, the appropriate treatment selection rates in the endoscopy-based plan were 88.1% (223/253), while the use of an EUS-based plan significantly decreased this rate to 81.4% (206/253) (p=0.036). For endoscopic submucosal cancers, the appropriate selection rates did not differ between the endoscopy-based plan (46.4%, 39/84) and the EUS-based plan (53.6%, 45/84) (p=0.070).

Conclusions

EUS did not increase the likelihood of selecting the appropriate treatment in differentiated-type EGC. Therefore, EUS may not be necessary before treating differentiated-type EGC, especially in endoscopically presumed mucosal cancers.  相似文献   
80.
A 66-year-old man with hepatocellular carcinoma (HCC) showed marked thrombocytosis (110.7 x 10(4)/microl). Bone marrow (BM) aspirates demonstrated an increase of mature megakaryocytes (MgK). The serum thrombopoietin (TPO) level was increased to about 100-fold that of the normal level in the terminal stage. However, the platelet count gradually decreased to 13.5 x 10(4)/microl. The autopsy specimen revealed normoplastic BM with decreased MgK, mainly consisting of the immature type, and it was negative for tumor cells. Liver specimen showed markedly fatty metamorphosis. Immunohistochemical staining of TPO demonstrated that hepatocytes were weakly stained and HCC cells strongly stained, suggesting TPO-producing HCC.  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