全文获取类型
收费全文 | 12558篇 |
免费 | 320篇 |
国内免费 | 33篇 |
专业分类
耳鼻咽喉 | 74篇 |
儿科学 | 411篇 |
妇产科学 | 372篇 |
基础医学 | 1752篇 |
口腔科学 | 457篇 |
临床医学 | 639篇 |
内科学 | 2426篇 |
皮肤病学 | 236篇 |
神经病学 | 690篇 |
特种医学 | 371篇 |
外科学 | 1869篇 |
综合类 | 963篇 |
预防医学 | 1263篇 |
眼科学 | 284篇 |
药学 | 742篇 |
1篇 | |
中国医学 | 120篇 |
肿瘤学 | 241篇 |
出版年
2024年 | 5篇 |
2023年 | 88篇 |
2022年 | 168篇 |
2021年 | 285篇 |
2020年 | 177篇 |
2019年 | 1824篇 |
2018年 | 1479篇 |
2017年 | 661篇 |
2016年 | 199篇 |
2015年 | 139篇 |
2014年 | 356篇 |
2013年 | 348篇 |
2012年 | 431篇 |
2011年 | 429篇 |
2010年 | 347篇 |
2009年 | 322篇 |
2008年 | 309篇 |
2007年 | 344篇 |
2006年 | 223篇 |
2005年 | 132篇 |
2004年 | 95篇 |
2003年 | 96篇 |
2002年 | 42篇 |
2001年 | 58篇 |
2000年 | 60篇 |
1999年 | 46篇 |
1998年 | 34篇 |
1997年 | 27篇 |
1996年 | 21篇 |
1995年 | 29篇 |
1994年 | 23篇 |
1993年 | 9篇 |
1992年 | 17篇 |
1991年 | 13篇 |
1990年 | 9篇 |
1987年 | 5篇 |
1986年 | 5篇 |
1985年 | 318篇 |
1984年 | 534篇 |
1983年 | 411篇 |
1982年 | 444篇 |
1981年 | 399篇 |
1980年 | 360篇 |
1979年 | 329篇 |
1978年 | 270篇 |
1977年 | 193篇 |
1976年 | 248篇 |
1975年 | 209篇 |
1974年 | 183篇 |
1973年 | 149篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
《Journal of pediatric surgery》2023,58(9):1613-1617
BackgroundThe goal of this study was to characterize contemporary performance benchmarks and risk factors associated with negative appendectomy (NA) in children with suspected appendicitis.MethodsA multicenter retrospective cohort analysis of children undergoing appendectomy for suspected appendicitis was performed using data from the 2016–2021 NSQIP-Pediatric Appendectomy Targeted Public Use Files. Multivariable regression was used to evaluate the influence of year, age, sex, and WBC count on NA rate, and to generate rate estimates for NA based on different combinations of demographic characteristics and WBC profiles.Results100,322 patients were included from 140 hospitals. The overall NA rate was 2.4%, and rates decreased significantly during the study period (2016: 3.1% vs. 2021: 2.3%, p < 0.001). In adjusted analyses, the highest risk for NA was associated with a normal WBC (<9000/mm3; OR 5.31 [95% CI: 4.87–5.80]), followed by female sex (OR 1.55 [95% CI: 1.42–1.68]) and age <5 years (OR 1.64 [95% CI 1.39, 1.94]). Model-estimated risk for NA varied significantly across demographic and WBC strata, with a 14.4-fold range in rates between subgroups with the lowest and highest predicted risk (males 13–17 years with elevated WBC [1.1%] vs. females 3–4 years with normal WBC [15.8%]).ConclusionsContemporary NA rates have decreased over time, however NA risk remains high in children without a leukocytosis, particularly for girls and children <5 years of age. These data provide contemporary performance benchmarks for NA in children with suspected appendicitis and identify high-risk populations where further efforts to mitigate NA risk should be targeted.Level of EvidenceIII. 相似文献
2.
《Vaccine》2022,40(7):1001-1009
Vaccination guidelines for dogs and cats indicate that core vaccines (for dogs, rabies, distemper, adenovirus, parvovirus; for cats, feline parvovirus, herpes virus-1, calicivirus) are essential to maintain health, and that non-core vaccines be administered according to a clinician’s assessment of a pet’s risk of exposure and susceptibility to infection. A reliance on individual risk assessment introduces the potential for between-practice inconsistencies in non-core vaccine recommendations. A study was initiated to determine non-core vaccination rates of dogs (Leptospira, Borrelia burgdorferi, Bordetella bronchiseptica, canine influenza virus) and cats (feline leukemia virus) in patients current for core vaccines in veterinary practices across the United States. Transactional data for 5,531,866 dogs (1,670 practices) and 1,914,373 cats (1,661 practices) were retrieved from practice management systems for the period November 1, 2016 through January 1, 2020, deidentified and normalized. Non-core vaccination status was evaluated in 2,798,875 dogs and 788,772 cats that were core-vaccine current. Nationally, median clinic vaccination rates for dogs were highest for leptospirosis (70.5%) and B. bronchiseptica (68.7%), and much lower for canine influenza (4.8%). In Lyme-endemic states, the median clinic borreliosis vaccination rate was 51.8%. Feline leukemia median clinic vaccination rates were low for adult cats (34.6%) and for kittens and 1-year old cats (36.8%). Individual clinic vaccination rates ranged from 0 to 100% for leptospirosis, B. bronchiseptica and feline leukemia, 0–96% for canine influenza, and 0–94% for borreliosis. Wide variation in non-core vaccination rates between clinics in similar geographies indicates that factors other than disease risk are driving the use of non-core vaccines in pet dogs and cats, highlighting a need for veterinary practices to address gaps in patient protection. Failure to implement effective non-core vaccination strategies leaves susceptible dogs and cats unprotected against vaccine-preventable diseases. 相似文献
3.
4.
5.
Ngai-Yin Chan Chi-Chung Choy Ho-Chuen Yuen Hoi-Fan Chow Ho-Fai Fong 《The Canadian journal of cardiology》2019,35(4):396-404
Background
Persistent iatrogenic atrial septal defect (iASD) is a common but poorly characterized complication after cryoballoon (CB) pulmonary vein isolation (PVI) procedures. We therefore investigate its prevalence, evolution, risk factors, and clinical outcomes in a prospective longitudinal study.Methods
A total of 108 patients (41 women, mean age 57 ± 11.3) underwent CB PVI for AF. Serial transesophageal echocardiography (TEE) was performed 9 months and then annually until 6 years after the procedure to study the characteristics of persistent iASD.Results
Persistent iASD occurred in 33 (30.6%) patients 9 months after CB PVI. Spontaneous closure of iASD was found in 6 (22.2%) and 3 (15.8%) patients 2 and 3 years after the procedures, respectively. No spontaneous closure was observed on 4, 5, and 6-year TEE follow-up. The projected long-term persistence rate of iASD after CB PVI was therefore 20% (30.6% × 0.778 × 0.842). Using multivariate logistic regression, a higher number of cryoapplications (≥ 2 minutes) was the only independent predictor of persistent iASD 9 months after CB PVI (odds ratio [OR] 1.207; 95% confidence interval [CI], 1.033-1.411, P = 0.018). Two (1.9%) patients with significantly larger iASD size than the others (long diameter 12.6 ± 0.8 vs 3.7 ± 1.5 mm, P < 0.001; short diameter 10.9 ± 0.2 vs 3 ± 1.1 mm, P < 0.001) required percutaneous closure because of exertional dyspnea and right ventricular enlargement. Over 129.7 patient-years follow-up, during which iASD persisted, there was no occurrence of neurologic events.Conclusions
Approximately one fifth of patients undergoing CB PVI will have permanently persistent iASD. Patients with defect sizes of greater than 10 mm may need percutaneous closure due to significant left-to-right shunting. 相似文献6.
Haonan Guo Rui Zhang Justice Afrifa Yuanyuan Wang Jingcui Yu 《Pathology, research and practice》2019,215(6):152403
PurposeWe previously demonstrated that the functional inactivation of DAL-1 and TOB1 promotes an aggressive phenotype in gastric cancer cells, but the links between both genes and the survival of patients with gastric cancer are unknown. Here, we investigated the correlations of the expression levels of DAL-1 and TOB1 with the progression of gastric cancer.MethodsA total of 270 patients who underwent resectable gastrectomy were included. The expression of DAL-1 and TOB1 was detected by immunohistochemistry.ResultsLow expression of DAL-1 in cancer tissue was significantly associated with tumor site (p < 0.05), histological grade (p < 0.01), depth of invasion (p < 0.05), lymph node metastasis status (p < 0.05), Lauren classification (p < 0.001), and clinical stage (p < 0.01). A lower level of TOB1 was observed in gastric cancer patients with diffuse type disease compared to patients with either intestinal or mixed type disease (p < 0.001). Additionally, Spearman’s correlation analysis revealed that decreased expression of DAL-1 was positively correlated with low TOB1 expression (r=0.304, p < 0.001). The survival analysis showed that low levels of DAL-1 and TOB1 were significantly associated with poor survival of gastric cancer patients (p <0.001 and p < 0.05, respectively).ConclusionThe downregulation of DAL-1 and TOB1 expression is associated with shorter survival of gastric cancer patients. Hence, DAL-1 and TOB1 may be considered potential novel markers for predicting the outcomes of patients with gastric cancer. 相似文献
7.
Pavan Brahmamdam Stephen L. Carveth Mary Smyth Brian S. Gendelman M. Jeffrey Maisels 《Journal of pediatric surgery》2019,54(9):1800-1803
PurposeTo examine what proportion of caregivers, if given a choice, would choose medical versus surgical treatment of appendicitis and what factors would be important in their decision.MethodsA survey was devised and given to the caregivers of children presenting to the pediatrician for a routine visit in community and academic pediatric clinics. The survey presented a summary of outcomes after medical (non-operative) and surgical treatment of uncomplicated appendicitis. Participants were then asked to choose medical versus surgical treatment if their child were to develop appendicitis. They were also asked to rate the importance of certain factors in their decision ? 1 being “not important” and 5 being “very important”.ResultsFour hundred surveys were distributed with an 86.2% (345/400) response rate. Six percent (21/342) of respondents reported a history of appendicitis and 49.4% (168/340) reported having known someone who had appendicitis. The majority of respondents, 85.3% (284/333), were mothers. A minority of respondents, 41.7% (95% CI: 36.7, 47.0), chose medical treatment over surgery for appendicitis. There was no statistical difference in the proportion of mothers (41.6%) versus fathers who chose medical treatment (41.3%). Caregivers who chose medical treatment were more likely to rate time in hospital (p = .008) and time out of school (p = 05) as important in decision making when compared with those who chose surgery. Those who chose surgical treatment were more likely to rate risk of recurrent appendicitis (p < .001) as important to decision making. In the multivariate analysis, those who rated time in hospital as very important had more than twice the odds of choosing medical therapy (OR 2.20, p = 0.02) when compared with those who rated it as less important. Not knowing someone who has had appendicitis was significantly associated with choosing medical therapy when compared with those who do know someone who has had appendicitis, OR 2.3, p = .002. Rating pain as very important was also significantly associated with choosing medical therapy, when compared to those rating pain 1–3, OR 3.38, p = .03.ConclusionsIn this survey of caregivers of children presenting for routine care, 41.7% would choose medical, or non-operative, therapy for their children with acute appendicitis. The risk of recurrence, time in hospital, and time out of school, pain, and knowing someone who has had appendicitis were all important factors that families may consider when making a decision. These data may be useful for surgeons counseling patients on which treatment to pursue. 相似文献
8.
9.
10.