全文获取类型
收费全文 | 2092765篇 |
免费 | 158681篇 |
国内免费 | 5775篇 |
专业分类
耳鼻咽喉 | 28525篇 |
儿科学 | 68107篇 |
妇产科学 | 59503篇 |
基础医学 | 296695篇 |
口腔科学 | 56994篇 |
临床医学 | 184862篇 |
内科学 | 414997篇 |
皮肤病学 | 47102篇 |
神经病学 | 170534篇 |
特种医学 | 80901篇 |
外国民族医学 | 782篇 |
外科学 | 317677篇 |
综合类 | 50719篇 |
现状与发展 | 9篇 |
一般理论 | 702篇 |
预防医学 | 161270篇 |
眼科学 | 47808篇 |
药学 | 148817篇 |
16篇 | |
中国医学 | 5428篇 |
肿瘤学 | 115773篇 |
出版年
2019年 | 16665篇 |
2018年 | 23282篇 |
2017年 | 18073篇 |
2016年 | 19931篇 |
2015年 | 22631篇 |
2014年 | 32116篇 |
2013年 | 47852篇 |
2012年 | 64827篇 |
2011年 | 68911篇 |
2010年 | 41014篇 |
2009年 | 38987篇 |
2008年 | 64058篇 |
2007年 | 67816篇 |
2006年 | 68413篇 |
2005年 | 66723篇 |
2004年 | 63659篇 |
2003年 | 60961篇 |
2002年 | 59180篇 |
2001年 | 100658篇 |
2000年 | 103134篇 |
1999年 | 86445篇 |
1998年 | 24356篇 |
1997年 | 22172篇 |
1996年 | 22155篇 |
1995年 | 20784篇 |
1994年 | 19117篇 |
1993年 | 17965篇 |
1992年 | 65744篇 |
1991年 | 62801篇 |
1990年 | 60804篇 |
1989年 | 58125篇 |
1988年 | 53633篇 |
1987年 | 52507篇 |
1986年 | 49569篇 |
1985年 | 47278篇 |
1984年 | 35802篇 |
1983年 | 30395篇 |
1982年 | 18390篇 |
1981年 | 16210篇 |
1979年 | 32171篇 |
1978年 | 22619篇 |
1977年 | 18902篇 |
1976年 | 17900篇 |
1975年 | 18975篇 |
1974年 | 22822篇 |
1973年 | 21967篇 |
1972年 | 20631篇 |
1971年 | 18888篇 |
1970年 | 18080篇 |
1969年 | 16861篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
Bob C. Mulder Merel A. A. van Lelyveld Sigrid C. J. M. Vervoort Anne Marike Lokhorst Cees M. J. van Woerkum Jan M. Prins 《Health communication》2016,31(1):35-46
Since the introduction of cART (combination antiretroviral therapy), HIV has evolved into a chronic disease such that it requires lifelong medical treatment to which patients must adhere. Communication with health care providers is pivotal in supporting patients to adapt to having HIV and adhering to treatment, in order to maintain health and quality of life. Previous research indicates that communication is optimal when it matches patient preferences for information exchange, relationship establishment, and involvement in treatment decisions. The aim of the present study is to explore HIV patient communication preferences as well as patient experiences with their providers (not) matching their preferences. A second aim is to explore provider beliefs about patient preferences and provider views on optimal communication. Data were collected through interviews with 28 patients and 11 providers from two academic hospitals. Results indicate that patient preferences reflect their cognitive, emotional, and practical needs such that patients look to increase their sense of control over their HIV. Patients aim to further increase their sense of control (by proxy) through their relationship with their providers and through their decisional involvement preferences. Providers are well aware of patient communication preferences but do not explicate underlying control needs. Implications for clinical practice are discussed. 相似文献
103.
104.
Letter: faecal volatile organic metabolites,promising biomarkers in inflammatory bowel disease and Letter: faecal volatile organic metabolites as novel diagnostic biomarkers in inflammatory bowel disease. Authors’ reply 下载免费PDF全文
I. Ahmed R. Greenwood B. Costello N. Ratcliffe C. Probert 《Alimentary pharmacology & therapeutics》2016,43(11):1241-1242
105.
106.
Maggie L. Westfal David C. Chang Cassandra M. Kelleher 《Journal of pediatric surgery》2019,54(1):140-144
Purpose
The purpose of this study was to evaluate trends in demographics and outcomes of pediatric breast cancer in a United States population-based cohort.Methods
The Surveillance, Epidemiology, and End Results (SEER) database was utilized to identify all pediatric patients with malignant breast tumors between 1973 and 2014. Analysis was performed using Stata Statistical Software version 13.1. Associations between categorical variables were made using X2 test. Log-rank test was used for univariate survival analysis. Kaplan–Meier analysis investigated five-year survival rates across several variables. Adjusted analysis was performed using a Cox Proportional-Hazards regression.Results
134 patients with breast malignancies were identified. Carcinoma was the most prevalent histology (48.5%), followed by fibroepithelial tumors (FETs) (35.1%), and sarcoma (14.2%). FETs were twice as common in black compared to nonblack patients (56.3% vs. 29.0%, p?<?0.01). Analyzing histology by stage revealed that 100% of FETs were early stage disease (p?<?0.0001). 46.7% of the tumors tested were ER/PR negative, more than twice as many compared to the published adult estimate of 20.0%. Unadjusted survival analysis revealed worse survival for patients with adenocarcinoma/sarcomas, advanced stage, and high grade disease, without a survival difference between races.Conclusion
Breast cancer remains a rare malignancy among pediatric patients. Although black patients were found to have more noncarcinomatous tumors with less advanced disease, this did not confer a survival advantage.Type of study
Retrospective cohort study.Level of evidence
Level III. 相似文献107.
Julie A. Schmidt Georgina K. Fensom Sabina Rinaldi Augustin Scalbert Paul N. Appleby David Achaintre Audrey Gicquiau Marc J. Gunter Pietro Ferrari Rudolf Kaaks Tilman Kühn Heiner Boeing Antonia Trichopoulou Anna Karakatsani Eleni Peppa Domenico Palli Sabina Sieri Rosario Tumino Bas Bueno-de-Mesquita Antonio Agudo Maria-Jose Sánchez María-Dolores Chirlaque Eva Ardanaz Nerea Larrañaga Aurora Perez-Cornago Nada Assi Elio Riboli Konstantinos K. Tsilidis Timothy J. Key Ruth C. Travis 《International journal of cancer. Journal international du cancer》2020,146(3):720-730
Metabolomics may reveal novel insights into the etiology of prostate cancer, for which few risk factors are established. We investigated the association between patterns in baseline plasma metabolite profile and subsequent prostate cancer risk, using data from 3,057 matched case–control sets from the European Prospective Investigation into Cancer and Nutrition (EPIC). We measured 119 metabolite concentrations in plasma samples, collected on average 9.4 years before diagnosis, by mass spectrometry (AbsoluteIDQ p180 Kit, Biocrates Life Sciences AG). Metabolite patterns were identified using treelet transform, a statistical method for identification of groups of correlated metabolites. Associations of metabolite patterns with prostate cancer risk (OR1SD) were estimated by conditional logistic regression. Supplementary analyses were conducted for metabolite patterns derived using principal component analysis and for individual metabolites. Men with metabolite profiles characterized by higher concentrations of either phosphatidylcholines or hydroxysphingomyelins (OR1SD = 0.77, 95% confidence interval 0.66–0.89), acylcarnitines C18:1 and C18:2, glutamate, ornithine and taurine (OR1SD = 0.72, 0.57–0.90), or lysophosphatidylcholines (OR1SD = 0.81, 0.69–0.95) had lower risk of advanced stage prostate cancer at diagnosis, with no evidence of heterogeneity by follow-up time. Similar associations were observed for the two former patterns with aggressive disease risk (the more aggressive subset of advanced stage), while the latter pattern was inversely related to risk of prostate cancer death (OR1SD = 0.77, 0.61–0.96). No associations were observed for prostate cancer overall or less aggressive tumor subtypes. In conclusion, metabolite patterns may be related to lower risk of more aggressive prostate tumors and prostate cancer death, and might be relevant to etiology of advanced stage prostate cancer. 相似文献
108.
Luis J García-Flórez Guillermo Gómez-álvarez Ana M Frunza Luis Barneo-Serra Manuel F Fresno-Forcelledo 《World journal of gastrointestinal surgery》2015,7(9):196-202
AIM: To establish the association between lymph node involvement and the response to neoadjuvant therapy in locally advanced rectal cancer.METHODS: Data of 130 patients with mid and low locally advanced rectal adenocarcinoma treated with neoadjuvant chemoradiation followed by radical surgery over a 5-year period were reviewed. Tumor staging was done by endorectal ultrasound and/or magnetic resonance imaging. Tumor response to neoadjuvant therapy was determined by T-downstaging and tumor regression grading (TRG). Pathologic complete response (pCR) is defined as the absence of tumor cells in the surgical specimen (ypT0N0). The varying degrees TRG were classified according to Mandard’s scoring system. The evaluation of the response is based on the comparison between previous clinico-radiological staging and the results of pathological evaluation. χ2 and Spearman’s correlation tests were used for the comparison of variables.RESULTS: Pathologic complete response (pCR, ypT0N0, TRG1) was observed in 19 cases (14.6%), and other 18 (13.8%) had only very few residual malignant cells in the rectal wall (TRG2). T-downstaging was found in 63 (48.5%). Mean lymph node retrieval was 9.4 (range 0-38). In 37 cases (28.5%) more than 12 nodes were identified in the surgical specimen. Preoperative lymph node involvement was seen in 77 patients (59.2%), 71 N1 and 6 N2. Postoperative lymph node involvement was observed in 41 patients (31.5%), 29 N1 and 12 N2, while the remaining 89 were N0 (68.5%). In relation to ypT stage, we found nodal involvement of 9.4% in ypT0-1, 22.2% in ypT2 and 43.7% in ypT3-4. Of the 37 patients considered “responders” to neoadjuvant therapy (TRG1 and 2), there were only 4 N+ (10.8%) and the remainder N0 (89.2%). In the “non responders” group (TRG 3, 4 and 5), 37 cases were N+ (39.8%) and 56 (60.2%) were N0 (P < 0.001).CONCLUSION: Response to neoadjuvant chemoradiation in rectal cancer is associated with lymph node involvement. 相似文献
109.
110.
Wen Wang Yanmei Liu Chuan Yu Jing Tan Weiyi Xiong Duo Dong 《Expert opinion on drug safety》2020,19(3):339-347
ABSTRACTObjectives: Limited evidence has suggested that cefoperazone-sulbactam causes coagulation disorders and bleeding.Methods: The authors conducted a retrospective study to compare patients receiving cefoperazone-sulbactam versus those treated with cefoperazone-tazobactam or ceftazidime. Propensity-score matching was used to explore whether treatment with cefoperazone-sulbactam increased the risk of prothrombin time (PT) prolongation, coagulation disorders, and bleeding, or decreased platelets (PLT).Results: The cohort included 23,242 patients. Among patients receiving cefoperazone-sulbactam, the risk of PT prolongation, coagulation disorders, decreased PLT, and bleeding was 5.3%, 9.2%, 15.7%, and 4.2%, respectively. Propensity-score matching analyses suggested that cefoperazone-sulbactam increased the risk of PT prolongation (aOR 2.26, 95% CI 1.61–3.18), coagulation disorders (aOR 1.81, 95% CI 1.43–2.30), and decreased PLT (aOR 1.46, 95% CI 1.25–1.72), but not increase bleeding (aOR 1.05, 95% CI 0.79–1.40) compared with ceftazidime. Patients receiving cefoperazone-sulbactam had higher risk of PT prolongation (aOR 1.53, 95% CI 1.11–2.10), coagulation disorders (aOR 1.53, 95% CI 1.21–1.95), but not decreased PLT (aOR 0.93, 95% CI 0.81–1.07) or bleeding (aOR 1.11, 95% CI 0.87–1.42), compared with those receiving cefoperazone-tazobactam.Conclusion: Cefoperazone-sulbactam may be associated with a higher risk of PT prolongation and coagulation disorders compared with cefoperazone-tazobactam and ceftazidime. 相似文献