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   6893篇
  免费   675篇
  国内免费   13篇
耳鼻咽喉   53篇
儿科学   223篇
妇产科学   128篇
基础医学   798篇
口腔科学   240篇
临床医学   873篇
内科学   1516篇
皮肤病学   79篇
神经病学   571篇
特种医学   263篇
外科学   846篇
综合类   126篇
一般理论   16篇
预防医学   805篇
眼科学   51篇
药学   466篇
中国医学   2篇
肿瘤学   525篇
  2022年   50篇
  2021年   112篇
  2020年   69篇
  2019年   116篇
  2018年   131篇
  2017年   86篇
  2016年   93篇
  2015年   107篇
  2014年   171篇
  2013年   246篇
  2012年   279篇
  2011年   315篇
  2010年   210篇
  2009年   174篇
  2008年   306篇
  2007年   295篇
  2006年   226篇
  2005年   287篇
  2004年   283篇
  2003年   260篇
  2002年   254篇
  2001年   240篇
  2000年   222篇
  1999年   216篇
  1998年   108篇
  1997年   109篇
  1996年   103篇
  1995年   93篇
  1994年   81篇
  1993年   63篇
  1992年   186篇
  1991年   187篇
  1990年   175篇
  1989年   175篇
  1988年   167篇
  1987年   164篇
  1986年   134篇
  1985年   133篇
  1984年   95篇
  1983年   92篇
  1982年   67篇
  1981年   71篇
  1980年   57篇
  1979年   72篇
  1978年   71篇
  1977年   44篇
  1972年   39篇
  1971年   28篇
  1969年   29篇
  1967年   28篇
排序方式: 共有7581条查询结果,搜索用时 15 毫秒
1.
Background A high Mandard score implies a non-response to chemotherapy in oesophageal adenocarcinoma. However, some patients exhibit tumour volume reduction and a nodal response despite a high score. This study examines survival and recurrence patterns in these patients.Methods Clinicopathological factors were analysed using multivariable Cox regression assessing time to death and recurrence. Computed tomography-estimated tumour volume change was examined in a subgroup of consecutive patients.Results Five hundred and fifty-five patients were included. Median survival was 55 months (Mandard 1–3) and 21 months (Mandard 4 and 5). In the Mandard 4 and 5 group (332 patients), comparison between complete nodal responders and persistent nodal disease showed improved survival (90 vs 18 months), recurrence rates (locoregional 14.75 vs 28.74%, systemic 24.59 vs 48.42%) and circumferential resection margin positivity (22.95 vs 68.11%). Complete nodal response independently predicted improved survival (hazard ratio 0.34 (0.16–0.74). Post-chemotherapy tumour volume reduction was greater in patients with a complete nodal response (−16.3 vs −7.7 cm3, p = 0.033) with no significant difference between Mandard groups.Conclusion Patients with a complete nodal response to chemotherapy have significantly improved outcomes despite a poor Mandard score. High Mandard score does not correspond with a non-response to chemotherapy in all cases and patients with nodal downstaging may still benefit from adjuvant chemotherapy.Subject terms: Oesophageal cancer, Surgical oncology  相似文献   
2.
3.
ObjectivesSevere acute kidney injury (AKI) is a known risk factor for infection and mortality. However, whether stage 1 AKI is a risk factor for infection has not been evaluated in adults. We hypothesized that stage 1 AKI following cardiac surgery would independently associate with infection and mortality.MethodsIn this retrospective propensity score–matched study, we evaluated 1620 adult patients who underwent nonemergent cardiac surgery at the University of Colorado Hospital from 2011 to 2017. Patients who developed stage 1 AKI by Kidney Disease Improving Global Outcomes creatinine criteria within 72 hours of surgery were matched to patients who did not develop AKI. The primary outcome was an infection, defined as a new surgical-site infection, positive blood or urine culture, or development of pneumonia. Secondary outcomes included in-hospital mortality, stroke, and intensive care unit (ICU) and hospital length of stay (LOS).ResultsStage 1 AKI occurred in 293 patients (18.3%). Infection occurred in 20.9% of patients with stage 1 AKI compared with 8.1% in the no-AKI group (P < .001). In propensity-score matched analysis, stage 1 AKI independently associated with increased infection (odds ratio [OR]; 2.24, 95% confidence interval [CI], 1.37-3.17), ICU LOS (OR, 2.38; 95% CI, 1.71–3.31), and hospital LOS (OR, 1.30; 95% CI, 1.17-1.45).ConclusionsStage 1 AKI is independently associated with postoperative infection, ICU LOS, and hospital LOS. Treatment strategies focused on prevention, early recognition, and optimal medical management of AKI may decrease significant postoperative morbidity.  相似文献   
4.
BACKGROUND: Repairing dorsal nasal defects is a frequent challenge for dermatologic surgeons, mainly due to the high frequency of basal cell carcinomas on this site. Obvious scars, mismatched skin and distortion of the nasal contour are the surgical hazards that must be avoided in these cases. AIM: Our aim was to perform surgery involving a simple flap in order to repair medium to large defects on the dorsal side of the nose. METHODS: The dorsal horizontal advancement flap was studied in 12 patients, in order to evaluate the benefits and limits of this surgical procedure. RESULTS: The resulting scars on most of our patients were well-camouflaged among their natural skin lines, and there was neither distortion of the alar contour nor the nostril. CONCLUSIONS: This flap is easy to perform and, in selected cases, provides an outstanding alternative to second-intention healing, full-thickness skin grafts, transposition, rotation and pedicle flaps.  相似文献   
5.
6.
A study was conducted to evaluate the efficacy of family history factors as screening criteria for childhood hypercholesterolemia. When they were seen for routine care at one of eight office practices, 1005 prepubertal children underwent random serum cholesterol determinations. Parental and grandparental histories of cardiovascular risk factors and atherosclerotic complications prior to 55 years of age were also obtained. Of the initial group, 274 children had total cholesterol levels greater than or equal to 175 mg/dL, and 175 of these children returned for retesting after an overnight fast. A total of 88 children were found to have low-density lipoprotein-cholesterol (LDL-C) values greater than or equal to 90th percentile for age and sex. Maternal and paternal histories of hypercholesterolemia were significantly associated with elevated LDL-C (odds ratio = 7.3 and 2.9, respectively), but had extremely low sensitivities (0.09, 0.15) despite modest positive predictive values (0.42, 0.22). Grandparental histories of sudden death, peripheral vascular disease, and gout were associated with elevated LDL-C, but sensitivities and positive predictive values for all of these factors were less than 0.22. Family history factors most commonly recommended as criteria for cholesterol screening in children did not identify half of all the children with elevated LDL-C and did not selectively identify the most severely affected children. Adding information concerning the presence of childhood obesity did not result in appreciable improvement in LDL-C detection beyond that achieved by family history factors alone. It was concluded that if thorough identification of young children with elevated LDL-C is desired, inclusive population screening rather than a family history-based strategy would be the most effective approach.  相似文献   
7.
Quantitative immunoblotting assay of blood coagulation factor XII   总被引:2,自引:0,他引:2  
The immunoblotting technique was applied to the study of Factor XII (F.XII) in plasma. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) of whole plasma followed by electroblotting of the electropherograms to nitrocellulose (NC) membranes and immunologic detection by a double antibody technique was used. 125-F.XII was transferred to the NC membrane in amounts proportional to the amount applied to the gel provided that a constant amount of carrier protein was present. Based on this, a quantitative assay was developed using either normal plasma or F.XII dilutions in F.XII-deficient plasma as standards. The measurement of F.XII antigen by immunoblotting was reproducible and gave values similar to those obtained by radial immunodiffusion. Two normal plasma pools contained 26 and 29 μ/ml of F.XII according to the immunoblotting assay. Compared to other immunoassays, immunoblotting has the advantage of directly estimating the apparent molecular weight (MW) of the protein of interest. Thus, we could confirm the normal apparent MW (80,000) of a F.XII-like molecule previously isolated from a cross reacting material (CRM)-positive F.XII-deficient plasma. None of eight CRM-negative F.XII-deficient plasmas showed an 80,000 MW immunoreactive molecule. However, five of these eight plasmas had a faint autoradiographic band at 115,000 MW that was similarly seen in only three out of 43 individual normal plasmas. The nature of this 115,000 MW band remains to be defined.  相似文献   
8.
Visualization and pre-operative plan are critical to efficient and thorough case preparation. Congenitally missing teeth, coupled with improper tooth positioning, can compromise the aesthetic rehabilitation outcome. Utilizing pre-treatment digital photography as an outline for tooth reduction and laser tissue re-contouring may help to create a symmetric and pleasing smile, even under less ideal conditions.  相似文献   
9.
10.
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