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   492篇
  免费   25篇
  国内免费   2篇
儿科学   25篇
妇产科学   22篇
基础医学   61篇
口腔科学   15篇
临床医学   39篇
内科学   165篇
皮肤病学   4篇
神经病学   10篇
特种医学   5篇
外科学   76篇
综合类   7篇
预防医学   49篇
眼科学   1篇
药学   14篇
中国医学   4篇
肿瘤学   22篇
  2023年   7篇
  2022年   12篇
  2021年   21篇
  2020年   11篇
  2019年   14篇
  2018年   24篇
  2017年   13篇
  2016年   16篇
  2015年   9篇
  2014年   17篇
  2013年   27篇
  2012年   21篇
  2011年   45篇
  2010年   22篇
  2009年   18篇
  2008年   34篇
  2007年   29篇
  2006年   22篇
  2005年   30篇
  2004年   31篇
  2003年   20篇
  2002年   18篇
  2001年   15篇
  2000年   10篇
  1999年   6篇
  1998年   2篇
  1997年   1篇
  1996年   1篇
  1995年   2篇
  1992年   1篇
  1991年   3篇
  1990年   3篇
  1989年   1篇
  1988年   2篇
  1987年   1篇
  1983年   2篇
  1982年   3篇
  1981年   1篇
  1978年   1篇
  1971年   1篇
  1969年   1篇
  1966年   1篇
排序方式: 共有519条查询结果,搜索用时 31 毫秒
1.
Background: Vitamin B12 deficiency after gastric surgery for obesity is due to a failure of separation of vitamin B12 from protein foodstuffs and to a failure of absorption of crystalline vitamin B12 in the presence of intrinsic factor. The purpose of this study was to determine which of four oral doses of crystalline vitamin B12 was most effective in treating vitamin B12 deficiency in 102 patients. Methods and Results: At time of entry into the study, the patients had a serum vitamin B12 < 100 pmol L −1, were 29.9 ± 21.7 months post-op, were 37 ± 8 years old and had a body mass index of 30 ± 6 kg m−2. Eight (8%) had had a vertical banded gastroplasty and 94 (92%) a gastric bypass. For the first 3 months all patients received 350 μg per day of crystalline vitamin B12 and all increased their serum vitamin B12 levels to over 100 pmol L−1. The patients were then assigned to receive for a further 3 month period one of four oral doses of crystalline vitamin B12-100 μg, 250 μg, 350 μg and 600 μg. Serum vitamin B12 levels were greater than 150 pmol L−1 after 6 months in 83.3% of patients who received 100 μg; 92.3% of patients who received 250 μg; 94.7% after 350 μg and 95.2% after 600 μg (p%0.525). Conclusion: At least 350 μg per day is the appropriate oral dose of crystalline vitamin B12 after gastric surgery for obesity to correct low serum vitamin B12 levels in 95% of patients.  相似文献   
2.
HYPOTHESIS: To assess the applicability and efficacy of endoluminal colonic wall stents (ECWSs) in the management of large bowel obstruction (LBO). DESIGN: Inception cohort study. SETTING: University-based tertiary medical center. PATIENTS: Eleven consecutive patients with LBO in the absence of peritonitis. INTERVENTION: Placement of ECWS under endoscopic and fluoroscopic guidance. MAIN OUTCOME MEASURES: The success rate in ECWS placement, the efficacy in decompressing the obstruction, and the patency rate of the ECWS. RESULTS: Successful placement of ECWSs was obtainable in 10 of 11 patients. Once placed, all 10 patients achieved immediate decompression of their LBO. Eight patients had malignant obstructions associated with distant spread of disease; 3 patients had diverticular disease. Among those with malignant obstruction, 6 patients had successful and lasting palliation without colostomy, 1 patient underwent 1-stage resection 1 month later with no evidence of obstruction, and 1 patient could not be stented so diversion was done. None of the patients with diverticular disease required diversion: 2 had complete bowel preparation followed by resection with primary anastomosis, whereas the third declined surgery. Four of the 10 patients required overlapping ECWSs to bridge the stricture. One patient required a second ECWS secondary to recurrence of obstruction after stent migration and has continued palliation of his stage 4 rectal cancer for the last 11 months. No other complications were encountered. CONCLUSIONS: Urgent surgery with colostomy for LBO was avoided in 10 of 11 patients because of successful placement of ECWSs. We believe that endoscopic colonic stenting is safe, effective, and lasting, and should be considered as initial nonoperative management in all patients seen with LBO in the absence of peritonitis.  相似文献   
3.
Effect of narghile and cigarette smoking on newborn birthweight   总被引:1,自引:1,他引:0  
Objective  To assess the effect of narghile smoking on the weight of newborns.
Design  Historical retrospective cohort.
Setting  Six major hospitals in Greater Beirut, Lebanon.
Population  Consecutive singleton newborns delivered from August 2000 to August 2003.
Methods  Obstetric and nursery charts were reviewed to obtain information about maternal and neonatal variables. Information concerning initiation of smoking, dose of smoking, smoking habits during pregnancy, and socio-demographic characteristics was collected through interviews with mothers.
Main outcome measures  Low birthweight and newborn birthweight.
Results  Exclusive narghile smokers constituted 4.4% (378/8592) of women. Multiparas were significantly more likely to smoke cigarettes and narghile. Mothers smoking narghile more than once per day were at 2.4 increased odds of having low birthweight infants compared with nonsmoking mothers (OR 2.4; 95% CI 1.2–5.0) after adjusting for confounding variables. No difference was noted between women smoking narghile in the first trimester and those initiating smoking in subsequent trimesters regarding low birthweight.
Conclusions  Narghile smoking more than once per day increases the odds of low birthweight by a 2.4-fold compared with nonsmokers, although to a lesser extent than cigarette smoking.  相似文献   
4.
Background:Transcatheter aortic valve replacement (TAVR) is a worldwide adopted procedure with rapidly evolving practices. Regional and temporal variations are expected to be found.Objective:To compare TAVR practice in Latin America with that around the world and to assess its changes in Latin America from 2015 to 2020.Methods:A survey was applied to global TAVR centers between March and September 2015, and again to Latin-American centers between July 2019 and January 2020. The survey consisted of questions addressing: i) center’s general information; ii) pre-TAVR evaluation; iii) procedural techniques; iv) post-TAVR management; v) follow-up. Answers from the 2015 survey of Latin-American centers (LATAM15) were compared with those of other centers around the world (WORLD15) and with the 2020 updated Latin-American survey (LATAM20). A 5% level of significance was adopted for statistical analysis.Results:250 centers participated in the 2015 survey (LATAM15=29; WORLD15=221) and 46 in the LATAM20. Combined centers experience accounted for 73 707 procedures, with WORLD15 centers performing, on average, 6- and 3-times more procedures than LATAM15 and LATAM20 centers, respectively. LATAM centers performed less minimalistic TAVR than WORLD15 centers, but there was a significant increase in less invasive procedures after 5 years in Latin-American centers. For postprocedural care, a lower period of telemetry and maintenance of temporary pacing wire, along with less utilization of dual antiplatelet therapy was observed in LATAM20 centers.Conclusion:Despite still having a much lower number of procedures, many aspects of TAVR practice in Latin-American centers have evolved in recent years, followingthe trend observed in developed country centers.  相似文献   
5.
6.

Purpose

A prospective observational study is conducted to identify independent predictors of pain and morphine consumption following abdominal hysterectomy.

Methods

Preoperative State Trait Anxiety Inventory (STAI), Numerical Rating Scales (NRS) for anxiety and pain expectations, thermal pain thresholds and pain scores at forearm and incision site, and pain scores generated from the insertion of an intravenous catheter were measured in female patients undergoing abdominal hysterectomy. Pearson correlations between the predictors and the two outcome measures postoperative pain scores and morphine consumption were studied and multiple regression analysis was conducted to identify independent predictors (primary outcome). Secondary outcomes included cut-off values of predictive tools for morphine consumption.

Results

Data from 60 patients were analyzed. STAI state anxiety, NRS pain expectations, and NRS anxiety scores were identified as independent predictors of postoperative morphine consumption. We identified a cut-off value of 4.5 (sensitivity 90 %, specificity of 60 %) for the NRS anxiety and a cut-off of 42.5 (sensitivity 70 %, specificity 70 %) for the state anxiety STAI score for increased postoperative morphine consumption.

Conclusions

Preoperative STAI state anxiety scores and NRS pain expectations are independent predictors for increased morphine consumption following hysterectomy. The STAI state anxiety tool and NRS 0-10 anxiety tool can be used interchangeably. The NRS 0-10 anxiety is a much simpler tool than STAI state anxiety and is associated with a higher sensitivity for high morphine consumption. Thermal pain thresholds and IV pain scores were not predictive of postoperative morphine consumption.
  相似文献   
7.
Pulmonary artery aneurysm (PAA) is a rare entity with fatal complications. Its silent course contributes to large aneurysms with compression symptoms. We present a 39-year-old female idiopathic pulmonary arterial hypertension patient with a giant PAA causing severe pulmonary regurgitation (PR) and symptomatic left main coronary artery compression (LMCA). Since she had a failed LMCA stenting attempt, she underwent surgery. A valve-sparing David-like pulmonary trunk reconstruction and coronary artery bypass were performed. This case illustrates that David-like reconstruction procedure can be applied to the PAA with severe PR.  相似文献   
8.
The proteasome is a large protease complex consisting of multiple catalytic subunits that function simultaneously to digest protein substrates. This complexity has made deciphering the role each subunit plays in the generation of specific protein fragments difficult. Positional scanning libraries of peptide vinyl sulfones were generated in which the amino acid located directly at the site of hydrolysis (P1 residue) was held constant and sequences distal to that residue (P2, P3, and P4 positions) were varied across all natural amino acids (except cysteine and methionine). Binding information for each of the individual catalytic subunits was obtained for each library under a variety of different conditions. The resulting specificity profiles indicated that substrate positions distal to P1 are critical for directing substrates to active subunits in the complex. Furthermore, specificity profiles of IFN-gamma-regulated subunits closely matched those of their noninducible counterparts, suggesting that subunit swapping may modulate substrate processing by a mechanism that does require a change in the primary sequence specificity of individual catalytic subunits in the complex. Finally, specificity profiles were used to design specific inhibitors of a single active site in the complex. These reagents can be used to further establish the role of each subunit in substrate processing by the proteasome.  相似文献   
9.
This article is a continuation of our previously published annual reviews of transcatheter aortic valve replacement (TAVR). In 2017, TAVR further established a foothold in the management of intermediate risk patients with the publication of SURTAVI trial. Randomized trials also addressed the use of cerebral protection during TAVR and single versus dual antiplatelet therapy after TAVR. Newer generation valve systems continued to be studied for their efficacy and safety. This paper summarizes the major studies published in 2017.
  相似文献   
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