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   31828篇
  免费   2684篇
  国内免费   177篇
耳鼻咽喉   323篇
儿科学   1105篇
妇产科学   726篇
基础医学   3711篇
口腔科学   654篇
临床医学   3081篇
内科学   6783篇
皮肤病学   548篇
神经病学   2467篇
特种医学   1014篇
外科学   4775篇
综合类   807篇
一般理论   16篇
预防医学   2112篇
眼科学   1333篇
药学   2410篇
  1篇
中国医学   141篇
肿瘤学   2682篇
  2023年   202篇
  2022年   311篇
  2021年   785篇
  2020年   498篇
  2019年   725篇
  2018年   826篇
  2017年   586篇
  2016年   688篇
  2015年   787篇
  2014年   1060篇
  2013年   1262篇
  2012年   2063篇
  2011年   2124篇
  2010年   1216篇
  2009年   1064篇
  2008年   1848篇
  2007年   1805篇
  2006年   1662篇
  2005年   1591篇
  2004年   1577篇
  2003年   1394篇
  2002年   1255篇
  2001年   1143篇
  2000年   1031篇
  1999年   880篇
  1998年   316篇
  1997年   246篇
  1996年   215篇
  1995年   216篇
  1994年   194篇
  1993年   172篇
  1992年   519篇
  1991年   483篇
  1990年   441篇
  1989年   402篇
  1988年   364篇
  1987年   337篇
  1986年   333篇
  1985年   326篇
  1984年   223篇
  1983年   206篇
  1982年   147篇
  1981年   107篇
  1980年   112篇
  1979年   161篇
  1978年   93篇
  1977年   103篇
  1976年   70篇
  1974年   85篇
  1973年   71篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
961.
962.

Purpose

In 2007, the World Health Organization created a Surgical Safety Checklist (SSC) that encompassed a simple set of surgical safety standards. The threefold purpose of this study was to add ambulatory-specific items to the SSC, to introduce the items into an ambulatory surgical facility, and to determine if patient outcomes regarding postoperative pain and nausea/vomiting improved following implementation. In addition, safety attitudes, antibiotic timing, regional anesthesia/nerve blocks, preemptive pain medications, prophylactic antiemetics, length of stay, and hospital admission were also assessed.

Methods

After Research Ethics Board approval, staff complete a Safety Attitudes Questionnaire. Seven items were added to the SSC. Data were then collected on 180 surgical cases before SSC implementation and 195 cases following implementation. Compliance with each section of the SSC was assessed.

Results

On postoperative day one, the median (97.5% confidence interval [CI]) difference between pre- and post-implementation pain scores was 0.5 (97.5% CI, 0 to 1; P = 0.13), and the median difference in the rate of post-discharge nausea/vomiting was ?8.4% (97.5% CI, ?17.9 to 1.1; P = 0.06). There was no improvement in safety attitudes or any of the secondary outcomes, with the exception of the use of preemptive pain medications. Compliance with the three sections of the checklist, i.e., BRIEFING, TIME OUT, and DEBRIEFING was 99.49%, 97.95%, and 96.92%, respectively. There was low compliance in verbalization of the added “ambulatory-specific items”.

Conclusion

Potential reasons for lack of uptake and integration include poor “user” buy-in, an overly lengthy checklist, and lack of prioritization of ambulatory-specific items. A shortened SSC was developed based on the results of this study. This trial was registered at ClinicalTrials.gov ID: NCT00934310.  相似文献   
963.

Background

Complications associated with epidural analgesia in children have a reported incidence of 40-90 in 10,000 epidurals. We sought to determine the incidence of major complications with the use of continuous epidural analgesia that occurred in our centre over the past 15 years and to describe the nature of these complications.

Methods

The Acute Pain Service database at a tertiary care academic pediatric hospital was reviewed retrospectively over a 15-year period. Data were categorized according to patient age (neonate, infant, child one through eight years, and child > eight years), mode of insertion of the epidural (caudal, transsacral, lumbar, thoracic), complication type, and complication severity.

Results

Over the 15-year period, 3,152 epidurals were performed. The use of caudal-thoracic epidurals in neonates and infants has increased since 2007. Twenty-four major complications were identified (incidence, 7.6 in 1,000 epidurals). The rate of complications in neonates was 4.2% compared with 1.4% in infants, 0.5% in children aged one through eight years, and 0.8% in children over eight years of age. The two most common complications were local skin infection and drug error.

Conclusions

Our incidence of major complications and our finding that complications were more common in neonates and infants are both consistent with previously published data. The two most common types of complications are potentially preventable.  相似文献   
964.
The objective of this study was to evaluate the most common treatments performed for hip fractures over the last decade in the United States. The leading treatment for trochanteric fractures was internal fixation, accounting for 96%–98% of surgical treatments each year. For cervical fractures, hemiarthroplasty (HA), total hip arthroplasty (THA), and internal fixation were performed nearly 61%, 5%, and 33% of the time, respectively, each year without any sign of change during the period assessed. The surgical choice for cervical fractures varied greatly by patient age. In 2009, two-thirds of patients younger than 60 years underwent internal fixation while two-thirds of patients 60 years or older underwent HA. Regardless of patient age, HA was performed more often than THA for cervical hip fractures.  相似文献   
965.

Background

Previously active in the mid-1990s, the Canadian Airway Focus Group (CAFG) studied the unanticipated difficult airway and made recommendations on management in a 1998 publication. The CAFG has since reconvened to examine more recent scientific literature on airway management. The Focus Group’s mandate for this article was to arrive at updated practice recommendations for management of the unconscious/induced patient in whom difficult or failed tracheal intubation is encountered.

Methods

Nineteen clinicians with backgrounds in anesthesia, emergency medicine, and intensive care joined this iteration of the CAFG. Each member was assigned topics and conducted reviews of Medline, EMBASE, and Cochrane databases. Results were presented and discussed during multiple teleconferences and two face-to-face meetings. When appropriate, evidence- or consensus-based recommendations were made together with assigned levels of evidence modelled after previously published criteria.

Conclusions

The clinician must be aware of the potential for harm to the patient that can occur with multiple attempts at tracheal intubation. This likelihood can be minimized by moving early from an unsuccessful primary intubation technique to an alternative “Plan B” technique if oxygenation by face mask or ventilation using a supraglottic device is non-problematic. Irrespective of the technique(s) used, failure to achieve successful tracheal intubation in a maximum of three attempts defines failed tracheal intubation and signals the need to engage an exit strategy. Failure to oxygenate by face mask or supraglottic device ventilation occurring in conjunction with failed tracheal intubation defines a failed oxygenation, “cannot intubate, cannot oxygenate” situation. Cricothyrotomy must then be undertaken without delay, although if not already tried, an expedited and concurrent attempt can be made to place a supraglottic device.  相似文献   
966.

Background

Although previous studies have suggested that low preoperative 25-hydroxyvitamin D (25-OHD) is a risk factor for hypocalcemia after total thyroidectomy, the impact of preoperative 25-OHD on calcium (Ca)/parathyroid hormone (PTH) kinetics in the immediate postoperative period remains unclear. The study compared the postoperative Ca/PTH kinetics between different preoperative 25-OHD levels.

Patients

A total of 281 patients who underwent a total thyroidectomy were analyzed. Serum Ca was measured preoperatively within 1 h after surgery (Ca-D0) and on the following morning (Ca-D1). Preoperative 25-OHD was also measured after overnight fasting while postoperative PTH was checked at skin closure on day 0 (PTH-D0) and on the following morning on day 1 (PTH-D1). The Ca/PTH kinetics were compared between three groups (group I: preoperative 25-OHD < 10 ng/mL; group II: 25-OHD = 10–20 ng/mL; group III: 25-OHD > 20 ng/mL).

Results

Group I had significantly lower preoperative Ca (p = 0.016) and Ca-D0 (p = 0.036) but higher PTH-D1 (p = 0.015) than groups II and III. PTH-D0, Ca-D1, and the rate of clinically significant hypocalcemia were similar in the three groups. Group I had a significantly smaller Ca drop (?0.02 vs. 0.01 and 0.02 mmol/L, p = 0.011) and a tendency for a significantly smaller PTH drop (0.4 vs. 0.5 and 1.0 pmol/L, p = 0.073) than groups II and III. PTH-D1 (OR = 1.550) and 25-OHD (OR = 0.958) were independent factors for Ca drop from day 0 to day 1.

Conclusions

Although group I began with lower serum Ca, those patients tended to have a greater PTH response to Ca drop and so preoperative 25-OHD did not significantly affect the overall Ca kinetics from preoperative to day 1.  相似文献   
967.
968.

Background

The purpose of the present study was to determine whether intrahepatic injection of 131I-lipiodol (Lipiodol) is effective against recurrence of surgically resected hepatocellular carcinoma (HCC).

Methods

From June 2001 through March 2007, this nationwide multi-center prospective randomized controlled trial enrolled 103 patients 4–6 weeks after curative resection of HCC with complete recovery (52: Lipiodol, 51: Control). Follow-up was every 3 months for 1 year, then every 6 months. Primary and secondary endpoints were recurrence-free survival (RFS) and overall survival (OS), respectively, both of which were evaluated by the Kaplan–Meier technique and summarized by the hazard ratio (HR). The design was based on information obtained from a similar trial that had been conducted in Hong Kong.

Results

The Lipiodol group showed a small, and nonsignificant, improvement over control in RFS (HR = 0.75; 95 % confidence interval [95 % CI] 0.46–1.23; p = 0.25) and OS (HR = 0.88; 95 % CI 0.51–1.51; p = 0.64). Only two serious adverse events were reported, both with hypothyroidism caused by 131I-lipiodol and hepatic artery dissection during angiography.

Conclusions

The randomized trial provides insufficient evidence to recommend the routine use of 131I-lipiodol in these patients.  相似文献   
969.

Background

Oral calcium and calcitriol are often prescribed after total thyroidectomy to avoid biochemical and/or symptomatic hypocalcemia. We aimed to identify independent perioperative factors that correlated with the duration of calcium and/or calcitriol supplementation after total thyroidectomy.

Methods

Of 271 eligible patients, 48 (17.7 %) required calcium and/or calcitriol supplements on discharge. Patients were gradually weaned from the supplementation by one surgeon according to a biweekly algorithm based on serum calcium (Ca). Duration of supplementation was calculated from the date of operation to the date of ceasing all supplementation without biochemical hypocalcemia (i.e., serum adjusted Ca ≥8.44 mg/dL). The Cox regression analysis was performed to identify independent perioperative factors for duration of supplementation. The best cut-off value for these independent factors was determined by the receiver characteristic curve.

Results

In the multivariate analysis, parathyroid hormone (PTH) at skin closure (PTH-SC) (RR 1.742, 95 % CI 1.080–2.810) and on postoperative day 1 adjusted Ca (Ca-D1) (RR 77.526, 95 % CI 3.600–1669.57) were the only two independent determinants for shorter duration before ceasing all supplementation. The best cut-off values in predicting supplementation ≥6 months for PTH-SC and Ca-D1 were 7.08 pg/mL (sensitivity = 100 %, specificity = 60.5 %, PPV = 40.0 % and NPV = 100 %) and 7.88 mg/dL (sensitivity = 90.0 %, specificity = 55.3 %, PPV = 34.6 % and NPV = 95.5 %), respectively.

Conclusions

Both PTH-SC and Ca-D1 were independently associated with the duration of supplementation after total thyroidectomy. Almost all patients with PTH-SC ≥7.08 pg/mL or Ca-D1 ≥7.88 mg/dL did not require supplementation ≥6 months whereas about one third of patients with PTH-SC <7.08 pg/mL or Ca-D1 <7.88 mg/dL required supplementation ≥6 months.  相似文献   
970.
Introduction. Non-dialytic treatment (NDT) has become a recognized and important modality of treatment in end stage renal disease (ESRD) in certain groups of chronic kidney disease (CKD) patients. However, little is known about the prognosis of these NDT patients in terms of hospitalization rates and survival. We analyzed our experience in managing these NDT with a multidisciplinary team (MDT) approach over a three-year period. Patients and Methods. The Renal Unit at the Royal Liverpool University Hospital set up a dedicated MDT clinic to manage NDT patients in January 2003. Patients approaching end stage chronic kidney disease who chose not to dialyse were recruited from other nephrologists. The study group was classified according to age band (<70 years, 71–80 years, and >80 years), estimated glomerular filtration rate (eGFR) (<10 ml/min, 11–20 ml/min, and >20 ml/min) according to the Modified Diet In Renal Disease formula and Stoke comorbidity grade (SCG). The SCG is a validated scoring system for the survival of patients on renal replacement therapy. We also used the ERA-EDTA primary renal diagnosis codes. As there are no existing standards for NDT patients, we used the U.K. national set for haemodialysis patients as a reference and target for our NDT patients. Data was collected prospectively. Results. The median age was 79 years and the male: female ratio was approximately 1. The most common primary cause of kidney disease in the NDT study population was chronic renal failure of unknown cause n = 22 (31%), but the most common identifiable cause was diabetic nephropathy, n = 20 (28%). The most common comorbidity was ischaemic heart disease n = 25 (34%). Those achieving the standards for anaemia were 78% at referral. Only 30% of the NDT patients achieved the standard for blood pressure (<130/80 mmHg) at referral. Forty-three patients (60%) had no admissions at all. There were a total of 30 patients admitted on 58 occasions. Thirty-one (53%) of these were due to a non-renal cause. The median length of stay for the other NDT patients was 10 days. The median overall survival (life expectancy) was 1.95 years. The one-year overall survival was 65%. SCG was an independent prognostic factor in predicting survival in NDT patients studied (p = 0.005), the hazard ratio being 2.53, for each incremental increase in the SCG. At one year, the survival for comorbidity grade 0, 1 and 2 were 83%, 70% and 56% respectively. Of the 28 patients who died, 20 did so at home (71%). Discussion. The NDT of ESRD has become an important alternative modality in renal replacement therapy. With the emergence of epidemic proportions of CKD, more elderly patients with progressive renal disease will need to make informed decisions regarding renal replacement therapy. There is likely to be increasing number of elderly patients that will tolerate dialysis badly and who will be very dependent on others. We believe that there should be a multidisciplinary approach to assist the ESRD patients in choosing their modality of renal replacement therapy, and with an agreed care plan to support these patients in managing their chosen modality to achieve the best possible quality of life. There should be integrated services with primary care, community nurses, and palliative care teams to enable the majority of the patient's treatment to be carried out at home and to allow a dignified death. However. there was a statistically significant trend for shorter survival among those with greater comorbidities, as determined by the SCG. This is the first report of the potential importance of SCG as an independent prognostic factor in NDT patients. This will help us to counsel our patients in the future about their prognosis if they choose NDT as their modality of renal replacement therapy. Conclusion. Our prospective study is the first and currently the largest observational study of a multidisciplinary approach in the management of NDT patients. SCG was an independent prognostic factor in predicting survival. In those patients who chose not to dialyse, SCG provides a potentially useful indication of expected prognosis.  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