全文获取类型
收费全文 | 8996篇 |
免费 | 731篇 |
国内免费 | 67篇 |
专业分类
耳鼻咽喉 | 63篇 |
儿科学 | 336篇 |
妇产科学 | 304篇 |
基础医学 | 1177篇 |
口腔科学 | 283篇 |
临床医学 | 859篇 |
内科学 | 1867篇 |
皮肤病学 | 78篇 |
神经病学 | 541篇 |
特种医学 | 353篇 |
外科学 | 1483篇 |
综合类 | 176篇 |
一般理论 | 10篇 |
预防医学 | 426篇 |
眼科学 | 342篇 |
药学 | 486篇 |
中国医学 | 31篇 |
肿瘤学 | 979篇 |
出版年
2024年 | 9篇 |
2023年 | 59篇 |
2022年 | 74篇 |
2021年 | 216篇 |
2020年 | 146篇 |
2019年 | 193篇 |
2018年 | 255篇 |
2017年 | 136篇 |
2016年 | 190篇 |
2015年 | 247篇 |
2014年 | 336篇 |
2013年 | 357篇 |
2012年 | 550篇 |
2011年 | 626篇 |
2010年 | 398篇 |
2009年 | 374篇 |
2008年 | 549篇 |
2007年 | 594篇 |
2006年 | 568篇 |
2005年 | 516篇 |
2004年 | 460篇 |
2003年 | 415篇 |
2002年 | 314篇 |
2001年 | 307篇 |
2000年 | 259篇 |
1999年 | 211篇 |
1998年 | 91篇 |
1997年 | 85篇 |
1996年 | 75篇 |
1995年 | 55篇 |
1994年 | 58篇 |
1993年 | 47篇 |
1992年 | 112篇 |
1991年 | 99篇 |
1990年 | 102篇 |
1989年 | 101篇 |
1988年 | 78篇 |
1987年 | 75篇 |
1986年 | 67篇 |
1985年 | 58篇 |
1984年 | 45篇 |
1983年 | 38篇 |
1982年 | 31篇 |
1981年 | 35篇 |
1980年 | 27篇 |
1979年 | 27篇 |
1978年 | 18篇 |
1977年 | 29篇 |
1976年 | 21篇 |
1975年 | 14篇 |
排序方式: 共有9794条查询结果,搜索用时 12 毫秒
91.
Risk of deep vein thrombosis following laparoscopic rectosigmoid cancer resection in chinese patients 总被引:1,自引:0,他引:1
Cheung HY Chung CC Yau KK Siu WT Wong SK Chiu E Li MK 《Asian journal of surgery / Asian Surgical Association》2008,31(2):63-68
OBJECTIVE: The aim of this study was to evaluate the incidence of postoperative deep vein thrombosis (DVT) in Chinese patients who underwent laparoscopic resection of rectal or sigmoid cancer in the absence of thromboprophylaxis. METHODS: Patients with adenocarcinoma of the sigmoid colon or rectum scheduled for laparoscopic resection were recruited. Neither chemoprophylaxis nor mechanical methods against DVT were employed. They were scheduled to have routine duplex ultrasound of both lower limbs perioperatively. RESULTS: In a 12-month period, 50 patients were recruited. Postoperative DVT occurred in 19 (38%) patients. None needed anticoagulation. Complete resolution of the thrombus was noted in 10 (53%) patients 12 weeks after operation, and in six patients 36 weeks after operation. Female sex was identified as being associated with a higher incidence of DVT. Age, smoking, preoperative neoadjuvant chemoirradiation, preoperative metastasis, duration of operation, conversion and postoperative complications did not appear to be risk factors for DVT. CONCLUSION: The incidence of asymptomatic calf vein DVT is relatively high after laparoscopic resection for rectosigmoid cancers in the Chinese population. However, complete resolution occurred without the use of anticoagulant therapy in the majority of cases. It is thus difficult to advocate the routine use of anticoagulant prophylaxis. 相似文献
92.
Human leukocyte antigen (HLA) associations have been frequently reported in childhood steroid-responsive nephrotic syndrome
(SRNS) in other populations. The aim of this study was to characterize the immunogenetic background of Singaporean Chinese
patients with childhood SRNS. We determined the HLA class I (HLA-A* and HLA-B*) as well as class II (HLA-DRB1*, HLA-DQB1*) gene polymorphisms using the polymerase chain reaction-sequence specific oligonucleotide (PCR-SSO) technique, in patients
with SRNS (n=64) and normal controls (n=236 for HLA-A*, n=80 for HLA-B*, HLA-DRB1* and HLA-DQB1*). The frequency of HLA-A*11 allele was significantly higher in the SRNS patients compared to controls (78.1% vs 54.2%, respectively; relative risk, RR=3.01,
Pc=0.011). However, there was no significant difference in the allele frequencies of HLA-B*, HLA-DRB1* and HLA-DQB1* between the SRNS patients and controls, unlike that in previous studies. Our data suggest that the immunogenetic background
of Singaporean Chinese with childhood SRNS was different from that in other populations. As HLA-A*11 has been strongly associated with other autoimmune diseases, it is conceivable that the HLA-A*11-specific motif may play a role in the development of the abnormal T-cell-mediated immune response that may be responsible
for triggering the proteinuria seen in SRNS.
Received: 24 April 2001 / Revised: 14 November 2001 / Accepted: 18 November 2001 相似文献
93.
Altered swelling behavior of femoral cartilage following joint immobilization in a canine model. 总被引:3,自引:0,他引:3
Daria A Narmoneva Herman S Cheung Jean Y Wang David S Howell Lori A Setton 《Journal of orthopaedic research》2002,20(1):83-91
Periods of reduced joint loading have been shown to induce changes in the biochemical composition. metabolism and mechanics of articular cartilage. In this study, changes in cartilage swelling behavior were studied following a 4-week period of joint immobilization, using a recently developed osmotic loading technique [J. Biomech, 32 (1999) 401-408]. The magnitude and distribution of swelling strains were measured in cartilage-bone samples equilibrated in physiological and hypotonic saline, relative to a hypertonic reference NaCl solution. Physicochemical parameters (glycosaminoglycan fixed charge density and water volume fraction) were determined in site-matched cartilage samples. The experimental data for swelling strains, fixed charge density and water volume fraction were used with a triphasic mechano-chemical theory [J. Biomech. Eng. 113 (1991) 245-258] to determine the effect of joint immobilization on the tensile modulus of the cartilage solid matrix. Four weeks of immobilization resulted in a significant increase in the magnitude of swelling-induced strains, and a significant decrease in fixed charge density in cartilage, as compared with the contralateral controls. Joint immobilization also resulted in decreases in values for the modulus of cartilage, as compared with the contralateral controls. Our results suggest that 4 weeks of joint immobilization had a significant effect on cartilage mechanical function that may be linked to collagen changes in the cartilage extracellular matrix. 相似文献
94.
Wing‐Hong Li Moon‐Tong Cheung Candace N.S. Ho Ting‐Pong Fung Kai‐Ming Ko Kelvin K.W. Yau 《Surgical Practice》2007,11(4):138-143
Aim: To examine the survival benefit of liver and lung resection for colorectal metastasis and the potential prognostic factors that affect patient survival. Methods: All patients who had resection of lung or liver metastasis for colorectal metastasis in Queen Elizabeth Hospital, Hong Kong from 1995 to 2004 were retrospectively reviewed. The overall and disease‐free survival was analysed, in particularly between liver and lung metastasis. All factors that may have affected the survival were entered into Cox's proportional hazards regression model to identify significant variables associated with survival. Results: At 5 years, the overall survival of patients who had resection of lung and liver metastasis was 44% and 38%, respectively; the disease‐free survival was 26% and 24%, respectively. Overall and disease‐free survival of patients with resection of lung metastasis was comparable to those with resection of liver metastasis. The differentiations of primary tumour and time to metastasis were shown to be significant prognostic factors influencing overall survival. Those patients with systemic chemotherapy after resection of colorectal metastasis demonstrated a significantly higher probability of overall survival. Conclusion: Resection of lung and liver metastases from colorectal origin was safe and both procedures improved survival. The use of chemotherapy after resection of metastasis significantly improved the overall survival. 相似文献
95.
96.
Qiong Xu Junqi Ling Gary S P Cheung Yan Hu 《Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics》2007,104(4):e109-e113
OBJECTIVE: The aim of this study was to evaluate the sealing ability of 4 different obturation techniques by using a glucose leakage test. STUDY DESIGN: Eighty extracted single-rooted maxillary incisors were selected for the study. The teeth were decoronated and the root canals prepared using ProFile rotary instruments to an apical dimension of size 40 (0.06 taper). The specimens were then randomly divided into 4 experimental groups (n = 15) and filled with gutta-percha and sealer by using either cold lateral compaction, warm vertical compaction, Thermafil, or the E & Q Plus system. Another 10 teeth each served as the positive and negative controls. A glucose leakage model was used for quantitative evaluation of the coronal-to-apical microleakage at 24 hours, 1, 2, 3, 5, 8, and 12 weeks. RESULTS: No significant difference in the cumulative amount of leakage was found among the 4 groups at 24 hours and 1 week (Kruskal-Wallis test, P > .05). Lateral compaction showed significantly more leakage than the other 3 techniques at longer intervals (Mann-Whitney U test, P < .008). No significant difference was found between vertical compaction, Thermafil, and E & Q Plus at all observation times. CONCLUSIONS: Warm vertical compaction, Thermafil, and the E & Q Plus system showed a better sealing result than cold lateral compaction of gutta-percha at extended observation periods. The glucose leakage method used in this study was able to provide a nondestructive, quantitative, and long-term evaluation of the sealing ability of root canal fillings. 相似文献
97.
BACKGROUND: There is a paucity of data regarding whether sterile handling of endotracheal tubes (ETTs) impacts the incidence and prevalence of pneumonia in the emergency, urgent, or elective clinical scenarios. Intensive care units employ infection control and reduction schemes to reduce pneumonia rates. METHODS: A MEDLINE search of the English-language literature for the last 30 years was performed using the keywords "endotracheal intubation," "intubation," "pneumonia," "sinusitis," "tracheobronchitis," "nosocomial infection," and "infection." Data were limited to those papers addressing the role of sterile handling or passage of ETTs, infection with antibiotic-resistant micro-organisms, antibiotic prophylaxis, and the role of virulence determinants in supporting invasive infection. Also, a convenience sample of a single author's patients requiring tracheal intubation was undertaken. Data were acquired on tube handling, success of insertion, and subsequent occurrence of pneumonia. RESULTS: Virtually no data exist on the impact of sterile ETT handling, but unsterile manipulation of the ETT prior to insertion is common (112 of 154 intubation events). Within the limited patient sample, no conclusions may be drawn regarding the impact of unsterile handling on pneumonia rates, although sinusitis after nasotracheal intubation clearly increases the incidence of pneumonia. Biofilm generation as a facilitator of bacterial colonization of artificial airway surfaces is a ubiquitous virulence determinant that is not ameliorated by antibiotic administration. CONCLUSIONS: Unsterile ETT handling and insertion techniques are not clearly associated with pneumonia induction, but physiologically sound approaches that retard biofilm production may decrease pneumonia rates. 相似文献
98.
Outcome assessment of bracing in adolescent idiopathic scoliosis by the use of the SRS-22 questionnaire 总被引:1,自引:0,他引:1 下载免费PDF全文
The SRS-22 questionnaire is specifically designed for the assessment of quality of life in spinal deformity patients. This study is the first to use it to assess the quality of life of adolescent idiopathic scoliosis patients under brace treatment and compares the results with an observational group matched by age and curve magnitude. Forty-six patients were enrolled into each group. Overall, it was found that patients under observation had a significantly better quality of life than braced patients. Specifically, the domains for function/activity and self-image were most affected. This effect was most apparent in those with a curve magnitude of under 20 degrees . The scores did not improve significantly with the duration of brace wear, suggesting little adaptation. This study has implications for treatment, and more attention will need to be given to those with mild but progressive curves to help improve patients' understanding of their treatment and hence their compliance and satisfaction. 相似文献
99.
A. M. Sawka A. Gafni P. Boulos K. Beattie A. Papaioannou A. Cranney D. A. Hanley J. D. Adachi A. Cheung E. A. Papadimitropoulos L. Thabane 《Osteoporosis international》2007,18(6):819-827
Summary Hip fractures are an important problem in nursing homes. Hip protectors are external devices that decrease the risk of hip
fracture in elderly nursing home residents. We estimated the overall healthcare cost savings from a hypothetical strategy
of provision of hip protectors to elderly nursing home residents in Ontario, Canada. In a recent meta-analysis, we determined
that a strategy of provision of hip protectors decreases the risk of hip fracture in nursing home residents.
Introduction Our objective was to determine whether the provision of hip protectors to all Ontario nursing home residents aged ≥65 years
could result in cost savings, stemming from reductions in initial hospitalizations for hip fracture.
Methods We conducted a cost analysis from a Ministry of Health perspective (one year cycle length). The efficacy of the intervention
was estimated from a meta-analysis of randomized controlled trials.
Results A strategy of provision of hip protectors to all 60,775 elderly Ontario nursing home residents could result in an overall
mean cost savings of 6.0 million Canadian dollars in one year (95% credibility interval, −26.4 million, 39.7 million), with
a probability of cost savings of 0.63 (assuming no additional labor costs). In sensitivity analyses, decreasing hip protector
price increased cost savings, whereas additional labor expenditures for application for hip protectors decreased cost savings.
Conclusion In conclusion, if hip protectors can be provided to elderly Ontario nursing home residents without additional labor expenditures,
there is a reasonable probability that such a strategy may result in healthcare cost savings. 相似文献
100.
BACKGROUND: Laparoscopic appendectomy has been widely practiced for uncomplicated appendicitis; various reports demonstrated its merits in assisting diagnosis, reducing postoperative pain, analgesic requirement, and incidence of wound infection. The role of laparoscopy in management of complicated appendicitis, ie, gangrenous, perforated appendicitis and appendiceal abscess, remains undefined. Currently, the choice of operative approach is mostly at the surgeons' discretion. A retrospective study was conducted in our institution to review the feasibility, safety, and efficacy of laparoscopic appendectomy for patients with complicated appendicitis. STUDY DESIGN: From January 1999 to January 2004, records of patients older than 14 years of age with diagnosis of appendicitis were retrieved from computer database for analysis. All patients underwent diagnostic laparoscopy to confirm diagnosis of complicated appendicitis, and patients subsequently underwent either laparoscopic or open appendectomies. Patients' demographics data and perioperative outcomes from the two groups were compared. RESULTS: During the study period, 1,133 patients with acute appendicitis underwent operations in our institution. Two hundred forty-four patients (21.5%) with complicated appendicitis were identified by laparoscopy, of which 175 underwent laparoscopic appendectomy (LA) and 69 had open appendectomy (OA). Both groups of patients were comparable in demographics. Mean operative time was 55 minutes for LA group and 70 minutes for the OA group (p<0.001). Mean hospital stay was 5 days and 6 days for LA and OA group respectively (p<0.001). There was one conversion patient (0.6%) in the LA group who suffered from wound infection, and there were seven (10%) wound infections in the OA group (p=0.001). There were 10 cases (5.7%) of intraabdominal collection in the LA group and 3 (4.3%) in the OA group (p=0.473). There was no mortality in the current series. CONCLUSIONS: Laparoscopic appendectomy for complicated appendicitis is feasible and safe. It is associated with a significantly shorter operative time, lower incidence of wound infection, and reduced length of hospital stay when compared with patients who had open appendectomy. 相似文献