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   9339篇
  免费   597篇
  国内免费   76篇
耳鼻咽喉   159篇
儿科学   241篇
妇产科学   282篇
基础医学   1062篇
口腔科学   141篇
临床医学   879篇
内科学   2328篇
皮肤病学   134篇
神经病学   990篇
特种医学   281篇
外科学   1617篇
综合类   85篇
一般理论   2篇
预防医学   618篇
眼科学   77篇
药学   520篇
  1篇
中国医学   28篇
肿瘤学   567篇
  2024年   12篇
  2023年   78篇
  2022年   209篇
  2021年   367篇
  2020年   194篇
  2019年   322篇
  2018年   334篇
  2017年   229篇
  2016年   283篇
  2015年   337篇
  2014年   414篇
  2013年   538篇
  2012年   803篇
  2011年   797篇
  2010年   405篇
  2009年   353篇
  2008年   624篇
  2007年   666篇
  2006年   582篇
  2005年   554篇
  2004年   499篇
  2003年   480篇
  2002年   374篇
  2001年   54篇
  2000年   42篇
  1999年   44篇
  1998年   56篇
  1997年   32篇
  1996年   35篇
  1995年   30篇
  1994年   21篇
  1993年   24篇
  1992年   15篇
  1991年   17篇
  1990年   15篇
  1989年   19篇
  1988年   9篇
  1987年   6篇
  1986年   5篇
  1985年   14篇
  1984年   10篇
  1983年   16篇
  1982年   14篇
  1981年   11篇
  1980年   8篇
  1979年   5篇
  1977年   5篇
  1976年   6篇
  1974年   5篇
  1971年   6篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.

Introduction

The aim of the present study was to evaluate the influence of blue thermal treatment on the torsional resistance behavior of M-Wire Reciproc files (VDW, Munich, Germany).

Methods

Ten M-Wire Reciproc R25 (25/0.08v) and 10 Reciproc Blue R25 (25/0.08v, VDW) instruments were used. The torque and angle of rotation at failure of new instruments (n = 10) were measured according to ISO 3630-1. Three millimeters of each instrument tip was clamped to a small load cell by a lever arm linked to the torsion axis. The fracture surface of all fragments was examined with a scanning electron microscope. Results were statistically analyzed using the Student t test at a significance level of P < .05.

Results

The maximum torsional strength of M-Wire Reciproc was higher than Reciproc Blue instruments (P < .05). Reciproc Blue instruments showed significantly higher angular rotation to fracture than M-Wire Reciproc instruments (P < .05). Scanning electron microscopy of the fracture surface showed similar and typical features of torsional failure for the 2 types of instruments, including concentric abrasion marks and the fibrous dimple marks at the center of rotation.

Conclusions

Reciproc Blue instruments showed a higher angle of rotation to fracture but a lower torque to failure than M-Wire Reciproc instruments.  相似文献   
992.

Objective

To evaluate the feasibility and safety of combined uterine artery embolization (UAE) using embosphere and surgical myomectomy as an alternative to radical hysterectomy in premenopausal women with multiple fibroids.

Materials and methods

Mid-term clinical outcome (mean, 25 months) of 12 premenopausal women (mean age, 38 years) with multiple and large symptomatic fibroids who desired to retain their uterus and who were treated using combined UAE and surgical myomectomy were retrospectively analyzed. In all women, UAE alone was contraindicated because of large (>10 cm) or subserosal or submucosal fibroids and myomectomy alone was contraindicated because of too many (>10) fibroids.

Results

UAE and surgical myomectomy were successfully performed in all women. Myomectomy was performed using laparoscopy (n = 6), open laparotomy (n = 3), hysteroscopy (n = 2), or laparoscopy and hysteroscopy (n = 1). Mean serum hemoglobin level drop was 0.97 g/dL and no blood transfusion was needed. No immediate complications were observed and all women reported resumption of normal menses. During a mean follow-up period of 25 months (range, 14–37 months), complete resolution of initial symptoms along with decrease in uterine volume (mean, 48%) was observed in all women. No further hysterectomy was required in any woman.

Conclusion

In premenopausal women with multiple fibroids, the two-step procedure is safe and effective alternative to radical hysterectomy, which allows preserving the uterus. Further prospective studies, however, should be done to determine the actual benefit of this combined approach on the incidence of subsequent pregnancies.  相似文献   
993.
Transplant glomerulitis (TG) can lead to the diagnosis of acute humoral rejection when associated with C4d. Recent data have shown that, in patients with donor-specific antibodies, TG is a sign of humoral rejection, even in the absence of C4d. However, the clinical significance of isolated TG, i.e. TG without C4d deposition or morphological evidence of rejection, has not been specifically studied in protocol biopsies of recipients without donor-specific antibodies. We compared 20 isolated TG-patients with 44 selected recipients without TG or any rejection-associated change. The two groups had similar baseline characteristics. After a 3 year follow-up, renal function, acute rejection rate, and development of HLA antibodies were not significantly different between the two groups. Isolated TG had no deleterious consequences on the 3 year graft outcome. Eleven patients of the glomerulitis-group had another allograft biopsy during follow-up: glomerular lesions returned to normal in six patients whereas the persistence of glomerulitis or features consistent with chronic transplant glomerulopathy were noticed in the remaining five patients. Four of these five patients had pretransplant non-donor specific HLA antibodies. In conclusion, although isolated TG had no impact on allograft function at 3 year, histological outcome could be related to patient sensitization.  相似文献   
994.

Introduction and hypothesis  

This is a prospective randomized controlled trial of cough versus no cough test in the tension-free vaginal tape (TVT) procedure to determine its effect upon voiding dysfunction and 12-month efficacy.  相似文献   
995.

Background

Clostridium difficile colitis (CDC) patients receiving chemotherapy for hematologic malignancies are anticipated to have worse outcomes than immunocompetent CDC patients.

Study design

An IRB approved retrospective cohort study (2004?C2009) identified an equal number (n?=?49) of CDC inpatients receiving chemotherapy for hematologic malignancies (CDC-HM) as well as CDC patients without malignancies (CDC-NM). Chi-squared tests, linear regression, and analysis of variance were used to compare outcomes.

Results

No difference (p?>?0.05) was noted between groups regarding age, hypertension, diabetes, COPD, or coronary artery disease. Approximately 62?% of CDC-HM patients required colony-stimulating factor for neutropenia. There was no difference (p?>?0.05) in peak lactate or creatinine levels. None of the CDC-HM group required colectomy, while four CDC-NM patients required surgery (p?=?0.04); neither group experienced death. No differences were noted regarding need for ICU admission for CDC or the need for vasopressors (p?>?0.05). Mean hospital length of stay was longer for the CDC-HM group (22?days vs. 10?days; p?=?0.001).

Conclusions

CDC-HM patients had longer lengths of stay than CDC-NM patients without an increase in rates of death, colectomy, or ICU admission. Outcomes in CDC-HM are better than many would anticipate, underscoring the current knowledge deficit regarding C. difficile infection.  相似文献   
996.
The main accepted principle to treat Kienb?ck disease is to decompress the lunate. Radius shortening is the most used technique. Three transverse osteotomies of the radius are described: neutral shortening osteotomy, lateral closing wedge osteotomy, and medial closing wedge osteotomy. Shortening the radius decompress the lunate and more or less the scaphoid. This deviates axial constraints toward ulna and triangular fibrocartilage complex. But the ulnar wrist is not able to support important axial constraints. The authors propose a solution to decompress only the lunate and not the scaphoid. This solution deviates axial constraints toward the scaphoid, which is naturally the most capable bone to support it. The authors describe a new radial nontransverse decompression wedge osteotomy. It allows to shorten the radius in front of the lunate. The fixation is done with a dorsal staple. To complete lunate decompression, authors propose to associate a metaphysal ulnar oblique shortening, essentially if ulnar variance is neutral or positive. The preliminar results on 10 cases are presented.  相似文献   
997.
998.
Study Type – Therapy (multi‐centre retrospective cohort) Level of Evidence 2b What's known on the subject? and What does the study add? Upper urinary tract urothelial carcinomas (UUT‐UCs) are rare tumours. Because of the aggressive pattern of UC, radical nephroureterectomy (RNU) with bladder cuff removal remains the ‘gold‐standard’ treatment. However, conservative strategies, such as segmental ureterectomy (SU) or endourological management, have also been developed in patients with imperative indications. Some teams are now advocating the use of conservative management more commonly in cases of elective indications of UUT‐UCs. Due to the paucity of cases of UUT‐UC, only limited data are available on the oncological outcomes afforded by conservative management. We retrospectively investigated the oncological outcomes after SU and RNU in a large multi‐institutional database. Overall, 52 patients were treated with SU and 416 with RNU. There was no statistical difference between the RNU and SU groups for the 5‐year probability of cancer‐specific survival, recurrence‐free survival and metastasis‐free survival. The type of surgery was not a significant prognostic factor in univariate analysis. The results were the same in a subgroup analysis of only unifocal tumours of the distal ureter with a diameter of <2 cm and of low stage (≤T2). Our results suggest that oncological outcomes after conservative treatment with SU are comparable to RNU for the management of UUT‐UC in select cases.

OBJECTIVE

  • ? To compare recurrence‐free survival (RFS), metastasis‐free survival (MFS) and cancer‐specific survival (CSS) after segmental ureterectomy (SU) vs radical nephroureterectomy (RNU) for urothelial carcinoma (UC) of the upper urinary tract (UUT‐UC) located in the ureter.

PATIENTS AND METHODS

  • ? We performed a multi‐institutional retrospective review of patients with UUT‐UC who had undergone RNU or SU between 1995 and 2010.
  • ? Type of surgery, Tumour‐Node‐Metastasis status, tumour grade, lymphovascular invasion and positive surgical margin were tested as prognostic factors for survival.

RESULTS

  • ? In all, 52 patients were treated with SU and 416 with RNU. The median (range) follow‐up was 26 (10–48) months.
  • ? The 5‐year probability of CSS, RFS and MFS for SU and RNU were 87.9% and 86.3%, respectively (P= 0.99); 37% and 47.9%, respectively (P= 0.48); 81.9% and 85.4%, respectively (P= 0.51).
  • ? In univariable analysis, type of surgery (SU vs RNU) failed to affect CSS, RFS and MFS (P= 0.94, 0.42 and 0.53, respectively).
  • ? In multivariable analyses, pT stage and pN stage achieved independent predictor status for CSS (P= 0.005 and 0.007, respectively); the positive surgical margin and pT stage were independent prognostic factors of RFS and MFS (P= 0.001, 0.04, 0.009 and 0.001, respectively).
  • ? The main limitation of the study is its retrospective design, which is due to the rarity of the disease.

CONCLUSIONS

  • ? Short‐term oncological outcomes after conservative treatment with SU are comparable to RNU for the management of UUT‐UC in select cases and should be considered an option.
  • ? In every other case, RNU still represents the ‘gold standard’ for the treatment of UUT‐UC.
  相似文献   
999.
Pulmonary sequestration is a relatively rare entity comprising a small portion of all congenital pulmonary malformations. Varying clinical techniques have been utilized to manage this disease process including abstaining from surgical intervention, endovascular procedures and operative approaches. We reviewed three case reports with varying presentations, each of which had a favorable outcome with definitive surgical treatment. In conclusion, we recommend that resection should continue to be the standard of care in both adolescent and adult patients with this disease process.KEY WORDS : Pulmonary sequestration, intralobar, case report  相似文献   
1000.
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