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   9142篇
  免费   564篇
  国内免费   46篇
耳鼻咽喉   55篇
儿科学   211篇
妇产科学   111篇
基础医学   1298篇
口腔科学   30篇
临床医学   872篇
内科学   2349篇
皮肤病学   118篇
神经病学   760篇
特种医学   359篇
外科学   1658篇
综合类   23篇
一般理论   2篇
预防医学   375篇
眼科学   75篇
药学   588篇
中国医学   22篇
肿瘤学   846篇
  2023年   52篇
  2022年   92篇
  2021年   230篇
  2020年   122篇
  2019年   242篇
  2018年   244篇
  2017年   196篇
  2016年   199篇
  2015年   268篇
  2014年   332篇
  2013年   422篇
  2012年   708篇
  2011年   730篇
  2010年   413篇
  2009年   392篇
  2008年   591篇
  2007年   626篇
  2006年   589篇
  2005年   661篇
  2004年   566篇
  2003年   539篇
  2002年   556篇
  2001年   77篇
  2000年   54篇
  1999年   92篇
  1998年   119篇
  1997年   73篇
  1996年   69篇
  1995年   46篇
  1994年   60篇
  1993年   52篇
  1992年   27篇
  1991年   28篇
  1990年   33篇
  1989年   23篇
  1988年   26篇
  1987年   23篇
  1986年   13篇
  1985年   16篇
  1984年   14篇
  1983年   13篇
  1982年   14篇
  1981年   18篇
  1980年   11篇
  1979年   13篇
  1976年   10篇
  1975年   6篇
  1973年   7篇
  1972年   7篇
  1971年   6篇
排序方式: 共有9752条查询结果,搜索用时 13 毫秒
71.

Purpose

BRAF V600 mutations are frequent in melanomas, and BRAFV600-targeted therapy have dramatic, but often transitory, efficacy in stage IV patients. Prognosis of patients with American Joint Committee on Cancer (AJCC) stage III melanoma is heterogeneous. We aimed to determine the overall survival (OS) of stage III patients with a nodal deposit of ??2?mm according to BRAF V600 mutations and other previously reported prognostic criteria.

Methods

This retrospective study included 105 consecutive patients with stage III cutaneous melanomas. Most patients underwent a prospective follow-up. BRAF V600 mutations were detected by sequencing and pyrosequencing of DNA in samples containing >60?% melanoma cells.

Results

BRAF mutations (p.V600E and p.V600K in 83 and 14?% of cases, respectively) were detected in 40?% of the patients. For patients with and without BRAF mutations, death occurred in 83.3 and 60.3?%, with a median OS of 1.4 and 2.8?years, respectively. Patient age, primary melanoma ulceration, number of invaded lymph nodes, AJCC staging at study entry, and BRAF status were linked to OS in the univariate analysis. The only characteristics associated with OS in the multivariate analysis were number of invaded lymph nodes (P?=?0.005, hazard ratio 2.2, 95?% confidence interval 1.3?C3.9) and BRAF status (P?=?0.005, hazard ratio 1.9, 95?% confidence interval 1.2?C3.1).

Conclusions

BRAF V600 status could be used to stage melanoma patients with nodal deposits. Our results may also help to plan adjuvant trials in these patients, for whom the low tumor load may induce longer efficacy of BRAF-targeted therapies.  相似文献   
72.
The 2007 World Health Organization histologic grading of meningiomas is associated with recurrence and clinical outcome. However, distinction of grade I from grade II (atypical) meningiomas can be challenging. In the World Health Organization classification, there are 4 parameters on the basis of which grade II status can be determined: mitotic rate, cytoarchitectural features, brain invasion, and/or histologic subtype. Furthermore, this classification fails to detect grade I recurrent meningiomas, for which other prognostic criteria would be needed. The aim of this study was to evaluate the respective value of several markers involved in cell cycle as effective tools to predict recurrence. This retrospective study was based on a series of 59 meningiomas (grade I: 32 of 59, grade II: 27 of 59, all harboring ≥4 mitoses/1.6 mm), analyzed with the following immunohistochemical markers: MCM6, Ki-67, PHH3, cyclin D1, and p53. We found a significant correlation between histologic grade and mean labeling index for MCM6 (grade I: 21.8% vs. grade II: 65.8%; P<0.001), Ki-67 (3.2% vs. 16.9%; P<0.001), PHH3 (0.7‰ vs. 2.8‰; P<0.001), cyclin D1 (50.4% vs. 70.0%; P=0.005), and p53 (17.3% vs. 32.4%; P=0.017). Histologic grading and mitotic index were correlated with progression-free survival (P=0.010 and P=0.020, respectively). A nearly linear correlation was found between progression-free survival and staining for MCM6 (P<0.001), Ki-67 (P=0.003), and PHH3 (P=0.037) but not for cyclin D1 (P=0.400) and p53 (P=0.758). The interobserver agreement coefficients for MCM6, Ki-67, PHH3, cyclin D1, and p53 were, respectively, 0.97 (95% confidence interval, 0.95-0.98), 0.93 (0.89-0.96), 0.81 (0.70-0.88), 0.90 (0.83-0.94), and 0.84 (0.73-0.90). In conclusion, because of its strong level of expression and sharp difference in labeling index between indolent and recurrent tumors, MCM6 is the most efficient marker to identify tumors with a high risk of recurrence.  相似文献   
73.
IntroductionSecondary hyperparathyroidism sometimes is lacking despite authentic vitamin D insufficiency (VDI) and the concept of functional hypoparathyroidism with a protective role on bone status has been proposed. Therefore, we tested the hypothesis that its prevalence was very low in a population of women with a peripheral fragility fracture.MethodsWe conducted our study in postmenopausal women, admitted for such a fracture in our Fracture Liaison Service. All had bone mineral density (BMD), biochemical assessment and a medical visit.ResultsTwo hundred and thirty seven women (72.9 ± 11.6-year-old) were included and 90.4% had VDI (25[OH]D  30 ng/mL). Yet, 87.9% of the latter had normal PTH levels less or equal to 64 ng/L. In this population with VDI (n = 214), we found no PTH plateau level related to 25(OH)D. Since a recent study reported an increase in the risk of fracture only when 25(OH)D was below 15 ng/mL, we then used this value as a new threshold. We observed a significant difference in hip BMD between patients with 25(OH)D either less or equal to or greater than 15 ng/mL. However, 81.2% of the formers were still with normal PTH with no difference in BMD whether PTH level was above or within normal range.ConclusionIn a population of postmenopausal women with a fragility fracture, we found that 25(OH)D less or equal to 15 ng/mL was associated with significantly lower hip BMD. Even using this low threshold, we found a high prevalence of functional hypoparathyroidism and it was not associated with any difference in hip or spine BMD. Overall, our results do not support the hypothesis of a protective effect of this biological profile.  相似文献   
74.
OBJECTIVE: The objective of our study was to analyze the sonography examinations of nine consecutive patients with a history of distal radius fracture treated by open reduction and internal fixation of the volar plate who were referred by hand surgeons for sonography of the dorsal aspect of the wrist. CONCLUSION: We postulate that impingement of the extensor tendons in patients with distal radius fracture treated by volar plating starts with local hyperemia and is followed by tenosynovitis and, finally, by partial and complete tendon tears. Sonography is an effective, dynamic, and noninvasive technique with which to diagnose and evaluate damage to the extensor tendons and their synovial sheaths.  相似文献   
75.
76.
77.
78.
Laparoscopic sleeve gastrectomy (LSG) is a new restrictive bariatric procedure increasingly indicated in the treatment of morbid obesity. Postoperative complications are mainly represented by gastric fistula with an occurrence rate of 0% to 5.1% in the literature. This complication is difficult to manage and requires multiple radiological, endoscopic, and surgical procedures. We report herein the case of a 23-year-old woman who underwent LSG for morbid obesity. This patient was reoperated for peritonitis due to a gastric fistula located on the top of the staple line. Five months later, she complained of a cough with fever and expectoration. A methylene blue test and a computed tomography scan diagnosed a postoperative bronchogastric fistula. After failure of aggressive conservative management, radical surgery was performed with total gastrectomy, reconstruction of the diaphragm using the extended latissimus dorsi flap, and a pulmonary lobectomy. This case report highlights the possible issue of the complex management of gastric fistula after LSG.  相似文献   
79.
Long‐term outcomes in renal transplant recipients withdrawn from steroid and submitted to further minimization of immunosuppressive regimen after 1 year are lacking. In this multicenter study, 204 low immunological risk kidney transplant recipients were randomized 14.2 ± 3.7 months post‐transplantation to receive either cyclosporine A (CsA) + azathioprine (AZA; n = 53), CsA + mycophenolate mofetil (MMF; n = 53), or CsA monotherapy (n = 98). At 3 years postrandomization, the occurrence of biopsy for graft dysfunction was similar in bitherapy and monotherapy groups (21/106 vs. 26/98; P = 0.25). At 10 years postrandomization, patients’ survival was 100%, 94.2%, and 95.8% (P = 0.25), and death‐censored graft survival was 94.9%, 94.7%, and 95.2% (P = 0.34) in AZA, MMF, and CsA groups, respectively. Mean estimated glomerular filtration rate was 70.4 ± 31.1, 60.1 ± 22.2, and 60.1 ± 19.0 ml/min/1.73 m2, respectively (P = 0.16). The incidence of biopsy‐proven acute rejection was 1.4%/year in the whole cohort. None of the patients developed polyomavirus‐associated nephropathy. The main cause of graft loss (n = 12) was chronic antibody‐mediated rejection (n = 6). De novo donor‐specific antibodies were detected in 13% of AZA‐, 21% of MMF‐, and 14% of CsA‐treated patients (P = 0.29). CsA monotherapy after 1 year is safe and associated with prolonged graft survival in well‐selected renal transplant recipient ( ClinicalTrials.gov number: 980654).  相似文献   
80.

Purpose

The use of laparoscopic sleeve gastrectomy (LSG) is increasing worldwide. Although post-LSG gastric stenosis (GS) is less frequent, it has not been well defined and lacks standardized management procedures. The objective of the present study was to describe a series of patients with GS symptoms after LSG and to develop a standardized management procedure for this complication.

Methods

We performed a retrospective analysis of a prospective database of patients presenting with GS after LSG procedures performed between January 2008 and March 2014. The primary efficacy criterion was the frequency of post-LSG GS. GS was classified as functional (i.e. a gastric twist) or organic. The secondary efficacy criteria included the time interval between LSG and diagnosis of GS, the type of stenosis, the type of management, and the follow-up data.

Results

During the study period, 1210 patients underwent primary or secondary LSG. Seventeen patients had post-operative symptoms of GS (1.4 %); one patient had achalasia that had not been diagnosed preoperatively and thus was excluded from our analysis. The median time interval between LSG and diagnosis of GS was 47.2 days (1–114). Eleven patients had organic GS and six had functional GS. Seven patients required nutritional support. Endoscopic treatment was successful in 15 patients (88.2 %) after balloon dilatation (n?=?13) or insertion of a covered stent (n?=?2). Two of the 15 patients required conversion to Roux-en-Y gastric bypass (11.8 %).

Conclusion

GS after LSG is a rare complication but requires standardized management. Most cases can be treated successfully with endoscopic balloon dilatation.
  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