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   12898篇
  免费   819篇
  国内免费   68篇
耳鼻咽喉   137篇
儿科学   218篇
妇产科学   189篇
基础医学   1714篇
口腔科学   315篇
临床医学   1150篇
内科学   2835篇
皮肤病学   194篇
神经病学   1461篇
特种医学   756篇
外科学   2282篇
综合类   47篇
一般理论   2篇
预防医学   634篇
眼科学   300篇
药学   679篇
中国医学   13篇
肿瘤学   859篇
  2023年   126篇
  2022年   160篇
  2021年   313篇
  2020年   244篇
  2019年   312篇
  2018年   350篇
  2017年   323篇
  2016年   371篇
  2015年   422篇
  2014年   487篇
  2013年   686篇
  2012年   1010篇
  2011年   1064篇
  2010年   563篇
  2009年   548篇
  2008年   960篇
  2007年   938篇
  2006年   882篇
  2005年   796篇
  2004年   691篇
  2003年   648篇
  2002年   608篇
  2001年   115篇
  2000年   72篇
  1999年   88篇
  1998年   112篇
  1997年   99篇
  1996年   73篇
  1995年   62篇
  1994年   51篇
  1993年   56篇
  1992年   43篇
  1991年   40篇
  1990年   36篇
  1989年   42篇
  1988年   40篇
  1987年   28篇
  1986年   22篇
  1985年   26篇
  1984年   22篇
  1983年   32篇
  1982年   27篇
  1981年   26篇
  1980年   22篇
  1979年   12篇
  1978年   15篇
  1977年   14篇
  1976年   13篇
  1975年   12篇
  1974年   12篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
BACKGROUND: Dissimilarities in management and outcomes exist between upper tract urothelial carcinoma (UTUC) and urothelial carcinoma of the bladder (UCB). OBJECTIVE: The aim of this study was to analyze the stage-specific impact of upper or lower urinary tract tumor location on oncologic outcomes. DESIGN, SETTING, AND PARTICIPANTS: Data were collected from 4335 patients with UCB treated with radical cystectomy (RC) and bilateral pelvic lymphadenectomy (PLND), 877 patients with ureteral UTUC, and 1615 with pelvicalyceal UTUC treated with radical nephroureterectomy (RNU). No patient received preoperative chemotherapy or radiation therapy. INTERVENTIONS: Patients were treated with RC and bilateral PLND or RNU. MEASUREMENTS: Outcomes were assessed according to primary tumor location. RESULTS AND LIMITATIONS: Compared to UTUC patients, UCB patients had more advanced tumor stage and higher grade, and they were more likely to harbor lymphovascular invasion (LVI) and lymph node metastasis (p<0.001). In non-muscle-invasive tumor stages, UCB patients were more likely to experience disease recurrence and mortality compared to renal pelvicalyceal tumor patients (p<0.002) but not ureteral tumors (p>0.05). In pT2 and pT3 tumors, there was no difference in outcomes between the three tumor locations. In pT4 tumors, patients with ureteral and pelvicalyceal tumors were more likely to experience disease recurrence and mortality compared to UCB patients (p<0.004). These stage-specific findings were unchanged after adjustment for the effects of age, gender, tumor grade, LVI, lymph node status, and adjuvant chemotherapy. This study is limited by its retrospective and multicenter nature. CONCLUSIONS: Stage-specific differences in outcomes exist between UCB and UTUC. The differentially worse outcomes by stage between UCB and UTUC patients underline the differences between both cancer entities and the need for individualized stage-specific management for each patient.  相似文献   
103.
We analyzed the histologic features of peripheral nerve sheath tumors occurring in 14 patients with schwannomatosis. Among a total of 31 tumors, 19 tumors (61%) showed schwannoma-like nodules within a neurofibroma-like tumor, corresponding to hybrid neurofibroma/schwannoma. At least 1 hybrid tumor occurred in 10 of 14 (71%) schwannomatosis patients. We then retrieved cases of hybrid tumors without documented relation to schwannomatosis from our database and identified 41 tumors arising in 23 patients. More than half of these patients (14/23) were reported to suffer from multiple peripheral nerve sheath tumors, favoring a tumor syndrome. Indeed, analysis of clinical records revealed the diagnosis of neurofibromatosis type 2 (NF2) in 26% (6/23), neurofibromatosis type 1 (NF1) in 9% (2/23), definite schwannomatosis in 4% (1/23), and possible schwannomatosis in 13% (3/23) of patients with multiple nerve sheath tumors. Our findings suggest that hybrid neurofibroma/schwannoma represents a common tumor type in schwannomatosis and shows a striking association with neurofibromatoses.  相似文献   
104.

Background

ADPKD is one of the most common inherited disorders, with high risk for end-stage renal disease. Numerous patients, however, have no relatives in whom this disorder is known and are unsure whether they may transmit the disease to their offsprings. The aim of this study was to evaluate whether germline mutation analysis adds substantial information to clinical symptoms for diagnosis of ADPKD in these patients.

Methods

Clinical data included renal function and presence of liver or pancreas cysts, heart valve insufficiency, intracranial aneurysms, colonic diverticles, and abdominal hernias. Family history was evaluated regarding ADPKD. Germline mutation screening of the PKD1 and PKD2 genes was performed for intragenic mutations and for large deletions.

Results

A total of 324 adult patients with ADPKD including 30 patients without a family history of ADPKD (sporadic cases) were included. PKD1 mutations were found in 24/30 and PKD2 mutations in 6 patients. Liver cysts were present in 14 patients and intracranial aneurysms in 2 patients. Fourteen patients (45%) had no extrarenal involvement. Compared to the 294 patients with familial ADPKD, the clinical characteristics and the age at the start of dialysis were similar in those with sporadic ADPKD.

Conclusion

The clinical characteristics of patients with sporadic and familial ADPKD are similar, but sporadic ADPKD is often overlooked because of the absence of a family history. Molecular genetic screening for germline mutations in both PKD1 and PKD2 genes is essential for the definitive diagnosis of ADPKD.  相似文献   
105.

Purpose

To describe the natural history and identify predictors of cancer-specific survival in patients who experience disease recurrence after radical nephroureterectomy (RNU) for upper tract urothelial carcinoma (UTUC).

Methods

Of 2,494 UTUC patients treated with RNU without neoadjuvant chemotherapy, 597 patients experienced disease recurrence. A total of 148 patients (25?%) received adjuvant chemotherapy before disease recurrence. Multivariable Cox regression model addressed time to cancer-specific mortality after disease recurrence.

Results

The median time from RNU to disease recurrence was 12?months (interquartile range 5?C22). A total of 491 (82?%) of 597 patients died from UTUC, and 8 patients (1.3?%) died from other causes. The median time from disease recurrence to death of UTUC was 10?months. Actuarial cancer-specific survival estimate at 12?months after disease recurrence was 35?%. On multivariable analysis that adjusted for the effects of standard clinicopathologic characteristics, higher tumor stages [hazard ratio (HR) pT3 vs. pT0?CT1: 1.66, p?=?0.001; HR pT4 vs. pT0?CT1: 1.90, p?=?0.002], absence of lymph node dissection (HR 1.28, p?=?0.041), ureteral tumor location (HR 1.44, p?<?0.0005) and a shorter interval from surgery to disease recurrence (p?<?0.0005) were significantly associated with cancer-specific mortality. The adjusted 6-, 12- and 24-month postrecurrence cancer-specific mortality was 73, 60 and 57?%, respectively.

Conclusions

Approximately 80?% of patients who experience disease recurrence after RNU die within 2?years after recurrence. Patients with non-organ-confined stage, absence of lymph node dissection, ureteral tumor location and/or shorter time to disease recurrence died of their tumor more quickly than their counterparts. These factors should be considered in patient counseling and risk stratification for salvage treatment decision making.  相似文献   
106.
Fungal periprosthetic joint infections are a rare entity in orthopedic surgery, and there exist no guidelines according to which these infections can be successfully managed. Between 2004 and 2009, 7 patients with fungal periprosthetic joint infections (4 total hip arthroplasties and 3 total knee arthroplasties) have been treated with a 2-stage protocol and implantation of antibiotic-loaded cement spacers. Most of the infection was caused by Candida species. Systemic antifungal agents were administered for 6 weeks in 6 cases and 6 months in 1 case. The mean spacer implantation time was 12 weeks. At a mean follow-up of 28 months (5-70 months), no persistence of infection or reinfection could be observed. A 2-stage treatment protocol with implantation of an antibiotic-loaded cement spacer is an efficient option in the treatment of fungal periprosthetic infections.  相似文献   
107.
BACKGROUND: Graft pancreatitis is a major complication after pancreas transplantation. Antithrombin III (AT III) is an anticoagulatory and anti-inflammatory substance. The aim of our study was to evaluate a prophylactic application of AT III in experimental pancreas transplantation. METHODS: Pancreas transplantation was performed in rats. Cold ischemia time (University of Wisconsin solution at 4 degrees C) was 12 hours. After 4 hours of reperfusion, pancreatic enzymes were assessed and the pancreas was evaluated by intravital microscopy and histologic and immunohistochemical examination. Recipients were allocated randomly to 2 groups: 1 control group (n = 6) and 1 group in which recipients received 125 IU AT III/kg 30 minutes before reperfusion (n = 6). Six animals that did not undergo transplantation served as healthy controls. RESULTS: Enzyme levels showed no differences between the 2 transplantation groups but were significantly (P <.05) higher than in the control group. Histologic damage was significantly less evident in animals that received AT III compared with transplantation animals that did not receive AT III. During intravital microscopy, animals receiving AT III showed significantly higher capillary and venular erythrocyte velocities compared with untreated transplantation animals. The leukocyte-endothelium interaction in postcapillary venules was decreased significantly in animals with AT III treatment. CONCLUSIONS: AT III pretreatment decreases tissue damage by attenuating microcirculatory disturbances and leukocyte adherence in experimental graft pancreatitis by its anti-inflammatory and anticoagulatory properties.  相似文献   
108.
ObjectiveThe aim of this prospective study was to determine whether the additional use of the single photon emission computed tomography/CT (SPECT/CT) technique improves the diagnostic value of planar lymphoscintigraphy in patients presenting with primary lymph edema of the lower limb.ResultsIn comparison to pathological planar scintigraphic findings, the addition of SPECT/CT provided relevant additional information regarding the presence of dermal backflow (86%), the anatomical extent of lymphatic disorders (64%), the presence or absence of lymph nodes (46%), and the visualization of lymph vessels (4%).ConclusionAs an adjunct to planar lymphoscintigraphy, SPECT/CT specifies the anatomical correlation of lymphatic disorders and thus improves assessment of the extent of pathology due to the particular advantages of tomographic separation of overlapping sources. The interpretation of scintigraphic data benefits not only in baseline diagnosis, but also in physiotherapeutical and microsurgical treatments of primary lymphedema.  相似文献   
109.
110.
Objective: Standard treatment of patients with infective endocarditis is radical debridement and valve replacement, in cases with advanced pathology the treatment is usually root replacement with either a composite graft or a homograft. Enthusiasm for the use of the Ross operation in non-infective aortic valve disease is increasing, but use of the pulmonary autograft in the treatment of aortic valve endocarditis has been limited. The objective of this prospective study is to present the technique and results of our experience with aortic valve endocarditis treated with the Ross operation. Materials and methods: Since 1992 we have treated 35 patients (median age 41 years, range 6–71 years) having aortic valve endocarditis with a Ross operation. Twenty-four patients had advanced disease defined as pathology due to endocarditis extending beyond the valve cusps (13 patients) or prosthetic valve endocarditis (11 patients). Twenty-two patients had active disease at the time of surgery, and 12 had undergone one to four previous heart operations. Results: There were two operative deaths (5.8%), both related to severe disease with very advanced pathology and heart failure. Intraoperative echocardiography demonstrated no or trivial autograft insufficiency in all patients. There have been no late deaths. There has been one (probable) recurrent right-sided endocarditis in a drug addict during a follow-up period of 3–56 months. One patient has been reoperated on for homograft stenosis. Conclusions: We are enthusiastic about the use of the Ross operation in aortic valve endocarditis and in younger patients with advanced pathology, it is our preferred treatment modality. Following removal of the autograft, unparalleled exposure of the left ventricular outflow tract is obtained. Even in patients with very advanced pathology the left ventricular outflow tract is usually intact, allowing autograft implantation in the standard fashion. For selected patients with simple endocarditis, the Ross operation is an attractive option on its usual merits.  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