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   8848篇
  免费   396篇
  国内免费   41篇
耳鼻咽喉   78篇
儿科学   129篇
妇产科学   102篇
基础医学   931篇
口腔科学   233篇
临床医学   575篇
内科学   2332篇
皮肤病学   253篇
神经病学   706篇
特种医学   312篇
外科学   1578篇
综合类   37篇
预防医学   172篇
眼科学   130篇
药学   627篇
  1篇
中国医学   14篇
肿瘤学   1075篇
  2024年   23篇
  2023年   68篇
  2022年   111篇
  2021年   187篇
  2020年   108篇
  2019年   154篇
  2018年   201篇
  2017年   145篇
  2016年   189篇
  2015年   188篇
  2014年   256篇
  2013年   312篇
  2012年   539篇
  2011年   559篇
  2010年   339篇
  2009年   294篇
  2008年   487篇
  2007年   493篇
  2006年   510篇
  2005年   591篇
  2004年   557篇
  2003年   514篇
  2002年   538篇
  2001年   139篇
  2000年   122篇
  1999年   142篇
  1998年   135篇
  1997年   115篇
  1996年   109篇
  1995年   76篇
  1994年   107篇
  1993年   62篇
  1992年   68篇
  1991年   70篇
  1990年   78篇
  1989年   91篇
  1988年   77篇
  1987年   73篇
  1986年   47篇
  1985年   46篇
  1984年   48篇
  1983年   38篇
  1982年   26篇
  1981年   22篇
  1980年   25篇
  1979年   30篇
  1978年   23篇
  1977年   21篇
  1974年   23篇
  1972年   19篇
排序方式: 共有9285条查询结果,搜索用时 15 毫秒
61.
ObjectivePrecursor lesions may be identified in fallopian tube tissue after risk-reducing salpingo-oophorectomy (RRSO) in patients with pathogenic variants of BRCA1/2. Serous tubal intraepithelial carcinoma (STIC) is considered a precursor of high-grade serous carcinoma, whereas the significance of the p53 signature remains unclear. In this study, we investigated the relationship between the p53 signature and the risk of ovarian cancer.MethodsWe analyzed the clinicopathological findings and conducted DNA sequencing for TP53 variants of p53 signatures and STIC lesions isolated using laser capture microdissection in 13 patients with pathogenic variants of BRCA1/2 who underwent RRSO and 17 control patients with the benign gynecologic disease.Results TP53 pathogenic variants were detected significantly higher in RRSO group than control (p<0.001). No difference in the frequency of p53 signatures were observed between groups (53.8% vs 29.4%; p=0.17). TP53 sequencing and next-generation sequencing analysis in a patient with STIC and occult cancer revealed 2 TP53 mutations causing different p53 staining for STICs and another TP53 mutation shared between STIC and occult cancer.ConclusionThe sequence analysis for TP53 revealed 2 types of p53 signatures, one with a risk of progression to STIC and ovarian cancer with pathological variants in TP53 and the other with a low risk of progression without pathological variants in TP53 as seen in control.  相似文献   
62.
An 89-year-old woman underwent examinations for leg edema. Blood tests indicated low nutrition and low pancreatic enzymes, and a stool examination indicated fatty stool. Computed tomography showed pleural effusion, ascites, and cystic lesions in the pancreatic head and mural nodules within the cysts. Pancreatic juice cytology revealed adenocarcinoma. The diagnosis was pancreatic exocrine insufficiency caused by intraductal papillary mucinous carcinoma. The patient did not wish to undergo surgery. Therefore, diuretics, component nutrients, and pancreatic exocrine replacement therapy using pancrelipase were initiated. After starting treatment, her leg edema, pleural effusion, and ascites disappeared, and her activities of daily living improved markedly.  相似文献   
63.
Surgery Today - Postoperative pneumonia affects the length of stay and mortality after surgery in elderly patients with colorectal cancer (CRC). We aimed to determine the risk factors of...  相似文献   
64.

Background

To investigate the expression of parathyroid hormone (PTH)/PTH-related peptide (PTHrP) receptor 1 (PTH1R) in clinical specimens of normal and diseased bladders. PTHrP is a unique stretch-induced endogenous detrusor relaxant that functions via PTH1R. We hypothesized that suppression of this axis could be involved in the pathogenesis of bladder disease.

Methods

PTH1R expression in clinical samples was examined by immunohistochemistry. Normal kidney tissue from a patient with renal cancer and bladder specimens from patients undergoing ureteral reimplantation for vesicoureteral reflux or partial cystectomy for urachal cyst were examined as normal control organs. These were compared with 13 diseased bladder specimens from patients undergoing bladder augmentation. The augmentation patients ranged from 8 to 31 years old (median 15 years), including 9 males and 4 females. Seven patients had spinal disorders, 3 had posterior urethral valves and 3 non-neurogenic neurogenic bladders (Hinman syndrome).

Results

Renal tubules, detrusor muscle and blood vessels in normal control bladders stained positive for PTH1R. According to preoperative urodynamic studies of augmentation patients, the median percent bladder capacity compared with the age-standard was 43.6% (range 1.5–86.6%), median intravesical pressure at maximal capacity was 30 cmH2O (range 10–107 cmH2O), and median compliance was 3.93 ml/cmH2O (range 0.05–30.3 ml/cmH2O). Detrusor overactivity was observed in five cases (38.5%). All augmented bladders showed negative stainings in PTH1R expression in the detrusor tissue, but positive staining of blood vessels in majority of the cases.

Conclusions

Downregulation of PTH1R may be involved in the pathogenesis of human end-stage bladder disease requiring augmentation.  相似文献   
65.
Background: Although the association between asthma control and body mass index (BMI) has been thoroughly investigated, most of this work has focused on the influence on asthma incidence or the effect of obesity on asthma control. To date, there have been no published studies on the influence of underweight on asthma control.Methods: The aim of this study was to investigate the influence of underweight, as defined by the Japan Society for the Study of Obesity (JASSO), on asthma control in Japanese asthmatic patients. Using data from questionnaire surveys administered by the Niigata Asthma Treatment Study Group, we compared asthma control, as measured by the Asthma Control Test (ACT), between a normal weight group (18.5 kg/m2 =< BMI < 25 kg/ m2) and an underweight group (BMI < 18.5 kg/m2).Results: Of the asthmatic patients who completed the 2008 and 2010 surveys, 1464 and 1260 cases were classified as being in the normal weight group, and 174 and 155 cases were classified as being in the underweight group. The ACT score (median, [interquartile range]) in the underweight group in 2008 (22, [19-24]) and 2010 (23, [19-25]) was significantly lower than that in the normal group in 2008 (23, [20-25]) and in 2010 (24, [21-25]).Conclusions: This study is the first, large-scale investigation of the influence of underweight on asthma control, and we have confirmed an adverse influence in a clinical setting. A potential mechanism for this interaction was unknown. Further investigation will be required.  相似文献   
66.
BACKGROUND: Decompensated hepatitis C virus (HCV)-related cirrhosis is the main indication for liver transplantation. We report the first successful living-related liver transplantation in a 49-year-old hemophilia A patient with end-stage HCV-related cirrhosis using a graft obtained from his 20-year-old daughter, an obligate carrier. METHODS: The donor's autologous fresh-frozen plasma rich in factor VIII (FVIII) by treatment with 1-deamino-8-D-arginine vasopressin was prepared before the operation. At induction, 1-deamino-8-D-arginine vasopressin was given to the donor to increase plasma FVIII level. In addition, autologous fresh-frozen plasma containing high FVIII concentrate was infused intraoperatively. The right lobe was harvested from the donor and transplanted orthotopically. The recipient was treated postoperatively with recombinant FVIII and immunosuppressive agents. RESULTS: The donor did not receive recombinant FVIII or allogenic blood during perioperative periods. No bleeding was encountered in the donor perioperatively. The recipient showed a steady increase in FVIII activity postoperatively and was discharged 40 days after transplantation. Ribavirin and interferon-alpha were provided for 3 months postoperatively to prevent potential recurrence of HCV infection. Serum HCV-RNA by RT-PCR became negative after such treatment. CONCLUSIONS: End-stage liver disease in patients with hemophilia A can be an indication for living-related liver transplantation. Furthermore, a graft from a living-related donor with hemophilia A carrier seems to be suitable provided such individuals receive adequate support for coagulopathies.  相似文献   
67.
68.
BACKGROUND: Local antigen presentation via either the oral (PO) or the portal venous (PV) routes results in suppression of systemic delayed-type hypersensitivity (DTH). The responsible cell populations are not well defined. Because NK1.1(+) T cells express the Fas ligand and produce high levels of the immunosuppressive cytokine, IL-4, they may play a role in both activated T-cell apoptosis and a Th1 to Th2 immune shift, thus promoting tolerance induction. METHODS: C57BL/6 mice were tolerized to BALB/c alloantigen by PV or PO spleen cells (25 x 10(6)) on Day 0. Subcutaneous (SQ) challenge with 10 x 10(6) BALB/c cells on Day 7 was followed by footpad injection of 10 x 10(6) BALB/c cells on Day 14. Footpad swelling was measured 24 h later. A single injection of the NK1.1(+) cell-depleting antibody, PK-136, was given IP (10 mg/kg) 2 days prior to PV or PO antigen. Flow cytometry evaluated NK1.1(+) cell depletion. CD1 knockout (KO) mice, lacking NK1.1(+) T cells, were also challenged with PV and PO Balb/c in parallel experiments. RESULTS: The DTH to BALB/c antigen was markedly suppressed in C57BL/6 mice when this alloantigen was given by either PO or PV routes (P < 0.001, P < 0.001). The maintenance of an unaltered response to third-party C3H/HeJ demonstrated alloantigenic specificity. Administration of the anti-NK1.1 T cell monoclonal antibody, PK-136, resulted in complete restoration of in vivo DTH responsiveness in PO tolerance (P < 0.01), and partial restoration in PV tolerance (P < 0.05) in C57BL/6 mice. FACS confirmed virtually complete depletion of liver, splenic, Peyer's patch, and mesenteric lymph node NK1.1(+) lymphocytes. Development of both PO and PV tolerance was prevented in CD1 KO mice. CONCLUSION: NK1.1(+) T cells play an essential role in antigen-specific suppression of the DTH response mediated by both oral and portal venous tolerance.  相似文献   
69.
We encountered a 75-year-old man who complained of exertional dyspnea. An echocardiographic examination showed aortic regurgitation and a tumor in the left ventricular outflow tract. Under complete extracorporeal circulation, we surgically made an incision of the ascending aorta with a slight thickening of the aortic valve and an enlarged annulus. After excising the aortic valve, an examination of the subvalvular region revealed mitral valve-like tissue extending from the annular region of the right coronary cusp to the ventricular septum, while the chordae tendinae was attached to the septum. This issue was excised, and the aortic valve was replaced with a 27-mm SJM valve. The postoperative course was uneventful, and the patient was discharged in good condition on postoperative day 30. An accessory mitral valve is extremely rare. Since this indication for surgical treatment is associated with congenital heart disease or a left ventricular outflow tract obstruction, most patients are young. Our patient had no associated cardiac anomalies and no pressure gradient attributable to a left ventricular outflow tract obstruction. This accessory mitral valve was discovered during aortic valve replacement surgery. To our knowledge, our patient is the oldest reported with an accessory mitral valve to have undergone a surgical resection.  相似文献   
70.
Cardiac amyloidosis may cause restrictive cardiomyopathy associated with heart failure, conduction disorder and ischemic heart disease. Therefore, patients with amyloidosis require careful hemodynamic monitoring in perioperative period. A 63-year-old man with cardiac amyloidosis was scheduled for pneumonectomy. His transthoracic echocardiography assessment showed a hypertrophic interventricular septum and slight decreased ejection fraction of 55%, but left ventricular (LV) diastolic function was decreased. Pulse Doppler for mitral valve inflow showed that the early peak velocity/atrial peak velocity (E/A) ratio was 0.9, the deceleration time (DT) was 163 msec and the early diastolic mitral annular tissue velocity (E') was 4 cm x sec(-1). These data suggested a pseudonormalization state. We performed careful monitoring using arterial pressure-based cardiac output (APCO), central venous oxygen saturation (ScvO2) and transesophageal echocardiography. There were no severe complications such as circulatory collapse and arrhythmia in the perioperative period.  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