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   2298篇
  免费   99篇
  国内免费   148篇
耳鼻咽喉   17篇
儿科学   34篇
妇产科学   18篇
基础医学   350篇
口腔科学   61篇
临床医学   219篇
内科学   572篇
皮肤病学   47篇
神经病学   183篇
特种医学   215篇
外科学   191篇
综合类   55篇
预防医学   125篇
眼科学   59篇
药学   179篇
中国医学   6篇
肿瘤学   214篇
  2023年   13篇
  2022年   23篇
  2021年   44篇
  2020年   27篇
  2019年   30篇
  2018年   44篇
  2017年   39篇
  2016年   40篇
  2015年   80篇
  2014年   91篇
  2013年   118篇
  2012年   166篇
  2011年   155篇
  2010年   120篇
  2009年   82篇
  2008年   107篇
  2007年   171篇
  2006年   151篇
  2005年   120篇
  2004年   115篇
  2003年   73篇
  2002年   54篇
  2001年   72篇
  2000年   53篇
  1999年   51篇
  1998年   55篇
  1997年   42篇
  1996年   33篇
  1995年   32篇
  1994年   37篇
  1993年   21篇
  1992年   24篇
  1991年   20篇
  1990年   19篇
  1989年   31篇
  1988年   32篇
  1987年   17篇
  1986年   13篇
  1985年   16篇
  1984年   7篇
  1983年   6篇
  1982年   7篇
  1981年   10篇
  1980年   11篇
  1978年   5篇
  1977年   8篇
  1976年   7篇
  1975年   8篇
  1972年   6篇
  1958年   14篇
排序方式: 共有2545条查询结果,搜索用时 15 毫秒
101.
Identifying potential modifiable risk factors to reduce the incidence of vascular access thrombosis in hemodialysis could reduce considerable morbidity and health care costs. We analyzed data from a subset of 1426 HEMO study subjects to determine whether more frequent intradialytic hypotension and/or lower predialysis systolic BP were associated with higher rates of vascular access thrombosis. Our primary outcome measure was episodes of vascular access thrombosis occurring within a given 6-month period during HEMO study follow-up. There were 2005 total episodes of vascular access thrombosis during a median 3.1 years of follow-up. The relative rate of thrombosis of native arteriovenous fistulas for the highest quartile of intradialytic hypotension was approximately twice that of the lowest quartile, independent of predialysis systolic BP and other covariates. There was no significant association of intradialytic hypotension with prosthetic arteriovenous graft thrombosis after multivariable adjustment. Higher predialysis systolic BP was associated with a lower rate of fistula and graft thrombosis, independent of intradialytic hypotension and other covariates. In conclusion, more frequent episodes of intradialytic hypotension and lower predialysis systolic BP associate with increased rates of vascular access thrombosis. These results underscore the importance of including vascular access patency in future studies of BP management in hemodialysis.  相似文献   
102.
AIM:To evaluate virological response to adefovir(ADV) monotherapy and emergence of ADV-resistant mutations in lamivudine(LAM)-resistant chronic hepatitis B patients.METHODS:Seventy-seven patients with documented LAM resistance who were treated with 10 mg/d ADV for>96 wk were analyzed for ADV resistance.RESULTS:At week 48 and 96,eight(10%)and 14(18%)of 77 LAM-resistant patients developed the ADV-resistant strain(rtA181V/T and/or rtN236T mutations),respectively.Hepatitis B virus(HBV)DNA levels during therapy ...  相似文献   
103.
Background/AimsBiliary complications including biliary strictures and bile leaks are the most common complications that occur after liver transplantation (LT). Endoscopic treatment with endoscopic retrograde cholangiography (ERC) is considered the first-line treatment, and percutaneous transhepatic cholangiography (PTC) can serve as an alternative or rescue therapy. However, nationwide clinical data on the frequency of ERC and PTC following LT have not yet been investigated.MethodsUsing the nationwide claims database, we investigated patients who underwent LT between 2012 and 2014 in Korea and followed them until 2015. We analyzed the prevalence and characteristics of patients and biliary procedures, including ERC and PTC implemented after LT.ResultsA total of 3,481 patients underwent LT during the 3-year study period. Among them, 3.0% of patients underwent biliary intervention postoperatively during the same hospitalization period, and 21.4% of patients received biliary intervention later on after initially being discharged from the hospital following LT. A total of 16.9% and 12.1% of patients underwent ERC and PTC after LT, respectively. The median period from LT to the first biliary intervention was 7.8 months (interquartile range, 3.5 to 14.6 months), and these patients underwent an average of 3.2±2.8 biliary procedures during the follow-up period. Patients undergoing living donor LT were more than twice as likely to undergo biliary procedures as those undergoing deceased donor LT (25.5% vs 12.1%).ConclusionsApproximately one-fourth of patients in Korea who underwent LT subsequently underwent ERC or PTC. Compared with deceased donor LT patients, those undergoing living donor LT underwent more biliary interventions and were more difficult to treat.  相似文献   
104.
105.
BACKGROUND AND AIMS: No information is available on the nature of the correlation between cyclooxygenase-2 (COX-2) expression and the clinicopathological features and prognosis of cholangiocarcinoma (CC). The goal of the present study was to determine the possible roles and clinical significance of COX-2 expression in CC. METHODS: We investigated the immunohistochemical expression of COX-2 in 102 patients with CC with respect to clinicopathological characteristics, namely evidence of Clonorchis sinensis infection, proliferation index (PI, assessed by Ki-67 expression), apoptotic index (AI, assessed by TUNEL stain), and microvessel density (MVD, assessed by CD34 expression). Evidence of C. sinensis infection was assessed by the microscopic examination of stools for C. sinensis ova, serological testing (ELISA), and the detection of peripheral bile duct dilations by imaging studies. RESULTS: An immunohistochemical investigation demonstrated the immunolabeling of tumor cells, mainly in the cytoplasmic and perinuclear regions, in 53 (52%) of the 102 patients with CC. No significant differences were found in terms of age, sex, tumor differentiation, involvement of the resection margin, presence of lymph nodes or liver metastases, or in pTNM stage between COX-2 positive and COX-2 negative patients. However, evidence of C. sinensis infection was more common in COX-2 positive patients (P < 0.05). No significant differences were found for PI, AI, MVD, or cumulative survival between COX-2 positive and COX-2 negative patients. CONCLUSION: Clonorchis sinensis infection is related to aberrant COX-2 expression in patients with CC. However, COX-2 expression is not related to clinical outcome in CC patients.  相似文献   
106.
AIM:To investigate the clinicopathologic parameters of pulmonary metastasis in colorectal cancer(CRC) patients after lung operation of indeterminate pulmonary nodules(IPNs).METHODS:From a prospective database of CRCpatients,40 cases that underwent lung operation between November 2008 and December 2012 for suspicious metastatic pulmonary nodules on chest computed tomography(CT)were enrolled.The decision to perform a lung operation was made if the patient met the following criteria:(1)completely resected or resectable primary CRC;(2)completely resectable IPNs;(3)controlled or controllable extrapulmonary metastasis;and(4)adequate general condition and pulmonary function to tolerate pulmonary operation.Lung operation was performed by a thoracic surgeon without CT-guided biopsy for pathologic confirmation.RESULTS:A total of 40 cases of lung resection was performed in 29 patients.Five patients underwent repeated lung resection.The final pathology result showed metastasis from the CRC in 30 cases(75%)and benign pathology in 10 cases(25%).The primary tumor site was the rectum in 26/30(86.6%)cases with pulmonary metastasis,but only 3/10(30%)cases in the benign group had a primary rectal cancer(P=0.001).Positron emission tomography(PET)-CT was performed for 22/30(73.4%)patients in the lung metastasis group and for 6/10(60.0%)patients in the benign group.PET-CT revealed hot uptake of18fluorine 2-fluoro-2-deoxy-D-glucose with all IPNs in both groups.The group with pulmonary metastasis had a higher incidence of primary rectal cancer(P=0.001),a more advanced tumor stage(P=0.011),and more frequent lymphatic invasion of tumor cells(P=0.005).Six cases with previous liver metastasectomy were present in the lung metastasis group.Serum carcinoembryonic antigen levels before lung operation were not elevated in any of the patients.CONCLUSION:The stage and location of the primary tumor and tumor cell infiltration of lymphatics provide useful indicators for deciding on lung resection of IPNs in CRC.  相似文献   
107.
In the present study, we evaluated the ophthalmologic outcomes of 24 patients who received chemotherapy and/or radiotherapy for the treatment of non-conjunctival ocular adnexal mucosa-associated lymphoid tissue-type (MALT) lymphoma. Ophthalmologic outcomes were assessed in patients who received chemotherapy and/or radiotherapy from March 2004 until May 2010. Outcomes were determined according to common symptoms following chemotherapy and/or radiotherapy, which consisted of decreased visual acuity, dry eye symptoms, retinopathy, optic neuropathy, increased intraocular pressure, and blepharitis. Nine patients received chemotherapy alone, eight patients received radiotherapy alone, and seven patients received chemotherapy with additional radiotherapy (chemoradiation therapy). Patients treated by chemotherapy alone showed better ophthalmologic outcome scores (mean score, 1.56) than those treated by radiation alone or chemoradiation therapy (mean score, 4.01). In conclusion, the treatment of ocular adnexal lymphoma including radiotherapy showed poor ophthalmologic outcomes due to radiation-induced complications. Recently, many new treatment options have emerged, such as immunotherapy or radioimmunotherapy. In the future study, to select a better treatment modality with fewer complications, well-designed prospective trials with ophthalmologic outcomes are needed.  相似文献   
108.
ABSTRACT

While the association between microbiomes and inflammatory bowel disease (IBD) is well known, establishing causal relationships between the two is difficult in humans. Germ-free (GF) mice genetically susceptible to IBD can address this question. Smad3-/- mice with defective transforming growth factor ß signaling are a model of IBD and colon cancer. They develop IBD upon colonization with Helicobacter under specific pathogen-free conditions, suggesting a role of the microbiome in IBD in this model. Thus, we rederived Smad3-/- mice GF to determine the potential of using these mice for testing the causative role of microbiomes in IBD. We found that fecal microbiomes from mice with IBD cause more severe gut inflammation in GF Smad3-/- and wild type mice compared to microbiomes from healthy mice and that Helicobacter induces gut inflammation within the context of other microbiomes but not by itself. Unexpectedly, GF Smad3+/+ and Smad3+/- mice given IBD microbiomes develop IBD despite their lack of disease in SPF conditions upon Helicobacter infection. This was not unique to the background strain of our Smad3 model (129); both wild type C57BL/6 and 129 strains developed IBD upon fecal transfer. However, wild type Swiss Webster stock was not susceptible, indicating that the genetic background of recipient mice influences the severity of IBD following fecal transfer. Our data suggest that the microbiome is an independent risk factor contributing to IBD development, and careful characterization of new GF models is needed to understand potential sources of confounding factors influencing microbiome studies in these mice.  相似文献   
109.
110.
Quinone oxidoreductase (NQO1) plays a key role in the cellular antioxidant defense by detoxifying quinine derivatives. Case-control association study of the possible relationship between the NQO1 gene polymorphism and mood disorders (patients with major depressive disorder, n=61; patients with bipolar I disorder, n=80; control, n=106) was carried out using PCR-based techniques. These preliminary results showed that the NQO1 gene polymorphism was not related to a susceptibility to mood disorders.  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