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   2036篇
  免费   147篇
  国内免费   11篇
耳鼻咽喉   25篇
儿科学   48篇
妇产科学   29篇
基础医学   331篇
口腔科学   30篇
临床医学   157篇
内科学   494篇
皮肤病学   65篇
神经病学   192篇
特种医学   38篇
外科学   213篇
综合类   13篇
预防医学   92篇
眼科学   23篇
药学   187篇
中国医学   3篇
肿瘤学   254篇
  2024年   3篇
  2023年   32篇
  2022年   42篇
  2021年   72篇
  2020年   39篇
  2019年   52篇
  2018年   58篇
  2017年   50篇
  2016年   66篇
  2015年   64篇
  2014年   77篇
  2013年   101篇
  2012年   148篇
  2011年   187篇
  2010年   94篇
  2009年   73篇
  2008年   141篇
  2007年   157篇
  2006年   128篇
  2005年   132篇
  2004年   130篇
  2003年   117篇
  2002年   96篇
  2001年   12篇
  2000年   6篇
  1999年   13篇
  1998年   27篇
  1997年   13篇
  1996年   12篇
  1995年   6篇
  1994年   2篇
  1993年   9篇
  1992年   5篇
  1991年   3篇
  1990年   5篇
  1988年   2篇
  1987年   3篇
  1986年   1篇
  1984年   3篇
  1983年   1篇
  1982年   1篇
  1979年   1篇
  1978年   2篇
  1977年   1篇
  1975年   4篇
  1972年   1篇
  1971年   1篇
  1968年   1篇
排序方式: 共有2194条查询结果,搜索用时 15 毫秒
71.
A case of extensive extra-and intrahepatic portal tumor thrombosis, with no metastatic foci in liver parenchyma, secondary to advanced gastric carcinoma in a 69-year-old man is reported. The portal tumor thrombosis was characterized by enlargement of the thrombosed segment of the vein, decreased density mass without intraluminal enhancement of the involved vein, nonvisualization of the portal venous branch in the involved lobe, and the so-called cavernous transformation of the portal vein. The surgically resected gastric specimen showed Borrmann type 3 advanced papillary adenocarcinoma. The portal tumor thrombus is presumed to have arisen from vascular invasion in the primary foci of gastric carcinoma, and then to have permeated the portal vein without invasion of liver parenchyma.  相似文献   
72.
73.
74.

Background

Narrow-band imaging (NBI) has been confirmed as a useful endoscopic technique to distinguish neoplasm from normal tissue, on the basis of the enhanced neovascularity of tumor tissue. NBI-guided tissue biopsy for laryngopharyngeal and digestive lesions is a novel methodology, but the feasibility for central nervous system tumors remains unclear. The aim of our study was to evaluate the feasibility of NBI-guided biopsy for intraventricular and paraventricular tumor.

Methods

Fourteen patients with intraventricular or paraventricular tumors underwent neuroendoscopic biopsy using a videoscope with NBI. Ventricular walls and tumors were observed using conventional imaging, followed by NBI. Colors of ventricle walls and tumors visualized using NBI were compared to those visualized under conventional imaging. Extracted specimens were stained using CD31 antibody and numbers of microvessels in each specimen were counted for analyzing vascular density.

Results

Normal ventricle walls were a similar color under conventional imaging and NBI. Tumor surfaces appeared to be cyan in color under NBI. Vessels on the tumor were more clearly visualized with NBI than with conventional imaging. NBI was able to identify tumor surfaces that were not perceptible on conventional imaging. All specimens in the lesion surfaces from cyan-colored areas under NBI contained tumor cells. Specimens extracted from regions that appeared cyan in color under NBI (51.0 vessels/mm2) had significantly greater vascular density than regions that appeared a normal color (17.4 vessels/mm2; p = 0.039).

Conclusion

NBI-guided biopsy of intraventricular and paraventricular tumors is feasible for visualizing tumor surface-enhancing neovascularities. NBI would contribute to accurate histological diagnosis while minimizing injury to surrounding structures.  相似文献   
75.
There is limited information in the use of antitumor necrosis factor α, infliximab, in patients on hemodialysis. In Crohn’s disease (CD), only 3 cases are reported.A 76-year-old man on hemodialysis for renal failure caused by immunoglobulin A nephropathy developed diarrhea and abdominal pains. A marked edema was observed in the pretibia and ankle. An increase of C-reactive protein (CRP) and erythrocyte sedimentation rate, hypoalbuminemia, hypocholesterolemia, and moderate anemia was found. Ultrasonography and computed tomography (CT) found wall thickness in the left colon. Sigmoidoscopy revealed multiple ulcers in the sigmoid colon and noncaseating epithelioid granuloma was found in the biopsy specimen. Barium enema study exhibited collar button signs and longitudinal ulcers in the left colon.A severe form of CD was diagnosed. Metronidazole seemed to decrease CRP but was ineffective in ameliorating diarrhea. Infliximab rather than steroid hormone was chosen for the treatment. Standard induction therapy with infliximab was initiated. Symptoms rapidly improved then disappeared. CD activity index decreased from 747 to a remission level of 134 after 2 infusions of infliximab. Scheduled maintenance infliximab therapy was administered after the induction therapy. Ultrasonography and CT showed a disappearance of the wall thickness of the colon. Adverse reactions were not observed.Infliximab was effective and safe in a patient with CD on hemodialysis. Our case has added additional literature in accordance with previous reports supporting infliximab as effective and safe in patients on hemodialysis.  相似文献   
76.

Background

Cervical intraepithelial neoplasia grade 3 (CIN3) is a mucosal precancerous lesion caused by high-risk human papillomavirus (HPV). Induction of immunological clearance of CIN3 by targeting HPV antigens is a promising strategy for CIN3 therapy. No successful HPV therapeutic vaccine has been developed.

Methods

We evaluated the safety and clinical efficacy of an attenuated Lactobacillus casei expressing modified full-length HPV16 E7 protein in patients with HPV16-associated CIN3. Ten patients were vaccinated orally during dose optimization studies (1, 2, 4, or 6 capsules/day) at weeks 1, 2, 4, and 8 (Step 1). Seven additional participants were only tested using the optimized vaccine formulation (Step 2), giving a total of 10 patients who received optimized vaccination. Cervical lymphocytes (CxLs) and peripheral blood mononuclear cells (PBMCs) were collected and E7 specific interferon-γ-producing cells were counted (E7 cell-mediated immune responses: E7-CMI) by ELISPOT assay. All patients were re-evaluated 9 weeks after initial vaccine exposure using cytology and biopsy to assess pathological efficacy.

Results

No patient experienced an adverse event. E7-CMI in both CxLs and PBMCs was negligible at baseline. All patients using 4–6 capsules/day showed increased E7-CMI in CxLs, whereas patients using 1–2 capsules/day did not. No patient demonstrated an increase in E7-CMI in their PBMCs. In comparison between patients of cohorts, E7-CMI at week 9 (9 wk) in patients on 4 capsules/day was significantly higher than those in patients on 1, 2, or 6 capsules/day. Most patients (70%) taking the optimized dose experienced a pathological down-grade to CIN2 at week 9 of treatment. E7-CMI in CxLs correlated directly with the pathological down-grade.

Conclusions

Oral administration of an E7-expressing Lactobacillus-based vaccine can elicit E7-specific mucosal immunity in the uterine cervical lesions. We are the first to report a correlation between mucosal E7-CMI in the cervix and clinical response after immunotherapy in human mucosal neoplasia.  相似文献   
77.
78.
79.
80.
The programmed cell death 1 (PD1)/PD1 ligand (PD-L1) axis plays an important role in tumor cell escape from immune control and has been most extensively investigated for therapeutic purposes. However, PD-L1 immunohistochemistry is still not used widely for diagnosis. We review the diagnostic utility of PD-L1 (by clone SP142) immunohistochemistry in large-cell lymphomas, mainly consisting of classic Hodgkin lymphoma (CHL) and diffuse large B-cell lymphoma (DLBCL). Neoplastic PD-L1 (nPD-L1) expression on Hodgkin and Reed-Sternberg cells is well-established among prototypic CHL. Of note, EBV+ CHL often poses a challenge for differential diagnosis from peripheral T-cell lymphoma with EBV+ non-malignant large B-cells; their distinction is based on the lack of PD-L1 expression on large B-cells in the latter. The nPD-L1 expression further provides a good diagnostic consensus for CHL with primary extranodal disease conceivably characterized by a combined pathogenesis of immune escape of tumor cells and immunodeficiency. Compared with CHL, the nPD-L1 expression rate is much lower in DLBCL, highlighting some specific subgroups of intravascular large B-cell lymphoma, primary mediastinal large B-cell lymphoma, and EBV+ DLBCL. They consist of nPD-L1-positive and -negative subgroups, but their clinicopathological significance remains to be elucidated. Microenvironmental PD-L1 positivity on immune cells may be associated with a favorable prognosis in extranodal DLBCL. PD-L1 (by SP142) immunohistochemistry has helped us to understand the immune biology of lymphoid neoplasms possibly related by immune escape and/or immunodeficiency. However, knowledge of these issues remains limited and should be clarified for diagnostic consensus in the future.  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