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   5276篇
  免费   266篇
  国内免费   33篇
耳鼻咽喉   53篇
儿科学   77篇
妇产科学   77篇
基础医学   603篇
口腔科学   112篇
临床医学   295篇
内科学   1604篇
皮肤病学   146篇
神经病学   384篇
特种医学   222篇
外科学   839篇
综合类   22篇
预防医学   101篇
眼科学   66篇
药学   356篇
中国医学   27篇
肿瘤学   591篇
  2023年   33篇
  2022年   58篇
  2021年   119篇
  2020年   74篇
  2019年   79篇
  2018年   114篇
  2017年   100篇
  2016年   120篇
  2015年   136篇
  2014年   153篇
  2013年   177篇
  2012年   339篇
  2011年   386篇
  2010年   203篇
  2009年   189篇
  2008年   324篇
  2007年   347篇
  2006年   318篇
  2005年   323篇
  2004年   316篇
  2003年   367篇
  2002年   324篇
  2001年   71篇
  2000年   40篇
  1999年   78篇
  1998年   72篇
  1997年   46篇
  1996年   61篇
  1995年   44篇
  1994年   70篇
  1993年   39篇
  1992年   58篇
  1991年   42篇
  1990年   35篇
  1989年   28篇
  1988年   28篇
  1987年   43篇
  1986年   13篇
  1985年   21篇
  1984年   15篇
  1983年   7篇
  1982年   22篇
  1981年   16篇
  1980年   16篇
  1979年   15篇
  1978年   8篇
  1977年   18篇
  1975年   7篇
  1971年   6篇
  1970年   6篇
排序方式: 共有5575条查询结果,搜索用时 15 毫秒
101.
102.
Birt-Hogg-Dubé (BHD) syndrome is an autosomal dominant disorder characterized by cutaneous fibrofolliculomas, pulmonary cysts, and kidney malignancies. Affected individuals carry germ line mutations in folliculin (FLCN), a tumor suppressor gene that becomes biallelically inactivated in kidney tumors by second-hit mutations. Similar to other factors implicated in kidney cancer, FLCN has been shown to modulate activation of mammalian target of rapamycin (mTOR). However, its precise in vivo function is largely unknown because germ line deletion of Flcn results in early embryonic lethality in animal models. Here, we describe mice deficient in the newly characterized folliculin-interacting protein 1 (Fnip1). In contrast to Flcn, Fnip1(-/-) mice develop normally, are not susceptible to kidney neoplasia, but display a striking pro-B cell block that is entirely independent of mTOR activity. We show that this developmental arrest results from rapid caspase-induced pre-B cell death, and that a Bcl2 transgene reconstitutes mature B-cell populations, respectively. We also demonstrate that conditional deletion of Flcn recapitulates the pro-B cell arrest of Fnip1(-/-) mice. Our studies thus demonstrate that the FLCN-FNIP complex deregulated in BHD syndrome is absolutely required for B-cell differentiation, and that it functions through both mTOR-dependent and independent pathways.  相似文献   
103.
Assessment of liver fibrosis in patients with chronic hepatitis C (CHC) is critical for predicting disease progression and determining future antiviral therapy. LecT-Hepa, a new glyco-marker derived from fibrosis-related glyco-alteration of serum alpha 1-acid glycoprotein, was used to differentiate cirrhosis from chronic hepatitis in a single-center study. Herein, we aimed to validate this new glyco-marker for estimating liver fibrosis in a multicenter study. Overall, 183 CHC patients were recruited from 5 liver centers. The parameters Aspergillus oryzae lectin (AOL) / Dature stramonium lectin (DSA) and Maackia amurensis lectin (MAL)/DSA were measured using a bedside clinical chemistry analyzer in order to calculate LecT-Hepa levels. The data were compared with those of seven other noninvasive biochemical markers and tests (hyaluronic acid, tissue inhibitor of metalloproteases-1, platelet count, aspartate aminotransferase-to-platelet ratio index [APRI], Forns index, Fib-4 index, and Zeng's score) for assessing liver fibrosis using the receiver-operating characteristic curve. LecT-Hepa correlated well with the fibrosis stage as determined by liver biopsy. The area under the curve (AUC), sensitivity, and specificity of LecT-Hepa were 0.802, 59.6%, and 89.9%, respectively, for significant fibrosis; 0.882, 83.3%, and 80.0%, respectively, for severe fibrosis; and 0.929, 84.6%, and 88.5%, respectively, for cirrhosis. AUC scores of LecT-Hepa at each fibrosis stage were greater than those of the seven aforementioned noninvasive tests and markers. Conclusion: The efficacy of LecT-Hepa, a glyco-marker developed using glycoproteomics, for estimating liver fibrosis was demonstrated in a multicenter study. LecT-Hepa given by a combination of the two glyco-parameters is a reliable method for determining the fibrosis stage and is a potential substitute for liver biopsy. (HEPATOLOGY 2012).  相似文献   
104.
105.
We report a 72-year-old man with respiratory involvement of immunoglobulin G4 (IgG4)-related disease, who developed dry cough and shortness of breath on effort. The chest computed tomography scan image showed massive and diffuse ground-glass opacity, interlobular thickening, and bronchial wall thickening. The infiltration of IgG4-positive plasma cells in the transbronchial lung biopsy and high serum IgG4 concentrations were found. The patient was treated with 0.6?mg/kg oral prednisolone and showed rapid improvement. This is a case of IgG4-related disease in which the only complication was respiratory involvement.  相似文献   
106.
Purpose

To report abnormal full-field electroretinograms (ERGs) in a patient with cystoid macular edema (CME) induced by systemic paclitaxel.

Methods

This is an observational case report. Full-field ERGs were recorded to evaluate the retinal function using the RETeval system and conventional ERGs using contact lens electrodes with built-in white light-emitting diodes. Optical coherence tomography (OCT) was also used to assess the retinal morphology.

Results

A 70-year-old man, who was diagnosed with gastric cancer, had undergone gastrectomy. Subsequently, systemic paclitaxel was administered once a week as an adjuvant therapy. After the tenth course of paclitaxel, he experienced blurred vision in both eyes and visited our department of ophthalmology. OCT revealed the presence of CME in both eyes, and the RETeval flicker ERGs showed a marked reduction in the amplitudes and a prolongation of the implicit times in both eyes. Conventional ERGs showed that the amplitudes of the oscillatory potentials (OPs) were also severely attenuated. The abnormal OCT findings and reduced visual acuity recovered to normal at 1 and 2 months, respectively, after the discontinuation of paclitaxel. However, the flicker ERGs did not recover to normal values until 4 months after the discontinuation of paclitaxel.

Conclusion

These results suggest that the ERGs can be used to monitor the changes in the overall retinal function in patients receiving paclitaxel.

  相似文献   
107.
108.

Background

We retrospectively investigated prognostic factors to be used in selecting the patients with stage IV gastric cancer (GC) who have an unfavorable prognosis after palliative gastrectomy.

Methods

A total of 146 GC patients at stage IV who had undergone palliative gastrectomy were enrolled. Various clinicopathological parameters were evaluated for prognosis.

Results

Surgical morbidity and hospital mortality occurred in 35 (23.9 %) and 4 (2.7 %) patients, respectively. The overall 5-year survival rate and the median survival time were 11.2 % and 13.2 months, respectively. Of the 146 patients, 64 had uncomfortable symptoms associated with GC and 76 had no such symptoms. Of the 64 patients with uncomfortable symptoms, 60 (93.7 %) experienced relief of these symptoms after palliative surgery. Multivariate analysis for patients without uncomfortable symptoms associated with GC revealed that the number of incurable factors and serum SPan-1 level were independent prognostic factors.

Conclusions

Patients with stage IV GC who had multiple incurable factors and a high level of serum SPan-1 might not be candidates for palliative gastrectomy for the purpose of prognostic benefit.  相似文献   
109.
110.
Alpha2-macroglobulin is a protease inhibitor that enhances procoagulant properties via the neutralization of plasmin, plasminogen activators and metalloproteinases. Additionally, alpha2-macroglobulin is thought to be involved in inflammatory reactions as a carrier protein for interleukin-6 (IL-6). The objective of this study was to evaluate the usefulness of alpha2-macroglobulin as a biomarker for cerebrovascular diseases. Patients with acute ischemic stroke (n = 159; 93 male and 66 female, 71.6 ± 10.3 years) and patients with no previous history of stroke (n = 77; 38 male and 39 female, 70.7 ± 9.5 years) were consecutively enrolled in this study. White matter lesions were assessed via the fluid-attenuated inversion recovery image of magnetic resonance images using the Fazekas classification. The serum alpha2-macroglobulin levels were measured by nephelometry. The serum alpha2-macroglobulin levels at admission in patients with acute ischemic stroke were higher than those in the control patients (230.2 ± 73.7 vs. 205.0 ± 55.8 mg/dl, p = 0.009). The serum alpha2-macroglobulin levels were positively correlated with age and the severity of the white matter lesions (R 2 = 0.048, p < 0.001 and R 2 = 0.058, p < 0.001, respectively), although there was no significant association between serum alpha2-macroglobulin levels and IL-6 levels. In addition, multivariate analysis showed that increased serum alpha2-macroglobulin levels were independently associated with the severity of white matter lesions [standardized partial regression coefficient (β) 0.102, p = 0.026]. Increased serum alpha2-macroglobulin levels might be involved in the pathophysiology of acute ischemic stroke. Furthermore, serum alpha2-macroglobulin levels, which were associated with high-grade white matter lesions, may reflect the chronic pathophysiological condition of cerebral small vessel disease.  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