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   1621篇
  免费   64篇
  国内免费   4篇
耳鼻咽喉   7篇
儿科学   61篇
妇产科学   53篇
基础医学   237篇
口腔科学   36篇
临床医学   164篇
内科学   265篇
皮肤病学   73篇
神经病学   127篇
特种医学   57篇
外科学   162篇
综合类   23篇
一般理论   3篇
预防医学   117篇
眼科学   33篇
药学   130篇
中国医学   14篇
肿瘤学   127篇
  2024年   16篇
  2023年   22篇
  2022年   52篇
  2021年   75篇
  2020年   50篇
  2019年   62篇
  2018年   81篇
  2017年   57篇
  2016年   61篇
  2015年   45篇
  2014年   71篇
  2013年   99篇
  2012年   117篇
  2011年   124篇
  2010年   76篇
  2009年   70篇
  2008年   81篇
  2007年   72篇
  2006年   85篇
  2005年   75篇
  2004年   72篇
  2003年   55篇
  2002年   53篇
  2001年   11篇
  2000年   14篇
  1999年   6篇
  1998年   7篇
  1997年   5篇
  1996年   8篇
  1995年   10篇
  1994年   2篇
  1993年   6篇
  1992年   5篇
  1991年   7篇
  1990年   4篇
  1989年   4篇
  1988年   2篇
  1986年   2篇
  1985年   2篇
  1984年   2篇
  1983年   3篇
  1982年   3篇
  1980年   2篇
  1976年   1篇
  1975年   1篇
  1974年   1篇
  1973年   3篇
  1971年   1篇
  1969年   1篇
  1968年   2篇
排序方式: 共有1689条查询结果,搜索用时 0 毫秒
141.
BackgroundAcetamiprid (ACMP) is a member of the neonicotinoid group of insecticides. It is extensively used worldwide. The misuse of ACMP creates danger hazards to human and animal.MethodsACMP induced renal damage evidenced by an increase in kidney injury biomarkers. So the goal of this work is to clarify the reno protective effect of Quercetin (Qrctn) and/or Nano-glutathione (N-Gluta) solely or in combination to counterbalance the danger effect of ACMP. All treatments with the previous agents were coadministered orally with ACMP for one month.ResultsACMP ingestion caused a significant rise in serum creatinin, urea, and uric acid, TNF α along with renal cystatin C, lipid peroxidation and nitric oxide with the concomitant decline in the levels of reduced glutathione and IL-10 levels. Protein expression of ICAM was upregulated as well as mRNA expression of NF-κB while mRNA expression of Nrf2 was down-regulated. Immune histochemistry of TLR 4 revealed strong immune reaction. The administration of Qrctn or N-Gluta either individually or together modulated all the preceding aforementioned parameters.ConclusionFascinatingly Qrctn and N-Gluta combination was the most powerful regimen to frustrate ACMP reno-toxicity and may be deliberate as a hopeful applicant for renal therapy.  相似文献   
142.
The radioprotective effect of silymarin using different modes of treatment against radiation (3 or 6 Gy) induced hepatotoxicity 1, 3 and 7 days post-irradiation was studied. Whole-body gamma-irradiation revealed an increase in serum alkaline phosphatase (AP) activity as well as liver glutathione reductase (GR) and glutathione peroxidase (GSH-PX) activities on the first post-exposure day with respect to the control value. However, 3 days after radiation exposure, these parameters showed a significant decrease below the control level which persisted till the end of the experimental time except for serum AP activity that showed another increase on the seventh post-exposure day at 3 Gy dose of radiation. A gradual increase in serum alanine and aspartate aminotransferase (ALT&AST) as well as gamma glutamyl transpeptidase activities were observed due to irradiation throughout the experimental time. Administration of silymarin as single (70 mg kg (-1)), fractionated (490 mg kg (-1)) oral doses or as intravenous (i.v.) injection (50 mg kg (-1)), caused significant protection. Intravenous treatment showed the most pronounced protection. The protective effect of silymarin was attributed to its antioxidant and free radicals scavenging properties.  相似文献   
143.
An oxidimetric titrant, 2,3-dichloro-5,6-dicyano-1,4-benzoquinone in anhydrous acetic acid is used for the semimicro-determination of hydrazine hydrate, phenylhydrazine hydrochloride, isoniazid and iproniazid phosphate in pure forms as well as in some pharmaceutical preparations containing isoniazid and iproniazid phosphate. The end point was detected potentiometrically using a platinum-calomel combination electrode. The results obtained are compared statistically with those obtained by the official methods and they are in good agreement.  相似文献   
144.

Background

The purpose of this study was to investigate whether localized peripheral inflammation, such as osteoarthritis, contributes to neuroinflammation and neurodegenerative disease in vivo.

Methods

We employed the inducible Col1-IL1βXAT mouse model of osteoarthritis, in which induction of osteoarthritis in the knees and temporomandibular joints resulted in astrocyte and microglial activation in the brain, accompanied by upregulation of inflammation-related gene expression. The biological significance of the link between peripheral and brain inflammation was explored in the APP/PS1 mouse model of Alzheimer's disease (AD) whereby osteoarthritis resulted in neuroinflammation as well as exacerbation and acceleration of AD pathology.

Results

Induction of osteoarthritis exacerbated and accelerated the development of neuroinflammation, as assessed by glial cell activation and quantification of inflammation-related mRNAs, as well as Aβ pathology, assessed by the number and size of amyloid plaques, in the APP/PS1; Col1-IL1βXAT compound transgenic mouse.

Conclusion

This work supports a model by which peripheral inflammation triggers the development of neuroinflammation and subsequently the induction of AD pathology. Better understanding of the link between peripheral localized inflammation, whether in the form of osteoarthritis, atherosclerosis or other conditions, and brain inflammation, may prove critical to our understanding of the pathophysiology of disorders such as Alzheimer's, Parkinson's and other neurodegenerative diseases.  相似文献   
145.
Ascites from seven patients with advanced cancer were studied to characterize the kininogens. Immunological quantification of low molecular weight kininogen (L-kininogen) and high molecular weight kininogen (H-kininogen) by rocket immunoelectrophoresis showed values of 42% and 39%, respectively, compared to control plasma. Release of kinin from the ascites samples was assayed on an isolated rat uterus. The total kinin released from the kininogens was 39% of the value in control plasma, while release selectively from H-kininogen amounted to 25% of plasma. This indicates about 30% of the bradykinin in H-kininogen to be released in vivo in ascites, and points to kinins as possible mediators of the increased vascular permeability causing accumulation of ascites. The function of kininogens as cysteine protease inhibitors (CPIs) was assayed as well, indicating that both L- and H-kininogen function as cysteine protease inhibitors in human ascitic fluid. The proteolytic cleavage of H-kininogen in ascites was studied by polyacrylamide gel electrophoresis and subsequent immunoblotting. H-kininogen was extensively cleaved in ascites compared to control plasma, with large amounts present of a degraded form with Mr of 99 kDa. The bands observed compared well with those described in plasma, and are consistent with contact activation taking place in ascites.  相似文献   
146.
With a view to investigating whether in circadian variations of platelet aggregation (PA) and fibrinolytic activity there is an elevated risk period for incidence and development of ischemic stroke, 25 healthy subjects (5 females and 20 males), their age ranging from 29 to 51, were exposed to the analysis of PA, euglobulin lysis time (ELT), fibrinogen degradation products (FDP), antithrombin III (AT III) and heparin tolerance test (HTT) in blood samples drawn by venepuncture at 08.00, 11.00, 13.00, 15.00, 17.00 and 18.00 h; beside these intervals in the case of 10 healthy males, whose age ranged from 32 to 45, blood samples were taken at midnight as well. The group of 25 subjects comprised those who usually worked daily and nightly shifts, as well as those who were either at bed rest or doing their duties during daytime. The findings of this investigation have demonstrated that all the parameters studied exhibited circadian variations irrespective of sex, age or daily/nightly activities of the subjects. The most pronounced PA interval, which was not accompanied by corresponding increase of fibrinolytic activity, was that around 11.00 h and it is marked as the highest risk period for onset of ischemic stroke.  相似文献   
147.
148.
OBJECTIVES: To assess the association between non-severe liver enzyme elevations (LEEs) during antiretroviral treatment and liver fibrosis in HIV/HCV-coinfected patients. METHODS: All co-infected patients from an Infectious Disease Unit who had received treatment with highly active antiretroviral therapy (HAART) for at least 12 months before undergoing a liver biopsy were included in the study. RESULTS: One-hundred and sixteen patients met the inclusion criteria of the study. Advanced liver fibrosis was observed in 32 (38%) of 84 patients who developed non-severe LEEs and in 11 (34%) of 32 subjects who developed severe (grade > or = 3) LEEs, (P = 0.7). Seven (6%) of 116 patients showed grade 3 or 4 LEEs for at least 30% of the follow-up. Advanced liver fibrosis was observed in five (71%) of these patients and in 38 (35%) of the 109 subjects who did not develop long-term severe LEEs (P = 0.05). Eight (10%) of 84 patients showed grade 2 LEEs for at least 30% of the follow-up. Advanced liver fibrosis was observed in 28 (37%) of 76 subjects who did not develop long-term grade 2 LEEs and in three (38%) of eight patients who developed them (P = 0.9). CONCLUSIONS: In HIV/HCV-coinfected patients, non-severe LEEs, whether persistent or not, are not associated with advanced liver fibrosis. On the other hand, long-term severe LEEs are associated with more severe liver fibrosis in this population.  相似文献   
149.
150.
Although there is increasing evidence that blood‐derived macrophages support tumor progression, it is still unclear whether specialized resident macrophages, such as brain microglia, also play a prominent role in metastasis formation. Here, we show that microglia enhance invasion and colonization of brain tissue by breast cancer cells, serving both as active transporters and guiding rails. This is antagonized by inactivation of microglia as well as by the Wnt inhibitor Dickkopf‐2. Proinvasive microglia demonstrate altered morphology, but neither upregulation of M2‐like cytokines nor differential gene expression. Bacterial lipopolysacharide shifts tumor‐educated microglia into a classical M1 phenotype, reduces their proinvasive function, and unmasks inflammatory and Wnt signaling as the most strongly regulated pathways. Histological findings in human brain metastases underline the significance of these results. In conclusion, microglia are critical for the successful colonization of the brain by epithelial cancer cells, suggesting inhibition of proinvasive microglia as a promising antimetastatic strategy. © 2010 Wiley‐Liss, Inc.  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