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   14153篇
  免费   891篇
  国内免费   46篇
耳鼻咽喉   161篇
儿科学   757篇
妇产科学   308篇
基础医学   1600篇
口腔科学   415篇
临床医学   971篇
内科学   3096篇
皮肤病学   270篇
神经病学   788篇
特种医学   575篇
外国民族医学   1篇
外科学   2137篇
综合类   412篇
一般理论   11篇
预防医学   829篇
眼科学   425篇
药学   1387篇
中国医学   89篇
肿瘤学   858篇
  2023年   103篇
  2022年   76篇
  2021年   417篇
  2020年   293篇
  2019年   343篇
  2018年   441篇
  2017年   323篇
  2016年   361篇
  2015年   395篇
  2014年   562篇
  2013年   727篇
  2012年   1016篇
  2011年   1091篇
  2010年   643篇
  2009年   505篇
  2008年   824篇
  2007年   812篇
  2006年   718篇
  2005年   638篇
  2004年   606篇
  2003年   484篇
  2002年   472篇
  2001年   270篇
  2000年   271篇
  1999年   237篇
  1998年   119篇
  1997年   72篇
  1996年   60篇
  1995年   85篇
  1994年   67篇
  1993年   65篇
  1992年   135篇
  1991年   142篇
  1990年   123篇
  1989年   138篇
  1988年   115篇
  1987年   109篇
  1986年   87篇
  1985年   86篇
  1984年   100篇
  1983年   80篇
  1982年   58篇
  1980年   50篇
  1979年   74篇
  1977年   43篇
  1976年   49篇
  1974年   49篇
  1973年   59篇
  1972年   43篇
  1969年   43篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
The mechanisms linking tumor microenvironment acidosis to disease progression are not understood. Here, we used mammary, pancreatic, and colon cancer cells to show that adaptation to growth at an extracellular pH (pHe) mimicking acidic tumor niches is associated with upregulated net acid extrusion capacity and elevated intracellular pH at physiological pHe, but not at acidic pHe. Using metabolic profiling, shotgun lipidomics, imaging and biochemical analyses, we show that the acid adaptation-induced phenotype is characterized by a shift toward oxidative metabolism, increased lipid droplet-, triacylglycerol-, peroxisome content and mitochondrial hyperfusion. Peroxisome proliferator-activated receptor-α (PPARA, PPARα) expression and activity are upregulated, at least in part by increased fatty acid uptake. PPARα upregulates genes driving increased mitochondrial and peroxisomal mass and β-oxidation capacity, including mitochondrial lipid import proteins CPT1A, CPT2 and SLC25A20, electron transport chain components, peroxisomal proteins PEX11A and ACOX1, and thioredoxin-interacting protein (TXNIP), a negative regulator of glycolysis. This endows acid-adapted cancer cells with increased capacity for utilizing fatty acids for metabolic needs, while limiting glycolysis. As a consequence, the acid-adapted cells exhibit increased sensitivity to PPARα inhibition. We conclude that PPARα is a key upstream regulator of metabolic changes favoring cancer cell survival in acidic tumor niches.  相似文献   
2.
3.

Background

Multiple myeloma (MM) is a hematologic malignancy of plasma cell origin. MM primarily affects bone marrow, but extramedullary sites can also be involved. Myelomatous pleural effusion (MPE) is an atypical and rare complication of MM. We aimed to systematically study the incidence and clinicopathologic profile of patients with MPE in a real-world setting.

Patients and Methods

In this retrospective study, 415 consecutive patients with MM managed at a tertiary care center in North India during a study period of January 1, 2010 to December 31, 2015 were evaluated for MPE. The patients with MPE were analyzed for their clinical profile, diagnosis, treatment, and outcomes.

Results

Of these 415 patients, 11 (2.65%) patients had MPE. The median age of the study population was 50 years with male preponderance. The majority of these patients had immunoglobin (Ig)G Kappa disease. All patients had higher than International Staging System stage I disease. MPE was a presenting feature at MM diagnosis in 45.45% (n = 5) of the patients, whereas the rest developed MPE during follow-up. MPE presented predominantly (81.8%) as a unilateral effusion. Concurrent extramedullary involvement at other site was seen in 45.45% (n = 5), with 3 (27%) patients having concurrent myelomatous ascites. Six of these were managed aggressively, whereas 5 patients opted for palliation. The outcomes were dismal (90.9% mortality), with a median survival of 2.47 months.

Conclusion

MPE is a rare entity, and positive outcomes of therapy remain low with dismal prognosis.  相似文献   
4.
Myung Sun Kim MD  Vinay Prasad MD  MPH 《Cancer》2020,126(19):4270-4272
The US Food and Drug Administration granted acalabrutinib approval as the second Bruton tyrosine kinase (BTK) inhibitor to treat patients with chronic lymphocytic leukemia and small lymphocytic lymphoma as monotherapy or in combination with obinutuzumab. This approval was based on 2 phase 3 trials: ELEVATE-TN and ASCEND. There are several concerns with the design of these trials, including suboptimal treatment of patients in the control arm, expansion of the trial population, and lack of data regarding efficacy or tolerability compared with ibrutinib, a first-in-class drug. The Food and Drug Administration approval of acalabrutinib for patients with chronic lymphocytic leukemia and small lymphocytic lymphoma represents concerning drug approval patterns in the United States and a weakness in evidence generation.  相似文献   
5.
6.
Clinical Oral Investigations - This study compared the effects of oral hygiene with a toothpaste formulated with zinc (test) to a fluoride dentifrice (control) for effects on oral polymorphonuclear...  相似文献   
7.
8.
9.
Background and aimsMenopause is a physiological process in nature and hence, variations in the age of menopause are not expected. Hence, the study was conducted with an objective to calculate the reliable estimates of age at menopause for India, and understand the differentials in women’s age at menopause throughout the country.MethodsA total of 202 studies of age at menopause, covering the period 2009–2020, were accessed from PubMed database and Google. Of these only ten studies met the selection criteria for this paper, which is that the data for these studies must be collected from house-to-house surveys.ResultsThe average age at menopause in India, with minimal publication bias, is 46.6 years (95% CI: 44.83, 48.44). In one study slightly above 1.96 Standard Deviation, was observed, as ascertained by Funnel Plot and Egger’s test. The mean age ranged from a minimum of 44.69 years (95% CI: 35.01, 54.37) to a maximum of 48.95 (95% CI: 42.29, 55.61) years. Furthermore, the age at menopause did not exhibit any significant variation by age at menarche, although the association was positive.ConclusionsThe age at menopause showed positive association with age at menarche. In India, during the period 2009–2020, it was 46.6 years, which significantly lower than the age in some developed countries. The differences may be methodological since no information was found regarding the distribution of age at menopause in the studies that were considered for meta-analysis.  相似文献   
10.
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