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   9669篇
  免费   394篇
  国内免费   49篇
耳鼻咽喉   98篇
儿科学   152篇
妇产科学   75篇
基础医学   1087篇
口腔科学   318篇
临床医学   614篇
内科学   2479篇
皮肤病学   267篇
神经病学   634篇
特种医学   345篇
外科学   1594篇
综合类   24篇
预防医学   333篇
眼科学   161篇
药学   896篇
  1篇
中国医学   10篇
肿瘤学   1024篇
  2024年   39篇
  2023年   114篇
  2022年   194篇
  2021年   341篇
  2020年   180篇
  2019年   223篇
  2018年   277篇
  2017年   183篇
  2016年   211篇
  2015年   176篇
  2014年   248篇
  2013年   329篇
  2012年   446篇
  2011年   476篇
  2010年   281篇
  2009年   212篇
  2008年   409篇
  2007年   435篇
  2006年   423篇
  2005年   434篇
  2004年   377篇
  2003年   385篇
  2002年   374篇
  2001年   288篇
  2000年   331篇
  1999年   283篇
  1998年   82篇
  1997年   78篇
  1996年   73篇
  1995年   62篇
  1994年   52篇
  1993年   52篇
  1992年   187篇
  1991年   158篇
  1990年   163篇
  1989年   165篇
  1988年   152篇
  1987年   144篇
  1986年   129篇
  1985年   124篇
  1984年   99篇
  1983年   76篇
  1979年   57篇
  1978年   44篇
  1977年   45篇
  1973年   50篇
  1972年   41篇
  1971年   42篇
  1969年   49篇
  1968年   51篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
BACKGROUND: Bronchoalveolar lavage (BAL) is an established technique for measuring antibiotic concentrations in the epithelial lining fluid (ELF) of the bronchiolar and alveolar regions; however, the results may not reflect concentrations in bronchial regions. Bronchoscopic microsampling (BMS) is a technique that makes it possible to obtain multiple samples from bronchial ELF. OBJECTIVE: BMS and BAL were used to analyze the pharmacokinetics of gatifloxacin in bronchial ELF from healthy young adult subjects and adult patients with chronic bronchitis. METHODS: Bronchial ELF samples were obtained by BMS at 1, 2, 3, 4, 6, 10, and 24 hours after administration of a single oral dose of gatifloxacin 200 mg in healthy young adult (aged 20-25 years) subjects, and at 1, 2, 4, and 10 hours after a single dose in patients with chronic bronchitis (aged > or =20 years). At least 1 month after the initial BMS, alveolar (BAL) and bronchial (BMS) ELF samples were obtained from another group of healthy subjects 2 hours after administration of a single oral dose of gatifloxacin 200 mg for comparison of gatifloxacin concentrations in samples obtained by the 2 techniques. RESULTS: Bronchial ELF samples were obtained from 8 healthy subjects and 5 patients with chronic bronchitis; alveolar ELF samples were obtained from a separate group of 5 healthy subjects. For the healthy subjects, the mean (SD) AUC(0-24) in serum and bronchial ELF, corrected for mg/kg doses, was 4.6 (1.1) and 7.6 (3.5) mg x h/L, respectively. In the patients with chronic bronchitis, the AUC(0-10) in serum and bronchial ELF, corrected for mg/kg doses, was 3.9 (0.8) and 4.1 (1.5) mg x h/L. The C(max) in serum and bronchial ELF, corrected for mg/kg doses, was 0.6 (0.2) and 1.4 (0.8) mg/L in healthy subjects and 0.7 (0.2) and 0.7 (0.2) mg/L in patients with chronic bronchitis. In healthy subjects, the C(max) and AUC(0-24) were significantly higher in bronchial ELF than in serum (both, P < 0.05). Gatifloxacin concentrations were significantly lower in bronchial ELF obtained by BMS than in alveolar ELF obtained by BAL (P < 0.05). CONCLUSIONS: Based on the findings of this study in small numbers of healthy young adult volunteers and patients with chronic bronchitis, BMS appears to be a promising method for measuring drug concentrations and determining the pharmacokinetic profile of gatifloxacin in bronchial ELF. Additional studies are needed to correlate measured concentrations obtained by BMS with clinical and/or microbiologic outcomes in larger populations.  相似文献   
52.
To investigate the mechanisms of action underlying the anti-inflammatory effects of the nonsteroidal anti-inflammatory drug aceclofenac in humans, we studied the metabolism of aceclofenac in detail in primary cultured synovial cells of 10 patients with rheumatoid arthritis. Aceclofenac and 4'-hydroxyaceclofenac are the major compounds in human blood after the administration of aceclofenac, but they had no inhibitory effects on cyclooxygenase (COX) activity or COX expression in the rheumatoid synovial cells. In contrast, aceclofenac and 4'-hydroxyaceclofenac reduced prostaglandin E2 (PGE2) production by the rheumatoid synovial cells. We also observed that aceclofenac and 4'-hydroxyaceclofenac were hydrolyzed into the COX inhibitors diclofenac and 4'-hydroxydiclofenac, respectively, by the rheumatoid synovial cells. However, the hydrolytic activity differed markedly among the cell preparations. Because the suppressive potency of aceclofenac and 4'-hydroxyaceclofenac against the PGE2 production was proportionally correlated with the hydrolytic activity in rheumatoid synovial cell preparations, we suggest that the suppressive effects of aceclofenac and 4'-hydroxy aceclofenac on PGE2 production are facilitated by the hydrolytic activity in rheumatoid synovial cells.  相似文献   
53.
Here we report what is to our knowledge the first identified Japanese family afflicted by X-linked myopathy with excessive autophagy. The index case is a 52-year-old man with almost 40 years of progressive proximal muscle weakness. High urinary β2 microglobulin, normal serum β2 microglobulin, autophagic vacuoles with sarcolemmal features, and a hemizygous c.164–7T>G mutation in the VMA21 gene were found. His two maternal uncles had similar clinicopathological findings. High urinary β2 microglobulin without obvious renal dysfunction might result from decreased urine acidification in the distal convoluted tubules caused by the VMA21 gene mutation. These findings might prove to be useful as a preliminary marker suggestive of X-linked myopathy with excessive autophagy.  相似文献   
54.
55.
56.
BackgroundSmall cell carcinoma of the urinary bladder (SCUB) is rare. The optimal treatment for SCUB remains unclear. To address the problem of appropriate treatment for each case, we assessed single-modality and surgery-based multimodality treatments in patients with SCUB.Materials and methodsWe retrospectively reviewed the medical records of 12 patients with SCUB between 1990 and 2013. All patients underwent transurethral resection of the bladder tumor and were diagnosed with SCUB. Their clinicopathological characteristics were assessed, and the outcomes were compared according to the treatment modality.ResultsThe median (range) age at diagnosis was 66 years (range, 53–85 years). T1–4N0M0 was observed in 8 patients (66%), N1–3M0 in 2 (17%), and NanyM1 in 2 (17%). After transurethral resection of the bladder tumor, 6 patients (50%) underwent cystectomy alone, and 4 (33%) underwent cystectomy and presurgical or adjuvant chemotherapy with etoposide and cisplatin. During the median follow-up period of 20.7 months, 6 patients (50%) died of cancer, and 2 patients (17%) died of other causes. The median overall survival period was 1.9 years. The 5-year overall survival rate in patients who underwent cystectomy and chemotherapy was 75%, whereas that in those who underwent cystectomy alone and transurethral resection alone were 22% and 0%, respectively (p = 0.012). Recurrence-free survival was significantly correlated with cause-specific survival (r = 0.95; 95% confidence interval, 0.81–0.99; p < 0.001).ConclusionsRadical cystectomy with chemotherapy using the etoposide and cisplatin regimen improved the prognosis of patients with SCUB and TxNxM0. The time from initial progression to death due to cancer was very short, indicating that the initial treatment strategy is crucial.  相似文献   
57.
58.
Inflammatory and immune cells in the tumor microenvironment are reported to be associated with tumor progression in several cancers. In total, 225 patients who underwent initial and curative hepatectomy for hepatocellular carcinoma (HCC) from 2004 to 2013 were enrolled in this study. Tumor‐associated neutrophils (TANs), M2 macrophages (TAMs; tumor‐associated macrophages), CD8+ T cells, and regulatory T cells (Tregs) were evaluated by immunohistochemistry (IHC), and their relationships with patient clinicopathological characteristics and prognosis were evaluated. IHC was performed focusing on TANs first. We could not find a relationship between intratumoral and peritumoral TANs and clinicopathological features except for the fibrous capsule and infiltration of tumors into capsule. Next, TAMs, CD8+ cells and Tregs were evaluated by IHC. At the peritumoral area, TANs and TAMs (r = 0.36, p = 0.001) or Tregs (r = 0.16, p = 0.008) showed a positive correlation, whereas TANs and CD8+ cells showed a negative correlation (r = −0.16, p = 0.02). As for survival outcomes, at the peritumoral area, high TANs (p = 0.0398), low CD8+ cells (p = 0.0275), and high TAMs (p = 0.001) were significantly associated with worse overall survival (OS). In addition, high TANs (p = 0.010), and high TAMs (p = 0.00125) were significantly associated with worse disease‐free survival (DFS). Finally, we established a risk signature model by combining the expression patterns of these cells. The high‐risk signature group had significantly worse OS (p = 0.0277) and DFS (p = 0.0219) compared with those in the low‐risk signature group. Our risk signature based on immune cells at the peritumoral area of the HCC can predict patient prognosis of HCC after curative hepatectomy.  相似文献   
59.
A 71-year-old man complained of nausea and loss of appetite for eight months prior to admission. He was transported to a hospital with disorientation and diagnosed with primary hyperparathyroidism by laboratory examinations. However, ultrasonography, computed tomography, and technetium-99m labeled methoxyisobutyl isonitrile (99mTc-MIBI) with single-photon emission computed tomography did not yield definite results. In contrast, somatostatin receptor scintigraphy successfully identified the lesion responsible for the over-secretion of parathyroid hormone within the middle mediastinum. The tumor was successfully resected by surgery, and a histopathological analysis confirmed the parathyroid adenoma nature of the tumor.  相似文献   
60.
A 94-year-old man was diagnosed with immunoglobulin A vasculitis (IgAV), and losartan was initiated. His renal function rapidly deteriorated over a month; therefore, methylprednisolone was administered intravenously for three days followed by oral prednisolone. Renal function improvement and both proteinuria and hematuria remission were observed within six months. Prednisolone tapering was completed at eight months. In this case, we monitored the patient carefully and started glucocorticoids as soon as the patient''s renal function deteriorated. We were thus able to treat the patient with a relatively small dose of glucocorticoids in a short treatment period without any adverse events due to glucocorticoids.  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