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   1509篇
  免费   57篇
  国内免费   5篇
耳鼻咽喉   16篇
儿科学   31篇
妇产科学   26篇
基础医学   235篇
口腔科学   60篇
临床医学   63篇
内科学   290篇
皮肤病学   15篇
神经病学   111篇
特种医学   62篇
外科学   287篇
综合类   1篇
预防医学   22篇
眼科学   3篇
药学   158篇
中国医学   4篇
肿瘤学   187篇
  2023年   4篇
  2022年   12篇
  2021年   28篇
  2020年   12篇
  2019年   11篇
  2018年   22篇
  2017年   15篇
  2016年   11篇
  2015年   14篇
  2014年   27篇
  2013年   28篇
  2012年   48篇
  2011年   65篇
  2010年   30篇
  2009年   39篇
  2008年   52篇
  2007年   71篇
  2006年   85篇
  2005年   101篇
  2004年   84篇
  2003年   78篇
  2002年   83篇
  2001年   56篇
  2000年   64篇
  1999年   56篇
  1998年   31篇
  1997年   20篇
  1996年   21篇
  1995年   23篇
  1994年   23篇
  1993年   27篇
  1992年   49篇
  1991年   52篇
  1990年   39篇
  1989年   40篇
  1988年   43篇
  1987年   28篇
  1986年   22篇
  1985年   16篇
  1984年   6篇
  1983年   10篇
  1982年   3篇
  1981年   6篇
  1980年   2篇
  1979年   4篇
  1976年   2篇
  1973年   1篇
  1968年   1篇
  1925年   1篇
  1922年   2篇
排序方式: 共有1571条查询结果,搜索用时 10 毫秒
101.
102.
Samples of blood or other animal fluids contain a variety of substances that inhibit the polymerase chain reaction (PCR), meaning that isolation of DNA, involving multiple labor-intensive steps, is generally necessary prior to PCR. We have developed a novel reagent cocktail that effectively suppresses these inhibitory substances. Using this reagent cocktail, DNA from various targets can be efficiently amplified directly from various forms of blood samples without DNA isolation. 1. DNA sequences within the beta-globin gene could be amplified directly from human blood samples treated with various anticoagulants. Either fresh blood or blood samples stored frozen for up to 4 years could be used for PCR. 2. DNA sequences of up to 2056 bp within the beta-globin gene could be amplified directly from human blood samples. 3. Human chromosomal and mitochondrial DNA from different individuals could be amplified directly from blood samples. 4. Low titers of hepatitis B virus could be amplified directly from human blood samples. 5. DNA could be amplified directly from various target sequences using dried blood in a PCR tube or on a filter paper. 6. Transgenes could be detected directly in blood samples from transgenic mice.  相似文献   
103.
Taxol is an effective anti-tumour drug against a variety of tumour cells. Taxol directly induces apoptosis in addition to a G2/M cell cycle arrest. However, it remains poorly understood how Taxol induces apoptosis in tumour cells. Taxol induces the secretion of inflammatory cytokines in murine macrophages in a toll-like receptor-4 (TLR-4)-dependent manner in addition to its anti-tumour effects, but the effect of Taxol on human macrophages is controversial. In this study, we demonstrated that low doses (less than 1000 nmol/l) of Taxol induced the expression of tumour necrosis factor (TNF)-alpha in human myelomonocytic cells and that the induction of TNF-alpha mRNA was inhibited by dominant-negative myeloid differentiation protein (dnMyD88). Furthermore, we demonstrated that the same doses of Taxol induced apoptosis of the same myelomonocytic cells and that the Taxol-induced apoptosis was also inhibited by dnMyD88. In accordance with the previous reports, Taxol induced the expression of TNF-alpha and apoptosis in a TLR4-independent manner. These results suggest that TNF-alpha expression and apoptosis, both induced by Taxol in human myelomonocytic cells, share the signal transduction molecule MyD88.  相似文献   
104.
A 77-year-old man suffered subarachnoid hemorrhage due to a ruptured aneurysm of the distal anterior inferior cerebellar artery (AICA). He had a history of hearing disturbance in the left ear for more than 3 years. Computed tomography on three separate occasions had found no abnormalities. One month before the hemorrhage, he came to our outpatient service complaining of vertigo. Magnetic resonance (MR) imaging and MR angiography detected no abnormality. Conventional angiography demonstrated an aneurysm of 8 mm diameter in the distal AICA region after the hemorrhage. Filling and wash out of the aneurysm sac by contrast medium was markedly delayed, which suggested that MR imaging had failed to detect the flow void because of the slow blood flow in the dome. The aneurysm was clipped successfully. He was discharged with mild dysarthria on the 33rd postoperative day. MR angiography has limitations in detecting unruptured aneurysms and there is certainly a high risk group of false negatives, including aneurysms located in the distal region of the main trunk.  相似文献   
105.
We treated five cases for multiple hepatic metastases from gastric cancer with a novel combination of TS-1 and low-dose cisplatinum (CDDP). TS-1 was orally administered at 100 mg/body/day every day or only on weekdays, and 10 mg of CDDP was infused once or twice a week. The efficacy was evaluated by body CT after the treatment. The CT showed more than a 60% reduction of hepatic tumors in four patients. The tumor markers, CEA and CA19-9, were reduced to 10%. The response rate was 80%. Adverse reactions of grade 1 anemia were observed in two patients and grade 1 leucopenia in one patient. The liver function normalized in one patient. The hemoglobin level was increased from 6.8 g/dl to 11.8 g/dl in one patient. In conclusion, this combined chemotherapy of TS-1 and low-dose CDDP proved useful for advanced gastric cancer patients with multiple hepatic metastases, in view of its therapeutic efficacy, patients' quality of life and low toxicity.  相似文献   
106.
We have reported that ONO-4007, a novel synthetic lipid A derivative with low toxic activities, produced large amount of tumor necrosis factor (TNF)-alpha selectively in the tumor tissues and brought about complete cures in about 60% of rats bearing TNF-alpha sensitive KDH-8 cells, which also secreted a large amount of transforming growth factor (TGF)-beta. In our present study, to explore ONO-4007 induced Th1-type immune response, we investigated the mRNA expression of interferon (IFN)-gamma, Interleukin (IL)-1beta, IL-6, IL-10, IL-12 in KDH-8 bearing rats. We next examined the nitric oxide (NO) production. We found that IFN-gamma, IL-1beta, IL-6 and IL-12 mRNA expression of the tumor tissue were higher in the ONO-4007 treated rats than in phosphate buffer saline (PBS) treated rats. Western blotting also revealed that IL-12 protein production was increased. NO production from peritoneal macrophages were suppressed in tumor-bearing rats, but ONO-4007 restored it up to the normal level. These results suggest that ONO-4007 induces and restores Th1-type immune response through cytokine production cascade, followed by initial TNF-alpha production, eventually leading to tumor eradication.  相似文献   
107.
OBJECTIVE: To longitudinally evaluate disturbances of the hypothalamic-pituitary-adrenal (HPA) axis in women with secondary progestin-negative hypothalamic amenorrhea. DESIGN: Retrospective cohort study. SETTING: Yokohama City University, Yokohama, Japan. PATIENT(S): Twenty-four women with progestin-negative hypothalamic amenorrhea. INTERVENTION(S): Administration of human corticotropin-releasing hormone (hCRH) and treatment with a combination of estrogen and progesterone. MAIN OUTCOME MEASURE(S): Plasma cortisol and ACTH concentrations and period required for recovery from amenorrhea. RESULT(S): Plasma ACTH concentrations 30 and 60 minutes after injection of hCRH and the percent maximum increment (%Cmax) of ACTH were significantly lower in the amenorrheic patients compared with the control group patients. The basal cortisol was significantly higher, and the %Cmax of cortisol was significantly lower. In the 16 patients who recovered from amenorrhea, there was a significant positive correlation (Y = 1.93X-10.8, r = 0.629) between the basal cortisol concentrations (X) and the period for recovery (Y). The serum E2 gradually increased before recovery, and this E2 increase was preceded by changes in the plasma cortisol concentration and the %Cmax values of cortisol and ACTH. CONCLUSION(S): The CRH test might be useful for evaluating the roles of stress and for estimating the period required for recovery in hypothalamic amenorrhea.  相似文献   
108.
BACKGROUND: The survival rate of patients with advanced-stage mucinous cystadenocarcinoma of the ovary is dismal and no best treatment is known. We report a case of complete response of a stage IV mucinous cystadenocarcinoma of the ovary to systemic chemotherapy employing paclitaxel and carboplatin. CASE: A 51-year-old nullipara diagnosed with International Federation of Gynecology and Obstetrics stage IV mucinous cystadenocarcinoma of the ovary underwent cytoreductive surgery followed by systemic chemotherapy employing paclitaxel and carboplatin every 4 weeks for 3 courses. The patient tolerated chemotherapy well, demonstrated a remarkable response showing no evidence of malignancy at a second-look laparotomy. As a consolidation chemotherapy after negative second-look laparotomy, she underwent another three courses of chemotherapy of the same regimen, and is showing no evidence of disease. CONCLUSION: Paclitaxel and carboplatin may be effective in treating mucinous cystadenocarcinoma of the ovary.  相似文献   
109.
110.
Tumors arising from the liver, biliary tract and pancreas, which originate in the foregut and are in close anatomical proximity to each other, sometimes show similar histological features. No studies have focused on genetic similarities and differences between tumors of these organs. To elucidate the similarities and differences in DNA copy number alterations between tumors of these organs, we applied comparative genomic hybridization (CGH) to cancers of the liver (31 cases), biliary tract (42 cases) and pancreas (27 cases). Some alterations were common to tumors of all three organs, and some were preferential in certain types of tumor. Gains of 1q and 8q and losses of 8p and 17p were common to all tumors. In contrast, 13q14 and 16q losses were detected exclusively in hepatocellular carcinomas (HCCs; p < 0.01). The incidence of 17q21 gain and 5q loss was higher in biliary tract cancers than in the other two types (p < 0.05). Pancreatic cancers exhibited higher incidence of 5q14-q23 gain and 19p loss than tumors of other organs (p < 0.01). Gains of 7p, 7q, 12p and 20q and losses of 3p, 6q, 9p and 18q were frequent in both biliary tract and pancreatic cancers but rare in HCCs (p < 0.05). The present results suggest that although genes located at 1q, 8p, 8q and 17p are frequently involved in HCC, biliary tract and pancreatic cancer, at least some of the genes implicated in carcinogenesis are different between these three types. It is also suggested that CGH analysis is useful as a potential adjunct for the diagnosis and management of these tumors of organs that are anatomically close to one another.  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