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   561篇
  免费   10篇
  国内免费   3篇
耳鼻咽喉   16篇
儿科学   36篇
妇产科学   76篇
基础医学   38篇
口腔科学   31篇
临床医学   45篇
内科学   79篇
皮肤病学   5篇
神经病学   42篇
特种医学   14篇
外科学   103篇
综合类   8篇
预防医学   10篇
眼科学   23篇
药学   31篇
肿瘤学   17篇
  2023年   3篇
  2022年   4篇
  2021年   3篇
  2020年   5篇
  2019年   8篇
  2018年   3篇
  2017年   5篇
  2016年   11篇
  2015年   14篇
  2014年   14篇
  2013年   22篇
  2012年   43篇
  2011年   30篇
  2010年   25篇
  2009年   27篇
  2008年   33篇
  2007年   45篇
  2006年   43篇
  2005年   34篇
  2004年   44篇
  2003年   50篇
  2002年   45篇
  2001年   12篇
  2000年   10篇
  1999年   8篇
  1998年   3篇
  1997年   1篇
  1996年   1篇
  1995年   4篇
  1994年   1篇
  1993年   2篇
  1992年   3篇
  1991年   2篇
  1990年   2篇
  1989年   2篇
  1988年   1篇
  1987年   1篇
  1978年   1篇
  1977年   2篇
  1975年   1篇
  1974年   2篇
  1972年   1篇
  1971年   1篇
  1964年   1篇
  1960年   1篇
排序方式: 共有574条查询结果,搜索用时 156 毫秒
21.
Here, we describe the characteristics of a Pt‐blue complex [Pt4(2‐atp)8(H2O)(OH)] (2‐atp: 2‐aminothiophenol) as a prodrug for its DNA‐binding properties and its use in cancer therapy. The nature of the interaction between the Pt‐blue complex and DNA was evaluated based on spectroscopic measurements, the electronic absorption spectra, thermal behavior, viscosity, fluorometric titration, and agarose gel electrophoresis. Our results suggested that the compound was able to partially intercalate DNA and appeared to induce both single‐ and double‐stranded breaks (DBS) on DNA in vitro, but no DSBs in cells. The ability of the compound to induce DNA damage was dependent on reactive oxygen species (ROS) in vitro. There was also elevated formation of ROS and SOD expression in response to drug treatment in cell culture. The complex was found to be more cytotoxic to cancer cells in comparison with noncancer controls using WST‐1 assay. The mean of cell death was determined to be apoptosis as assessed via biochemical, morphological, and molecular observations, including DNA condensation/fragmentation analysis, live cell imaging microscopy, TUNEL analyses, and increase in the levels of pro‐apoptotic genes such as Bag3, Bak, Bik, Bmf, and Hrk. Hence, the Pt‐blue complex under study grants premise for further studies.  相似文献   
22.
23.
24.
Context: Excess use of alcohol is known to be associated with liver diseases such as fatty liver, alcoholic hepatitis, and cirrhosis. Various practices may be applied to prevent or treat the damage caused by chronic alcoholism. Coprinus comatus (O.F. Müll.) Pers. (Agaricaceae) is a macrofungus that has been reported to aid the recovery of murine livers damaged by benzopyrene.

Objective: In this study, the possible therapeutic effects of three different doses (50, 100, and 150?mg/kg) of C. comatus polysaccharide (PS) extract were studied in rats subjected to an alcoholic diet. The histological and biochemical results were compared between the control and experimental groups.

Materials and methods: Modified Lieber–Decarli’s calorie-adjusted liquid alcohol diet was given orally for 60?d. In addition to histopathology, alanine transaminase (ALT), aspartate transaminase (AST), mitochondrial membrane integrity, total cytochrome-c oxidase activity (TotalStCox), total mitochondrial cytochrome-c oxidase activity (TotalMtStCox), and caspase-3 values were used as liver parameters, and liver sections from all experimental groups were examined by electron microscopy.

Results: Using histopathological assessment, it was observed that there was a decline in liver hepatocyte vacuolization in the treatment group fed 50?mg PS/kg. The TotalStCox and TotalMtStCox values of this group differed from the EtOH control group (p?Discussion and conclusion: Daily administration of 50?mg/kg of C. comatus PS extract considerably reduced the negative effects of alcohol on liver structure and function.  相似文献   
25.
A number of 3-(4-substituted benzoylmethyl)-2-benzoxazolinones have been synthesized by reacting with 2-benzoxazolinone and 4-substituted phenacyl bromide in ethanol. Their chemical structures were confirmed by IR, 1H NMR and elemental analysis. For screening antimicrobial activity, minimum inhibitory concentration (MIC) values were determined against two Gram positive, one Gram negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus) and three yeast-like the fungi (Candida albicans, Candida krusei, Candida parapsilosis).  相似文献   
26.
The objective of this study was to retrospectively investigate a single institution's experience with carotid artery resection performed as part of an oncological procedure and to determine acute and convalescent complication and survival rates. We performed a record review of 28 patients with head and neck malignancy invading the carotid artery. Immediate carotid artery resection and ligation on an emergent basis was performed on 12 patients (group 1), elective resection and ligation was performed on 8 patients (group 2), and elective resection and revascularization was performed on 8 patients (group 3). In group 1, although 1 patient survived for 1 year and 1 patient survived for 2 years, 1 patient died of severe neurologic deficit, 2 patients experienced neurologic deficit with good recovery, and 1 patient was moderately disabled. In group 2, 2 patients survived without disease for 5 years, and 2 patients experienced neurologic deficit, 1 with good recovery and the other with complete recovery. In group 3, only 1 patient survived for 5 years, and within this group, 1 patient died of severe neurologic deficit, 1 patient had neurologic deficit with moderate recovery, and 1 patient had neurologic deficit with complete recovery. No significant difference in mortality and morbidity rate was observed between the "resection and ligation" group and the "resection and revascularization" group (p = .52, chi(2) = 0.79). We conclude that the surgical treatment of patients with an invaded carotid artery, including carotid resection, provides a small but real chance of 5-year survival. The methods of carotid resection and repair should be guided by clinical presentation and by preoperative and intraoperative investigations.  相似文献   
27.
PURPOSE: The aim of the study was to examine the effect of articaine hydrochloride (AH) on the healing of surgical wounds and to compare healing with that of lidocaine. MATERIALS AND METHODS: Forty rats were used in this study. The rats were randomly separated into 4 groups. Three groups were given 2% lidocaine, 4% AH, or injectable saline, and the fourth was a control group. Skin specimens underwent the breaking strength test (BST) and histologic examination at 1 week after the surgical procedure. The skin specimens of the rats were subjected to a pulling force of 10 mm/min across the incision line. The strength value at the moment of breaking in the tissue was expressed in Newtons. Histologic examination was performed as well, and wound healing was graded. RESULTS: Both the histologic grade and BST values in the lidocaine and AH groups were significantly lower than those of the control and saline groups (P <.01). Similarly, the histologic and BST values of the AH and lidocaine groups were statistically significant (P <.05, P <.001). Some necrotic regions were observed at the incision region in 2 samples from the AH group. CONCLUSION: The results of the study showed that AH is as safe a local anesthetic agent as lidocaine from the standpoint of wound response.  相似文献   
28.
We assessed the relationship between tonsillectomy and being a habitual or severe snorer. Volunteers were asked to provide their age and sex, a detailed snoring history covering the frequency and intensity of snoring, and their smoking and alcohol intake habits. After oral and nasal examinations, the tonsil size scores, Mallampati index scores, and nasal obstructions of the volunteers were recorded. Body heights and weights were measured, and body mass indexes were calculated. Being male, aging, an increase in body mass index and tonsillectomy were identified as independent risk factors for being a habitual and severe snorer. Although a nasal obstruction was found to be an independent risk factor for being a habitual snorer, an obstructive tongue base was identified as an independent risk factor for being a severe snorer. Tonsillectomy reduces the risk of being both a habitual and severe snorer. This reduced incidence and intensity of snoring following tonsillectomy could be accepted as a long-term beneficial side effect of the operation.  相似文献   
29.
Tetrahydrobiopterin (BH4) deficiencies are a heterogeneous group of disorders caused by a defect in two of the three enzymes involved in its biosynthesis or in the two recycling enzymes. Except for the deficiency of dehydratase, an enzyme catalyzing a reaction in the recycling pathway, all other variants of BH4 deficiency are characterized by developmental delay, progressive neurological deterioration, hypokinesis, drooling, swallowing difficulty, truncal hypotonia, increased limb tone, myoclonus and brisk deep tendon reflexes. A deficiency of guanosine triphosphate cyclohydrolase I (GTPCH), the first enzyme in the biosynthetic pathway of BH4, is described in a 14-month-old male infant with hyperphenylalaninemia, developmental delay, hypertonia of the extremities, seizures, feeding difficulties, and vomiting. Urinary pteridine screening revealed very low levels of neopterin and biopterin which was highly suggestive of GTPCH deficiency. Low cerebrospinal fluid concentrations of 5-hydroxyindoleacetic acid (5HIAA) and homovanillic acid concentrations, together with no detectable neopterin and decreased concentrations of biopterin and folate, agreed with the diagnosis of GTPCH deficiency. Subsequently measured neopterin and biopterin synthesis in cytokine-stimulated skin fibroblasts confirmed GTPCH deficiency, albeit indirectly. The patient showed marked improvement on a low-protein low-phenylalanine diet with neurotransmitter precursor administration. The favorable outcome in this patient clearly shows that not only newborns with elevated phenylalanine levels but also older children with neurological signs and symptoms should be screened for a BH4 deficiency in order to have maximum benefit of the treatment.  相似文献   
30.
BACKGROUND: To investigate the diagnostic efficacy of preoperative lymphoscintigraphy (LS), Ga-67 scintigraphy (GS) and computed tomography (CT) for detection of lymph node metastasis in patients with endometrial or ovarian carcinoma. METHODS: The results of preoperative LS, GS and CT used to detect lymph node metastasis were compared to the postoperative histopathological results of lymph node dissection materials of a total of 37 patients, including 16 patients with endometrial and 21 patients with ovarian carcinomas. The diagnostic efficacy of these methods for detecting lymph node metastasis were calculated. RESULTS: When the results of all of the patients were taken into account, the preoperative LS, GS and CT were found to have sensitivities of 50%, 20% and 40% and specificities of 51.8%, 96.3%, and 92.6%, respectively, for detection of pelvic lymph node metastasis. The same methods had sensitivities of 27.3%, 27.3% and 72.7% and specificities of 88.5%, 88.5%, 84.6%, respectively, for detecting para-aortic lymph node metastasis in all patients. CONCLUSION: These data suggested that although LS, GS and CT had relatively high specificity, low sensitivity of these imaging methods precluded their routine preoperative use for diagnosis of lymph node metastasis of ovarian or endometrial carcinoma.  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