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   7053篇
  免费   341篇
  国内免费   40篇
耳鼻咽喉   66篇
儿科学   131篇
妇产科学   37篇
基础医学   964篇
口腔科学   309篇
临床医学   382篇
内科学   1609篇
皮肤病学   187篇
神经病学   565篇
特种医学   290篇
外科学   1314篇
综合类   28篇
一般理论   1篇
预防医学   226篇
眼科学   92篇
药学   355篇
中国医学   16篇
肿瘤学   862篇
  2023年   37篇
  2022年   87篇
  2021年   129篇
  2020年   61篇
  2019年   80篇
  2018年   138篇
  2017年   117篇
  2016年   145篇
  2015年   140篇
  2014年   177篇
  2013年   227篇
  2012年   311篇
  2011年   351篇
  2010年   218篇
  2009年   188篇
  2008年   309篇
  2007年   353篇
  2006年   351篇
  2005年   319篇
  2004年   318篇
  2003年   286篇
  2002年   292篇
  2001年   266篇
  2000年   247篇
  1999年   211篇
  1998年   92篇
  1997年   48篇
  1996年   48篇
  1995年   50篇
  1994年   36篇
  1993年   48篇
  1992年   144篇
  1991年   126篇
  1990年   126篇
  1989年   132篇
  1988年   104篇
  1987年   111篇
  1986年   98篇
  1985年   90篇
  1984年   87篇
  1983年   70篇
  1979年   76篇
  1978年   40篇
  1977年   34篇
  1973年   40篇
  1971年   34篇
  1970年   38篇
  1969年   41篇
  1968年   41篇
  1967年   48篇
排序方式: 共有7434条查询结果,搜索用时 15 毫秒
111.
Liver metastasis of primary tumor is a clinically major problem. KRN7000, an alpha-galactosylceramide, significantly augments natural killer (NK) activity of spleen cells and shows strong antitumor activity in mice with lung metastasis of melanoma B16 cells. To test whether KRN7000 has an antitumor activity in mice with hepatic metastasis of tumors, we examined the effect of KRN7000 on NK activity of hepatic mononuclear cells (MNC) and the antitumor activity in mice with liver metastasis of EL-4 cells. The in vivo administration of KRN7000 significantly augmented NK activity of hepatic MNC and inhibited tumor growth of EL-4 cells in the liver more markedly than chemotherapeutic agents, leading to a relatively high rate of cured mice. In addition, it appeared that the KRN7000 treatment is effective in mice with established EL-4 tumors. Moreover, we found that KRN7000 can produce significant amounts of interleukin 2 (IL-2), IL-4, IL-12, and interferon-gamma in a dose-dependent manner. These results suggest that KRN7000 will be useful for the treatment of cancer liver metastasis.  相似文献   
112.
CONTEXT: Several reports from small clinical trials have suggested that estrogen replacement therapy may be useful for the treatment of Alzheimer disease (AD) in women. OBJECTIVE: To determine whether estrogen replacement therapy affects global, cognitive, or functional decline in women with mild to moderate AD. DESIGN: The Alzheimer's Disease Cooperative Study, a randomized, double-blind, placebo-controlled clinical trial conducted between October 1995 and January 1999. SETTING: Thirty-two study sites in the United States. PARTICIPANTS: A total of 120 women with mild to moderate AD and a Mini-Mental State Examination score between 12 and 28 who had had a hysterectomy. INTERVENTIONS: Participants were randomized to estrogen, 0.625 mg/d (n = 42), or 1.25 mg/d (n = 39), or to identically appearing placebo (n = 39). One subject withdrew after randomization but before receiving medication; 97 subjects completed the trial. MAIN OUTCOME MEASURES: The primary outcome measure was change on the Clinical Global Impression of Change (CGIC) 7-point scale, analyzed by intent to treat; secondary outcome measures included other global measures as well as measures of mood, specific cognitive domains (memory, attention, and language), motor function, and activities of daily living; compared by the combined estrogen groups vs the placebo group at 2, 6, 12, and 15 months of follow-up. RESULTS: The CGIC score for estrogen vs placebo was 5.1 vs 5.0 (P = .43); 80% of participants taking estrogen vs 74% of participants taking placebo worsened (P = .48). Secondary outcome measures also showed no significant differences, with the exception of the Clinical Dementia Rating Scale, which suggested worsening among patients taking estrogen (mean posttreatment change in score for estrogen, 0.5 vs 0.2 for placebo; P = .01). CONCLUSIONS: Estrogen replacement therapy for 1 year did not slow disease progression nor did it improve global, cognitive, or functional outcomes in women with mild to moderate AD. The study does not support the role of estrogen for the treatment of this disease. The potential role of estrogen in the prevention of AD, however, requires further research.  相似文献   
113.
Nio  M.  Sano  N.  Kotera  A.  李丹 《世界核心医学期刊文摘》2006,2(2):42-42
作者报道1例患原发性气管雪旺细胞瘤(神经鞘瘤)的9岁女患儿合并气道梗阻。CT扫描发现气管内多息肉样肿块,73%的管腔发生梗阻。行气管部分切除及吻合术。病检确诊为起源于雪旺细胞的良性神经源性肿瘤。9岁女患儿的原发性气管雪旺细胞瘤(神经鞘瘤)@Nio M. @Sano N. @Kotera  相似文献   
114.
A new simply and effective fractionation method for cylindrospermopsin (CYN) analyses was developed. The extract from cells of Cylindrospermopsis raciborskii was resuspended with 0.1 M carbonate buffer at pH 10.5, and pass through the double-cartridges column which was consisted of a styrene polymer cartridge and an anion exchange cartridge. CYN and deoxy-CYN were adsorbed with the anion exchange cartridge. After separation of the anion exchange cartridge, adsorbed compounds were eluted from the cartridge with 50% methanol containing 1% formic acid solution. CYN and deoxy-CYN were selectively condensed in the eluted solution. When CYN was analyzed by LC-photodiode array or LC/MS, only two peaks of CYN and deoxy-CYN were detected quantitatively. The results suggest that the fractionation method is a useful method for CYN analyses and must be utilized for CYN purification.  相似文献   
115.
Although still controversial, iron deficiency has been indicated as one of the risk factors for developing neuroleptic-induced extrapyramidal symptoms (EPSs), including akathisia, dystonia, and neuroleptic malignant syndrome. Here we report our experience of iron supplementation and alternating neuroleptics for treating Parkinsonism in a schizophrenic female patient having severe iron deficient anemia.  相似文献   
116.
Vascular endothelial growth factor receptor 2 (VEGFR2) is an essential factor in tumor angiogenesis and in the growth of pancreatic cancer. Immunotherapy using epitope peptide for VEGFR2 (VEGFR2‐169) that we identified previously is expected to improve the clinical outcome. Therefore, a phase I clinical trial combining of VEGFR2‐169 with gemcitabine was conducted for patients with advanced pancreatic cancer. Patients with metastatic and unresectable pancreatic cancer were eligible for the trial. Gemcitabine was administered at a dose of 1000 mg/m2 on days 1, 8, and 15 in a 28‐day cycle. The VEGFR2‐169 peptide was subcutaneously injected weekly in a dose‐escalation manner (doses of 0.5, 1, and 2 mg/body, six patients/one cohort). Safety and immunological parameters were assessed. No severe adverse effect of grade 4 or higher was observed. Of the 18 patients who completed at least one course of the treatment, 15 (83%) developed immunological reactions at the injection sites. Specific cytotoxic T lymphocytes (CTL) reacting to the VEGFR2‐169 peptide were induced in 11 (61%) of the 18 patients. The disease control rate was 67%, and the median overall survival time was 8.7 months. This combination therapy for pancreatic cancer patients was tolerable at all doses. Peptide‐specific CTL could be induced by the VEGFR2‐169 peptide vaccine at a high rate, even in combination with gemcitabine. From an immunological point of view, the optimal dose for further clinical trials might be 2 mg/body or higher. This trial was registered with ClinicalTrial.gov (no. NCT 00622622). (Cancer Sci 2009)  相似文献   
117.
PURPOSE: Nitroglycerin may improve the response to chemotherapy in advanced non-small cell lung cancer. The effects and mechanisms of nitroglycerin on the enhancement of chemosensitivity to docetaxel and carboplatin regimen (DCb) in patients with lung adenocarcinoma have not been reported. EXPERIMENTAL DESIGN: Seventeen patients with operable lung adenocarcinoma and stable angina pectoris were selected to investigate the effects of nitroglycerin on immunoreactivity for hypoxia-inducible factor 1alpha (HIF-1alpha), vascular endothelial growth factor (VEGF), P-glycoprotein (P-gp), the production of which is regulated by HIF-1, and p53 proteins in their resected tumor by semiquantitative immunohistochemical analyses. Eight of 17 patients were treated with nitroglycerin patches before operation, but 9 of 17 patients were not. Furthermore, to study the relationship between changes in plasma VEGF levels by nitroglycerin treatment and response to DCb, 29 patients with advanced lung adenocarcinoma were treated with nitroglycerin for 3 days before chemotherapy using DCb. RESULTS: The rates of immunoreactive cells for HIF-1alpha, VEGF, and P-gp in tumor tissues treated with nitroglycerin were lower than those without nitroglycerin, but those for p53 were not different between those treated with and without nitroglycerin. Furthermore, the rates of immunoreactive cells for VEGF and P-gp proteins were significantly associated with those for HIF-1alpha in tumor tissue. The magnitude of decrease in plasma VEGF levels after treatment with nitroglycerin was significantly associated with response to DCb in patients with advanced lung adenocarcinoma. CONCLUSIONS: Nitroglycerin treatment may improve response to DCb in patients with lung adenocarcinoma, partly through decreasing VEGF and P-gp production via reduction of HIF-1alpha.  相似文献   
118.
Serum pepsinogen levels were measured in 137 stomach cancer patients and compared with those of 288 normal cancer-free subjects. The serum pepsinogen levels of stomach cancer patients, especially pepsinogen I and the pepsinogen I/pepsinogen II ratio were significantly lower than those of normal controls and correlated well with the extent of chronic gastritis associated with the cancerous stomach. These results were in good accordance with the results of previous studies indicating that the cancer derived from the stomach where chronic gastritis/intestinal metaplasia is extensive. The high sensitivity and specificity of this non-invasive serum test to detect chronic gastritis suggested the possibility of its application to the mass screening of stomach cancer.  相似文献   
119.

BACKGROUND:

The seventh TNM staging system for gastric cancer of the American Joint Committee on Cancer/International Union Against Cancer (AJCC/UICC) had a more detailed classification than the sixth TNM staging system for both the tumor (T) and lymph nodes (N). The authors compared survival rates assessed by the seventh staging system with those by the sixth system.

METHODS:

The authors analyzed the prospectively collected database on patients with gastric cancer who underwent surgery at Seoul National University Hospital between 1986 and 2006, and calculated the survival rates of 9998 cases with primary cancer, R0 resection, and >14 retrieved lymph nodes.

RESULTS:

The 5‐year cumulative survival rates (5YSR) according to the seventh edition T or N classifications were significantly different. The 5YSR according to seventh edition of the TNM staging system were 95.1% (stage IA), 88.4% (stage IB), 84.0% (stage IIA), 71.7% (stage IIB), 58.4% (stage IIIA), 41.3% (stage IIIB), and 26.1% (stage IIIC), which were significantly different from each other. The 5YSR of the seventh edition T2 and T3 classifications had significant differences in patients with every N classification, and the 5YSR of seventh edition N1 and N2 classifications had significant differences in T2 patients, T3 patients, and T4 patients. Each stage in the sixth edition was divided into the seventh edition stage with different survival rates. In addition, the number of homogenous groupings in seventh edition TNM stages was increased from 1 to 2.

CONCLUSIONS:

The seventh system provided a more detailed classification of prognosis than the sixth system, especially between T2 and T3 tumors and N1 and N2 tumors, although further studies were found to be needed for the N3a and N3b classification. Cancer 2010. © 2010 American Cancer Society.  相似文献   
120.
Although osteoporotic patients have already been recognized as having a low-volume vitamin D status, the concentration of active vitamin D precursor has not been studied in detail. This trial aimed to clarify the concentration of 25-hydroxyvitamin D (25-OHD), which is a natural type of vitamin D and compare between 2 separate areas in Japan. To compare and clarify the concentration of 25-OHD between 2 separate areas, Japanese patients who were diagnosed as having osteoporosis based on bone mineral density were studied. We analyzed 2 different hospitals’ patients whose residence is separated into a northern district (Akita city: north latitude 39” 43’) and a southern district (Shizuoka city: north latitude 34” 58’). Both of them have completely different daylight hours. Three-hundred sixty eight patients (174 in Akita, 194 in Shizuoka) were enrolled in this trial to compare the differences of concentration of 25-OHD by Welch’s t t-test. There were significant differences in the concentration of 25-OHD and age between them. Akita patients were significantly higher than that of Shizuoka patients despite Shizuoka having much daylight hours of Akita. In conclusion, there might be no relationship between the concentration of 25 OHD and exposure to sunlight.  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