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   6935篇
  免费   488篇
  国内免费   61篇
耳鼻咽喉   40篇
儿科学   147篇
妇产科学   118篇
基础医学   1027篇
口腔科学   106篇
临床医学   631篇
内科学   1795篇
皮肤病学   154篇
神经病学   814篇
特种医学   183篇
外科学   630篇
综合类   15篇
一般理论   4篇
预防医学   433篇
眼科学   73篇
药学   553篇
中国医学   14篇
肿瘤学   747篇
  2024年   7篇
  2023年   73篇
  2022年   173篇
  2021年   287篇
  2020年   145篇
  2019年   181篇
  2018年   260篇
  2017年   184篇
  2016年   206篇
  2015年   262篇
  2014年   298篇
  2013年   358篇
  2012年   579篇
  2011年   607篇
  2010年   303篇
  2009年   272篇
  2008年   469篇
  2007年   486篇
  2006年   425篇
  2005年   427篇
  2004年   364篇
  2003年   373篇
  2002年   278篇
  2001年   58篇
  2000年   41篇
  1999年   41篇
  1998年   35篇
  1997年   27篇
  1996年   27篇
  1995年   21篇
  1994年   18篇
  1993年   14篇
  1992年   17篇
  1991年   17篇
  1990年   17篇
  1989年   20篇
  1988年   11篇
  1987年   10篇
  1986年   16篇
  1985年   10篇
  1984年   8篇
  1983年   11篇
  1982年   3篇
  1981年   3篇
  1980年   7篇
  1979年   8篇
  1978年   3篇
  1976年   6篇
  1975年   5篇
  1971年   4篇
排序方式: 共有7484条查询结果,搜索用时 0 毫秒
91.
OBJECTIVE: TGPO autoantibodies (aAbs) that bind simultaneously to thyroglobulin (Tg) and thyroperoxidase (TPO) are present in the serum of patients with autoimmune thyroid diseases (AITD) and have been found to differ from monospecific Tg and TPO aAbs. To obtain further insights on the prevalence defined as the rate of occurrence and significance of TGPO aAbs in a large population, we carried out a collaborative study involving 15 European teams. METHODS: Serum samples from 3122 patients with various thyroid and non-thyroid diseases and normal subjects were assayed using a novel TGPO aAb detection kit. This test was designed so that TGPO aAbs are trapped between the Tg-coated solid phase and the soluble TPO labeled with a radioiodinated monoclonal antibody. RESULTS: Only three out of the 220 normal subjects (prevalence of 1.4%) were found to have positive TGPO aAb levels, which were mainly observed in the patients with AITD: the group of patients suffering from Hashimoto's thyroiditis had a TGPO aAb prevalence of 40.5% (n=437 patients), those with Graves' disease, a prevalence of 34.6% (n=645) and those with post-partum thyroiditis, 16.0% (n=243). Among the non-AITD patients with positive TGPO aAb levels, the TGPO aAb prevalence ranged from 20.7% among those with thyroid cancer (n=246) to 0% among those with toxic thyroid nodules (n=47). Among the patients with non-thyroid diseases, the TGPO aAb prevalence ranged from 9.8% in the case of Biermer's pernicious anemia (n=78) to 0% in that of premature ovarian failure (n=44). It is worth noting that the groups showing the highest TGPO aAb prevalence also contained the patients with the highest TGPO aAb titers. Statistical comparisons between the TGPO aAb prevalences in the various groups showed that TGPO aAb could be used as a parameter to distinguish between the groups of Hashimoto's and Graves' patients and between the women with post-partum thyroiditis and the post-partum women with only Tg and/or TPO aAb established during early pregnancy. Unexpectedly, the correlations between TGPO aAbs and Tg and TPO aAbs were found to depend mainly on the assay kit used. CONCLUSION: High TGPO aAb titers are consistently associated with AITD but the reverse was not found to be true. TGPO aAbs are a potentially useful tool, however, for establishing Hashimoto's diagnosis, and would be worth testing in this respect with a view to using them for routine AITD investigations.  相似文献   
92.
BACKGROUND: Although risk assessment charts have been proposed to identify patients at high cardiovascular risk, in everyday practice general practitioners (GPs) often use their knowledge of the patients to estimate the risk subjectively. DESIGN: A cross-sectional study aimed to describe how GPs perceive, qualify and grade cardiovascular risk in everyday practice. METHODS: General practitioners had to identify in a random sample of 10% of their contacts the first 20 consecutive patients perceived as being at cardiovascular risk. For each patient essential data were collected on clinical history, physical examination and laboratory tests, for the qualification of risk. At the end of the process GPs subjectively estimated the overall patient's level of risk. General practitioners grading was compared with the risk estimate from a reference chart. RESULTS: Over a mean time of 25 days 3120 patients perceived as being at cardiovascular risk were enrolled. According to the inclusion scheme each GP had contact with more than 200 patients at cardiovascular risk every month. Thirty percent of these patients had atherosclerotic diseases. Up to 72% of patients without any history of atherosclerotic diseases but perceived to be at risk could be classified according to a reference chart as being at moderate to very high risk. Comparing GPs' grading of risk with a chart estimate there was agreement in 42% of the cases. Major determinants of GPs' underestimation of risk were age, sex and smoking habits, while obesity and family history were independently associated with overestimation. CONCLUSIONS: On the basis of their perception GPs properly identify patients at cardiovascular risk in the majority of cases. General practitioners subjective grading of risk level only partially agreed with that given by a chart.  相似文献   
93.
Hemozoin, the detoxification product of hemoglobin heme, piles up as electron-dense material in the food vacuole (FV) of intraerythrocytic malaria parasites (malaria pigment). In infected individuals, pigment is internalized by both circulating and resident phagocytes, thus modulating their functions. Synthetic beta-hematin, prepared in vitro from hematin (ferriprotoporphyrin IX hydroxide) in acidic condition, is spectroscopically identical to hemozoin. In this electron microscopy study, native and synthetic hemozoin also prove to be morphologically indistinguishable (large polygonal crystals with apparent transverse banding) and to undergo the same process when internalized by phagocytes (primarily a direct uptake of crystals, similar to what is described for asbestos fibers). On the contrary,whole parasites appear to follow a classical endocytic pathway. This suggests that there may be differences between the ingestion of free particles and whole parasites in terms of modulation of phagocytes' functions.  相似文献   
94.
95.
96.
97.
A 60-year-old male was admitted to our hospital for gastric cancer. Considering his general condition, total gastrectomy and dissection of regional lymph nodes were performed. Macroscopically, a 45 mm × 20 mm × 10 mm-sized, ulcero-infiltrative tumor located in the esophagogastric junction was described. Microscopically, the tumor consisted of a poorly differentiated adenocarcinoma intermingled with dense lymphoid infiltration predominantly composed of T-cell lymphocytes. The tumor cells infiltrated the submucosa, muscularis and subserosal layers of the stomach, respectively the esophageal adventitia. No metastases were noticed in the 58 regional lymph nodes. Based on the histopathological features, the diagnosis was lymphoepithelioma-like carcinoma, pT3N0 stage. In situ hybridization for Epstein–Barr virus showed no nuclear signal in tumor cells. The p53 expression was observed in fewer than 10% of the tumor cells. Real-time PCR analysis showed microsatellite instability without K-ras mutation in codon 12. No recurrences or metastases were reported 6 months after surgical intervention. No adjuvant therapy was performed.  相似文献   
98.
Neurological Sciences - Monoclonal antibodies targeting the calcitonin gene-related peptide, including erenumab, are migraine-specific preventive treatments, whose long-term effectiveness has still...  相似文献   
99.
International Journal of Mental Health and Addiction - Even though positive associations among problematic Internet use (PIU), maladaptive personality traits, insecure attachment styles, and...  相似文献   
100.
The aim of this study was to determine the impact of prognostic factors in primary fallopian tube carcinoma (PFTC). All cases of PFTC diagnosed between 1990 and 2010 were retrieved from the files of 6 academic centers. The cases were staged according to a modification of the International Federation of Obstetrics and Gynecology staging system proposed by Alvarado-Cabrero et al (Gynecol Oncol 1999; 72: 367–379). One hundred twenty-seven PFTC cases were identified. The mean age of the patients was 64.2 years. Stage distribution was as follows: 72 (57%), stage I; 19 (15%), stage II; 28 (22%), stage III; and 8 (6.2%), stage IV. Depth of infiltration of the tubal wall was an independent prognostic factor in stage I cases (P < .001). Carcinomas located in the fimbriated end even without invasion had a worse prognosis than did carcinomas involving the tubal portion of the organ. The presence of vascular space invasion correlated with the depth of tubal wall invasion (P = .001) and the presence of lymph node metastases (P = .003). Tumor grade significantly correlated with survival (P < .0001), but histologic type was of marginal significance and only if it was grouped as nonserous/non–clear cell vs serous/clear cell (P = .04). The depth of invasion of the tubal wall and the presence of carcinoma in the fimbriated end even without invasion are important prognostic indicators. The modified International Federation of Obstetrics and Gynecology staging system should be used on a routine basis in all carcinomas of the fallopian tube.  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