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   4229篇
  免费   249篇
  国内免费   19篇
耳鼻咽喉   86篇
儿科学   79篇
妇产科学   47篇
基础医学   453篇
口腔科学   90篇
临床医学   369篇
内科学   978篇
皮肤病学   227篇
神经病学   388篇
特种医学   126篇
外科学   691篇
综合类   16篇
一般理论   2篇
预防医学   321篇
眼科学   115篇
药学   167篇
中国医学   3篇
肿瘤学   339篇
  2023年   18篇
  2022年   57篇
  2021年   115篇
  2020年   57篇
  2019年   105篇
  2018年   124篇
  2017年   80篇
  2016年   93篇
  2015年   127篇
  2014年   148篇
  2013年   216篇
  2012年   304篇
  2011年   292篇
  2010年   170篇
  2009年   169篇
  2008年   258篇
  2007年   272篇
  2006年   256篇
  2005年   229篇
  2004年   223篇
  2003年   189篇
  2002年   193篇
  2001年   53篇
  2000年   69篇
  1999年   52篇
  1998年   39篇
  1997年   42篇
  1996年   37篇
  1995年   28篇
  1994年   27篇
  1993年   38篇
  1992年   34篇
  1991年   47篇
  1990年   30篇
  1989年   20篇
  1988年   30篇
  1987年   21篇
  1986年   23篇
  1985年   15篇
  1984年   19篇
  1983年   16篇
  1982年   16篇
  1981年   16篇
  1978年   10篇
  1977年   11篇
  1976年   9篇
  1975年   11篇
  1974年   8篇
  1973年   8篇
  1932年   7篇
排序方式: 共有4497条查询结果,搜索用时 15 毫秒
41.
The prevalence of obesity in Araraquara, a county of 150,000 inhabitants situated 250 km from S. Paulo, Brazil was studied. The study population, of 18-74 yrs. of age, resident in the urban area in 1987, was composed of 1,126 inhabitants, 502 males and 624 females, selected through a cluster equiprobabilistic sampling process. The prevalence of overweight (Quetelet 25-29.9 Kg/m2) was 26.9% for males and 27.7% for females. The prevalence of obesity (Quetelet equal or greater than 30.0 kg/m2) was 10.2% for males and 14.7% for females. These percentages are high when compared with those of affluent Anglo-saxon countries. The reasons for this phenomenon are discussed in the light of the fact that the economy of the city is affluent and is dependent on agroindustrial activities. When own cut-off criteria (P85 and P95 for Quetelet for 20-29 yrs of age, for each sex) are calculated, the "lean pattern" for Araraquara County is leaner than that for the a United States population. This raises doubts as to the possibility of applying cut-off criteria of particular regions to regions of different characteristics.  相似文献   
42.
43.
A case of an abdominal cerebrospinal fluid (CSF) pseudocyst in a patient with a ventriculoperitoneal shunt is reported to illustrate this known but rare complication. In the setting of a VP shunt, the frequency of abdominal CSF pseudocyst formation is approximately 3.2%, often being precipitated by a recent inflammatory or infective process or recent surgery. Larger pseudocysts tend to be sterile, whereas smaller pseudocysts are more often infected. Ultrasound and CT each have characteristic findings.  相似文献   
44.
PURPOSE: To assess tolerance and efficacy of preoperative treatment with uracil/tegafur and radiotherapy (RT) followed by surgery and postoperative flurouracil (FU)/leucovorin (LV) in patients with rectal cancer. PATIENTS AND METHODS: Patients (n = 94) with potentially resectable tumors, ultrasound at stages T2N+ (n = 4), T3 (n = 77), T4 (n = 13) were treated with UFT (400 mg/m2/d, 5 days a week for 5 weeks) and concomitant RT to the pelvis (45 Gy; 1.8 Gy/d over 5 weeks). Patients underwent surgery 5 to 6 weeks later followed by four cycles of FU/LV. Primary end points included downstaging, pathologic responses, and sphincter-preserving surgery. Secondary end points were recurrence-free survival and overall survival. RESULTS: All patients received the full RT dose. Fifteen patients (16%) needed UFT dose reduction. Preoperative G3+ toxicities included diarrhea (14%), leukopenia (1%), thrombocytopenia (1%), and nausea (4%). The downstaging rate was 54%, pathologic complete response (pCR) was 9% and, in an additional 23%, there were only residual microscopic foci. When cellular viability criteria were taken into account, the pCR was 15%. From 43 patients with abdominoperineal resection indication, 11 (25%) had sphincter-preserving surgery performed. Postoperative scheduled chemotherapy dose was not administered to 24% of patients because of G3+ toxicity (diarrhea, 8%; mucositis, 9%; and leukopenia, 7%). Patients with downstaging had significantly higher survival and recurrence-free survival rates than those without. At 3 years, actuarial patterns of failure were pelvic, 5% and distant, 11%. OS was 75%. CONCLUSION: UFT combined with RT is safe and effective. In resectable rectal cancer, if preoperative treatment is considered, this approach can be an option.  相似文献   
45.
PURPOSE: T-Cell lymphomas constitute heterogeneous and aggressive tumors in which pathogenic alterations remain largely unknown. Expression profiling has demonstrated to be a useful tool for molecular classification of tumors. EXPERIMENTAL DESIGN: Using DNA microarrays (CNIO-OncoChip) containing 6386 cancer-related genes, we established the expression profiling of T-cell lymphomas and compared them to normal lymphocytes and lymph nodes. RESULTS: We found significant differences between the peripheral and lymphoblastic T-cell lymphomas, which include a deregulation of nuclear factor-kappaB signaling pathway. We also identify differentially expressed genes between peripheral T-cell lymphoma tumors and normal T lymphocytes or reactive lymph nodes, which could represent candidate tumor markers of these lymphomas. Additionally, a close relationship between genes associated to survival and those that differentiate among the stages of disease and responses to therapy was found. CONCLUSIONS: Our results reflect the value of gene expression profiling to gain insight about the molecular alterations involved in the pathogenesis of T-cell lymphomas.  相似文献   
46.
PURPOSE: Diflomotecan (BN80915) is an E-ring modified camptothecin analogue that possesses greater lactone stability in plasma compared with other topoisomerase I inhibitors, a potential advantage for antitumor activity. As with other camptothecins, oral administration has pharmacological and clinical advantages. This Phase I study was performed to assess the feasibility of the administration of oral diflomotecan, to determine the maximum-tolerated, dose its bioavailability, and to explore the pharmacokinetics. EXPERIMENTAL DESIGN: An initial i.v. bolus was administered to assess the bioavailability of diflomotecan. Fourteen days later, diflomotecan was administered p.o. once daily for 5 days to adult patients with solid malignant tumors and repeated every 3 weeks. BN80915 and its open lactone form BN80942 were measured. RESULTS: Twenty-two patients entered the study and received a total of 57 cycles of oral diflomotecan at flat dose levels of 0.10, 0.20, 0.27, and 0.35 mg. The main toxicity was hematological, but some patients experienced alopecia, mild gastrointestinal toxicity, and fatigue. At the 0.35-mg dose level, 2 of 4 patients experienced dose-limiting toxicity comprising grade 3 thrombocytopenia with epistaxis and febrile neutropenia in 1 patient and uncomplicated grade 4 neutropenia lasting for >7 days in another. Toxicity was acceptable at the 0.27-mg dose level at which dose-limiting toxicities were observed in 3 of 12 patients (grade 4 neutropenia > 7 days, complicated by fever in 1 patient but without other signs of infection). After two cycles of diflomotecan, 6 patients had disease stabilization, which was maintained in 2 patients for 9 months and >1 year, respectively. Diflomotecan pharmacokinetics were linear over the dose range studied. Systemic exposure correlated with the fall in WBC counts. The mean oral bioavailability (+/-SD) was 72.24 +/- 59.2% across all dose levels. Urinary excretion of BN80915 was very low. CONCLUSIONS: The recommended oral diflomotecan dose for Phase II studies is 0.27 mg/day x 5 every 3 weeks. This regimen is convenient and generally well tolerated with a favorable pharmacokinetic profile and high but variable bioavailability.  相似文献   
47.
Postoperative speech function may be influenced by a number of treatment variables. The objective of this study was to examine the relationships among various treatment factors to determine the impact of these measures on speech function. Speech function was tested prospectively in 142 patients with surgically treated oral and oropharyngeal cancer 3 months after treatment. Each patient's speech was recorded during a 6- to 7-minute conversation and while performing a standard articulation test, producing speech outcome measures of percent correct consonant phonemes and percent conversational understandability. Correlational analyses were used to determine the relationships among the speech outcome measures and 14 treatment parameters. Speech function was mildly to moderately negatively correlated with most surgical resection variables, indicating that larger amounts of tissue resected were associated with worse speech function. Overall measures of conversational understandability and percent correct consonant phonemes were related to extent of oral tongue resection, floor of mouth resection, soft palate resection, and total volume of tissue resected. These relationships varied depending on the method of surgical closure. Method of surgical reconstruction had a profound impact on postoperative speech function 3 months after treatment and was an important factor in determining how oral tongue resection influenced articulation and intelligibility. The combination of closure type, percent oral tongue resected, and percent soft palate resected had the strongest relationship with overall speech function for patients with surgically treated oral and oropharyngeal cancer 3 months after treatment.  相似文献   
48.
49.
Since 1993 in Portugal, it is possible, by legal enforcement, to request forensic examination to study possible conditions of drug addiction. On the basis of examinations carried out in the Medico Legal Institute of Oporto, we present a study of 494 cases involving the relation to the demographic data of the examined individuals, their family background, legal situation, age at which drug consumption began, consumption profile at the beginning and at time of forensic examination and our conclusions.  相似文献   
50.
PURPOSE: Cancer-testis genes mapping to the X chromosome have common expression patterns and show similar responses to modulators of epigenetic mechanisms. We asked whether cancer-testis gene expression occurred coordinately, and whether it correlated with variables of disease and clinical outcome of non-small cell lung cancer (NSCLC). EXPERIMENTAL DESIGN: Tumors from 523 NSCLC patients undergoing surgery were evaluated for the expression of nine cancer-testis genes (NY-ESO-1, LAGE-1, MAGE-A1, MAGE-A3, MAGE-A4, MAGE-A10, CT7/MAGE-C1, SSX2, and SSX4) by semiquantitative PCR. Clinical data available for 447 patients were used to correlate cancer-testis expression to variables of disease and clinical outcome. RESULTS: At least one cancer-testis gene was expressed by 90% of squamous carcinoma, 62% of bronchioloalveolar cancer, and 67% of adenocarcinoma samples. Statistically significant coexpression was observed for 34 of the 36 possible cancer-testis combinations. Cancer-testis gene expression, either cumulatively or individually, showed significant associations with male sex, smoking history, advanced tumor, nodal and pathologic stages, pleural invasion, and the absence of ground glass opacity. Cox regression analysis revealed the expression of NY-ESO-1 and MAGE-A3 as markers of poor prognosis, independent of confounding variables for adenocarcinoma of the lung. CONCLUSIONS: Cancer-testis genes are coordinately expressed in NSCLC, and their expression is associated with advanced disease and poor outcome.  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