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   19117篇
  免费   1299篇
  国内免费   74篇
耳鼻咽喉   217篇
儿科学   433篇
妇产科学   354篇
基础医学   2631篇
口腔科学   338篇
临床医学   1650篇
内科学   4929篇
皮肤病学   413篇
神经病学   1678篇
特种医学   642篇
外科学   2695篇
综合类   245篇
一般理论   8篇
预防医学   1430篇
眼科学   421篇
药学   1143篇
中国医学   79篇
肿瘤学   1184篇
  2023年   133篇
  2022年   331篇
  2021年   557篇
  2020年   309篇
  2019年   454篇
  2018年   533篇
  2017年   352篇
  2016年   373篇
  2015年   456篇
  2014年   629篇
  2013年   853篇
  2012年   1353篇
  2011年   1375篇
  2010年   791篇
  2009年   673篇
  2008年   1135篇
  2007年   1224篇
  2006年   1188篇
  2005年   1116篇
  2004年   1020篇
  2003年   973篇
  2002年   967篇
  2001年   148篇
  2000年   130篇
  1999年   177篇
  1998年   203篇
  1997年   167篇
  1996年   166篇
  1995年   123篇
  1994年   116篇
  1993年   98篇
  1992年   103篇
  1991年   108篇
  1990年   98篇
  1989年   72篇
  1988年   90篇
  1987年   89篇
  1986年   74篇
  1985年   91篇
  1984年   105篇
  1983年   99篇
  1982年   115篇
  1981年   125篇
  1980年   111篇
  1979年   68篇
  1978年   78篇
  1977年   94篇
  1976年   63篇
  1975年   55篇
  1974年   59篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
PURPOSE: Novel therapies are needed for patients with recurrent glioblastoma multiforme (GBM). Because there is evidence that temozolomide (TMZ) has some activity in GBM and is well tolerated, and because of laboratory evidence that metalloproteinases are important in glioma cell invasion, the combination of TMZ and the matrix metalloproteinase inhibitor marimastat (MRM) in patients with recurrent GBM was studied. PATIENTS AND METHODS: Forty-four patients with recurrent GBM after standard radiotherapy were enrolled. For 19 patients, this therapy was their first chemotherapy after tumor progression after irradiation; 25 others had received chemotherapy previously. TMZ 150 to 200 mg/m(2) days 1 to 5 and MRM 50 mg days 8 to 28 was administered at 28-day intervals for two cycles; then patients were reevaluated. Treatment continued until progression of tumor or toxicity developed. RESULTS: Joint and tendon pain was the major therapy-related toxicity and was reported in 47% of patients. Five patients (11%) were removed from the study because of intolerable joint pain. For all patients, the progression-free survival (PFS) at 6 months was 39%. Median PFS was 17 weeks, median overall survival was 45 weeks, and 12-month PFS was 16%. CONCLUSION: The combination of TMZ and MRM resulted in a PFS at 6 months that exceeded the literature target by 29%. This drug combination met phase II study criteria; further study in recurrent patients with GBM might be warranted. Further study of therapy-induced joint pain is necessary.  相似文献   
992.
PURPOSE: The purpose of this work was to study the sera of patients with lymphoepithelioma-like carcinoma (LELC) of the lung for circulating EBV DNA. EXPERIMENTAL DESIGN: Prospectively collected serum samples from five female patients with advanced, inoperable LELC of the lung were measured for free circulating EBV DNA using a quantitative PCR technique. EBV-encoded small RNA (EBER)-1 was assayed in serial serum samples of three of the five patients, either from the start or during the initial phase of chemotherapy/radiotherapy until their terminal event or last follow-up. There was only a single-point sample for analysis in the fourth and fifth patients. Six other patients with LELC of the lung were also retrospectively identified, and their sera were tested for EBER-1 at either the first visit plus the last follow-up visit (n = 2), the first visit only (n = 2), or the last follow-up visit only (n = 2). RESULTS: Prospectively collected serum samples from five patients and retrospectively collected serum samples from two patients who had clinical disease at initial serum measurement showed detectable levels of EBER-1. Retrospectively collected serum samples from four patients with no clinical disease had negative sera. There is consistent correlation between the clinical response to treatment and subsequent clinical course of LELC and serum EBER-1 levels in the three prospective patients with longitudinal serum monitoring. CONCLUSIONS: This study shows for the first time that free EBV DNA can be detected in the serum of patients with LELC of the lung and further suggests the feasibility of its use for monitoring response to therapy in advanced cases.  相似文献   
993.
Ki-4.dgA is an anti-CD30 immunotoxin (IT) constructed by coupling the monoclonal antibody Ki-4 via a sterically hindered disulfide linker to deglycosylated ricin A-chain. This IT was efficacious in vitro and in SCID mice with disseminated human Hodgkin's lymphoma. Accordingly, a Phase I trial in patients (pts) with Hodgkin's lymphoma was designed. The objectives of this Phase I trial were to determine the maximum tolerated dose, the dose-limiting toxicities, pharmacokinetics, and antitumor activity. Seventeen pts with relapsed CD30+ lymphoma were treated with escalating doses (5, 7.5, or 10 mg/m(2)/cycle) of the IT as four bolus infusions on days 1, 3, 5, and 7 for one to three cycles. All of the pts had progressive disease and were heavily pretreated. Nine had primary progressive disease and 14 had advanced disease with massive tumor burdens. The mean age was 35 years (24-52 years). Peak serum concentrations of the intact IT varied from 0.23 to 1.1 microg/ml. Side effects and dose-limiting toxicities were related to vascular leak syndrome, i.e., decreases in serum albumin, edema, weight gain, hypotension, tachycardia, myalgia, and weakness. The maximum tolerated dose was 5 mg/m(2). Seven of 17 (40%) pts made human antiricin antibodies (> or =1.0 microg/ml), and 1 pt developed human antimouse antibodies (> or =1.0 microg/ml). Clinical response in the 15 evaluable pts included 1 partial remission, 1 minor response, and 2 stable diseases. In conclusion, the IT was less well tolerated than other ITs of this type. This might be because of the low number of CD30+ peripheral blood mononuclear cells, and in part because of binding of the IT to soluble CD30 antigen and the resulting circulation of IT/sCD30 complexes.  相似文献   
994.
995.
BACKGROUND: Paracetamol (N-acetyl-p-amino-phenol) or acetaminophen has become the most widely used analgesic and antipyretic in children. However, there is a wide discrepancy between the extent to which paracetamol is used and the limited available pharmacological data in small infants. The purpose of this article is to present a review of the current literature regarding the use of paracetamol in neonates and infants with a particular emphasis on pharmacological issues. METHODS: A MEDLINE search (up to March 2000) was conducted to identify relevant English-language publications using paracetamol, children, infants and neonates as search terms. Additional studies were identified from bibliographies of the reviewed literature. RESULTS: Pharmacological studies on paracetamol in infants are few. Most studies have focused on the administration of one single paracetamol dose, and the problem of cumulative toxicity with repeated dosing has not been addressed. Plasma paracetamol concentration should be 10-20 mg ml(-1) to achieve antipyretic and analgesic effects. The bioavailability of the different formulations and routes of administration vary with age. Rectal absorption is slower and more erratic than the oral; however, in the very young, rectal bioavailability is higher than in older patients. Volume of distribution seems to be age-independent, whereas clearance is reduced in neonates and particularly in preterm babies. Neonates and infants are capable of forming the reactive intermediate metabolite that causes hepatocellular damage, particularly after multiple doses. They have an immature glucuronide conjugation system, but the rate constant for the sulphation metabolic pathway is larger than in older children, and this is the most important route of metabolism. CONCLUSIONS: The pharmacokinetics and pharmacodynamics of paracetamol differ substantially in neonates and infants from those in older children and adults; hence, dosing should be adjusted accordingly.  相似文献   
996.
It should be recognized that these guidelines should not be deemed inclusive of all proper method of care or exclusive of methods of care reasonably directed to obtaining the same results. The ultimate judgment regarding the propriety of any specific procedure must be made by the physician in light of all of the circumstances presented by the individual patient.Prepared by The Standards Task Force The American Society of Colon and Rectal Surgeons  相似文献   
997.
Breast Cancer Research and Treatment -  相似文献   
998.
The predictive value of intraoperative stimulation thresholds for facial nerve function, using a constant-current system, was examined in 49 patients undergoing resection of cerebellopontine-angle tumors. Immediately after surgery, 75% of the 0.1-mA threshold group, 42% of the 0.2-mA group, and 18% of the 0.3-mA or greater group had good (grade I or II) facial nerve function. One year after surgery, 90% of the 0.1-mA group, 58% of the 0.2-mA group, and 41% of the 0.3-mA or greater group had grade I or II function. A statistically significant breakpoint of 0.2 mA was found to predict good postoperative facial function. Delayed facial paralysis occurred in 22% of patients, but the prognosis for these patients was favorable. Both current stimulation threshold and duration are necessary for a meaningful comparison of data between investigators. Laryngoscope, 106:633-638, 1996  相似文献   
999.
Computer-assisted open catheter studies of 10 healthy, nose-breathing men in dorsal and in lateral recumbent sleep demonstrated stable intrasubject transpharyngeal differential pressures and airflow resistances. They averaged 19.6 Pa (± standard deviation [SD] 11.9) and 0.103 Pa/cm3 per second (± SD 0.065) in the dorsal posture and stage II sleep during quiet breathing and were not significantly different in the lateral posture or in stage I sleep. Five subjects were snorers, and their pharyngeal airflow pressures and resistances increased substantially during quiet breathing on assumption of recumbency and much more in sleep. In the 5 subjects who were nonsnorers, postural changes were not significant and sleep increases were moderate. During snoring, transpharyngeal pressures and resistances increased even further, averaging 188 Pa and 1.02 Pa/cm3 per second for the whole group. Transpharyngeal differential pressures and hypopharyngeal transmural pressures frequently exceeded 300 Pa in inspiration and in expiration during periods of snoring. Yet, transpharyngeal differential pressures and resistances did not reveal appreciable differences between phases that would indicate compliant change of pharyngeal cross section. Breathing frequency was unchanged, but ventilation was significantly diminished at elevated upper airway resistances (P<.01). Transpharyngeal resistances and differential pressures varied independently from widely differing nasal resistances. As with our earlier studies, pressure measurements alone clearly demonstrated breathing patterns and events.  相似文献   
1000.
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