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   2376833篇
  免费   195234篇
  国内免费   4238篇
耳鼻咽喉   34278篇
儿科学   72796篇
妇产科学   62987篇
基础医学   335152篇
口腔科学   67571篇
临床医学   215812篇
内科学   469139篇
皮肤病学   47954篇
神经病学   200896篇
特种医学   96039篇
外国民族医学   886篇
外科学   360721篇
综合类   56259篇
现状与发展   2篇
一般理论   977篇
预防医学   190737篇
眼科学   55502篇
药学   177662篇
  4篇
中国医学   4377篇
肿瘤学   126554篇
  2018年   24285篇
  2016年   20632篇
  2015年   23359篇
  2014年   33627篇
  2013年   50962篇
  2012年   68862篇
  2011年   72422篇
  2010年   42579篇
  2009年   40949篇
  2008年   68872篇
  2007年   73210篇
  2006年   74128篇
  2005年   72150篇
  2004年   69426篇
  2003年   67100篇
  2002年   66338篇
  2001年   112496篇
  2000年   116555篇
  1999年   98359篇
  1998年   27868篇
  1997年   25533篇
  1996年   25456篇
  1995年   24614篇
  1994年   23172篇
  1993年   21559篇
  1992年   79400篇
  1991年   76415篇
  1990年   73589篇
  1989年   70854篇
  1988年   65867篇
  1987年   64823篇
  1986年   61348篇
  1985年   58413篇
  1984年   44235篇
  1983年   37672篇
  1982年   22897篇
  1981年   20340篇
  1980年   19039篇
  1979年   41308篇
  1978年   28990篇
  1977年   24354篇
  1976年   22836篇
  1975年   23969篇
  1974年   29643篇
  1973年   28042篇
  1972年   26228篇
  1971年   24154篇
  1970年   22753篇
  1969年   21092篇
  1968年   19136篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Three patients with hydrocephalus aged 16, 26, and 33 years demonstrated memory deficits before or after the insertion of a ventricular shunt but at no time demonstrated ataxia, incontinence, or dementia. Following shunt surgery, memory functions improved rapidly in the patient who had had a recent acute onset of hydrocephalus, but in the two patients with a long period of hydrocephalus before shunting, memory impairments did not recover significantly in one patient, and in the other, memory impairments had become more severe by 12 months postshunt. Other neuropsychological and psychological sequelae of adult hydrocephalus are discussed, and it is suggested that for patients with chronic hydrocephalus, an extended period of neurological and neuropsychological monitoring may be advantageous before a decision is made to perform shunt surgery.  相似文献   
992.
993.
994.
995.
996.
Bone turnover before and after withdrawal of estrogen/gestagen treatment was studied in a randomized trial with 110 healthy female volunteers, who had passed a natural menopause 6 months to 3 years before the start of the study. Urinary excretion of intravenously injected 99m-technetium diphosphonate was measured as an index of bone turnover; plasma bone Gla protein and serum alkaline phosphatase were measured as indices of bone formation; and fasting urinary excretion of hydroxyproline and calcium were measured as estimates of bone resorption. During 2 years of hormone treatment, all variables decreased highly significantly (p less than 0.001) to a constant low level. Three months after withdrawal all variables increased highly significantly (p less than 0.001) towards, but not above, pretreatment and placebo levels. We conclude that withdrawal of estrogen/gestagen replacement therapy in postmenopausal women increases bone turnover, but not in excess of pretreatment values. This indicates that bone loss (after withdrawal) is similar to that seen in the placebo group and that a rebound phenomenon is unlikely.  相似文献   
997.
OBJECTIVE: According to a report published by the federation of Dutch patients' associations, patients would like to see a pharmacist, who acts more as a personal adviser. This raised the question, how often Dutch community pharmacists have personal consultations with their patients in daily practice, on which factors this depends, and what kind of topics are discussed during these meetings. SETTING: Community pharmacies in the Netherlands. METHOD: A questionnaire was distributed among 800 randomly selected pharmacies. Questions were restricted to consultations characterized by one-to-one contact, drug therapy related content, and adequate privacy. These consultations were labelled as pharmaceutical consultations in private to distinguish them from other contacts between pharmacists and patients. MAIN OUTCOME MEASURE: Number, content, and character of consultations. RESULTS: 198 (24.8%) community pharmacies responded. The pharmacists provide an average of roughly 1.2 consultations in private per working day. The vast majority of respondents provided face-to-face and telephone consultations (94.4 and 91.9%, respectively), only a minority gave consultations by e-mail (30.8%). These consultations primarily dealt with topics related to medication safety. The mean overall time spent was 290 min per month. A relatively high frequency of personal consultations was significantly associated with the absolute number of full-time equivalent pharmacists in the pharmacy. CONCLUSION: The frequency of pharmaceutical consultations in private is low, but may be improved by reorganisation of the pharmacist's activities. The possibility of personal consultations by e-mail is not yet well-developed. Further research is needed to assess the patient's view of pharmaceutical consultations in private.  相似文献   
998.
PURPOSE: The aim of this study was to verify hyperthermia treatment planning calculations by means of measurements performed during hyperthermia treatments. The calculated specific absorption rate (SAR(calc)) was compared with clinically measured SAR values, during 11 treatments in seven cervical carcinoma patients. METHODS: Hyperthermia treatments were performed using the 70 MHz AMC-4 waveguide system. Temperatures were measured using multisensor thermocouple probes. One invasive thermometry catheter in the cervical tumour and two non-invasive catheters in the vagina were used. For optimal tissue contact and fixation of the catheters, a gynaecological tampon was inserted, moisturized with distilled water (4 treatments), or saline (6 treatments) for better thermal contact. During one treatment no tampon was used. At the start of treatment the temperature rise (DeltaT(meas)) after a short power pulse was measured, which is proportional to SAR(meas). The SAR(calc) along the catheter tracks was extracted from the calculated SAR distribution and compared with the DeltaT(meas)-profiles. RESULTS: The correlation between DeltaT(meas) and SAR(calc) was on average R = 0.56 +/- 0.28, but appeared highly dependent on the wetness of the tampon (preferably with saline) and the tissue contact of the catheters. Correlations were strong (R approximately 0.85-0.93) when thermal contact was good, but much weaker (R approximately 0.14-0.48) for cases with poor thermal contact. CONCLUSION: Good correlations between measurements and calculations were found when tissue contact of the catheters was good. The main difficulties for accurate verification were of clinical nature, arising from improper use of the gynaecological tampon. Poor thermal contact between thermocouples and tissue caused measurement artefacts that were difficult to correlate with calculations.  相似文献   
999.
PURPOSE: Bevacizumab, a monoclonal antibody against vascular endothelial growth factor, increases survival when combined with irinotecan-based chemotherapy in first-line treatment of metastatic colorectal cancer (CRC). This randomized, phase II trial compared bevacizumab plus fluorouracil and leucovorin (FU/LV) versus placebo plus FU/LV as first-line therapy in patients considered nonoptimal candidates for first-line irinotecan. PATIENTS AND METHODS: Patients had metastatic CRC and one of the following characteristics: age > or = 65 years, Eastern Cooperative Oncology Group performance status 1 or 2, serum albumin < or = 3.5 g/dL, or prior abdominal/pelvic radiotherapy. Patients were randomly assigned to FU/LV/placebo (n = 105) or FU/LV/bevacizumab (n = 104). The primary end point was overall survival. Secondary end points were progression-free survival, response rate, response duration, and quality of life. Safety was also assessed. RESULTS: Median survival was 16.6 months for the FU/LV/bevacizumab group and 12.9 months for the FU/LV/placebo group (hazard ratio, 0.79; P = .16). Median progression-free survival was 9.2 months (FU/LV/bevacizumab) and 5.5 months (FU/LV/placebo); hazard ratio was 0.50; P = .0002. Response rates were 26.0% (FU/LV/bevacizumab) and 15.2% (FU/LV/placebo) (P = .055); duration of response was 9.2 months (FU/LV/bevacizumab) and 6.8 months (FU/LV/placebo); hazard ratio was 0.42; P = .088. Grade 3 hypertension was more common with bevacizumab treatment (16% v 3%) but was controlled with oral medication and did not cause study drug discontinuation. CONCLUSION: Addition of bevacizumab to FU/LV as first-line therapy in CRC patients who were not considered optimal candidates for first-line irinotecan treatment provided clinically significant patient benefit, including statistically significant improvement in progression-free survival.  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