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   1856篇
  免费   91篇
  国内免费   27篇
耳鼻咽喉   21篇
儿科学   64篇
妇产科学   89篇
基础医学   233篇
口腔科学   34篇
临床医学   127篇
内科学   451篇
皮肤病学   19篇
神经病学   124篇
特种医学   155篇
外科学   261篇
综合类   26篇
预防医学   109篇
眼科学   20篇
药学   84篇
肿瘤学   157篇
  2023年   9篇
  2022年   15篇
  2021年   37篇
  2020年   16篇
  2019年   32篇
  2018年   41篇
  2017年   38篇
  2016年   25篇
  2015年   51篇
  2014年   62篇
  2013年   72篇
  2012年   114篇
  2011年   88篇
  2010年   83篇
  2009年   73篇
  2008年   103篇
  2007年   94篇
  2006年   85篇
  2005年   105篇
  2004年   77篇
  2003年   67篇
  2002年   79篇
  2001年   42篇
  2000年   39篇
  1999年   37篇
  1998年   39篇
  1997年   24篇
  1996年   25篇
  1995年   23篇
  1994年   23篇
  1993年   22篇
  1992年   25篇
  1991年   17篇
  1990年   21篇
  1989年   26篇
  1988年   24篇
  1987年   24篇
  1986年   27篇
  1985年   23篇
  1984年   10篇
  1983年   9篇
  1982年   10篇
  1980年   12篇
  1979年   10篇
  1977年   8篇
  1976年   8篇
  1975年   12篇
  1974年   9篇
  1973年   9篇
  1970年   10篇
排序方式: 共有1974条查询结果,搜索用时 142 毫秒
1.
Background and Aims: Primary biliary cirrhosis (PBC) might be complicated by osteoporosis, whose etiology remains unknown but seems to be multifactorial. Prevalence rates of 30% to 60% for distal renal tubular acidosis (DRTA) have been reported in PBC patients, generally as incomplete DRTA. Although it is undisputed that a reduced bone mineral density (BMD) is the expected outcome among patients who have been suffering from longstanding chronic metabolic acidosis, it is unclear if incomplete DRTA is also associated with metabolic bone disease in PBC patients. The present study was undertaken to compare the BMD of PBC patients with and without DRTA.
Methods: The BMD of 23 PBC patients (11 with DRTA and 12 without), all with normal clearance of creatinine, was assessed by dual energy radiograph absorptiometry. The diagnosis of DRTA was made if the urine pH was above 5.4 in all samples after the oral acid overload, showing tubular inability to acidify urine in the presence of test-induced systemic metabolic acidosis.
Results: Densitometric signs of osteoporosis were found in 82% of DRTA cases and in 83% of patients without DRTA (difference not significant). There were no significant differences in BMD measurement, T and Z scores of patients with and without DRTA.
Conclusions: The present study could not support a correlation between the presence of DRTA and the bone loss observed in PBC patients.  相似文献   
2.
3.
Twenty-three patients (16 adults) failing their first or subsequent (n = 8) intensive treatment for de novo acute lymphoblastic leukemia (ALL) and chronic myeloid leukemia lymphoid blast phase (n = 2) were managed with protocol POG 8201, originally introduced in relapsed ALL of childhood. In this programme, a four-drug induction phase is followed by early consolidation with teniposide-cytarabine, intrathecal chemotherapy, continuation weekly chemotherapy alternating teniposide-cytarabine with vincristine-cyclophosphamide, and periodic reinduction courses. Fourteen adults and five children with ALL achieved a complete response (CR) (86 per cent). The highest response rate (100 per cent) was obtained in 12 patients treated at first relapse after an initial CR of greater than 18 months (p = 0.07). Median duration of CR was 8 months in adults and 11 months in children. A longer than previous one CR (inversion) was obtained in four cases. Four ALL patients were successfully transplanted from a matched sibling after 3-11 months from achievement of CR. Median overall survival in adults with ALL was 11 months, significantly longer than for 40 comparable cases treated intensively but without rotational continuation therapy in previous years (p less than 0.001). This regimen is applicable to adults with relapsed ALL, where prolongation of survival may allow time for effective salvage with bone marrow transplantation.  相似文献   
4.
Measuring quality of life and assessing technologies are both increasingly prominent in health care systems. This growth has accompanied growing concern over aging populations and health care expenditure growth. Nevertheless, there appears to be unrealized potential for synergy between quality of life research and technology assessment. In this paper, we consider the roles and challenges facing quality of life research in three domains: research—particularly clinical trials of therapeutics; clinical situations and policy-making. We then examine the potential for synergy in these domains and conclude that expanding collaboration will strengthen both fields and intensity their impact in research, clinical practice and policy-making.Keynote address at the Second Meeting of the International Society for Quality of Life Research, Montreal, Quebec, Canada, 14–17 October 1995.  相似文献   
5.
We describe a patient with neonatal Marfan syndrome presenting with massive ascending and descending thoracic aortic aneurysm. Because of rapidly progressive respiratory distress due to tracheobronchial compression, emergency replacement of the descending thoracic aorta with a 12-mm PTFE vascular prosthesis was undertaken at 1 month of age. The postoperative course was complicated by bilateral tension pneumothorax contributing to irreversible respiratory failure. The unique clinico-pathological features and the relevant surgical implications of the case are discussed. (J Card Surg 1994;9:109–114)  相似文献   
6.
Summary— In the present study we have compared the steady state biopharmaceutic characteristics of four diltiazem once daily controlled release capsules: Mono-Tildiem LP 300® (300 mg), Adizem® XL (300 mg)1, Cardizem® (300 mg) and Dilacor® (240 mg). Sixteen healthy male volunteers (aged 22.9 ± 3.3 years, range 19–31 years) completed an open label, multiple oral dose, randomized, four-period crossover study without a washout period in between. The volunteers received each diltiazem formulation once daily for four days. Trough diltiazem and metabolites plasma concentrations were determined on days 3 and 4. The 24-h plasma concentration-time profiles were assessed after the dose on day 4 of each period. The following steady state pharmacokinetic parameters for diltiazem were calculated: the minimum plasma concentration (cmin), the maximum plasma concentration (cmax), the time to reach that concentration (tmax), the time interval during which the plasma concentration exceeds 50% of cmax (t50), the area under the plasma concentration-time curve (AUC72–96) and the peak-to-trough fluctuation (PTF). For the metabolites of diltiazem, N-mono-desmethyl-diltiazem (NDM) and desacetyldiltiazem (DAD), AUC72–96 (AUCNDM and AUCDAD) and the ratio metabolite/parent compound were calculated. Steady state was achieved on day 3. Except one, all controlled release formulations have satisfactory controlled release properties allowing once daily administration. However, significant (P < 0.05) differences were found between the pharmacokinetic characteristics which do not allow exchange of the various formulations. Concentrations well below 50 ng·mL-1 in the morning hours were observed for Dilacor® (240 mg) and Adizem® XL (300 mg), which could be a disadvantage of these formulations as it is well-known that ischaemic events occur at a higher rate during that part of the day. The plasma concentration profiles of NDM and DAD, the major circulating metabolites, parallel the plasma concentration profiles for the parent compound. From a clinical point of view, all treatments were well tolerated.  相似文献   
7.
8.
We conducted a study of general practitioners in Torino, Italy, to determine their patterns of preventive practice. We examined a set of primary and secondary preventive interventions and their determinants. We explored the determinants of primary preventive interventions (antismoking and alcohol abuse counseling, counseling for prevention of accidents at home among the elderly, flu vaccination for the elderly, and counseling on contraceptive use) and cancer early detection techniques (chest x rays and sputum cytology for lung cancer; mammography, physical examination, teaching of breast self-examination, and Papanicolaou [Pap] smear for gynecological cancers). Grouping determinants in cognitive, sociodemographic, and organization factors, we found different patterns for each maneuver. Cognitive factors played an important role, but their importance varied for each intervention. We found that smoking behavior of physicians predicted antismoking counseling. Further, the availability of other primary care services is an important factor in the early detection of gynecological cancers.  相似文献   
9.
PURPOSE: The purpose of this study was to identify the risk factors for severe discomfort after mandibular third molar surgery and to assess the validity of the Postoperative Symptom Severity (PoSSe) scale. PATIENTS AND METHODS: In a 2-year prospective study, a total of 255 unilateral impacted mandibular third molar teeth were surgically removed under local anesthesia by 3 surgeons. Standardized surgical and analgesic protocols were followed. At the review appointment, 1 week after surgery, all patients returned a completed follow-up questionnaire (PoSSe scale) and were evaluated clinically for postoperative pain (number of painkillers taken) and trismus (differences in mouth opening). Sixteen predictive variables were evaluated using stepwise logistic regression analysis to identify the risk factors associated with severe discomfort. RESULTS: Severe postoperative discomfort was predicted by these independent variables: gender, tobacco use, ramus relationship/space available, and antibiotic prophylaxis. Oral contraceptive use and operation time were not identified as risk factors. The patients' perceptions of the severity of symptoms (PoSSe scale score) was strongly correlated with clinical assessment of trismus (r = 0.54) and pain (r = 0.42). CONCLUSION: The PoSSe scale resulted in a valid and responsive measure of the severity of symptoms after surgical extraction of lower third molars and reflected the clinical severity of the postoperative discomfort. From a patient's perspective, operative factors had little bearing on the quality of life after removal of mandibular third molars.  相似文献   
10.
We developed a new cytomegalovirus (CMV) immunoglobulin M (IgM) immunoblot to detect CMV-specific IgM in human sera. The new test contains four viral proteins (vp150, vp82, vp65, and vp28) purified from viral particles and four recombinant proteins (rp150, rp130, rp52, and rp38) purified from Escherichia coli. These antigens were individually loaded onto nitrocellulose strips, and the strips were then used to detect CMV-specific IgM by using a μ-specific conjugate. The new assay was evaluated in parallel with one or two IgM enzyme-linked immunosorbent assays (ELISAs) to test 592 serum samples from different groups of latently or acutely infected individuals. The sensitivity of the new assay with respect to the consensus of two ELISAs was 100%, the specificity was 98.6%, the positive predictive value was 96.9%, and the negative predictive value was 100%. We also evaluated the new test by testing sera from pregnant women and transplant recipients with a known clinical history. Our results suggest that the new test combines high sensitivity with high specificity, characteristics that are mutually exclusive with the other commercially available tests. Furthermore, a statistically significant correlation was observed between the number of IgM-reactive bands and the elevated risk of transmission from CMV-infected pregnant women to their offspring.  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