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   1607篇
  免费   72篇
  国内免费   11篇
耳鼻咽喉   72篇
儿科学   29篇
妇产科学   17篇
基础医学   227篇
口腔科学   23篇
临床医学   115篇
内科学   395篇
皮肤病学   8篇
神经病学   86篇
特种医学   77篇
外科学   263篇
综合类   8篇
预防医学   33篇
眼科学   29篇
药学   107篇
中国医学   7篇
肿瘤学   194篇
  2023年   7篇
  2022年   13篇
  2021年   29篇
  2020年   18篇
  2019年   28篇
  2018年   28篇
  2017年   21篇
  2016年   29篇
  2015年   36篇
  2014年   46篇
  2013年   54篇
  2012年   109篇
  2011年   124篇
  2010年   60篇
  2009年   46篇
  2008年   89篇
  2007年   96篇
  2006年   97篇
  2005年   75篇
  2004年   107篇
  2003年   121篇
  2002年   89篇
  2001年   26篇
  2000年   21篇
  1999年   24篇
  1998年   36篇
  1997年   20篇
  1996年   27篇
  1995年   17篇
  1994年   11篇
  1993年   12篇
  1992年   27篇
  1991年   18篇
  1990年   21篇
  1989年   10篇
  1988年   14篇
  1987年   16篇
  1986年   8篇
  1985年   5篇
  1984年   8篇
  1983年   3篇
  1982年   4篇
  1981年   9篇
  1980年   5篇
  1979年   5篇
  1976年   3篇
  1975年   3篇
  1968年   3篇
  1967年   2篇
  1966年   2篇
排序方式: 共有1690条查询结果,搜索用时 15 毫秒
41.
OBJECTIVE: Serum hepatocyte growth factor (HGF) is associated with blood pressure. We investigated whether the serum HGF level differs between hypertensive and normotensive postmenopausal women (PMW) and whether hormone replacement therapy (HRT) alters the serum HGF level and blood pressure in hypertensive and normotensive PMW. DESIGN: Prospective observational study. METHODS: A total of 33 PMW with mild to moderate essential hypertension controlled by antihypertensive treatment (mean age, 57 +/- 6 years) and 23 normotensive PMW (mean age, 57 +/- 7 years) received continuous HRT (0.625 mg of conjugated equine estrogen combined with 2.5 mg of medroxyprogesterone acetate) once a day orally for 12 months, and we measured serum HGF levels and blood pressure before and 12 months after the start of HRT. RESULTS: The baseline serum HGF level was significantly higher in hypertensive PMW than in normotensive PMW. HRT significantly decreased the serum HGF level in hypertensive subjects, from 2.85 +/- 0.64 pmol/l to 2.49 +/- 0.65 pmol/l (P < 0.001), but not in normotensive subjects. HRT did not change blood pressure in either group. CONCLUSIONS: Serum HGF level before the start of HRT was higher in the hypertensive PMW than in the normotensive PMW. Furthermore, HRT decreases serum HGF without decreasing blood pressure in hypertensive PMW. The HRT-induced decrease in serum HGF was greater in hypertensive PMW than in normotensive PMW, and the decrease was independent of blood pressure changes.  相似文献   
42.
A 28-day in vivo treatment trial to evaluate the efficacy of pyrimethamine/sulfadoxine (Fansidar, PS) was conducted in 21 Lao patients with uncomplicated Plasmodium falciparum malaria. Sixteen patients (76%) were completely cured with PS without any reappearance of asexual stage parasitemia during the follow-up examination. On the other hand, 5 patients (24%) failed to respond to this trial medication, resulting in recrudescence of asexual stage P. falciparum malaria. PS resistance resulted in higher prevalence of post-treatment gametocytemia, 25% gametocyte carriers among PS sensitive cases versus 75% of the resistant cases. These findings suggest that although the level of PS resistance is still valid for treatment of malaria in the study area of Lao PDR, post-treatment induction of gametocytemia among resistant cases may result an increase in transmission rate of PS resistant falciparum malaria.  相似文献   
43.
Measles virus was isolated from the middle ear fluid (MEF) of two infant cases of acute otitis media (AOM) associated with measles. This is the first report on the isolation of measles virus from the MEF in patients with AOM, and possibility of the measles virus as a causative agent of AOM was suggested.  相似文献   
44.
Chronic thromboembolic pulmonary hypertension (CTEPH) has a poor prognosis because of the associated progressive right heart failure. Accurate evaluation of right ventricular (RV) function would thus be useful to predict prognosis. However, the significance of RV diastolic function remains unclear. We aimed to identify which echocardiographic measures are most accurate, and potentially useful, in assessing RV diastolic function in patients with CTEPH, and to study the effects of balloon pulmonary angioplasty (BPA) on them. We enrolled 53 CTEPH patients who underwent BPA. Echocardiographic parameters, including two-dimensional speckle-tracking echocardiography, were compared to the hemodynamic parameters measured by right heart catheterization before and after BPA. RV strain rate during early diastole (SR_E), tricuspid e′ and right atrial area (RAA) were ameliorated after BPA, concomitant with a decrease in the time constant of the RV pressure curve during diastole (tau), indicating the improvement of RV diastolic function. Among them, SR_E had the strongest correlation with tau (r?=???0.39, p?<?0.001). Furthermore, the receiver operating characteristic analyses revealed that E/SR_E (AUC 0.704) and inferior vena cava diameter (AUC 0.726) had a stronger association with higher mean right atrial pressure than RAA (AUC 0.632). In contrast, RAA had a stronger correlation with 6 min-walk distances than SR_E (r?=???0.39, p?<?0.001 vs. r?=?0.30, p?=?0.005). Taken together, echocardiographic assessment of RV diastolic function might be associated with hemodynamics as well as exercise tolerance in patients with CTEPH, indicating its benefits in evaluating the therapeutic effects of BPA.  相似文献   
45.
We describe a gastric carcinoma cell line that has been maintained in vitro for more than 10 years and retains the capacity to produce a large amount of alpha-fetoprotein. This cell line was isolated from a metastatic lymph node of a 63-year-old male patient with advanced gastric carcinoma (T2N3P0H0M0) who showed high serum levels of alpha-fetoprotein. The primary tumor was moderately differentiated tubular adenocarcinoma and the lymph node was poorly differentiated adenocarcinoma without any particular pattern. The cultured cells grew as densely packed islet-like colonies with small polygonal cells. Electron microscopy revealed cells abundant in cytoplasmic organelles, with some cellular attachments being tight with junctional complexes and some being loose across intercellular spaces. The free cell surface had microvilli. The population doubling-time was 152 h at passage 58. Chromosomal analysis revealed the modal number to be 77, with numerous karyotype abnormalities. The tumorigenicity of the cultured cells in athymic nude mice was positive only when they were subcutaneously transplanted beneath a plastic plate, but when the cells were transplanted subcutaneously or administered by intrasplenic injection in intact or weakly irradiated nude mice, no tumorigenicty was shown. The cell line produced tumor-associated antigens, such as alpha-fetoprotein, carcinoembryonic antigen, and tissue polypeptide antigen. This cell line may be useful for comparative studies of different types of gastric carcinoma and alpha-fetoproteins of different origins.  相似文献   
46.
Background and objective:   Patient satisfaction with health care has increasingly been recognized as an important health outcome, but few studies have examined patient satisfaction with flexible bronchoscopy (FB). The purpose of this study was to assess patient satisfaction with FB conducted under conscious sedation and to identify the aspects of the procedure related to patient satisfaction.
Methods:   Patients' willingness to return for repeat FB was measured on a 5-point scale. Patients were asked whether they were bothered by the anaesthetic spray, scope insertion, shortness of breath, coughing, pharyngeal pain, chest pain or swallowing pain. Patients were asked to assess the quality of the physician, the institution and nursing, and their satisfaction with the privacy, waiting time and information provided about the procedure.
Results:   Of 161 consecutive eligible patients who underwent FB, 129 (80.1%) completed the questionnaire. Of the 129 patients, 65.8% reported that they would return for a repeat FB (12.4% would definitely return and 53.4% would probably return). Male gender, shorter examination time, excellent physician quality and not being bothered by coughing, pharyngeal pain or swallowing pain were related to greater patient satisfaction. The results of multiple logistic regression analysis showed that male gender was related to greater patient satisfaction.
Conclusions:   Bronchoscopists should try to recognize the factors that influence patient satisfaction and adjust their management accordingly.  相似文献   
47.
Perlman syndrome is a rare, autosomal recessive overgrowth disorder. Recently, the deletion of exon 9 and other mutations of the DIS3L2 gene have been reported in patients; however, the mechanism behind this deletion is still unknown. We report the homozygous deletion of exon 9 of DIS3L2 in a Japanese patient with Perlman syndrome. We identified the deletion junction, and implicate a non-allelic homologous recombination (NAHR) between two LINE-1 (L1) elements as the causative mechanism. Furthermore, the deletion junctions were different between the paternal and maternal mutant alleles, suggesting the occurrence of two independent NAHR events in the ancestors of each parent. The data suggest that the region around exon 9 might be a hot spot of L1-mediated NAHR.  相似文献   
48.
49.
OBJECTIVE: To investigate the involvement of osteopontin (OPN) in bone destruction in a murine experimental arthritis model of collagen-induced arthritis (CIA). METHODS: The expression of OPN was examined at both the messenger RNA (mRNA) and protein levels in various arthritic lesions in mice with CIA by in situ hybridization and immunohistochemistry, respectively. In addition, the expression of alpha(v)beta3 integrin, a receptor for OPN, the ligation of which is thought to be essential for bone resorption by osteoclasts, was examined by immunohistochemistry. Plasma concentrations of OPN were measured at different time points in the course of CIA by enzyme-linked immunosorbent assay. RESULTS: OPN mRNA was detected mainly at sites of bone erosion in arthritic lesions, where activated osteoclasts were present; OPN protein was also detected at sites of bone erosion. In the arthritic synovium, OPN was predominantly expressed in the synovial lining layer, but not in lymphoid aggregates. In addition, alpha(v)beta3 integrin was detected coincident with OPN at sites of bone erosion (bone-pannus junction). Plasma OPN levels were markedly elevated at the time points that corresponded to arthritis flares, and higher levels were maintained during the progression of arthritis. CONCLUSION: OPN may mediate bone resorption by osteoclasts in arthritis through ligation with its receptor, alpha(v)beta3 integrin. OPN may be a useful therapeutic target molecule in the prevention of bone destruction in arthritis.  相似文献   
50.
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