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   13922篇
  免费   1026篇
  国内免费   68篇
耳鼻咽喉   106篇
儿科学   397篇
妇产科学   228篇
基础医学   2388篇
口腔科学   314篇
临床医学   1258篇
内科学   3112篇
皮肤病学   312篇
神经病学   1663篇
特种医学   284篇
外科学   1329篇
综合类   60篇
一般理论   9篇
预防医学   1057篇
眼科学   146篇
药学   1183篇
中国医学   49篇
肿瘤学   1121篇
  2024年   19篇
  2023年   132篇
  2022年   327篇
  2021年   627篇
  2020年   345篇
  2019年   440篇
  2018年   498篇
  2017年   392篇
  2016年   443篇
  2015年   471篇
  2014年   573篇
  2013年   705篇
  2012年   1095篇
  2011年   1170篇
  2010年   661篇
  2009年   538篇
  2008年   846篇
  2007年   884篇
  2006年   770篇
  2005年   755篇
  2004年   719篇
  2003年   592篇
  2002年   567篇
  2001年   100篇
  2000年   83篇
  1999年   92篇
  1998年   116篇
  1997年   114篇
  1996年   68篇
  1995年   72篇
  1994年   53篇
  1993年   43篇
  1992年   44篇
  1991年   66篇
  1990年   64篇
  1989年   51篇
  1988年   45篇
  1987年   30篇
  1986年   43篇
  1985年   39篇
  1984年   29篇
  1983年   22篇
  1982年   21篇
  1981年   22篇
  1979年   22篇
  1978年   24篇
  1976年   15篇
  1975年   20篇
  1971年   16篇
  1968年   16篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Exercise-induced changes in the activity of serum lactate dehydrogenase (LDG) and its isoenzymes, CK, aspartate and alanine aminotransferase, were examined in postmyocardial-infarction coronary patients with second-type diabetes mellitus and 18 chronic coronary patients with second-type diabetes mellitus. Patients from both groups showed increased total LDG and LDG-5 activity at rest and reduced total LDG, LDG-1, LDG-2 and LDG-3 activity in response to exercise, which may be an evidence of prevailing anaerobic glycolysis as a manifestation of tissue hypoxia. Rationed bicycle ergometric exercise produces no rise in blood CK, aspartate and alanine aminotransferase activities in coronary patients with second-type diabetes mellitus, suggesting that exercise of this kind has no damaging effect on myocardial and skeletal-muscle myocytes.  相似文献   
32.
The clinical and electrophysiological features of a truncal myoclonus in a 55-year-old man are described. The electromyographic characteristics point toward propriospinal myoclonus. It is suggested that a myoclonic generator was released after use of ciprofloxacin, by antagonising the gamma-aminobutyric acid metabolism.  相似文献   
33.
The results of the first 3 year' collaboration of the Italian Registry of Paediatric Chronic Peritoneal Dialysis (CPD) (1986–1988) are presented. This Registry acquired data on the majority of the paediatric patients treated with CPD in Italy, thus providing a national picture in a field where few nationwide surveys are available. Patients of less than 15 years of age at the start of dialysis were enrolled and clinical data collected until the age of 19 years. The number of nephrological paediatric centres participating in the Registry increased from 7 in 1986 to 11 in 1988. The total number of patients on CPD was 70 and the percentage of dialysed children treated with CPD ranged from 40.2% to 43.6%. Data on 89 peritoneal catheters were collected: during 1417 dialysis-months 70 catheter-related complications were observed (1:20.8 dialysis-months); actuarial catheter survival was 92.7% at 6 months, 84.8% at 1 year and 68.8% at 2 years. The incidence of peritonitis changed from 1 episode every 10.9 patient-months in 1986 to 1 every 19.8 in 1988. Abdominal hernias were the other main clinical complication observed. The survival of patients was 92.5% at 3 years, while the technique survival at the same time was 84%.  相似文献   
34.
Endothelin-1 in children with chronic renal failure   总被引:1,自引:0,他引:1  
Endothelin-1 (ET-1) was meansured after extraction from plasma of normal adults (5.9±1.9 pg/ml,n=22), normal children (7.1±1.86 pg/ml,n=29), nonhaemodialysed children with chronic renal failure (CRF) (11.1±1.8 pg/ml),n=10), renal graft recipients (9.5±3.4 pg/ml,n=37), haemodialysed children 24 h after a haemodialysis session (20.02±10.9 pg/ml,n=26) and haemodialysed children before and after a haemodialysis session (15.31±10.6 and 13.8±8.5 respectively,n=14). A sensitive and specific radioimmunoassay was used. ET-1 was significantly higher in non-haemodialysed CRF children and in renal graft recipients than in normal children (P<0.001 andP<0.01, respectively) and significantly higher in haemodialysed children when compared with normal children, non-haemodialysed CRF children and renal graft recipients (P<0.001). ET-1 concentrations were similar in normal children and normal adults. ET-1 was inversely correlated with glomerular filtration rate in non-haemodialysed CRF children (r=–0.39,P<0.01) and positively correlated with extracellular volume in haemodialysed children (r=0.435,P<0.03). After haemodialysis, ET-1 increased in 6 and decreased in 8 of the 14 children studied before and after a haemodialysis session.  相似文献   
35.
The optimum extraction conditions for obtaining a new mixed plant preparation (tanton) have been determined and its phytochemical composition has been studied. The antistressor activity of tanton has been established in experiments on white rats. __________ Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 41, No. 11, pp. 42–46, November, 2007.  相似文献   
36.
Leiomyosarcoma of the oral cavity is a very rare tumor associated with aggressive clinical behavior and low survival. In this paper, we report 2 cases of leiomyosarcoma, affecting the gingival mucosa of a 54-year-old female and the maxillary bone of a 63-year-old male. Histologically, the tumors were composed of variably oriented fascicles of spindle-shaped cells with cigar-shaped nuclei and eosinophilic cytoplasm. The lesions were treated by surgical resection. Immunoreactivity to anti-vimentin, anti-smooth muscle actin, anti-desmin, anti-laminin, and anti-muscle-specific actin antibodies were found; conversely, the tumor cells were negative for anti-S100 and AE1/AE3 proteins. This report emphasizes the role of immunohistochemical study for correct diagnosis of leiomyosarcoma.  相似文献   
37.
The majority of foot and ankle operations are performed on an outpatient basis and often under some form of regional anesthesia. In this prospective, randomized study of 51 patients undergoing elective unilateral forefoot procedures, we compared 2 different anesthetic techniques: the peripheral foot blockade and the popliteal sciatic nerve block. Variables assessed included the quality of surgical anesthesia, postoperative analgesia, and the incidence of postoperative complications. The anesthesia was classified as effective if it was the sole anesthetic technique for the forefoot surgery. We found successful results in both groups: 92% in the foot block group and 96% in the popliteal block group. Analysis of time required to perform the anesthetic procedure showed a significant difference between the 2 groups, with foot block being considerably faster (14.3 minutes vs 19.2 minutes for popliteal block) (P = .0078). Foot block patients demonstrated 10.96 hours of analgesia, whereas popliteal block patients exhibited 14.32 hours (P = .132). With a mean follow-up of 5.7 months, we did not find anesthesia-related complications in any of the patients. Both techniques showed a high level of safety and efficacy, with no significant difference detected between them. Our patients showed a high rate of satisfaction with both procedures (96% for foot block patients and 96.1% for popliteal block patients) and reported a good discharge disposition. These data show that both procedures are safe and effective anesthetic techniques and well suited to forefoot ambulatory surgery.  相似文献   
38.
BACKGROUND/PURPOSE: If the occlusion time of a closed chamber evaporimeter on the skin is too long, saturation might occur. We previously compared an open chamber and a closed chamber device on healthy volunteers. Comparable data on stripped skin with higher evaporation rates are not available. This study compares the sensitivity and correlation of open and closed chamber devices in a tape-stripping human model. The amount of tape removed SC was also quantified with a protein assay method. METHODS: Ten healthy volunteers (six male and four female; seven Caucasians and three Asian; mean age 38+/-16) were enrolled. In a randomized manner, one forearm was measured by an open chamber device and the opposite by a closed chamber device. After recording baseline measurements, 20 strippings were taken on each test site with tape disks. Transepidermal water loss (TEWL) was measured at the end of 10 and 20 tape strippings at each test site. Stratum corneum (SC) aggregates in the strips was assayed. RESULTS: The mean values obtained from two devices were similar after 10 trips and 20 strips. There was no statistically significant difference. The closed chamber device showed a slightly higher (but not significant) inter-individual coefficient of variation. SC aggregates in the strips were similar and without a statistically significant difference. CONCLUSION: The study suggests that both devices might yield similar TEWL values on stripped human skin in vivo.  相似文献   
39.
40.
Atherosclerotic cardiovascular disease is the most common cause of death in the United States. Investigation of atherosclerotic plaque morphology and composition is important because the findings may be useful in predicting prognosis or response to therapy. This study presents high-resolution magnetic resonance (MR) imaging techniques developed on a 1.5-T whole-body imager with a custom-built surface coil, for characterizing the composition and morphology of plaque removed at carotid endarterectomy. The initial comparison of MR imaging and histologic results showed good correlation. In conjunction with MR angiography, these techniques could be used in in vivo imaging to define the size, location, and contents of atherosclerotic plaque at the carotid bifurcation.  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