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   238757篇
  免费   10243篇
  国内免费   622篇
耳鼻咽喉   3050篇
儿科学   7138篇
妇产科学   5954篇
基础医学   34099篇
口腔科学   7555篇
临床医学   15407篇
内科学   53328篇
皮肤病学   7162篇
神经病学   19643篇
特种医学   5899篇
外国民族医学   30篇
外科学   28360篇
综合类   1178篇
一般理论   45篇
预防医学   25786篇
眼科学   5634篇
药学   17735篇
中国医学   908篇
肿瘤学   10711篇
  2023年   1259篇
  2022年   1925篇
  2021年   4715篇
  2020年   2601篇
  2019年   4713篇
  2018年   6685篇
  2017年   4295篇
  2016年   4437篇
  2015年   4918篇
  2014年   6245篇
  2013年   9170篇
  2012年   14370篇
  2011年   15025篇
  2010年   8006篇
  2009年   6592篇
  2008年   12357篇
  2007年   13063篇
  2006年   12598篇
  2005年   12313篇
  2004年   11292篇
  2003年   10542篇
  2002年   10134篇
  2001年   6942篇
  2000年   7510篇
  1999年   6045篇
  1998年   1600篇
  1997年   1154篇
  1996年   1053篇
  1992年   3168篇
  1991年   2954篇
  1990年   2900篇
  1989年   2503篇
  1988年   2331篇
  1987年   2170篇
  1986年   2178篇
  1985年   2032篇
  1984年   1492篇
  1983年   1305篇
  1979年   1602篇
  1978年   1076篇
  1975年   1159篇
  1974年   1430篇
  1973年   1466篇
  1972年   1381篇
  1971年   1325篇
  1970年   1268篇
  1969年   1330篇
  1968年   1308篇
  1967年   1174篇
  1966年   1070篇
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
111.
OBJECTIVE: The authors tested the effect of blood sampling (skin versus venous puncture) on some biochemical and hematological blood parameters in athletes to answer whether skin puncture could be used as a substitute for venous puncture. DESIGN: Comparative study of 2 methods of blood samples collection. SETTING: The blood was collected in the same athletes at 3 different moments of the preparatory training phase. PARTICIPANTS: Fourteen male indoor soccer players (22 +/- 1 years old) and 7 female handball players (18 +/- 1 years old) participated. MAIN OUTCOME MEASUREMENT: Blood was collected in heparin and K3EDTA by Vacutainer BD or Microvette Sarstedt system for biochemical and hematological analyses, respectively. RESULTS: There were no significant statistical differences between the 2 methods for the values of creatine kinase, urea, creatinine, lymphocytes, and platelets. The other hematological analyzes and uric acid exhibited significant higher values in skin blood, although they were all within the normal expected range. A high degree of correlation was observed between the 2 techniques for all parameters. CONCLUSIONS: Skin puncture is a reliable, easy, accurate, and less invasive sampling method for assessing hematological and some biochemical parameters in athletes, respecting that blood samples should always be obtained from the same site, especially in follow-up studies.  相似文献   
112.
This study presents the case of a patient with necrobiosis or necrosing fascitis of the inguinal region, secondary to a complicated Amyand’s hernia with a concomitant ipsilateral Richter’s hernia. The patient was treated with open trans-abdominal surgery and hernia repair through the pre-peritoneal approach, plus anti-microbians, and thrice-daily wound cleansing and dressings to the inguinal region. Evolution was satisfactory. There are no reports in the literature of a case such as this.  相似文献   
113.
114.
J Czigány 《Orvosi hetilap》1989,130(4):177-181
The tele-thermographic examinations are of non-invasive character, they can be repeated any time and may be applied also for check-up examinations. The fact that they are evaluated together with other completing clinical examinations (X-ray, scintigraphy, ultrasonography, biopsy etc.) gives the objective significance and value of the examination. According to the author's observation the tele-thermography provides important help in the diagnostics of cervico-facial tumors, in the demonstration of metastases before the operation and detection of postoperative recurrences, in the follow-up of the patient's condition at the period of irradiation- or cytostatic therapy gives exact information in dermatology on the biological activity and extent of malignant melanoma. The treatment of persons with burn- or frostbite injuries requires it equally and good information may be obtained by its use on the condition of blood circulation in cases of vascular obstruction and vascular anomalies.  相似文献   
115.
116.
The purpose of this study is to determine the importance of two-dimensional echocardiography performed soon after admission to the coronary care unit to provide useful information concerning wall-motion abnormalities, and to detect and characterize left ventricular thrombi. A major goal is to identify a subgroup of patients with acute myocardial infarction who are at risk for systemic embolization; in this subgroup the benefits of anticoagulation treatment would theoretically outweigh the associated risks. We studied 7 consecutive male patients, age range from 32 to 60 years, with acute myocardial infarction. Five patients had antero-septal infarction, 1 anterolateral and another had anterior wall infarction. We performed two-dimensional echocardiography within the first week after admission. All patients had severe apical-wall-motion abnormalities (akinesis or dyskinesis) and left ventricular thrombi. All patients received anticoagulation therapy. Two-dimensional echocardiography, performed one month after the first study, showed that the thrombi had decreased in size in 6 patients and could not be visualized in 1 patient. The noninvasive nature of echocardiography allows serial evaluations of patients with known left ventricular thrombi and permits assessment of the effect of therapy.  相似文献   
117.
We present a case report of a patient suffering from portal and superior mesenteric vein thrombosis secondary to splenectomy. No surgical procedure could be performed due to the extension of thrombus.Local fibrinolysis treatment with urokinase through a percutaneous transhepatic approach was decided upon, and this procedure had a successful patient outcome.  相似文献   
118.
Evidence of the effect of exercise on bone loss comes mainly from studies in voluntary postmenopausal women, and no population-based, long-term interventions have been performed. The purpose of this population-based, randomized, controlled trial was to determine the effect of long-term impact exercise on bone mass at various skeletal sites in elderly women with low bone mineral density (BMD) at the radius and hip. Participants ( n =160) were randomly assigned to 30 months either of supervised and home-based impact exercise training or of no intervention. The primary outcome measures were femoral neck, trochanter and total hip BMD, and the secondary outcomes were bone density measures at the radius and calcaneum. Outcomes were assessed at baseline, 12 months and 30 months using blinded operators. The analyses were performed on an intention-to-treat analysis. Mean femoral neck and trochanter BMD decreased in the control group [–1.1%, 95% confidence interval (CI) –0.1% to –2.1% and –1.6%, 95% CI –0.4% to –2.7%], while no change occurred in the exercise group. Mean trochanter BMC decreased more in the control group (–7.7%, 95% CI –9.7% to –5.6% vs. –2.9%, 95% CI –5.3 to –0.9). There were six falls that resulted in fractures in the exercise group and 16 in the control group during the 30-month intervention ( P =0.019). A significant bone loss occurred in both groups at the radius and calcaneum. In multivariate analysis, weight gain was associated with increased BMD and BMC at all femur sites both in the exercise group and in the pooled groups. In conclusion, impact exercise had no effect on BMD, while there was a positive effect on BMC at the trochanter. Exercise may prevent fall-related fractures in elderly women with low bone mass.There was no conflict of interest.  相似文献   
119.
BACKGROUND: Artemisia species pollen represents a major cause of allergy in Central Europe. Variations in the pollen season, the influence of climate variables and the prevalence of pollinosis to it were analyzed in Poznan, in western Poland between 1995 and 2004. METHODS: A Hirst volumetric spore trap was used for atmospheric sampling. Pollination date trend analysis and Spearman correlation tests were performed. Skin prick tests (SPT) and allergen specific immunoglobulin (lg)E antibody measurements were performed in 676 and 524 patients, respectively. RESULTS: The Artemisia species pollen season grew longer due to a clear advance in the starting day and only a slightly earlier end point; the peak day also came slightly earlier. Rainfall in the first fortnight of July highly influenced pollen season severity. Temperature was directly correlated with daily Artemisia species pollen levels; relative humidity was inversely correlated. Twelve percent of patients had a positive SPT reaction to Artemisia species. Their symptoms were rhinitis and conjunctivitis (15%), atopic dermatitis (15%), chronic urticaria (14.3%), bronchial asthma (2.4%), and facial and disseminated dermatitis (1.3%). Elevated specific IgE concentrations were detected in the sera of 10.1% of patients. CONCLUSIONS: Artemisia species pollen is an important cause of pollinosis in western Poland. Pollen season intensity is highly influenced by rainfall in the previous weeks. Trends towards earlier season starts and longer duration, possibly caused by climate change, may have an impact on the allergic population.  相似文献   
120.
PTH fragments consisting of the C-terminal portion of the molecule may have biologic effects and may modify the actions of PTH. Evidence for the presence of a C-terminal PTH receptor further supports a biologic role for such fragments. Because C-PTH fragments accumulate in patients with renal insufficiency, it is possible that they may contribute to renal bone disease. The precise role of circulating C-PTH fragments in the pathogenesis, diagnosis, and management of renal osteodystrophy, however, remains to be determined. Future studies of the biologic effects and regulation of these fragments may lead to better understanding of skeletal biology and may also improve our approach to the diagnosis and treatment of renal bone disease.  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