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   16890篇
  免费   1069篇
  国内免费   57篇
耳鼻咽喉   233篇
儿科学   388篇
妇产科学   401篇
基础医学   2181篇
口腔科学   1095篇
临床医学   1285篇
内科学   3684篇
皮肤病学   389篇
神经病学   1319篇
特种医学   477篇
外国民族医学   1篇
外科学   1929篇
综合类   145篇
一般理论   6篇
预防医学   1661篇
眼科学   278篇
药学   1523篇
中国医学   121篇
肿瘤学   900篇
  2023年   111篇
  2022年   308篇
  2021年   542篇
  2020年   341篇
  2019年   448篇
  2018年   550篇
  2017年   414篇
  2016年   442篇
  2015年   521篇
  2014年   637篇
  2013年   870篇
  2012年   1116篇
  2011年   1174篇
  2010年   694篇
  2009年   602篇
  2008年   912篇
  2007年   895篇
  2006年   799篇
  2005年   736篇
  2004年   626篇
  2003年   584篇
  2002年   507篇
  2001年   422篇
  2000年   398篇
  1999年   316篇
  1998年   160篇
  1997年   138篇
  1996年   123篇
  1995年   100篇
  1994年   100篇
  1993年   94篇
  1992年   221篇
  1991年   195篇
  1990年   192篇
  1989年   169篇
  1988年   154篇
  1987年   116篇
  1986年   133篇
  1985年   112篇
  1984年   85篇
  1983年   74篇
  1982年   70篇
  1981年   53篇
  1980年   59篇
  1979年   95篇
  1978年   51篇
  1977年   64篇
  1976年   49篇
  1975年   56篇
  1974年   48篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Pregnancy is a major factor that modifies psychosocial aspects of the adolescents. A study with 120 pregnant adolescents aged 12 to 18 years, without regarding gestational age, was carried out at Prenatal Risk Program in the Secretaria Estadual de Saúde, Belém-Pará, from 10/1991 to 04/1992. At the first encounter, it was made an approach of psychosocial and sexual subjects, with the following results: onset of menarche primarily between 12-13 years old (median 12.2 years old); beginning of sexual practice at 14 years old in 50.9% of the adolescents. 56.6% were pregnant at 16 years old. Most of the adolescents (98.4%) first had sexual intercourse with their boy friends and by their own wish (72.5%). In one year of loving affair, 67.5% of the adolescents have already begun sexual activities, this attitude more prevalent among the younger(79.4%). Adolescents had learned about sexuality mainly from mates (65.1%). Although 55.9% of the adolescents were aware of some contraceptive method, just 13.3% of them used one. The majority of the pregnant adolescents (96.7%) were financially supported by their families. Respectively, 30.3% and 32.1% of these girls left school before or during pregnancy. The risk factors that may contribute to an early and unintended pregnancy among adolescents, specially the younger ones, were pointed out: little information about sex and contraceptive methods, limited practice on their use and a high rate of precocious sexual activities.  相似文献   
92.
This paper examines the peculiarities of the expression of emotion in a poor neighborhood from Northeastern Brazil, the bairro of Nordeste de Amaralina, in Salvador, Bahia. Focusing on the expression of sadness, we built a scheme in which to understand how the informants perceive, identify, and deal with this emotion in the course of their daily lives. We attempted to reach an understanding of the wavs people in the bairro interpret sadness. In order to accomplish this goal. we built a semantic network which revealed three main clusters of emotional expression: the inner set, the bodily set, and the interactional set. We came to realize the various superpositions benween the universe of emotional expression and the local concept of person.  相似文献   
93.
94.
95.
This study deals with adherence to tuberculosis treatment among men and women as well as the disease's links and consequences vis-à-vis life styles and treatment outcomes. The ethnographic study was a component of the Tuberculosis Epidemiological Control Project in the city of Pelotas and aimed to identify the reasons patients failed to complete treatment. Direct ethnographic observations and semi-structured interviews were used. Use of the term "adherence" is justified by the concern for extending to other fundamental factors in addition to the patient's own individual responsibility. This approach fostered an understanding of views towards disease, social dynamics among the various protagonists involved in the disease process, and treatment. Some of the factors considered in adherence to treatment were: socio-demographic characteristics, cultural factors, popular beliefs, the cost-benefit relationship, physical and chemical aspects of the drugs, the physician-patient relationship, and level of family participation in treatment.  相似文献   
96.
碱离子水饮用后血小板聚集率的的变化(附30例报告)   总被引:1,自引:0,他引:1  
目的:报告30例饮用豪斯牌碱离子水前、后血小板聚集率的变化。方法:饮用碱离子水前、后(2~3月,>3~6月)作比浊法血小板聚集试验,以1分钟、5分钟及5分钟内最大聚集率(Max%)为指标,同时检测部分血粘度指标及凝血因子,并用自动生化仪检测血糖、血脂、主要电解质及部分肝、肾功能。结果:饮碱离子水后,血小板聚集率明显下降,而以疾病组(Max>80%)下降尤为明显,P均<0.001。饮碱离子水后血小板聚集率的下降,部分可能与损伤的血管内皮得到修复有关。主要电解质及部分肝、肾功能无明显异常改变。结论:由于心、脑血管血栓性疾病患者血小板聚集率多明显升高,饮碱离子水后血小板聚集率明显下降,且长期饮用对主要电解质及部分肝、肾功能无明显异常改变,作者认为碱离子水使用方例、安全、有效、价廉,因而对心、脑血管血栓性疾病防治方面可能是一种积极的辅助方法,值得临床进一步探索。  相似文献   
97.
Preimplantation retrograde pneumoplegia in clinical lung transplantation.   总被引:6,自引:0,他引:6  
OBJECTIVE: Retrograde pneumoplegia seems to improve early graft function in experimental and clinical lung transplantation. We evaluated the role of retrograde flushing in addition to antegrade pneumoplegia in clinical lung transplantation. METHODS: Fourteen patients undergoing lung transplantation were randomized into 2 groups: in group I we performed antegrade pulmonary artery flushing with alprostadil (prostaglandin E1) and modified Euro-Collins solution at the time of retrieval. In group II additional retrograde flushing through the pulmonary veins was performed at the back table, before reimplantation. Hemodynamic variables, mean airway pressure, and blood gas analysis were monitored at different time points. Postoperative volumetric monitoring was performed to assess extravascular lung water. The reimplantation response was assessed by a radiographic score; extubation time and intensive care unit stay were recorded. RESULTS: During retrograde flushing, blood and clots coming out from the pulmonary artery were observed; 2 lungs harvested from a donor with multiple bone fractures had fat emboli in the retrograde perfusate. Hemodynamic monitoring did not demonstrate any difference between the 2 groups. The ratio of arterial oxygen tension to inspired oxygen fraction, extravascular lung water, duration of intubation, and length of stay in the intensive care unit were improved in group II, but the differences did not reach statistical significance. Intrapulmonary shunt fraction was significantly improved in group II at each time point ( P =.02), as well as indexed alveolar-arterial oxygen tension gradient (P =.04), mean airway pressure (P =.04), and chest x-ray score ( P =.03). CONCLUSIONS: Preimplantation retrograde flushing is not detrimental and helps to improve early graft function.  相似文献   
98.
OBJECTIVE: To evaluate the safety and efficacy of holmium:YAG laser vaporization v transurethral electroresection (TURP) for benign prostatic hyperplasia. PATIENTS AND METHODS: Thirty-six patients were randomized. Two laser procedures (60 to 80 W) were performed for one TURP. Symptom Score, peak flow rate, potency, and ejaculation status were measured at baseline and at 1, 3, 6, and 12 months. RESULTS: The mean operative time was 75 minutes for laser and 56 minutes for TURP (P = 0.0407). With a mean laser energy delivered of 103.6 kJ, hemostasis was satisfactory during vaporization. The mean catheterization time was 1.7 and 2.1 days in the laser and TURP group, respectively. For the laser and TURP groups, the mean AUA Score improved from 20 preoperatively to 7 and from 24.1 to 5, respectively, at 12 months. The mean peak flow increased from 8.4 to 19.5 mL/sec and from 7.6 to 16.8 ml/sec, respectively, at 12 months. These results are not statistically different. No significant initial dysuria occurred. No significant difference between the groups appeared in potency or ejaculatory status during the follow-up. One patient in the laser group (Day 5) and two in the TURP group (2nd and 6th month) had to undergo a second procedure to relieve obstruction. CONCLUSION: Although taking slightly longer to accomplish, holmium:YAG laser vaporization of BPH provides early results very similar to those of TURP with a shorter catheterization time and no initial dysuria or pain.  相似文献   
99.
OBJECTIVES: Struvite calculus formation requires an alkaline urinary pH. An acidic urinary pH will dissolve struvite calculi and prevent recurrent struvite stone formation. Long-term urinary acidification has been unsuccessful. We sought to determine whether a gastric patch (with viable parietal cells) anastomosed to the renal pelvis could create an acidic urinary milieu. METHODS: A vascularized stomach patch (from the greater curvature) was anastomosed to the left renal pelvis in 15 female pigs. The right kidney was used as a control. The first 6 pigs were used to refine the surgical technique. The remaining 9 pigs were subjected to a formal gastropyeloplasty and followed up for 4 weeks. Urine was collected before and after stimulation with pentagastrin. Urine pH was measured from both kidneys in response to gastrin stimulation and oral intake. The kidneys, ureters, and bladders were examined for gross changes and histologic review. RESULTS: The 9 test animals had more acidic urine in the control kidney than in the gastropyeloplasty kidney. Pentagastrin had no significant impact on urinary pH. Hydroureteronephrosis and a concentrating defect were noted in the treated kidney. Histologic review revealed smooth muscle hyperplasia of the left ureter and viable parietal cells in the stomach patch. CONCLUSIONS: An animal model was developed to transfer a gastric patch to the renal pelvis. Hydronephrosis and ureteral dilation were associated with this gastric patch. We were unable to acidify the urine despite viable parietal cells in the transposed stomach segment. Further refinements of this concept may be successful in acidifying urine in the hope of preventing recurrent struvite nephrolithiasis.  相似文献   
100.
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