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   1580624篇
  免费   111842篇
  国内免费   4843篇
耳鼻咽喉   19987篇
儿科学   51024篇
妇产科学   41959篇
基础医学   232737篇
口腔科学   42275篇
临床医学   149148篇
内科学   312152篇
皮肤病学   33386篇
神经病学   133968篇
特种医学   55154篇
外国民族医学   471篇
外科学   214615篇
综合类   29884篇
现状与发展   1篇
一般理论   533篇
预防医学   136703篇
眼科学   33575篇
药学   116079篇
  6篇
中国医学   3930篇
肿瘤学   89722篇
  2021年   15726篇
  2019年   16520篇
  2018年   24000篇
  2017年   17325篇
  2016年   18337篇
  2015年   20844篇
  2014年   27542篇
  2013年   42293篇
  2012年   61078篇
  2011年   63888篇
  2010年   35838篇
  2009年   32200篇
  2008年   56942篇
  2007年   60201篇
  2006年   59248篇
  2005年   57628篇
  2004年   54523篇
  2003年   51495篇
  2002年   49588篇
  2001年   66406篇
  2000年   68081篇
  1999年   57259篇
  1998年   15983篇
  1997年   14372篇
  1996年   14083篇
  1995年   13347篇
  1994年   12392篇
  1993年   11614篇
  1992年   44387篇
  1991年   43388篇
  1990年   41913篇
  1989年   39611篇
  1988年   36676篇
  1987年   35694篇
  1986年   34010篇
  1985年   32352篇
  1984年   24310篇
  1983年   20694篇
  1982年   12401篇
  1979年   21926篇
  1978年   15598篇
  1977年   12793篇
  1976年   12510篇
  1975年   12892篇
  1974年   15748篇
  1973年   15422篇
  1972年   14268篇
  1971年   13341篇
  1970年   12344篇
  1969年   11280篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Familial 46,XX gonadal dysgenesis   总被引:1,自引:0,他引:1  
Two sisters, ages 18 and 25, presented with primary amenorrhea and underwent clinical, hormonal, cytogenetic, and pathologic evaluation. Both were of normal stature and lacking of somatic stigmata. Both patients had normal 46,XX karyotype on peripheral blood. Streak gonads were seen in both patients and a rather scanty number of primordial follicles was found in one patient. FSH, LH, and urinary estrogens were consistent with streak gonad syndrome. Autosomal recessive inheritance has been suggested in familial aggregates with XX gonadal dysgenesis.  相似文献   
992.
Cardiocyclide, a new Russian class III antiarrhythmic agent, was developed at the State V. V. Zakusov Science Research Institute Pharmacology, Russian Academy of Medical Sciences. The aims of the present work were to study the physicochemical properties of the hydrochloride salt of this agent (N1-(3-diethylaminopropyl)-N1-(p-nitrobenzoyl)aminoacetic acid N,N-dicyclohexylamide HCl) and to develop an analytical method for this compound. IR, 1H NMR, and UV spectra were obtained for cardiocyclide; its solubility was studied; its melting temperature, weight loss on drying and the transparency, color, and pH of its solutions were determined. The purity of material containing compound I was determined by thin-layer chromatography; quantitative cardiocyclide contents were estimated by non-aqueous titration. __________ Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 41, No. 8, pp. 42–45, August, 2007.  相似文献   
993.
994.
The substitution of leucine for valine at amino acid position 34 of the factor XIII gene is commonly referred to as FXIII Val34Leu polymorphism. The homozygous leucine/leucine genotype has been reported to confer protection against venous thromboembolism, but previous studies have not evaluated a population limited to those with idiopathic venous thromboembolism. The primary objective of the study was to determine whether the FXIII Val34Leu polymorphism is independently associated with the occurrence of idiopathic venous thromboembolism. We prospectively enrolled consecutive patients with at least one objectively confirmed idiopathic venous thromboembolism. Friends of cases were recruited as controls and matched to cases by sex, ethnicity, and age. All participants were tested for the FXIII Val34Leu polymorphism in addition to several well-known thrombophilias. Data from 309 cases and 306 controls were analyzed. The FXIII leucine/leucine genotype was present in 4.9% of cases and 6.5% of controls. An adjusted odds ratio of 0.59 (95% confidence interval, 0.25-1.38) was found for the recessive model and 0.69 (95% confidence interval, 0.46-1.02) for the dominant model. Our results do not support an independent association of the FXIII Val34Leu polymorphism with idiopathic venous thromboembolism in our Caucasian Canadian study population.  相似文献   
995.
Background: Bupivacaine retards myocardial acidosis during ischemia. The authors measured function of rat isolated hearts after prolonged storage to determine whether bupivacaine improves cardiac protection compared with standard cardioplegia alone.

Methods: After measuring cardiac function on a Langendorff apparatus, hearts were perfused with cardioplegia alone (controls), cardioplegia containing 500 [mu]m bupivacaine, or cardioplegia containing 2 mm lidocaine; were stored at 4[degrees]C for 12 h; and were then reperfused. Heart rate and left ventricular developed pressures were measured for 60 min. Maximum positive rate of change in ventricular pressure, oxygen consumption, and lactate dehydrogenase release were also measured.

Results: All bupivacaine-treated, four of five lidocaine-treated, and no control hearts beat throughout the 60-min recovery period. Mean values of heart rate, left ventricular developed pressure, maximum positive rate of change in ventricular pressure, rate-pressure product, and efficiency in bupivacaine-treated hearts exceeded those of the control group (P < 0.001 at 60 min for all). Mean values of the lidocaine group were intermediate. Oxygen consumption of the control group exceeded the other groups early in recovery, but not at later times. Lactate dehydrogenase release from the bupivacaine group was less than that from the control group (P < 0.001) but did not differ from baseline.  相似文献   

996.
In their recent review article, Tanvetyanon and Stiff [1] pointedout that hypocalcemia is a frequent side-effect of intravenousbisphosphonates. This adverse event is usually mild and exceptionallysymptomatic, with the principle risk factors being pre-existinghypovitaminosis D, previous parathyroid surgery and intestinalresections. A direct consequence of hypocalcemia  相似文献   
997.
998.
Patients with complaints of halitosis do seek treatment from physicians and dental practitioners, because of the fear that their halitosis may interfere with their social activities. Although the prevalence of halitosis has been reported to be as high as 50%, most physicians and dental practitioners are poorly informed about the causes and treatments of halitosis. In order to care for patients with complaints of halitosis a multidisciplinary team was established at the Erasmus Medical Centre, Rotterdam, The Netherlands. The team included a dental hygienist, an otorhinolaryngologist, and a dentist, who developed a special halitosis programme. One short press release regarding the establishment of the team, was provided to the national press-centre. In the out-patient clinic more than 700 patients were seen by the team. Using a structured questionnaire fed to a PC, patients answered questions regarding complaints about the oral cavity, the upper respiratory tract, the throat, their general health, their cleansing habits of the oral cavity, and prior experiences with general physicians, dental practitioners, and medical specialists. They underwent examinations of the extent of their halitosis, of the perioral and neck region, the oral cavity, the upper respiratory tract, and the upper digestive tract. Finally, the members of the team came to a joint diagnosis and a joint treatment plan for every individual patient. Of the first 700 consecutive patients around 90% had a natural dentition without removable partial dentures. More than 60% were diagnosed as having periodontal disease with pockets of 4 mm or more in the maxilla. This figure was more than 50% in the mandible. Around 95% had tongue coating.  相似文献   
999.
A decided attitude of expectation among many patients has given a new perspective to regenerative and plastic periodonta surgery. With authors emphasizing on the importance of gingival thickness, attempts are being made to obtain necessary information atraumatically and rapidly. Hence in the present study an attempt has been made to compare the two methods of assessing gingival thickness i.e transgingival probing and ultrasonographic method and also assess the gingival thickness in relation to central incisor lateral incisor and canine in Indian population. The gingival thickness was assessed in patients with healthy gingiva by both the methods. It was observed that transgingival probing method significantly over estimated the thickness of gingiva than the ultrasonographic method and the thickness of gingiva varies with morphology of the crown. It was concluded that compared to transgingival probing ultrasonographic method assesses gingiva thickness more accurately, rapidly and atraumatically.  相似文献   
1000.
The results of treatment of 7 patients with extensive hepatic hemangiomas are analysed. In 6 patients the diagnosis was established before the operation. The liver was resected in 4 patients. One patients with malignant degeneration of the hemangioma was inoperable, in another the hemangioma was not removed because of his old age, and still in another because the process had spread. The authors conclude that in large hemangiomas of the liver in young and middle-aged patients resection of the organ is indicated, especially if there is a destruction cavity and a rapid growth of hemangioma. The operation is not indicated in capillary, surface hemangiomas of a small size, old age of the patient, extension of the process in to the main vascular structures of the other hepatic lobe.  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