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   36444篇
  免费   1841篇
  国内免费   93篇
耳鼻咽喉   691篇
儿科学   1306篇
妇产科学   1102篇
基础医学   4314篇
口腔科学   1307篇
临床医学   2992篇
内科学   6665篇
皮肤病学   706篇
神经病学   3290篇
特种医学   1306篇
外国民族医学   1篇
外科学   6076篇
综合类   168篇
一般理论   10篇
预防医学   3239篇
眼科学   852篇
药学   2351篇
中国医学   129篇
肿瘤学   1873篇
  2023年   368篇
  2022年   372篇
  2021年   807篇
  2020年   560篇
  2019年   688篇
  2018年   1212篇
  2017年   927篇
  2016年   1134篇
  2015年   1095篇
  2014年   1389篇
  2013年   1878篇
  2012年   2320篇
  2011年   2491篇
  2010年   1421篇
  2009年   1011篇
  2008年   1555篇
  2007年   1744篇
  2006年   1549篇
  2005年   1570篇
  2004年   1475篇
  2003年   1408篇
  2002年   1287篇
  2001年   792篇
  2000年   782篇
  1999年   658篇
  1998年   242篇
  1997年   197篇
  1996年   163篇
  1992年   382篇
  1991年   362篇
  1990年   377篇
  1989年   362篇
  1988年   342篇
  1987年   336篇
  1986年   337篇
  1985年   354篇
  1984年   268篇
  1983年   236篇
  1979年   279篇
  1978年   170篇
  1975年   165篇
  1974年   209篇
  1973年   207篇
  1972年   227篇
  1971年   181篇
  1970年   159篇
  1969年   203篇
  1968年   178篇
  1967年   160篇
  1966年   148篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
A thermal manikin of the size of a 1 kg premature baby has been constructed. The nonevaporative heat loss from eight different regions and the total heat loss were measured. The measurements of heat loss have high repeatability and the values are in good agreement with measurements of dry heat loss for premature babies, using indirect calorimetry. The heat losses from the manikin in a single-walled, air-heated incubator and on a recently described heated, water-filled mattress have been compared. The total heat loss was found to be 20 to 30 W/m2 with both methods at ambient temperatures between 15 degrees and 25 degrees C. Treatment on a heated, water-filled mattress provides a means of direct conductive heat input to the baby, with a conductive heat transfer coefficient of 0.4 W/degrees C or 21 W/m2 degrees C. The thermal manikin appears to provide an accurate method for assessment of the thermal conditions in neonatal care.  相似文献   
82.
Summary A method of dermaplaning for acne scarring using a skin graft knife is described. This surgical technique cannot be considered as a form of dermabrasion. Its advantages are reported.  相似文献   
83.
Progesterone secretion of cultured human granulosa cells treated with LHRH or its analogues was measured. Granulosa cells were also stimulated with LH, FSH, cAMP or forskolin. No differences could be observed in the progesterone basal secretion of cultures treated with or without LHRH or its analogues and after the various stimulations. It was concluded that the clinical experience that the sensitivity of ovaries for gonadotropins after LHRH desensitization is decreased could not be explained with the peripheral effects of LHRH on the granulosa cells. From the data obtained, the lack of LHRH receptors in the ovaries are suggested in humans.  相似文献   
84.
Retention is a major part of orthodontic treatment, not an optional secondary protocol. In recent years, studies investigating dentofacial changes during and after the growth period have led most clinicians to use fixed retention appliances after treatment. Fixed retainers can be attached to the teeth directly or indirectly. We present a practical, indirect method for bonding fixed retainers, using Sondhi Rapid-set Indirect Bonding Adhesive (3M Unitek, Monrovia, Calif).  相似文献   
85.
Hereditary gingival fibromatosis (HGF) is characterized by the slowly progressive fibrous enlargement of gingival tissue. It usually develops as an isolated disorder but can also be one feature of various syndromes. The currently preferred terminology of these syndromes mainly describes the clinical features of the disorder without identifying the cause. In this report, we present the 5-year follow up of a family with HGF and features of 3 previously described syndromes: Jones syndrome, Zimmerman-Laband syndrome, and HGF-hypertrichosis syndrome. The 45-year-old father had HGF, hypertrichosis, hearing loss, and short stubby fingers and toes with hypoplasia of the terminal phalanges and hypoplasia of the nails on the thumbs. The features of 13-year-old son were almost identical to those of his father except for hypertrichosis, but in addition he was mentally retarded. Although the 10-day-old son had HGF and defective fingers, the mother and 7-year-old daughter were unaffected. Owing to the overlap of these syndromes, we argue that the identification of the genetic pathways and mechanisms will be the most important factor in classifying these disorders, with the phenotype playing a minor role.  相似文献   
86.
87.
88.
In this note, we report a study of cryoprotectant carbohydrate (glucose, fructose, mannose and maltose) effects on the reconstitution of calixarene based solid lipid nanoparticle (SLN) suspensions after freeze-drying, studied by atomic force microscopy and photon correlation spectroscopy. All carbohydrates tested showed excellent cryoprotection and redispersion properties with the calixarene based SLNs.  相似文献   
89.
Ileal and jejunal resections were carried out to investigate their effect on the faecal bile acid excretion and on the development of 1,2-dimethylhydrazine (DMH)-induced colonic cancer in rats. Both resection types raise the total daily faecal bile acid level compared to the control sham-operated group, whereas ileal resection has a more pronounced effect. The incidence of tumours was found higher in groups with enhanced faecal bile acid level. Our findings show a connection between the daily faecal bile acid excretion and the incidence of DMH-induced colonic cancer.  相似文献   
90.
R D Ballard  R M Bogin  J Pak 《Chest》1991,100(2):410-415
We assessed the bronchodilator response to a recently available ultrasonic nebulizer (USN) in a population of 17 stable asthmatic patients. These patients were also evaluated for bronchodilator response to two other aerosol delivery systems routinely used in standard clinical practice, the metered-dose inhaler (MDI) and the jet nebulizer (JN). Albuterol was administered from each of the delivery systems in the following manner: MDI, two actuations (180 micrograms); JN, 0.5 ml of 0.5 percent solution (2.5 mg) in 1.0 ml saline solution diluent; and USN, 0.5 ml of 0.5 percent solution (2.5 mg) in 2.5 ml saline solution diluent. Patients demonstrated significant bronchodilator responses to all three delivery systems (p less than 0.0001). The USN produced a greater percentage of increase in FEV1 15 minutes after treatment with albuterol (35.8 +/- 2.3 percent) than either the MDI (18.2 +/- 3.4 percent) or JN (20.8 +/- 3.1 percent) (p less than 0.005). The mean percentage of increase in FE1 observed over a 4-h period after treatment was also greater for the USN (26.5 +/- 2.5 percent) than either the MDI (18.8 +/- 1.8 percent) or JN (15.0 +/- 1.6 percent) (p less than 0.001). We conclude that the USN yields effective bronchodilation in a population of stable asthmatics.  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