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   40282篇
  免费   9482篇
  国内免费   207篇
耳鼻咽喉   519篇
儿科学   874篇
妇产科学   678篇
基础医学   6945篇
口腔科学   1497篇
临床医学   5268篇
内科学   9372篇
皮肤病学   728篇
神经病学   3602篇
特种医学   2237篇
外科学   8167篇
综合类   530篇
一般理论   21篇
预防医学   4272篇
眼科学   687篇
药学   2318篇
  2篇
中国医学   20篇
肿瘤学   2234篇
  2022年   382篇
  2021年   621篇
  2020年   459篇
  2018年   627篇
  2017年   590篇
  2016年   771篇
  2015年   1093篇
  2014年   1835篇
  2013年   2743篇
  2012年   1517篇
  2011年   1494篇
  2010年   1697篇
  2009年   1806篇
  2008年   1472篇
  2007年   1316篇
  2006年   1473篇
  2005年   1349篇
  2004年   1294篇
  2003年   1240篇
  2002年   1259篇
  2001年   628篇
  2000年   475篇
  1999年   729篇
  1998年   1003篇
  1997年   960篇
  1996年   995篇
  1995年   932篇
  1994年   796篇
  1993年   717篇
  1992年   716篇
  1991年   684篇
  1990年   625篇
  1989年   681篇
  1988年   717篇
  1987年   695篇
  1986年   665篇
  1985年   704篇
  1984年   665篇
  1983年   668篇
  1982年   750篇
  1981年   682篇
  1980年   682篇
  1979年   585篇
  1978年   616篇
  1977年   598篇
  1976年   530篇
  1975年   448篇
  1974年   424篇
  1973年   397篇
  1972年   397篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
The intrauterine position occupied by a rodent fetus influences the amount of testosterone to which it is exposed before birth. Animals that are gestated between two male fetuses (2M) are exposed to higher circulating levels of testosterone than are animals positioned between two female fetuses (2F) and there are reliable differences in the reproductive physiology and behavior of 2M and 2F animals when adult. To determine whether intrauterine position modifies development of the central nervous system, we examined the sexually dimorphic spinal nucleus of the bulbocavernosus (SNB) in male and female gerbils from known intrauterine positions. We found that adult 2M female gerbils had 16% more SNB motoneurons than did 2F females. 2M males did not differ from 2F males in SNB motoneuron number, but the bulbocavernosus muscle, which is innervated by SNB motoneurons, was approximately 50% larger in 2M than in 2F males. These data indicate that intrauterine position can influence the morphology of the sexually dimorphic SNB neuromuscular system.  相似文献   
52.
A 7-cm anterior mediastinal tumor in an 80-year-old woman was found by light and electron microscopy to be a neuroblastoma. Immunoreactivity for neuron-specific enolase, synaptophysin, and chromogranin supported the diagnosis. Neuroblastoma is an uncommon tumor in adults and we are not aware of a previous report of such a tumor in a patient of this age.  相似文献   
53.
54.
The aim of the study was the investigation of the biochemical condition of elements likely to directly participate in active closing of the urethral lumen. We estimated glycogenolysis in urinary bladder, perivesical connective tissue and levator ani muscle (LAM) samples obtained intraoperatively from 80 stress incontinent women. Glycogen content as well as activities of active and total glycogen phosphorylase and acid exo-1,4-alpha-glucosidase were measured. Material from the urinary bladder and perivesical connective tissue was insignificantly altered, and glycogen contents in the bladder (2.03±1.38 g/100 g wet tissue) were considered to be normal. In the LAM glycogenolysis was much more activated than in other tissues (p<0.001 by Fischer's exact test). Of LAM specimens 78% (22/28) revealed imbalanced biochemistry of glycogen with activation of hydrolytic decomposition. We conclude that stress urinary incontinence in women is frequently associated with metabolic alterations in the periurethral striated fibres. This study indirectly supports our recent hypothesis on the pathogenesis of the disease in terms of muscle fibre type transitions.  相似文献   
55.
Objective: Our purpose was to determine whether insulin-like growth factors I and II preferentially stimulate uterine leiomyoma cells versus myometrial cells in monolayer culture.Study design: Leiomyomas and normal myometrium were obtained at hysterectomy from five premenopausal women. Specimens were enzymatically digested for use in primary monolayer cell cultures. By use of serum-free media, insulin-like growth factor I or II was added in 1, 10, and 100 ng/ml concentrations to both cell types with the patient serving as her own control. Cell number, prolactin production, and proliferative index values were measured on day 15 of cell culture.Results: Significant increases in cell number were found in the leiomyoma cultures (p < 0.05) treated with 10 and 100 ng/ml insulin-like growth factors I but not with insulin-like growth factos II. Neither factor exerted a stimulatory effect on myometrial cells.Conclusion: Insulin-like growth factor sI preferentially stimulates leiomyoma cells in monolayer culture. These results suggest an autocrine-paracine role in vivo for this factor in conjuction with gonadal steroids in promoting leiomyoma growth.  相似文献   
56.
57.
Background: Expanding upon our experience with laparoscopic surgery for colonic benign and malignant processes and for bowel obstruction, we have reviewed our experience with minimal access laparoscopic surgery for complicated diverticular disease. We propose an approach of surgical care incorporating diagnostic laparoscopy in those not responding to medical therapy alone. Methods: Our study includes data from two different surgical teams working in separate hospital-and-patient environments. Our theory that laparoscopy could be widely applicable to this complex disease process is borne out by experience in both locations. One hundred forty-eight patients were managed by laparoscopic or laparoscopically assisted methods with 18 patients requiring drainage only without resection. Results: Our management of 148 of 164 patients (90%) by laparoscopic approach was successful, with a very acceptable morbidity of 5% in the elective cases and decreased ileus (20% of open vs 7% laparoscopic) in acute complicated cases. Elective resections required hospitalization of 4–5 days, demonstrating the benefits of incorporating laparoscopy in the care of these cases, particularly when compared to standard open procedures requiring 8 days' hospitalization. Conclusions: We believe complications of diverticular disease including abscess, perforation, fistula, and bleeding can potentially be managed in this way by minimal access procedures, decreasing postoperative wound problems, decreasing length of hospitalization and overall morbidity, and improving patient care.  相似文献   
58.
Immunology     
A selection of interesting papers that were published in the two months before our press date in major journals most likely to report significant results in immunology.  相似文献   
59.
60.
Case report 733     
Calcific tendinitis at the site of origin of the rectus femoris muscle is a rare lesion. Presumed to be formed by deposition of hydroxyapatite crystals, this entity may be confused with other lesions such as os acetabuli or posttraumatic abnormalities. The characteristic location and appearance of the calcifications in a symptomatic patient with no history of trauma should allow diagnosis and subsequent symptomatic therapy.  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