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   825篇
  免费   56篇
  国内免费   10篇
耳鼻咽喉   14篇
儿科学   16篇
妇产科学   13篇
基础医学   128篇
口腔科学   43篇
临床医学   68篇
内科学   247篇
皮肤病学   14篇
神经病学   58篇
特种医学   25篇
外科学   83篇
综合类   1篇
一般理论   1篇
预防医学   38篇
眼科学   6篇
药学   66篇
中国医学   3篇
肿瘤学   67篇
  2024年   3篇
  2023年   17篇
  2022年   36篇
  2021年   58篇
  2020年   41篇
  2019年   37篇
  2018年   33篇
  2017年   34篇
  2016年   25篇
  2015年   27篇
  2014年   46篇
  2013年   38篇
  2012年   70篇
  2011年   75篇
  2010年   41篇
  2009年   33篇
  2008年   44篇
  2007年   43篇
  2006年   31篇
  2005年   28篇
  2004年   21篇
  2003年   15篇
  2002年   7篇
  2001年   7篇
  2000年   11篇
  1999年   4篇
  1998年   7篇
  1997年   3篇
  1996年   4篇
  1995年   1篇
  1994年   1篇
  1993年   2篇
  1992年   13篇
  1991年   4篇
  1990年   3篇
  1989年   4篇
  1988年   1篇
  1987年   5篇
  1986年   1篇
  1985年   2篇
  1984年   2篇
  1983年   3篇
  1980年   3篇
  1979年   3篇
  1975年   1篇
  1974年   2篇
  1969年   1篇
排序方式: 共有891条查询结果,搜索用时 0 毫秒
141.
An 18-year-old girl presented with abdominal pain and a tumor was subsequently detected in the jejunum. We therefore carried out a wedge resection of the jejunum. The diagnosis of GIST was confirmed histologically, and a mutation in exon 9 of the c-kit gene was observed. GISTs are rare in pediatric populations and pediatric GISTs occur predominantly in females and are characterized by a multifocal gastric location and a wild-type phenotype for the c-kit genes. The features of pediatric GISTs of the small intestine have not yet been categorized, and to date, only 11 cases in patients younger than 18 years have been reported. These cases did not occur primarily in females and tended to present as single tumors with mutations in the c-kit gene. This suggests that these cases do not have the same features as pediatric gastric GISTs, but instead are similar to adult GISTs. In pediatric populations, GISTs of the small intestine were expected to show a better response to imatinib treatment than gastric GISTs because of the alterations in the c-kit gene.  相似文献   
142.
Citation Kikuchi‐Arai M, Murakami T, Utsunomiya H, Akahira J, Suzuki‐Kakisaka H, Terada Y, Tachibana M, Hayasaka S, Ugajin T, Yaegashi N. Establishment of long‐term model throughout regular menstrual cycles in immunodeficient mice. Am J Reprod Immunol 2010 Problem The number of uterus natural killer (NK) cells change through the menstrual cycle, but the origin of uterus NK cell was not unclear. Our aims are to study whether we can reproduce repetition of menstrual cycle and to reveal the origin of uterus NK cells. Method of study Endometrial samples were obtained from fertile women, and the tissues were transplanted into ovariectomized non‐obese diabetic (NOD)/severe combined immunodeficiency (SCID)/γCnull (NOG) mice. Mice were treated with sex hormones which were in accord with human menstrual cycle. Results The replants showed similar histological changes as in eutopic endometrium repeatedly. CD56‐positive, CD16‐negative NK cells increased significantly during the treatment with estradiol and progesterone combination. Conclusion Histological assessment demonstrated that this model of NOG mice repeatedly exhibited regular menstrual cycles, and this model mimicked not ‘ectopic endometrium’, but ‘eutopic endometrium’ in humans. Change in number of NK cells suggested that NK cell might be derived from the endometrium.  相似文献   
143.
About half of all cancer patients show a syndrome of cachexia, characterized by anorexia and loss of adipose tissue and skeletal muscle mass. Cachexia can have a profound impact on quality of life, symptom burden, and a patient’s sense of dignity. It is a very serious complication, as weight loss during cancer treatment is associated with more chemotherapy-related side effects, fewer completed cycles of chemotherapy, and decreased survival rates. Numerous cytokines have been postulated to play a role in the etiology of cancer cachexia. Cytokines can elicit effects that mimic leptin signaling and suppress orexigenic ghrelin and neuropeptide Y (NPY) signaling, inducing sustained anorexia and cachexia not accompanied by the usual compensatory response. Furthermore, cytokines have been implicated in the induction of cancer-related muscle wasting. Cytokine-induced skeletal muscle wasting is probably a multifactorial process, which involves a protein synthesis inhibition, an increase in protein degradation, or a combination of both. The best treatment of the cachectic syndrome is a multifactorial approach. Many drugs including appetite stimulants, thalidomide, cytokine inhibitors, steroids, nonsteroidal anti-inflammatory drugs, branched-chain amino acids, eicosapentaenoic acid, and antiserotoninergic drugs have been proposed and used in clinical trials, while others are still under investigation using experimental animals. There is a growing awareness of the positive impact of supportive care measures and development of promising novel pharmaceutical agents for cachexia. While there has been great progress in understanding the underlying biological mechanisms of cachexia, health care providers must also recognize the psychosocial and biomedical impact cachexia can have.  相似文献   
144.

Purpose

We compared the detectability of liver metastases on 2- and 3-phase images using robust statistical methods. Nine radiologists evaluated unenhanced CT plus portal venous phase (2-phase) images and 2-phase plus hepatic arterial phase (HAP) (3-phase) images.

Materials and methods

Our study included 54 patients with primary malignant tumors who underwent 3-phase hepatic dynamic CT more than twice to screen for liver metastases; 24 had 1–6 liver metastases measuring 4–27 mm in diameter (median 13 mm). The other 30 had no metastases. Nine board-certified radiologists participated in our observer performance study. They specified the location of the metastatic lesions and rated the probability of metastatic nodules on 2-phase images acquired with and without HAP imaging. We used jackknife alternative free-response receiver operating characteristic (JAFROC) analysis to compare their performances.

Results

For all radiologists the area under the curve without and with HAP imaging was 0.86 and 0.88, respectively; the difference was significant (p = 0.04). For metastases smaller than 10 mm the averaged lesion localization fraction without and with HAP imaging was 0.17 and 0.26 (p < 0.01).

Conclusion

Adding HAP to 2-phase imaging improved the detectability of liver metastases, especially of lesions smaller than 10 mm.  相似文献   
145.
146.
The otolith-ocular reflex in patients with episodic lateral tilt sensation without any other vestibular symptoms was assessed using ocular vestibular evoked myogenic potentials (oVEMP). Ten patients (6 men and 4 women, mean age=53.5) were enrolled. All patients had episodic lateral tilt sensation. Patients with a medical history of rotatory vertigo, loss of consciousness, head trauma, or symptoms or signs of central nervous dysfunction or proprioceptive dysfunction and those who had been definitely diagnosed with a disease that causes disequilibrium were excluded. All of the 10 patients had oVEMP tests and cervical VEMP (cVEMP) tests and underwent caloric tests. Eight of the 10 patients showed unilateral absence of oVEMP, one displayed a bilateral absence, and one displayed normal oVEMP. Concerning cVEMP, 4 patients showed a unilateral absence of cVEMP, one displayed unilaterally decreased responses and 5 displayed normal cVEMP. All patients showed normal bilateral caloric responses. The present study showed that patients with episodic lateral tilt sensation displayed abnormal otolith-ocular reflexes, as shown by their oVEMP, suggesting that these patients were suffering from utricular dysfunction.  相似文献   
147.
Infectious mononucleosis (IM) is a clinical syndrome caused by primary infection with Epstein–Barr virus (EBV) that is common in adolescents. In adults, particularly in elderly people, the clinical picture of IM tends to be atypical, often leading to a diagnostic challenge. Diagnosis is also complicated because infection with EBV can induce the synthesis of cross-reacting immunoglobulin M antibodies for other herpesviruses. We report an unusual case of infectious mononucleosis in a 34-year-old immunocompetent adult. Epidemiological studies indicate that the average age of primary EBV infection in developed countries is increasing. IM with atypical presentation will be a diagnostic challenge in the future as the number of EBV-naïve adults increases.  相似文献   
148.
149.
GeroScience - The rs1333049 (G/C) polymorphism located on chromosome 9p21.3 is a candidate to influence extreme longevity owing to its association with age-related diseases, notably coronary artery...  相似文献   
150.
PURPOSE: To investigate the microleakage of cervical cavities restored with flowable composites in conjunction with an all-in-one adhesive system (AQ Bond) and an experimental two-step self-etching primer system (ABF) after thermocycling or flexural load cycling. METHODS: 180 wedge-shaped cervical cavities on the labial surfaces of bovine incisors were treated with AQ Bond or ABF according to the manufacturers' instructions. The treated cavities were filled with one of three flowable composites (AElite Flo, Metafil Flo or Protect Liner F). Ten of 30 specimens for each group were immersed in 0.5% basic fuchsin solution immediately after finishing of the restorations. Specimens to be subjected to thermocycling (5-60 degrees C, 15 seconds dwell time, 5000 cycles) or to flexural load cycling (approximately 0.5 mm labio-lingual displacement at the incisal edge, 10,000 cycles, 1 Hz) prior to immersion in the dye were also prepared. After 24-hour storage in the dye solution, the teeth were sectioned longitudinally through the center of the restorations, and the degrees of dye penetration scored. The microleakage scores of a hybrid composite (Clearfil AP-X) obtained from our previous study were used for comparison. The data were analyzed with the Kruskal-Wallis test and the Mann-Whitney U-test (P < 0.05). RESULTS: No significant differences in the microleakage patterns and scores were found among the flowable composites. On the other hand, significant differences in the microleakage patterns and scores were observed between the flowable and the hybrid composites. Thermocycling caused deterioration of marginal integrity, and the flowable composites showed more microleakage than the hybrid composite. In contrast, flexural load cycling did not cause deterioration of the marginal integrity when the cavities were filled with the flowable composites. Statistical analysis also revealed that the adhesive systems played a large role in the microleakage patterns.  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