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   1273篇
  免费   46篇
  国内免费   6篇
耳鼻咽喉   7篇
儿科学   5篇
妇产科学   63篇
基础医学   206篇
口腔科学   52篇
临床医学   95篇
内科学   347篇
皮肤病学   2篇
神经病学   48篇
特种医学   41篇
外科学   175篇
综合类   2篇
预防医学   32篇
眼科学   6篇
药学   91篇
肿瘤学   153篇
  2022年   6篇
  2021年   11篇
  2020年   10篇
  2019年   16篇
  2018年   17篇
  2017年   11篇
  2016年   12篇
  2015年   14篇
  2014年   13篇
  2013年   27篇
  2012年   54篇
  2011年   47篇
  2010年   37篇
  2009年   28篇
  2008年   47篇
  2007年   58篇
  2006年   55篇
  2005年   71篇
  2004年   67篇
  2003年   58篇
  2002年   65篇
  2001年   65篇
  2000年   64篇
  1999年   56篇
  1998年   23篇
  1997年   11篇
  1996年   6篇
  1995年   10篇
  1994年   7篇
  1992年   26篇
  1991年   26篇
  1990年   22篇
  1989年   32篇
  1988年   23篇
  1987年   21篇
  1986年   23篇
  1985年   23篇
  1984年   32篇
  1983年   14篇
  1982年   13篇
  1981年   7篇
  1979年   9篇
  1978年   7篇
  1977年   9篇
  1975年   5篇
  1974年   7篇
  1973年   8篇
  1971年   10篇
  1970年   5篇
  1968年   6篇
排序方式: 共有1325条查询结果,搜索用时 750 毫秒
1.
PURPOSE: The purpose of this study was to examine changes of chewing movement and masticatory efficiency during the natural course of nonreducing disc displacement of the temporomandibular joint (TMJ). PATIENTS AND METHODS: The subjects were 15 patients who had been diagnosed with nonreducing disc displacement of the TMJ but had received no treatment. Chewing movement and masticatory efficiency were examined at the initial visit and at a mean follow-up of 21.7 months, using mandibular kinesiography and adenosine triphosphate ebteric-coated granules. As a control, 23 persons who had no current or previous TMJ symptoms were studied. RESULTS: The patients' clinical signs and symptoms tended to be alleviated during the follow-up period. In normal controls, chewing movement showed lateral excursion to the chewing side on both the right and left sides. In patients, chewing movement at the initial visit showed lateral excursion to the chewing side during chewing on the TMJ affected side, but no such deviation was noted during chewing on the TMJ unaffected side in the horizontal plane. However, chewing movement at follow-up became similar to that of controls. In patients, masticatory efficiency became better during the natural course, although that at follow-up did not always reach the control's level. CONCLUSION: In untreated patients with nonreducing disc displacement of the TMJ, chewing movement and masticatory efficiency tend to improve spontaneously.  相似文献   
2.
3.
Six normal men performed cycle ergometer exercise from 50 W to 125 W in a room maintained at 26 degrees C. Capsaicin was introduced by iontophoresis into the forearm skin. Forearm skin blood flow (FSBF) during graded exercises before and after capsaicin treatment was measured by laser Doppler flowmetry. Forearm skin blood flow before capsaicin treatment increased depending on the intensity of exercise. However, forearm skin blood flow 24 hours after capsaicin treatment scarcely increased during graded exercise. The cause of this capsaicin effect was discussed.  相似文献   
4.
5.
Annulo-aortic ectasia is an extremely rare complication of Gaucher's disease. We report successful surgery in a patient with Gaucher's disease complicated by annulo-aortic ectasia and aortic dissection. Cabrol's operation was accomplished without bleeding or sternal adaptation problems.  相似文献   
6.
PROBLEM: In order to investigate the role of macrophage colony-stimulating factor (M-CSF) and monocyte chemoattractant protein -1 (MCP-1) in human ovulation, we studied the regulation of M-CSF and MCP-1 in cultured human granulosa cells. METHOD OF STUDY: Immortalized granulosa cells (GC1a) were cultured in serum-free medium, and incubated with interleukin (IL)-1alpha, IL-1 receptor antagonist (ra) and tumor necrosis factor (TNF)-alpha. The supernatants were collected, and M-CSF and MCP-1 were measured by ELISA. RESULTS: The levels of M-CSF and MCP-1 were increased after treatment with IL-1alpha (1 nm) and TNF-alpha (1 nm) in a time-dependent manner. The levels of M-CSF and MCP-1 were significantly increased after treatment with IL-1alpha and TNF-alpha in a dose-dependent manner. However, the levels of M-CSF and MCP-1 were significantly decreased by treatment with IL-1alpha (1 nm) and/or increasing concentrations of IL-1 ra. CONCLUSIONS: Our data indicated that M-CSF and MCP-1 were regulated by IL-1alpha and TNF-alpha. It was suggested that M-CSF and MCP-1 may play an important role in human preovulatory processes.  相似文献   
7.
Human endometrial stromal cells (ESC) can produce a variety of chemokines, especially after inflammatory stimulation. Interferon-gamma-inducible protein-10 (IP-10) is a potent chemoattractant for lymphocytes, and belongs to the family of non-ELR CXC chemokines. The expression of IP-10 in ESC after stimulation with interferon-gamma (IFN-gamma), interleukin-1 beta (IL-1 beta), tumour necrosis factor-alpha (TNF-alpha), or lipopolysaccharide (LPS) was evaluated using an enzyme-linked immunosorbent assay and Northern blot analysis. A small amount of IP-10 protein was detected in the culture media of unstimulated ESC. The expression of IP-10 mRNA was detected in ESC. IFN-gamma, IL-1 beta, TNF-alpha and LPS significantly stimulated the expression of IP-10 mRNA and protein in ESC. These results suggest that the production of IP-10 by ESC is regulated by inflammatory mediators. The modulation of IP-10 concentrations in the local environment may contribute to the normal and pathological processes of human reproduction by regulating leukocyte trafficking in the endometrium.  相似文献   
8.
C57BL/6 mice were orally immunized with five weekly doses of 2 mg, 200 microgram, or 2 microgram of Helicobacter pylori (Sydney strain) whole-cell sonicate combined with cholera toxin. One week after the last vaccination, mice were challenged with 5 x 10(7) CFU of live H. pylori three times at 2-day intervals. At 6 or 18 weeks after the challenge, mice were sacrificed and bacterial cultures and histological studies of the stomach were performed. Vaccination with 2 mg/session or 200 microgram/session inhibited H. pylori colonization by 90 and 100%, respectively. These mice were considered protected. Lower levels of H. pylori-specific immunoglobulin A (IgA) were detected in fecal and saliva samples before challenge. However, a significant increase in IgA secretion in mucosal tissue and a higher labeling index for IgA-positive lumina of pyloric glands were noted in these mice in response to challenge and in a vaccine dose-dependent manner. In protected mice, however, severe gastritis characterized by marked infiltration of inflammation mononuclear cells was noted at 6 weeks after challenge, compared with the gastritis seen in unprotected mice or nonvaccinated, ordinarily infected mice. Marked expression of gamma interferon mRNA was detected in the stomach of all protected mice, and 50% of these mice expressed interleukin 4 (IL-4) or IL-5 mRNA. Our findings suggest that local secretory IgA antibody and severe postimmunization gastritis correlate well with protection of mice against H. pylori infection.  相似文献   
9.
We purified a 29-kDa Helicobacter pylori outer membrane protein (Omp29 protein) and cloned the gene encoding the protein from H. pylori strain ATCC 43504. The Omp29 gene corresponded to the reported JHP73 and the HP78-79 genes of H. pylori strains. A corresponding nucleotide fragment was detected in all 150 tested H. pylori clinical isolates by PCR or Southern blotting. The amplified Omp29-corresponding fragments were categorized into a ca. 770-bp-long group and a larger-fragment group. Sequence analysis indicated that the larger fragments were likely synthesized from the 770-bp fragments by insertion of an irrelevant fragment via 17-bp-long repeat sequences. Immunoblot analysis implies that the ca. 770-bp fragment is responsible for the protein homologous to Omp29, whereas the larger fragments are not responsible for those proteins or encoding antigenically distinct proteins. We postulate that the H. pylori outer membrane protein Omp29 can alter its antigenicity through gene modifications mediated by nucleotide transfer.  相似文献   
10.
Natural tooth loss represents a major medical issue within the elderly population, since it impairs masticatory function critical for oral intake of essential nutrition. Contribution of genetic factors has been implicated in the determination of natural tooth loss; degree of reduction in number of natural teeth remaining intact (NTI) varies among individuals; thus, heterogeneity in NTI might reflect genetic variation within the population. One candidate gene, the matrix Gla protein gene (MGP), has been implicated in the pathogenesis of bone loss through a repression of bone/tooth formation. We have investigated a possible association between the CA repeat polymorphism at the human MGP gene locus and the NTI in 458 elderly Japanese women. In 916 chromosomes tested, ten alleles of the polymorphic nucleotide repeat were observed (designated A1–A10), among which five alleles were regarded as major alleles to be tested for the association. Twenty-seven women who possessed an A6 allele (164 bp) had significantly higher NTI than the remaining participants (n=431), who did not carry an allele of that size (mean: 10.0 teeth vs 5.6 teeth; P=0.007, Mann-Whitney test). An eight-year longitudinal follow-up study of NTI suggested that the genetic variations at the MGP locus did not affect the rate of tooth loss in the elderly period. These results suggest that genetic variation at the MGP gene locus is associated with some determinants for tooth loss in elderly women.  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