全文获取类型
收费全文 | 42799篇 |
免费 | 2224篇 |
国内免费 | 213篇 |
专业分类
耳鼻咽喉 | 372篇 |
儿科学 | 818篇 |
妇产科学 | 665篇 |
基础医学 | 5460篇 |
口腔科学 | 1100篇 |
临床医学 | 2879篇 |
内科学 | 10629篇 |
皮肤病学 | 623篇 |
神经病学 | 3075篇 |
特种医学 | 1539篇 |
外科学 | 8033篇 |
综合类 | 190篇 |
一般理论 | 1篇 |
预防医学 | 1360篇 |
眼科学 | 601篇 |
药学 | 3066篇 |
中国医学 | 133篇 |
肿瘤学 | 4692篇 |
出版年
2023年 | 247篇 |
2022年 | 280篇 |
2021年 | 949篇 |
2020年 | 516篇 |
2019年 | 681篇 |
2018年 | 842篇 |
2017年 | 657篇 |
2016年 | 772篇 |
2015年 | 833篇 |
2014年 | 1049篇 |
2013年 | 1253篇 |
2012年 | 1977篇 |
2011年 | 2131篇 |
2010年 | 1162篇 |
2009年 | 928篇 |
2008年 | 1768篇 |
2007年 | 1874篇 |
2006年 | 1831篇 |
2005年 | 1881篇 |
2004年 | 1882篇 |
2003年 | 1810篇 |
2002年 | 1800篇 |
2001年 | 1688篇 |
2000年 | 1639篇 |
1999年 | 1573篇 |
1998年 | 564篇 |
1997年 | 464篇 |
1996年 | 410篇 |
1995年 | 368篇 |
1994年 | 358篇 |
1993年 | 310篇 |
1992年 | 1022篇 |
1991年 | 952篇 |
1990年 | 835篇 |
1989年 | 926篇 |
1988年 | 788篇 |
1987年 | 716篇 |
1986年 | 761篇 |
1985年 | 691篇 |
1984年 | 443篇 |
1983年 | 387篇 |
1982年 | 199篇 |
1981年 | 193篇 |
1979年 | 313篇 |
1978年 | 246篇 |
1977年 | 214篇 |
1975年 | 221篇 |
1974年 | 201篇 |
1973年 | 178篇 |
1971年 | 180篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Evidence by cellular mosaicism for monoclonal metastasis of spontaneous mouse mammary tumors 总被引:2,自引:0,他引:2
Female (SHN X C3H/He)F1 mice carrying spontaneous mammary tumors with cellular mosaicism with respect to isozymes of phosphoglycerate kinase (PGK) showed a high incidence of lung metastases. On resection of successively appearing mammary tumors, mice survived a maximum of 8 tumors. In these mice with multiple primary mammary tumors and multiple metastases, not only each individual metastasis but also all the metastases in the same lung had the same pattern of PGK isozymes and the same histologic type in the PGK-mosaic background of the host, indicating the monoclonal origin of these metastases. In several cases, this single pattern of metastatic colonies coincided with that of only one of several primary tumors, indicating that this tumor had metastasized. In these cases, these tumors were not necessarily the earliest of the primary tumors, and they were not located in any particular site. 相似文献
52.
H Tsukuma A Oshima T Hiyama I Fujimoto H Yamano M Tanaka 《International journal of epidemiology》1987,16(4):579-583
In order to examine time trends of the prevalences of HBeAg positives among HBV carriers in Japan, we analysed data on HBeAg of HBsAg positive voluntary blood donors (23,560 males, and 8659 females) at the Osaka Red Cross Blood Centre between January 1977 and March 1984. Age-specific prevalences of HBeAg positives decreased year by year for both sexes, especially for those in their teens and twenties. The prevalences of HBeAg positives decreased with age, but at any given age it was lower for the later than for the earlier birth cohorts. Although reasons for the secular declines are unknown, the findings suggest that the prevalence of HBeAg positives among HBV carriers will continue to decrease in Japan. This, together with the immunization programme implemented this year, may lead to a future reduction in the risk of HBV related liver diseases in Japan. 相似文献
53.
54.
K Tanaka Y Miyake S Sasaki Y Ohya S Miyamoto I Matsunaga T Yoshida Y Hirota H Oda 《Magnesium research》2006,19(4):268-275
There have only been a few studies on the role of mineral intake in tooth loss. We investigated the association between mineral intake and the prevalence of tooth loss in Japan. We used the baseline data on 1002 pregnant women who were enrolled in the Osaka Maternal and Child Health Study between November 2001 and March 2003. Tooth loss was defined as the previous extraction of one or more teeth. Nutrient intake was assessed by a validated diet history questionnaire. Prevalence odds ratios and confidence intervals were estimated by applying a multiple logistic regression model. The adjusted odds ratio upon comparison of the highest quartile with the lowest quartile of magnesium intake was 0.64 (95% confidence interval, 0.42-0.99), showing a tendency for an inverse dose-response relationship (p for linear trend = 0.05). There were no associations between the level of consumption of calcium, phosphate, iron, zinc, or copper and tooth loss. The present findings suggest that intake of magnesium is related to reduced prevalence of tooth loss among young Japanese women. 相似文献
55.
Hidero Minami Ryo Matsutani Atsushi Mizokami Mikio Namiki 《International journal of urology》2007,14(4):368-369
Abstract: A 19-year-old woman presented at our hospital with acute urinary retention in September 2005. She had experienced the same chief complaint twice previously. She had used non-steroidal anti-inflammatory drugs before acute urinary retention. The results of physical examinations were unremarkable, and her neurologic signs were not remarkable. The basic laboratory test values were all normal and a psychiatric assessment indicated that her symptoms were not psychogenic. Magnetic resonance imaging was carried out, but revealed only a slight bulging in the L3/L4/L5 disk. Water cystometry showed acontractile detrusor. We made a diagnosis of acute urinary retention as a result of non-steroidal anti-inflammatory drugs because of her use of such drugs before the development of symptoms on multiple occasions. This patient was regularly followed up as an outpatient, and she could void smoothly in February 2006. This is the first report which acute urinary retention associated with non-steroidal anti-inflammatory drugs in Japan. 相似文献
56.
Katsuyoshi Habiro Hiroaki Shimmura Sakiko Kobayashi Motoko Kotani Yasuo Ishida Kazunari Tanabe Hiroshi Toma Ryo Abe 《American journal of transplantation》2005,5(4):702-711
Previously, we reported that allogeneic skin grafts were rapidly rejected by CD28 and CD40 ligand double deficient mice mediated by CD8+ T cells. These results indicated that some elements in addition to CD28- and CD40-mediated costimulation provide stimulatory signals for the activation of donor-specific CD8+ T cells. In this report, we investigated the role of inflammation associated with transplantation on costimulation-independent priming of CD8+ T cell during graft rejection. B6 RAG1 KO mice were transplanted with BALB/c-skin and adoptively transferred with syngeneic CD8+ T cells the same day or 50 days after transplantation. When blockade of CD28- and CD40-mediated costimulation failed to prevent acute rejection of freshly transplanted skin grafts, it efficiently delayed rejection of well-healed skin grafts. These results showed that factors associated with transplantation have essential roles in inducing costimulation blockade-resistant allograft rejection. Costimulation blockade failed to prevent acute graft-infiltration of NK cells and increasing expression of intragraft IL-12 and IL-15. These factors may trigger the graft-infiltration and priming of CD8+ T cells to induce costimulation blockade-resistant allograft rejection. 相似文献
57.
Self-expandable metallic stent for unresectable malignant strictures in the esophagus and cardia 总被引:2,自引:0,他引:2
Shigeru Lee Harushi Osugi Taigo Tokuhara Masashi Takemura Masahiro Kaneko Yoshinori Tanaka Yushi Fujiwara Satoshi Nishizawa Hiroshi Iwasaki Shigefumi Suehiro 《The Japanese Journal of Thoracic and Cardiovascular Surgery》2005,53(9):470-476
Objective Self-expandable metallic stent (EMS) placement has been the first choice for dysphagia because of the certainty over its safety,
low invasiveness, and immediate efficacy. However, there still remain some problems in relation to the EMS placement site
and anticancer therapies before and after EMS placement. Methods: Consecutive 78 patients in whom EMS was placed due to the unresectable malignant stricture in the esophagus or cardia from
July 1995 to August 2003 in our department were studied. Results: Gastroesophageal reflux was found in 5 of 8 patients after placement of conventional EMS for the stricture in the gastroesophageal
junction. Meanwhile, acid and bile reflux into the esophagus were not detected by pH and bilirubin monitoring, respectively,
in 6 patients after placement of the EMS with an anti-reflux mechanism for the stricture in the gastroesophageal junction.
The median survival period of all patients after EMS placement was 123 days. The median survival period of 7 patients with
radiotherapy only after EMS placement was 138 days and that of 17 patients with radiotherapy before EMS placement was 60 days,
which was shorter than that of the former (p<0.05). On the other hand, the median survival period after hospital admission
due to dysphagia of these 7 patients was longer than that of 17 patients with radiotherapy only before EMS placement, although,
the difference was not significant. Conclusion: EMS with an antireflux mechanism is not commercially available in Japan and approval is urgently required. The indication
of radiotherapy associated with EMS placement is to be studied further. 相似文献
58.
A 68-year-old man had subacute cerebellar degeneration and a non-Hodgkin's lymphoma. Using an immunoblotting method, we found serum antibodies to rat cerebral 250-kd and 110-kd and cerebellar 110-kd acidic cytoplasmic proteins. The antibodies did not react unless the antigens were prepared soon after death with protease inhibitors. Two hundred fifty-kd and 110-kd proteins are minor components of soluble cytoplasmic proteins of the brain. The molecular weights differed from other soluble brain-specific proteins already characterized. 相似文献
59.
60.
Electrical stimulation of several brain sites produces profound analgesia in humans, and inhibits nocifensor reflexes in animal studies. Responses of the dorsal horn nociceptive neurons evoked by stimulation onto the receptive fields are also inhibited by brain stimulation. These brain sites are Periaqueductal Gray Matter (PAG), Nucleus Raphe Magnus (NRM), Nucleus Reticularis magnocellularis (NRmc), Locus Coeruleus (LC), Lateral Hypothalamus, and others. We have explained in a general way the mechanism of these stimulation produced analgesia. The mechanism of PAG stimulation analgesia is partly due to an activation of serotonin containing neurons which descend from NRM to the spinal dorsal horn and activated by PAG stimulation. Activation of NRM neurons may produce inhibition of the nociceptive neurons of the dorsal horn by the mechanism of direct postsynaptic inhibition. Currently there is no evidence to support the theory of presynaptic inhibition. Endogenous opioid peptides do not play an important role in PAG stimulation analgesia. On the other hand, the mechanism of NRmc or LC stimulation analgesia may be due to an activation of noradrenaline containing neurons which similarly inhibit the dorsal horn nociceptive neurons in the spinal cord. At present, it still remains unknown whether endogenous opioid peptides play an important role in this type of analgesia. 相似文献