全文获取类型
收费全文 | 1255篇 |
免费 | 62篇 |
国内免费 | 18篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 18篇 |
妇产科学 | 29篇 |
基础医学 | 128篇 |
口腔科学 | 27篇 |
临床医学 | 69篇 |
内科学 | 327篇 |
皮肤病学 | 14篇 |
神经病学 | 69篇 |
特种医学 | 55篇 |
外科学 | 377篇 |
综合类 | 8篇 |
预防医学 | 39篇 |
眼科学 | 1篇 |
药学 | 46篇 |
中国医学 | 7篇 |
肿瘤学 | 120篇 |
出版年
2023年 | 6篇 |
2021年 | 32篇 |
2020年 | 9篇 |
2019年 | 20篇 |
2018年 | 21篇 |
2017年 | 15篇 |
2016年 | 26篇 |
2015年 | 20篇 |
2014年 | 32篇 |
2013年 | 36篇 |
2012年 | 60篇 |
2011年 | 66篇 |
2010年 | 36篇 |
2009年 | 32篇 |
2008年 | 55篇 |
2007年 | 59篇 |
2006年 | 61篇 |
2005年 | 61篇 |
2004年 | 82篇 |
2003年 | 71篇 |
2002年 | 75篇 |
2001年 | 59篇 |
2000年 | 58篇 |
1999年 | 43篇 |
1998年 | 18篇 |
1997年 | 10篇 |
1995年 | 11篇 |
1992年 | 18篇 |
1991年 | 11篇 |
1990年 | 16篇 |
1989年 | 14篇 |
1988年 | 13篇 |
1987年 | 10篇 |
1986年 | 13篇 |
1985年 | 13篇 |
1984年 | 11篇 |
1983年 | 13篇 |
1982年 | 5篇 |
1979年 | 7篇 |
1978年 | 6篇 |
1976年 | 7篇 |
1974年 | 5篇 |
1973年 | 5篇 |
1972年 | 10篇 |
1971年 | 5篇 |
1970年 | 8篇 |
1969年 | 9篇 |
1968年 | 5篇 |
1967年 | 19篇 |
1966年 | 5篇 |
排序方式: 共有1335条查询结果,搜索用时 62 毫秒
11.
Study on effects of life review activities on the quality of life of the elderly: a randomized controlled trial 总被引:1,自引:0,他引:1
BACKGROUND: The objective of this study was to evaluate the mid-term efficacy of life review activities on the quality of life (QOL) of the elderly by conducting a randomized controlled trial, and to identify the factors that should be taken into consideration when conducting life review activities. METHODS: Written consent was obtained from 80 of the 97 eligible elderly persons. After randomly assigning them to two groups, an intervention group and a control group, group life review activities were conducted in the intervention group and discussion activities about health were conducted in the control group. In both the intervention group and the control group, life satisfaction, self-esteem, depression, and hopelessness were evaluated using self-rating scales at three points: at baseline, immediately after completion of the 8 weeks of sessions, and 3 months after completion of the intervention. RESULTS: Repeated measures analysis of covariance showed significant differences between the two groups in the changes in scores for depression (p = 0.04) and hopelessness (p = 0.04). Regarding the factors that were associated with depression and hopelessness, 3 months after completion of the intervention, depression and hopelessness of a more severe nature at baseline and having greater unresolved conflicts in the past were extracted by multiple regression analysis. CONCLUSIONS: The results suggested that group life review activities have a role in assisting the developmental stage of old age and supporting mental health, and have mid- to long-term effectiveness in maintaining and improving the QOL of the elderly. 相似文献
12.
Ohashi E Ogi T Kusumoto R Iwai S Masutani C Hanaoka F Ohmori H 《Genes & development》2000,14(13):1589-1594
The Escherichia coli protein DinB is a newly identified error-prone DNA polymerase. Recently, a human homolog of DinB was identified and named DINB1. We report that the DINB1 gene encodes a DNA polymerase (designated polkappa), which incorporates mismatched bases on a nondamaged template with a high frequency. Moreover, polkappa bypasses an abasic site and N-2-acetylaminofluorene (AAF)-adduct in an error-prone manner but does not bypass a cis-syn or (6-4) thymine-thymine dimer or a cisplatin-adduct. Therefore, our results implicate an important role for polkappa in the mutagenic bypass of certain types of DNA lesions. 相似文献
13.
Background: It is not well known how the immediate precursors of osteoclast develop into osteoclasts in the fetus. This ultrastructural-cytochemical study was designed to clarify the formation process of the osteoclasts and their increased activities in the fetal mouse limb buds after administration of high dose parathyroid hormone (PTH). Methods: Twenty-four or forty-eight hours after the high doses of PTH were injected into amniotic fluid of the pregnant C3H mice, the femoral limb buds of embryos were dissected out. Tartrate-resistant acid phosphatase (TRAP) reactions were performed while preparing specimens for electron microscopy. Results: Both control and PTH-given preosteoclasts and osteoclasts exhibited TRAP-positivities in dense bodies and vesicles. As effects of PTH, a binucleated preosteoclast of tandem fashion was observed. More osteoclastic hyperactivities were observed in the diaphyseal bone marrow. An osteoclast with a large cytoplasm exhibited two sets of clear zones and ruffled borders. Some osteoclasts demonstrated prominent amoeboid figures, while other osteoclasts developed large cytoplasmic vacuoles, which contained pieces of calcified chondroid bars. Conclusions: Our results revealed the progression of maturation from young preosteoclasts to osteoclasts. An existence of a peculiar binucleated preosteoclasts suggested one of the processes for multinucleation of the osteoclast. Quite remarkable osteoclastic hyperactivities were obviously the effects of high dose PTH. Our results also indicated the endophagocytic ability of the osteoclast. How PTH affected the osteoclasts and their precursors in the diaphyseal bone marrow can be speculated. © 1995 Wiley-Liss, Inc. 相似文献
14.
Summary Infection of BHK cells with western equine encephalitis (WEE) virus resulted in rapid inhibition of cellular DNA synthesis. The rate of inhibition of DNA synthesis depended on the multiplicity of infection, and was closely related to virus replication. Cellular DNA synthesis was not inhibited in infected BHK cells that had been irradiated with ultraviolet radiation. These results indicated that a functional viral genome was required for the inhibition of DNA synthesis by WEE virus. The sharp decrease in thymidine incorporation into the acid-insoluble fraction was not due to a change in the intracellular pool of the acid-soluble fraction. Sedimentation analysis in alkaline sucrose gradients was used to show that cellular DNA was not degraded during WEE virus infection. DNA polymerase activity in infected cells was not significantly reduced.With 4 Figures 相似文献
15.
Positive and negative selection events are involved in determining useful T cell clones to mature in the thymus. Accumulating evidence suggests that immature self-reactive thymocytes undergo apoptotic death (negative selection) upon stimulation via the T cell receptors (TcR). A similar phenomenon of activation-induced death has been reported in T cell hybridomas. On the other hand, little is known about the mechanism of the positive selection. Apoptosis in rodent thymocytes or T cell hybridomas is also known to be induced by glucocorticoids in vitro at concentrations within the physiologic range. We report here that the TcR/CD3-mediated stimulation and glucocorticoids mutually inhibit the apoptosis in T cell hybridomas. The production of interleukin 2 by the rescued cells indicated that the TcR/CD3-mediated signal was transduced into the cells. Thymocytes were also rescued from glucocorticoid-induced apoptosis by the stimulation with antibodies to TcR/CD3 molecules. The rescue of thymocytes, however, was observed only at a narrow concentration range of each of the antibodies, suggesting that the proper stimulation via the TcR/CD3 is required for the rescue. If thymocytes in situ are differentially stimulated according to the affinity of the TcR towards self, only the thymocytes whose TcR have proper affinity towards self may be rescued from glucocorticoid-induced apoptosis. Therefore, we propose a hypothesis that the positive selection of the T cell repertoire is based on the inhibition of glucocorticoid-induced apoptosis in immature thymocytes bearing TcR with proper affinity for self by the TcR-mediated signals in situ. Furthermore, the selection may be influenced by the peak level of glucocorticoid concentration, since the proper concentration range of the anti-TcR/CD3 antibody for the rescue was variable depending on the glucocorticoid concentration. 相似文献
16.
Obuse C Yang H Nozaki N Goto S Okazaki T Yoda K 《Genes to cells : devoted to molecular & cellular mechanisms》2004,9(2):105-120
CENP-A, a centromere-specific histone H3, is conserved throughout eukaryotes, and formation of CENP-A chromatin defines the active centromere region. Here, we report the isolation of CENP-A chromatin from HeLa interphase nuclei by chromatin immunoprecipitation using anti-CENP-A monoclonal antibody, and systematic identification of its components by mass spectrometric analyses. The isolated chromatin contained CENP-B, CENP-C, CENP-H, CENP-I/hMis 6 and hMis 12 as well as CENP-A, suggesting that the isolated chromatin may represent the centromere complex (CEN-complex). Mass spectrometric analyses of the CEN-complex identified approximately 40 proteins, including the previously reported centromere proteins and the proteins of unknown function. In addition, we unexpectedly identified a series of proteins previously reported to be related to functions other than chromosome segregation, such as uvDDB-1, XAP8, hSNF2H, FACTp180, FACTp80/SSRP1, polycomb group proteins (BMI-1, RING1, RNF2, HPC3 and PHP2), KNL5 and racGAP. We found that uvDDB-1 was actually localized to the centromeric region throughout cell cycle, while BMI-1 was transiently co-localized with the centromeres in interphase. These results give us new insights into the architecture, dynamics and function of centromeric chromatin in interphase nuclei, which might reflect regulation of cell proliferation and differentiation. 相似文献
17.
Chinzei M Chinzei T Yonezawa T Lee CS Tagami M Hanaoka K Imachi K 《Masui. The Japanese journal of anesthesiology》1999,48(1):9-17
We aimed to develop a method of accurately identifying the dorsal root for the corresponding peripheral afferent nerve under endoscopic observation. We developed an endoscope with an external diameter of 1.8 mm. After small laminectomy on the lower thoracic vertebrae, we inserted this endoscope carefully into the epidural and then subarachnoid spaces. We observed structures in these spaces with the endoscope. We tried to determine the spatial relationship between these electrodes and dorsal root. After identifying each space, we inserted two electrodes into the visualized space to record evoked potentials; a bipolar electrode (protocol 1) and a catheter-type eight polar electrode (protocol 2). Each pole could be distinguished by marks. To stimulate peripheral nerves, we inserted needle-type electrodes into Th 10, 11 and 12 intercostal nerves. We attempted to record potentials from dorsal surface of the cord generated by intercostal nerve stimulus. Protocol 1: We moved the position of the bipolar recording electrodes between Th 9 and L 1 by 1 cm increment, and obtained evoked potentials correspondingly. Protocol 2: We chose the neighboring pairs of poles sequentially from the tip of the catheter for bipolar recording. At the end of each experiment, we dissected the animal and checked the intercostal nerve originating from the root. With the endoscope, we could clearly observe structures in the epidural and subarachnoid spaces. We could record evoked potentials from the dorsal spinal cord with the electrodes located either in epidural or in subarachnoid spaces. Shapes of evoked potentials changed characteristically according to the relative position between the root and the electrode. The largest potentials were obtained when the electrode was nearest to the dorsal root, of which the peripheral nerve was being stimulated. By combining endoscopy with the electrophysiological technique, we could accurately identify the dorsal roots for the corresponding peripheral afferent nerves. This method may be used for the selective dorsal root blockade under the visual field. 相似文献
18.
Orii R Sugawara Y Hayashida M Yamada Y Kubota K Takayama T Harihara Y Makuuchi M Hanaoka K 《Transplantation》2000,69(10):2124-2127
BACKGROUND: The role of changes in peri-operative blood lactate levels in recipients of living-related liver transplants has not yet been clarified. METHODS: Forty-three recipients were included in this study. Blood lactate, plasma total bilirubin, aminotransferase, body temperature, and gastric mucosal PCO2 levels were measured at six time points during surgery: just before the initiation of surgery, just after dissection of the hepatic vasculature, at the end of the anhepatic phase, and 30, 60, and 120 min after reperfusion. We calculated the rate of lactate accumulation during the pre-anhepatic and anhepatic phases and the elimination rate during reperfusion (neohepatic phase), and examined the correlation between these results and the clinical findings. RESULTS: The rate of lactate elimination during the neohepatic phase was correlated with the ratio of graft weight to standard liver volume (P<0.0001). There was also a significant correlation between the rate of lactate accumulation during the pre-anhepatic phase and the preoperative total bilirubin levels (P=0.0008). CONCLUSIONS: Each pre-anhepatic, anhepatic, and neohepatic phase had a characteristic blood lactate profile. The graft size strongly affected lactate levels during the early neohepatic phase. 相似文献
19.
Tetsuya Otani Motoki Iwasaki Seiichiro Yamamoto Tomotaka Sobue Tomoyuki Hanaoka Manami Inoue Shoichiro Tsugane 《Cancer epidemiology, biomarkers & prevention》2003,12(12):1492-1500
Few studies have examined the association of alcohol consumption and cigarette smoking with colorectal cancer in Asian populations whose genetic susceptibility to these factors are different from Western populations. We investigated this association and the joint effect of these factors, and estimated the population-attributable fraction to clarify the public health impact on a Japanese population, based on a prospective study. We analyzed the 10-year (cohort I) and 7-year (cohort II) follow-up data of the Japan Public Health Center-based prospective study on cancer and cardiovascular disease, derived from 90,004 (42,540 male and 47,464 female) middle-aged and elderly Japanese. We identified 716 (457 in men and 259 in women) newly diagnosed cases of colorectal cancer. Both alcohol consumption and smoking were clearly associated with colorectal cancer in men, after adjusting for age, family history of colorectal cancer, body mass index, and physical exercise. Regular heavy drinking of 150 g/week or more of ethanol showed a statistically significant increased risk compared with nondrinkers: relative risks (RRs) were 1.4 [95% confidence interval (CI), 1.1-1.9] for 150-299 g/week and 2.1 (95% CI, 1.6-2.7) for 300 g/week or more. On the contrary, regular ethanol consumption was not associated with colorectal cancer (RR, 0.7; 95% CI, 0.4-1.1) in women. In terms of smoking, the RRs were 1.4 (95% CI, 1.1-1.8) for current smokers and 1.3 (95% CI, 0.98-1.7) for ex-smokers compared with never-smokers in men. The risk of smoking in women was similar to that in men, although not statistically significant. The colorectal cancer risk with 300 g/week or more of ethanol in current smokers was estimated at 3.0 (95% CI, 1.8-5.1) compared with nondrinkers among nonsmokers in men. Colorectal cancer attributable to alcohol consumption or smoking was estimated to be 46%. In conclusion, approximately half of the colorectal cancer cases may be preventable by tobacco and alcohol controls in middle-aged and elderly Japanese men. 相似文献
20.
A 71-year-old male with cervical myelopathy was scheduled for C 3-7 laminectomy. Once he had been rejected of general anesthesia in other hospital because of his tracheal stenosis. The diameter of the narrowest part of his trachea was 5 mm probably resulting from tracheostomy at 2 years of age. His cervical myelopathy seemed to be no problem for anesthesia induction because he had no problems in his neck movement and opening mouth. We evaluated his tracheal stenosis carefully using bronchofiberscopy, chest X-ray, computed tomography and pulmonary function tests. After intravenous fentanyl 100 micrograms and midazolam 2.5 mg, it was impossible to ventilate the patient. Therefore, tracheal intubation was performed immediately after lidocaine administration into the trachea. During surgery, tracheal tube dilated the narrowed portion. After surgery, the tracheal tube was removed under bronchofiberscopic observation without any problems. Tracheal stenosis was observed by chest X-ray after surgery, but he had no complaints. 相似文献