全文获取类型
收费全文 | 13000篇 |
免费 | 620篇 |
国内免费 | 68篇 |
专业分类
耳鼻咽喉 | 92篇 |
儿科学 | 217篇 |
妇产科学 | 146篇 |
基础医学 | 1805篇 |
口腔科学 | 238篇 |
临床医学 | 817篇 |
内科学 | 3318篇 |
皮肤病学 | 193篇 |
神经病学 | 1101篇 |
特种医学 | 729篇 |
外科学 | 1817篇 |
综合类 | 34篇 |
预防医学 | 426篇 |
眼科学 | 163篇 |
药学 | 1083篇 |
中国医学 | 33篇 |
肿瘤学 | 1476篇 |
出版年
2023年 | 67篇 |
2022年 | 103篇 |
2021年 | 191篇 |
2020年 | 106篇 |
2019年 | 109篇 |
2018年 | 148篇 |
2017年 | 121篇 |
2016年 | 183篇 |
2015年 | 206篇 |
2014年 | 230篇 |
2013年 | 291篇 |
2012年 | 514篇 |
2011年 | 553篇 |
2010年 | 343篇 |
2009年 | 284篇 |
2008年 | 523篇 |
2007年 | 597篇 |
2006年 | 597篇 |
2005年 | 605篇 |
2004年 | 644篇 |
2003年 | 641篇 |
2002年 | 728篇 |
2001年 | 519篇 |
2000年 | 531篇 |
1999年 | 474篇 |
1998年 | 224篇 |
1997年 | 171篇 |
1996年 | 187篇 |
1995年 | 160篇 |
1994年 | 115篇 |
1993年 | 106篇 |
1992年 | 402篇 |
1991年 | 331篇 |
1990年 | 299篇 |
1989年 | 358篇 |
1988年 | 285篇 |
1987年 | 295篇 |
1986年 | 234篇 |
1985年 | 197篇 |
1984年 | 169篇 |
1983年 | 111篇 |
1982年 | 86篇 |
1981年 | 74篇 |
1980年 | 67篇 |
1979年 | 108篇 |
1978年 | 74篇 |
1977年 | 67篇 |
1976年 | 43篇 |
1975年 | 32篇 |
1974年 | 21篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Kanji Takeo Eric Virtudazo Misako Ohkusu Susumu Kawamoto Shoko Ito-Kuwa Sigeji Aoki 《Nippon Ishinkin Gakkai Zasshi》2006,47(4):257-262
In Cryptococcus neoformans the DNA content of cells having tiny buds varied rather widely, depending on growth phases and strains used. Typically, buds of C. neoformans emerged soon after initiation of DNA synthesis in the early exponential phase. However, bud emergence was delayed to G2 during transition to the stationary phase, and in the early stationary phase budding scarcely occurred, although roughly half of the cells completed DNA synthesis. The timing of budding in C. neoformans was shifted to later cell cycle points with progression of the growth phase of the culture. Similarly, a deficit in oxygen was demonstrated to delay the timing of budding, prolong the G2 phase and cause accumulation of cells after DNA synthesis, but before commitment to budding. The C. neoformans homologue of the main cell cycle control gene CDC28/Cdc2 was isolated using degenerate RT-PCR. The full-length coding region was then amplified using primers to target the regions around the start and stop codons. The gene was called CnCdk1 and was found to have high homologies to S. cerevisiae CDC28 and S. pombe cdc2. To determine its function, its ability to rescue S. cerevisiae cdc28-temperature sensitive mutants was tested. S. cerevisiae cdc28-4 and cdc28-1N strains transformed with the pYES2-CnCdk1 construct exhibited growth at the restrictive temperature. Results of the sequence analysis and the ability of CnCdk1 to complement the S. cerevisiae cdc28-ts mutations support its assumed role as the CDC28/cdc2 homologue in C. neoformans. 相似文献
2.
M Nakanishi Y Demura S Mizuno S Ameshima Y Chiba I Miyamori H Itoh M Kitaichi T Ishizaki 《The European respiratory journal》2007,29(3):453-461
High-resolution computed tomography (HRCT) findings in patients with respiratory bronchiolitis-associated interstitial lung disease (RB-ILD) are varied and nonspecific. There is no known report of changes in HRCT findings and respiratory function test results for RB-ILD patients following the cessation of smoking. Five patients with RB-ILD, confirmed by surgical lung biopsy, were retrospectively studied. Each stopped cigarette smoking and did not receive corticosteroid therapy after diagnosis. The clinical symptoms, respiratory function test results and HRCT findings obtained at the final observation were compared with those from the time of diagnosis. Ground-glass opacity and centrilobular nodules corresponding to pathological respiratory bronchiolitis, as well as intralobular fine linear-reticular opacity corresponding to fibrosis involving the subpleural alveolar septa, showed computed tomography-pathological correlations. Both clinical symptoms and the diffusing capacity of the lungs for carbon monoxide improved significantly following smoking cessation, as did ground-glass opacity and centrilobular nodules seen during the initial HRCT examination. Centrilobular nodules and ground-glass opacity, which are the main features of high-resolution computed tomography of respiratory bronchiolitis-associated interstitial lung disease patients and represent pathological respiratory bronchiolitis, can be improved by smoking cessation. The diffusing capacity of the lung for carbon monoxide in respiratory function tests can be also improved. 相似文献
3.
T Kato M Itoh J Hanashita T Itoi T Matsumoto Y Ono S Imamura N Hayakawa A Suzuki Y Mizutani Y Uchigata N Oda 《Diabetic medicine》2007,24(11):1279-1281
AIMS: A rare case of the insulin autoimmune syndrome (IAS) accompanied by insulin receptor anomaly is reported. METHODS: Antibodies to insulin and insulin receptor were determined in the patient with severe hypoglycaemia before and after the treatment with prednisolone. RESULTS: Titers of antibody to insulin and insulin receptors were 73.0% and 41.5%, respectively. Drug-induced lymphocyte stimulation tests were all negative for the suspicious drugs. Her HLA-DR was DRB1*0403/04051. Following steroid therapy, the formation of antibodies was suppressed and alleviated her symptoms. Scatchard analysis yielded findings specific to polyclonal antibodies. CONCLUSIONS: The changes in autoantibodies resulted in alleviation of the hypoglycemic symptoms as a result of steroid therapy. 相似文献
4.
5.
K Itoh K Nishimura K Togashi I Fujisawa Y Nakano H Itoh K Torizuka 《Journal of computer assisted tomography》1986,10(5):831-835
Four patients with cavernous hemangioma of face and neck were evaluated with magnetic resonance imaging. Pathologically, soft tissue cavernous hemangiomas are characterized by small feeding arteries and large blood poolings. Arteriography usually fails to demonstrate the extent of the lesion. Computed tomography does not allow differentiation between these lesions and surrounding normal tissues. Magnetic resonance clearly demonstrates hemangiomas with good contrast between lesion and normal tissues. Spin-echo technique with long echo time appears to be particularly useful to delineate these lesions. 相似文献
6.
Hiroyuki Yamamoto Fumio Itoh Akinori Senota Yasushi Adachi Mitsuru Yoshimoto Takao Endoh Yuji Hinoda Akira Yachi Kohzoh Imai 《Journal of clinical laboratory analysis》1995,9(5):297-301
The matrix metalloproteinase matrilysin (MMP-7) is a member of the matrix metallo-proteinase gene family, which is believed to play an important role in tumor invasion and metastasis. We have previously found that matrilysin mRNA is specifically expressed in colorectal cancers and adenomas and that its message is localized in the tumor cells themselves. We examined the effects of activated Ki-ras oncogene on the expression of matrilysin in colon cancer cells. We showed that both mRNA and the enzymatic activity of matrilysin were induced by the introduction of activated Ki-ras into SW1417 colon cancer cells. To understand the mechanisms regulating this induction, we analyzed alterations of AP-1 activity induced by activated Ki-ras, using the chloramphenicol acetyltransferase assay. AP-1 activity in SW1417 cells expressing activated Ki-ras was higher than that in control cells. The gel-shift assay also showed higher levels of AP-1 binding protein in SW1417 cells expressing activated Ki-ras than those in control cells. Our results suggest that activated Ki-ras may play a role in inducing expression of matrilysin through an AP-1-dependent pathway in colon cancer cells. 相似文献
7.
Changes in the levels of urea cycle enzymes and polyamine metabolism in the liver of rats treated with alpha-naphthylisothiocyanate (ANIT), an inducer of experimental cholestasis, were studied. Activities of arginase increased approximately two-fold compared to the control values during the period of 24-72 hours after oral administration of ANIT (100 mg/kg), while activities of ornithine carbamyltransferase and ornithine aminotransferase decreased. The activity of ornithine decarboxylase was elevated by approximately 20- and 10-fold at 12 and 60 hours, respectively, after ANIT administration. Putrescine concentration doubled 24-48 hours after the ANIT administration, but spermidine level rose more slowly and reached the level of 1.5-fold of the control level in 36-72 hours. Spermine concentration decreased initially but increased in 96 hours. These results suggest that the increased activity of urea cycle accounts for the increase in the ornithine content and that the putrescine and spermidine acts as the initiator of recovery of the liver damaged by ANIT treatment. 相似文献
8.
H. Kitamura T. Shioiri M. Itoh Y. Sato K. Shichiri & T. Someya 《Journal of intellectual disability research : JIDR》2007,51(10):812-820
Background Evidence suggests that, as a group, patients with schizophrenia have intellectual deficits that may precede the manifestation of psychotic symptoms; however, how successfully intelligence tests are able to discriminate schizophrenia from other psychotic disorders has yet to be investigated in detail. Methods Using Wechsler Adult Intelligence Scale – Revised (WAIS‐R) data for 55 inpatients with schizophrenia and 28 inpatients with non‐schizophrenic psychotic disorders (NSPD) (schizophreniform disorder, brief psychotic disorder, delusional disorder, psychotic disorder due to a general medical condition, and psychotic disorders not otherwise specified), intelligence performance was compared between schizophrenia and NSPD and among different subtypes of schizophrenia. Results There were no significant differences in intelligence quotient (IQ), verbal IQ (VIQ) and performance IQ (PIQ) discrepancy, and subtest scores of WAIS‐R between the patients with schizophrenia and those with NSPD. These diagnostic groups were not discriminated well by any WAIS‐R variables. Schizophrenia patients with prominent negative symptoms, on the other hand, had a significantly larger IQ discrepancy (VIQ > PIQ) than those without prominent negative symptoms and NSPD patients. Intelligence performance in schizophrenia did not differ with respect to diagnostic subtypes and longitudinal courses. Conclusions The current study failed to show diagnostic usefulness of WAIS‐R in discriminating schizophrenia and other psychoses. A diagnosis of schizophrenia does not significantly impact intellectual deficits in psychotic disorders. 相似文献
9.
M Itoh K Itoh S Taguchi C Hirofuji H Takeuchi A Ishihara 《Aviation, space, and environmental medicine》1992,63(7):583-587
The fiber type composition of the soleus muscle was investigated in male Sprague-Dawley rats exposed to hypobaric hypoxia of 460 mm Hg from 5 to 12 weeks of age. The muscle fibers were classified as fast-twitch oxidative (FO) and slow-twitch (S) on the basis of adenosine triphosphatase (ATPase) and succinate dehydrogenase (SDH) reactions. Intermediate fibers (INT) with intermediate ATPase and high SDH reaction intensities were also examined. A type shift of muscle fibers from FO to INT and S was found in the control group during development. After exposure to hypoxia, the hypoxia group had a significantly greater percentage of FO fibers than the age-matched control group. There was no significant change in the total number of fibers in the muscle during development and after exposure to hypoxia. These results indicate that the increased percentage of FO fibers found in the developing rat under hypoxic conditions is due to a hypoxia-induced inhibition of the type shift of muscle fibers from FO to S during development. 相似文献
10.
In order to clarify whether leg-cooling after supramaximal treadmill exercise will change lactate disappearance rate from venous blood, blood lactate, calf blood flow, and skin temperature were determined in cold application and non-cold application recovery. In the cooling experiments, both legs were cooled with ice packs for 23 min during recovery. The skin temperature was significantly lower in the cold application as compared with the non-cold application. However, no significant difference was found in the blood lactate and/or calf blood flow between cold and non-cold conditions. In addition, there was no significant difference in the slope of regression line (blood lactate/blood flow) between cold and non-cold applications. These results suggest that no significant difference in the blood lactate between cold and non-cold applications could be explained by the lack of difference in the blood flow between cold and non-cold applications. 相似文献