全文获取类型
收费全文 | 2459篇 |
免费 | 109篇 |
国内免费 | 12篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 56篇 |
妇产科学 | 10篇 |
基础医学 | 354篇 |
口腔科学 | 61篇 |
临床医学 | 130篇 |
内科学 | 634篇 |
皮肤病学 | 7篇 |
神经病学 | 109篇 |
特种医学 | 138篇 |
外科学 | 362篇 |
综合类 | 6篇 |
预防医学 | 57篇 |
眼科学 | 63篇 |
药学 | 239篇 |
中国医学 | 5篇 |
肿瘤学 | 346篇 |
出版年
2023年 | 13篇 |
2022年 | 11篇 |
2021年 | 34篇 |
2020年 | 21篇 |
2019年 | 32篇 |
2018年 | 39篇 |
2017年 | 24篇 |
2016年 | 38篇 |
2015年 | 50篇 |
2014年 | 58篇 |
2013年 | 81篇 |
2012年 | 127篇 |
2011年 | 116篇 |
2010年 | 99篇 |
2009年 | 54篇 |
2008年 | 110篇 |
2007年 | 123篇 |
2006年 | 138篇 |
2005年 | 169篇 |
2004年 | 184篇 |
2003年 | 142篇 |
2002年 | 176篇 |
2001年 | 70篇 |
2000年 | 55篇 |
1999年 | 65篇 |
1998年 | 36篇 |
1997年 | 27篇 |
1996年 | 32篇 |
1995年 | 32篇 |
1994年 | 28篇 |
1993年 | 35篇 |
1992年 | 37篇 |
1991年 | 24篇 |
1990年 | 26篇 |
1989年 | 39篇 |
1988年 | 30篇 |
1987年 | 27篇 |
1986年 | 27篇 |
1985年 | 24篇 |
1984年 | 16篇 |
1983年 | 17篇 |
1982年 | 7篇 |
1981年 | 11篇 |
1980年 | 17篇 |
1979年 | 8篇 |
1978年 | 9篇 |
1976年 | 6篇 |
1975年 | 5篇 |
1974年 | 5篇 |
1973年 | 5篇 |
排序方式: 共有2580条查询结果,搜索用时 46 毫秒
1.
2.
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
3.
4.
5.
H Ito N Shigematsu I Nishiguchi T Kuribayashi K Toya S Hashimoto 《Nihon Igaku Hōshasen Gakkai zasshi. Nippon acta radiologica》1992,52(6):830-837
This study was carried out to determine the effect of irradiation of a tumor on the development of lung metastases. SANH, a spontaneous sarcoma, was isotransplanted in the right thighs of C3H mice which were either locally preirradiated (30 Gy: TBR) or non-irradiated. When the tumors had grown to 7 mm in diameter, they received 20-30 Gy of electron beams (RTx). The tumor-bearing legs were amputated at various tumor sizes, and the incidence of metastasis and number of lung nodules were compared in each treatment group. The incidences of metastases from 7 mm tumors in mice with regrowing tumors after RTx (30 Gy) and non-irradiated mice were 28% and 4%, respectively. When tumors grown in preirradiated legs were removed at 7 mm in diameter, the incidence of metastases (58%) was also enhanced by preirradiation of the tumor bed. Seven millimeter tumors that were growing in TBR legs and received RTx (20 Gy) developed a higher incidence (82%) and greater numbers of metastases than either the RTx or TBR groups. To determine the relationship between the interval of tumor bearing and development of metastases, tumors were removed at various intervals after tumor transplantation in 4 groups, namely, non-irradiated, TBR, RTx and TBR with 20 GyRTx. Lung metastases came later but increased steeply in mice given either TBR or RTx, compared with non-irradiated mice. Tumors growing in TBR and receiving RTx (20 Gy) developed many more metastases than any other group.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
6.
T. Terada K. Miyamoto G. Hyotani M. Tsuura Y. Nakamura T. Nishiguchi T. Itakura S. Hayashi N. Komai 《Acta neurochirurgica》1992,118(3-4):108-111
Summary Changes in tumour blood flow under an induced hypertensive state were examined in malignant brain tumours to know if the precondition for the effectiveness of induced hypertensive chemotherapy — relative increase in tumour blood flow — are fulfilled. Tumour blood flow was measured under both a resting and an induced hypertensive state in 12 patients with various malignant brain tumours (6 gliomas, 6 metastatic brain tumours) using xenon-enhanced computed tomography. The blood pressure was elevated 40% above the systemic blood pressure of the resting state by the infusion of angiotensin II. Tumour blood flow increased 30% on average above the normal brain tissue blood flow after the induction of an induced hypertensive state (p < 0.05). The tumour blood flow increased in 11 cases of malignant tumours, but decreased in one case with massive brain oedema after induced hypertension. The increase in blood flow was higher in hypervascular tumours and less in hypovascular tumours. Therefore, induced hypertensive chemotherapy probably will be more effective in hypervascular malignant brain tumours with small mass effects. 相似文献
7.
8.
Eduardo Kazuo Sannomiya Jun-ichi Asaumi Kanji Kishi Gisele da Silva Dalben 《Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics》2007,104(2):e41-e44
Dens invaginatus is a developmental variation resulting from an alteration in the normal growth pattern of the dental papilla. Synonyms of this disturbance include dens in dente, invaginated odontome, tooth inclusion, and dentoid in dente. Radiographically, it is observed as infolding of a radiopaque ribbon-like structure, with equal density as enamel, extending from the cingulum into the root canal and sometimes reaching the root apex, assigning the appearance of a small tooth within the coronal pulp cavity. This article presents 2 case reports. The first describes an 8-year-old girl with dens invaginatus in a mesiodens; the second report describes a 16-year-old boy presenting with 2 mesiodens, both associated with dens invaginatus. 相似文献
9.
Takahiko Misao Kanji Minamoto Hideharu Nakano Masataka Yamane Yosuke Yamamoto Katashi Satoh 《General thoracic and cardiovascular surgery》2005,53(6):309-312
A 64-year-old female was found to have localized ground-glass opacity (GGO) in the middle lobe on a chest computed tomography (CT) for screening. Middle lobectomy with video-assisted thoracoscopic surgery (VATS) was undertaken, and pathological diagnosis was a bronchioloalveolar carcinoma (BAC) in stage IA. A follow-up CT a year following the surgery revealed localized GGO in area S6 of the left lung. However, it disappeared during the gravitation-dependent gradient in the observation period. The patient was scanned again under prone position to exclude the gravitational effect, resulting in definite detection of the GGO. Left extended S6 segmentectomy with VATS was performed, and pathological diagnosis was a BAC in stage IA. As GGO existing in a gravitation-dependent area may be masked by the gravitation-dependent density, a change of the scanning position may lead to a proper detection of the tumor for the diagnosis of BAC. 相似文献
10.