全文获取类型
收费全文 | 1335913篇 |
免费 | 95879篇 |
国内免费 | 5040篇 |
专业分类
耳鼻咽喉 | 17699篇 |
儿科学 | 41515篇 |
妇产科学 | 37375篇 |
基础医学 | 191806篇 |
口腔科学 | 38614篇 |
临床医学 | 117202篇 |
内科学 | 263213篇 |
皮肤病学 | 30396篇 |
神经病学 | 103502篇 |
特种医学 | 50861篇 |
外国民族医学 | 378篇 |
外科学 | 203949篇 |
综合类 | 32422篇 |
现状与发展 | 1篇 |
一般理论 | 446篇 |
预防医学 | 93185篇 |
眼科学 | 31117篇 |
药学 | 99805篇 |
4篇 | |
中国医学 | 4009篇 |
肿瘤学 | 79333篇 |
出版年
2018年 | 14382篇 |
2017年 | 11093篇 |
2016年 | 12339篇 |
2015年 | 13943篇 |
2014年 | 19219篇 |
2013年 | 28268篇 |
2012年 | 37481篇 |
2011年 | 39478篇 |
2010年 | 23728篇 |
2009年 | 22396篇 |
2008年 | 36910篇 |
2007年 | 39370篇 |
2006年 | 39693篇 |
2005年 | 37739篇 |
2004年 | 36556篇 |
2003年 | 35249篇 |
2002年 | 33937篇 |
2001年 | 71754篇 |
2000年 | 73516篇 |
1999年 | 61217篇 |
1998年 | 15789篇 |
1997年 | 13820篇 |
1996年 | 13541篇 |
1995年 | 12821篇 |
1994年 | 11847篇 |
1993年 | 10955篇 |
1992年 | 46789篇 |
1991年 | 44947篇 |
1990年 | 43937篇 |
1989年 | 42741篇 |
1988年 | 38727篇 |
1987年 | 38415篇 |
1986年 | 35634篇 |
1985年 | 34123篇 |
1984年 | 24778篇 |
1983年 | 20649篇 |
1982年 | 11727篇 |
1981年 | 10378篇 |
1979年 | 21962篇 |
1978年 | 15329篇 |
1977年 | 13064篇 |
1976年 | 11836篇 |
1975年 | 12637篇 |
1974年 | 15175篇 |
1973年 | 14515篇 |
1972年 | 13527篇 |
1971年 | 12728篇 |
1970年 | 11754篇 |
1969年 | 11145篇 |
1968年 | 10251篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
M.B. McDermott A.C. Lind E.F. Marley L.P. Dehner 《Pediatric and developmental pathology》1998,1(4):300-308
Deep granuloma annulare (DGA) is one of several lesions of skin and superficial soft tissues whose histologic character is
a palisading granuloma with a small central focus of necrosis or necrobiosis. Unlike the other palisading necrobiotic lesions,
DGA has a predilection for children in the first 5 to 6 years of life. A painless subcutaneous nodule(s) in the lower anterior
tibial region or foot and the scalp, typically in the occiput, was the most common presenting feature in this study of 35
cases. Additional or recurrent lesions were reported in approximately 70% of cases with clinical follow-up. All lesions showed
the presence of necrobiosis; however, one of the characteristic features was the multinodular character of the predominantly
mononuclear cellular aggregates. The presence of vascular spaces at the periphery of the nodular profiles served as a clue
to the diagnosis of DGA. The palisading arrangement of the mononuclear cells was evident only in those foci with central necrobiosis.
A histiocytic disorder or fibrohistiocytic process was a common consideration in the differential diagnosis, especially in
those cases with less apparent foci of necrosis. Palisading histiocytes with prominent eosinophilic cytoplasm and some nuclear
atypism were problematic with regard to possible epithelioid sarcoma. Our study failed to identify any underlying or predisposing
factors in the development of DGA. Despite the fact that DGA is a well-documented lesion in children, it occurs sufficiently
infrequently that it is often not considered clinically when it presents as a subcutaneous mass or masses in a child. Its
recognition by the pathologist is especially important as the occurrence of additional lesions in a high proportion of children
can be anticipated without undue concern.
Received June 16, 1997; accepted October 28, 1997. 相似文献
992.
Wolfgang B. Fischer Petra Ptschke Giesela Pompe Klaus-Jochen Eichhorn Heinz W. Siesler 《Macromolecular chemistry and physics.》1997,198(7):2057-2072
Rheo-optical Fourier transform infrared spectroscopy was used to analyze the orientational behavior of hard and soft segments of thermoplastic poly(ether urethane)s (TPU-Et) and poly(ester urethane)s (TPU-Es) and their blends with a 20 mass-% contribution of either polyethylene (PE) or polypropylene with an amorphous rubber phase (PP). The blends show a reduced stress level, lower elongation-to-break and a lower degree of orientation of the segments — especially for the TPU-Es blends — compared to those of pure TPU's when uniaxially elongated. Blends of TPU-Et with PP show reduced stress but increased strain compared to pure films of TPU-Et. This is caused by an improved adhesion of the rubber phase in the polypropylene and the polyether phase of TPU-Et. Optical micrographs visualize deformed polyolefin particles in elongated films of TPU-Et/PP blends. In the TPU-Et/PP blend we could achieve equivalent orientation for the polyolefin phase and the segments of TPU-Et caused by this higher phase adhesion compared to the other blends. Orientation functions (OF's) of absorption bands which specifically represent hard or soft polyurethane segments or which are characteristic of the polyolefin phase have been calculated to monitor the molecular alignment due to the mechanical treatment. 相似文献
993.
Vivian E. von Gruenigen M.D. Joseph T. Santoso M.D. Robert L. Coleman M.D. Carolyn Y. Muller M.D. David Scott Miller M.D. J.Michael Mathis Ph.D. 《Gynecologic oncology》1998,69(3):197-204
Objectives.To test the safety, efficacy, and toxicity of gene therapy using wild-type p53-expressing adenovirus (Ad-CMV-p53) in a nude mouse model with intraperitoneal (ip) 2774 human ovarian cancer cell line that contains a p53 mutation.Study design.An initial study of adenovirus tolerance was determined in nude mice by a single ip injection of increasing doses of Ad-CMV-p53. Nude mice were implanted with an LD100dose of 1 × 107cells. To study the efficacy and specificity of Ad-CMV-p53 treatment, the mice received treatment with different adenovirus constructs. One group received Ad-CMV-p53 and another group received a control adenovirus construct, Ad-CMV-βgal. To study the treatment response to Ad-CMV-p53, the mice were divided into groups and received various treatment schedules of 1 × 108pfu of Ad-CMV-p53.Results.The mice tolerated Ad-CMV-p53 without adverse effects at doses of 1 × 108pfu. The response to Ad-CMV-p53 showed significant survival duration in each dose regimen, with a survival time greater than that of untreated animals (P= 0.0173). However, no statistically significant survival advantage was observed between Ad-CMV-p53- and Ad-CMV-βgal-treated mice.Conclusions.These studies show that at the adenovirus dose and administration regimen used, there is effective but not specific 2774 tumor growth inhibitionin vivo.Efficient introduction of biologically active genes into tumor cells would greatly facilitate cancer therapy. Thus, although promising, these results caution that much effort will be required to realize the potential for clinical application of adenovirus-based ovarian cancer gene therapy. 相似文献
994.
Norethisterone enanthate (NET-En), an established intramuscular long-acting contraceptive agent, has previously been shown to be effective in inhibiting fertility in two rodent species even 4 days after oral ingestion. Pharmacokinetics of NET and NET-En were studied after oral and intramuscular doses in two animal species and a few women. The results suggest that the NET-En was absorbed within a day in all the species after oral dose. The estimates of relative bioavailability ranged from 13 to 51% in rabbits, monkeys, and women. The elimination half-life was 5–10 days. The presence of the active component, NET, in the circulation over the experimental period of 15 days suggests that NET-En could be useful as a long-acting oral pill. The suppression of progesterone levels during the luteal phase of menstrual cycle in women also supports this finding. 相似文献
995.
996.
997.
998.
999.
M. Emoto H. Iwasaki K. Oshima M. Kikuchi Y. Kaneko T. Kawarabayashi 《Virchows Archiv : an international journal of pathology》1997,431(4):249-256
Rhabdomyosarcoma (RMS) is occasionally found in the female genital tract, and mostly appears as one of the heterologous mesenchymal
components in uterine carcinosarcoma designated as malignant mixed müllerian tumour (MMMT). We examined the biological properties
of a pure rhabdomyosarcoma (RMS) cell line designated FU-MMT-3, which was newly established from a surgical specimen taken
from a patient with uterine MMMT. We also evaluated c-myc and MYCN gene amplification in three RMS cell lines (including FU-MMT-3) derived from three MMMTs by Southern blot analysis.
FU-MMT-3 cells were propagated continuously for 57 serial passages over a 2-year period in vitro. FU-MMT-3 was able to produce
tumours demonstrating pure RMS in athymic nude mice. Cytogenetically, FU-MMT-3 showed a triploidy pattern, with complex karyotypic
abnormalities including trisomy of chromosome 8. All three RMS cell lines, including FU-MMT-3, showed amplification of the
c-myc gene (approximately fourfold to eightfold), while no cell lines demonstrated MYCN gene amplification. FU-MMT-3 is considered
to provide a useful system for the study of the biological behaviour of RMS in MMMTs. Extra copies of chromosome 8 and c-myc gene amplification may be associated with the rhabdomyoblastic differentiation in MMMT.
Received: 7 January 1997 / Accepted: 2 May 1997 相似文献
1000.