全文获取类型
收费全文 | 3057篇 |
免费 | 310篇 |
国内免费 | 20篇 |
专业分类
耳鼻咽喉 | 14篇 |
儿科学 | 100篇 |
妇产科学 | 123篇 |
基础医学 | 409篇 |
口腔科学 | 29篇 |
临床医学 | 251篇 |
内科学 | 604篇 |
皮肤病学 | 43篇 |
神经病学 | 244篇 |
特种医学 | 201篇 |
外科学 | 426篇 |
综合类 | 116篇 |
一般理论 | 3篇 |
预防医学 | 340篇 |
眼科学 | 86篇 |
药学 | 199篇 |
1篇 | |
中国医学 | 5篇 |
肿瘤学 | 193篇 |
出版年
2021年 | 37篇 |
2019年 | 40篇 |
2018年 | 36篇 |
2017年 | 42篇 |
2016年 | 41篇 |
2015年 | 43篇 |
2014年 | 54篇 |
2013年 | 87篇 |
2012年 | 139篇 |
2011年 | 110篇 |
2010年 | 69篇 |
2009年 | 86篇 |
2008年 | 119篇 |
2007年 | 106篇 |
2006年 | 114篇 |
2005年 | 90篇 |
2004年 | 90篇 |
2003年 | 98篇 |
2002年 | 95篇 |
2001年 | 100篇 |
2000年 | 81篇 |
1999年 | 82篇 |
1998年 | 44篇 |
1997年 | 58篇 |
1996年 | 53篇 |
1995年 | 45篇 |
1994年 | 45篇 |
1993年 | 46篇 |
1992年 | 88篇 |
1991年 | 78篇 |
1990年 | 68篇 |
1989年 | 85篇 |
1988年 | 82篇 |
1987年 | 88篇 |
1986年 | 91篇 |
1985年 | 80篇 |
1984年 | 54篇 |
1983年 | 48篇 |
1982年 | 34篇 |
1981年 | 39篇 |
1980年 | 21篇 |
1979年 | 41篇 |
1978年 | 38篇 |
1977年 | 31篇 |
1976年 | 23篇 |
1974年 | 26篇 |
1973年 | 32篇 |
1971年 | 24篇 |
1969年 | 22篇 |
1967年 | 27篇 |
排序方式: 共有3387条查询结果,搜索用时 15 毫秒
1.
2.
Yasmine Yousef Etienne St-Louis Robert Baird Emily R. Smith Elena Guadagno Dickens St-Vil Dan Poenaru 《Journal of pediatric surgery》2019,54(4):831-837
Background
The Lancet Commission on Global Surgery highlighted global surgical need but offered little insight into the specific surgical challenges of children in low-resource settings. Efforts to strengthen the quality of global pediatric surgical care have resulted in a proliferation of partnerships between low-and middle-income countries (LMICs) and high-income countries (HICs). Standardized tools able to reliably measure gaps in delivery and quality of care are important aids for these partnerships. We undertook a systematic review (SR) of capacity assessment tools (CATs) focused on needs assessment in pediatric surgery.Methods
A comprehensive search strategy of multiple electronic databases was conducted per PRISMA guidelines without linguistic or temporal restrictions. CATs were selected according to pre-defined inclusion criteria. Articles were assessed by two independent reviewers. Methodological quality of studies was appraised using the COSMIN checklist with 4-point scale.Results
The search strategy generated 16,641 original publications, of which three CATs were deemed eligible. Eligible tools were either excessively detailed or oversimplified. None used weighted scores to identify finer granularity between institutions. No CATs comprehensively included measures of resources, outcomes, accessibility/impact and training.Discussion
The results of this study identify the need for a CAT capable of objectively measuring key aspects of surgical capacity and performance in a weighted tool designed for pediatric surgical centers in LMICs.Type of Study
Systematic Review.Level of Evidence
II. 相似文献3.
BACKGROUND: Posterior spinal procedures through tubular exposures have been described. However, tubes restrain visibility and require co-axial instrument manipulation, increasing difficulty and potentially compromising surgical results. An independent-blade retractor system overcomes the obstacles of working through a tube and has been used to perform minimally-disruptive decompression and instrumented tranforaminal lumbar interbody fusion (TLIF). PURPOSE: To evaluate the advantages to patient recovery and surgical efficacy of this technique. METHODS/RESULTS: Retrospective review of technique employing a minimally-disruptive approach to decompression and transforaminal lumber interbody fusion (TLIF). CONCLUSIONS: Minimally-disruptive decompression and instrumented TLIF can be performed in a safe and effective manner using an independent-blade retractor system. Relative to traditional-open techniques, surgical goals can be accomplished, but with the benefits of minimally-disruptive surgery. 相似文献
4.
PADGEM (GMP140) is a component of Weibel-Palade bodies of human endothelial cells 总被引:65,自引:10,他引:55
PADGEM protein (PADGEM), also known as GMP140, is a platelet alpha- granule membrane protein that is translocated to the external membrane after platelet activation. Although the biosynthesis of this protein was originally thought to be confined to megakaryocytes, the synthesis of PADGEM in endothelial cells was recently demonstrated (McEver et al: Blood 70:1974a, 1987). We now describe the subcellular localization of this protein in endothelial cells. Immunofluorescence staining of permeabilized human umbilical vein endothelial cells with KC4, a well characterized monoclonal antibody to PADGEM, showed positively stained elongated structures similar in distribution and shape to Weibel-Palade bodies. Their identity as Weibel-Palade bodies was confirmed by double label immunofluorescence using KC4 and a polyclonal antiserum to von Willebrand factor (vWf), a protein known to be specifically stored in these organelles. All Weibel-Palade bodies were found to contain PADGEM. In contrast to strong perinuclear staining produced with anti- vWf antibodies, no significant perinuclear staining was obtained with KC4, indicating that relatively little PADGEM is present in the endoplasmic reticulum and in the Golgi apparatus. In endothelial cells treated with secretagogues that stimulate vWf release the elongated structures positive for PADGEM disappeared, further identifying these structures as Weibel-Palade bodies. This observation extends the parallels between Weibel-Palade bodies and alpha-granules and suggests a possible functional association between vWf and PADGEM. 相似文献
5.
6.
D G Omdal D E Baird B S Burton W W Goodhue Jr E M Giddens 《AJNR. American journal of neuroradiology》1997,18(5):977
We describe a myelolipoma of the thoracic spine in a patient with gradual and progressive myelopathy. MR imaging showed this predominately fatty lesion to be extradural in location. 相似文献
7.
Occurrence of the t(2;5)(p23;q35) in non-Hodgkin's lymphoma 总被引:9,自引:3,他引:6
Weisenburger DD; Gordon BG; Vose JM; Bast MA; Chan WC; Greiner TC; Anderson JR; Sanger WG 《Blood》1996,87(9):3860-3868
Primary CD30(Ki-1)-positive anaplastic large-cell lymphoma (ALCL) is considered by some to be a distinct clinicopathologic entity associated with the t(2;5) (p23;q35). However, the specificity of t(2;5) for ALCL has not been carefully studied. Therefore, we performed a detailed analysis of all cases of ALCL with abnormal cytogenetics results in the Nebraska Lymphoma Study Group registry, as well as all other cases of non-Hodgkin's lymphoma with t(2;5) in the registry. We found the t(2;5) in only five of 10 cases of ALCL, four of whom were young patients. However, we also found the t(2;5) in 11 other cases of nonanaplastic lymphoma, including eight children with typical peripheral T-cell lymphomas of various types. The t(2;5) was also found in three older adults with B-cell lymphomas of various types. Thus, the t(2;5) was not specific for CD30+ ALCL. However, t(2;5) may define a clinicopathologic entity in children and young adults characterized by variable morphologies with a T-cell or indeterminate phenotype, CD30-positivity, nodal disease with frequent extranodal involvement, advanced stage, and an excellent response to therapy, including bone marrow transplantation for relapsed disease. The clinical relevance of the t(2;5) in older patients requires further study. 相似文献
8.
Previous studies from this Laboratory have revealed few significant age-related changes in either hepatic microsomal cytochrome
P450 content or NADPH-cytochrome P450 reductase activity, prompting the suggestion that the nearly ubiquitous age-associated decline in the hepatic metabolism
of xenobiotics by the mixed-function oxidases is a result of alterations in the lipid matrix in which the macromolecular components
are organized. In order to examine this postulate, the membrane microenvironment surrounding hepatic microsomal cytochrome
P450 was enzymatically digested with snake venom phospholipase A2, and the kinetics of conversion of cytochrome P450 to cytochrome P420 determined for preparations obtained from rats of varying age. There were no significant differences in the kinetics of conversion
of cytochrome P450 to cytochrome P420, suggesting that there are no significant age-related changes in the lipid microenvironment immediately adjacent to cytochrome
P450. However, there was a slight difference, independent of age, in the rate of conversion of cytochrome P450 to cytochrome P420 between smooth and rough microsomes. The results are discussed in terms of general experimental approaches toward understanding
drug metabolism in senescent organisms. 相似文献
9.
As part of a detailed study of limb defects and associated patterns of congenital malformations, cases with lower limb deficiencies were analysed separately. We identified a total of 130 cases with deficiencies of the lower limbs without defects of the upper limbs. This gives an incidence of 1.07/10,000 livebirths, or 1/9,337 for this group of limb defects. Most common were femur deficiencies and deficiencies of the foot. A preponderance of males was found in the group of transverse defects of the leg (fibula/tibia deficiencies) and central axis deficiencies, while females had significantly more often longitudinal tibia defects and preaxial ray defects. © 1993 Wiley-Liss, Inc. 相似文献
10.
The morphologic subgroups of intraductal carcinoma in situ (DCIS) of the breast may be biologically different. Thirty-eight patients with comedo-type DCIS treated with local resection with or without radiotherapy are presented. Thirteen of 35 patients had a family history of breast cancer, with 11 patients having an affected first-degree relative. This is significantly increased over other series of breast cancer patients. Recurrence was ipsilateral in all patients and occurred at the site of the original disease. Recurrence occurred in 4 of 30 patients treated with local resection only and 2 of 8 treated with local resection plus radiotherapy. The length of mean follow-up was 39 months. Because of the paucity of studies, these results cannot be compared with others, but there does appear to be a significant incidence of local recurrence after resection for comedo-type DCIS. Immunohistochemical and oncogene studies as they relate to comedo-type DCIS are discussed. 相似文献