全文获取类型
收费全文 | 1903篇 |
免费 | 137篇 |
国内免费 | 27篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 148篇 |
妇产科学 | 15篇 |
基础医学 | 196篇 |
口腔科学 | 87篇 |
临床医学 | 184篇 |
内科学 | 431篇 |
皮肤病学 | 48篇 |
神经病学 | 73篇 |
特种医学 | 355篇 |
外科学 | 140篇 |
综合类 | 25篇 |
一般理论 | 1篇 |
预防医学 | 116篇 |
眼科学 | 17篇 |
药学 | 97篇 |
1篇 | |
中国医学 | 1篇 |
肿瘤学 | 124篇 |
出版年
2023年 | 5篇 |
2022年 | 8篇 |
2021年 | 19篇 |
2020年 | 13篇 |
2019年 | 18篇 |
2018年 | 26篇 |
2017年 | 20篇 |
2016年 | 34篇 |
2015年 | 41篇 |
2014年 | 34篇 |
2013年 | 59篇 |
2012年 | 38篇 |
2011年 | 36篇 |
2010年 | 48篇 |
2009年 | 90篇 |
2008年 | 40篇 |
2007年 | 62篇 |
2006年 | 52篇 |
2005年 | 56篇 |
2004年 | 39篇 |
2003年 | 53篇 |
2002年 | 41篇 |
2001年 | 39篇 |
2000年 | 36篇 |
1999年 | 44篇 |
1998年 | 107篇 |
1997年 | 123篇 |
1996年 | 116篇 |
1995年 | 83篇 |
1994年 | 85篇 |
1993年 | 105篇 |
1992年 | 32篇 |
1991年 | 25篇 |
1990年 | 28篇 |
1989年 | 48篇 |
1988年 | 52篇 |
1987年 | 35篇 |
1986年 | 39篇 |
1985年 | 42篇 |
1984年 | 17篇 |
1983年 | 18篇 |
1982年 | 19篇 |
1981年 | 34篇 |
1980年 | 20篇 |
1979年 | 10篇 |
1978年 | 9篇 |
1977年 | 27篇 |
1976年 | 19篇 |
1975年 | 8篇 |
1969年 | 4篇 |
排序方式: 共有2067条查询结果,搜索用时 15 毫秒
11.
Schaap R. Schaafsma F. G. Huysmans M. A. Bosma A. R. Boot C. R. L. Anema J. R. 《Journal of occupational rehabilitation》2022,32(3):438-451
Journal of Occupational Rehabilitation - Purpose Health problems among employees with a lower socioeconomic position (SEP) often result from an interplay of problems on multiple life domains.... 相似文献
12.
13.
Osteosarcomatosis 总被引:10,自引:0,他引:10
Hopper KD; Moser RP Jr; Haseman DB; Sweet DE; Madewell JE; Kransdorf MJ 《Radiology》1990,175(1):233-239
A review of the 690 cases of osteosarcoma in the radiographic file of the Armed Forces Institute of Pathology revealed 29 cases of "osteosarcomatosis" (multiple skeletal sites of osteosarcoma). Fifteen of these patients were 18 years old and under and manifested rapidly appearing, usually symmetric, sclerotic metaphyseal lesions. The remaining 14 patients were more than 18 years old and had fewer, asymmetric sclerotic lesions. In most patients (28 of 29), a radiographically dominant skeletal tumor was seen. Pulmonary metastases occurred in the majority of patients and were detected at the same time as the bone lesions. These 29 patients were studied with regard to demographic data and skeletal distribution and radiographic appearance of their lesions. As a result of the findings, a metastatic origin from a primary dominant osteosarcoma is favored over a multifocal origin as the basis for osteosarcomatosis. Osteosarcomatosis is more commonly encountered in the mature skeleton than has been previously recognized. 相似文献
14.
Here we show that suppression of VH-DJH rearrangement in mice bearing a mu heavy (H) chain transgene (mu-tg mice) is associated with an extended period of DH-JH rearrangement, the first step of Immunoglobulin H chain gene rearrangement. Whereas DH-JH rearrangement is normally initiated and completed at the pro-B cell stage, in mu-tg mice it continues beyond this stage and occurs most frequently at the small (late) pre-B stage. Despite ongoing DH-JH rearrangement in late pre-B cells of mu-tg mice, VH-DJH rearrangement is not detectable in these cells. We infer that the lack of VH-DJH rearrangement primarily reflects tg-induced acceleration of B cell differentiation past the stage at which rearrangement of VH elements is permissible. In support of this inference, we find that the normal representation of early B lineage subsets is markedly altered in mu-tg mice. We suggest that the effect of a productive VH-DJH rearrangement at an endogenous H chain allele may be similar to that of a mu-tg; i.e., cells that make a productive VH-DJH rearrangement on the first attempt rapidly progress to a developmental stage that precludes VH-DJH rearrangement at the other allele (allelic exclusion). 相似文献
15.
Effects of diabetes mellitus on the biomechanical properties of human ankle cartilage 总被引:3,自引:0,他引:3
Athanasiou KA Fleischli JG Bosma J Laughlin TJ Zhu CF Agrawal CM Lavery LA 《Clinical orthopaedics and related research》1999,(368):182-189
Metabolic changes attributable to diabetes mellitus affect numerous organ systems in the body. For example, patients with diabetes have an increased number of musculoskeletal injuries and afflictions compared with patients without diabetes and experience more morbidity associated with injury and treatment. Although diabetes also may afflict articular cartilage, no studies have shown a conclusive link between diabetes and cartilage structural integrity. The objective of this study was to obtain and compare the intrinsic material properties of human ankle articular cartilage from patients with diabetes and those without diabetes. These biomechanical properties (aggregate modulus, Poisson's ratio, shear modulus, and permeability) were found to differ significantly between specimens from patients with diabetes and patients without diabetes. Specifically, cartilage from patients with diabetes was significantly softer and more permeable than cartilage from control subjects. For example, in the central portion of the talus, cartilage from patients with diabetes had a 38% smaller aggregate modulus, 37% smaller shear modulus, and 111% larger permeability than did tissue from patients without diabetes. These results provide evidence that joint pathologic processes in patients with diabetes may be associated with compromised structural integrity of articular cartilage. 相似文献
16.
Pathways to care for alcohol use disorders 总被引:1,自引:0,他引:1
17.
18.
Perry CL Komro KA Veblen-Mortenson S Bosma L Munson K Stigler M Lytle LA Forster JL Welles SL 《The Journal of school health》2000,70(3):84-88
The research community has criticized Drug Abuse Resistance Education (D.A.R.E.) because the extant literature indicates a lack of evidence that the elementary school program prevents drug use. Yet D.A.R.E. continues to be the most widely implemented drug use prevention program in the United States and has considerable community support. To date, the junior high D.A.R.E. program has not been evaluated. The Minnesota DARE PLUS Project is a randomized trial of 24 schools and communities. During 1999-2001, students in eight schools will receive the junior high D.A.R.E. curriculum in 7th grade; eight schools also will receive the curriculum as well as additional parent involvement, peer leadership, and community components in the 7th and 8th grades; and eight schools will serve as controls. This article describes the background and conceptualization, the curriculum and additional intervention components, and the evaluation methods of the DARE PLUS Project. 相似文献
19.
Abril N; Luque-Romero FL; Prieto-Alamo MJ; Rafferty JA; Margison GP; Pueyo C 《Carcinogenesis》1997,18(10):1883-1888
Here we confirm and extend our previous studies demonstrating that the
mutagenic potency of 1,2-dibromoethane (DBE) and dibromomethane (DBM) is
markedly enhanced (not prevented) in bacteria expressing the O6-
alkylguanine-DNA alkyltransferase (ATase) encoded by the Escherichia coli
ogt gene. We demonstrate that, in close parallel with mutagenesis, the Ogt
ATase sensitizes the bacteria to the lethal effects of these carcinogens,
suggesting that one or more of the potentially mutagenic lesions induced by
DBE and DBM in the presence of Ogt has additional lethal capacity. We
further demonstrate that the sensitization to both lethality and
mutagenesis by DBE and DBM is a property shared by other DNA
alkyltransferases. This objective was accomplished by quantifying the
induction of mutations and lethal events in ogt- ada- E. coli expressing an
exogenous bacterial or mammalian ATase from a multicopy plasmid. Mammalian
recombinant ATases enhanced the lethal and mutagenic actions of DBE and
suppressed the lack of sensitivity of the vector- transformed bacteria to
DBM. In most cases the order of effectiveness of the ATases ranked: murine
> human > Ogt > rat. Further comparisons included the full-length
Ada ATase from E. coli and a truncated Ada version (T-ada) that retains the
O6-methylguanine binding domain of the protein. The full-length Ada ATase
was effective in enhancing the lethality but not the mutagenicity induced
by DBE and DBM. The T-ada ATase provided less sensitization than Ada to
lethality by DBE, but of the three bacterial ATases T-ada yielded the
highest sensitization to mutagenesis by this compound. T-ada and Ada ATases
were in general less effective than the mammalian versions, with the
exception of the rat recombinant ATase. The effectiveness of the different
mammalian and bacterial ATases in promoting the deleterious actions of
dibromoalkanes was compared with the effectiveness of these proteins in
suppressing the lethal and mutagenic effects induced by
N-nitroso-N-methylurea. The ability to sensitize E. coli to the lethal and
mutagenic effects of DBE and DBM seems restricted to DNA alkyltransferase,
since overexpression of thioredoxin (Trx) or glutaredoxin (Grx1) in ogt-
ada- cells showed no effect, in spite of the reported potential of
bioactive dihaloethane- derived species to alkylate Trx.
相似文献
20.