全文获取类型
收费全文 | 24412篇 |
免费 | 1544篇 |
国内免费 | 135篇 |
专业分类
耳鼻咽喉 | 249篇 |
儿科学 | 627篇 |
妇产科学 | 505篇 |
基础医学 | 3678篇 |
口腔科学 | 1042篇 |
临床医学 | 2234篇 |
内科学 | 5679篇 |
皮肤病学 | 670篇 |
神经病学 | 2135篇 |
特种医学 | 563篇 |
外科学 | 2226篇 |
综合类 | 51篇 |
一般理论 | 10篇 |
预防医学 | 2351篇 |
眼科学 | 477篇 |
药学 | 1650篇 |
中国医学 | 112篇 |
肿瘤学 | 1832篇 |
出版年
2024年 | 33篇 |
2023年 | 256篇 |
2022年 | 604篇 |
2021年 | 1024篇 |
2020年 | 613篇 |
2019年 | 823篇 |
2018年 | 930篇 |
2017年 | 647篇 |
2016年 | 772篇 |
2015年 | 842篇 |
2014年 | 1110篇 |
2013年 | 1407篇 |
2012年 | 2204篇 |
2011年 | 2292篇 |
2010年 | 1200篇 |
2009年 | 991篇 |
2008年 | 1692篇 |
2007年 | 1629篇 |
2006年 | 1482篇 |
2005年 | 1372篇 |
2004年 | 1193篇 |
2003年 | 1007篇 |
2002年 | 882篇 |
2001年 | 101篇 |
2000年 | 67篇 |
1999年 | 91篇 |
1998年 | 128篇 |
1997年 | 107篇 |
1996年 | 87篇 |
1995年 | 69篇 |
1994年 | 57篇 |
1993年 | 58篇 |
1992年 | 40篇 |
1991年 | 35篇 |
1990年 | 27篇 |
1989年 | 30篇 |
1988年 | 22篇 |
1987年 | 13篇 |
1986年 | 25篇 |
1985年 | 19篇 |
1984年 | 26篇 |
1983年 | 14篇 |
1982年 | 19篇 |
1981年 | 11篇 |
1980年 | 6篇 |
1979年 | 6篇 |
1978年 | 6篇 |
1977年 | 5篇 |
1966年 | 2篇 |
1961年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 19 毫秒
21.
22.
Andrew E. Springer Kayan Lewis Steven H. Kelder Maria E. Fernandez Cristina S. Barroso Deanna M. Hoelscher 《Journal of immigrant and minority health / Center for Minority Public Health》2010,12(5):769-780
Research on physical activity (PA) by level of acculturation in Hispanic children is limited and findings have been mixed.
We examined PA participation by primary language used with parents in a representative sample of 4th, 8th, and 11th grade
Texas public school students. Mixed-effects regression models were conducted using cross-sectional data from the 2004–2005
School Physical Activity and Nutrition Study (n = 22,049). Self-reported PA was compared among three language-ethnic groups: Spanish-Hispanic (SH) (referent); English-Hispanic
(EH); and English-Other (EO). EH and/or EO girls were generally between 1.25 and 2.58 [OR] times more likely to participate in PA across grade levels,
with the largest differences found for school sports in 8th grade girls. EH and EO 8th grade boys were 1.71 (CI: 1.40, 2.10)
and 2.06 (CI: 1.68, 2.51) times, respectively, more likely to participate in school sports. Findings indicate important disparities
in Spanish-speaking Hispanic children’s PA participation. 相似文献
23.
24.
25.
26.
27.
Plasma levels and vascular effects of vasopressin in patients undergoing coronary artery bypass grafting. 总被引:1,自引:0,他引:1
Susana Novella Ana Cristina Martínez Rosa María Pagán Medardo Hernández Albino García-Sacristán Angel González-Pinto José María González-Santos Sara Benedito 《European journal of cardio-thoracic surgery》2007,32(1):69-76
OBJECTIVE: Recent studies have suggested that endogenous vasopressin (AVP) acts as a spasmogen during coronary artery bypass grafting (CABG). Given that AVP could induce vasospasm in the grafted vessel, we assessed the release of this peptide during and after CABG, and explored ways of counteracting its contractile effect on the internal mammary artery (IMA). METHODS: Plasma levels of AVP were determined by radioimmunoassay in 16 patients before, during and after CABG. Using isometric force recording techniques, we also investigated the mechanisms involved in the contractile effect of AVP in ring preparations of IMA specimens taken from 95 patients. RESULTS: Plasma AVP levels peaked after the start of cardiopulmonary bypass (CPB) and correlated well with serum osmolality (Pearson's r=0.9490; P<0.0001; n=16). An inverse correlation was observed between plasma AVP levels recorded at this stage and the maximal contraction induced in vitro by AVP in vascular rings from the same patients (Pearson's r=-0.6968; P<0.01; n=16). No change in the AVP response was produced by endothelium removal, exposure to the NO precursor (3 x 10(-4)M L-arginine), inhibition of nitric oxide (NO) synthase (3 x 10(-5) M L-NAME) or soluble guanylate cyclase (3 x 10(-6) M 1H-[1,2,4]oxadiazol [4,3,-alpha]quinoxalin-1-one (ODQ)), removal of the superoxide anion (100 U/ml superoxide dismutase (SOD) plus 1200 U/ml catalase) or hydroxyl radical (10(-4) M deferoxamine), or specific alpha1 - (10(-6) M prazosin) or endothelin (10(-5) M bosentan) receptor antagonism. In contrast, adenylate cyclase activation (3 x 10(-8) M forskolin) reduced the contractile response to AVP, while prostanoid synthesis (3 x 10(-6) M indomethacin) inhibition and blockade of Ca2+ -activated potassium channels (KCa) (10(-3) M tetraethylammonium (TEA)) enhanced AVP contraction. Age, gender and smoking also modified the AVP response. CONCLUSION: Our findings suggest a role for AVP as a modulator of vascular tone in human IMA. The effect of AVP is dependent on prostanoids and Ca2+ -activated K+ channels, so its dysfunction in pathophysiological cardiovascular processes could mean that AVP, among other factors, produces vasospasm in IMA grafts. 相似文献
28.
Juan J. Muoz Cristina Roca Jos L. Santos Miguel Arroyo Rafael E. de Salamanca 《Basic & clinical pharmacology & toxicology》1993,73(4):189-191
Two alternatives for the treatment of lead intoxication, administration of zinc or a thiol donor, S-adenosyl-L-methionine (SAM), were analysed. Rats were exposed to lead (Pb)-acetate (60 mg/1) in drinking water during 90 days; one group also received SO4Zn in water (40 mg/l), while another received both Pb and SAM (5 mg/24 hr intraperitoneally. Erythrocytic δ-aminolaevulinic dehydratase (ALA-D) activity was significantly reduced (P<0.001) both in rats receiving Pb alone and in rats receiving Pb and each of the other two treatments. The high erythrocytic uroporphyrinogen synthetase (URO-S) activity noticed in Pb administered rats, was significantly (P< 0.001) reduced in animals treated either with zinc or with SAM. Hepatic ALA-D activity tended to decrease while renal enzyme activity was not modified by the low level Pb exposure used in this work. Interestingly, SAM treated rats in both tissues exhibited significantly (P<0.01) higher activities of the enzyme. It is argued that SAM treatment causes a surplus of thiols that allows the full expression of ALA-D catalytic activity. 相似文献
29.
Arnold Criel Gregor Verhoef Robert Vlietinck Cristina Mecucci Johan Billiet Lucienne Michaux Peter Meeus ries Louwagie Angeline Van Orshoven Achiel Van Hoof Mark Boogaerts Herman Van den Berghe & Chris De Wolf-Peeters 《British journal of haematology》1997,97(2):383-391
We analysed a group of 390 patients, diagnosed with chronic lymphocytic leukaemia (CLL). Cases were subclassified as morphologically typical and atypical CLL according to the criteria of the FAB proposal. Typical CLL cases were mostly diagnosed at a low-risk stage (Binet A/Rai 0), required no immediate treatment and expected a long survival; atypical CLL cases mostly presented at a more advanced risk stage (Binet B/Rai I–II), usually required immediate treatment and their survival was shorter. Moreover, clinical staging was of prognostic significance in typical but not in atypical cases. In typical CLL, del(11q) was the most common chromosomal abnormality (21%) whereas in atypical CLL trisomy 12 was found in about 65% of the cases documented with an abnormal karyotype. Although chromosomal abnormalities were associated with a poor survival in typical CLL, they are of no prognostic significance in atypical CLL. Based on these data, we conclude that subtyping CLL by morphology enables the identification of two groups of cases, each characterized by a specific clinical presentation, different cytogenetic abnormalities and prognostic parameters. We speculate that these two groups may represent two related, but different, diseases with different prognostic parameters and a different survival. 相似文献
30.
Franco Rilke M. D. F. R. C. Umberto Veronesi M. D. Alberto Luini M. D. Cristina Brambilla M. D. Viviana Galimberti M. D. Stefano Zurrida M. D. Silvana Pilotti M. D. M. I. A. C. Silvana Di Palma M. D. Roberto Zucali M. D. Laura Lozza M. D. 《The breast journal》1996,2(3):176-180
Abstract: Breast conservation surgery is an effective and safe treatment for many breast carcinomas. It may be possible to further limit the extent of resection (or expand the indication for breast conservation) by the application of preoperative chemotherapy and radiotherapy. We explored the feasibility of this in a pilot study.
Seventy-three patients (mean age 48, 63% premenopausal) with confirmed breast cancer, less than 2.5 cm, received chemotherapy (Group A) or chemotherapy plus radiotherapy (Group B) prior to limited resection (tumorectomy). Axillary dissection was always performed. Results: In 6/31 (19%) Group A and 17/42 (40%) Group B patients the tumor was not palpable after preoperative treatment, with complete pathological remission in 1 and 3 cases respectively. Histologic grading, mitosis, cellular alteration, and cellularity evaluations indicated a consistently greater therapeutic effect with chemoradiotherapy than with chemotherapy alone.
In conclusion, radiotherapy appears useful in the preoperative treatment of breast cancer and its use in association with various drug combinations should be further explored. 相似文献
Seventy-three patients (mean age 48, 63% premenopausal) with confirmed breast cancer, less than 2.5 cm, received chemotherapy (Group A) or chemotherapy plus radiotherapy (Group B) prior to limited resection (tumorectomy). Axillary dissection was always performed. Results: In 6/31 (19%) Group A and 17/42 (40%) Group B patients the tumor was not palpable after preoperative treatment, with complete pathological remission in 1 and 3 cases respectively. Histologic grading, mitosis, cellular alteration, and cellularity evaluations indicated a consistently greater therapeutic effect with chemoradiotherapy than with chemotherapy alone.
In conclusion, radiotherapy appears useful in the preoperative treatment of breast cancer and its use in association with various drug combinations should be further explored. 相似文献