全文获取类型
收费全文 | 6246篇 |
免费 | 534篇 |
国内免费 | 24篇 |
专业分类
耳鼻咽喉 | 76篇 |
儿科学 | 226篇 |
妇产科学 | 145篇 |
基础医学 | 694篇 |
口腔科学 | 162篇 |
临床医学 | 735篇 |
内科学 | 1156篇 |
皮肤病学 | 93篇 |
神经病学 | 573篇 |
特种医学 | 292篇 |
外科学 | 913篇 |
综合类 | 152篇 |
一般理论 | 2篇 |
预防医学 | 740篇 |
眼科学 | 150篇 |
药学 | 350篇 |
中国医学 | 8篇 |
肿瘤学 | 337篇 |
出版年
2023年 | 65篇 |
2022年 | 99篇 |
2021年 | 234篇 |
2020年 | 105篇 |
2019年 | 174篇 |
2018年 | 196篇 |
2017年 | 145篇 |
2016年 | 138篇 |
2015年 | 178篇 |
2014年 | 207篇 |
2013年 | 275篇 |
2012年 | 330篇 |
2011年 | 328篇 |
2010年 | 190篇 |
2009年 | 188篇 |
2008年 | 279篇 |
2007年 | 273篇 |
2006年 | 218篇 |
2005年 | 234篇 |
2004年 | 219篇 |
2003年 | 195篇 |
2002年 | 158篇 |
2001年 | 137篇 |
2000年 | 167篇 |
1999年 | 125篇 |
1998年 | 94篇 |
1997年 | 68篇 |
1996年 | 80篇 |
1995年 | 55篇 |
1994年 | 81篇 |
1993年 | 63篇 |
1992年 | 88篇 |
1991年 | 96篇 |
1990年 | 85篇 |
1989年 | 93篇 |
1988年 | 92篇 |
1987年 | 74篇 |
1986年 | 76篇 |
1985年 | 59篇 |
1984年 | 57篇 |
1983年 | 65篇 |
1982年 | 56篇 |
1981年 | 43篇 |
1980年 | 48篇 |
1979年 | 58篇 |
1978年 | 57篇 |
1977年 | 39篇 |
1976年 | 32篇 |
1973年 | 32篇 |
1970年 | 30篇 |
排序方式: 共有6804条查询结果,搜索用时 31 毫秒
51.
Heritability of C-Reactive Protein and Association with Apolipoprotein E Genotypes in Japanese Americans 总被引:1,自引:0,他引:1
M. A. Austin C. Zhang S. E. Humphries W. L. Chandler P. J. Talmud K. L. Edwards D. L. Leonetti M. J. Mcneely W. Y. Fujimoto 《Annals of human genetics》2004,68(3):179-188
Numerous studies have demonstrated that increased C‐reactive protein (CRP) levels predict coronary heart disease, stroke, peripheral vascular disease, and diabetes, and are associated with features of the metabolic syndrome. Only three previous studies have investigated the heritability of CRP levels, primarily in samples of Caucasian families.The purpose of the present study was to estimate the magnitude of genetic influences on CRP levels, and to examine potential associations between variation in the APOE gene and CRP levels, using a sample of 562 individual Japanese Americans from 68 extended kindreds. In general, correlation coefficients between first‐degree relatives for CRP were approximately 0.2, and spouse correlations did not differ from zero, consistent with genetic influences. Heritability estimates were approximately 0.3 (p < 0.01), even with adjustment for factors known to influence CRP levels. A significant relationship was seen between unadjusted CRP levels and APOE genotypes (p = 0.02), with the highest mean CRP level among ?2 carriers (1.20 mg/L), and nearly the same mean levels among ?3/?3 subjects and ?4 carriers (0.72 and 0.74 mg/L, respectively). However, this relationship was diminished with adjustment for covariates (p = 0.07). These results demonstrate the presence of both genetic and environmental effects on CRP levels among Asian Americans, and additional studies are needed to determine if the APOE gene contributes to these genetic influences. 相似文献
52.
Effects of treatment on fertility in long-term survivors of childhood or adolescent cancer 总被引:8,自引:0,他引:8
J Byrne J J Mulvihill M H Myers R R Connelly M D Naughton M R Krauss S C Steinhorn D D Hassinger D F Austin K Bragg 《The New England journal of medicine》1987,317(21):1315-1321
In a retrospective cohort study of survivors of cancer and of controls, we estimated the risk of infertility after treatment for cancer during childhood or adolescence. We interviewed 2283 long-term survivors of childhood or adolescent cancer diagnosed in the period from 1945 through 1975, who were identified at five cancer centers in the United States. Requirements for admission to the study were diagnosis before the age of 20, survival for at least five years, and attainment of the age of 21. In addition, 3270 controls selected from among the survivors' siblings were interviewed. Cox regression analysis showed that cancer survivors who married and were presumed to be at risk of pregnancy were less likely than their sibling controls to have ever begun a pregnancy (relative fertility, 0.85; 95 percent confidence interval, 0.78 to 0.92). Radiation therapy directed below the diaphragm depressed fertility in both sexes by about 25 percent. Chemotherapy with alkylating agents, with or without radiation to sites below the diaphragm, was associated with a fertility deficit of about 60 percent in the men. Among the women, there was no apparent effect of alkylating-agent therapy administered alone (relative fertility, 1.02) and only a moderate fertility deficit when alkylating-agent therapy was combined with radiation below the diaphragm (relative fertility, 0.81). Relative fertility in the survivors varied considerably according to sex, site of cancer, and type of treatment; these factors should be taken into consideration in counseling survivors about the long-term consequences of disease. 相似文献
53.
Yang GC; Croaker D; Zhang AL; Manglick P; Cartmill T; Cass D 《Human molecular genetics》1998,7(6):1047-1052
Lethal white foal syndrome (LWFS) is a congenital anomaly of horses
characterized by a white coat colour and aganglionosis of the bowel, which
is similar to Hirschsprung disease (HSCR). We decided to investigate
possible mutations of the endothelin-B receptor gene ( EDNRB ) in LWFS as
recent studies in mutant rodents and some patients have demonstrated EDNRB
defects. First, we identified a full-length cDNA for horse EDNRB . This
cDNA fragment contained a 1329 bp open reading frame which encoded 443
amino acid residues. The predicted amino acid sequence was 89, 91 and 85%
identical to human, bovine and mouse as well as rat EDNRB respectively, but
only 55% identical to the human, bovine and rat endothelin A receptor
(EDNRA). Secondly, sequence analysis, together with allele-specific PCR and
the amplification- created restriction site (ACRS) technique, revealed a
dinucleotide TC-- >AG mutation, which changed isoleucine to lysine in
the predicted first transmembrane domain of the EDNRB protein. This was
associated with LWFS when homozygous and with the overo phenotype when
heterozygous.
相似文献
54.
Nadler R Luo Y Zhao W Ritchey JK Austin JC Cohen MB O'Donnell MA Ratliff TL 《Clinical and experimental immunology》2003,131(2):206-216
55.
Robert H. Carlson Chris Gabel Shirley Chan Robert H. Austin 《Biomedical microdevices》1998,1(1):39-47
We demonstrate a novel activation behavior of human leucocyte adhesion under physiological flow conditions in a microfabricated silicon array of channels with length scales similar to those of human capillaries. Vital nuclei stains and cell specific, flourochrome labeled antibodies reveal that the equilibrium distribution of stuck cells in the arrays displays a strong dependence on cell type and nuclear morphology, and there is eventual separation of the two cell types in the array. The distortion of the cells is the same as they experience in vivo and the response of the granulocytes is consistent with a model describing adhesion as a function of the distortion of the cell by its environment; in other words, activated adhesion. We propose that this complex non-random behavior is due to a deformation activated change in the cells relevant to observed in vivo behavior. 相似文献
56.
Goldfarb JM Austin C Peskin B Lisbona H Desai N de Mola JR 《Human reproduction (Oxford, England)》2000,15(5):1075-1078
The purpose of our study was to review and evaluate retrospectively the experience of an in-vitro fertilization (IVF) surrogate gestational programme in a tertiary care and academic centre. In a 15 year period from 1984 to 1999, a total of 180 cycles of IVF surrogate gestational pregnancy was started in 112 couples. On average, the women were 34.4 +/- 4.4 years of age, had 11.1 +/- 0.72 oocytes obtained per retrieval, 7.1 +/- 0.5 oocytes fertilized and 5. 8 +/- 0.4 embryos subsequently cleaved. Sixteen cycles (8.9%) were cancelled due to poor stimulation. Except for six cycles (3.3%) where there were no embryos available, an average of 3.2 +/- 0.1 embryos was transferred to each individual recipient. The overall pregnancy rate per cycle after IVF surrogacy was 24% (38 of 158), with a clinical pregnancy rate of 19% (30 of 158), and a live birth rate of 15.8% (25 of 158). When compared to patients who underwent a hysterectomy, individuals with congenital absence of the uterus had significantly more oocytes retrieved (P < 0.006), fertilized, cleaved and more embryos available for transfer despite being of comparable age. IVF surrogate gestation is an established, yet still controversial, approach to the care of infertile couples. Take-home baby rates are comparable to conventional IVF over the same 15 year span in our programme. Patients with congenital absence of the uterus responded to ovulation induction better than patients who underwent a hysterectomy, perhaps due in part to ovarian compromise from previous surgical procedures. 相似文献
57.
R T Parmley S S Spicer A Komiyama L W Dow R L Austin 《Experimental and molecular pathology》1979,30(1):41-54
Cytochemical methods were used to determine the ultrastructural distribution of antimonate precipitable cations, anionic complex carbohydrate, acid phosphatase, and peroxidase in blood basophils from patients with chronic myelocytic leukemia and markedly elevated basophil counts. The morphology of these basophils varied but was generally similar to that reported for normal basophils. Antimonate precipitable cations were sparse in specific granules but more abundant in extra-granular cytoplasm and in vesicular structures of many basophils and, although varying with the fixation method, were distributed atypically in nuclei in a pattern similar to that seen in mast cells. The dialyzed iron technique diffusely stained anionic complex carbohydrate in the specific granules of basophils, and high iron diamine staining disclosed a sulfated mucosubstance in these granules. Acid phosphatase and peroxidase were distributed in a pattern similar to that of the acid mucosubstance in the basophil granules, and their presence suggested a lysosomal function for these granules 相似文献
58.
M B Cohen J H Austin A Smith-Vaniz J Lutzky M M Grimes 《American journal of clinical pathology》1989,92(1):101-104
Pulmonary interstitial fibrosis, a well-known toxic effect of bleomycin therapy, usually presents radiographically as diffuse reticularity. The authors report an unusual case of biopsy-proven bleomycin toxicity that presented as pulmonary nodules mimicking metastatic tumor. The histologic findings resembled those seen in the diffuse form of toxicity but notably also included foci of bronchiolitis obliterans. 相似文献
59.
Elevated mononuclear leukocyte phosphodiesterase in allergic dogs with and without airway hyperresponsiveness 总被引:1,自引:0,他引:1
C A Hirshman D B Leu D R Austin S C Chan L Veith J M Hanifin 《The Journal of allergy and clinical immunology》1987,79(1):46-53
To investigate if mononuclear leukocyte beta-adrenergic hyporesponsiveness of Basenji greyhound (BG) dogs is associated with atopy or nonspecific airway hyperresponsiveness, we examined the relationship between mononuclear leukocyte cAMP phosphodiesterase levels, airway responsiveness to methacholine, and intradermal allergen responses in 17 BG dogs, five unrelated purebred Basenjis, and five greyhounds. BG dogs were hyperresponsive to aerosols of methacholine compared to Basenjis and greyhounds. Both BG dogs and Basenjis were allergic and had increased leukocyte cAMP phosphodiesterase activity compared to greyhounds. We concluded that the leukocyte abnormality is not associated with airway hyperresponsiveness. The leukocyte abnormality is either associated with the allergic state, with some hereditary trait that BG dogs acquired from the Basenji ancestry, or the leukocyte abnormality is necessary but not sufficient for the development of airway hyperresponsiveness. 相似文献
60.