全文获取类型
收费全文 | 844篇 |
免费 | 34篇 |
专业分类
耳鼻咽喉 | 9篇 |
儿科学 | 21篇 |
妇产科学 | 22篇 |
基础医学 | 108篇 |
口腔科学 | 54篇 |
临床医学 | 62篇 |
内科学 | 217篇 |
皮肤病学 | 4篇 |
神经病学 | 29篇 |
特种医学 | 10篇 |
外科学 | 74篇 |
综合类 | 13篇 |
预防医学 | 34篇 |
眼科学 | 74篇 |
药学 | 72篇 |
1篇 | |
中国医学 | 3篇 |
肿瘤学 | 71篇 |
出版年
2024年 | 3篇 |
2023年 | 3篇 |
2022年 | 8篇 |
2021年 | 20篇 |
2020年 | 19篇 |
2019年 | 23篇 |
2018年 | 16篇 |
2017年 | 14篇 |
2016年 | 16篇 |
2015年 | 20篇 |
2014年 | 23篇 |
2013年 | 32篇 |
2012年 | 61篇 |
2011年 | 65篇 |
2010年 | 27篇 |
2009年 | 24篇 |
2008年 | 45篇 |
2007年 | 41篇 |
2006年 | 49篇 |
2005年 | 46篇 |
2004年 | 34篇 |
2003年 | 33篇 |
2002年 | 31篇 |
2001年 | 13篇 |
2000年 | 26篇 |
1999年 | 19篇 |
1998年 | 8篇 |
1997年 | 4篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1992年 | 9篇 |
1991年 | 14篇 |
1990年 | 10篇 |
1989年 | 15篇 |
1988年 | 16篇 |
1987年 | 7篇 |
1986年 | 6篇 |
1985年 | 10篇 |
1984年 | 11篇 |
1983年 | 8篇 |
1982年 | 5篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 9篇 |
1977年 | 2篇 |
1974年 | 4篇 |
1972年 | 4篇 |
1965年 | 2篇 |
1962年 | 1篇 |
排序方式: 共有878条查询结果,搜索用时 15 毫秒
71.
PURPOSE: To evaluate corneal topographic features and tear secretion in eyes with the Hudson-Stahli line. METHODS: Keratometry, computerized videokeratography and Schirmer testing were performed in 50 cases with bilateral Hudson-Stahli line, and 55 controls without the Hudson-Stahli line. Similar tests were performed in 21 subjects with unilateral Hudson-Stahli line. RESULTS: Corneal topographic features and keratometry in the horizontal meridian were similar in cases and controls, and in fellow eyes of subjects with unilateral Hudson-Stahli line. Keratometry in the vertical meridian in cases (43.01 +/- 2.01) was significantly lesser than in controls (43.94 +/- 1.77) (P = 0.01). This value was not different in fellow eyes of patients with unilateral Hudson-Stahli line. Schirmer testing revealed significantly greater tear secretion in cases (16.72 +/- 4.99 mm) compared to controls (12.57 +/- 3.62 mm) (P < 0.01). In subjects with unilateral Hudson-Stahli line, mean Schirmer values in the eye with the line (17.52 +/- 6.86 mm) were significantly greater than in eyes without (13.67 +/- 4.64 mm) (P = 0.04). CONCLUSION: Formation of the Hudson-Stahli line may be dependent on the presence of normal tear secretion in the eye. 相似文献
72.
R. Mehrotra G. Jayaraman N. Padmanabhan 《Medical & biological engineering & computing》1985,23(1):55-62
To understand the special flow conditions which may be produced by the presence of stenosis in arteries, an analytical solution
is obtained for pulsatile laminar flow in an elliptic tube. Blood is approximated by a Newtonian model and the geometry of
the stenosis is introduced by specifying the change in area of cross-section of the stenosed artery with axial distance. The
results for velocity, pressure, shear stress and impedance are presented. These are compared with the steady flow results
as well as with those of the flow in a stenosed tube of circular cross-section. The study indicates that the fluid dynamic
characteristics of the flow are affected by the percentage of stenosis as well as the geometry of the stenosis. The frequency
of oscillation is also found to influence shearing stress and the impedance. 相似文献
73.
Anuj Shrestha Zeeshan Jawa Kathryn L. Koch Amy B. Rankin Qun Xiang Anand Padmanabhan Matthew S. Karafin Joshua J. Field 《Journal of clinical apheresis》2015,30(6):353-358
Red cell exchange (RCE) is a common procedure in adults with sickle cell disease (SCD). Implantable dual lumen Vortex (DLV) ports can be used for RCE in patients with poor peripheral venous access. We performed a retrospective cohort study of RCE procedures performed in adults with SCD. The main objective of the study was to compare the inlet speed, duration of procedures and rate of complications performed through DLV ports to those performed through temporary central venous and peripheral catheters. Twenty‐nine adults with SCD underwent a total of 318 RCE procedures. Twenty adults had DLV ports placed and 218 procedures were performed using DLV ports. Mean length of follow‐up after DLV port placement was 397 ± 263 days. Six DLV ports were removed due to infection and 1 for malfunction after a mean of 171 ± 120 days. Compared to temporary central venous and peripheral catheters, DLV port procedures had a greater rate of procedural complications, a longer duration, and a lower inlet speed (all P < 0.01). When accounting for the maximum allowable inlet speed to avoid citrate toxicity, 40% of DLV port procedures were greater than 10% below maximum speed, compared to 7 and 14% of procedures performed through temporary central venous and peripheral catheters (P < 0.0001). In conclusion, DLV ports can be used for RCE in adults with SCD, albeit with more procedural complications and longer duration. The smaller internal diameter and longer catheter of DLV ports compared to temporary central venous catheters likely accounts for the differences noted. J. Clin. Apheresis 30:353–358, 2015. © 2015 Wiley Periodicals, Inc. 相似文献
74.
Developmental programming: differential effects of prenatal exposure to bisphenol-A or methoxychlor on reproductive function 总被引:5,自引:0,他引:5
Increased occurrence of reproductive disorders has raised concerns regarding the impact of endocrine-disrupting chemicals on reproductive health, especially when such exposure occurs during fetal life. Prenatal testosterone (T) treatment leads to growth retardation, postnatal hypergonadotropism, compromised estradiol-positive feedback, polycystic ovaries, and infertility in the adult. Prenatal dihydrotestosterone treatment failed to affect ovarian morphology or estradiol-positive feedback, suggesting that effects of prenatal T may be facilitated via conversion of T to estradiol, thus raising concerns regarding fetal exposure to estrogenic endocrine-disrupting chemicals. This study tested whether fetal exposure to methoxychlor (MXC) or bisphenol A (BPA) would disrupt cyclicity in the ewe. Suffolk ewes were administered MXC (n=10), BPA (n=10) (5 mg/kg.d sc in cotton seed oil) or the vehicle (C; n=16) from d 30 to 90 of gestation. On d 60 of treatment, maternal MXC concentrations in fat tissue and BPA in blood averaged approximately 200 microg/g fat and 37.4+/-3.3 ng/ml, respectively. Birth weights of BPA offspring were lower (P<0.05) relative to C. There was no difference in the time of puberty between groups. BPA females were hypergonadotropic during early postnatal life and ended their breeding season later, compared with C. Characterization of cyclic changes after synchronization with prostaglandin F2alpha in five C, six MXC, and six BPA females found that the onset of the LH surge was delayed in MXC (P<0.05) and the LH surge magnitude severely dampened (P<0.05) in BPA sheep. These findings suggest that prenatal BPA and MXC exposure have long-term differential effects on a variety of reproductive endocrine parameters that could impact fertility. 相似文献
75.
Prenatal testosterone (T) treatment leads to polycystic ovarian morphology, enhanced follicular recruitment/depletion, and increased estradiol secretion. This study addresses whether expression of key ovarian genes and microRNA are altered by prenatal T excess and whether changes are mediated by androgenic or estrogenic actions of T. Pregnant Suffolk ewes were treated with T or T plus the androgen receptor antagonist, flutamide (T+F) from d 30 to 90 of gestation. Expression of steroidogenic enzymes, steroid/gonadotropin receptors, and key ovarian regulators were measured by RT-PCR using RNA obtained from fetal ovaries collected on d 65 [n = 4, 5, and 5 for T, T+F, and control groups, respectively] and d 90 (n = 5, 7, 4) of gestation. Additionally, fetal d 90 RNA were hybridized to multispecies microRNA microarrays. Prenatal T decreased (P < 0.05) Cyp11a1 expression (3.7-fold) in d 90 ovaries and increased Cyp19 (3.9-fold) and 5α-reductase (1.8-fold) expression in d 65 ovaries. Flutamide prevented the T-induced decrease in Cyp11a1 mRNA at d 90 but not the Cyp19 and 5α-reductase increase in d 65 ovaries. Cotreatment with T+F increased Cyp11a1 (3.0-fold) expression in d 65 ovaries, relative to control and T-treated ovaries. Prenatal T altered fetal ovarian microRNA expression, including miR-497 and miR-15b, members of the same family that have been implicated in insulin signaling. These studies demonstrate that maternal T treatment alters fetal ovarian steroidogenic gene and microRNA expression and implicate direct actions of estrogens in addition to androgens in the reprogramming of ovarian developmental trajectory leading up to adult reproductive pathologies. 相似文献
76.
M Chiriboga J Oropello K Padmanabhan J M Goldman 《The American journal of the medical sciences》1989,297(3):176-177
Goiters are an unusual cause of advanced upper airway obstruction. Previously described patients have been clearly symptomatic, and most have had substernal goiters. We present a patient with minimal symptoms with severe upper airway obstruction from a cervical goiter despite long-term therapy with thyroid hormone. Her spirometry exceeded criteria for urgent surgery. Patients with large goiters should have spirometry with flow-volume loop performed despite minimal or absent symptoms of respiratory distress. 相似文献
77.
V Padmanabhan C D Mieher M Borondy H I'Anson R I Wood T D Landefeld D L Foster I Z Beitins 《Endocrinology》1992,131(1):213-220
The pubertal process with its multifaceted neuroendocrine control provides an excellent model for the study of the regulation of FSH heterogeneity. We tested the hypothesis that during the pubertal transition in the female lamb 1) an increase in both pituitary and circulating bioactive FSH concentrations occur and 2) that the increase in bioactivity is associated with a change in the distribution pattern of both pituitary and circulating FSH isoforms. Pituitary and serum immunoreactive (I), and bioactive (B, Sertoli cell bioassay) FSH concentrations were measured in six prepubertal lambs (18 +/- 1 weeks, 29.9 +/- 2.8 kg body weight; mean +/- SE) and compared to those of six others (24.2 +/- 2.2 weeks of age, 41.4 +/- 2.5 kg body weight) during the pubertal transition period. Puberty was synchronized by pulsatile iv administration of GnRH (2 ng/kg every 2 h for 24 h and then at hourly intervals for the next 12 h) in a manner mimicking the I-LH pulse patterns observed during the natural transition to adulthood. Blood samples were collected at 12-min intervals for 4 h from both groups of lambs; for the pubertal group this included the final 32-36 h of GnRH administration. At the end of the study, a 25 ml volume of peripheral blood was collected from both prepubertal and pubertal females for the determination of serum FSH distribution patterns; the lambs were then euthanised, and pituitaries were removed for determination of pituitary hormone content and FSH isoform distribution patterns. In addition, the distribution pattern of I-FSH isoforms in the pituitary and serum from both groups of lambs were compared. The pubertal stages of all lambs were verified by measuring the size of follicles, the circulating concentrations of estradiol (E2) and inhibin, and the I-LH pulse patterns. Prepubertal lambs had low frequency I-LH pulses, small (2-3 mm) size ovarian follicles and low circulating concentrations of E2 (4.1 +/- 0.4 pg/ml) and inhibin (38.0 +/- 2.9 U/ml WHO). By contrast, all the pubertal lambs had hourly I-LH pulse frequency (induced with exogenous GnRH), a large (5-6 mm) follicle (in one lamb a 4-mm follicle), follicular phase levels of E2 (7.1 +/- 0.8 pg/ml), and higher concentrations of inhibin (53.2 +/- 3.1 U/ml).(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
78.
Exposure to testosterone (T) during d 30-90 of fetal life results in low-birth-weight offspring, hypergonadotropism, multifollicular ovaries, and early cessation of cyclicity. The multifollicular phenotype may result from failure of follicles to regress and consequent follicular persistence or, alternatively, increased follicular recruitment. We tested the hypothesis that prenatal exposure to excess T causes intrauterine growth retardation and increases ovarian follicular recruitment. Time-mated pregnant ewes were treated with 100 mg T propionate in cottonseed oil or vehicle twice weekly from d 30-90 of gestation. Ewes were euthanized near term, from d 139-141 of gestation (term is 147 d). After determining fetal measures and organ weights, ovaries were removed from fetuses of control and T-treated dams, and follicular distribution in each ovary was determined by morphometric quantification. Total number and percentage distribution of the various classes of follicles (primordial, primary, preantral, and antral follicles) were compared between treatment groups. Prenatally T-treated female fetuses were smaller in size, had an increased head circumference to fetal weight ratio (P < 0.01), increased adrenal to fetal weight ratio (P < 0.05), decreased number of follicles (P < 0.05), a decrease in percentage of primordial follicles (P < 0.001), and a corresponding increase in the remaining classes of follicles (P < 0.05). Ovarian findings support decreased ovarian reserve and enhanced follicular recruitment, potential contributors of early reproductive failure. The extent to which metabolic changes associated with intrauterine growth retardation contribute toward altered trajectory of ovarian folliculogenesis remains to be determined. 相似文献
79.
Thankappan KR Sivasankaran S Sarma PS Mini G Khader SA Padmanabhan P Vasan R 《Indian heart journal》2006,58(1):28-33
BACKGROUND, Hypertension is one of the major causes of cardiovascular morbidity and mortality. However, awareness, treatment, and control of hypertension remain major challenges worldwide. In this article, we present the baseline prevalence of hypertension from an ongoing intervention program for its control in a community-based sample in Kerala, Southern India. METHODS, We measured blood pressure, body weight, and height of 4955 individuals above the age of 30 yers (men;2159:mean-age: 50 years) and collected information on alcohol use, tobacco use, and other demographic variables using a pre-tested structured questionnaire. RESULTS, The overall prevalence of hypertension (JNC-VII) was 36.7% ( 95% CI:35.5-38.0; men: 36.0% and women 37.2% ) in multipile logistic regression analysis, a body mass index of >/=25 kg/m(2) was associated with a 1.65-fold (95% CI:1.37-1.98) prevalence of hypertension compared to a body mass index <25kg/m(2). Individuals with diabetes mellitus had 2.10 higher odds of hypertension prevalence (95% CI: 1.62-2.73) compared to people wihtout diabetes mellitus. Participants with increased waist circumference (90 cm in men, 85 cm in women) were 1.84 times more likely to be hypertensive compared to those with normal waist circumference (95% CI: 1.55-2.19). Among hypertensives, 24% were aware of the condition, 20% were on treatment, and 6.4% achieved effective blood pressure control. CONCLUSION, A higher body mass index, increased waist circumference, and self-reported diabetes mellitus were the important correlates of hypertension in our community-based sample. Our data emphasize the importance of educational interventions and appropriate lifestyle modifications that target increased body mass index and waist circumference to reduce the community burden of hypertension. 相似文献
80.
Jagadeeswaran P Gregory M Zhou Y Zon L Padmanabhan K Hanumanthaiah R 《Blood cells, molecules & diseases》2000,26(5):479-489
In this paper, we report the complete cDNA sequence of zebrafish prothrombin. The cDNA sequence predicts that zebrafish prothrombin is synthesized as a pre-proprotein consisting of a Gla domain, two kringle domains, and a two-chain protease domain. Zebrafish prothrombin is structurally very similar to human and other vertebrate prothrombins. Zebrafish and human prothrombin share 53% amino acid identity whereas zebrafish and hagfish prothrombin share 51% identity. Amino acid alignments of various prothrombins identified conservation of many of the functional/structural motifs suggesting that the vertebrate prothrombins may have similar functions. The three-dimensional structure of prothrombin predicted by homology modeling also revealed that the prothrombin fragment 1 and the catalytic domain structures are well conserved except for the insertion of an extra 7-amino-acid loop in the connecting region (CR) between the Gla and kringle I domain of fragment 1. Linkage analysis revealed that the prothrombin gene locus on linkage group 7 in zebrafish is syntenic to the human chromosome 11-prothrombin region suggesting its preservation through evolution. The availability of this cDNA sequence in zebrafish adds to our knowledge of the zebrafish hemostatic system and provides support for the view that similarities between zebrafish and mammalian coagulation exist, thus underscoring the relevance of the zebrafish model for studying human hemostasis. 相似文献