全文获取类型
收费全文 | 72565篇 |
免费 | 5298篇 |
国内免费 | 2121篇 |
专业分类
耳鼻咽喉 | 176篇 |
儿科学 | 1779篇 |
妇产科学 | 841篇 |
基础医学 | 6918篇 |
口腔科学 | 467篇 |
临床医学 | 10924篇 |
内科学 | 11792篇 |
皮肤病学 | 363篇 |
神经病学 | 3391篇 |
特种医学 | 2840篇 |
外国民族医学 | 4篇 |
外科学 | 5154篇 |
综合类 | 13463篇 |
现状与发展 | 6篇 |
预防医学 | 4785篇 |
眼科学 | 702篇 |
药学 | 7089篇 |
83篇 | |
中国医学 | 7603篇 |
肿瘤学 | 1604篇 |
出版年
2024年 | 463篇 |
2023年 | 1081篇 |
2022年 | 1722篇 |
2021年 | 2782篇 |
2020年 | 2630篇 |
2019年 | 2168篇 |
2018年 | 2057篇 |
2017年 | 2258篇 |
2016年 | 2343篇 |
2015年 | 2350篇 |
2014年 | 4366篇 |
2013年 | 4691篇 |
2012年 | 3938篇 |
2011年 | 4187篇 |
2010年 | 3295篇 |
2009年 | 3004篇 |
2008年 | 3088篇 |
2007年 | 3256篇 |
2006年 | 2930篇 |
2005年 | 2693篇 |
2004年 | 2419篇 |
2003年 | 2230篇 |
2002年 | 1963篇 |
2001年 | 1883篇 |
2000年 | 1540篇 |
1999年 | 1337篇 |
1998年 | 1224篇 |
1997年 | 1317篇 |
1996年 | 1056篇 |
1995年 | 1037篇 |
1994年 | 994篇 |
1993年 | 752篇 |
1992年 | 749篇 |
1991年 | 659篇 |
1990年 | 519篇 |
1989年 | 500篇 |
1988年 | 494篇 |
1987年 | 397篇 |
1986年 | 375篇 |
1985年 | 551篇 |
1984年 | 457篇 |
1983年 | 287篇 |
1982年 | 415篇 |
1981年 | 306篇 |
1980年 | 273篇 |
1979年 | 199篇 |
1978年 | 164篇 |
1977年 | 152篇 |
1976年 | 140篇 |
1975年 | 68篇 |
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
71.
A. Queirós J. M. González-Méijome P. Fernandes J. Jorge J. B. Almeida M. A. Parafita 《Ophthalmic & physiological optics》2006,26(4):384-391
PURPOSE: The main objectives of this study were to determine the differences between non-synchronized intraocular pressure (IOP_N) and intraocular pressure readings synchronized with cardiac pulse and try to determine if these parameters are related to blood pressure values. METHODS: One hundred and sixty-five right eyes from 165 volunteers (107 females, 58 males) aged from 19 to 73 years (mean +/- S.D., 29.93 +/- 11.17) were examined with the Nidek NT-4000, a new non-contact tonometer that allows the measurement of IOP synchronized with the cardiac rhythm. IOP measurements in the four different modes of synchronization were taken in a randomized order. Three measures of each parameter were taken and then averaged. The blood pressure was determined three times with a portable manometer and mean values of systolic and diastolic pressure and the pulse rate were computed. Mean arterial pressure (MAP) was determined as being 1/3 of systolic plus 2/3 of diastolic blood pressure. RESULTS: The mean +/- S.D. values for the standard intraocular pressure (IOP_N: 14.76 +/- 2.86), intraocular pressure in the systolic instant or peak (IOP_P: 14.99 +/- 2.85), intraocular pressure in the middle instant between heartbeats or middle (IOP_M: 14.68 +/- 2.76), and intraocular pressure in the diastolic instant or bottom (IOP_B: 13.86 +/- 2.61) were obtained. The IOP_P was higher than the remaining values. A significant difference in mean IOP existed between IOP_B and the remaining modes of measuring (p < 0.05). Differences were statistically significant for all pair comparisons involving IOP_B. Arterial blood pressure values were systolic 125.5 +/- 14.22, diastolic 77.7 +/- 8.38 and MAP 93.64 +/- 9.44 mmHg. The pulse rate was 77.3 +/- 12.6 beats per minute. Except for the MAP (p = 0.025) there was no significant correlation between different IOP values and systolic or diastolic blood pressure, or pulse rate. CONCLUSIONS: NT-4000 is able to differentiate IOP values when synchronized with the cardiac rhythm and those differences are expected to be within a range of +/-2.5 to +/- 3.0 mmHg. IOP_B seems to be the parameter whose value differs from the non-synchronized and the remaining synchronized parameters in a significant way. Other than a weak association with MAP, no significant correlation between IOP and BP was found. The measurements of IOP readings for the three modes are consistent with timings during the cardiac cycle and IOP pulse cycle. 相似文献
72.
Naoyuki Hashiguchi Yu Chen Christian Rusu David B. Hoyt Wolfgang G Junger 《European Journal of Trauma》2005,31(4):379-388
AbstractBackground and Purpose: Polymorphonuclear neutrophils (PMNs) protect the host from invading microorganisms, but excessive PMN activation after trauma causes tissue injury. Rapid monitoring of PMN function is critical for the assessment of the inflammatory state of trauma patients. Here, the authors adapted two simple and rapid methods to measure oxidative burst and degranulation of human PMNs in whole blood to avoid potential interference of cell isolation procedures with the assessment of PMN function.Material and Methods: Heparinized blood was drawn from healthy volunteers or trauma patients, preincubated at 37 °C for 5 min, and stimulated with N-formyl-methionyl-leucyl-phenylalanine (fMLP). Four assays for oxidative burst were tested: (1) cytochrome C; (2) homovanillic acid (HVA); (3) Amplex® Red; and (4) flow cytometry with dihydrorhodamine 123 (DHR). PMN degranulation was assessed with flow cytometry using antibodies to: (1) CD11b/Mac-1 (CD18); (2) CD63; and (3) CD66b (CD67).Results: With the exception of the DHR method, all methods to measure oxidative burst were found to be unsuitable in whole blood due to interference of plasma proteins and hemoglobin with the fluorimetric or photometric readouts. By contrast, all degranulation methods were suitable for whole-blood studies. However, for the assessment of formyl peptide-induced degranulation, anti-antibodies to CD11b/Mac-1 and CD66b were up to five times more sensitive than antibodies to CD63. Thus, the degranulation and DHR methods were optimized for increased sensitivity, speed, and specificity and their usefulness to measure PMN function in trauma patients was tested.Conclusion: The whole-blood methods based on flow cytometry with DHR, anti-CD11b/Mac-1, and anti- CD66b are rapid, simple, and reliable techniques to assess PMN function for trauma research. 相似文献
73.
肌病肾病代谢综合征治疗进展 总被引:1,自引:0,他引:1
肌病肾病代谢综合征是急性动脉阻塞致骨骼肌溶解的严重并发症。积极治疗原发病,及早补液扩容、碱化尿液、早期血液净化治疗是降低截肢率、病死率的关键。本文就肌病肾病代谢综合征治疗进展作一综述。 相似文献
74.
75.
Carotid baroreflex function ceases
during vasovagal syncope 总被引:2,自引:0,他引:2
Shigehiko Ogoh PhD Stefanos Volianitis PhD Peter B. Raven PhD Niels H. Secher MD 《Clinical autonomic research》2004,14(1):30-33
Abstract. Despite the arterial baroreflex control of heart rate and
blood pressure, vasovagal syncope is a common cause of loss of
consciousness in people exposed to stimuli that reduce the
central blood volume, such as head-up tilt. Carotid baroreflex
function was evaluated using a rapid pulse train of neck
pressure and neck suction in three conscious volunteers who
developed a vasovagal episode during head-up tilt. The maximal
gain of the carotid-heart rate and carotid-blood pressure
baroreflex function curves were identified as measures of
carotid baroreceptor responsiveness. When presyncopal symptoms
developed, one further baroreflex assessment was obtained before
the subjects were returned to the supine position. The
bradycardia and hypotension exhibited during pre-syncope and
syncope reflected a leftward and downward relocation of both the
cardiac and vasomotor stimulusresponse curves. In addition,
during the vasovagal syncope, baroreflex control was suppressed
as blood pressure remained low during neck pressure stimuli. In
conclusion, arterial baroreflex function ceases during vasovagal
syncope. 相似文献
76.
Mieczysaw Pokorski Zdzisaw Matysiak Magdalena Marczak Robert P. Ostrowski Andrzej Kapuciski Iwona Matuszewska Marianna Kaska Zbigniew Czarnocki 《Drug development research》2003,60(3):217-224
N‐acyl‐dopamines are a novel class of biologically active lipids that have recently been identified in the brain and have the potential to interact with neural signaling pathways. This study seeks to determine the ability of N‐oleoyl‐dopamine, a synthetic amide of oleic acid and dopamine, to cross the blood brain barrier. We determined the tissue content of radioactivity in selected brain regions, in a short‐run study design, following injections of [3H]N‐oleoyl‐dopamine (0.4 µCi) into the internal carotid artery in the rat. These results were compared with intracarotid injections of [3H]dopamine and with intravenous injections of both radiolabeled compounds. The level of radioactivity was determined using liquid scintillation and was expressed as the percentage of its total dose injected per gram of tissue. We found that the 15‐min brain uptake of radioactivity, with no distinct regional variations, amounted to about 6% following the intracarotid [3H]N‐oleoyl‐dopamine, which was a significant 3–4‐fold increase over that following similar administration of [3H]dopamine. Intravenous injections of [3H]N‐oleoyl‐dopamine gave a much smaller yield of radioactivity in brain tissue samples which was still severalfold greater than that for intravenous [3H]dopamine. Qualitative thin‐layered chromatography screening showed the presence of unchanged N‐oleoyl‐dopamine in the brain following injections. We conclude that N‐oleoyl‐dopamine has an appreciable ability to cross the blood‐brain barrier, which contrasts the limited transfer of dopamine alone. N‐oleoyl‐dopamine might exert physiological effects due to its known affinity for the central vanilloid receptors or to better satisfying the brain tissue demand for dopamine. The study suggests a potential pharmacological role for N‐oleoyl‐dopamine delivered exogenously in helping regulate the brain function. Drug Dev. Res. 60:217–224, 2003. © 2003 Wiley‐Liss, Inc. 相似文献
77.
Trenkwalder P, Plaschke M, Aulehner R, Lydtin H. Felodipine or Hydrochlorothiazide/Triamterene for Treatment of' Hypertension in the Elderly: Effects on Blood Pressure, Hypertensive Heart Disease, Metabolic and Hormonal Parameters.
The aim of the study was to compare the antihypertensive efficacy of either felodipine or the diuretic combination hydrochlorothiazide/triamterene in a group (n = 65) of elderly (≥70 years) hypertensives (office blood pressure ≥ 60/95 mmHg) with special regard to ambulatory blood pressure monitoring, hypertensive heart disease and metabolic parameters. This was a randomized, double-blind study with a treatment period of 6 months. Reduction of office and 24-hr ambulatory blood pressure was comparable with both treatment regimens; after 6 months, 18 of 29 patients in the felodipine group (62%) and 20 of 27 patients in the diuretic group (74%; p = 0.4) were controlled. While episodes of ischemic type ST-segment depression were significantly reduced in the felodipine group (from 49 to 9 episodes), there was no significant change in the diuretic group (from 24 to 21 episodes). Both regimens decreased left ventricular wall thickness, but the decline in left ventricular muscle mass index was significant only for felodipine. Felodipine did not induce any change in metabolic or hormonal parameters; the diuretic combination significantly increased serum creatinine, uric acid, plasma renin activity, and plasma prorenin. Thus, the antihypertensive efficacy of felodipine and the diuretic combination was comparable in elderly hypertensives; only felodipine, however, improved parameters of hypertensive heart diesease and showed a neutral metabolic and hormonal profile. 相似文献
The aim of the study was to compare the antihypertensive efficacy of either felodipine or the diuretic combination hydrochlorothiazide/triamterene in a group (n = 65) of elderly (≥70 years) hypertensives (office blood pressure ≥ 60/95 mmHg) with special regard to ambulatory blood pressure monitoring, hypertensive heart disease and metabolic parameters. This was a randomized, double-blind study with a treatment period of 6 months. Reduction of office and 24-hr ambulatory blood pressure was comparable with both treatment regimens; after 6 months, 18 of 29 patients in the felodipine group (62%) and 20 of 27 patients in the diuretic group (74%; p = 0.4) were controlled. While episodes of ischemic type ST-segment depression were significantly reduced in the felodipine group (from 49 to 9 episodes), there was no significant change in the diuretic group (from 24 to 21 episodes). Both regimens decreased left ventricular wall thickness, but the decline in left ventricular muscle mass index was significant only for felodipine. Felodipine did not induce any change in metabolic or hormonal parameters; the diuretic combination significantly increased serum creatinine, uric acid, plasma renin activity, and plasma prorenin. Thus, the antihypertensive efficacy of felodipine and the diuretic combination was comparable in elderly hypertensives; only felodipine, however, improved parameters of hypertensive heart diesease and showed a neutral metabolic and hormonal profile. 相似文献
78.
光照疗法对新生儿红细胞谷胱甘肽还原酶活性的影响 总被引:3,自引:0,他引:3
作者对光照疗法(光疗)前及光疗后于口服维生素B_2(43例)和不予口服维生素B_2(17例)的黄疸新生儿的红细胞谷胱甘肽还原酶(GR)的活性进行了动态观察。结果显示,接受短期光疗的黄疸新生儿其红细胞GR活性较光疗前的GR活性有显著下降,光疗后予口服维生素B_2可使下降的红细胞GR活性回升,而不予补充维生素B_2者的红细胞GR活性继续下降。光疗的时间越长,红细胞GR活性的下降越明显,补充维生素B_2使红细胞GR活性回复到正常水平所需的时间也越长。短期光疗也可引起体内维生素B_2的降解,导致红细胞GR活性的下降,为避免因红细胞GR活性下降引起的红细胞额外破坏,对接受光疗的黄疸新生儿常规补充维生素B_2的是必要的。 相似文献
79.
Résumé Le saccharose, administré à une concentration d’au moins 12% chez le nouveau-né à terme (24% chez le prématuré), en petite
quantité (0,05 à 2 ml), dans une seringue ou mieux dans une tétine, 2 minutes avant la réalisation d’un soin douloureux avec
effraction cutanée (microprélèvement, ponction veineuse), permet de réduire, plus rarement d’abolir, les comportements de
détresse et/ou de douleur (pleurs et manifestations faciales). Il s’agit d’un moyen simple, non médicamenteux, et utilisable
partout, qui doit pouvoir représenter une aide non négligeable chez les nouveau-nés, pour la prise en charge de la douleur
provoquée par des soins modérément douloreux. Il peut être utilisé seul, mais son action limitée rend préférable de l’envisager
comme technique adjuvante. Son mode d’action reste encore peu clair, ainsi que sa tolérance en cas d’administrations pluri-quotidiennes.
Summary Sucrose of at least 12% concentration delivered to full-term infants (24% concentration for preterm infants), in a small volume of 0.05 to 2 ml, through a syringue or better through a pacifier, 2 minutes before blood sample such as heel-stick or venipuncture, can attenuate or hardly abolish stress and/ or pain (crying and facial expressions). It is a simple non pharmacological treatment, helpful in the management of pain related to moderate painful procedures. As it exerts moderate effects, it is better used as an adjuvant treatment than used alone. Mechanisms of effects are not clear yet, as well as the occurrence of adverse effects when repeated daily administrations.
相似文献
80.