全文获取类型
收费全文 | 36487篇 |
免费 | 1809篇 |
国内免费 | 496篇 |
专业分类
耳鼻咽喉 | 89篇 |
儿科学 | 1052篇 |
妇产科学 | 274篇 |
基础医学 | 4755篇 |
口腔科学 | 450篇 |
临床医学 | 4819篇 |
内科学 | 8584篇 |
皮肤病学 | 289篇 |
神经病学 | 1627篇 |
特种医学 | 1467篇 |
外国民族医学 | 3篇 |
外科学 | 3816篇 |
综合类 | 3721篇 |
现状与发展 | 2篇 |
预防医学 | 1498篇 |
眼科学 | 132篇 |
药学 | 3390篇 |
9篇 | |
中国医学 | 896篇 |
肿瘤学 | 1919篇 |
出版年
2023年 | 430篇 |
2022年 | 905篇 |
2021年 | 1147篇 |
2020年 | 996篇 |
2019年 | 1225篇 |
2018年 | 1274篇 |
2017年 | 1003篇 |
2016年 | 954篇 |
2015年 | 1167篇 |
2014年 | 2385篇 |
2013年 | 2403篇 |
2012年 | 1782篇 |
2011年 | 2192篇 |
2010年 | 1658篇 |
2009年 | 1765篇 |
2008年 | 1783篇 |
2007年 | 1731篇 |
2006年 | 1583篇 |
2005年 | 1317篇 |
2004年 | 1190篇 |
2003年 | 959篇 |
2002年 | 764篇 |
2001年 | 688篇 |
2000年 | 652篇 |
1999年 | 562篇 |
1998年 | 440篇 |
1997年 | 475篇 |
1996年 | 409篇 |
1995年 | 395篇 |
1994年 | 369篇 |
1993年 | 316篇 |
1992年 | 264篇 |
1991年 | 235篇 |
1990年 | 241篇 |
1989年 | 173篇 |
1988年 | 191篇 |
1987年 | 172篇 |
1986年 | 135篇 |
1985年 | 259篇 |
1984年 | 348篇 |
1983年 | 184篇 |
1982年 | 235篇 |
1981年 | 215篇 |
1980年 | 194篇 |
1979年 | 166篇 |
1978年 | 123篇 |
1977年 | 124篇 |
1976年 | 139篇 |
1975年 | 129篇 |
1974年 | 115篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
13.
Unique variant of partial anomalous pulmonary venous connection with intact atrial septum 总被引:1,自引:0,他引:1
Summary Partial anomalous pulmonary venous connections (PAPVCs) are rare in association with an intact atrial septum. However, the diagnosis should be considered in patients with otherwise unexplained findings of left-to-right shunt and right heart enlargement. An unusual variant is presented, which we considered unsuitable for operative repair, based on findings at catheterization. Developmental, hemodynamic, and surgical considerations are discussed. 相似文献
14.
J. Pillgram-Larsen J. Thorvaldson E. Thaulow G. Semb A. Serck-Hanssen 《European journal of cardio-thoracic surgery》1987,1(3):183-185
A rare case of a rhabdomyoma originating from the surface of the right atrium in a 20-year-old female is reported. The tumor showed electrical activity and caused both outflow obstruction and tamponade symptoms. It was successfully removed by a right-sided thoracotomy. The clinical course, diagnostic investigations, and the therapeutical approach of this rare lesion are discussed. 相似文献
15.
Taurine has been proposed as an inhibitory neurotransmitter or neuromodulator in the vertebrate central nervous system. Within the spinal cord, taurine has been shown to have a direct inhibitory effect on spinal neurons and to have a selective antinociceptive effect on chemically induced nociception. Although sufficient data exists to suggest that taurine plays a neurotransmitter or neuromodulatory role in the spinal cord, it is not known whether this amino acid is present in axon terminals nor if this amino acid has a unique pattern of distribution within spinal tissue. To address these questions a monoclonal antibody against taurine was employed to localize taurine-like immunoreactivity in the dorsal horn of the rat spinal cord by using both light and electron microscopic techniques. Taurine-like immunoreactivity was most dense and most prominent in laminae I and II of the dorsal horn. A moderate amount of immunoreactivity was also present in laminae VIII and IX and X while the remaining laminae were only lightly stained. In laminae I and II taurine-like immunostaining was evident within neuronal cell bodies, dendrites, myelinated and unmyelinated axons, axon terminals, and astrocytes and their processes. Cell counts of these two laminae indicated that approximately 30% of neuronal perikarya at the C2 level, 52% of neuronal perikarya at the T6 level, and 18% of neuronal perikarya at the L2 level of the cord exhibited taurine-like immunoreactivity. With preembedding diaminobenzidine staining, approximately 20% of the axons examined in laminae I and II were found to be immunoreactive for taurine. Using postembedding immunogold staining in combination with quantitative procedures, the highest densities of gold particles were found in axon terminals containing pleomorphic vesicles and forming symmetrical synapses (36.8 particles/micron2), in a subpopulation of myelinated axons (34.2 particles/micron2), in a subpopulation of neuronal dendrites (32.6 particles/micron2), and in capillary endothelial cells (39.8 particles/micron2). Moderate labeling occurred in astrocytes (20.9 particles/micron2) and neuronal perikarya (18.7 particles/micron2). The localization of taurine to presumptive inhibitory axon terminals provides anatomical support for the hypothesis that taurine may serve an inhibitory neurotransmitter role in the superficial dorsal horn of the spinal cord. On the other hand, its localization to astrocytes and endothelial cells within both the dorsal ventral horns implies that it serves other nonneuronal functions as well. 相似文献
16.
Phase I Study of Paclitaxel by Three-hour Infusion: Hypotension Just after Infusion Is One of the Major Dose-limiting Toxicities 总被引:4,自引:0,他引:4
Tomohide Tamura Yasutsuna Sasaki Yutaka Nishiwaki Nagahiro Saijo 《Cancer science》1995,86(12):1203-1209
The primary objectives of this study were to determine the maximum tolerated dose (MTD) of paclitaxel administered by 3-h infusion to patients with solid tumors, and to characterize the pharmacokinetics of a 3-h infusion in comparison with those of a 24-h infusion. Twenty-seven patients each received one of six levels of paclitaxel, 105, 135, 180, 210, 240 and 270 mg/m2 , with premedication. Two patients given 240 mg/m2 and one patient given 270 mg/m2 unexpectedly had grade 3/4 hypotension just after finishing the paclitaxel infusion. Peripheral neuropathy was also dose-limiting at 270 mg/m2 . Although granulocytopenia was significantly less severe than with a 24-h infusion, more than half of the patients experienced grade 4 toxicity at doses of 240 or 270 mg/m2 . Severe hypersensitivity reactions (HSRs) were not observed. Pharmacokinetic studies using high performance liquid chromatography demonstrated proportionally greater increases in the peak plasma concentration and area under the curve, and decreases in clearance and volume of distribution with increasing dose, suggesting non-linear pharmacokinetics of paclitaxel when given by 3-h infusion. The MTD of paclitaxel given as a 3-h infusion was determined to be 240 mg/m2 with dose-limiting toxicities of granulocytopenia, peripheral neuropathy and hypotension. Hypotension just after infusion, induced by 3-h infusion of paclitaxel, is a new observation which has not been reported previously. The recommended dose for phase II study is 210 mg/m2 . Although hypotension was observed as an unexpected toxic effect, paclitaxel could be administered safely over 3 h with premedication and proper monitoring, resulting in reduced myelotoxicity and with no increase in the incidence of HSRs as compared with a 24-h infusion. 相似文献
17.
Paediatric cardiac arrest and resuscitation provided by physician-staffed emergency care units 总被引:1,自引:0,他引:1
P. SUOMINEN R. KORPELA M. KUISMA T. SILFVAST K. T. OLKKOLA 《Acta anaesthesiologica Scandinavica》1997,41(2):260-265
Background: Most paediatric cardiac arrest studies have been conducted in the USA, where paramedics provide prehospital emergency care. We wanted to study the outcome of paediatric cardiac arrest patients in an emergency medical system which is based on physician staffed emergency care units.
Methods: We analysed retrospectively the files of 100 prehospital cardiac arrest patients from Southern Finland during a 10-year study period. The patients were less than 16 years of age.
Results: Fifty patients were declared dead on the scene (DOS) without attempted resuscitation, and cardiopulmonary resuscitation (CPR) was initiated in 50 patients. The sudden infant death syndrome was the most common cause of arrest in the DOS patients (68%) as well as in those receiving CPR (36%). Asystole was the initial cardiac rhythm in 70% of the patients in whom CPR was attempted. Resuscitation was successful in 13 patients, 8 of whom were ultimately discharged. Six of the patients survived with mild or no disability and 4 of them had near-drowning aetiology. In multivariate analysis, the short duration of CPR (≤15 min) was the only factor significantly associated with better survival.
Conclusions: Although prehospital care was provided by physicians, the overall rate of survival was found to be equally poor as reported from systems with paramedics. The only major difference between physician- and paramedic-staffed emergency care units is the ability of physicians to refrain from resuscitation already on the scene when prognosis is poor. 相似文献
Methods: We analysed retrospectively the files of 100 prehospital cardiac arrest patients from Southern Finland during a 10-year study period. The patients were less than 16 years of age.
Results: Fifty patients were declared dead on the scene (DOS) without attempted resuscitation, and cardiopulmonary resuscitation (CPR) was initiated in 50 patients. The sudden infant death syndrome was the most common cause of arrest in the DOS patients (68%) as well as in those receiving CPR (36%). Asystole was the initial cardiac rhythm in 70% of the patients in whom CPR was attempted. Resuscitation was successful in 13 patients, 8 of whom were ultimately discharged. Six of the patients survived with mild or no disability and 4 of them had near-drowning aetiology. In multivariate analysis, the short duration of CPR (≤15 min) was the only factor significantly associated with better survival.
Conclusions: Although prehospital care was provided by physicians, the overall rate of survival was found to be equally poor as reported from systems with paramedics. The only major difference between physician- and paramedic-staffed emergency care units is the ability of physicians to refrain from resuscitation already on the scene when prognosis is poor. 相似文献
18.
Anders Franco-Cereceda 《Naunyn-Schmiedeberg's archives of pharmacology》1989,340(2):180-184
Summary (1) The possible influence of Prostaglandins (PG) E1 and I2 as well as ischaemia, ouabain and bradykinin on the outflow of calcitonin gene-related peptide (CGRP)- and neuropeptide Y (NPY)-like immunoreactivity (LI) from the guinea-pig heart was studied in vitro. (2) Exposure to PGE1 (10–5 M), but not PGI2 (10–5 M), induced an increased outflow, suggesting release of CGRP-LI. PGE1 simultaneously increased the contractile force and heart rate while no effects were observed on perfusate volume or outflow of NPY-LI. PGI2 had no effect on contractile parameters or coronary flow. In separate experiments on capsaicin-pretreated animals, the stimulatory effects of PGE1 on heart rate and contractile force remained unchanged while no increased CGRP-LI outflow was detectable. (3) Ouabain, bradykinin and reperfusion after total stop-flow ischaemia was associated with an indomethacin-resistant increase in perfusate levels of CGRP-LI but not of NPY-LI. While ouabain markedly increased the contractile force, exposure to bradykinin or ischaemia did not induce any clear-cut changes in contractile force or heart rate. (4) Capsaicin-exposure evoked a markedly increased outflow of CGRP-LI but not of NPY-LI in combination with an increase in heart rate and a decrease in contractile force. Repeated administration of capsaicin induced tachyphylaxis. The stimulatory effects of capsaicin on CGRP-LI outflow and heart rate, but not the negative inotropic effect, did not occur in capsaicin-pretreated animals. (5) It is concluded that PGE1, but not PGI2, can activate cardiac capsaicin-sensitive fibres as revealed by increased outflow of CGRP-LI. The cardiostimulatory effects induced by PGE1 are not related to CGRP release, however. A possible prostaglandin link in the CGRP-LI released by ouabain, bradykinin or ischaemia seems unlikely.
Send offprint requests to: A. Franco-Cereceda at the above address 相似文献
19.
Elena del Olmo Carmen del Arco Alvaro Díaz Julio Pascual Guadalupe Mengod José M. Palacios Angel Pazos 《The European journal of neuroscience》1996,8(1):53-60
The pattern of pre- and postnatal appearance of 5-HT1D receptors throughout the different areas of the human brain was studied by quantitative in vitro autoradiography, using [125 I]GTI (serotonin O -carboxymethyl-glycyl-[125 I]tyrosinamide) as a ligand. The anatomical distribution of 5-HT1D receptors in neonatal, infant and children's brain was in good agreement with that observed in the adult, the basal ganglia and substantia nigra being the most intensely labelled areas. The development of these receptors throughout the human brain was mainly postnatal: low densities of [125 I]GTI binding sites were observed at the fetal/neonatal stage in most regions analyzed, in contrast with the high levels of labelling found in infant and children's brains. Indeed, in a number of regions, including the globus pallidus, substantia nigra and visual cortex, a peak of overexpression of 5-HT1D receptors was observed in the first decade of life. Such overexpression could support a regulatory role for 5-HT1D receptors in advanced periods of the CNS developmental process. Our results also indicate that the administration of drugs acting on 5-HT1D receptors during the early postnatal period of life could result in modifications of their properties, as these receptors are already functional in this period. 相似文献
20.