全文获取类型
收费全文 | 6458篇 |
免费 | 751篇 |
国内免费 | 16篇 |
专业分类
耳鼻咽喉 | 88篇 |
儿科学 | 192篇 |
妇产科学 | 178篇 |
基础医学 | 780篇 |
口腔科学 | 175篇 |
临床医学 | 605篇 |
内科学 | 1429篇 |
皮肤病学 | 189篇 |
神经病学 | 373篇 |
特种医学 | 353篇 |
外科学 | 1032篇 |
综合类 | 223篇 |
一般理论 | 4篇 |
预防医学 | 588篇 |
眼科学 | 150篇 |
药学 | 336篇 |
中国医学 | 2篇 |
肿瘤学 | 528篇 |
出版年
2021年 | 75篇 |
2019年 | 86篇 |
2018年 | 62篇 |
2017年 | 60篇 |
2016年 | 68篇 |
2015年 | 94篇 |
2014年 | 136篇 |
2013年 | 204篇 |
2012年 | 277篇 |
2011年 | 249篇 |
2010年 | 164篇 |
2009年 | 164篇 |
2008年 | 252篇 |
2007年 | 263篇 |
2006年 | 248篇 |
2005年 | 287篇 |
2004年 | 261篇 |
2003年 | 261篇 |
2002年 | 209篇 |
2001年 | 173篇 |
2000年 | 183篇 |
1999年 | 176篇 |
1998年 | 103篇 |
1997年 | 99篇 |
1996年 | 96篇 |
1995年 | 82篇 |
1994年 | 77篇 |
1993年 | 69篇 |
1992年 | 156篇 |
1991年 | 123篇 |
1990年 | 120篇 |
1989年 | 117篇 |
1988年 | 138篇 |
1987年 | 102篇 |
1986年 | 100篇 |
1985年 | 94篇 |
1984年 | 90篇 |
1983年 | 125篇 |
1982年 | 102篇 |
1981年 | 79篇 |
1980年 | 84篇 |
1979年 | 88篇 |
1978年 | 78篇 |
1977年 | 77篇 |
1976年 | 93篇 |
1975年 | 72篇 |
1974年 | 64篇 |
1973年 | 66篇 |
1971年 | 70篇 |
1970年 | 57篇 |
排序方式: 共有7225条查询结果,搜索用时 31 毫秒
51.
52.
D I Ben-Tovim N Subbiah B Scheutz J Morton 《The Australian and New Zealand journal of psychiatry》1989,23(1):73-80
The widely used DSM-III criteria for the diagnosis of bulimia essentially define bulimia as a syndrome of guilty, secretive and subjectively hard to control binge over-eating. A self-report questionnaire for bulimic behavior was administered to three community and two hospital populations in South Australia. 13% of females in the community samples could be categorized as bulimic according to the DSM-III criteria. Those criteria did not adequately define the behaviour of patients in treatment for bulimia in a Weight Disorders Unit, 85% of whom not only binged, but induced vomiting afterwards. When diagnostic criteria were more closely aligned to clinical experience, the prevalence of bulimia in the community appeared closer to 1-2%. New DSM criteria (DSM-III-R) have been proposed and prevalence rates using them fell within the 1-2% range. 相似文献
53.
Somatostatin: evidence for a role in thermal nociception 总被引:5,自引:0,他引:5
In barbiturate-anaesthetized spinalized cats, antibody microprobes were used to investigate the release of immunoreactive somatostatin (irSS) in the lumbar dorsal horn in response to cutaneous stimuli. In the absence of applied stimulation, a significant basal release of irSS was present in the region of the substantia gelatinosa. Such release was not increased by innocuous or noxious cutaneous mechanical stimuli nor by innocuous thermal stimuli, but was increased by noxious thermal stimulation. The magnitude of this noxious heat-evoked release was estimated by comparing in vivo microprobes with those used to detect known concentrations of somatostatin in vitro. Pairs of microprobes were used to detect simultaneous release of both irSS and immunoreactive substance P in the substantia gelatinosa. The results support the putative role of somatostatin in the spinal transmission of thermal nociceptive information. 相似文献
54.
55.
Steven Mlynarek Morton Corn Charles Blake 《Regulatory toxicology and pharmacology : RTP》1996,23(3):213-224
The exposures of building maintenance personnel and occupants to airborne asbestos fibers, and the effects of operations and maintenance programs on those exposures, continue to be an important public health issue. The subject of this investigation was a large metropolitan county with numerous public buildings which routinely conducted air sampling for asbestos. A total of 302 personal air samples in nine task categories collected during maintenance worker activities in proximity to asbestos-containing materials were analyzed; 102 environmental air samples in four task categories were also analyzed. The arithmetic means of the 8-hr time weighted average exposures for personal sampling for each task category were all below the Occupational Safety and Health Administration permissible exposure level of 0.1 fibers (f)/cc > 5 μm. The highest mean 8-hr time weighted average exposure was 0.030 f/cc > 5 μm for ceiling tile replacement. The maximum asbestos concentration during sample collection for environmental samples was 0.027 f/cc > 5 μm. All asbestos-related maintenance work was done within the framework of an Operations and Maintenance Program (OMP) which utilized both personal protective equipment and controls against fiber release/dispersion. Results are presented in association with specific OMP procedures or controls. These results support the effectiveness of using Operations and Maintenance Programs to manage asbestos in buildings without incurring unacceptable risk to maintenance workers performing maintenance tasks. 相似文献
56.
W. Bastain M. J. Boyce L. E. Stafford P. B. Morton D. A. Clarke H. F. Marlow 《European journal of clinical pharmacology》1988,34(5):469-473
Summary The pharmacokinetics of xamoterol, a -adrenoceptor partial agonist under clinical evaluation for the treatment of mild to moderate heart failure, have been studied in 12 healthy male subjects. They received 14 mg i.v. and oral doses of 50 and 200 mg as a tablet and 200 mg as a solution in a 4 way cross-over design.After i.v. dosing the elimination half-life was 7.7 h, the total body clearance was 224 ml·min–1 and the volume of distribution at steady-state (Vss) was 48 l. Sixty-two percent of the dose was recovered unchanged in urine. After oral doses, the absolute bioavailability of xamoterol was shown to be 5% irrespective of whether the dose was administered as a tablet or solution. Peak plasma concentrations occurred at about 2 h for the tablet dose and slightly earlier (1.4 h) for the solution. Peak plasma concentration, AUC and urinary recovery of unchanged drug increased in proportion to dose. The apparent elimination half-life after oral doses (16 h) was significantly longer than that observed after an intravenous dose.Despite the low bioavailability, the degree of inter-subject variability of oral bioavailability was small probably indicating that the controlling factor is the hydrophilic nature of the molecule rather than extensive first pass metabolism or poor dissolution of xamoterol from the tablet formulation. 相似文献
57.
Angelo Ferrara M.D. Ph.D. Melvin Schwartz M.D. Helen Page R.N. M.P.A. Morton Israel M.A. Yucel Atakent M.D. M.S. C. E. Smith Ph.D. Leon Landovitz Ph.D. 《Journal of community health》1988,13(1):3-18
In the past two decades, there has been a gradual trend to regionalization of perinatal care, categorization of hospitals and transport services for neonatal health care. The literature alludes to both beneficial and deleterious effects of neonatal transport (T) but no controls such as a matched nontransport (NT) population have been utilized to date.The major goal of this study was to evaluate the effect of neonatal transport from Level I and II high risk 2500 gm. neonates (born in NYC in one calendar year, 1979) compared to a cohort nontransported population matched for hospital of birth, weight, race, sex and risk. All transported 2500 gm. from Level I and II (n=328) were studied and a stratified random sample of the nontransported (NT) infants 2500 gm. from these same hospitals (n=2042) was used for comparison. The principle outcome variable was survival. The major conclusion of this study is that in Level I and II hospitals the transport group had a significantly increased survival in infants who were sick (Apgar <6) compared to cohorted nontransported controls. Interhospital differences in survival were noted among Level I and II but not seen in the subdivisions of (A) and (B) hospitals.Angelo Ferrara, M.D., Ph.D., is Professor, Pediatrics, NYU Medical Center, New York, N.Y.: Melvin Schwartz, M.D., was Research Professor, Environmental Medicine, NYU Medical Center, New York, N.Y.; Helen Page, R.N., M.P.A., is Quality Assurance Reviewer, Manhattan Eye, Ear, Throat Hospital, New York, N.Y.: Morton Israel, M.A., is Research Scientist, Health Resources Administration, City of N. Y., New York, N.Y.; Yucel Atakent, M.D., M.S., is Clinical Associate Professor, NYU Medical Center, New York, N.Y.; C.E. Smith, Ph.D., is President, Health Policy Analysis & Accountability Network, Inc. (HPAAN), Edgewood, New Mexico; Leon Landovitz, Ph.D., is Vice President, Management Information Systems, Healthways System Inc., Islin, N.J.Supported by NCHSR Grant #5-R018-HSO3832 相似文献
58.
Biological responses to overload training in endurance sports 总被引:2,自引:0,他引:2
Rod W. Fry Alan R. Morton Peter Garcia-Webb G P M Crawford David Keast 《European journal of applied physiology》1992,64(4):335-344
Summary Five subjects undertook 10 days of twice daily interval training sessions on a treadmill followed by 5 days of active recovery. On days 1, 6, 11, and 16 the subjects were required to undertake a test of submaximal and maximal work capacity on a treadmill combined with a performance test consisting of a run to exhaustion with the treadmill set at 18 km · h–1 and 1% gradient. Also on these days a pre-exercise blood sample was collected and analysed for a range of haematological, biochemical and immunological parameters. The subjects experienced a significant fall in performance on day 11 which had returned to pretraining levels on day 16. Serum ferritin concentrations were depressed significantly from pretraining concentrations at the conclusion of the recovery period while the expression of lymphocyte activation antigens (CD25+ and HLA-DR+) was increased both after the training phase and the recovery phase. The number of CD56+ cells in the peripheral circulation was depressed at the conclusion of the recovery period. Several parameters previously reported to change in association with overload training failing to reflect the decrease in performance experienced by subjects in this study, suggesting that overtraining may best be diagnosed through a multifactorial approach to the recognition of symptoms. The most important factor to consider may be a decrease in the level of performance following a regeneration period. The magnitude of this decreased performance necessary for the diagnosis of overtraining and the nature of an appropriate regeneration period are, however, difficult to define and may vary depending upon the training background of the subjects and the nature of the preceding training. It may or may not be associated with biochemical, haematological, physiological and immunological indicators. Individual cases may present a different range of symptoms and diagnosis of overtraining should not be excluded based on the failure of blood parameters to demonstrate variation. However, blood parameters may be useful to identify possible aetiology in each separate case report of overtraining. An outstanding factor to emerge from this study was the difficulty associated with an objective diagnosis of overtraining and this is a possible reason why there have been new accounts of overtraining research in the literature. 相似文献
59.
Bernard A. MacLeod Roy McGroarty Roy H. Morton Michael J. A. Walker 《Journal canadien d'anesthésie》1989,36(3):289-294
The effect of halothane on arrhythmias induced by ischaemia was investigated in rats, isolated perfused rat hearts, and pigs. Responses to the occlusion of the left anterior descending coronary artery were determined in groups (n = 9) of chronically prepared rats treated with no halothane, 0.5, or 1.0 per cent halothane immediately after occlusion; in isolated rat hearts (n = 10) treated with no halothane, 0.5, 1.0, 2.0, or 4.0 per cent halothane for 15 min before and after occlusion; and 20–25 kg pigs (n = 11) anaesthetised with halothane or pentobarbital. The ECG, arrhythmias, blood pressure (BP), heart rate (HR) and extent of infarction were determined in each model. In pigs, left ventricular pressure, dp/dtmax and cardiac output were also measured. In chronically prepared rats, halothane anaesthesia started after occlusion was antiarrhythmic and decreased the incidence of ventricular fibrillation and resulting mortality. In isolated rat hearts, 0.5 or 1.0 per cent halothane had little effect on occlusion-induced arrhythmias. The highest concentration of halothane increased the incidence of ventricular fibrillation both before and after occlusion. Halothane decreased developed ventricular pressure in a dose-dependent manner. In acutely prepared pigs, halothane pre-treatment had no appreciable effect upon occlusion-induced arrhythmias when compared with pentobarbital anaesthesia. Thus, halothane is antiarrhythmic when treatment is initiated after occlusion in the rat but this action is not seen in isolated hearts or intact pigs. The antiarrhythmic action of halothane is, therefore, species and model dependent. 相似文献
60.