全文获取类型
收费全文 | 11015篇 |
免费 | 756篇 |
国内免费 | 80篇 |
专业分类
耳鼻咽喉 | 92篇 |
儿科学 | 159篇 |
妇产科学 | 143篇 |
基础医学 | 1756篇 |
口腔科学 | 203篇 |
临床医学 | 1028篇 |
内科学 | 2380篇 |
皮肤病学 | 170篇 |
神经病学 | 1138篇 |
特种医学 | 443篇 |
外科学 | 1656篇 |
综合类 | 132篇 |
现状与发展 | 1篇 |
一般理论 | 5篇 |
预防医学 | 639篇 |
眼科学 | 319篇 |
药学 | 772篇 |
3篇 | |
中国医学 | 25篇 |
肿瘤学 | 787篇 |
出版年
2024年 | 27篇 |
2023年 | 95篇 |
2022年 | 279篇 |
2021年 | 453篇 |
2020年 | 230篇 |
2019年 | 244篇 |
2018年 | 349篇 |
2017年 | 222篇 |
2016年 | 272篇 |
2015年 | 349篇 |
2014年 | 428篇 |
2013年 | 542篇 |
2012年 | 804篇 |
2011年 | 901篇 |
2010年 | 475篇 |
2009年 | 442篇 |
2008年 | 705篇 |
2007年 | 689篇 |
2006年 | 646篇 |
2005年 | 651篇 |
2004年 | 558篇 |
2003年 | 533篇 |
2002年 | 490篇 |
2001年 | 75篇 |
2000年 | 54篇 |
1999年 | 74篇 |
1998年 | 94篇 |
1997年 | 86篇 |
1996年 | 59篇 |
1995年 | 53篇 |
1994年 | 60篇 |
1993年 | 49篇 |
1992年 | 32篇 |
1991年 | 37篇 |
1990年 | 32篇 |
1989年 | 27篇 |
1988年 | 29篇 |
1986年 | 25篇 |
1985年 | 26篇 |
1984年 | 34篇 |
1983年 | 36篇 |
1982年 | 46篇 |
1981年 | 43篇 |
1980年 | 49篇 |
1979年 | 36篇 |
1978年 | 33篇 |
1977年 | 33篇 |
1976年 | 31篇 |
1975年 | 28篇 |
1974年 | 25篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Rektor I Goldemund D Sheardová K Rektorová I Michálková Z Dufek M 《Parkinsonism & related disorders》2009,15(1):24-29
To study the impact of brain vessel pathology on the clinical status of Parkinson's disease (PD), in 57 consecutive patients the clinical and neuropsychological data were compared with clinical MRI signs of vascular impairment and with the ultrasound brain vessel investigations. There was a significant correlation between clinical and cognitive status and intimomedial thickness, which is an indicator of large vessel impairment. Cognitive status was significantly related to the pulsatility index (an indicator of small vessel impairment). This study provides evidence that subclinical vascular pathology could influence the clinical status by contributing to motor and cognitive dysfunction in PD. 相似文献
992.
993.
Wasmeier GH Melnychenko I Voigt JU Zimmermann WH Eschenhagen T Schineis N Reulbach U Flachskampf FA Daniel WG Nixdorff U 《Coronary artery disease》2007,18(4):283-291
OBJECTIVE: Transthoracic echocardiography has been employed to assess left ventricular dimensions and function in small animals. The aim of this study was to identify the limits of transthoracic echocardiography in a commonly used Wistar rat model by assessing intraobserver variability, interobserver variability, and day-to-day variability of examinations implying registrations and measurements. METHODS: Twenty male adult Wistar rats (body weight 496+/-52 g) were examined under volatile isoflurane anesthesia (heart rate 302+/-26 bpm) by transthoracic echocardiography (Sonos 7500; Philips) with a 15 MHz-transducer. For calculation of intraobserver variability, examinations were repeated by the same examiner and for interobserver variability, examinations were performed independently by two investigators. For day-to-day variability, examinations were repeated 14 days later. Left ventricular diameters and areas were analyzed in parasternal short axis and in a modified parasternal long axis. Fractional shortening, area shortening, ejection fraction, stroke volume, and cardiac output were calculated. RESULTS: Left ventricular end-diastolic diameter was 8.9+/-0.6 mm, fractional shortening 39.0+/-5.3%, area shortening 59.6+/-6.1%, ejection fraction 83.3+/-5.1%, stroke volume 0.24+/-0.06 ml, and cardiac output 72.9+/-20.6 ml/min. Intraobserver variability of left ventricular end-diastolic diameter, fractional shortening, area shortening, and ejection fraction was less than 10%, increasing to 19% for stroke volume and cardiac output. Interobserver variability of left ventricular end-diastolic diameter, fractional shortening, area shortening, ejection fraction was less than 13%, increasing to 23% for stroke volume and 25% for cardiac output. Day-to-day variability of left ventricular end-diastolic diameter, area shortening, ejection fraction was less than 11% whereas for stroke volume it was 21% and for cardiac output it was 22%. F-ratio test comparing investigated variabilities did not reveal significant differences. CONCLUSIONS: M-mode and two-dimensional echocardiography in large rats by clinically common high-end ultrasound systems can be assessed reliably. Parameters of global left ventricular performance like stroke volume and cardiac output could not be assessed with similar reliability. 相似文献
994.
995.
996.
997.
Leposavić G Radojević K Vidić-Danković B Kosec D Pilipović I Perisić M 《Journal of neuroimmunology》2007,182(1-2):100-115
The interactions among the nervous, endocrine and immune system were studied by examining: i) thymic and thymocyte catecholamine levels in adult rats castrated (Cx) at postnatal day 3 and ii) effects of 14-day-long propranolol (P) treatment on main thymocyte differentiational molecule expression in adult non-Cx and Cx rat. The results demonstrated that castration in early postnatal period lowers levels of both neurally- and thymocyte-derived noradrenaline in adult rats, and thereby diminishes beta-adrenoceptor-mediated fine tuning of the T-cell differentiation/maturation. In non-Cx rats P affected TCRalphabeta-dependent stages of thymocyte differentiation/maturation decreasing frequency of CD4+8+ double positive (DP) TCRalphabeta(low) cells entering selection processes and increasing relative number of positively selected DP TCRalphabeta(high) (most likely due to an increased thymocyte surface density of Thy-1 that is involved in negative control of TCRalphabeta-mediated signaling/selection thresholds) and the most mature CD4+8- TCRalphabeta(high) cells (including CD4+25+ regulatory cells). However, in Cx rats P failed to produce any significant changes in thymocyte subset composition. 相似文献
998.
999.
The role of the father in the onset and development of schizophrenic disorder/disturbance is very often secondary as compared to that of the mother. This study deals with the father's sphere in the family with a patient/son suffering from schizophrenia, the traits of his personality and his relationship with his son/patient, and with his wife/the mother of the patient. The methods applied were clinical interview, structured interview and semantic differential. The following statistical procedures were used: correlation, componential, discriminative, factor and quasicanonical analyses. The results include some characteristic excerpts from clinical interviews with patients/sons and their fathers, projective perception of current family relationships, quasicanonical analysis of the father's, mother's and son's experiences of the patient's/son's early childhood, and the projective view of the father. Among the conclusions reached, the phenomenon of "dead father" is emphasized as one of the main factors in the onset and development of schizophrenic disorder/disturbance. 相似文献
1000.
Buznikov GA Nikitina LA Rakić LM Milosević I Bezuglov VV Lauder JM Slotkin TA 《Brain research bulletin》2007,74(4):221-231
Lower organisms show promise for the screening of neurotoxicants that might target mammalian brain development. Sea urchins use neurotransmitters as embryonic growth regulatory signals, so that adverse effects on neural substrates for mammalian brain development can be studied in this simple organism. We compared the effects of the organophosphate insecticide, chlorpyrifos in sea urchin embryos with those of the monoamine depleter, reserpine, so as to investigate multiple neurotransmitter mechanisms involved in developmental toxicity and to evaluate different therapeutic interventions corresponding to each neurotransmitter system. Whereas reserpine interfered with all stages of embryonic development, the effects of chlorpyrifos did not emerge until the mid-blastula stage. After that point, the effects of the two agents were similar. Treatment with membrane permeable analogs of the monoamine neurotransmitters, serotonin and dopamine, prevented the adverse effects of either chlorpyrifos or reserpine, despite the fact that chlorpyrifos works simultaneously through actions on acetylcholine, monoamines and other neurotransmitter pathways. This suggests that different neurotransmitters, converging on the same downstream signaling events, could work together or in parallel to offset the developmental disruption caused by exposure to disparate agents. We tested this hypothesis by evaluating membrane permeable analogs of acetylcholine and cannabinoids, both of which proved effective against chlorpyrifos- or reserpine-induced teratogenesis. Invertebrate test systems can provide both a screening procedure for mammalian neuroteratogenesis and may uncover novel mechanisms underlying developmental vulnerability as well as possible therapeutic approaches to prevent teratogenesis. 相似文献