首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   37081篇
  免费   2896篇
  国内免费   717篇
耳鼻咽喉   145篇
儿科学   827篇
妇产科学   363篇
基础医学   2586篇
口腔科学   907篇
临床医学   3737篇
内科学   4449篇
皮肤病学   268篇
神经病学   3157篇
特种医学   569篇
外科学   1896篇
综合类   5409篇
现状与发展   1篇
一般理论   1篇
预防医学   8412篇
眼科学   264篇
药学   3018篇
  49篇
中国医学   3182篇
肿瘤学   1454篇
  2024年   122篇
  2023年   643篇
  2022年   1154篇
  2021年   1634篇
  2020年   1481篇
  2019年   1604篇
  2018年   1409篇
  2017年   1360篇
  2016年   1309篇
  2015年   1198篇
  2014年   2456篇
  2013年   2556篇
  2012年   2383篇
  2011年   2497篇
  2010年   2095篇
  2009年   1884篇
  2008年   1907篇
  2007年   1883篇
  2006年   1428篇
  2005年   1230篇
  2004年   1021篇
  2003年   974篇
  2002年   713篇
  2001年   634篇
  2000年   587篇
  1999年   527篇
  1998年   413篇
  1997年   417篇
  1996年   357篇
  1995年   328篇
  1994年   275篇
  1993年   233篇
  1992年   218篇
  1991年   188篇
  1990年   148篇
  1989年   139篇
  1988年   146篇
  1987年   107篇
  1986年   95篇
  1985年   158篇
  1984年   134篇
  1983年   99篇
  1982年   101篇
  1981年   89篇
  1980年   72篇
  1979年   70篇
  1978年   46篇
  1977年   31篇
  1976年   32篇
  1975年   26篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
73.
74.
A patient is described with the bird-egg syndrome who experienced an anaphylactic reaction after eating some of her parrot's food (pine nuts: Pinus pinea ). Specific IgE against this nut and another pine nut ( P cembra ) was demonstrated by RAST. Cross-reactivity between these botanically related seeds was shown by RAST inhibition. Besides avian antigens, bird food antigens should be taken into consideration when symptoms of allergy occur on exposure to birds.  相似文献   
75.
The current source-density (CSD) analysis was used to investigate the organization of tangential synaptic connections in primary visual cortex of normally reared (NR) kittens and of NR, binocularly deprived (BD) and dark-reared (DR) adult cats. Laminar profiles of field potentials, elicited by intracortical microstimulation were measured at various distances from the stimulating electrodes. To exclude contamination by axon collaterals of antidromically stimulated thalamo-cortical fibres, these were destroyed by injecting the cytotoxin N-methyl-D-aspartate (NMDA) into the lateral geniculate nucleus 13 - 27 days before recording. The CSD profiles revealed distinct layer-specific patterns of lateral spread of activity. Invariably, the most prominent, long-lasting and far reaching responses were recorded in supragranular layers. Responses in layer IV were brief and confined to the vicinity of the stimulation site. Responses in infragranular layers spread as far as those in supragranular layers, but were of smaller amplitude. Latency considerations, the results of double shock stimulation, and the effects of translaminar cuts, suggest that these responses were monosynaptic and mediated by intracortical pathways with a conduction velocity of 0.3-5 m/s. The spatial spread of these responses changed substantially with age but was not influenced by visual deprivation. In NR adults, supra- and infragranular responses were recordable up to 2.5 mm from the stimulation site and layer IV responses up to 1 mm from the stimulation site. In kittens, the former responses spread up to 5 mm and the latter up to 2 mm from the site of stimulation. The amplitude of the responses decreased with distance from the stimulation site. This decrease was not always monotonic suggesting inhomogeneities in the tangential projections. The laminar distribution of current sinks and sources indicates that the pathways mediating tangential interactions form excitatory synapses on apical dendrites of pyramidal cells. It is concluded that the spatial spread of tangential excitatory interactions decreases with age, but that neither the laminar pattern nor the age-dependent reduction in the strength of tangential interactions are influenced by visual deprivation.  相似文献   
76.
A multivariate analysis was performed to assess the effect of post-relapse systemic therapy on a series of patients with metastatic breast cancer who at initial presentation had no detectable metastases (M), were 70 years of age, presented with unilateral localized disease and no other associated malignancy, and were treated between 1965 and 1984 with successive protocols for primary disease and subsequently developed distant metastasis. All 760 patients analyzed relapsed with at least one metastasis, and were studied retrospectively with no selection criteria according to any specific protocol. All had recorded clinical data on menopause, stage, clinical tumor aggressiveness (PEV), initial chemo or hormonal therapy, and time to relapse, and had ongoing follow up at our Center, with salvage chemotherapy and/or hormonal therapy having been given to some but not all patients.A brief metastasis-free survival (p < 0.000001), and factors associated with electing pre-relapse chemotherapy (p < 0.000001) were associated with shortened post-relapse survival, while post-relapse therapy (chemo p < 0.0001, and hormonal p < 0.00001, replacing chemotherapy in the model) apparently increased post-relapse survival in the group overall. This result was similar in the inoperable patient group [with inflammatory breast carcinoma an additional risk factor (p < 0.0005)], as well as the operable group. However, in the operable group, when the pathologic criteria of histologic grade and nodal status were introduced into the analysis, post-relapse therapy was not seen to be an important factor for survival in any subgroup. Histograde (p < 0.000001), nodal status (p < 0.0001), metastasis-free survival (p < 0.001), and menopausal status (p = 0.03) were the only significant factors for post-relapse survival.  相似文献   
77.
汉·张仲景著《伤寒论》中辨证论治体系也包括外治法的内容 ,《伤寒论》中的外治法有针、灸、温覆、熏、导、温粉等治疗方法 ,在临床上用于解表、泻下、和解、清热、温里、固涩、祛湿、预防传变等若干方面。  相似文献   
78.
79.
The rationale and methodology behind the Australian Quality Assurance Project is described. The Project aimed to develop guidelines for treatment content based on three sources of information: research findings, current practice and expert opinion. The issue of the gap between research and practice is discussed, as well as the role of dissemination in altering clinician behaviour.  相似文献   
80.
In sheep cardiac Purkinje fibers concentration-dependent inhibition of transient outward current (ito) by 4-aminopyridine (4-AP, 3-1000 mol/l) was recorded with the two-microelectrode voltage-clamp technique, and correlated effects on action potential duration measured at — 70 mV (APD-70) were investigatigated.Half-maximal inhibition of ito-amplitude occurred at 15 mol/l 4-AP. The drug exhibited no major effect on voltage-dependent control of inactivation but reduced the maximally available ito-current. At different activation frequencies (0.05 Hz, 0.25 Hz, 1 Hz) an equal amount of ito-current, measured as percentage of the respective control, was inhibited by 4-AP. The APD-70 was on the average increased by 4-AP (3–500 mol/l) in a concentration-dependont manner up to 151 % of control. The drug-induced prolongation, measured as percentage of the respective control, was independent of stimulation frequency (0.05 Hz, 0.25 Hz, 1 Hz). Prolongation of APD-70 was on the average more pronounced for short action potentials (APD-70<150 ms: 169 % of reference) than for longer ones (APD-70 150–300 ms: prolongation to 117 % of reference; 500 mol/l 4-AP; 0.25 Hz stimulation rate). Few long control signals (APD-70 >300 ms) were shortened by 4-AP. These results indicate that inhibition of ito-current by appropriate drugs will result in a reduction of inhomogeneity of action potential duration.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号