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   67724篇
  免费   7590篇
  国内免费   4826篇
耳鼻咽喉   512篇
儿科学   701篇
妇产科学   1303篇
基础医学   7459篇
口腔科学   1229篇
临床医学   11387篇
内科学   10320篇
皮肤病学   632篇
神经病学   3718篇
特种医学   2283篇
外国民族医学   52篇
外科学   6631篇
综合类   11343篇
现状与发展   19篇
一般理论   5篇
预防医学   4739篇
眼科学   1892篇
药学   7002篇
  41篇
中国医学   3530篇
肿瘤学   5342篇
  2024年   290篇
  2023年   1358篇
  2022年   2785篇
  2021年   3521篇
  2020年   2748篇
  2019年   2303篇
  2018年   2443篇
  2017年   2341篇
  2016年   2263篇
  2015年   3243篇
  2014年   4018篇
  2013年   3509篇
  2012年   5024篇
  2011年   5504篇
  2010年   3349篇
  2009年   2779篇
  2008年   3549篇
  2007年   3366篇
  2006年   3312篇
  2005年   3235篇
  2004年   2155篇
  2003年   2068篇
  2002年   1716篇
  2001年   1486篇
  2000年   1482篇
  1999年   1755篇
  1998年   1121篇
  1997年   1087篇
  1996年   816篇
  1995年   757篇
  1994年   722篇
  1993年   449篇
  1992年   616篇
  1991年   486篇
  1990年   449篇
  1989年   362篇
  1988年   344篇
  1987年   279篇
  1986年   237篇
  1985年   216篇
  1984年   117篇
  1983年   86篇
  1982年   63篇
  1981年   59篇
  1980年   32篇
  1979年   52篇
  1978年   29篇
  1977年   21篇
  1976年   17篇
  1975年   10篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
脊柱侧弯是青少年的多发病,发病率约1%,不但影响美观,也给患者心理健康造成危害,而且严重影响患者的心肺功能,甚至导致截瘫,目前最好的治疗方法是早期手术.  相似文献   
32.
Effects of stimulation of brainstem sites on hemodynamics and plasma catecholamine levels were assessed in cats under chloralose-urethane anesthesia. Pressor areas of the dorsal medulla (DM) and ventrolateral medulla (VLM) and the depressor area of the paramedian reticular nucleus (PRN) were stimulated electrically using a monopolar electrode, or chemically using sodium glutamate microinjection. Plasma levels of norepinephrine (NE) and epinephrine (EPI) were measured in caval blood above the adrenal veins. Electrical stimulation of the DM and VLM produced increases in blood pressure and in plasma NE and EPI levels that were enhanced after acute vagotomies. The NE and EPI responses were attenuated after acute, bilateral adrenalectomies, confirming augmented adrenomedullary secretion, whereas the pressor responses were intact. Injection of sodium glutamate into the same pressor regions of the DM or VLM also produced pressor responses and elevated plasma catecholamine levels, indicating that the responses resulted from activation of neuronal perikarya. Stimulation of the PRN attenuated pressor and catecholamine responses during stimulation of the DM and VLM. The results indicate that pressor responses during stimulation of the DM and VLM are due at least partly to activation of perikarya in these regions, are associated with but not dependent on adrenomedullary activation, and are enhanced after vagotomy; and that neurons of the PRN exert inhibitory modulation of the pressor and adrenomedullary responses during stimulation of VLM and DM.  相似文献   
33.
M Ma  H Hu  F Kutlar  J B Wilson  T H Huisman 《Hemoglobin》1987,11(5):473-479
A slow-moving gamma chain variant was discovered in the cord blood of an infant born to parents of the Han nationality from Jiangsu. The variant, which migrated electrophoretically at alkaline pH between Hb A and Hb D, was characterized by an Asp----His substitution at gamma 73, while residues gamma 75 and gamma 136 were occupied by Ile and Ala, respectively. As the A gamma T-chain was also present, this baby has two types of abnormal gamma-chain. The variant was named Hb F-Xin-Su.  相似文献   
34.
Chronic lead exposure may cause hypertension in normotensive rats. This hypertensinogenic effect has been attributed to perturbations in the renin-angiotensin axis, the contractile response of the vascular smooth muscle, or the intracellular Ca2+ homeostasis as a consequence of the inhibition of Na(+)-K(+)-ATPase activity. In this study we examined the short-term effect of lead exposure on blood pressure, plasma renin activity, vascular contractility, and renal Na(+)-K(+)-ATPase activity and abundance in the spontaneously hypertensive rat. Our data indicate that modest lead exposure caused blood pressure elevation within two weeks in this rat strain that is genetically susceptible to the development of hypertension. This rapid blood pressure-elevating effect did not appear to depend on the mechanisms described in hypertension associated with more chronic lead exposure listed above. This acute model provides an additional approach to the study of lead-induced hypertension.  相似文献   
35.
为探索天然超氧化物岐化酶(SOD)岐化超氧离子的机理,及用于临床的可能性,我们合成了乳酸、柠檬酸和酒石酸的锰(Ⅱ)配合物作为Mn-SOD的模拟物,用光照法测定了它们的活性,得到了有意义的结果:锰配合物作为Mn-SOD的模拟物,有肯定的活性,其中以乳酸锰配合物活性最高。  相似文献   
36.
P C Hu 《中华结核和呼吸杂志》1992,15(3):163-4, 191-2
In our study, we observed that (1) High RCIA were discovered in these two groups. (2) In the group of pulmonary tuberculosis, the C3b receptor activities remained no change after antituberculous therapy, but the amounts of immune complexes bearing on RBC decreased. In the patients with the high RCIA, CIC was discharged rapidly and the lesions of tissue produced by CIC were prevented. In the patients with silicotuberculosis, both silica and tuberculous bacilli may act as immune adjuvant and enhance the hypersensitivity. So the C3b receptor activities were higher in silicotuberculosis patients.  相似文献   
37.
38.
39.
40.
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