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   531749篇
  免费   27754篇
  国内免费   496篇
耳鼻咽喉   6686篇
儿科学   16954篇
妇产科学   12575篇
基础医学   92885篇
口腔科学   12438篇
临床医学   48692篇
内科学   95687篇
皮肤病学   11888篇
神经病学   34125篇
特种医学   19786篇
外国民族医学   53篇
外科学   78285篇
综合类   7672篇
现状与发展   3篇
一般理论   110篇
预防医学   38842篇
眼科学   11970篇
药学   41505篇
  1篇
中国医学   1126篇
肿瘤学   28716篇
  2019年   3924篇
  2018年   5762篇
  2017年   4147篇
  2016年   4900篇
  2015年   5395篇
  2014年   7161篇
  2013年   10547篇
  2012年   15649篇
  2011年   17468篇
  2010年   9987篇
  2009年   8863篇
  2008年   15800篇
  2007年   17562篇
  2006年   17040篇
  2005年   16350篇
  2004年   15961篇
  2003年   15334篇
  2002年   14841篇
  2001年   22480篇
  2000年   23052篇
  1999年   18977篇
  1998年   5249篇
  1997年   4399篇
  1996年   4416篇
  1995年   4147篇
  1992年   14451篇
  1991年   15863篇
  1990年   15992篇
  1989年   15653篇
  1988年   14334篇
  1987年   14223篇
  1986年   13187篇
  1985年   12700篇
  1984年   9419篇
  1983年   8023篇
  1982年   4189篇
  1979年   8951篇
  1978年   6390篇
  1977年   5152篇
  1976年   5506篇
  1975年   6618篇
  1974年   7427篇
  1973年   7164篇
  1972年   6601篇
  1971年   6315篇
  1970年   5893篇
  1969年   5472篇
  1968年   5163篇
  1967年   4621篇
  1966年   3966篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
A total of 102 patients were examined, 32 of these with true eczema, 38 with exudative mycosis of the soles, and 32 with eczema etiologically related to a fungal infection. Analysis of the immune and biochemical reactions in the examinees has shown a marked reduction of adenyl nucleotides in the leukocytic suspension and neutrophils of patients with a mycotic infection as against those with true eczema. The lowest creatine phosphate levels were detected in the leukocytic suspension and neutrophils of the patients suffering from eczema etiologically related to mycosis and exudative mycosis of the soles. These results give grounds to search for effective corrective therapy.  相似文献   
82.
This paper discusses the application of intravenous Kalipsol anesthesia in combination with Seduxen (Relanium) in 22 patients who underwent antro-mastoidectomy (expanded) and fronto-ethmoidectomy. No complications related to the method of anesthesia were identified. It is concluded that the use of Kalipsol anesthesia in urgent ENT operations provides better surgical intervention. This method ensures adequate analgesia during operation.  相似文献   
83.
This paper reports the changes in prolactin levels after 12 spontaneous and 52 induced pregnancies in 54 women with unambiguous hyperprolactinaemia (median plasma prolactin levels 67.5 ng/ml, range 40-400). Twenty-three of the patients showed radiological evidence of prolactinoma. The pregnancies were induced in 37 patients by bromocriptine, in nine by metergoline, in two by lisuride and in four by other treatments. Of the 64 pregnancies, 16 ended in spontaneous abortion, while 48 went to term. Follow-up was continued for at least 6 months after delivery or until the end of lactation. In a control group of 32 hyperprolactinaemic women (median prolactin 70 ng/ml, range 40-400) not wishing to become pregnant, prolactin changes were similarly registered over a mean period of 15 months without any treatment (range 6-38 months). After pregnancy, a significant downward trend of plasma prolactin was observed in the puerperal women with a 'normalization' rate of 17%. No changes were observed in the 32 controls who did not become pregnant.  相似文献   
84.
Endogenous opioids are present in neurons of the vagus and the intrinsic nervous system and they are colocalized with gastrin in antral G-cells. This raises the possibility that endogenous opioids modulate gastrin release. Stimulation of both cervical vagi (10V, 5Hz, 5ms) elicited an increase of arterial plasma gastrin levels at intragastric pH7 or pH2. The response at pH2 was 30% of that at luminal pH7. Atropine reduced vagally stimulated gastrin levels substantially. At luminal pH2 the small residual noncholinergic response was mediated neither by adrenergic mechanisms nor by endogenous opioids. At luminal pH 7 adrenergic blockade with phentolamine and propranolol reduced vagally stimulated gastrin by 60%. In the presence of atropine adrenergic blockade elicited only a small inhibitory effect suggesting that vagal activation of adrenergic mechanisms depends on atropine-sensitive cholinergic pathways. Blockade of opiate receptors by naloxone had no effect on vagal gastrin release, however, the noncholinergic gastrin response was reduced significantly by naloxone, suggesting that cholinergic mechanisms normally restrain activation of endogenous opioids during vagal stimulation. Naloxone had no effect on the noncholinergic, nonadrenergic stimulation of gastrin levels. These data suggest that endogenous opioids can contribute to vagal gastrin release provided the cholinergic restraint is blocked and adrenergic mechanisms stimulate endogenous opioids. In conclusion a major role of endogenous opioids in the regulation of vagal gastrin release can not be detected.  相似文献   
85.
The oncocytic Schneiderian papilloma (OSP) is a rare neoplasm of the nose and paranasal sinuses. The majority of the approximately twenty patients reported in the literature with this papilloma have been over the age of fifty at the time of diagnosis. The 33-year-old woman reported here is the youngest patient with this lesion to date. The OSP should be considered in the work-up of all unilateral nasal polypoid lesions. This lesion's propensity for recurrence and its documented association with synchronous malignant disease warrant surgical excision by en bloc resection of the lateral nasal wall, with corresponding careful microscopic evaluation of all excised tissue.  相似文献   
86.
In a double-blind study, mice were injected intraperitoneally with 0.2 ml 0.2% octoxynol-9 (O-9), 0.2 ml 0.2% nonoxynol-9 (N-9), or 0.2 ml saline (control) daily for 24 days. Another control group received no treatment. All mice were immunized twice with sheep red blood cells (SRBC) and bled by caudal incision. Mice receiving N-9 lost weight (P less than 0.02), had smaller livers (P less than 0.05), and showed enlarged spleens (P less than 0.05). The N-9-treated mice did not differ from either control group in the primary or secondary anti-SRBC responses, leukocyte (WBC) counts, or in the sizes of the kidneys, hearts, lungs, or thymuses. Mice receiving O-9 showed no significant differences from either control group in any of these tests. Serum immunoglobulin M (IgM) and immunoglobulin G (IgG) levels were similar in mice treated with O-9, N-9, or saline. All 3 groups had higher levels of both classes of immunoglobulins on day 16 than did untreated controls. This study shows that O-9, given to mice in doses 3 times that used by humans, is nontoxic, whereas the same dose of N-9 has minor deleterious effects.  相似文献   
87.
88.
89.
Using cortical cups in chloralose-urethanized rats, the in vivo release of cholecystokinin-like immunoreactivity (CCK-LI) from cerebral cortex was examined. Resting levels of cholecystokinin-like immunoreactivity ranged from 20 to 30 pg/20 min sample. The addition of potassium (40 mM) in excess, resulted in a highly significant elevation in the levels of CCK-LI in the cortical superfusate. Deletion of calcium and the substitution of cobalt (10 mM), resulted in a significant reduction in both resting release and the release otherwise evoked by the addition of potassium. Focal electrical stimulation of the cortex (20 Hz), resulted in a significant (1.9 +/- 0.2-fold, n = 8) increase in the levels of CCK-LI. The addition of glutamate (10(-6)-10(-4) M) of kainic acid (10(-8)-10(-6) M), also resulted in significant elevations in the levels of CCK-LI. The co-administration of a putative glutamate receptor antagonist, kynurenic acid (10(-4) M) resulted in a significant reduction in the levels of release otherwise evoked by the addition of glutamate, but not by electrical stimulation. The addition of GABA (10(-5)-10(-3) M) resulted in a dose-dependent decrease in the resting release of CCK-LI, and the release evoked by glutamate. Picrotoxin (10(-6)-10(-4) M), resulted in a highly significant increase in the levels of CCK-LI in the cortical effluent. These results are consistent with a tonic GABAergic inhibition of CCK-releasing neurons. The treatment of the animal with diazepam (30 mg/kg, i.p.) also resulted in a significant reduction in resting release and the release otherwise evoked by focal cortical stimulation.  相似文献   
90.
Inborn errors of the urea cycle are an important cause of hyperammonaemia throughout childhood, and are associated with high morbidity and mortality rates. If they are diagnosed early and treated appropriately, the outcome for affected children is significantly improved.  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