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   43223篇
  免费   2073篇
  国内免费   228篇
耳鼻咽喉   476篇
儿科学   726篇
妇产科学   639篇
基础医学   5599篇
口腔科学   1365篇
临床医学   3210篇
内科学   10332篇
皮肤病学   1015篇
神经病学   3262篇
特种医学   1943篇
外科学   7159篇
综合类   264篇
一般理论   2篇
预防医学   1390篇
眼科学   669篇
药学   2903篇
中国医学   91篇
肿瘤学   4479篇
  2023年   228篇
  2022年   501篇
  2021年   896篇
  2020年   433篇
  2019年   638篇
  2018年   841篇
  2017年   648篇
  2016年   746篇
  2015年   841篇
  2014年   1123篇
  2013年   1263篇
  2012年   1966篇
  2011年   2177篇
  2010年   1213篇
  2009年   1088篇
  2008年   1887篇
  2007年   2020篇
  2006年   2046篇
  2005年   2139篇
  2004年   2044篇
  2003年   1955篇
  2002年   1999篇
  2001年   1328篇
  2000年   1470篇
  1999年   1324篇
  1998年   579篇
  1997年   418篇
  1996年   446篇
  1995年   394篇
  1994年   349篇
  1993年   324篇
  1992年   871篇
  1991年   806篇
  1990年   727篇
  1989年   736篇
  1988年   704篇
  1987年   685篇
  1986年   694篇
  1985年   616篇
  1984年   447篇
  1983年   362篇
  1979年   347篇
  1978年   238篇
  1977年   204篇
  1975年   206篇
  1974年   236篇
  1973年   215篇
  1971年   212篇
  1970年   204篇
  1969年   229篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
We report a case of biliary cystadenocarcinoma which recurred 41 months postoperatively. A 60-year-old woman was admitted for further examination of multiple metastatic tumors and a large amount of ascites. Systemic administration of 5FU and CDDP caused her CEA level to decrease gradually and abdominal computed tomography revealed considerable reduction of the metastatic tumors and ascites. Since her general condition had improved, chemotherapy was continued in the outpatient clinic.  相似文献   
4.
5.
The involvement of oxidative stress in polymorphonuclear leukocytes (PMN) in the pathogenesis of hypertension remains to be elucidated. We analyzed the generation of reactive oxygen species (ROS) by the circulating and peritoneally infiltrating PMN from spontaneously hypertensive rats (SHR) and Wistar Kyoto rats (WKY). Flow cytometric analysis revealed that ROS generation by PMN from SHR was higher than that from WKY before (at 6 weeks of age) and after (at 16 weeks of age) the onset of hypertension. In vivo, ROS generation by PMN from SHR, but not that by PMN from WKY, was significantly suppressed by 10-week treatment with 50 mg/kg/day carvedilol, and this treatment did not affect blood pressure. Western blotting analysis revealed that protein kinase C alpha (PKCalpha), but not PKCbetaI or betaII, was activated more strongly in PMN from SHR than in PMN from WKY. Furthermore, expression of p47phox of nicotinamide adenine dinucleotide phosphate oxidase, but not of p67phox, in PMN from SHR was higher than that in PMN from WKY. These results suggest that ROS generation by PMN is principally enhanced in SHR through activation of PKCalpha and p47phox.  相似文献   
6.
To form the human body and maintain the integrity of its complex tissues, individual cells need to hold tightly to each other. The desmosome is the major type of intercellular adhesive junction, and has desmoglein (Dsg), a cadherin type cell-cell adhesion molecule, as a transmembrane component. Dsg is now known to be targeted in autoimmune diseases, infectious diseases, as well as inherited diseases. Patients with pemphigus, an autoimmune blistering disease of the skin and mucous membrane, have IgG autoantibodies directed against Dsg1 and Dsg3. A subset of patients with pemphigus have Dsg1/Dsg4 crossreacting IgG autoantibodies. Exfoliative toxins produced by Staphylococcal aureus, which causes Staphylococcal Scalded Skin Syndrome (SSSS) and bullous impetigo, specifically digest Dsg1. A subset of patients with SSSS develop a low titer of anti-Dsg1 IgG autoantibodies. A mutation in DSG1 gene causes striate palmoplantar keratoderma and a mutation in DSG4 gene causes inherited hypotrichosis. It is not clear why so many diseases are clustered in desmogleins, but there must be a reason for this. Studies on desmogleins will provide an important framework to understand the mysteries between autoimmunity and infection.  相似文献   
7.
M Sato  H Kiyama  M Tohyama 《Neuroscience》1992,48(1):137-149
In situ hybridization histochemistry revealed three different ontogenetic patterns of localized expression of the high-affinity type of neurotensin receptor mRNA in the developing rat brain: one comprises sites which showed transient expression of neurotensin receptor mRNA during the first postnatal week, the expression greatly decreasing thereafter (type I); another comprises sites at which there is a gradual increase in neurotensin receptor mRNA after birth, as there is in cell number and intensity, with advancing age, followed by a plateau (type II); the third comprises sites at which there is much expression of neurotensin receptor mRNA already at birth, and a slight decrease thereafter (type III). The cerebral cortex, except retrosplenial and entorhinal cortices, and the anterior dorsal thalamic nucleus exhibit the type I pattern, while the horizontal and vertical limbs of the diagonal band of Broca, magnocellular preoptic nucleus, substantia innominata, ventral part of the suprachiasmatic nucleus, medial habenular nucleus, ventral tegmental area and substantia nigra pars compacta exhibit the type II pattern. The tenia tecta, retrosplenial and entorhinal cortices exhibit the type III pattern. One of the most striking findings in this study was that the entire neocortex and most of the limbic cortex exhibit the type I pattern, i.e. neurotensin receptor mRNA is expressed transiently long before a neuronal network is established there. This suggests that neurotensin plays an important role in cortical development, other than its reported transmitter-like role in the adult.  相似文献   
8.
Acupuncture analgesia (AA) caused by low frequency stimulation of the acupuncture point (AP) was abolished by hypophysectomy and adrenalectomy. Termination of the AA producing pathway from the AP to the pituitary gland was in the medial hypothalamic arcuate nucleus (M-HARN). The origin of the descending pain inhibitory system associated with AA was in the posterior HARN (P-HARN). AA in the hypophysectomized rats, and enhanced neuronal activity in the P-HARN that were abolished during acupuncture stimulation, were both restored by intraperitoneal microinjection of 0.5 mg/kg morphine or 0.1 micrograms beta-endorphin into the P-HARN during acupuncture stimulation. Of the analgesia produced by dopamine or beta-endorphin injected into the P-HARN, that caused by beta-endorphin disappeared after denervation of the M-HARN. The P-HARN neurons that responded to acupuncture stimulation also responded to iontophoretic dopamine, but not to iontophoretic morphine nor ultramicroinjected beta-endorphin. The transmission between the M-HARN and P-HARN may be dopaminergic, and beta-endorphin might presynaptically modulate this transmission. Reduction of sodium ions may have been the reason for abolition of AA after adrenalectomy.  相似文献   
9.
10.
A 50-year-old woman with bilateral inflammatory breast cancer (T4, N1b, M1, Stage IV) underwent right extended radical mastectomy and left modified radical mastectomy following pre-operative administration of carcinostatics (ADM, 5-FU) and irradiation. However, tumor recurrence was observed at the skin and right pleural cavity after the operation. Adriamycin-containing combination chemotherapy and radiation therapy were performed, but no significant response was obtained. CDDP was then administered intravenously at a daily dose of 62.5 mg/m2 at intervals of 60 days. The pleural effusion disappeared and the extent of skin metastasis was reduced, resulting in partial response which lasted for 90 days. The serum CEA level decreased from 13.1 ng/ml to 2.3 ng/ml. As the side effects of this therapy, slight nausea, vomiting and general fatigue were observed. This result suggested that CDDP is an effective drug for inflammatory breast cancer.  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