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   627144篇
  免费   28295篇
  国内免费   494篇
耳鼻咽喉   7456篇
儿科学   20271篇
妇产科学   14021篇
基础医学   102977篇
口腔科学   12883篇
临床医学   54705篇
内科学   115505篇
皮肤病学   12333篇
神经病学   43839篇
特种医学   24308篇
外国民族医学   53篇
外科学   95477篇
综合类   8504篇
现状与发展   2篇
一般理论   107篇
预防医学   47613篇
眼科学   12934篇
药学   45969篇
  1篇
中国医学   1130篇
肿瘤学   35845篇
  2021年   3893篇
  2018年   16784篇
  2017年   13235篇
  2016年   15965篇
  2015年   5731篇
  2014年   7402篇
  2013年   10760篇
  2012年   18662篇
  2011年   27197篇
  2010年   17722篇
  2009年   14774篇
  2008年   26115篇
  2007年   30329篇
  2006年   17170篇
  2005年   18138篇
  2004年   18426篇
  2003年   19245篇
  2002年   17494篇
  2001年   22743篇
  2000年   23513篇
  1999年   19130篇
  1998年   5436篇
  1997年   4633篇
  1996年   4559篇
  1995年   4290篇
  1992年   14549篇
  1991年   15965篇
  1990年   16091篇
  1989年   15751篇
  1988年   14420篇
  1987年   14332篇
  1986年   13280篇
  1985年   12798篇
  1984年   9469篇
  1983年   8068篇
  1982年   4272篇
  1979年   9041篇
  1978年   6452篇
  1977年   5168篇
  1976年   5573篇
  1975年   6614篇
  1974年   7449篇
  1973年   7167篇
  1972年   6597篇
  1971年   6309篇
  1970年   5913篇
  1969年   5504篇
  1968年   5183篇
  1967年   4621篇
  1966年   3963篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
A retrospective analysis of treatment for endometrial carcinoma is reported here. From 1987 to 1989, 138 patients were referred to the oncology department following total abdominal hysterectomy and bilateral salpingo-oophorectomy for endometrial cancer. Forty-seven patients were not prescribed postoperative radiotherapy; 31 had Stage I well differentiated adenocarcinoma with minimal myometrial invasion, while the remaining 16 patients were considered unfit for postoperative radiotherapy. There were no instances of local relapse amongst the 31 patients with minimal myometrial invasion.The remaining 91 patients all received external beam irradiation to the pelvis and, according to the preference of the individual therapist, 51 were prescribed additional intracavitary vault caesium-137. Patients receiving postoperative radiotherapy were analysed according to whether or not they received additional intracavitary vault caesium. The two groups were also analysed for incidence of vaginal vault recurrence and treatment related morbidity.In the group receiving additional intracavitary treatment more patients had Stage II or III disease (P<0.05), and had greater depth of myometrial invasion (P<0.05). Vaginal vault recurrence was not observed in patients receiving intracavitary therapy in addition to external beam therapy. Four patients (10%) receiving external beam therapy alone developed vaginal vault recurrence.The incidence of Kottmeier-Perez grade 2 or 3 bowel toxicity following treatment was significantly higher in those patients receiving combined treatment (18% vs. 2.5%; P<0.03). There was also a higher incidence of vaginal stenosis in the group receiving both external beam and intracavitary therapy (21% vs. 3%; P<0.05). There was only one instance of grade 2 bladder toxicity in the external beam and intracavitary treatment group and none in the external beam therapy alone group.In conclusion, postoperative radiotherapy for Stages I-III endometrial carcinoma was carried out in a non-randomized manner by two regimens; either external beam therapy alone or external beam therapy with additional intracavitary vaginal caesium. The combined therapy gave significantly better local control but resulted in significantly more late bowel and vaginal morbidity.  相似文献   
992.
Translated from Khimiko-farmatsevticheskii Zhurnal, Vol. 26, No. 5, pp. 43–45, May, 1992.  相似文献   
993.
V Labed  A Rannou  G Tymen 《Health physics》1992,63(2):172-178
Membranes that exclude water but are permeable to radon can extend the range of environments where many radon detection systems could operate. We have studied the permeation of 222Rn through polypropylene membranes separating air and water phases. The permeation coefficient and the activation energy were calculated for various conditions. Potential applications, such as in situ detection of radon in water, are discussed.  相似文献   
994.
A new technique of scanning electron microscopy for visualization of hidden cellular surfaces in organs and tissue has been developed. It employs the sample incubation in 30% potassium hydroxide and 96% alcohol mixed in equal amounts and dissociation until single cells appear in the solution, this being checked under phase-contrast microscope. The method is beneficial in non-standard cases of three-dimensional organization of organs and tissues.  相似文献   
995.
For certain genetic conditions DNA testing identifies carriers and determines the risk status of foetuses, thus helping parents to make more informed prenatal decisions. Data, collected from three genetic centres in England and Wales from August 1986 to July 1990, are used to describe trends in demand for DNA testing, the impact of DNA tests on carrier risk assessment, and the use of DNA tests in relation to pregnancy outcome. Altogether the data include 23,388 subjects and 681 pregnancies in 8738 families divided into five cohorts by year of entry and referral. The most frequent gene disorders referred to the genetic centres are currently being tested or will soon be tested. For these disorders the initial high level of activity has declined and may have reached steady state. Demand for DNA services is high for cystic fibrosis and Duchenne muscular dystrophy, intermediate for Huntington's disease, and low for adult polycystic kidney disease, phenylketonuria and tuberous sclerosis. Based on these findings we suggest that demand for DNA tests will be high in serious, untreatable and slow progressing conditions with early onset; intermediate for conditions affecting intellect and neurological integrity with later onset; and low for treatable, late-onset conditions, or those for which there is evidence of heterogeneity, and variable penetrance. It would be helpful to assess the extent to which this view of demand is confirmed when the new disorders being DNA tested are considered and for the pattern of activity of DNA testing for some types of cancer. Since no DNA centre could offer a fully comprehensive testing service, it is recommended that a structure is created to audit overall activity, assist in policy formulation, and influence supraregional service organisation, in order that the spread of DNA services be planned as effectively as possible. This structure would facilitate monitoring of the evolution of contract specifications agreed by commissioners and providers on a regional basis.  相似文献   
996.
Scientific-Research Institute for Medical Instrument Engineering, Moscow. Translated from Meditsinskaya Tekhnika, No. 6, p. 8, November–December, 1992.  相似文献   
997.
Neuropeptide signals and specific neuropeptide receptors have been described in the thymus supporting the concept of a close dialogue between the neuroendocrine and the immune systems at the level of early T-cell differentiation. In this paper, we review recent data about neurohypophysial (NHP)-related peptides detected in the thymus from different species. We suggest that we are dealing in fact with other member(s) of the NHP hormone family, which seems to exert its activity locally through a novel model of cell-to-cell signaling, that of cryptocrine communication. This model involves exchange of signals between thymic epithelial cells and developing thymocytes. The NHP-related peptides have been shown to trigger thymocyte proliferation and could induce immune tolerance of this highly conserved neuroendocrine family.  相似文献   
998.
Scientific-Research Center of Biomedical Radioelectronics, Moscow. Translated from Meditsinskaya Tekhnika, No. 6, pp. 36–37, November–December, 1992.  相似文献   
999.
Scientific Research Institute for Radiomeasuring Equipment, Kiev. Translated from Meditsinskaya Tekhnika, No. 2, pp. 21–24, March–April, 1992.  相似文献   
1000.
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