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   2360篇
  免费   99篇
  国内免费   21篇
耳鼻咽喉   8篇
儿科学   40篇
妇产科学   15篇
基础医学   186篇
口腔科学   41篇
临床医学   195篇
内科学   324篇
皮肤病学   6篇
神经病学   134篇
特种医学   1005篇
外科学   183篇
综合类   28篇
一般理论   2篇
预防医学   111篇
眼科学   22篇
药学   80篇
中国医学   3篇
肿瘤学   97篇
  2022年   5篇
  2019年   22篇
  2018年   22篇
  2017年   13篇
  2016年   30篇
  2015年   35篇
  2014年   52篇
  2013年   97篇
  2012年   105篇
  2011年   104篇
  2010年   107篇
  2009年   84篇
  2008年   110篇
  2007年   163篇
  2006年   123篇
  2005年   101篇
  2004年   106篇
  2003年   68篇
  2002年   104篇
  2001年   82篇
  2000年   93篇
  1999年   102篇
  1998年   73篇
  1997年   59篇
  1996年   56篇
  1995年   36篇
  1994年   41篇
  1993年   26篇
  1992年   21篇
  1991年   17篇
  1990年   23篇
  1989年   42篇
  1988年   44篇
  1987年   36篇
  1986年   50篇
  1985年   35篇
  1984年   26篇
  1983年   21篇
  1982年   24篇
  1981年   12篇
  1980年   8篇
  1979年   11篇
  1978年   9篇
  1977年   6篇
  1976年   5篇
  1975年   8篇
  1973年   6篇
  1972年   5篇
  1968年   6篇
  1966年   5篇
排序方式: 共有2480条查询结果,搜索用时 15 毫秒
1.
Ohne ZusammenfassungDie vorliegende Arbeit war als Vortrag für die abgesagte Tagung der Deutschen ophthalmologischen Gesellschaft angemeldet.Die Untersuchungen wurden mit Hilfe des Westdeutschen Tuberkulose-Forschungsinstitudes durchgeführt.  相似文献   
2.
3.
All types of four brands of tampons were tested in triplicate by a tampon sac method for their effect on production of toxic shock syndrome toxin 1 (TSST-1). In this method the available air is limited to that which is in the tampon sac. Tampons were weighed and inserted into dialysis sacs inoculated with a TSST-1-producing Staphylococcus aureus strain; the sacs were submerged into brain heart infusion agar, which was allowed to harden around the sacs, and were incubated for 18 h at 37 degrees C. The tampons were removed, weighed, and extracted; the CFU of staphylococci and the amount of toxin present in the extracts were determined. Glass wool was used in place of the tampons as one control, and inoculated empty sacs were used as a second control. The total CFU were consistently greater than 2 X 10(11) for the tampons and glass wool and less than or equal to 10(11) for the empty sac control. Total toxin production for all tampons tested and the glass wool was 2 to 10 times higher than the toxin produced with the empty sac control. These results indicate that tampons provide increased surface area for the staphylococci to grow and adequate oxygen for toxin production. No significant inhibition of growth of the staphylococci or TSST-1 production by any of the tampons tested was noted.  相似文献   
4.
5.
Various diseases of the central nervous system are characterized by induction of inflammatory events, which involve formation of prostaglandins. Production of prostaglandins is regulated by activity of phospholipases A(2) and cyclooxygenases. These enzymes release the prostaglandin precursor, the n-6 polyunsaturated fatty acid, arachidonic acid and oxidize it into prostaglandin H(2). Docosahexaenoic acid, which belongs to the n-3 class of polyunsaturated fatty acids, was shown to reduce production of prostaglandins after in vivo and in vitro administration. Nevertheless, the fact that in brain tissue cellular phospholipids naturally have a uniquely high content of docosahexaenoic acid was ignored so far in studies of prostaglandin formation in brain tissue. We consider the following possibilities: docosahexaenoic acid might attenuate production of prostaglandins by direct inhibition of cyclooxygenases. Such inhibition was found with the isolated enzyme. Another possibility, which has been already shown is reduction of expression of inducible cyclooxygenase-2. Additionally, we propose that docosahexaenoic acid could influence intracellular Ca(2+) signaling, which results in changes of activity of Ca(2+)-dependent phospholipase A(2), hence reducing the amount of arachidonic acid available for prostaglandin production. Astrocytes, the main type of glial cells in the brain control the release of arachidonic acid, docosahexaenoic acid and the formation of prostaglandins. Our recently obtained data revealed that the release of arachidonic and docosahexaenoic acids in astrocytes is controlled by different isoforms of phospholipase A(2), i.e. Ca(2+)-dependent phospholipase A(2) and Ca(2+)-independent phospholipase A(2), respectively. Moreover, the release of arachidonic and docosahexaenoic acids is differently regulated through Ca(2+)- and cAMP-dependent signal transduction pathways. Based on analysis of the current literature and our own data we put forward the hypothesis that Ca(2+)-independent phospholipase A(2) and docosahexaenoic acid are promising targets for treatment of inflammatory related disorders in brain. We suggest that Ca(2+)-independent phospholipase A(2) and docosahexaenoic acid might be crucially involved in brain-specific regulation of prostaglandins.  相似文献   
6.
In contrast to conventional film angiography, the perfusion pattern of hepatic arterial chemotherapy was consistently visualized by DSA in 40 patients with implanted Infusaid pump or Port-A devices. Incomplete perfusion of a liver region by the cytotoxic agent was recognized by DSA as accurately as by nuclide scintigraphy. Furthermore, DSA appeared to be more sensitive in determining aberrantly perfused extrahepatic regions; this was especially true when there was a nonligated right hepatic artery. Specific details of vascular lesions and associated complicating events also could be satisfactorily analyzed by DSA only.  相似文献   
7.
The erect penis--injury prone organ   总被引:3,自引:0,他引:3  
Erection converts the safe, flaccid penis into a vulnerable organ. During erection, the usually thick tunica albuginea becomes very thin and easily fracturable. Penile fracture is an under-reported urologic injury, with only approximately 100 cases reported in the world literature. We report on three cases, one with rupture of one corpus spongiosum and two with rupture of both corpora cavernosa associated with almost complete transection of the urethra. All three cases were treated surgically, with good outcome and no postoperative complications. The authors postulate that some cases of deviation of the penis are actually the result of some minor degree of penile fracture.  相似文献   
8.
Psychiatry is part of medicine, and developing competence to deal with the mental life of patients is an essential part of general medical as well as psychiatric subspecialty education. As psychiatry's neurobiological data base, therapeutic armamentarium, scope of interest, and philosophical views expand and competitive pressures for time in residency training are intensified, teaching in the mental sciences and opportunities for residents to develop solid psychodynamic diagnostic and therapeutic skills are rapidly disappearing. However, brain science does not yet, and probably never will, fully explain the mind. The author urges psychiatric educators not to give up the mind or, worse yet, lose it by default.  相似文献   
9.
Brain cells from embryonic chick (stage 28-29) were cultivated for 16 days under serum-free conditions. Nerve cells were found to mature during the first 7 days in culture, as indicated by the presence and developmental pattern of the relative amount of dendritic-specific microtubule-associated protein type 2 (MAP2). Maximal amounts of MAP2 antigen were found to be directly correlated with the number of cells plated out. Astroglia cell proliferation and differentiation, as measured by the amounts of glial fibrillary acidic protein (GFAP), were found to stabilize after a certain astrocyte cell density was reached. Variation in culture plate coating procedure, oxygen tension and addition of serum or of the cytostatic drug Ara-C were found to differently affect viability and maturation processes of astroglia and of nerve cells. Moreover, optimal culture conditions for long-term brain cell cultures are described.  相似文献   
10.
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