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   18773篇
  免费   867篇
  国内免费   84篇
耳鼻咽喉   121篇
儿科学   261篇
妇产科学   156篇
基础医学   2128篇
口腔科学   495篇
临床医学   1402篇
内科学   4749篇
皮肤病学   379篇
神经病学   1292篇
特种医学   608篇
外科学   3670篇
综合类   54篇
预防医学   428篇
眼科学   326篇
药学   1209篇
  1篇
中国医学   22篇
肿瘤学   2423篇
  2023年   136篇
  2022年   242篇
  2021年   393篇
  2020年   220篇
  2019年   296篇
  2018年   327篇
  2017年   317篇
  2016年   360篇
  2015年   361篇
  2014年   452篇
  2013年   566篇
  2012年   858篇
  2011年   908篇
  2010年   529篇
  2009年   435篇
  2008年   771篇
  2007年   822篇
  2006年   847篇
  2005年   860篇
  2004年   826篇
  2003年   808篇
  2002年   822篇
  2001年   641篇
  2000年   668篇
  1999年   589篇
  1998年   261篇
  1997年   184篇
  1996年   154篇
  1995年   145篇
  1994年   138篇
  1993年   139篇
  1992年   527篇
  1991年   491篇
  1990年   451篇
  1989年   436篇
  1988年   344篇
  1987年   319篇
  1986年   302篇
  1985年   258篇
  1984年   170篇
  1983年   158篇
  1979年   137篇
  1978年   94篇
  1977年   81篇
  1975年   63篇
  1974年   85篇
  1973年   74篇
  1972年   79篇
  1971年   76篇
  1969年   64篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
Changes of amplitude and implicit time of human cone electroretinogram (ERG) were studied during dark adaptation and succeeding light adaptation. Dark-adapted cone ERG was isolated by subtracting scotopic blue response from matched scotopic red response. The former represented the rod-mediated b-wave, while the latter consisted of both rod-mediated b-wave and cone-mediated b-wave or x-wave. The b-wave amplitude of dark-adapted cone ERG remained unchanged during dark adaptation, while the implicit time increased systematically, reaching a plateau. Light-adapted cone ERG was obtained by red stimulus lights under a bright background light. The amplitude of light-adapted cone ERG was markedly suppressed through dark adaptation but it recovered gradually during light adaptation, reaching the base line level. The implicit time was unchanged during light adaptation.  相似文献   
82.
83.
84.
A case of renal schwannoma is presented. A 51-year-old female was admitted to our hospital because of a left renal mass on April, 16, 1987. A drip infusion pyelogram showed encasement of the lower and medial calyx. An abdominal CT-scan showed a 2.5 cm mass with irregular density. Selective left renal arteriography showed the hypovascular tumor of the left kidney. Transperitoneal radical nephrectomy was performed on May, 1, 1987. Histological diagnosis was renal schwannoma arising from renal pelvis. The patient was well without recurrence 20 months after operation. Our present case is the 12th case of renal schwannoma reported in the English and Japanese literature.  相似文献   
85.
86.
This study was designed to investigate the effect of morphine on formalin-induced nociceptive responses in streptozotocin (STZ) induced-diabetic mice, noninsulin-dependent genetically diabetic db/db mice and their respective controls (ddY and +/+). In nondiabetic (ddY and +/+) mice, morphine (1–10 mg/kg, PO) dose dependently attenuated the biphasic nociceptive responses induced by SC injection of formalin to the hindpaw, demonstrating equipotency on both the first and second phases. Para-chlorophenylalanine (800 mg/kg × 2, PO) and pindolol (1 mg/kg, IP) reduced the effect of morphine on the first phase, sulpiride (10 mg/kg, IP) abolished the effect on both phases, while ketanserin (1 mg/kg, IP) had no effect. In STZ (200 mg/kg, IP)-diabetic mice, morphine weakly attenuated the nociception in comparison to control ddY mice, whereas it had comparable effects in both the first and second phases of control +/+ mice and db/db mice. The serotonergic agonist, meta-chlorophenylpiperazine (0.32–3.2 mg/kg, PO), dose dependently attenuated the biphasic nociceptive responses to formalin in both phases of diabetic mice; however, FR64822, a dopaminergic compound (0.1–10 mg/kg, PO), had little effect. We speculate that activation of both dopaminergic (DA)- and serotonergic-mediated mechanisms are potentially responsible for the effect of morphine on the first phase, while the DA-mediated effect is involved in the second phase. The DA-mediated mechanism, but not the serotonin-mediated one, appears to be altered in both STZ-diabetic and db/db mice. These results suggest that the attenuated effects of morphine might be due to a dopaminergic dysfunction in STZ mice, and that there might be other mechanisms compensating for this attenuation of dopaminergic function in db/db mice.  相似文献   
87.
88.
With regard to "acute kindling" that signifies progressive changes in various epileptiform discharges produced with repeated electrical stimulations in a brief time span in acute experiments, the interstimulation interval effect was examined. Kindling developments produced respectively with 3 and 30-minute interval stimulations to the visual cortex of rabbits were compared with each other. Eventually, in kindling with a longer interstimulation interval, after-discharges induced in every trial of stimulation were often lengthened in duration more prominently than those with the shorter interstimulation interval and, furthermore, occasional slight relapses in the afterdischarge duration occurred more infrequently in the former than in the latter. These results suggest that the interstimulation interval plays an important role in the development of acute kindling, presumably in relation to postictal inhibition. In addition, spontaneous interictal or ictal epileptiform discharges occasionally arising during the 3-minute interstimulation intervals were reported. These spontaneous discharges may suggest a high epileptogenicity in acute kindling.  相似文献   
89.
CA 125 is an antigen associated with non-mucinous epithelial ovarian cancer, which is defined by OC 125 antibody developed by immunizing ovarian cancer cells. We have produced two monoclonal antibodies, 130-22 and 145-9, by using the human lung adenocarcinoma cell line PC-9. Both 130-22 and 145-9 antibodies recognized CA 125 antigen. However, the binding sites seemed to be separate from those of OC 125. Testing by 9 immunoradiometric assays (IRMA), using different combinations of the 3 monoclonal antibodies 130-22, 145-9 and OC 125 demonstrated that the best standard curve for detecting CA 125 could be obtained by a "simultaneous sandwich" assay based on a mixture of 125I-labeled OC 125 and 130-22 or 145-9 coated beads. One-step IRMA, using 130-22 as a tracer and 145-9 as an immunoadsorbent, also showed good reproducibility and sensitivity for measuring CA 125. Antigens were detectable in the culture supernatants of PC-9 cells and 5 of 6 ovarian cancer and endometrial adenocarcinoma cells. These results indicate that one-step IRMA using 130-22 and 145-9 is useful for detecting CA 125 antigen.  相似文献   
90.
Among the routes of gaseous I transfer to rice grains, direct deposition to the hull of rice plants and the subsequent transfer to brown rice and polished rice should be more critical than leaf absorption-translocation. A grain number normalized deposition velocity (Vs) is recommended as a key parameter to assess the amount of gaseous I deposited on the rough rice. This parameter is given as "iodine content per unit number of grain per unit time" divided by "iodine concentration per unit volume of the air." After the heading period the surface area of rough rice is almost constant but weight increases with time. Therefore, mass normalized deposition velocity (VD) varies with time. By introducing Vs instead of VD, the variations could be converged into narrow ranges. The contribution of gaseous I from the atmosphere to rough rice, brown rice and polished rice were estimated using Vs values obtained experimentally and gaseous I concentration in the air.  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