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   12001篇
  免费   685篇
  国内免费   59篇
耳鼻咽喉   120篇
儿科学   324篇
妇产科学   156篇
基础医学   1865篇
口腔科学   209篇
临床医学   904篇
内科学   2830篇
皮肤病学   293篇
神经病学   1021篇
特种医学   475篇
外科学   1286篇
综合类   76篇
预防医学   549篇
眼科学   263篇
药学   1051篇
中国医学   35篇
肿瘤学   1288篇
  2023年   97篇
  2022年   168篇
  2021年   264篇
  2020年   141篇
  2019年   222篇
  2018年   264篇
  2017年   205篇
  2016年   246篇
  2015年   215篇
  2014年   320篇
  2013年   428篇
  2012年   687篇
  2011年   713篇
  2010年   410篇
  2009年   399篇
  2008年   635篇
  2007年   737篇
  2006年   684篇
  2005年   728篇
  2004年   707篇
  2003年   663篇
  2002年   662篇
  2001年   256篇
  2000年   236篇
  1999年   256篇
  1998年   136篇
  1997年   141篇
  1996年   112篇
  1995年   107篇
  1994年   66篇
  1993年   95篇
  1992年   174篇
  1991年   151篇
  1990年   160篇
  1989年   141篇
  1988年   127篇
  1987年   122篇
  1986年   129篇
  1985年   82篇
  1984年   93篇
  1983年   69篇
  1982年   33篇
  1980年   28篇
  1979年   59篇
  1978年   29篇
  1975年   28篇
  1974年   29篇
  1972年   32篇
  1971年   33篇
  1970年   37篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
993.
Surgical nerve reconstruction for brachial plexus birth injuries and preoperative myelography and computed tomographic (CT) myelography require special anaesthetic considerations. Anaesthesia and medical records were retrospectively reviewed for the infants who underwent myelography, CT myelography (n=37) and microsurgical nerve reconstruction (n=34) at our institution from January 1993 to August 1996. Anaesthetic considerations include long duration of operation, perioperative respiratory complications and plaster application which makes reintubation difficult. Myelography for diagnosis requires a specific positioning of the patient with the head fixed in a midline and prone position.  相似文献   
994.
Despite cis-platin-based combination chemotherapy with initially high response rates in advanced ovarian cancer, the overall survival rate remains unsatisfactory. This prompted us to design a new systematic approach using a combination chemotherapy consisting of cis-platin, adriamycin and cyclophosphamide (PAC), namely cyclic-PAC chemotherapy: Three-step chemotherapies consisting of 3 courses of the PAC regimen in each step were administered for 18 months to patients with Stage Ic-IV, after cytoreductive surgery and chemotherapy. In the present study, the survival rate with the cyclic-PAC chemotherapy was compared to that with short course-PAC and FAM (5-Fu, Alkylating agent and Mitomycin C) chemotherapies. The cyclic-PAC, PAC and FAM groups included 24 cases, 31 cases and 30 cases, respectively. Treatment of Stage Ic-IV diseases by cyclic-PAC improved the outcome (66% 3-year survival rate) compared to PAC and FAM groups (PAC 35% and FAM 30% 3-year survival rates), while no difference was observed between PAC and FAM. The outcome for patients with Stage III. IV was also superior for the cyclic-PAC group compared to the PAC and FAM groups (cyclic-PAC 54%, PAC 18% and FAM 13% 3-year survival rates). Cyclic-PAC chemotherapy is capable of dramatically improving the long-term survival rate of ovarian cancer patients.  相似文献   
995.
996.
Using Ia antigen-containing lipid vesicles, we investigated by stopped-flow fluorometry the requirements for helper T cell recognition and activation. When azobenzenearsonate-L-tyrosine (ABA-L-Tyr)-specific, I-Ak-restricted helper T cell hybridomas 2-45-12 were mixed with ABA-L-Tyr and purified I-Ak molecules on lipid vesicles, an increase of intercellular calcium ion concentration ([Ca2+]i) in the T cells were detected within 1-2s. The average increases of [Ca2+]i were not much different when the lipid vesicles were composed of dimyristoylphosphatidylcholine or of egg phosphatidylcholine, but they were dependent on the density of I-Ak molecules on the liposomes. The increase of [Ca2+]i was inhibited in the presence of anti-I-Ak monoclonal antibody 10.2.16, but not by the addition of anti-L3T4 monoclonal antibody GK1.5. However, the addition of anti-L3T4 antibody during the first 3 h of cultivation completely inhibited the T cell activation [interleukin (IL-2) production]. In our experimental system, IL-2 production was observed either when L3T4-positive T cell hybridomas 2-45-12 were stimulated with ABA-L-Tyr and Ia molecules on the vesicles in the presence of phorbol 12-myristate 13-acetate, or when L3T4-negative T cell hybridomas 3H60.12 were incubated with ABA-L-Tyr and Ia molecules on the planar membranes.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
997.
Monoclonal antibody (moAB) OKB19 reacts with CD19 antigen, which is the broadest lineage-specific surface marker on B-lymphocytes. In frozen tissue sections, using an immunohistochemical technique, the OKB19-positive cells in the basal layer were sharply demarcated from the negative suprabasal layers. In normal hair follicles, the OKB19 reactivity was also confined to one layer of the dermal side of the outer root sheath. However, this reactivity gradually disappeared in the lower areas. The inner surface of the lumina in the eccrine duct was weakly stained with OKB19. The basal keratinocytes were also stained with OKB19 in the lesional epidermis of the various dermatoses examined in this study, when the basal keratinocytes remained unaffected. Even in the hyperproliferative state of psoriasis, the OKB19 reactivity was confined to the basal layer. Several kinds of tumor cells derived from the skin were not stained with OKB19. No labeling was seen even in the basaloid cells of basal cell carcinoma, which are morphologically similar to basal keratinocytes. B4 and Leu-12, other monoclonal antibodies reacting with CD19, did not recognize any keratinocytes in the normal human skin. MoAB OKB19, therefore, reacts with an antigen present on basal keratinocytes and provides a probe for the isolation of the basal keratinocyte subpopulation. Thus, this antibody should be useful in studies of not only B-lymphocyte differentiation, but also normal and aberrant differentiation of the epidermal keratinocytes.  相似文献   
998.
Wide attention has been given to hyperthermia as a new measure for cancer treatment. Clinical trials of hyperthermia, as they possess antitumour activity on some occasions. When cells were incubated with oleic we examine if fatty acids exert a synergistic effect on Ehrlich ascites tumour cells when combined with hyperthermia, as they possess antitumour activity on some occasions. When cells were incubated with oleic acid and linoleic acid (unsaturated fatty acids) at 37 degrees C, the DNA synthesis of cells was significantly inhibited. Palmitic and stearic acids, which are saturated fatty acids, did not suppress DNA synthesis. Hyperthermic treatment without the presence of fatty acids at 42 degrees C for 1 h decreased DNA synthesis to 62% of the control level of 37 degrees C. The combination of an unsaturated fatty acid and hyperthermia synergistically suppressed DNA synthesis. When the cells were incubated in serum-free medium containing 0.1% albumin, unsaturated fatty acids were more effective in inhibiting DNA synthesis. However, saturated fatty acids had little or no effect on DNA synthesis in control or hyperthermia-treated cells. These results indicate that unsaturated fatty acids are useful for enhancing the inhibitory effect of hyperthermia on DNA synthesis, which may increase the in vitro antitumour effects of hyperthermia.  相似文献   
999.
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