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   4518篇
  免费   450篇
  国内免费   7篇
耳鼻咽喉   125篇
儿科学   163篇
妇产科学   179篇
基础医学   614篇
口腔科学   52篇
临床医学   391篇
内科学   918篇
皮肤病学   51篇
神经病学   564篇
特种医学   221篇
外科学   634篇
综合类   217篇
一般理论   2篇
预防医学   290篇
眼科学   76篇
药学   169篇
中国医学   1篇
肿瘤学   308篇
  2021年   60篇
  2019年   42篇
  2018年   72篇
  2016年   37篇
  2015年   56篇
  2014年   74篇
  2013年   103篇
  2012年   131篇
  2011年   161篇
  2010年   94篇
  2009年   97篇
  2008年   161篇
  2007年   181篇
  2006年   167篇
  2005年   187篇
  2004年   168篇
  2003年   155篇
  2002年   151篇
  2001年   161篇
  2000年   171篇
  1999年   136篇
  1998年   94篇
  1997年   68篇
  1996年   75篇
  1995年   54篇
  1994年   60篇
  1993年   39篇
  1992年   129篇
  1991年   127篇
  1990年   125篇
  1989年   123篇
  1988年   112篇
  1987年   116篇
  1986年   125篇
  1985年   98篇
  1984年   95篇
  1983年   73篇
  1982年   46篇
  1981年   52篇
  1980年   38篇
  1979年   66篇
  1978年   48篇
  1977年   45篇
  1976年   40篇
  1975年   41篇
  1974年   57篇
  1973年   51篇
  1971年   46篇
  1970年   42篇
  1968年   41篇
排序方式: 共有4975条查询结果,搜索用时 444 毫秒
1.
L A Rodriguez  M Prados  P Silver  V A Levin 《Cancer》1989,64(12):2420-2423
Ninety-nine patients with primary recurrent malignant tumors of the central nervous system were treated with procarbazine as a single agent. Procarbazine was not given as a specified protocol, but for patients who were ineligible or refused other protocols. All patients had been treated previously with radiotherapy and 96 patients had also received previous chemotherapy. Twenty-five patients were treated at the first progression of their tumor, 47 were treated at the second progression, and 27 were treated at the third progression of their tumor. For the aggregate, the response plus stabilization rate was 27% for glioblastoma multiforme with median time to tumor progression of 30 weeks, and 28% for other anaplastic gliomas with a median time to tumor progression of 49 weeks. With respect to the percent of patients who responded or stabilized to treatment, these results are inferior to those reported previously for patients treated with procarbazine at recurrence. With respect to duration of response and stabilization, the data are comparable.  相似文献   
2.
The use of adjuvant radiation therapy in breast cancer patients treated with mastectomy and adjuvant chemotherapy has been controversial. In order to assess the necessity and effectiveness of adjuvant radiation therapy in this setting, we reviewed the results in 510 patients with T1-T3 tumors and pathologically positive nodes or tumors larger than 5 cm and negative nodes who were treated with adjuvant chemotherapy. Patients with four or more positive nodes or at least one positive apical node were randomized to receive either five or ten cycles of cyclophosphamide/Adriamycin (Adria Laboratories, Columbus, OH) (CA) and patients with one to three positive nodes or operable tumors larger than 5 cm and pathologically negative nodes were randomized to receive eight cycles of either cyclophosphamide, methotrexate, and 5-fluorouracil (5-FU) (CMF) or methotrexate and 5-FU (MF) chemotherapy. Two hundred six of these patients were subsequently rerandomized to receive either no further treatment or adjuvant radiotherapy. Thirty-five patients withdrew after randomization, including 34 who declined to receive radiotherapy. Radiation therapy consisted of 4,500 cGy in 5 weeks to the chest wall and appropriate draining lymph nodes. Median follow-up from chemotherapy randomization is 45 months for patients in the CA arm and 53 months for those in the CMF/MF arm. The crude rate of local failure (chest wall or draining lymph node areas) as first site of failure for patients randomized to receive chemotherapy only was 14%; for those randomized to receive both chemotherapy and radiotherapy it was 5% (P = .03). For patients in the CMF/MF arm, the rate of local failure as the first site of failure was nearly the same for patients randomized to chemotherapy only as for those randomized to adjuvant radiotherapy as well (5% v 2%). For patients in the CA arm, the crude rate of local failure was 20% for patients randomized to receive chemotherapy only, and 6% for those randomized to both types of adjuvant treatment (P = .03). Among the 43 patients treated with CA who actually received radiotherapy, there was only one local failure, compared with 12 local failures among the 59 patients (20%) who actually did not receive radiotherapy (P = .007). No significant difference was seen in disease-free survival or overall survival in either the CA or the CMF/MF arm between patients randomized to receive radiation therapy and those randomized to no further treatment.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   
3.
4.
5.
Polycythemia vera is a myeloproliferative disease, which, if untreated, leads to thrombohemorrhagic complications and eventually to progressive myelofibrosis, anemia, and splenomegaly. Two newly available drugs, interferon alfa and imatinib mesylate, may alter the course of this disease. Used as single agents, each produces lasting remissions in about 75% of patients with polycythemia vera. Of significance, change in JAK2 expression has been reported after treatment with both agents.  相似文献   
6.
Non-Hodgkin's lymphoma usually presents with lymphadenopathy at multiple sites but can also involve any part of the musculoskeletal system. Occasionally the presentation is with a soft tissue mass. The presentation of large, superficial lymphomatous masses is similar both clinically and radiologically to that of soft tissue sarcomas. The six cases of lymphoma presenting to the Exeter Sarcoma Service as suspected soft tissue sarcomas, over a two-year period (2002-2004), are presented. We describe the clinical and imaging characteristics of these tumours and their subsequent management. Our cases showed variability in presentation. Only one of the six cases presented with pain and one with tenderness. Four of the cases had no lymphadenopathy and the other two had lymphadenopathy restricted to one nodal basin. Overlying soft tissue swelling occurred in four cases and in distal limb swelling beyond the mass in one case. Radiologically, lymphomas are known to be likely to exhibit confluent lymphadenopathy that is rare in patients with soft tissue sarcoma. Confluent lymphadenopathy was demonstrated in only one case of this series of patients. It is thought that lymphomas infiltrate across anatomical fascial planes more readily than sarcomas and in four of our six cases this feature was present. Clinical history, examination and MRI are insufficient to differentiate between soft tissue sarcoma and lymphoma and the importance of obtaining a pathological diagnosis prior to surgery is clear. It is crucial to differentiate lymphoma from sarcoma in order to avoid unnecessary excisional procedures in lymphoma patients.  相似文献   
7.
The effect of an informational program in which the benefits and disadvantages of directed donations are discussed directly with the prospective recipient of the blood and/or that patient's family was examined during a 20-month period. Data collected for 27 regional Connecticut hospitals that accept directed donations were compared with similar data for Hartford Hospital, an 885-bed tertiary-care facility. The number of directed-donor units (68) collected by the American Red Cross Blood Services for Hartford Hospital during the study period was comparable to the number (average, 62.3) provided for smaller (301-450 beds) institutions in the state. The percentage that directed-donor units drawn for Hartford Hospital represented of the total number of homologous units provided (0.23%) was less than that for any of the categories of hospitals, by size, in the state. Supplying the patient and/or the patient's family, in a personalized manner, with information concerning the advantages and disadvantages of directed as well as of volunteer donor blood can result in a marked overall reduction in the number of directed donations and also serves to reassure those concerned about blood transfusion.  相似文献   
8.
9.
In response to professional and political pressures in 1967, an incident occurred at the Department of Health, Education, and Welfare that illustrates the delicacy and complexity of the legislative process. In an effort to bypass interest group influences, the undersecretary of the Department undertook a maneuver that backfired and frustrated an opportunity that might have resulted in the establishment of a Cabinet office of Health. In addition to demonstrating the sensitivity of the legislative process, and the dangers of overconfidence in dealing with the process, the events also offer moral guidance: too stubborn, idealistic convictions of good people, however well intentioned the actions, may serve to defeat the desired ends.  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