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   26315篇
  免费   1401篇
  国内免费   57篇
耳鼻咽喉   409篇
儿科学   1113篇
妇产科学   872篇
基础医学   4256篇
口腔科学   588篇
临床医学   2162篇
内科学   5225篇
皮肤病学   534篇
神经病学   2588篇
特种医学   1064篇
外国民族医学   14篇
外科学   3787篇
综合类   117篇
一般理论   3篇
预防医学   1383篇
眼科学   508篇
药学   1364篇
中国医学   19篇
肿瘤学   1767篇
  2022年   218篇
  2021年   369篇
  2020年   250篇
  2019年   340篇
  2018年   419篇
  2017年   355篇
  2016年   491篇
  2015年   472篇
  2014年   644篇
  2013年   824篇
  2012年   1188篇
  2011年   1262篇
  2010年   624篇
  2009年   679篇
  2008年   1152篇
  2007年   1239篇
  2006年   1157篇
  2005年   1192篇
  2004年   985篇
  2003年   982篇
  2002年   909篇
  2001年   902篇
  2000年   932篇
  1999年   789篇
  1998年   343篇
  1997年   266篇
  1996年   218篇
  1995年   202篇
  1994年   180篇
  1993年   178篇
  1992年   481篇
  1991年   507篇
  1990年   489篇
  1989年   405篇
  1988年   384篇
  1987年   402篇
  1986年   391篇
  1985年   388篇
  1984年   272篇
  1983年   211篇
  1982年   137篇
  1981年   143篇
  1979年   260篇
  1978年   183篇
  1977年   155篇
  1976年   153篇
  1975年   164篇
  1974年   192篇
  1973年   167篇
  1972年   154篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
OBJECTIVE: One of the main limitations of image-guided surgery is that navigation relies on the use of a CT scan obtained before surgery and is unable to be updated during the procedure. A software addition has been developed to allow reconstruction of CT-like images from a series of fluoroscopic scans and integrate these into an image-guided system (GE Healthcare Surgical Navigation, Lawrence, MA). We report our initial experience with a series of patients undergoing intraoperative fluoroscopic navigation in sinus surgery. STUDY DESIGN AND SETTINGS: After institutional review board clearance, we prospectively studied 14 consecutive patients undergoing image-guided sinus surgery with the use of intraoperative fluoroscopy. RESULTS: All patients had preoperative and postoperative fluoroscopic images reconstructed into CT-like images. By the conclusion of the study, images were adequate in quality and accurate navigation was achieved. CONCLUSION: Real-time image-guided sinus surgery using fluoroscopy is feasible. Future studies will need to focus on defining the procedures that could benefit, such as tumor resection, to enhance patient safety during these operations.  相似文献   
32.
Efficacy of interventions with caregivers: a reanalysis   总被引:2,自引:0,他引:2  
This paper presents a reanalysis of data from a previously reported study with family caregivers of dementia patients using the method of prediction analysis. Compared with subjects on a waiting list or enrolled in support groups, caregivers in individual and family counseling were more likely to have successful outcomes on all dependent measures (Brief Symptom Inventory, personal strain, and role strain).  相似文献   
33.
Compared to other forms of cancer, malignant mesenchymal tumors are rare: individual surgeons see few such patients and do not usually treat them personally. The radiologic and histologic problems of differential diagnosis, and the subtle distinction between benign and malignant make decision an onerous task for surgeons, orthopedists, pathologists, oncologists and radiotherapists. For this reason referral centers should enable oncologic working groups to confirm diagnoses, establish appropriate therapeutic schedules, and to help in follow-up patient care. Around 1970, a center was created at Balgrist University Orthopedic Clinic for the gathering, documentation and coordination of clinical and pathological data from patients with tumors and tumorous lesions of the skeleton and soft tissues. Subsequently, a circle of continuously collaborating specialists, including some from other institutions, formed about the register. The viability of the reference center is assured by unequivocal morphologic diagnosis; presence of the pathologist during the planning and procedure of the biopsy and other tumor-related interventions in the operating room; clinical investigations including the immediate availability of diagnostic procedures; charting all clinical data; and the clinic's follow-up of its own patients. Fully integrated in the Orthopedic Clinic and Polyclinic, the register is a major instrument in the treatment of patients at risk with tumor. Given the diversity of clinicopathological presentation, the register permits direct access to analogous situations in individual cases.  相似文献   
34.
35.
Abstract. A prospective randomized study was conducted to evaluate the impact of four different conversion protocols on graft outcome in long-term follow-up. Between January 1986 and May 1987, 128 patients with first cadaveric kidney allografts were randomized at the time of transplantation to four treatment groups of 32 patients each, to be assigned 10 weeks post-transplantation. During the first 10 weeks, all patients received triple therapy with low-dose azathioprine (Aza), cyclosporin (CyA), and methylprednisolone (MP). After 10 weeks, one group continued with triple therapy (group A) while the three other groups received different combinations of two drugs, namely, Aza and CyA (group B), Aza and MP (group C), or CyA and MP (group D). Withdrawal of MP (group B) or especially of CyA (group C) was associated with 4/29 (14%) and 10/28 (36%) acute rejection episodes, respectively, for 60 days after conversion. All rejections were mild and reversible. There were no rejections after Aza withdrawal or in the group that continued on triple therapy during the corresponding time period. The most common reason for dropping out after withdrawal, for those patients who could not continue on the originally randomized medication, was azathioprine intolerance (n= 12). Five patients were switched back to triple therapy after CyA withdrawal due to rejection. Steroid intolerance was rare and CyA in low doses was very well tolerated. At 1 year there were no statistically significant differences in graft survival between groups A, B, C, and D-81 %, 88%, 88%, and 88%, respectively-or in patient survival-88%, 88%, 88%, and 97%, respectively. For those patients continuing with the originally randomized treatment protocol, there were no differences in patient or graft survival either, the means being 91% and 89%, respectively. The most common cause of death after withdrawal was cardiovascular in nature, and there were no more fatal infections under triple drug treatment than with double drug regimens. There were no statistically significant differences in mean serum creatinine values at 1 year. The median serum creatinine values for groups A, B, C, and D were 112, 132, 133, and 133 μmol/l, respectively. At 1 year the mean CyA dose in the groups that continued with CyA was 3. 5–4. 2 mg/kg per day and CyA concentrations were equal.  相似文献   
36.
One hundred and one patients, nursed in an intensive care unit for at least 24h, were monitored for bacterial colonization and infection. The infection rates were similar to those in other reports. Patients were not generally colonized with common environmental strains in the unit. Bacterial dissemination between patients was uncommon. No gentamicin resistant gram negative or Staphylococcus aureus strains were observed, nor methicillin resistant Staphylococcus aureus strains. the hypothesis that these favourable conditions are partly related to the excellent isolation and barrier nursing facilities in the unit cannot be fully substantiated.  相似文献   
37.
We report a case of a fatal toxic encephalomyelopathy in a 12-year-old girl due to prophylactic intrathecal injection of methotrexate and cytosine arabinoside, with a characteristic progressive symptomatology leading to death after 28 days. The location and type of neuropathological changes support the hypothesis of a direct toxic effect of methotrexate and/or cytosine arabinoside on structures directly exposed to the cerebrospinal fluid.  相似文献   
38.
Mice treated intraperitoneally with zymosan showed a strong inhibition of the DTHR (delayed-type hypersensitivity reaction) against sheep erythrocytes (SE), ovalbumin (OA), and alloantigen. Furthermore, the rejection time of skin transplants was nearly doubled while antibody formation against SE was significantly enhanced. When a DTHR against OA and an antibody formation against SE were induced at the same time in the same animals, than the suppressive and stimulating effects cancelled each other. These results are discussed with regard to the sensitivity of lymphocyte subpopulations, which may be different if exposed to phagocytosis-induced oxygen radicals.  相似文献   
39.
40.
The growth of a panel of eight different human glioblastoma cell lines was examined in a human tumor cloning assay in agar, a tritiated thymidine uptake assay, and by counting cell numbers, in cultures performed in the absence or presence of increasing concentrations (1 to 100 ng/ml) of recombinant human stem cell factor (SCF). Growth of 7 of 8 cell lines was not significantly and reproducibly affected by recombinant human SCF. However, growth of the CRL 1620 cell line could be stimulated up to 5-fold by the cytokine. In contrast to the other cell lines investigated, CRL 1620 expressed the c-kit protooncogene assessed on the mRNA and protein level. Furthermore, SCF-induced proliferation of CRL 1620 cells was sensitive to the tyrosine kinase inhibitor erbstatin. Our data suggest that SCF can be operative in growth modulation of malignant cells outside the hematopoietic system, and this finding should be further studied for its possible clinical implications.  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