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   8283篇
  免费   661篇
  国内免费   41篇
耳鼻咽喉   56篇
儿科学   418篇
妇产科学   211篇
基础医学   1098篇
口腔科学   160篇
临床医学   1285篇
内科学   1297篇
皮肤病学   120篇
神经病学   649篇
特种医学   157篇
外科学   933篇
综合类   112篇
一般理论   6篇
预防医学   1036篇
眼科学   266篇
药学   682篇
中国医学   13篇
肿瘤学   486篇
  2023年   39篇
  2022年   50篇
  2021年   173篇
  2020年   113篇
  2019年   156篇
  2018年   151篇
  2017年   129篇
  2016年   131篇
  2015年   176篇
  2014年   240篇
  2013年   381篇
  2012年   486篇
  2011年   598篇
  2010年   321篇
  2009年   293篇
  2008年   522篇
  2007年   550篇
  2006年   554篇
  2005年   555篇
  2004年   509篇
  2003年   407篇
  2002年   470篇
  2001年   115篇
  2000年   106篇
  1999年   102篇
  1998年   115篇
  1997年   80篇
  1996年   69篇
  1995年   53篇
  1994年   64篇
  1993年   52篇
  1992年   87篇
  1991年   73篇
  1990年   74篇
  1989年   56篇
  1988年   63篇
  1987年   62篇
  1986年   65篇
  1985年   58篇
  1984年   61篇
  1983年   50篇
  1982年   57篇
  1981年   52篇
  1980年   52篇
  1979年   36篇
  1978年   34篇
  1977年   27篇
  1975年   26篇
  1974年   31篇
  1971年   31篇
排序方式: 共有8985条查询结果,搜索用时 15 毫秒
991.
992.
Computed tomography (CT) remains the optimal imaging modality for diagnosing tumors in the mesentery. Although primary neoplasms arising from the mesenchymal tissues of the mesentery are rare, the small bowel mesentery is a major avenue for the dissemination of tumor within the peritoneal cavity. Tumors spread to the mesentery by four major routes: (a) direct extension, commonly seen with carcinoid tumor of the small intestine as well as intraabdominal cancers such as pancreatic and colon cancer; (b) lymphatic dissemination of lymphoma and some epithelial malignancies; (c) hematogenic spread resulting in embolic metastases to the small intestinal wall, usually seen in melanoma and breast cancer; and (d) seeding through the peritoneum from ovarian and gastrointestinal malignancies as well as some lymphomas. Although percutaneous imaging-guided or surgical biopsy is often necessary to guide management, analysis of CT features along with the clinical history may be useful in differentiating mesenteric tumors from infectious, inflammatory, or vascular processes affecting the mesentery. The article presents the characteristic appearances of primary and secondary mesenteric neoplasms at CT and offers a rational approach to the differential diagnosis of mesenteric masses depicted at CT.  相似文献   
993.
994.
This study reports the Emory experience with 147 distal splenorenal shunts (DSRS) and 110 orthotopic liver transplants (OLT) between January 1987 and December 1991. The purpose was to clarify which patients with variceal bleeding should be treated by DSRS versus OLT. Distal splenorenal shunts were selected for patients with adequate or good liver function. Orthotopic liver transplant was offered to patients with end-stage liver disease who fulfilled other selection criteria. The DSRS group comprised 71 Child's A, 70 Child's B, and 6 Child's C patients. The mean galactose elimination capacity for all DSRS patients was 330 +/- 98 mg/minute, which was significantly (p less than 0.01) above the galactose elimination capacity of 237 +/- 82 mg/minute in the OLT group. Survival analysis for the DSRS group showed 91% 1-year and 77% 3-year survival, which was better than the 74% 1-year and 60% 3-year survivals in the OLT group. Variceal bleeding as a major component of end-stage disease leading to OLT had significantly (p less than 0.05) poorer survival (50%) at 1 year compared with patients without variceal bleeding (80%). Hepatic function was maintained after DSRS, as measured by serum albumin and prothrombin time, but galactose elimination capacity decreased significantly (p less than 0.05) to 298 +/- 97 mg/minute. Quality of life, measured by a self-assessment questionnaire, was not significantly different in the DSRS and OLT groups. Hospital charges were significantly higher for OLT (median, $113,733) compared with DSRS ($32,674). These data support a role for selective shunt in the management of patients with variceal bleeding who require surgery and have good hepatic function. Transplantation should be reserved for patients with end-stage liver disease. A thorough evaluation, including tests of liver function, help in selection of the most appropriate therapeutic approach.  相似文献   
995.
996.
BACKGROUND: Many severely depressed patients do not benefit from or tolerate existing treatments. Repetitive transcranial magnetic stimulation (rTMS) has been reported to benefit depression. We compared rTMS to electroconvulsive therapy (ECT) in severely ill, depressed patients. METHODS: Twenty-five patients with a major depression (unipolar or bipolar) deemed clinically appropriate for ECT were randomly assigned to rTMS (10-20 treatments, 10 Hz, 110% motor threshold applied to the left dorsolateral prefrontal cortex for a total of 10,000-20,000 stimulations) or a course of bitemporal ECT (4-12 treatments). The primary outcome measure was the 24-item Hamilton Depression Rating Scale (HDRS). The Brief Psychiatric Rating Scale (BPRS), Young Mania Rating Scale (YMS), and Clinical Global Impression scale (CGI) were secondary measures. Minimal rescue medications were utilized. RESULTS: Mean percent improvement on the baseline HDRS score did not significantly differ between the two treatments (i.e., 55% for the rTMS group vs. 64% for the ECT group [p = ns]). With response defined as a 50% reduction from baseline and a final score < or = 8 on the HDRS, there was also no significant difference between the two groups. We did not observe any differences between groups on the secondary measures. CONCLUSIONS: A 2-4 week randomized, prospective trial comparing rTMS to ECT produced comparable therapeutic effects in severely depressed patients.  相似文献   
997.
Patient satisfaction is generally regarded as an important component in quality health care. However, there has been little satisfaction research in physiotherapy compared with that in other clinical fields with few qualitative studies that have explored patients' perceptions and attitudes toward physiotherapy. We report on the use of focus groups, as part of a multimethod approach of qualitative data collection into patients' satisfaction with their outpatient physiotherapy within the NHS system of care in the United Kingdom. We explored the factors that affect patients' satisfaction with musculoskeletal outpatient physiotherapy. A purposeful sample of patients with acute and chronic musculoskeletal patients who had been discharged from physiotherapy within the previous 4 months was drawn from both an inner city and suburban hospital. Two acute groups (n = 4, n = 10) and two chronic groups (n = 5, n = 11) were convened. A topic guide drew on themes that had emerged from the earlier qualitative phases of the study and guided the discussion in relation to pretreatment, treatment, and outcome stages of physiotherapy care. Sessions were tape-recorded, transcribed, and content was analyzed to code and categorise the primary patterns in the data. Although subjects in both the acute and chronic groups expected that treatment would improve their symptoms and function, they differed in the degree to which they perceived that this was achieved. Both satisfactory and unsatisfactory aspects of care emerged under the principal themes of expectations, communication, perceptions of the therapist, treatment process, and outcome. Those in the acute group were optimistic of a good result, whereas those with chronic degenerative conditions were either doubtful of improvement or unrealistic in their hopes for complete resolution of their symptoms. It was also apparent that subjects could be further divided into one of three groups (positive, negative, ambivalent), depending on the degree to which they perceived their needs and expectations had been met. Verbatim comments are presented to illustrate the spectrum of views expressed. The therapeutic encounter between therapist and patient is complex and reflects the multidimensional construct of satisfaction. Focus groups were used in this study as part of a multimethod approach into patient satisfaction with outpatient physiotherapy; they provided additional valuable insight into the reasoning process behind patients' evaluation of their care. Establishing patients' needs, particularly the extent to which these might be psychosocial rather than physical, could point the way to a more patient-focussed and productive physiotherapy experience. Although rich in-depth information was obtained from this study, caution should be applied in generalizing the findings because of the small sample sizes and the setting of the study within the NHS system of care. Therefore, further work to identify the full spectrum of issues relating to patients' satisfaction with their outpatient care is indicated.  相似文献   
998.
Over the last 20 years, the Canadian Blood Services' (CBS) Donor Health Assessment Questionnaire (DHAQ), used to screen prospective blood donors to determine their eligibility, has grown in complexity and length. Its growth is inextricably linked to the evolution of the environment within which CBS operates from unregulated collection and distribution of labile blood products to a fully regulated environment and to the need to satisfy both Health Canada and US Food and Drug Administration (FDA) requirements. Within this context, the development of the CBS DHAQ has been characterized by addition of questions and items without any periodic reevaluation of the need for retaining existing questions and/or items. In this review, we apply principles from cognitive science relating to how people think when answering questionnaires to the situation of blood donors completing the DHAQ. We show that some items that were added at different times in separate questions, for reasons that were historically relevant, could be now asked more simply with a single question. The historical development of the DHAQ, resulting in the condensing of many items into lists, the use of complex wording, and the sheer number of items included in the questionnaire make accurate retrieval of information from the donor's memory difficult. Thus, we believe that redesigning the DHAQ will improve the quality and accuracy of the donors' answers to screening questions.  相似文献   
999.
Autosomal-dominant polycystic kidney disease (AD-PKD) is the most prevalent inherited genetic disease of cats, particularly affecting Persians. Until recently the condition has been diagnosed by renal ultrasound screening. With the identification of the genetic mutation responsible for AD-PKD it is now possible to use advanced molecular techniques to screen for the disease. We have developed a rapid, sensitive and specific real-time PCR genotyping assay that can detect the single nucleotide polymorphism responsible for AD-PKD. Of 72 UK Persian and Exotic Shorthair cats submitted for AD-PKD ultrasound screening, 29 were found to have the disease, 41 were negative and 2 were equivocal. The recently published PCR-RFLP method showed the AD-PKD mutation to be present in all 29 diseased cats and absent in the 41 negative and 2 equivocal cats. Our real-time PCR genotyping assay was in complete agreement with the PCR-RFLP results. Of 600 blood or buccal swabs analysed from April 2005 to January 2006, 165 were found to be AD-PKD positive and 435 were negative, giving a prevalence of 27.5%. All 194 cats with AD-PKD were found to be heterozygous for the mutation.  相似文献   
1000.
Cadell S  Marshall S 《Death Studies》2007,31(6):537-548
The aim of this study was to explore individuals' self-construals after the loss of a partner from HIV/AIDS for whom they were a caregiver. Seven gay or transsexual bereaved caregivers were interviewed after the death of their partners. The data revealed patterns suggestive of A. Aron and E. N. Aron's (1986) “inclusion of others in the self” (IOS) with partners described as part of participants' identity. Using the metaphor of the IOS, the results illustrate how care-giving became a part of the self as well as aspects of the partner. Upon the death of the partner, the loss resulted in a crisis of meaning due to the loss of the person and relationship that had contributed significance and purpose to life. Regaining meaning involved making sense of both the relationship and the caregiving role.  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