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   18977篇
  免费   1679篇
  国内免费   39篇
耳鼻咽喉   150篇
儿科学   636篇
妇产科学   380篇
基础医学   2852篇
口腔科学   178篇
临床医学   2402篇
内科学   3631篇
皮肤病学   255篇
神经病学   1930篇
特种医学   563篇
外科学   2446篇
综合类   234篇
一般理论   22篇
预防医学   2240篇
眼科学   277篇
药学   1264篇
中国医学   19篇
肿瘤学   1216篇
  2023年   255篇
  2022年   316篇
  2021年   640篇
  2020年   412篇
  2019年   692篇
  2018年   688篇
  2017年   462篇
  2016年   504篇
  2015年   522篇
  2014年   651篇
  2013年   963篇
  2012年   1406篇
  2011年   1376篇
  2010年   703篇
  2009年   644篇
  2008年   1017篇
  2007年   1048篇
  2006年   1077篇
  2005年   979篇
  2004年   823篇
  2003年   797篇
  2002年   775篇
  2001年   257篇
  2000年   220篇
  1999年   219篇
  1998年   163篇
  1997年   154篇
  1996年   123篇
  1995年   119篇
  1994年   93篇
  1993年   99篇
  1992年   160篇
  1991年   166篇
  1990年   178篇
  1989年   145篇
  1988年   140篇
  1987年   135篇
  1986年   104篇
  1985年   100篇
  1984年   96篇
  1983年   100篇
  1982年   75篇
  1981年   83篇
  1979年   72篇
  1978年   58篇
  1977年   67篇
  1976年   65篇
  1974年   64篇
  1971年   62篇
  1969年   59篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
Background: The slitlamp can be used to estimate the anterior chamber depth (ACD). The length of a slit object is increased until the corneal and iris/lens images appear to just touch. Multiplying the just‐touching‐slit‐length (JTSL) by a conversion factor gives an estimate of the ACD as measured by ultrasonography. The purpose of this study was to determine if central corneal thickness (CCT) affects the accuracy of this technique. Methods: The ACD of 50 subjects was measured by A‐scan ultrasonography and estimated by the slitlamp technique. CCT was measured by ultrasonic pachometry. The refractive error was determined subjectively. Results: The average ultrasonographic ACD for all subjects was 3.32 ± 0.65 mm. The average JTSL was 2.46 ± 0.38 mm. The conversion ratio between the ultrasonographic ACD and the average JTSL was 1.35. The predicted ACD using the regression equation of JTSL on the ultrasound anterior chamber depth (USACD) was 3.32 ± 0.54 mm. The corresponding value using the regression equation of JTSL and CCT on USACD was exactly the same, that is, 3.32 ± 0.54 mm. Conclusion: Incorporation of CCT into a regression equation does not improve the accuracy of the Smith technique.  相似文献   
52.
53.
54.
Changes in the design of hospital wards have usually been determined by architects and members of the nursing and medical professions, the views and preferences of patients have seldom been sought directly The Hospital Anxiety and Depression scale and the Disturbance Due to Hospital Noise questionnaire were administered to 64 female patients on bay and Nightingale wards together with a questionnaire designed for this study Perceptions of social and physical factors of ward design were examined, and their relationship to psychological well-being and sleep patterns The results show that the bay ward seemed to offer a more favourable environment for patients but some of the disadvantages of bay wards are balanced by better staffing levels and better and more modern facilities Visibility to nurses was lower on the bay ward The Nightingale ward was perceived as significantly noisier than the bay ward and noise levels were significantly correlated to anxiety scores Paradoxically the increase in noise levels appeared to improve the perceived level of privacy on the Nightingale ward Seventy-five per cent of patients were found to prefer the bay ward design, and since neither design appears to have major disadvantages their continued introduction should be encouraged However, recommendations are made concerning the optimizing of patients' well-being within the bay ward setting  相似文献   
55.
Measurements of the sella turcica (depth, length, width, volume, thickness of the floor, intraclinoid distance, length of tuberculum sellae) were made in cadaver sphenoid blocks, skulls, and in patients undergoing transsphenoidal surgery. Variations in the sphenoidal septae, sinuses and bulging of surrounding structures (carotid arteries and optic nerves) were studied. Results were compared with observations made during surgery and with data reported in the literature. Anatomic variations of the sella turcica and sphenoid sinus may complicate surgical intervention in the region of the sella turcica. However, these variations were never, in our experience, the cause for interruption of transsphenoidal surgery.  相似文献   
56.
Homing receptor is a membrane lectin of 110 kd molecular weight that recognizes galactosyl and mannosyl residues of an as yet unknown glycoconjugate. It is responsible for recognition and selective homing of hemopoietic progenitor cells after these cells are transplanted intravenously. Consequently, it is present on the surface of hemopoietic progenitor cells. To determine the distribution of this receptor on other cell types we performed standard binding assays in many cell types using galactosyl and mannosyl residues covalently bound to bovine serum albumin (G-BSA and M-BSA) as an index of homing receptor. BSA moiety was then labeled with 125I. The three cloned hemopoietic cell lines B6Sut, FDCP-1, and FDCP-mix all showed combined binding of G-BSA and M-BSA, whereas the lymphoid cell line L1210 showed only M-BSA, not G-BSA binding and, therefore, was considered to lack homing receptors. Similarly, stromal cell lines D2X and GB1/6 as well as primary marrow stroma (progenitor cell-depleted) did not show homing receptors as evidenced by combined binding of G-BSA and M-BSA. Nor did the nonhemopoietic stromal cell line Swiss 3T3 show the presence of homing receptors by these criteria. We conclude that homing receptors are distributed narrowly and are present on hemopoietic progenitor cells, but absent on hemopoietic stroma.  相似文献   
57.
One-hundred consecutive patients were prospectively evaluated on admission to our Brain Injury Unit for signs and symptoms of reflex sympathetic dystrophy (RSD) in the upper extremity. Patients averaged 4 months postinjury and had an average age of 29 years. Thirteen patients had clinical signs and symptoms of RSD and were then evaluated with standard radiographs and 3-phase radionuclide scintigraphy. Twelve of 13 patients had 3-phase bone scans (TPBS) consistent with RSD (12% overall incidence). RSD was present exclusively in the spastic upper extremity. There were 9 patients with hemiparesis and 3 with quadraparesis. There was a significantly higher (P < 0.01) incidence of associated upper extremity injury in the group with RSD (75%). All patients had a mean Rancho Cognitive Level of V and initial Glasgow Coma Scores less than 8. Patients who developed RSD had lower Glasgow Coma Scores than the non-RSD patients. Brain-injured patients often display agitation, hyperalgesia, disuse or neglect of the RSD-involved extremity. In addition, these patients are often cognitively unable to vocalize complaints of pain. Undiagnosed RSD in these patients can result in a significant delay in rehabilitation and possible loss of the use of an otherwise functional upper extremity.  相似文献   
58.
Summary A total of 16 patients with recurrent epithelial ovarian cancer were treated with sulofenur (LY 186641), a novel oral sulfonylurea. All subjects had received previous chemotherapy. Anaemia occurred in all 16 patients, 14 of whom required a blood transfusion, and 2/16 patients received methylene blue for breathlessness due to methaemaglobinaemia. Treatment was discontinued in 2/16 cases due to rising liver enzyme values, which reverted to normal on cessation of the drug. There was no nausea or alopecia. Only two minor responses were seen. Plasma drug levels were insufficient to result in antitumour activity as extrapolated from animal data. Further studies that attempt to increase the bioavailability and improve the therapeutic index are warranted.  相似文献   
59.
High-frequency deep brain stimulation (DBS) of the subthalamic nucleus (STN) improves the motor symptoms of Parkinson's disease (PD). Opposite changes in mood, such as mania or depression, have been reported after surgery, but it is not known whether these side effects are specifically related to STN DBS. To learn whether STN DBS also influences the limbic loop, we investigated acute subjective psychotropic effects related to levodopa or bilateral STN DBS. After a median postoperative follow-up of 12 months, 50 PD patients completed the Addiction Research Center Inventory (ARCI), assessing subjective psychotropic effects in four conditions: off-drug/on-stimulation; off-drug/off-stimulation; on-drug/off-stimulation; and on-drug/on-stimulation. Both levodopa and STN DBS improved all the ARCI subscales, indicating subjective feelings of well being, euphoria, increase in motivation, and decrease in fatigue, anxiety, and tension. A suprathreshold dose of levodopa was significantly more effective than STN DBS, using the same electrical parameters as for chronic stimulation, on four of the five ARCI subscales. We concluded that 1) both STN DBS and levodopa have synergistic acute beneficial psychotropic effects in PD, 2) the psychotropic effects of both treatments need to be considered in the long-term management of chronic STN DBS, and 3) the results indicate an involvement of the limbic STN in mood disorders of PD.  相似文献   
60.
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