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   4931篇
  免费   187篇
  国内免费   46篇
耳鼻咽喉   124篇
儿科学   275篇
妇产科学   293篇
基础医学   367篇
口腔科学   178篇
临床医学   402篇
内科学   953篇
皮肤病学   69篇
神经病学   319篇
特种医学   246篇
外科学   1218篇
综合类   65篇
一般理论   2篇
预防医学   117篇
眼科学   184篇
药学   158篇
中国医学   15篇
肿瘤学   179篇
  2023年   31篇
  2022年   43篇
  2021年   96篇
  2020年   76篇
  2019年   74篇
  2018年   130篇
  2017年   102篇
  2016年   141篇
  2015年   169篇
  2014年   202篇
  2013年   245篇
  2012年   343篇
  2011年   297篇
  2010年   193篇
  2009年   155篇
  2008年   318篇
  2007年   417篇
  2006年   369篇
  2005年   389篇
  2004年   355篇
  2003年   302篇
  2002年   246篇
  2001年   98篇
  2000年   71篇
  1999年   61篇
  1998年   42篇
  1997年   35篇
  1996年   27篇
  1995年   22篇
  1994年   20篇
  1993年   8篇
  1992年   21篇
  1991年   13篇
  1990年   6篇
  1989年   3篇
  1988年   2篇
  1987年   3篇
  1986年   3篇
  1985年   2篇
  1984年   2篇
  1983年   2篇
  1982年   4篇
  1979年   2篇
  1978年   2篇
  1976年   5篇
  1974年   3篇
  1970年   2篇
  1966年   2篇
  1963年   2篇
  1959年   1篇
排序方式: 共有5164条查询结果,搜索用时 187 毫秒
991.
Objective: Spastic disorders are considered as important cerebral complications of subarachnoid hemorrhage (SAH). However, there has been no research concerning the pathophysiological mechanism of its link with the spinal cord. The present study aimed to assess the relationship between the development of spasticity and neuronal degeneration after SAH and increase in spinal cord pressure after central canal hemorrhage (CCH).Participants: Twenty-three rabbits were included.Outcome measures: Of all rabbits, 5, 5, and 13 were allocated in the control, SHAM and study groups, respectively. Moreover, 1 cc of saline and 1 cc of autologous arterial blood were injected into the cisterna magna of the SHAM and study groups, respectively. The Muscle spasticity tension values (MSTVs) were determined according to the modified Ashworth scale. Degenerated neuron densities (DND) in the gray matter (GM) of each animal''s spinal cord were stereologically calculated.Results: The average MSTV of each group was as follows: control group (n = 5) 2; SHAM group (n = 5) 3-5; and study group (n = 13) 8–10. The DND values of the spinal cord of each group were as follows: control group, 2 ± 1/mm3; SHAM group, 12 ± 3/mm3; and study group, 34 ± 9/mm3. Results showed an important linear relationship between the MSTVs and the DND of the spinal cord (P < 0.001).Conclusion: Spasticity may be attributed to other causes such as ischemic neurodegenerative process that develops after spinal SAH and the de-synchronization of the flexor-extensor muscles due to the spontaneous discharge of interneuronal structures, which are crossed within the spinal cord owing to the build-up of pressure after CCH.  相似文献   
992.
993.
PURPOSE: To determine the concentration of hydroxyproline (Hyp) in aqueous humor and serum samples of patients with and without pseudoexfoliation (PEX). PATIENTS AND METHODS: Aqueous humor and serum Hyp levels were measured in cataract patients. Patients were divided into PEX and control groups. Samples were obtained from 27 cataract patients with PEX and 25 cataract patients without PEX. Patients had no elevated intraocular pressure or glaucoma. Hyp concentration was determined spectrophotometrically. RESULTS: Mean Hyp concentration in the PEX aqueous (0.86+/-0.27 mg/L) and serum (40.8+/-6.14 mg/L) samples was significantly higher than that measured in the control aqueous (0.56+/-0.2 mg/L) and serum (34.51+/-6.82 mg/L) samples, respectively (P<0.001, P=0.001). No significant correlation could be found between aqueous humor and serum Hyp concentrations. CONCLUSIONS: The higher levels of Hyp could be a sign of increased collagen turnover in PEX syndrome.  相似文献   
994.
PURPOSE: To evaluate the effectiveness of laser-assisted subepithelial keratectomy (LASEK) to treat residual refractive errors after laser in situ keratomileusis (LASIK). SETTINGS: Isik Eye Clinic, Ankara, Turkey. METHODS: This retrospective study included 24 eyes of 15 patients who had retreatment by LASEK for residual refractive errors after myopic LASIK. All patients had examinations that included slitlamp biomicroscopy, subjective and cycloplegic refractions, uncorrected visual acuity (UCVA), best corrected visual acuity, corneal topography, and pachymetry preoperatively and postoperatively. Postoperative examinations were performed at 1 week and 1, 3, and 6 months. RESULTS: The patient cohort comprised 9 men and 6 women. The median spherical equivalent (SE) of attempted correction for retreatment with LASEK was -1.25 diopters (D). The median follow-up after LASEK was 11.5 months (range 6 to 16 months). At the end of the follow-up, the median SE of the refractive error was -0.38 D. The median UCVA increased from 20/45 before LASEK to 20/25 at the last follow-up visit, which was statistically significant (P<.001). After LASEK, significant postoperative haze developed in 5 eyes. In all 5 eyes, the estimated ablation depth was more than 40 mum and the SE of attempted correction was -2.00 D or greater. CONCLUSIONS: Laser-assisted subepithelial keratectomy retreatment in eyes with myopic regression after LASIK resulted in a significant improvement in UCVA that was comparable to the improvement after flap lifting. An SE of attempted correction greater than -2.00 D was associated with a significant rate of haze.  相似文献   
995.
PURPOSE: To compare the effectiveness of brinzolamide 1%, brimonidine 0.2%, acetazolamide 250 mg, intracameral acetylcholine, and timolol 0.5% in preventing intraocular pressure (IOP) peaks during the early period after phacoemulsification in which sodium chondroitin sulfate 4%-sodium hyaluronate 3% (Viscoat) was used as the ophthalmic viscosurgical device (OVD). SETTING: Department of Ophthalmology, Baskent University Medical Faculty, Ankara, Turkey. METHODS: This prospective randomized study comprised 185 eyes of 185 patients with uncomplicated cataract scheduled for phacoemulsification using Viscoat as the OVD. Patients were randomly assigned to 1 of 6 groups: postoperative application of topical brinzolamide 1%, brimonidine 0.2%, oral acetazolamide 250 mg, intracameral acetylcholine, timolol 0.5%, or no ocular hypotensive agent (control group). The IOP was measured at baseline (preoperatively) as well as 6 hours, 20 to 24 hours, and 1 week after surgery. RESULTS: The mean preoperative IOP values were not significantly different between the groups. Six hours and 20 to 24 hours postoperatively, the mean IOP was significantly lower in all groups receiving an ocular hypotensive agent than in the control group (P<.01). Six hours after surgery, the mean IOP significantly increased in all groups but was higher in the control group. At 20 to 24 hours, the mean IOP decreased significantly in all ocular hypotensive agent groups but remained significantly high in the control group. One week after surgery, there were no significant differences between the groups. CONCLUSION: Brinzolamide, brimonidine, acetazolamide, intracameral acetylcholine, and timolol had similar effects in reducing IOP increases after phacoemulsification performed using Viscoat.  相似文献   
996.
In this experimental study on endometriosis, the majority of the implants were successfully detected with technetium-(99mTc) labeled red blood cell scintigraphy.  相似文献   
997.
A group of 140 women with a body mass index (BMI) < or = 24 kg/m(2) undergoing 291 cycles was compared with a group of 138 women with a BMI >24 kg/m(2) in 291 cycles, with respect to duration of ovarian stimulation and dose of gonadotrophin, number of oocytes collected, cleavage and implantation rate, clinical pregnancy, miscarriage and delivery rates. Patients with a BMI > 24 kg/m(2) demonstrated a significant decrease in the number of follicles after stimulation (P = 0.01), a comparative increase in the number ampoules of gonadotrophin used (P = 0.03) and a lower number of eggs collected (P = 0.05). The mean number of embryos on days 1, 2 and 3 was significantly lower in the group with BMI > 24 kg/m(2) (P < 0.001). No significant difference was found in clinical pregnancy and miscarriage rates between the two groups. In spite of the lower response in women with BMI > 24 kg/m(2), the delivery rate per retrieval was not different (24.6 versus 24.8%). These results indicate a lower stimulation response in women with elevated BMI, but no adverse effect on IVF outcome. In relation to wellbeing, however, it is recommended that patients with a high BMI reduce their weight before IVF treatment.  相似文献   
998.
999.
Ovarian carcinoma is a malignancy with a poor prognosis especially in patients with advanced disease. The majority of patients with ovarian serous carcinoma are diagnosed in advanced stages. Palpable extraabdominal lymphadenopathy at the time of presentation is distinctly uncommon. This case report addresses a patient with serous ovarian carcinoma presenting as left supraclavicular lymphadenopathy (Virchow's node) and no other symptoms. Not only thyroid or thoracic malignancies but also ovarian malignancies like serous ovarian carcinoma could present with a supraclavicular lymph node without any other symptoms.  相似文献   
1000.
Endometrial stromal sarcoma (ESS) is a rare mesenchymal tumor with characteristic histological appearances, consisting of diffuse infiltrate of small uniform endometrial stromal cells with a multinodular arrangement and distinct vascular pattern. Less common variants of ESS include "mixed endometrial stromal and smooth muscle tumors", "endometrial stromal tumors resembling ovarian sex cord tumors" and "endometrial stromal neoplasms with endometrial glands", and "aggressive endometriosis". Rarely do endometrial stromal tumors have a prominent fibrous or myxoid appearance which causes confusion and possible misdiagnosis as myxoid leiomyosarcoma. In this report we present a very unusual subtype of ESS in a 32-year-old woman. The tumor revealed atypical pleomorphic bizarre cells which were stained positive only with vimentin and CD10 in an abundant myxoid matrix. A low-proliferative rate was established with MIB-1 staining. To our knowledge such appearance has not been previously reported.  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