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   2900篇
  免费   310篇
  国内免费   33篇
耳鼻咽喉   24篇
儿科学   89篇
妇产科学   56篇
基础医学   351篇
口腔科学   167篇
临床医学   438篇
内科学   502篇
皮肤病学   26篇
神经病学   174篇
特种医学   123篇
外国民族医学   1篇
外科学   284篇
综合类   76篇
预防医学   380篇
眼科学   125篇
药学   207篇
中国医学   4篇
肿瘤学   216篇
  2019年   30篇
  2018年   43篇
  2016年   25篇
  2015年   25篇
  2014年   65篇
  2013年   88篇
  2012年   114篇
  2011年   98篇
  2010年   64篇
  2009年   62篇
  2008年   93篇
  2007年   126篇
  2006年   116篇
  2005年   114篇
  2004年   84篇
  2003年   94篇
  2002年   99篇
  2001年   102篇
  2000年   84篇
  1999年   91篇
  1998年   42篇
  1997年   32篇
  1996年   36篇
  1995年   45篇
  1994年   43篇
  1993年   33篇
  1992年   75篇
  1991年   70篇
  1990年   74篇
  1989年   72篇
  1988年   90篇
  1987年   90篇
  1986年   62篇
  1985年   77篇
  1984年   57篇
  1983年   49篇
  1982年   28篇
  1981年   31篇
  1979年   38篇
  1978年   27篇
  1977年   41篇
  1976年   26篇
  1975年   32篇
  1974年   37篇
  1973年   33篇
  1972年   33篇
  1971年   26篇
  1970年   26篇
  1969年   23篇
  1967年   29篇
排序方式: 共有3243条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
Relaxing retinotomies. Analysis of anatomic and visual results   总被引:6,自引:0,他引:6  
L S Morse  B W McCuen  R Machemer 《Ophthalmology》1990,97(5):642-7; discussion 647-8
The authors analyzed 100 consecutive eyes undergoing relaxing retinotomies to determine the anatomic and visual results associated with the use of this procedure. With a minimum follow-up of 6 months, 58 eyes were completely attached, 8 were partially attached (macula on), and 34 were detached. Thirty-four percent of all eyes and 50% of attached eyes obtained a visual acuity of 5/200 or greater at 6 months. At last examination, 29% of all eyes and 43% of attached eyes had a visual acuity of at least 5/200. Eyes that had circumferential relaxing retinotomies involving the entire temporal quadrant generally had lower visual acuities when compared with eyes that had relaxing retinotomies sparing the entire temporal quadrant. The use of a radial relaxing retinotomy also was associated with lower final visual acuity. The length of the relaxing retinotomy or the placement of the relaxing retinotomy either anterior or posterior to the encircling scleral buckle did not appear to influence the anatomic or visual results. Hypotony (intraocular pressure less than 5 mmHg) was seen in 43% of reattached eyes.  相似文献   
5.
The role of an operation in patients receiving neoadjuvant chemotherapy for clinically localized but invasive transitional cell carcinoma of the bladder currently is evolving. An operation is essential for case selection and evaluation of local response but it also contributes to bladder preservation and survival. The procedure that is necessary to select for and assess response to chemotherapy may itself alter the actual or proceed to evolution of invasive bladder cancer. Neoadjuvant chemotherapy is a reasonable therapeutic strategy in selected patients but it remains to be seen whether the results will prove to be superior to those achieved with standard endoscopic and open operations.  相似文献   
6.
7.
Neuroimaging in Pineal Tumors   总被引:4,自引:0,他引:4  
F Reis  MD  AV Faria  MD  PhD  VA Zanardi  MD  PhD  JR Menezes  MD  F Cendes  MD  PhD  LS Queiroz  MD  PhD 《Journal of neuroimaging》2006,16(1):52-58
BACKGROUND AND PURPOSE: The authors report radiological findings in 11 tumors in the pineal region, which were histologically diagnosed as germinomas, pineocytomas pineoblastomas, ependymomas, teratomas, and astrocytomas. METHODS: Computed tomography (CT) was performed in seven patients and magnetic resonance imaging (MRI) was performed in all patients. RESULTS: CT showed a solid or solid/cystic mass with variable contrast enhancement. MRI showed a heterogeneous mass, with hypointense signal on T1 and iso/hyperintense signal on T2-weighted images (WI) and gadolinium enhancement. Extension to adjacent structures occurred in five patients and spread through the cerebral spinal fluid (CSF) in two. CONCLUSIONS: Pineal region tumors have no pathognomonic imaging pattern. MRI and CT are complementary in diagnosis and are important to determine localization, extension, and meningeal spread.  相似文献   
8.
9.
We treated 13 patients with a second 125iodine implant for local recurrence of prostatic carcinoma. All patients had biopsy proved palpable recurrence without evidence of distant metastases. Full doses of irradiation were used (median matched peripheral dose 170 Gy.). Six patients had complete regression of palpable recurrence, 2 had partial regression, 2 had no apparent response and 3 were unevaluable for local response. Actuarial freedom from local disease progression at 5 years was 51%. Despite a relatively high rate of local disease control the actuarial rate of distant metastases reached 100% at 6 years after reimplantation. There were 2 severe rectal complications and 4 instances of mild to moderate urinary incontinence among the 13 patients. Local regression of recurrent prostatic carcinoma may be achieved with 125iodine reimplantation but most patients still had distant metastases.  相似文献   
10.
Phosphorylated zidovudine (ZDV) concentrations may provide a link between drug exposure and clinical efficacy since these would include the active, intracellular form of the drug, ZDV triphosphate. Many groups are investigating the optimal methodology that can be used to accomplish this goal. The initial purpose of the present studies was to examine the effect of the inclusion of cell wash steps on the quantitation of intracellular ZDV. Ten milliliters of whole blood collected from healthy volunteers was spiked with increasing ZDV concentrations (0.187, 0.375, 1.87, and 3.75 microM), allowed to equilibrate at room temperature for 1 h, and separated into whole-blood components by a density gradient procedure. A mononuclear cell pellet was obtained, reconstituted with 2 ml of phosphate-buffered saline (PBS), and split into two aliquots, one of which was not washed at all and the other of which was washed four times with 1 ml of PBS. All samples were analyzed by ZDV radioimmunoassay (RIA) after a 1:1 dilution with either 1 mg of alkaline phosphatase (type 1-S; Sigma) per ml or PBS. Parent ZDV was measured in those samples which were not treated with the enzyme, while total ZDV was measured in those samples which were exposed to alkaline phosphatase (21 degrees C for 1 h). The result of the difference between the two samples is total phosphorylated ZDV. During the experiment, evidence of alkaline phosphatase interference with the RIA became apparent, confusing interpretation of intracellular ZDV concentrations. This evidence was based on three sets of data. First, wash samples showed increases in ZDV concentrations of as great as 0.127 microgramM after exposure to alkaline phosphatase, even though on microscopic inspection the wash samples were acellular. Second, the sum of total ZDV recovered from the four wash samples plus the washed cell pellet was as much as 14-fold greater than the total ZDV measured in the unwashed cell pellet. Theoretically, at least, these two entities should be equal. Finally, control samples of alkaline phosphatase in PBS (0.5 mg/ml) run directly through the assay measured false ZDV levels ranging from 0.002 to 0.075 microgramM (0.6 to 20 ng/ml). Alkaline phosphatase is frequently used to measure phosphorylated anabolites of ZDV in peripheral blood mononuclear cells. These data show that the particular form of alkaline phosphatase used may interfere with the ZDV RIA and may confuse the interpretation of phosphorylated anabolite concentrations of ZDV.  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